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Microcross GX-Linux™ User Guide

1. cross Linux Embedded Linux Made Easy Microcross GX Linux Professional Embedded Linux Development Solution User Guide Version 1 0e 20051015 2005 Microcross Inc Licensed Materials MICROCROSS PRESS Powered by GNU X Tools SlickEdit amp Linux OS ii E GX Linux User Guide ISBN N A Microcross Inc 104 Borders Way Suite 100 Warner Robins GA 31088 2005 Microcross Inc All rights reserved This document and the GX Linux Embedded Linux BSP described in it are furnished under license with Microcross and as such may be used or copied only in accordance with the terms of the license The contents of this document are furnished for informational purposes only and are subject to change without notice Microcross assumes no responsibility or liability for any errors or inaccuracies that may exist in this document No part of this document may be reproduced stored in a retrieval system or transmitted in any form without the prior written consent of Microcross Trademarks GX Linux Visual X Tools and GNU X Tools MICROCROSS PRESS and Microcross are all trademarks of Microcross Inc All other brand and product names services names trademarks and copyrights are the property of their respective owners This documentation contains copyright materials and has been prepared by Microcross Technical Publications contact the Microcross Technical Publications staff for more information
2. IMPORTANT When using DHCP BootP the new IP address should be annotated in your notes because you will need this IP address for loading GX Linux files via TFTP If your DHCP BootP server assigns a different IP address every time you reboot MicroMonitor you may want to consider manually setting the network IP address while in the development phase of your project because the IP address is a key parameter to your TFTP communications between the host development platform and the target board Step 3 Modify Environment Variables Open Visual X Tools or another editor and edit the master Makefile in the build directory The build directory is Cygwin home gxlinux directory Edit configuration variables as follows ARCH lt arch of target gt i e arm mips ppc etc BOARD lt csbxxx gt if not set enter the Cogent uUSBC name e g csb337 csb637 etc TGTIP lt IP address gt enter the IP address assigned to the target board in the last step Optionally you can modify the other configuration variables that apply but the three most important are the ones above 28 E GX Linux User Guide Section 3 Getting Started Step 4 Build All Start a GNU X Tools Shell by clicking on the desktop icon installed If there is no icon you may not have the Application Development Platform on Windows installed correctly go back to Section 2 and follow the installation instructions Make the example programs and create a
3. If you are using a network GDB connection enter the command below 44 E GX Linux User Guide Section 6 Debugging Applications Ca Usr bin cr gdbserver 5472 hello x cr The port number 5472 was selected randomly as a high port number Any high port number that doesn t conflict with existing active ports will work The command line also indicates the name of the program you intend to debug hello in this example This program is the debug able ELF program that we built and installed above If using a serial GDB connection enter the commands below See the Changing Serial Port Settings section for instructions on building the stty command into busybox stty F dev ttySl iexten echoctl 38400 cr lt target alias gt gdb dev ttyS1 hello x cr Example In either case gdbserver will respond with something like the following example pd usr bDin cr usr bin gdbserver 5472 hello x cr Process hello created pid 26 Connect lt target alias gt gdb Start the Linux workstation side of the GDB session by invoking the lt target alias gt gdb debugger This establishes a connection to the GDB server previously started on the target hardware We invoke lt target alias gt gdb while in the directory containing the debug able version of our ELF program file hello Then issue commands at the GDB command line prompt to establish the connection and load the program s debug symbols If you are using the ddd
4. The lt arc path gt should always end in bin as the tar archives are in the bin directory on the CD ROM e g xto ls install arm linu ux mnt cdrom bin xto ls install arm elf mnt cdrom bin Table 2 1 shows where the installation directories are located The usr lt target alias gt directory has two important subdirectories lib and include that contain the runtime libraries and header files If you rebuild uClibc library these are the directories where it gets installed along with the kernel headers Table 2 1 GNU X Tools Installation Directories Directory usr bin Front end binaries for the development tools like the compiler assembler utilities and debugger The tools run on the Linux host workstation and operate on files destined for the target hardware usr lt target alias gt Development tool binaries include files and libraries specific to the version of Linux being used usr lib gcc lib lt target alias gt Compiler library directory Step 6 If you do not have the tcl8 4 tks8 4 library installed on your Linux OS you may need to install the correct version that Microcross ships on the GX Linux distribution CD You can also tryout your TCL TK configuration by issuing the command lt target alias gt gdbtk and observe the start of the program if there are any errors then you know that there is a mis match in configuration Also you can check your TCL
5. follow these simple set of instructions The Ethernet driver and board configuration are setup for ethO at install time For boards with dual Ethernet the board is labeled ENETO and ENTET1 where ENETO is mapped to ethO and ENET1 to eth1 After Linux bootup to enable a second ethernet device you can manually enter the following commands in the serial terminal window ifconfig ethl lt ip address gt netmask lt netmask gt up Example 7 tecontig ecn 192 168 0 111 netmask 255 255 255 000 up To Disable either ethO or eth1 do the following ifconfig ethl down Or ifconfig ethO down You can re enable either port if no reboot has occurred by issuing ifconfig ethl up or ifconfig eth0 up Issuing ifconfig and cr shows the status of what is up and down with the dual Ethernet devices Note MAC addresses are assigned from what is set from the factory and they are labeled on the uSBC module If the uSBC supports two Ethernet MACs they will be assigned one LSB difference For example O004 232317606 00 20 for etn QO22Z3 31766700421 for etni The user may add a command sequence manually or add it to the etc init d rcS file in rootfs and varetc to be executed automatically at startup The rcS file is like an autoexec bat file in DOS that executes commands as given at startup Rebuild and load the romfs image to take the changes to rcS GX Linux User Guide E 47 Section 7 Networking Example
6. gcc pg program f 7g Generate a symbol table for debugging The g option enables debugging with the GNU debugger GDB or Visual GDB The symbols used with standard GDB are called stabs When compiling with Microcross cross compilers set the g option to produce the stabs symbols you may use gstabs as a verbose switch if you like Other symbol options include gcoff gdwarf and gdwarf2 the gcoff symbols are not Supported in Microcross GNU cross compilers however gdwarf and gdwarf2 are supported in most target CPU toolsuites IMPORTANT NOTES To perform assembly debugging of straight assembly language files s or S files you must use g or gstabs because the assembler will not generate any other symbol formats The C C compiler however will generate appropriate symbols for either gdwarf or gdwarf2 in addition to stabs When compiling with any debug option do not use optimization options You cannot optimize code and debug it correctly using the GNU tools GX Linux User Guide E 65 Section 9 How to Use GNU X Tools 9 7 6 Optimization GNU X Tools ccc incorporates a sophisticated optimizing compiler and for most target systems it usually generates faster code than with the native compiler Any Ox optimization can be used with any fx option e g gcc Os funroll loops ffast math o outfile x infile c Here are the most
7. is used The compiler may generate calls to memcmp memset and memcpy for System V and ANSI C environments or to bcopy and bzero for BSD GX Linux User Guide E 63 Section 9 How to Use GNU X Tools environments These entries are usually resolved by entries in libc These entry points should be supplied through some other mechanism when this option is specified nostdlib When linking this option tells the linker do not use the standard libraries or startup files This option is useful when you want to provide your own libraries overriding the default libraries and use your own custom startup files When used with GCC add the correct option W1 nostdlib If you plan on augmenting the standard libraries with your own libraries then do not use this option Use a GROUP and SEARCH DIR statement with appropriate arguments in the linker script see the Visual X Tools IDE User Guide or the GNU X Tools Training Guide for examples on how to create linker scripts and startfiles Oo eile Do not search the standard system directories for header files Only the directories you have specified with I options and the current project directory are searched By using both nostdinc and I you can limit the include file search path to only those directories you specify explicitly static Link only to static libraries not shared libraries When used with GCC add the correct option W1 static In GNU X To
8. options are defined for ARM architectures Option ss Description gt O S mapcs frame Generate a stack frame that is compliant with the ARM Procedure Call Standard for all functions even if this is not strictly necessary for correct execution of the code Specifying fomit frame pointer with this option will cause the stack frames not to be generated for leaf functions The default is mno apcs frame Mapcs 32 Generate code for a processor running with a 32 bit program counter and conforming to the function calling standards for the APCS 32 bit option This option replaces the m6 option of previous releases of the compiler and is now the default mapcs stack check Generate code to check the amount of stack space available upon entry to every function that actually uses some stack space If there is insufficient space available then either the function rE SUROVE split small or rE stkovf split big will be called depending upon the amount of stack space required The run time system is required to provide these functions The default is mno apcs stack check since this produces smaller code Must be used with mapcs frame GX Linux User Guide E 77 Appendix 1 GNU X Tools ARM Linux Toolsuite Option i Description o mno sched prolog Prevent the reordering of instructions in the function prolog or the merging of those instructions with the instructions in the function s body This means
9. Internet Protocol The Journaling Flash File System developed by Axis Communications in Sweden is aimed at providing a crash power down safe file system for diskless embedded devices It is released under the GPL and the current version works for the Linux 2 0 kernel series and memory mapped industry standard flash memories aka NOR flashes A Journaling Flash File System based on the original JFFS and developed by Red Hat JFFS2 offers improved performance compression RAM footprint concurrency and support for suspending flash erases and the support for hard links Joint Test Action Group specifies test framework for electronic logic components IEEE Standard 1149 1 also known as IEEE 1149 1 JTAG or Boundary Scan See K Desktop Environment A powerful Open Source graphical desktop environment for Unix workstations The core of the Linux operating system including networking The computer running the Linux operating system that is used for developing compiling and building the kernel and target file system that is loaded and executed on the SBC Minicom is a menu driven serial communication program and includes ANSI color dialing directory dial a list script language and so forth Minicom is a clone of the MS DOS Telix program The Memory Management Unit MMU is a component of a processor architecture The MMU is responsible for mapping physical addresses defined by the hardware configuration into the virt
10. M MC Embedded Systems pdf GNU Tools for Embedded Systems Everything you want to know about using GNU tools with embedded target processors MC Libraries pdf GNU C Library GNU Math Library GNU C iostream Library 11 MC Development Tools pdf Using Id Using make Using diff amp patch 12 MC Utilities pdf Using as Using Id Using binutils Using make Using diff amp patch Using info 9 5 Controlling the Tools Using the GCC The GCC GNU Compiler Collection control program can be run like the following producing an executable file from a number of C or C source files Both examples assume that the target toolsuite is installed prior to executing the build commands The examples shown are with ccc which controls the compilation of C C and assembly files Also the user must name the C files with the c extension and C files with Cc cpp or cc extensions lt target alias oqce options o lt program cout name gt lt Tirst c gt lt second c gt lt third c gt lt EOUrCIICCO s Or xtools lt target alias gt lt target alias gt 5 g e options o lt program oult mame gt lt first c gt lt Ssecond c s 58 E GX Linux User Guide Section 9 How to Use GNU X Tools Or gt xtools lt targer alias gt lt target alias gt gt OCC options One or More source Tiles o Drogram our name Or lt targev alias gt gt s goo Options C Source f116 lt target alias gt s gcc o
11. Su pport microcross com Disclaimer Microcross Inc makes no representations or warranties with respect to the contents or use of this user guide and specifically disclaims any express or implied warranties of merchantability or fitness for any particular purpose Microcross Inc reserves the right to revise this publication and to make changes to its content at any time without obligation to notify any person or entity of such revisions or changes Microcross Inc makes no representations or warranties with respect to any Microcross software and specifically disclaims any express or implied warranties of merchantability or fitness for any particular purpose Microcross Inc reserves the right to make changes to any and all parts of Microcross software at any time without any obligation to notify any person or entity of such changes GX Linux User Guide Supports Product Part Numbers MGXL400Lx xxx October 2005 Printed in USA MICROCROSS PRESS GX Linux User Guide Bi iii Table of Contents Section 1 0 Overview and System Requirement c ccccssccseeeeeeeeeeeeeeneseeeseneseneseeeenesenesans 7 Mel VCE WN assis ie areas E seed ase ae eedae canes E se eeeteaecancewacstuseae saeceaasnecseaaeteeedee es 7 1 2 Components of the GX Linux Standard Platform cccceccccsecccceeeceeeeeseececeeececeeececeeeeeseeeesseeeessaeessaeeeseeessees 7 1 3 Components of the GX Linux Professional Platform ccccceccccsecccc
12. Visual X Tools Integrated Development Environment UMON bootloader and GX Linux startup script startlinux Linux kernel v2 6 x binary for the target processor pre built uClibc Library a small C library for Embedded Linux users Busybox ona ROM filesystem with basic system utilities and example applications All GX Linux component Makefile build scripts for rebuilding binary builds for Linux kernel uClibc library BSP example applications and filesystem 8 E GX Linux User Guide Section 2 Installation and Setup Section 2 0 Installation and Setup This section covers a number of procedures to install all components of the complete Microcross GX Linux solution Section 2 4 shows how to install and setup an application development platform that can be used either for the Standard or professional platforms on a Windows host workstation The limitation to this is that a developer cannot modify and rebuild the kernel on a Windows host workstation At present the GX Linux kernel can only be rebuilt out of the box on a Professional Platform The zimage must then be copied into the gxlinux build directory on the Windows hosted Application Development Platform Section 2 1 Standard Platform Installation and Setup on a Linux Host Workstation Section 2 2 Professional Platform Installation and Setup on a Linux Host Workstation Section 2 3 Application Development Setup on Windows Available for Standard and Professional Platforms
13. and from that point on you do not need to type the alias at any point further The target alias will become part of the command line prefix i e target alias To change or exit the target alias mode type exit at the command line From Command Shell type S xtools arm linux The prompt will now show arm linuxs Issuing the following commands can be accomplished using the shortened version of tool name i gcc as ar etc provided that you perform the xtools lt target alias gt command as shown above All GX Linux sources are pre configured for cross compilation so the xtools script is not necessary 52 E GX Linux User Guide Section 9 How to Use GNU X Tools e target alias gcc Invokes all the necessary GNU compiler passes for the specific target processor toolsuite using i e arm elf mips elf ppc elf etc e target alias cpp Invokes the preprocessor that processes all of the header files and macros that the target requires e target alias gcc Invokes the C compiler that produces assembly language code from the processed C files e target allas gtt Invokes the C compiler that produces assembly language code from the processed C files e target alias gdb Invokes the GNU Debugger with command line input see Debugging with GDB in the PDF files on the GNU X Tools CD e target alias gdbtk Invokes the GNU Debugger with a visual GUI interface called Visual GDB by Microcross a k a Insight e targ
14. as the CD ROM mount point If your default mount point is different you can change the default value by editing usr bin xtools file If you would like to override the default path to the distribution medium you may enter the command as xtools install arm linux lt arc path gt The lt arc path gt should always end in bin as the tar archives are in the bin directory on the CD ROM e g xtools install arm linux mnt cdrom bin t xtCOOLS install arm elt mnt cdrom bin Table 2 4 shows where the installation directories are located The usr lt target alias gt directory has two important subdirectories lib and include that contain the runtime libraries and header files If you rebuild uClibc library these are the directories where it gets installed along with the kernel headers Table 2 4 GNU X Tools Installation Directories usr bin Front end binaries for the development tools like the compiler assembler utilities and debugger The tools run on the Linux host workstation and operate on files destined for the target hardware usr lt target alias gt Development tool binaries include files and libraries specific to the version of Linux being used usr lib gcc lib lt target alias gt Compiler library directory Step 6 If you do not have the tcl8 4 tk8 4 library installed on your Linux OS you may need to install the correct version that Microcross ships on the GX L
15. cr S make load cr If you have any load errors make sure your target IP address TGTIP variable is correctly assigned in the Makefile build directory GX Linux User Guide E 35 Section 5 Making Modifications to GX Linux 5 2 Modifying GX Linux Professional Platform 5 2 1 GX Linux BSP Components The software downloaded to the target hardware is comprised of various components listed below e Bootloader UMON e Linux kernel Linux e Target file system The target file system itself consists of various components e Linux file system framework including uClibc libraries e Development applications Busybox tinylogin tftp etc e Loadable kernel modules e Other applications 5 2 2 Building All of the Components All of the GX Linux BSP components can be built using the following commands S cd lt build directory gt cr S make all cr Makes zlmage 1 2Mb romfs img 1 7Mb and startlinux 1 3 kb size will vary as apps apply 5 2 3 Building All Components Excluding Examples All of the examples can be built using the following commands 2 0 xsDuidd direclory gt cr S make distclean cr S make config system The above step builds everything To add your own example applications after building the system follow the procedure below Building Your Own Applications 5 2 4 Building Your Own Applications We assume you already performed at least a preliminary build of the kernel library and root
16. documentation GX Linux BSP binaries with example programs and boot ROM recovery files for the Cogent uSBC Go through the installation and initial setup procedures in the next section and then go to Section 3 to get started e Cogent uUSBC OEM board and breakout board with power supply null modem serial cable and cross over Ethernet cable GNU X Tools Linux toolsuite and ELF toolsuite UMON bootloader and GX Linux startup script startlinux Linux kernel v2 6 x binary for the target processor pre built uClibc Library pre built a small C library for Embedded Linux users Busybox ona ROM filesystem with basic system utilities and example applications pre built GX Linux Standard Makefile for building examples applications and filesystem GX Linux User Guide E 7 Section 1 Overview 1 3 Components of the GX Linux Professional Platform The GX Linux Professional Platform package includes a compact disk CD ROM loaded with GNU X Tools documentation GX Linux BSP sources build scripts with example programs and boot ROM recovery files for the Cogent uSBC plus a second CD ROM with Visual X Tools IDE Consult Visual X Tools User Guide for installation instructions Go through the installation and initial setup procedures in the next section and then go to Section 3 to get started e Cogent uSBC OEM board and breakout board with power supply null modem serial cable and Ethernet cable GNU X Tools Linux toolsuite and ELF toolsuite
17. graphical front end invoke it using the following command ddd debugger lt target alias gt gdb cr If using a network GDB connection enter the commands below cd lt build directory gt examples hello x cr S lt target alias gt gdb cr gdb set endian little cr gdb target remote x x x x 2001 cr gdb add symbol file hello x cr Where The string x x x x is replaced with the actual IP address of the target hardware If you are not sure what the IP is type ifconfig on the target hardware command line to generate a network configuration report The port 2001 was selected randomly as a high port number It must match the port number that was provided on the preceding target hardware gdbserver command If using a serial connection to the gdbserver enter the commands below S cd lt build directory gt examples hello x cr S lt target alias gt gdb Gr gdb set endian little cr gdb set remotebaud 38400 cr gdb target remote dev ttyS1l cr gdb add symbol file hello x cr By default most Linux workstation s serial ports start up at 9600 baud On the target hardware dev ttyS1 starts up at 9600 baud See the Changing Serial Port Settings section for GX Linux User Guide E 45 Section 6 Debugging Applications instructions on building the stty command into busybox which will allow you to change the baud rate on dev ttyS1 6 3 Debugging Using the gabinit Using gdbi
18. GX Linux gxlinux You can copy this directory after make all and put it on another machine for mounting to or you can simply make your host system an NFS server and add the path to rootfs in the GX Linux build directory Once the target filesystem is mounted via NFS then applications can be written or modified under this filesystem which is visible after the next power cycle In this scenario the target filesystem is not hosted in the target hardware but rather on a hard drive of a remote Ethernet connected machine typically your Linux development workstation How to Mount Using an NFS Server after Bootup Using the romfs img Issue the following command t mount t nfs o nolock lt ip address gt lt dir to mount gt mnt nfs cr Example mount t nfs o nolock 192 168 0 2 home james gxlinux rootfs mnt nfs cr Ca mnctynis cr ls cr How to Start GX Linux with NFS Mounted Automatically or Manually from the Startlinux Script The developer has a number of options as to how to automate the mount of an NFS server but the most common way with GX Linux is to setup environment variables in UMON to point to the server IP and path and then issue the startlinux command or build an automated script and set it with autoboot with query attributes 1 Add two monrc Environment Variables NFSSERVER and NFSPATH uMON gt set NFSSERVER lt IP ADDRESS gt cr uMON gt set NFSPATH path to rootfs cr
19. GX Linux is uninstalled GX Linux User Guide E 17 Section 3 Getting Started Section 3 0 Getting Started There are two configurations for GX Linux and an optional Application Development Platform comes with both the Standard and Professional Platforms What this means is a developer can build applications on Windows Cygwin using a cross development environment that is identical to the Standard Platform build environment Like the Standard Platform edition the limitation is that you cannot rebuild the kernel and libraries on Windows they are pre built With the Professional Platform however the developer has an option to build all modify kernel and libraries and then rebuild on a Linux host Then the developer may overlay the pre built kernel and modified libraries onto the Windows Cygwin environment and proceed to build applications in that environment This option does not prevent the developer however from performing all tasks including application development on a Linux host which he she many prefer to do Below are the names of the appropriate sections for getting started with your Platform version Section 3 4 summarizes useful commands and tips using MicroMonitor Boot ROM Section 3 1 Getting Started with the Standard Platform on Linux Host Section 3 2 Getting Started with the Professional Platform on Linux Host Section 3 3 Getting Started with Application Development Setup on Windows Host Section 3 4 MicroMonitor B
20. Platform are shown in Table 2 5 Table 2 5 Professional Platform Build Directory Directory File Description of gxlinux Professional Platform Build directory Name Directory of BusyBox utilities Default Linux target configuration files Directory of 22 example applications that are built and copied into the root filesystem usr bin Directory of the kernel source tree varetc Directory contains the filesystem etc and var directory contents the etc directory contains aa the system configuration files for the host and the var directory contains logs lock files and process specific data files Table 2 6 shows the source directory contents with all of the source files come with GX Linux The only file that is needed to install however is gxlinux lt ver gt lt csbxxx gt bin tar gz and the next step shows how to install this tarfile Table 2 6 Source Directory src on CD ROM Source File Name Tar file contains the BusyBox source tree Tar file contains all of the configuration files for the BSP examples tar gz Tar file contains 20 example programs that get built and added to usr bin dir in the ROM filesystem Tar file of the Kernel source tree Tar file of the root filesystem uClibc lt ver gt tar gz Tar file of uClibc static and shared runtime libraries Tar file of filesystem elements that include the etc and var dirs Step 8 GX Linux Professional Platform BSP with Build
21. Put small initialized non const global and static data in the sdata section which is pointed to by register r13 Put small uninitialized global and static data in the sbss section which is adjacent to the sdata section The msdata eabi option is incompatible with the mrelocatable option The msdata eabi option also sets the memb option msdata sysv On System V 4 and embedded PowerPC systems put small global and static data in the sdata section which is pointed to by register r13 Put small uninitialized global and static data in the sbss section which is adjacent to the sdata section The msdata sysv option is incompatible with the mrelocatable option msdata detault On System V 4 and embedded PowerPC systems if meabi msdata is used compile code the same as msdata eabi otherwise compile code the same as msdata sysv msdata none On embedded PowerPC systems put all initialized global and mno sdata static data in the data section and all uninitialized data in the bss section On embedded PowerPC systems put global and static items less than or equal to num bytes into the small data or bss sections instead of the normal data or bss section By default num is 8 The G num switch is also passed to the linker All modules should be compiled with the same G num value mregnames On System V 4 and embedded Po
22. ROM image for the romfs img filesystem by issuing the following commands S cd home gxlinux cr S make all Gr builds example applications installs them and re generates a ROM filesystem Step 5 Load Binaries and Startup Script This step assumes that the target board is powered up connected to Ethernet and uMON prompt is displayed in a serial terminal From the GNU X Tools Shell and assuming you are still in the build directory issue the following command that will load the GX Linux binaries and startup script we also assume you assigned the target board an IP address and edited the makefile to add this IP address S make load cr Three images should start loading onto the board see the serial terminal interface for upload response in MicroMonitor The images loaded are as follows 1 zImage kernel 2 romfs img ROM root filesystem and 3 startlinux startup script Step 6 Reset and Boot Linux Press the board reset switch once the files have completely transferred From the serial terminal window issue the following command uMON gt startlinux cr this script calls the Linux kernel and filesystem to execute The Linux kernel should uncompress and mount a ROM filesystem If there are any errors reset the board and repeat this step Occasionally the kernel aborts on a bootup due to a corrupted flash file system Follow steps in the MicroMonitor tips section to issue a command uMON gt t
23. TK version by issuing the following commands from an xterm Bash shell S telsh Gr info tclver cr version is echoed back exit cr o0 If you need to install the right version of TCL TK the following is the command to issue to install the library from Microcross CD ROM login as su or root if not already done so xtools install share gdbtcl cr exit cr You should now be logged out of su root Note if you had any errors in the last step due to xtools command script not finding the proper mount path then simply add the path after share gdbtcl e g xtools install share gdbtcl mnt cdrom bin Step 7 Select or create an install directory on your Linux host machine preferably in your home lt user name gt directory or a directory where you have full permissions We call this the install directory because the build directory will be untarred to this directory The build directory is named gxlinux and when you untar the GX GX Linux User Guide E 11 Section 2 Installation and Setup Linux BSP tarfile it creates this build directory at the point of install The Build contents for GX Linux Standard Platform are shown in Table 2 2 Table 2 2 Standard Platform Build Directory Directory File Description of gxlinux Standard Platform Build directory Name Default Linux target board configuration files Directory of 22 example applications that are built and co
24. another derived file gxlinux linux include linux autoconf h is created The autoconf h file is included by most kernel source files to control which features are built 5 3 2 Changing the Working Configuration Changing the GX Linux kernel configuration requires changing the config working copy It should not be modified directly but rather it should modify it using the steps below In this procedure we use make ARCH lt arch gt xconfig to modify config Note We assume that you have the QT components from the KDE development package installed before using xconfig 1 Type the commands below to initiate xconfig S ead lt 0 dd directory linux cr S make ARCH lt arch gt menuconfig cr Or alternatively make ARCH lt arch gt xconfig cr Note ARCH can equal arm mips ppc etc 2 The menuconfig xconfig will display all of the kernel options and their current settings Menuconfig xconfig will allow you to change any kernel setting Be sure to save your changes before you exit from xconfig cd lt build directory gt cr S make SaveCfg cr saves the config file to the master config file in config csbxxx kernel conf directory 3 With the menuconfig xconfig session complete you can build the new GX Linux kernel as follows assuming arm for purposes of this example S Co lt build directory gt 1inux cr GX Linux User Guide E 37 Section 5 Making Modifications to
25. assumes that the target board is powered up connected to Ethernet and uMON prompt is displayed in a serial terminal From the build directory in xterm Bash issue a make command that will load the GX Linux binaries and startup script we assume you assigned the target board an IP address and edited the makefile connections are made and the board is powered on S make load cr Three images should start loading onto the board see the serial terminal interface for upload response in MicroMonitor The images loaded are as follows 1 zImage kernel 2 romfs img ROM root filesystem and 3 startlinux startup script Step 6 Reset and Boot Linux Press the board reset switch once the files have completely transferred From the serial terminal window issue the following command uMON gt startlinux cr this script calls the Linux kernel and filesystem to execute The Linux kernel should uncompress and mount a ROM filesystem If there are any errors reset the board and repeat this step Occasionally the kernel aborts on a bootup due to a corrupted flash file system Follow steps in the MicroMonitor tips section to issue a command uMON gt tfs clean to defrag the flash file system The Linux startup script is set with a Tiny Filesystem attribute that makes startlinux an executable like a batch file in DOS To change this attribute so that you can automatically boot with query into Linux with a query to stop a
26. cr 12 m GX Linux User Guide Section 2 Installation and Setup Note You might need to substitute the right path to the CD ROM if your system differs from the standard CD ROM mount pathing The build directory gets created at the point you install the GX Linux BSP and is named Sox lanux Step 9 At this point the BSP and toolsuite are installed Next go to Section 3 to configure the target board serial interface network settings and then run GX Linux and run example applications on the Cogent uSBC 2 2 Professional Platform Installation and Setup on a Linux Host Workstation The installation procedure for the Professional Platform is a command line procedure and is simple and straightforward We assume that all requirements in Section 1 are met and that you have a Linux OS running on your workstation or server before getting started with this installation All commands are done from the Bash xterm shell in Linux Step1 Insert the GX Linux distribution CD into your host computer s CD ROM drive Step 2 Start a Bash xterm shell and login as root or use su You will need to do this each time you install or uninstall GNU X Tools toolsuite because you will need write access to the usr bin and usr lib directories where the toolsuite is installed Step 3 Mount the GX Linux distribution CD on the CD ROM drive using the mount command Example mount t iso9660 dev cdrom mnt cdrom cr The sys
27. directory Browse the CD ROM src directory to get the complete filename format is gxlinux lt ver gt lt csbxxx gt lt date gt tar gz GX Linux User Guide E 15 Section 2 Installation and Setup Example with notional names Installing GX Linux BSP e Open an xterm Bash shell e Mount the GX Linux CD ROM if it is not already mounted e Issue the following commands to create a build directory S cd home lt user name gt cr other other install directory tar SvVzZe 7mnl Cdrom src qx linux 1 0e csbo37 20051015 tar gz cr Note You might need to substitute the right path to the CD ROM if your system differs from the standard CD ROM mount pathing The build directory gets created at the point you install the GX Linux BSP and is named aie p cilligs I gue aaa Step 9 Now you need to set your user permissions on the host Linux operating system so you can write to usr lt target alias lib and usr lt target alias gt include directories Ask your system administrator to add you to the bin users and wheel groups An example for Red Hat v9 0 follows Example Click on Start System Settings Users and Groups Enter your root password Double click on the username that you wish to add permissions The User Permissions dialog box pops up Click on the Groups tab and select the bin users and wheel groups check boxes and click OK Click on File
28. function calls via function pointers msingle pic base Treat the register used for PIC addressing as read only rather than loading it in the prologue for each function The run time system is responsible for initializing this register with an appropriate value before execution begins mpic Specify the register to be used for PIC addressing The default is register lt reg gt r10 unless stack checking is enabled when r9 is used Must be used with fpic option to be valid mpoke function Write the name of each function into the text section directly name preceding the function prologue The generated code is similar to this tO ascii arm _poke_function_name 0 align t1 word Oxff000000 t1 tO arm_poke_function_name mov ip sp stmfd spl fp ip Ir pc sub fp ip 4 When performing a stack backtrace code can inspect the value of pc stored at fp O If the trace function then looks at location pc 12 and the top 8 bits are set then we know that there is a function name embedded immediately preceding this location and has length pc 3 amp OxffOO0000 GX Linux User Guide E 79 Appendix 1 GNU X Tools ARM Linux Toolsuite Compiler Defined Symbols and Standard Search Directories From the command line in GNU X Tools Shell type S xtools arm linux cr arm linuxs coc y E cr You will get all of the compiler defined symbols printed out on the screen Press Ctr1 c to exit this mode Assembl
29. gt code section data an initialized data section and bss an uninitialized data section These sections have default flags and the linker understands the default names similar directive to the armasm GX Linux User Guide E 81 Appendix 1 GNU X Tools ARM Linux Toolsuite GNU Assembler Directive directive AREA The following are allowable section flags for ELF format files lt Flag gt Meaning a allowable section W writable section X executable section Set lt variable name gt This directive sets the value of a variable It is similar to SETA in tale Reserves the given number of bytes The bytes are filled with zero or lt fill byte gt lt fill_ byte gt if specified similar to SPACE in armasm Inserts a list of 32 bit word values as data into the assembly similar to DCD in armasm Assembler Special Characters Syntax Inline comment char Line comment char Statement separator 7 Immediate operand prefix ae ort Register Names General registers Sr0 r15 0 const 0 FP registers SEQ SET Non saved temp regs 3r0 r3 Sr12 Saved registers Sr4 r10 Stack ptr register Ssp Frame ptr register Sfp Link retn register Slr Program counter Sip Status register Spsw Status register flags xPSR x C current xPSR all x S saved XPSR xPSR X xPSR ctl xPSR fs xPSR fx xPSR fc xPSR cs xPSR cf xPSR cx and so on Arm Procedure Call Standard APCS C
30. program strip has the same effect X Remove all local symbols from the output file Global symbols subprograms and common block names remain in the output file This reduces the object file s size Ignored unless s is specified n GX Linux User Guide E 71 Section 9 How to Use GNU X Tools Make the text segment read only Create an object file that can be included in further linking runs i e further passes through 1d Among other things this inhibits Undefined symbol messages because the symbols may be defined in a later 1d pass and prevents 1d from creating common storage immediately If you wish to create common storage at this time use the d option also e name Use the symbol name as the entry point to the executable program By default the entry point is the beginning of the first object module The Gcc automatically links your object files with a run time initialization module usr lib crt0 o that starts your program and provides its initial entry point If you run the linker separately you must either put usr lib crt0 o at the start of your object files or provide your own entry point M Produce a load map that shows where each function is located in the resulting object file where each section begins and ends and what the value of each global symbol is This option is usually used with ccc as follows W1 M lt mapfile name gt where lt mapfile name gt can b
31. run and test applications using a familiar Windows environment If you have the capacity to rebuild the kernel to add custom settings and drivers the do so on a Linux host machine and copy the image it may be called zImage or vmlinux Next go to Section 3 to configure the target board serial interface network settings and then run GX Linux and example applications on the Cogent uSBC 2 4 Uninstall GX Linux Linux Host To remove a previously installed version of the GX Linux BSP software issue the following command WARNING Before removing the tree be sure to backup any files you want to keep S od lt peer dir to gxlinuk gt cr gt im ri Gxlanux cr Windows Host To uninstall the Application Development Platform click on the Start Control Panel and select Add Remove Programs Select Remove Cygwin with GX Linux Platform Manually delete the Cygwin directory 2 5 Uninstall GNU X Tools Toolsuite If at any time you need to uninstall GNU X Tools GX Linux Toolsuite follow the two steps below 1 Start xterm Bash shell and login as su or root 2 Issue the command xtools remove lt target alias gt Target aliases for GNU X Tools GX Linux Toolsuites include arm linux mips linux mipsel linux ppc linux arm elf mips elf etc Note that on a Windows host workstation the developer uninstalls the GNU X Tools on Cygwin at the same time as
32. searched for using the B prefix if needed specs file Process file after the compiler reads in the standard specs file in order to override the defaults that the gcc driver program uses when determining what switches to pass to ccl cclplus as 1d etc More than one specs file can be specified on the command line and they are processed in order from left to right 9 7 5 Debugging and Profiling Options These options request the compiler to create additional code and an expanded symbol table for the various profilers and debuggers dbx prof gprof and the branch count profiler They are extremely helpful for debugging and tuning code under development but should not be used for production release versions of your program pP Link the program for profiling with prof When you execute a program compiled with this option it produces a file named mon out that contains program execution statistics The profiler prof reads this file and produces a table describing your program s execution pg Link the program for profiling with gorof Executing a program compiled with this option produces a file named gmon out that includes execution statistics The profiler gorof reads this file and produces detailed information about your program s execution For example the following command compiles the file program f generating code for profiling with gprof lt target alias gt
33. settings The settings shown are notional and are for reference of the procedure only Use the UMON command line interface in your serial terminal session to enter these commands uMON gt set c uMON gt set IPADD 192 168 0 110 IP address uMON gt set NETMASK 255 255 255 0 network mask uMON gt set GIPADD 192 168 0 250 gateway IP address uMON gt set f monrcec uMON gt reset DHCP BOOTP network settings Follow this example and enter the commands using your serial terminal UMON command line interface uMON gt set c uMON gt set IPADD DHCP or DHCPv or DHCPV or BOOTP uMON gt set f monrc uMON gt reset Select only one for IPADD setting DHCP No verbosity enabled DHCPv Limited verbosity enabled DHCPV Extreme verbosity enabled BOOTP Runs BootP IMPORTANT After configuring the network settings and initiating the reset command the target board will re boot MicroMonitor Notice that in the serial terminal interface that the new IP address is displayed if the new IP address does not show up on the display go back to the previous make the necessary corrections to monrc IMPORTANT When using DHCP BootP the new IP address should be annotated in your notes because you will need this IP address for loading GX Linux files via TFTP If your DHCP BootP server assigns a different IP address every time you reboot MicroMonitor you may want to consider manually setting the network IP address while in the development phase of your
34. standard system directories for header files Thus I and nostdinc are independent Ldir Add directory dir to the list of directories to be searched for 1 64 E GX Linux User Guide Section 9 How to Use GNU X Tools Bprefix This option specifies where to find the executables libraries include files and data files of the compiler itself The compiler driver program runs one or more of the subprograms cpp ccl as and 1d It tries prefix as a prefix for each program it tries to run both with and without machine version For each subprogram to be run the compiler driver first tries the B prefix if any If the name is not found or if B was not specified the driver tries two standard prefixes which are usr lib gcc lib and usr local lib gcec lib If neither of those results in a file name that is found the unmodified program name is searched for using the directories specified in your PATH environment variable B prefixes that effectively specify directory names also apply to libraries in the linker because the compiler translates these options into L options for the linker They also apply to includes files in the preprocessor because the compiler translates these options into isystem options for the preprocessor In this case the compiler appends include to the prefix The run time support library file libgcc a can also be
35. the file it creates This file GX Linux User Guide E 69 Section 9 How to Use GNU X Tools OOO Fo ale dependencies of the main source file obj file Name the object file output from as obj file By default it has the name a out or b out for Intel 960 targets only You use this option which takes exactly one filename to give the object file a different name PRO Fold the data section into the text section statistics Print the maximum space in bytes and total time in seconds used by assembly W ttt Suppress waring messages sd we ignore pee ignore O Zz Generate an object file even after errors O O Standard input or source files files to assemble This option is accepted for script compatibility with calls to other assemblers 9 9 Using the Linker strip local absolute Remove local absolute symbols from the outgoing symbol table Print the as version Print the as version and exit The 1d linker combines several object modules and libraries into a single executable file It resolves references to external variables external procedures and libraries creating a complete self sufficient program You never need to invoke 1d explicitly In most cases it is simpler to use the GCC command to link files even if you do not have any source files to compile The Gcc guarantees that certain libraries will be present in the proper order even if they are not listed on the comma
36. to Use GNU X ToOOIS ccccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeesessessensensensensenseneeaeeaesaesaes 51 91 UME UG OA cece cts cress ccc Scien a ee etce ec ccs ges cre enschede sateen ncn eda meme deca ana ne an iaei 51 9 2 Using the GNU X Tools Command Line Tool XtCO01S ecceecccececcceccseeeeeeeeeeeeeeeeeeeseeeeeeseeeeessaeeeeeseeeeeesaaeeeneas 51 9 3 Invoking GNU K TOONS vrcseidonscncscenscielawncdissiamanenindaisvmatadantusind ddpwetilenawnndaniaunndbwtennceidvanwstiiernwacdauwebondindeuneciavenustidebaweeds 52 9 4 Using the GNU X TOools Toolsuite ccccccccececceesscecseseeecsaeeeceeseecseuseeecsaeeecseaseeessageessageeeesseseesssaseeessagenes 53 GX Linux User Guide E v os ee 0 E E EE 100 6 gt ene ee E A E E EA E ee oe ee rene ee eee 53 9 4 2 GNU X Tools Toolsuite Description 2 0 0 0 cece ccecccceeeeeceeeeeeeeceseeeeseeeessaeessaeeeseaeeeseaseseueessauseeseaeeesensessags 54 94 Control Programi OGC J suunnassa aenn aeaa aana DEN aa dun ESEN nina Eaha TaS GEENEEN SEEE RERAN E an 55 9 5 Controlling the Tools Using the GCC icccccecccceceeceeeaeeeeeeeeeeeesaeeeeeeaeeeeeeeeeeeeseaeeeessaaseeeseaueeeesseeeeesneeeeesaaees 58 9 5 1 GCC Options Commonly Used cee ccccecccccseeeeeeeeeeeeeeeeeeeeeee cesses eeeesseeeeeseeeeeseeeeeeeseeseeeseeeeeeesaeeeeesaeeeeeeas 59 9 6 Controlling Linker FOM GCC tare cases eeranteo enentecaamnseiannceeelae EET aA E AEEA EE AAE TEE EE Ei 61 9 7 Compilaton OU ONS css a e Eaa E a wad
37. uMON gt set f monrc cr m uMON gt reset cr 2 Manually Start Linux from Serial Terminal uMON gt startlinux nfs SNFSSERVER SNFSPATH cr 3 Autostart Linux from uMON Bootup uMON gt edit feB startlinuxnfs cr uMON gt i cr uMON gt startlinux nfs SNFSSERVER SNFSPATH cr m uMON gt cr uMON gt q cr uMON gt reset cr autostarts with query into linux with NFS mount reboot reboot from Linux to query UMON hit any key to stop Linux boot 4 Modify Autostart File Attributes to Manual Start Attribute with TFS Copy Command uMON gt tfs fe cp startlinuxnfs startlinuxnfs cr the fe gives the file an attribute for executing a script m uMON gt reset cr uMON gt startlinuxnfs cr start Linux nfs mode manually The procedure in 3 and 4 above can be done also for a startlinux without NFS simply omit nfs SNFSSERVER SNFSPATH from the command line in the Autostart procedure If there are any errors consult your system administrator for help or manually modify startlinux in the config S BOARD directory on the host workstation to hard code your NFS settings NFSSERVER and NFSPATH reload the script into the UMON TFS tiny file system and then issue the command in step 2 above 40 E GX Linux User Guide Section 5 Making Modifications to GX Linux 5 6 3 Writing to On Board Flash via a Pendrive USB Some Linux applications will require the ability to store data persiste
38. way to get your own application on the target board is to copy your application named with a x file extension into the examples directory which is under the build directory and issue the following command in the xterm Bash shell S make install apps romfs cr make load cr reload your images to the target board After uploading three files to the target board startlinux zimage and romfs img you can manually start GX Linux by issuing the following commands cx get a command prompt after upload reset cr get the board in a refresh state S Startlinux cr Linux boots to a user prompt On the target board in the usr bin directory are a dozen example programs that can be run from the Minicom interface Issue the following commands cd usr bin cr 1s cr You can see all examples they have a x file extension on them To run each example issue the by name command double x cr float x cr hello x cr etc Step 9 Useful Linux Commands cat proc cpuinfo Show information such as bogomips architecture and manufacture information reboot Reboots system into UMON 22 E GX Linux User Guide Section 3 Getting Started 3 2 Getting Started with the Professional Platform on Linux Host Board Connection and Initial GX Linux Bootup Make physical connections per the diagram layout in Figure 3 2 If connecting to a hub on a network disregard connecti
39. 1 c to exit this mode Assembler Machine Dependent Options Options _ Description S O mppc mppc32 m403 m603 Generate code for Motorola PowerPC 603 604 m604 Option is preserved for backwards compatibility with older makefiles and tools Do not allow symbolic names for registers Assembler Special Characters Syntax Inline comment char E os Line comment char Statement separator Register Names General registers r0 r31 GX Linux User Guide E 99 Appendix 3 GNU X Tools PowerPC Linux Toolsuite FP registers f0 Si 31 Stack ptr register Ssp alias for ri Frame ptr register Sfp Link retn register Slr Program counter Spc Status register sero Ser7 Count register GOCI Small data pointer r13 C Calling Conventions Parameter pl p8 oto ar10 Return value vlv r3 r4 FP parameters pl pg fpl Sfp8 FP return value v1 Sfpl Saved regs r14 r31 6 14 Sf 31 Addressing Modes rn in the following refers to any of the numbered registers but not the control registers The memory layout is big endian addr Absolute addressing mode rn Register direct rn Register indirect also called register based OFf in Register based with offset Register based with register offset value Immediate data context sensitive most instructions end in i Machine Dependent Directives rodata Allocate data to read only data section Opcodes For detailed informat
40. 3 Load startlinux for autoboot without abort query warning there is no way to recover an error without disaster recovery efforts using a JTAG emulator to reload MicroMonitor into RAM and then write back to flash S cd lt build dir gt boot S ttftp lt target ftp address gt put startlinux startlinux eb Change startlinux Attribute Options There is another option to change startlinux script flags without having to reload startlinux again by using the serial UMON command line interface Microcross startlinux is preloaded with the e flag attribute set which is the manual boot up setting Two other boot options are available and can be set issuing one of the following commands 1 Autoboot with abort query case sensitive uMON gt tfs feB cp startlinux startlinux 2 Autoboot without abort query case sensitive WARNING there is no way to recover from an error without disaster recovery efforts using a JTAG emulator to reload MicroMonitor into RAM and then write back to flash UMON gt Cis feb co starclinux startlinux GX Linux User Guide E 31 Section 3 Getting Started MicroMonitor training material is available by Microcross Here is a link to more information documentation http www microcross com html micromonitor html Also there is a MicroMonitor User Manual in the Cygwin doc directory and the CD ROM doc directory Reload zimage Procedure Similarly to the u
41. 32 x 32 Bit ADDR SPACE 32 Bit 4 GB Flat or VM APPROX INSTRUCTION THROUGHPUT Up to 4 instructions per cycle some variants branch prediction PIPELINED FP INSTRUCTIONS IEEE 754 FPU some variants Variants include 4xx 5XX 6xx e TXX T4xx VARIANTS 8XX 9xx Rios Rios1 Rios2 Rsc G3 G4 Gd This toolsuite comprises a complete development environment ATTRIBUTES for the PowerPC processor family It is widely supported has a scalable architecture and has many on chip peripherals available The PowerPC Toolsuite consists of the following tools ppc linux as GNU assembler as 2 15 ppc linux ld GNU linker Id ppc linux addr2line Converts addresses to file names amp line ppc linux ar Creates object code archives ppc linux gcov Test coverage program for analysis ppe linux im Lists symbols from object files ppc linux obj copy Copies and translates object files ppc linux obj dump Displays information from object files ppe linux ranlib Generates index to archive contents ppc linux readelf Displays information about ELF objects ppc linux size Lists file section sizes and total sizes ppe linux strings Lists printable strings from files ppc linux strip Strips debug symbols from binaries poc linux gdb GDB oe ppc linux gdbtk Visual PoR gal uClibc C and Math Libraries 0 9 26 92 m GX Linux User Guide Appendix 3 GNU X Tools PowerPC Linux Toolsuite TARGET CPU DEPENDENT INFORMATION This to
42. 54 Basic 32 bit version includes support for r2k r3k r4k VARIANTS 5k r6k r8k variants from multiple sources ATTRIBUTES Widely used in telecom network applications Very wide range of variants and multi vendor support REFERENCES www mips com publications index html The MIPS Toolsuite consists of the following tools mips linux as GNU assembler as 2 15 mips linux ld GNU linker Id mips linux addr21line Converts addresses to file names amp line mips Lainux ar Creates object code archives mips linux gcov Test coverage program for analysis mips linux nm Lists symbols from object files mips linux objcopy Copies and translates object files mips linux objdump Displays information from object files mips linux ranlib Generates index to archive contents mips linux readelf Displays information about ELF objects mips linux size Lists file section sizes and total sizes mips linux strings Lists printable strings from files mips linux strip Strips debug symbols from binaries mips linux gdb GDB debugger 6 1 mips linux gdbtk Visual GDB uClibc C and Math Libraries 0 9 26 84 m GX Linux User Guide Appendix 2 GNU X Tools MIPS Linux Toolsuite TARGET CPU DEPENDENT INFORMATION This toolsuite comprises a complete development environment for the MIPS32 processor family Included in this section of the Appendix are the required compiler and linker flags a list of debugger targets for both command line GDB and Visual GDB
43. D defsym sym value f gstabs help I dir J K JLL keep locals o objfile R statistics as oo ae v version version W w x Z __ mbig endian mlittle endian if implemented __ mfpa10 mfpa11 mfpe old mno fpu if implemented EB EL ifimplemented o O i an ooo i EB EL if implemented O n N b no relax nocpp G num mcpu CPU if implemented T trap break o trap break _ emulation name files These assembler switch options are discussed in depth within the manual MC Utilities pdf docs directory on GNU X Tools CD ROM and in Cygwin docs In addition each assembler has target specific switch options The target specific switch options are located in the Appendices of this User Guide Unlike older assemblers as is designed to assemble a source program in one pass of the source file This has a subtle impact on the org directive These options enable listing output from the assembler By itself a requests high level assembly and symbols listing You can use other letters to select specific options for the list ah requests a high level language listing al requests an output program assembly listing and as requests a symbol table listing High level listings require that a compiler debugging option like g be
44. DC Power Target Board P S AC Power You have two options to setup the network file monrc in MicroMonitor manual settings or DHCP BootP Consult your system administrator if you need help in determining your network settings GX Linux User Guide E 19 Section 3 Getting Started Manual network settings The settings shown are notional and are for reference of the procedure only Use the UMON command line interface in your serial terminal session to enter these commands uMON gt set c uMON gt set IPADD 192 168 0 110 IP address uMON gt set NETMASK 255 255 255 0 network mask uMON gt set GIPADD 192 168 0 250 gateway IP address uMON gt set f monrcec uMON gt reset DHCP BOOTP network settings Follow this example and enter the commands using your serial terminal UMON command line interface uMON gt set c uMON gt set IPADD DHCP or DHCPv or DHCPV or BOOTP uMON gt set f monrc uMON gt reset Select only one for IPADD setting DHCP No verbosity enabled DHCPv Limited verbosity enabled DHCPV Extreme verbosity enabled BOOTP Runs BootP IMPORTANT After configuring the network settings and initiating the reset command the target board will re boot MicroMonitor Notice that in the serial terminal interface that the new IP address is displayed if the new IP address does not show up on the display go back to the previous make the necessary corrections to monrc IMPORTANT When using DHCP BootP the new IP a
45. GX Linux S make ARCH arm CROSS COMPILE arm linux mrproper Cr S make ARCH arm CROSS COMPILE arm linux vmlinux cr If the build is successful the resulting kernel image can be found in the Linux directory lt buld directory gt linux vmlinux an ELF object format Now you can use the master configuration and build system with confidence that the kernel will build 5 3 3 Resetting the Kernel to the Default Configuration Should you want to return to the GX Linux default settings you can accomplish this with the steps below assuming the ARM in this example S CO Dario G1 rectory cr S make distclean cr S cd linux cr S make ARCH arm CROSS COMPILE arm linux mrproper cr ep arch lt arm or other gt contigs lt csbxxx detcontig gt config cr S make ARCH arm CROSS COMPILILES Yrm linux oldcontig er S make ARCH arm CROSS COMPILE arm linux vmlinux cr S CO pi cr make SaveCfg cr 5 3 4 Customizing the Kernel Configuration If you find that your particular needs cannot be met using the available kernel configuration options you may want to modify the make xconfig scripts that control the configuration session The particular file that controls the xconfig program presented above is at a a Oxlanux lanux arch arm contig 1n 5 4 Changing the Target File System The directory structure under gxlinux rootfs is the master file system structure used to create the target file system Files can be i
46. Quit to exit At this point the BSP and toolsuite are installed and permissions are set Next go to Section 3 to configure the target board serial interface network settings and then run GX Linux and example applications on the Cogent USBC 2 3 Application Development Setup on Windows Host Available for Standard and Professional Platforms The Application Development Platform is provided for Windows users who want to create their Linux applications in a more familiar environment on Windows using Cygwin and Visual X Tools The limitation is that you will not be able to re build the kernel or uClibc on Windows Cygwin host however combined with the Professional Platform the user can recreate the kernel and custom libraries and copy them into the GX Linux environment on Windows Cygwin Files in the win directory on the GX Linux CD ROM include Ox0409 ini Autorun inf Cygwin with GX Linux Platform CSBxxx msi Data1 cab instmsia exe instmsiw exe setup exe Setup utility to install Cygwin amp GX Linux Application Setup on Windows setup ini Open Explorer and navigate to the win directory on the GX Linux CD ROM and execute setup Follow the on screen instructions to complete the installation The installation will take approximately 20 minutes or more 16 E GX Linux User Guide Section 2 Installation and Setup depending on the speed of your computer Cygwin is a Linux Unix platform itself so users can build
47. SC Machines alias arm linux l Multiple Manufacturers ARM Atmel Freescale Intel NetSilicon MFR af Philips Samsung Sharp and many others CPU TYPE RISC Von Neumann 32 Bit Fixed Instructions 16 Bit Thumb mode GP REGS SIZE 16 32 Bit ADDR SPACE 64MB Linear Endian Selectable CYCLE RATE Core Dependent APPROX INSTRUCTION THROUGHPUT PIPELINED INSTRUCTIONS 11 TYPES ADDR MODES 5 Load Store FP INSTRUCTIONS None INTERRUPTS 8 Exceptions 2 External Interrupts normal fast Depends on core variant VARIANTS ARM 2 250 3 6 60 600 6 10 620 ARM 7 7m 7d 7dm 7di 7dmi 70 700 700i 7 10 7 1xxc 75xxfe 7tdmi ARM 8 810 9 9e 920 920t 940t 9tdmi Architectures armv2 armv2a armv3 armv3m armv4 armv4t armv5 armv5t armv5te Based on current independent studies the ARM is the most popular RISC processor for embedded applications Its architectural specification is highly scalable and a number of ATTRIBUTES variants have been defined and produced by several l manufacturers As a result a wide range of configurations and performance levels exist giving embedded designers many flexible design options The simple instruction set architecture is easy to learn yet powerful and optimized for compilers 76 E GX Linux User Guide Appendix 1 GNU X Tools ARM Linux Toolsuite The ARM Toolsuite consists of the following tools Tool Description GNU Compiler Collection GCC arm linux as GNU assembler a
48. Section 2 4 Uninstall GX Linux Section 2 5 Uninstall GNU X Tools Toolsuite Note Wherever you see cr it means Carriage Return i e Enter on the keyboard GX Linux User Guide E 9 Section 2 Installation and Setup 2 1 Standard Platform Installation and Setup on a Linux Host Workstation The installation procedure for the Standard Platform is a command line procedure and is simple and straightforward We assume that all requirements in Section 1 are met and that you have a Linux OS running on your workstation or server before getting started with this installation All commands are done from the Bash xterm Shell in Linux Step1 Insert the GX Linux distribution CD into your host computer s CD ROM drive Step 2 Start a Bash xterm shell and login as root or use su You will need to do this each time you install or uninstall GNU X Tools toolsuite because you will need write access to the usr bin and usr lib directories where the toolsuite is installed Step 3 Mount the GX Linux distribution CD on the CD ROM drive using the mount command Example mount t iso9660 dev cdrom mnt cdrom cr The system will announce that it has mounted the CD ROM as read only Note On some Linux systems the CD ROM will be mounted by an automounter which means using mount in step 3 is not required or the procedure may need to be modified to accommodate non standard Linux distributions or a machine wit
49. Setup uMON You have two options to setup the network file monrc in MicroMonitor manual settings or DHCP BootP Consult your system administrator if you need help in determining your network settings Manual network settings The settings shown are notional and are for reference of the procedure only Consult your network administrator if you do not understand how to setup network settings for your network Use the UMON command line interface in your serial terminal session to enter these commands with your substituted settings uMON gt set c uMON gt set IPADD 192 168 0 110 IP address uMON gt set NETMASK 255 255 255 0 network mask uMON gt set GIPADD 192 168 0 250 gateway IP address uMON gt set f monrcec uMON gt reset DHCP BOOTP network settings Follow this example and enter the commands using your serial terminal UMON command line interface uMON gt set c uMON gt set IPADD DHCP or DHCPv or DHCPV or BOOTP uMON gt set f monre uMON gt reset Select only one for IPADD setting DHCP No verbosity enabled DHCPv Limited verbosity enabled DHCPV Extreme verbosity enabled BOOTP Runs BootP IMPORTANT After configuring the network settings and initiating the reset command the target board will re boot MicroMonitor Notice that in the serial terminal interface that the new IP address is displayed if the new IP address does not show up on the display go back to the previous make the necessary corrections to monrc
50. Use GNU X Tools Note that the ANSI C standard and traditional Kernighan and Ritchie C both define the behavior of the preprocessor either explicitly or implicitly Therefore the options listed below affect both cpp C preprocessor and GCC traditional Supports the traditional C language including lots of questionable but common practices The traditional option also supports all of the FSF s extensions to the C language ansi Supports the ANSI C standard though somewhat loosely The FSF s extensions are recognized except for a few that are incompatible with the ANSI standard Thus ANSI programs compile correctly but the compiler doesn t try too hard to reject non conformant programs or programs using non ANSI features pedantic Issues all the warning messages that are required by the ANSI C standard Forbids the use of all the FSF extensions to the C language and considers the use of such extensions errors As the GCC manual points out pedantic is not a complete check for ANSI conformance it only issues errors that are required by the ANSI standard 9 7 3 Preprocessor Options The following set of options control the cpp preprocessor from the command line M Read the source files figure out which files they include and output lists of dependences for make There is one dependency list for each source file The dependency lists are sent to standard output and compilation doesn t proceed past prep
51. any spaces in the list options in the list are separated by commas Here is an example that is both instructive and useful producing a listing of the assembly language generated together with C source listings To do this we need to pass the alh options to the assembler generate listings of assembly code and high level source we also need to pass the L option to the assembler retain local labels And we need GCC s g option generate additional symbols for debugging the additional symbols tell the assembler where to find the source code The resulting command looks like this lt targer alias gt s gcc c 9 Wa alh b Ssource c cr Listings that include both assembly and source code are interesting from two standpoints You may want to see how your code has been compiled this is instructive whether or not you are optimizing and even if you are not interested in assembly level debugging What is more important though is that you can generate a C assembly listing for optimized code This can be very helpful for debugging under optimization The big problem with debugging optimized code is that there is no longer a simple mapping from your source code into assembly language therefore the debugger cannot single step and perform symbolic debugging With a listing you can find out exactly what the compiler did to your code and get a much better idea of what the code is doing 9 8 Using the GNU Assembler The GNU as
52. ardware s serial port then you can login to the target hardware via the serial port 8 3 3 Standard IO Once logged in over the serial port the system console is automatically mapped to the dev ttyS0O device This means that normal printf statements in a program will route out the serial port Or put generically any GX Linux User Guide E 49 Section 8 Serial Port reference to the system s stdin stdout and stderr device descriptors will map to the dev ttyS0 and therefore the serial port 8 3 4 Restrictions Because dev ttyS0 is the default console applications should NOT use it for other purposes In cases where the board has a second serial port applications can instead use dev ttyS1 8 4 Serial Settings Default Baud Rate By default the target hardware dev ttySO0 serial port starts up at 38400 baud and dev ttyS1 serial port if available or starts up at 9600 baud most Linux workstation s start up at 9600 baud The dev ttyS0 baud rate value of 38400 was chosen to be compatible with the uMON target hardware bootloader A single terminal session such as Minicom can communicate with the bootloader and then with the booted kernel without changing any settings Applications that use a different baud rate can use the standard stty utility or ioctl calls on dev ttyS0 or dev ttyS1 as appropriate for changing serial port speed at runtime The default dev ttyS0 settings a
53. arget alias gt sS ar rs lib lt name gt a list of files cr The option xr indicates that the command ar should add the files named in the list of files to the library named name creating a new library if necessary If a file is mentioned twice in the list of files ar Includes it in the archive twice The s option tells ar to produce an index for the archive this is the function that ranlib would perform If you include the s option whenever you create or modify a library you will not need to use ranlib To update a library use the command lt target alias gt S ar rus lib lt name gt a list of files cr This compares the dates of any listed files with the version of the file in the library If the file in list of files is more recent than the version contained in the library ar substitutes the newer version for the older version The s option updates the library s index To delete one or more files from a library use the command lt target alias gt S ar ds lib lt name gt a list of files cr This option deletes all the files found in list of files To extract one or more files from a library use the command 74 E GX Linux User Guide Section 9 How to Use GNU X Tools lt target alias gt ar x lib lt name gt a list of files cr This does not modify the library file itself It extracts the files named in the list of files from the library regenerating them in the cur
54. ating point constants in the TOC However only 16 384 entries are available in the TOC If you receive a linker error message saying you have overflowed the available TOC space then you can reduce the amount of TOC space used with the mno fp in toc and mno sum in toc options mno fp in toc prevents GCC from putting floating point constants in the TOC and mno sum in toc forces GCC to generate code to calculate the sum of an address and a constant at run time instead of putting that sum into the TOC You may specify one or both of these options Each causes GCC to produce very slightly slower and larger code at the expense of conserving TOC space If you still run out of space in the TOC even when you specify both of these options specify mminimal toc instead This option causes GCC to make only one TOC entry for every file When you specify this option GCC will produce code that is slower and larger but which uses extremely little TOC space You may wish to use this option only on files that contain less frequently executed code malign natural On AIX Darwin and 64 bit PowerPC GNU Linux the malign power option malign natural overrides the ABl defined alignment of larger types such as floating point doubles on their natural size based boundary The option malign power instructs GCC to follow the ABl specified alignment rules GCC defaults to the standard alignment defined in the ABI msoft float Ge
55. ble file system Anything written to the romfs will be lost when the target hardware is powered down Compact Flash SD MMC USB Pendrives and other permanent memory storage devices can be used but GX Linux is not pre configured for any other memory devices You can however create an NFS mounted root filesystem on your network and simply access it using the startlinux script You can also create a filesystem on a USB pendrive and mount it automatically at startup 5 6 2 NFS Mounted Root Filesystem To mount an NFS read write root filesystem you need to have a server setup for NFS mounting The procedures to perform this task are beyond the scope of this User Guide and should be done by a competent Linux system administrator The administrator needs to create the NFS server in a location on your network that you can place your rootfs directory on and have the correct dev directory When you make all two sets of devs get created 1 initial set of pseudodevs for romfs img and 2 final set of devs for rootfs to become a NFS mountable root filesystem The pseudodevs are all prefixed with symbol while the real devs are not Two pieces of information are important to use GX Linux with an NFS mounted filesystem 1 the NFS server IP address and 2 the NFS roofs path on the server Recall that rootfs is part of the build directory in GX Linux User Guide E 39 Section 5 Making Modifications to
56. caches or to not call any such function If called the function must take the same mno fused madd mno flush func arguments as the common _flush_func that is the address of the memory range for which the cache is being flushed the size of the memory range and the number 3 to flush both caches The default depends on the target GCC was configured for but commonly is either _flush_func or __cpu_flush mbranch likely Enable or disable use of Branch Likely instructions regardless of the default for the selected architecture By default Branch Likely 88 m GX Linux User Guide Appendix 2 GNU X Tools MIPS Linux Toolsuite Option Description S O mno branch likely instructions may be generated if they are supported by the selected architecture An exception is for the MIPS32 and MIPS64 architectures and processors which implement those architectures for those Branch Likely instructions will not be generated by default because the MIPS32 and MIPS64 architectures specifically deprecate their use These options are defined by the macro TARGET SWITCHES in the machine description The default for the options is also defined by that macro which enables you to change the defaults Compiler Defined Symbols From the command line in GNU X Tools Shell or xterm type gt amp COOLS mips lin x cr Mips Linuxs geo v E er You will get all of the compiler defined symbols printed out on the screen Pr
57. commonly used compilation options 00 No optimization This is the default With optimization turned off GCC tries to generate code that is easy to debug you can set a breakpoint between any two statements and modify variables and the program will behave exactly as it should The Gcc also tries to generate code quickly Ol The compiler tries to moderately to reduce both the size of the compiled code and the execution time Compilation is slower than with O0 and requires more memory 02 Enables more optimizations than 01 Compilation time is even slower the resulting code should be even smaller and faster o Enables more optimizations than 02 Try hardest of all to produce fast assembly code Note that the emphasis is on fast the resulting code may take much more room in memory because certain functions may be placed in line and loops may be unrolled as if each iteration in the for loop were written out independently S Try to produce code that is small The emphasis is on size not speed This option uses many of the same optimization algorithms as 02 but with a different emphasis ffast math Make floating point arithmetic optimizations that violate the ANSI or IEEE standards Code compiled with this option may yield incorrect results but it will be slightly faster Be sure to test your program thoroughly finline functions Expand all simple functions into their callers The compil
58. d Work with GX Linux Start an xterm or Bash shell and log in as root or su We assume that sdal is the USB device in this example Insert the pendrive into your host computer that has GX Linux installed Mount the pendrive Example mount dev sdal mnt pendrive cr create the pendrive directory in mnt if it doesn t exist df cr reports back the number of blocks for all physical devices Note the number of blocks reported for sdal or your USB device name umount mnt pendrive cr Jsbin mkte dev sdal lt blocks gt Cr Ask your system administrator how to format filesystems if you are not sure how to use this command mount dev sdal mnt pendrive cr cd mnt pendrive cr cp R lt path to rootfs gt gxlinux rootfs cr ls dev cr ifthis directory is empty then you do not have any device nodes read below Make sure rootfs dev directory is populated with device nodes because they get deleted when a distclean isrun If dev directory is empty then issue a make all in GX Linux before issuing the above command umount mnt pendrive cr GX Linux User Guide E 41 Section 5 Making Modifications to GX Linux Now pull the pendrive out the host machine and with power off the target board insert the USB pendrive into the USB host socket and power on the target board assuming serial and Ethernet are connected At the MicroMonitor umon prompt issue the star
59. d the width of pointers Force long int and pointer types to be 32 bits wide If none of mlong32 mlong64 or mint64 is set the size of ints longs and pointers depends on the ABI and ISA chosen For mabi 32 and mabi n32 ints and longs are 32 bits wide For mabi 64 ints are 32 bits and longs are 64 bits wide For mabi eabi and either mips1 or mips2 ints and longs are 32 bits wide For mabi eabi and higher ISAs ints are 32 bits and longs are 64 bits wide The width of pointer types is the smaller of the width of longs or the width of general purpose registers which in turn depends on the ISA Put global and static items less than or equal to num bytes into the small data or bss sections instead of the normal data or bss section This allows the assembler to emit one word memory reference instructions based on the global pointer gp or 28 instead of the normal two words used By default num is 8 when the MIPS assembler is used and 0 when the GNU assembler is used The G num switch is also passed to the assembler and linker All modules should be compiled with the same G num value Allocate variables to the read only data section first if possible then next in the small data section if possible otherwise in data This gives slightly slower code than the default but reduces the amount of RAM required when executing and thus may be GX Linu
60. danislinaberebawsiedan Pie ai 44 6 2 2 Example With ODB senan A EE A E AE ead aria wednedxshaeys 44 6 3 Debugging Using the gdbinit ec cccceececeeeeeeeeeeeeeeeeeeeeeceeeeeseeeeesaeeeeseeeeseaeessaeeeeseeeseeeeeseseesseeeesaeeeeseeeeas 46 LO NE CW ON UN O ea EEE 47 7 1 Default Kernel Configuration with Networking Enabled cccccccccccseeeceeseeeeeaeeeeeseeeeeesseeeeeeseeseeesseneeesaaeeees 47 TZ Network COMMGUIATION scctevs ccs tavncusplandcctectxecmesinnsedsininnadlamiasucel aE aa EEA iia T aED EEEE EE 47 9 0 Senal OP ace cc cece escent tnst nnne E E EEEE niani 49 8 1 Serial Devices is gcd dcctseeacticenaanpdsteatansdidiemesdauldhoastdaseawedaiicabanadciataishctdeaenSatienenasinuiSrwnd dceidsomsl aasbesk donemesiadcseensadhvaudddubaenanden 49 9 1 1 MTVU OGM GU OUD tee cect tes vice erect oa sata etect ae cide ems en ee ES SEEE S OEE e Ra OREA aai 49 8 1 2 Default Serial Driver Configuration cccecccccsseeceeeeeeeeeceeeeeeeaeeeeeaeeeeeeeeeeeesaeaeeeeseaeeeeseeueeesaaaeeesaeeeeessaess 49 Ou Prodam ACCESS Odev U aseen ena EE E aye EEPE AEE 49 So ye SON e EE T E E E EE 49 Dr DEUC OSOE eee a E E E E E 49 5 32 Lodi via the senal POr sssri den a E O E OEE 49 oE Eo e e N O E E I TE E A A N AE NE A E EE AS A A T 49 Ae TS AC OS rss E E A E E E E E E E E E E E E E E E E E 50 O O O esa e ra ats atl ce tee aN era E E E dare ae ce a a E E a det E i 50 8 9 OMe ONSOlS Over SENA esurire E E EAEE ERA EEE E EE E EEEE EEE 50 Section 9 How
61. ddress should be annotated in your notes because you will need this IP address for loading GX Linux files via TFTP If your DHCP BootP server assigns a different IP address every time you reboot MicroMonitor you may want to consider manually setting the network IP address while in the development phase of your project because the IP address is a key parameter to your TFTP communications between the host development platform and the target board Step 3 Modify Environment Variables Open Visual X Tools or another editor and edit the master Makefile in the build directory The build directory is the gxlinux directory created at installation time Edit configuration variables as follows ARCH lt arch of target gt i e arm mips ppc etc BOARD lt csbxxx gt if not set enter the Cogent uUSBC name e g csb337 csb637 etc TGTIP lt IP address gt enter the IP address assigned to the target board in the last step Optionally you can modify the other configuration variables that apply but the three most important are the ones above Step 4 Make All From the build directory gxlinux make the example programs and create a ROM image for the romfs img filesystem by issuing the following command S make all Gr builds example applications installs them and re generates a ROM filesystem 20 E GX Linux User Guide Section 3 Getting Started Step 5 Load Binaries and Startup Script This step
62. def name atthe beginning of each source file If you have an include file in a non standard directory specify this directory in a I option For example suppose you have two directories for code usr src for source files and usr headers for header files While you re compiling in the usr src directory you can tell ccc where to find the header files through the command lt target alias gt S gcc I headers example c cr Figure 9 2 below summarizes the three primary modes of ccc with switch actions 60 E GX Linux User Guide Section 9 How to Use GNU X Tools Figure 9 2 Three Primary Modes of GCC GCC Switch Options Default Executable a out or a exe Cygwin Linked Executable named Compilands Oo 9 6 Controlling Linker from GCC Another common compilation option is 1 which specifies a library and L which specifies the path to a non standard library Important 1 must be specified at the end of the command after the source object filenames while all other options are specified before the source object filenames The examples shown are with ccc but the user can substitute g in place of gcc along with the appropriate C files and libraries needing linked Here s a typical command the inputs are object files so the command just runs the linker lt target alias gt gcc o example L src local lib main o first o lm cr This comma
63. dex so that the linker can find each module regardless of its order within the library Some systems always generate an index 70 E GX Linux User Guide Section 9 How to Use GNU X Tools when you create or modify the library with the ar command the GNU ar does this On other systems you have to put in the index yourself by using the ranlib command lf you want to create an executable file the beginning of the first file in the list of files must be the program s entry point This is not the same as the apparent entry point to your C source program Before your program begins executing the computer must execute a standard run time initialization routine To ensure that this is in place lib crt0 o must be the first file in the list of files and libraries This ensures that this initialization routine is linked to your program Alternatively you can link by using the GCC command without any C source files When GCC invokes the linker it automatically adds crt0 o and many other libraries in the proper place For example the command gcc exp o generates the following 1d command lt target alias gt S ld dc dp e start X o o a out usr lt target alias gt lib crt0 o lc In this command the run time initialization module usr lt target alias gt lib crt0 o appears explicitly in addition to requests to resolve references to the C library the general runtime library You can see what 1d command is generatin
64. e Sgp register on the basis of object size but the assembler uses Sgp for objects in sdata or sbss in any case The size of an object in the bss section is set by the comm or 1comm directive that defines it The size of an external object may be set with the extern directive For example extern sym 4 declares that the object at sym is 4 bytes in length while leaving sym otherwise undefined Using small objects requires linker support and assumes that the Sgp register is correctly initialized normally done automatically by the startup code MIPS assembly code must not modify the Sgp register 90 m GX Linux User Guide Appendix 2 GNU X Tools MIPS Linux Toolsuite Opcodes For detailed information on the machine instruction set see these manuals MIPS32 Architecture for Programmers Vol1 Introduction to the MIPS32 Architecture MIPS Technologies Document No MD00082 MIPS32 Architecture for Programmers Vol2 MIPS32 Instruction Set MIPS Technologies Document No MD00086 MIPS32 Architecture for Programmers Vol3 MIPS32 Privileged Resource Architecture MIPS Technologies Document No MD00090 NOTES amp ERRATA GX Linux User Guide E 91 Appendix 3 GNU X Tools PowerPC Linux Toolsuite Appendix 3 GNU X Tools PowerPC Linux Toolsuite MODEL target alias PowerPC alias ppc linux Freescale and AMCC formerly IBM s product line CPU TYPE 32 Bit RISC Load Store GP REGS SIZE
65. e The following table 9 1 shows how the control program recognizes different file types GX Linux User Guide E 55 Section 9 How to Use GNU X Tools Table 9 1 Controlling Compilation Linking i a Sr Lower case file extension Upper case file extension All other files together with options that GCC does not recognize are passed to 1d the linker either the native linker supplied by your vendor or the GNU linker As a result almost all linker options are available directly through GCC In the commands shown earlier in this Section the 1 and L options were actually passed to the linker In general GCC passes on unrecognized options to the linker so you can specify linker options without having to invoke the linker separately If you re writing C code you can use the g command instead of ccc You re actually getting the same compiler however when it is invoked as g the compiler expects C instead of vanilla C source code In addition g uses different default libraries lf you want either to preserve the output of GCC at some intermediate stage for debugging purposes or to manipulate the code directly you can do so Here is how each stage works preprocessing A E option in GCC sends the preprocessed code to the standard output instead of compiling the program compilation To save the assembly language output run GCC with the S option This produces files whose na
66. e most compatible architecture for the selected ABI that is mips1 for 32 bit ABIs and mips3 for 64 bit ABls In processor names a final 000 can be abbreviated as k for example march r2k Prefixes are optional and vr may be written r GCC defines two macros based on the value of this option The first is _MIPS_ARCH which gives the name of target architecture as a string The second has the form _MIPS_ARCH_foo where foo is the capitalized value of _MIPS_ARCH For example march r2000 will set _MIPS_ARCH to r2000 and define the macro MIPS ARCH_R2000 Note that the MIPS ARCH macro uses the processor names given above In other words it will have the full prefix and will not abbreviate 000 as k In the case of from abi the macro names the resolved architecture either mips1 or mips3 It names the default architecture when no march option is given Optimize for arch Among other things this option controls the way instructions are scheduled and the perceived cost of arithmetic operations The list of arch values is the same as for march When this option is not used GCC will optimize for the processor specified by march By using march and mtune together it is possible to generate code that will run on a family of processors but optimize the code for one particular member of that family mtune defines the macros MIPS TUNE and _MIPS_TUNE foo which work in the same way as the march ones described above Issue in
67. e a make command that will load the GX Linux binaries and startup script we assume you assigned the target board an IP address and edited the makefile connections are made and board is powered on S make load cr Three images should start loading onto the board see the serial terminal interface for upload responses in MicroMonitor The images loaded are as follows 1 zImage kernel 2 romfs img ROM root filesystem and 3 startlinux startup script Step 6 Reset and Boot Linux Press the board reset switch once the files have completely transferred From the serial terminal window issue the following command uMON gt startlinux cr this script calls the Linux kernel and filesystem to execute The Linux kernel should uncompress and mount a ROM filesystem If there are any errors reset the board and repeat this step Occasionally the kernel aborts on a bootup due to a corrupted flash file system Follow steps in the MicroMonitor tips section to issue a command uMON gt tfs clean to defrag the flash file system The Linux startup script is set with a Tiny Filesystem attribute that makes startlinux an executable like a batch file in DOS To change this attribute so that you can automatically boot with query into Linux with a query to stop after MicroMonitor boots up issue the following command after boot up of MicroMonitor uUMON gt tis feB co startlinux startlinux cr WARNING feB is cas
68. e any name you specify b format Read object modules in the given format To get a list of formats that 1d understands give the command objdump I and near the bottom of the options list are the supported targets and architectures This can be helpful in some cross development situations The b option applies to all object files and libraries following it on the command line until another b option appears In theory you can use this feature to link objects from several different formats into a single executable oformat format Create object modules in the given format Again objdump I gives you a list of formats that 1d understands The 1d is configured to produce the most reasonable output format for its target machine Its assumptions about what is reasonable are probably true about 99 99 percent of the time But there may be special purpose situations in which you would want another output format Here is an example of a customized 1d command lt target alias gt s ld r 0 bigoftile o progl o prog2 o lmylib cr This command links the files progl o and prog2 o and the library file usr lib libmylib a The resulting file is named bigofile o it can be linked further and may still contain unresolved references 9 9 3 Linker Scripts One advanced feature of the GNU linker is its ability to work from scripts written in its own command language If you are a true masochist you mi
69. e instructions that update the base register to the address of the calculated memory location These instructions are generated by default If you use mno update there is a small window between the time that the stack pointer is updated and the address of the previous frame is stored which means code that walks the stack frame across interrupts or signals may get corrupted data mfused madd Generate code that uses does not use the floating point multiply mno fused madd and accumulate instructions These instructions are generated by default if hardware floating is used mno bit align On System V 4 and embedded PowerPC systems do not do mbit align force structures and unions that contain bit fields to be aligned to the base type of the bit field For example by default a structure containing nothing but 8 unsigned bit fields of length 1 would be aligned to a 4 byte boundary and have a size of 4 bytes By using mno bit align the structure would be aligned to a 1 byte boundary and be one byte in size mno strict align On System V 4 and embedded PowerPC systems do not do MSUriLCUc align assume that unaligned memory references will be handled by the system mrelocatable On embedded PowerPC systems generate code that allows mMno relocateble does not allow the program to be relocated to a different address at runtime If you use mrelocatable on any module all objects linked together must be comp
70. e kernel and libraries on a Linux host and install them on the Windows Cygwin host for those who want a familiar Windows environment to perform their application development Board Connection and Initial GX Linux Bootup Make physical connections per the diagram layout in Figure 3 6 If connecting to a hub on a network disregard connecting an Ethernet cross over cable To get the target board booted up and communicating with your host Windows computer you will need to configure your serial port and HyperTerminal or other serial communications program before loading GX Linux binaries Step 1 Setup Serial Terminal e Connect the provided null modem serial cable to the target board and host computer s DB 9 Serial Port e Configure your serial terminal program to connect to the target board using the following settings 38400 baud 8 data bits No parity 1 stop bit no flow control e Connect power supply to the board and the serial terminal should show the MicroMonitor startup banner and the UMON gt command prompt Figure 3 6 Diagram of Board Connections to Host Computer Ethernet cross over cable Keyboard Mouse Monitor AC Power Null modem serial cable ETHO COM1 ttySO Serial 0 Ethernet Host Development CoJEnI O OROXX XX 12VDC Power Target Board Computer P S AC Power GX Linux User Guide E 27 Section 3 Getting Started Step 2
71. e sensitive and if you use a lower case b in the switch option you will not be able to boot into UMON again without re flashing through the JTAG which is complicated and time consuming To change the attribute back to manual boot substitute fe in place of feB in the above command above Step 7 Run Example Applications When the GX Linux boots to a Linux command shell prompt you can enter the following commands in the serial terminal to get acquainted with all of the example programs loaded in the usr bin each example file has a x file extension In the serial terminal command line interface window issue the following commands cd usr bin cr ls cr shows all examples to execute examples perform the next step hello x cr executes hello world program There are approximately 20 other programs that can be executed in the same manner and each filename ends in x extension Tryout as many of the examples as you wish Read the next section to become more familiarized with MicroMonitor GX Linux User Guide E 25 Section 3 Getting Started Step 8 How to Add Your Own Applications The fastest way to get your own application on the target board is to copy your application named with a x file extension into the examples directory which is under the build directory and issue the following command in the xterm Bash shell S make install apps romfs cr make load cr reload yo
72. e_type takes one of the following 96 m GX Linux User Guide minsert sched nops scheme Appendix 3 GNU X Tools PowerPC Linux Toolsuite values no no dependence is costly a11 all dependences are costly true store to load a true dependence from store to load is costly store to load any dependence from store to load is costly number any dependence which latency gt number is costly This option controls which nop insertion scheme will be used during the second scheduling pass The argument scheme takes one of the following values no Don t insert nops pad Pad with nops any dispatch group which has vacant issue slots according to the scheduler s grouping regroup exact Insert nops to force costly dependent insns into separate groups Insert exactly as many nops as needed to force an insn to a new group according to the estimated processor grouping number Insert nops to force costly dependent insns into separate groups Insert number nops to force an insn to a new group On System V 4 and embedded PowerPC systems compile code using calling conventions that adheres to the March 1995 draft of the System V Application Binary Interface PowerPC processor supplement This is the default unless you configured GCC using powerpc eabiaix mcall sysv eabi Specify both mcall sysv and meabi options mMcall sysv nocdabi Specify both mcall sysv and mno eabi options mcall linux On Syste
73. ed filename as its output file Not specifying c or o will tell GCC to create a default executable named a out for all cross compilers and a exe for the native Cygwin compiler One the D option acts like define in the source code it sets the value of a symbol lt target alias gt gcc c D first info D second example c The first D option sets first to the string info because of the backslashes the quotation marks actually become part of the symbol s definition This can be useful for controlling which file a program opens The second D option defines the second symbol It happens to set it to the value 1 the default but you probably don t care your program just uses an ifdef directive to check whether it s set Stop after the preprocessing stage do not run the compiler proper The output is in the form of preprocessed source code which is sent to the standard output Input files which don t require preprocessing are ignored GX Linux User Guide E 59 Section 9 How to Use GNU X Tools o Stop after the stage of compilation proper do not assemble The output is in the form of an assembler code file for each non assembler input file specified By default the assembler file name for a source file is made by replacing the suffix c i etc with s Input files that don t require compilation are ignored y Print on sta
74. eeeeeeeeceeaeeeeceeeeeseeeseeeesseeesseeeessaeeesaeeessnes 8 Section 2 0 Installation and Setup ccccceccceeeeeceeeeeeeeeceeeeneeeesensenesessoneeesonsoneseesenseeeseesoneoes 9 2 1 Standard Platform Installation and Setup on a Linux Host Workstation ccccccccseceeseeeeseeesseeeseeeeeseeeeees 10 2 2 Professional Platform Installation and Setup on a Linux Host Workstation ccccccseseeeeeeeeeeeeeseeeeesaeeeees 13 2 3 Application Development Platform Installation and Setup on Windows Host Workstation cccccseeeeeee 16 2A RIS ae EN ee este seneseueeneeesmtes E coeseaeesane eatin voce E ET E E E EE 17 2 9 Uninstal INU X OOS TOOLS US acted ceccpassdercrpee aise nienia aoaaa ea a aa aa aa aaa a a 17 SeCH N 3 0 G ting Starte sse rE EK eee a eee ee 18 3 1 Getting Started with the Standard Platform Linux HOSt naannnnnnnnnennnnennnnsnnnnnnnnnnsnnnrnrnnnsnnrrnnnrrnsnsrrrsnnrennnne 19 3 2 Getting Started with the Professional Platform on LINUX Host 00nnn0nnnnannnannnannnnnnnnnnnnnnnnnnnnnnnnnnrnnnrrnnnnnsnnne 23 3 3 Getting Started with Application Development Platform on Windows HOSt ccccseeeeeeseeeeeeseeeeesneeeeeeeeees 27 3 4 MicroMonitor Boot ROM Familiarity and TipS cceccccccseeceeceeeeeeeeeeeeeeeeseeeseeeeeeeseeeeeeseeeeeesaaeeeesseseesaeeseeesaaes 31 3 4 1 Manual TFTP Up Load Procedure ccccccccsscccscecececeeccsceceueeceueecueesaueeseeseueecs
75. ely 20 other programs that can be executed in the same manner and each filename ends in x extension Tryout as many of the examples as you wish Read the next section to become more familiarized with MicroMonitor Step 8 How to Add Your Own Applications The fastest way to get your own application on the target board is to copy your application named with a x file extension into the examples directory which is under the build directory and issue the following command in the xterm Bash shell S make install apps romfs cr make load cr reload your images to the target board After uploading three files to the target board startlinux zZimage and romfs img you can manually start GX Linux by issuing the following commands er get a command prompt after upload reset cr get the board in a refresh state S startlinux cr Linux boots to a user prompt On the target board in the usr bin directory are a dozen example programs that can be run from the Minicom interface Issue the following commands d usr bin cr ls cr You can see all examples they have a x file extension on them To run each example issue the by name command double x cr t floats cr hellosex Gr etc Step 9 Useful Linux Commands cat proc cpuinfo Show information such as bogomips architecture and manufacture information reboot Reboots system into UMON 30 E GX Li
76. en in an assembly language and produces an object module By convention assembly language programs have the extension s If no errors occur during assembly and if the object module contains no references to external imported symbols the assembler makes the file executable and names it a out If the object module includes references to external symbols a out is not an executable The linker is able to link this object module with other modules to produce an executable program To invoke the assembler enter the command lt target alias gt s as options lt list of source files gt cr Where list of options is a series of assembly options and list of source files is one or more assembly language files s S capital S requires GCC to direct the source file to the preprocessor and then on to the assembler Unlike most Unix assemblers the GNU assembler can work on several files at a time The assembler has many options most of them are architecture specific and are used to describe the target processor more precisely These options will be important to you if you are cross compiling check the FSF s manual for more details Each appendix in this user guide briefly discusses the target dependent compiler and assembler options The following are a set of options and controls that are generally useful for invoking all GNU assemblers Common assembler switch options to all Targets a cdhIns file
77. er Machine Dependent Options The following options are available when as is configured for the ARM processor family Options C Description gt marm7 tdmi Arm 7 processors marm8 10 Arm 8 processors marm9 920 9tdmi Arm 9 processors mstrongarm110 0 StrongARM processors marmv4 marmv4t Arm architectures marmv5 marmvSte No float load store multiples FPA10 and 11 co processor Select which procedure calling convention is in use mapcs 32 32 bit APCS Ce Select little endian EL output the default GNU ARM Assembler Quick Reference A summary of useful commands and expressions for the ARM architecture using the GNU assembler is presented briefly in the concluding portion of this Appendix Each assembly line has the following format lt label gt lt instruction or directive gt comment Unlike the ARM assembler using the GNU assembler does not require you to indent instructions and directives Labels are recognized by the following colon instead of their position at the start of a line An example follows showing a simple assembly program defining a function add that returns the sum of two input arguments NN A Sent ion Cext x global add give the symbol add external linkage add ADD rm TU rl add input arguments MOV pc Lr return from subroutine end of program GNU Assembler Directives for ARM The follow is an alphabetical listing of the more command GNU assembler d
78. er gets to decide whether any function is simple or not Inline expansion is a two edged sword it can make a program faster by eliminating calling overhead or slower by making instruction cache performance worse fno inline Inhibit all inlining even inlining that is requested by the inline keyword in the source code The Gcc_ performs inlining according to statements in the source code with both 01 and 02 the keyword is ignored if optimization is not in effect e Ou O Ds On some CPUs loop unrolling can be a very important optimization It minimizes loop overhead and creates many opportunities for further optimizations With the funroll loops option GCC unrolls all loops that have a fixed iteration count known at the time of compilation Loop unrolling is another risky optimization it can improve 66 E GX Linux User Guide Section 9 How to Use GNU X Tools performance but it can also penalize performance significantly the object file becomes larger which can significantly hurt cache performance and compile time also increases 9 7 7 Passing Options to the Assembler or Linker The Gcc allows you to pass options directly to the assembler or linker when they are involved Wa options Pass the options to the assembler Wil ODELONS Pass the options to the linker In both cases the option list is just a list of options recognized by the assembler or the linker There must not be
79. er of the ARM embedded RISC microprocessor family ARP Address resolution protocol development on a particular board boot options See UMON documentation BSP BusyBox Open source code that combines tiny versions of common utilities and a shell into a single small executable CLUT Cross build The process of running a toolchain on your host computer to produce executables for a different target file system also Known as cross compile For example you may cross build on the host to produce files for the real target hardware A process that typically runs in the background behind the scenes that is usually invoked as part of the system startup scripts These processes usually run continuously as helper utilities for various system operations such as networking DHCP Digital Signal Processor A microprocessor specialized to process data in real time Certain operations can be executed in parallel which results in higher processing capacity for a given clock speed DSP ELF ELF Executable and Linking Format is a binary format originally developed by USL UNIX System Laboratories Because of its increased flexibility over the older a out format that Linux previously used the GCC and C library developers decided to move to using ELF as the Linux standard binary format also The directory structure beginning with comprising configuration files applications libraries and an operating system GDB Gnu DeBugger A
80. er the Build menu The Build window at the bottom of Visual X Tools shows the verbose output of the build After completion of the build go to the next step Step 5 If you selected the Debug Active Configuration in Step 3 then click on Build Copy Debug Image to Examples Dir If you selected the Release option for Active Configuration in Step 3 then click on Build Copy and Strip Release to a Binary Image thenclick on Build Copy Release Image to Examples Dir Step 6 Issue the following commands in xterm Bash shell for rebuilding the romfs img filesystem and replacing the existing version on root filesystem S make install apps romfs cr S make load cr To get more specific information on how to use Visual X Tools consult the Visual X Tools User Guide END OF EXAMPLE PROGRAM 34 E GX Linux User Guide Section 5 Making Modifications to GX Linux section 5 0 Making Modifications to GX Linux Every developer will have to make at least one or more modifications to GX Linux and depending on which Platform you are working with the steps may vary The following list names the appropriate section for modifying GX Linux on your platform version Section 5 1 Modifying GX Linux Standard Platform Section 5 2 Modifying GX Linux Professional Platform 5 1 Modifying GX Linux Standard Platform No changes to the Kernel and library binaries can be made using the GX Linux scripts and
81. ess Ctr1 c to exit this mode Assembler Machine Dependent Options Options i Description _ _ _ _ _ O O S 59 92 Do not remove unneeded NOPs or swap branches _ 9 g2 Do not remove unneeded NOPs or swap branches GNUM Allow referencing objects up to NUM bytes implicitly with the gp register default 8 Ignored accepted for compatibility w other MIPS assemblers Don t generate code specific to CPU For mCPU and no mCPU mCPU CPU must be one of 3900 4010 4100 Remove unneeded NOPs do not swap branches trap no break Trap exception on div by 0 and mult overflow Not supported for ISA 1 mips2 and higher Assembler Special Characters Syntax Inline comment char H Line comment char H Statement separator none Other notes S used as register designator Register Names General registers 0 31 FP registers Som acon aes alk Value registers SVO OL Argument registers Sa0 Sa3 Temporary registers St0 St7 GX Linux User Guide E 89 Appendix 2 GNU X Tools MIPS Linux Toolsuite Saved registers s0 Ss7 Temp expr registers St8 S t9 Kernel resvd registers kt0 kt1 Global ptr register Sgp Stack ptr register Ssp Frame ptr register Sfp Link retn register Sra FP result registers STv0 Stvi FP temp registers SECl ore3 FP working registers ft0 ft7 FP argument registers Sfa0 Sfa7 FP expr registers STes SttlLi FP saved registers Srs0 Sts7 Program counter SOG Status
82. et alias as Invokes the GNU assembler that produces binary code from the assembly language code and puts it into an object file e target alias ld Invokes the linker that binds the code to addresses links the startup file and libraries to the object file and produces the executable binary image 9 4 Using the GNU X Tools Toolsuite The first step to developing code with the GNU X Tools toolsuite is creating and editing the source code Microcross provides the Visual X Tools IDE as companion product for code editing and project management however a programmer can use any text line editor to create source files and makefiles and use the GNU X Tools as the production build environment Free editors under Cygwin include VIM an improved VI editor clone and Xemacs a powerful editor and project manager Under Linux the user also has a wide variety of choices including the Microcross Visual X Tools IDE and GNU Xemacs edit see docs in the Linux distribution 9 4 1 Simple Example Start a shell xterm on Linux and GNU X Tools Shell on Windows Cygwin and issue the command xtools lt target alias gt where the target alias is selected from the toolsuite you are using i e arm linux mips linux mipsel linux ppc linux etc depending on the toolsuite you have installed The following simple example shows you quickly how easy it is to get a program compiled linked and executed in an Instruction Set Simulator ISS and debug it using Visua
83. etc Here is a quick example of how to use objcopy refer to the binutils documentation in the docs directory on the distribution CD or in the Cygwin docs directory for details on how to use From the Shell issue the following commands substitute your target alias and bfdname as necessary e g notional only S xtools arm linux cr arm linuxS cd home test cr armelinuxs geo g O diy velit div c er arm lainuxs Ob Copy S O binary div elt div bin cr Note The S strips all symbols including the debugging symbols put in the file by using the g option out to make the object as small as possible The O binary specifies the output target format The input file is div elf andthe output file is div bin 9 11 Creating Updating Libraries The command ar creates libraries or archives of object modules They are similar to the Unix Linux utilities with the same names except that you do not need a separate ranlib This section gives a brief description of how to use these utilities in the GNU X Tools command shell In naming a library for use with GNU X Tools always use the prefix lib and suffix extension a with your static library name this is the GNU convention and is necessary for GCC to automatically scan the library at link time so the syntax for linking a particular library say 1ibm a the math library is 1m To create a new library use the ar command as follows lt t
84. ficient since it will take three instructions to fetch the value of a global symbol Note that some linkers can create multiple GOTs If you have such a linker you should only need to use mxgot when a single object file accesses more than 64k s worth of GOT entries Very few do These options have no effect unless GCC is generating position independent code Generate PIC code suitable for some embedded systems All calls are made using PC relative address and all data is addressed using the gp register No more than 65536 bytes of global data may be used This requires GNU as and GNU ld which do most of the work This is the default the default mhard float Generate output containing floating point instructions This is the default if you use the unmodified sources Generate output containing library calls for floating point msingle float mdouble float mlongo4 mlong32 a membedded data mno embedded data The msingle float switch tells GCC to assume that the floating point coprocessor only supports single precision operations as on the r4650 chip The mdouble float switch permits GCC to use double precision operations This is the default Force int and long types to be 64 bits wide See mlong32 for an explanation of the default and the width of pointers Force long types to be 64 bits wide See mlong32 for an explanation of the default an
85. filesystem with BusyBox You can build your own applications load them into usr bin or any other directory and run them on the target uUSBC e Build your application s and name the binary executable with a x file extension recommended e Copy your application files into the lt build directory gt examples directory 36 E GX Linux User Guide Section 5 Making Modifications to GX Linux e To install the your own applications re build the ROM filesystem and reload the target board via TFTP assuming the target board is powered on and connected to your network issue the following commands Spd 4Duild dir clory gt cr S make install apps romfs er S make load cr If you have any load errors make sure your target IP address is correct in the Makefile build directory 5 3 Changing the Kernel Configuration 5 3 1 Configuration Files The Linux kernel supplied with your BSP is pre configured and ready for use If your project requires components that are not contained in the default GX Linux kernel you may want to change the kernel configuration The kernel configuration is expressed in two files 1 the config working copy and 2 kernel conf master backup copy The working copy is retained at gxlinux linux config the master backup copy at gxlinux config lt csbxxx gt kernel conf The configuration file is read and modified by xconfig described below After running xconfig
86. from the Build Directory make romfs ttftp lt target ip gt put romfs img romfs img 48 E GX Linux User Guide Section 8 Serial Port 8 0 Serial Port 8 1 Serial Devices 8 1 1 Introduction In this section we discuss the serial port and the two linux devices listed below e dev ttySO e devi ttyS1 e dev console 8 1 2 Default Serial Driver Configuration The GxX Linux BSP ships with a default kernel configuration that has the appropriate serial driver enabled as shown in the table below e dev ttySO Used for console e devittyS1 Available e dev console Mapped to dev ttySO 8 2 Program Access to devittySo With serial port support enabled you can use the dev ttyS0 Linux device to programmatically send and receive characters over the serial port For reference the make xconfig setting has the effect of enabling the CONFIG_AT91RM9200 SERIAL definition used during the build of the kernel If you hardware supports dev ttyS1 this will enable the second serial port as well 8 3 System Console 8 3 1 Default Console The dev console is the device underlying system s stdin stdout and stderr file descriptors In the GX Linux BSP the kernel first tries to open dev console when it boots to serve as the console Failing that it will try to open dev ttyS0O 8 3 2 Login via the Serial Port If you attach a terminal or a computer running terminal emulation software to the target h
87. fs clean to defrag the flash file system The Linux startup script is set with a Tiny Filesystem attribute that makes startlinux an executable like a batch file in DOS To change this attribute so that you can automatically boot with query into Linux with a query to stop after MicroMonitor boots up issue the following command after boot up of MicroMonitor UMON gt tfs feB cp starctlinux startlinux Cx WARNING feB is case sensitive and if you use a lower case b in the switch option you will not be able to boot into UMON again without re flashing through the JTAG which is complicated and time consuming To change the attribute back to manual boot substitute fe in place of feB in the above command above To stop the automatic boot press any key while UMON is booting and before Linux boots The bootup will stop at the UMON command line GX Linux User Guide E 29 Section 3 Getting Started Step 7 Run Example Applications When the GX Linux boots to a Linux command shell prompt you can enter the following commands in the serial terminal to get acquainted with all of the example programs loaded in the usr bin each example file has a x file extension In the serial terminal command line interface window issue the following commands cd J ust bin cr ls cr shows all examples to execute examples perform the next step hello x cr executes hello world program There are approximat
88. fter MicroMonitor boots up issue the following command after boot up of MicroMonitor uMON gt t s feB cp startlinux startlinux cr WARNING feB is case sensitive and if you use a lower case b in the switch option you will not be able to boot into UMON again without re flashing through the JTAG which is complicated and time consuming To change the attribute back to manual boot substitute fe in place of feB in the above command above To stop the automatic boot press any key while UMON is booting and before Linux boots The bootup will stop at the UMON command line prompt Step 7 Run Example Applications When the GX Linux boots to a Linux command shell prompt you can enter the following commands in the serial terminal to get acquainted with all of the example programs loaded in the usr bin each example file has a x file extension In the serial terminal command line interface window issue the following commands cd usr bin cr ls cr shows all examples to execute examples perform the next step hello x cr executes hello world program There are approximately 20 other programs that can be executed in the same manner and each filename ends in x extension Tryout as many of the examples as you wish Read the next section to become more familiarized with MicroMonitor GX Linux User Guide E 21 Section 3 Getting Started Step 8 How to Add Your Own Applications The fastest
89. g the Kernel Configuration ccccccccccseeeeeeseeeeeeeeeeeeeseeeeeeeeeeeeseeeeeeseeeeesseeeeeeseeeeeessaeeessaeeeesaaeseeeaaess 37 53 1 Configu ur tion FIGS ssassn nnna a a a Se 37 5 3 2 Changing the Working Configuration cccccccccseecceceeeeeeeseeeeeeseeseeesaeeeeeseeseeeseeeeeesseeeeessegseeeseeeeeesaeeeeeeas 37 5 3 3 Resetting the Kernel to the Default CONFIQUrATION cc ccceccccecceeeeeeceeeeeeseeeeeeeeeeeeesaaeeeesseeeeesaeeeeesaneeeeas 38 5 3 4 Customizing the Kernel Configuration ccccccccseecccceeeeeeeeeeeeeeeeeeeesaeeeeeeseeeeessaeeeesseeeesseeseesaaeeeeesaeeeeeeas 38 g4 Changing the Target File Sy SUG it cai ventatncstaiecouseideenancsa soseneieaaceruonsdeanssea tan cenmenassiamesieguend donadene EA 38 5 4 1 Adding Content to the Target File System cccccccssseecceesececeeeeeceeueeecsegeeeceeuseeessaueeessageeesseaeeessenseneees 38 iv E GX Linux User Guide 5 5 Putting the New System on the Target Hardware ccccccseccceceeeeeeeeeeeeeeeeeeeeeeeeeeesseeeesseeeeeeseseeesaeeeeesaaeeees 39 5 5 1 Putting the New System on the Target Hardware ccccccseecceeeeeeeeeeeeeeesaeeeeeseeeeeeseeeeeesaeeeesseneeeeeaaaes 39 5 6 Read Only and Read Write File SYStOMS cccccsscccecseeeeeeeeeeeseeeeeeeaeeeeeeseeeeeeeeeeeeessaeeeessegeeeseaeeeeesseeeeesseeees 39 5 6 1 ROMFS File System eesosa dennan enin a aa a a N a a EE a a EEn E aia a 39 5 6 2 NFS Mounted Root Fi
90. g when you compile a program on your system by invoking GCC with the v verbose option 9 9 2 Linker Options The GCC passes any options it does not recognize to the linker The most important options can therefore be placed directly on the GCC command line These options are 0 name x Instead of naming the executable output file a out or a exe native builds under Cygwin it names it name x Other popular naming extensions for embedded applications include name elf name coff name srec and name bin Microcross has standardized all of its cross executable names to the x extension lname Link the program to the library named 1ibname a The linker looks in the directories 1ib and usr lib to find this library Note that the GNU linker truncates the name s prefix and extension i e lib and a are not necessary for libname a as a linked library file If you create your own libraries to link into your program you will need to name them libname a and link in as lname Ldir To find any libraries look in the directory dir before looking in the standard library directories lib and Yasrib S Remove the symbol table from the executable output file This makes the output file significantly smaller but makes debugging nearly impossible Therefore this option should not be used until the program works successfully Note that using the
91. ght be able to avoid running GCC altogether you might be able to implement your own compiler as a linker script There are a few situations in which you would actually need a linker script but you should be aware that they exist for purposes like e Gaining tight control over the format of the output file perhaps so an embedded application will fit into the smallest possible ROM perhaps to optimize link order 72 E GX Linux User Guide Section 9 How to Use GNU X Tools e Supporting an object format that 1d does not provide perhaps an object format of your own design or an object format for some special purpose operating system Microcross recommends starting with the default linker script and modifying it to meet your needs To extract the standard linker script into a file type the command lt target alias gt ld verbose gt linker ld cr This command will create a file named linker 1ld and you will need to open this file in an editor to delete the header lines before and including and the footer single line Then the script file can be saved or copied into a source directory and be used with the Gcc option W1 T linker ld to replace the standard linker script Now you can modify the linker script with confidence that you have a working startup script 9 9 4 Link Order Optimization If you have done a lot of development work you have probably noticed that the order in which you link yo
92. h multiple CD ROM drives that have differing naming conventions Step 4 Install the GNU X Tools command tool for the Bash xterm shell by executing the following commands 7 Ca 7 Cr tar xvzf mnt cdrom bin rcfiles tgz cr At this point you should be able to execute the xtools command tool inside of the Bash shell by its name The command xtools cr should invoke the abbreviated tool help screen that shows the basic operating commands see Section 10 for a complete description of the command tool Step 5 To install the two GNU X Tools toolsuites from the GX Linux CD simply substitute the target alias i e lt target alias gt arm linux mips linux mipsel linux ppc linux arm elf mips elf etc and issue the command xtools install lt target alias gt cr for the first toolsuite xtools install lt target alias gt cr for the second toolsuite These commands will extract the toolsuite tarballs installing all files in their appropriate locations The install command assumes the default archive source path is mnt cdrom bin using mnt cdrom as the CD ROM mount point If your default mount point is different you can change the default value by editing 10 m GX Linux User Guide Section 2 Installation and Setup usr bin xtools file If you would like to override the default path to the distribution medium you may enter the command as xtools install arm linux lt arc path gt
93. have instructions to directly access half word objects in memory mno alignment Generate code that assumes that the MMU will not trap unaligned traps accesses This produces better code when the target instruction set does not have half word memory operations implementations prior to ARMv4 Note that you cannot use this option to access unaligned word objects since the processor will only fetch one 32 bit aligned object from memory The default setting for most targets is mno alignment traps since this produces better code when there are no half word memory instructions available mcpu lt name gt This specifies the name of the target ARM processor GCC uses this name to determine what kind of instructions it can use when generating assembly code Permissible names are arm2 arm250 arm3 arm6 arm60 arm600 arm610 arm620 arm7 arm7m the default setting arm7d arm7dm arm 7di arm7dmi arm70 arm700 arm700i arm710 arm710c arm7100 arm7500 arm7500fe arm tdmi arm8 strongarm strongarm110 strongarm1100 arms arm810 arm9 arm920 arm920t arm9tdmi arm9e and arm1020t xscale mtune lt name gt This option is very similar to the mcpu option except that instead of specifying the actual target processor type and hence restricting which instructions can be used it specifies that GCC should tune the performance of the code as if the target were of the type specified in this option but still choosing the i
94. iled with mrelocatable or mrelocatable lib On embedded PowerPC systems generate code that allows does not allow the program to be relocated to a different address at runtime Modules compiled with mrelocatable lib can be linked with either modules compiled without mrelocatable and mrelocatable lib or with modules compiled with the mrelocatable options mno toc On System V 4 and embedded PowerPC systems do not do mtoc assume that register 2 contains a pointer to a global area pointing to the addresses used in the program mlittle On System V 4 and embedded PowerPC systems compile code MLI CCLo 7cndi an for the processor in little endian mode The mlittle endian optionis the same as mlittle mba g On System V 4 and embedded PowerPC systems compile code mbig endian for the processor in big endian mode The mbig endian option is the same as mbig mprioritize This option controls the priority that is assigned to mrelocatable lib mno relocatable lib restricted dispatch slot restricted instructions during the second insns priority scheduling pass The argument priority takes the value 0 1 2 to assign no highest second highest priority to dispatch slot restricted instructions msched costly This option controls which dependences are considered dep dependence type costly by the target during instruction scheduling The argument dependenc
95. in C a leading Ox indicates a hexadecimal value and a leading 0 indicates an octal value sE Fast skip white space and comment preprocessing assume source is compiler output Warning if you use when the files actually need to be preprocessed if they contain comments for example as does not work correctly gstabs Generate stabs debugging information for each assembler line This may help debugging assembler code if the debugger can handle it Print a summary of the command line options and exit TERRE Add directory dir to the search list for include directives You may use l as many times as necessary to include a variety of paths The current working directory is always searched first after that as searches any I directories in the same order as they were specified left to right on the command line Don t warn about signed overflow Issue warnings when difference tables altered for long displacements L Keep in the symbol table local symbols starting with L L keep locals Keep in the symbol table local symbols On traditional a out systems these start with L but different systems have different local label prefixes M or mri This changes the syntax and pseudo op handling of as to make it compatible with the ASM68K or the ASM960 depending upon the configured target assembler from Microtec Research MD __ ass can generate a dependency file for
96. inux distribution CD You can also tryout your TCL TK configuration by issuing the command lt target alias gt gdbtk and observe the start of the program if there are any errors then you know that there is a mis match in configuration Also you can check your TCL TK version by issuing the following commands from an xterm Bash shell teln er info tclver cr version is echoed back exit cr oo U o0 If you need to install the right version of TCL TK the following is the command to issue to install the library from Microcross CD ROM login as su or root if not already done so xtools install share gdbtcl cr exit er 14 m GX Linux User Guide Section 2 Installation and Setup You should now be logged out of su root Note if you had any errors in the last step due to xtools command script not finding the proper mount path then simply add the path after share gdbtcl e g xtools install share gdbtcl mnt cdrom bin Step 7 Select or create an install directory on your Linux host machine preferably in your home lt user name gt directory or a directory where you have full permissions We call this the install directory because the build directory will be untarred to this directory The build directory is named gxlinux and when you untar the GX Linux BSP tarfile it creates this build directory at the point of install The Build contents for GX Linux Professional
97. ion on the machine instruction set see these manuals The PowerPC Architecture A Specification for a New Family of RISC processors Morgan Kaufmann Publishing PowerPC Microprocessor Family The Programming Environments Motorola Doc number MPCFPE AD NOTES amp ERRATA 100 m GX Linux User Guide Appendix 4 Common Minicom Problems Appendix 4 Common Minicom Problems If you are having problems with Minicom first try clearing all settings for Modem and dialing under Configure Minicom Save the settings this requires root permissions Problem Solution Error message Device dev ttySO Permissions for device are set improperly As root user enter chmod o rw access failed Permission denied dev ttyS0 e In Configure Minicom gt Serial port setup check that Serial Device is consistent with the port you are using e In Configure Minicom gt Serial port setup ensure that Hardware No terminal activity Flow Control and Software Flow Control are both set to No e f possible connect the serial cable to another serial port on a Linux workstation and verify data can be exchanged over the serial cable in both directions Settings revert to original when Make sure you use Configure Minicom gt Save setup as dfl after making Minicom is restarted changes To do this you must run Minicom as the root user GX Linux User Guide E 101 Appendix 5 Glossary Appendix 5 Glossary TERM ARM Ltd ARM Ltd is the develop
98. irectives GNU Assembler Directive Inserts the string as data into the assembly like DCB in armasm Like ascii but follows the string with a zero byte 80 m GX Linux User Guide Appendix 1 GNU X Tools ARM Linux Toolsuite GNU Assembler Directive Aligns the address to lt power_of_2 gt bytes The assembler aligns by adding bytes of value lt fill_ value gt or a suitable default The alignment paligi lt power OF 2 gt isil value gt lt max padding gt will not occur if more than lt max_padding gt fill bytes are required similar to ALIGN in armasm Inserts a list of byte values as data into the assembly like DCB in armasm Sets the instruction width in bits Use 16 for Thumb and 32 for ARM assembly similar to CODE16 and CODE32 in armasm Use with if and endif similar to ELSE in armasm Marks the end of the assembly file usually omitted endif Ends a conditional compilation code block see if ifdef ifndef similar to ENDIF in armasm Ends a macro definition see macro similar to MEND in armasm Ends a repeat loop see rept and irp similar to WEND in armasm This directive sets the value of a symbol similar to EQU in armasm Causes assembly to halt with an error Exit a macro partway through see macro similar to MEXIT in armasm This directive gives the symbol external linkage similar to EXPORT in armasm Inserts a list of 16 bit values as data into the assembl
99. iss dnee A A A AA 72 9 94 LiNK Ord r OPUmMIZaNON sac ct ores caiscdeceraie cive de oyediteneueconsunee dates weeacedereecuted mu aeeneseeectesasesceeecontseee see seiendiaecou 73 Seo IGS RONE CIO n sncsacebeabhesaesteb xeqnes E E 73 9 10 Object Translation ELF to Binary SREC etc 20 0 0 cecccccseececcseseecseseeeceeesceeseaeeessaeeeeseueesssasseeessageeesseass 73 9 11 Creating Updating Libraries ccccccccssseccccesseeceessececsaseccceuseecesaeeecsasseesceuseeeesageessaaeeeeseasesessaseeessaseessssass 74 9 12 GNU MANS cts scec tac enc cee pace rao aetna R oa ddaak in apie oeeadimaba ances ties 75 Appendix 1 GNU X Tools ARM Linux Toolsulte cccccceseeeeeeeeseneeeeeeeseneeeeseneeneseesenees 76 Appendix 2 GNU X Tools MIPS Linux Toolsulte ccc cccceeeeeeeeeeeeneeeeseneenesenseneeeesenees 84 Appendix 3 GNU X Tools PowerPC Linux Toolsuite ccccccceeeeeeeeeeeeeeeneeeeseneeneneesenees 92 Appendix 4 Common Minicom Problems cccccseceeeeeeeeeeeeeeeeseneenesensoneeeesonseneeneseneees 101 Appendix 5 Glossary arta eciase eee etme cee ester ace te teen erecta 102 Appendix 6 Additional RESOUPCES ccccccceeeeeeeeeeeeeeeeeeeeeeeeseeseeseeseesensonsonsonsonsensenseneseess 104 vi E GX Linux User Guide Section 1 Overview Section 1 0 Overview and System Requirements 1 1 Overview The GxX Linux User Guide for building Embedded Linux applications has important tutoria
100. ized such that the cross toolsuite components for the designated target are invoked by the familiar command names in lieu of the native tool chain elements For example after starting a shell using the command line xtools arm elf the command ccc would actually start the compiler arm elf gcc This facility allows the command line user to execute the cross tools using the same command names as used in the native shell environment This remapping of tool command names remains in effect until the shell is exited via Ctrl D or the exit command The GX Linux source tree is configured for cross compilation so the command is not required for any builds or makefile targets 3 xtools status path prefix This command generates a summary screen which displays the installation status of each GNU X Tools cross toolsuite in terms of the types counts and locations of files associated with each toolsuite The command displays the toolsuite status by target alias vs the population of files in the following format Column 0 Target Name target alias for this toolsuite Column 1 usr bin lt target alias files Column 2 usr lt target alias gt bin files Column 3 usr lt target alias gt lib files Column 4 usr lt target alias gt include files Column 5 usr lib gcc lib lt target alias gt files Column 6 usr man manl lt target alias gt files Column 7 Total file count for this toolsuite The optional pa
101. l GDB gt xtCools lt target alilas gt Cr In our example we use the arm linux S xtools arm linux arm linuxS cd home test cr In the last step we assumed that the Microcross test directory either was installed in Cygwin s home test or Linux s home test arm lainuxs gce g O pascal x pascal c cr GX Linux User Guide E 53 Section 9 How to Use GNU X Tools The program was compiled and linked in one step You will need to add this file to the Linux filesystem and run it on the target processor using the procedure in Section 3 To debug this simple example follow the procedure in Section 6 This concludes the simple example showing how easy it is to compile and link a program with GNU X Tools The GNU X Tools toolsuite is very powerful and can build any conceivable program a developer can code Now we need to go into more detail on how the GNU X Tools work 9 4 2 GNU X Tools Toolsuite Description The GCC program is actually a control program that executes the compiler components to produce the desired output which is usually a compiled and linked executable program image By manipulating the many GCC options and controlling the input file types the functions of GCC are greatly expanded The ccc however is but a single component It is actually a control program that calls other components that perform separate steps to create an executable binary The components are described as follows and show graphically in Fig
102. l GDB Step 1 Start gdbserver on the Cogent uSBC Using the Minicom interface to Linux running on the Cogent uSBC issue the following command gdbserver localhost 2001 usr bin div x cr Step 2 Start Visual GDB Issue the following set of commands in xterm shell the directory information is notional use your path setting S cd home steve gxlinux examples cr q arm linux gdbtk divix cr Click on File Target Settings and select GDBserver TCP from the drop down list Enter the Hostname the Microcross pre assigned host is the IP address 192 168 0 110 Next enter the Port number and the Microcross port number assigned is 2001 Click OK and click on the Run Connect target menu item Set your breakpoints and click on the Run icon You should now be able to single step through the example program 6 2 2 Example with GDB Debugging the program Once you have placed your executable ELF program in the target hardware s file system it is ready for debugging using the following steps On the Linux workstation you will need the same debug able ELF version of the program in the same directory where you will invoke arm linux gdb 1 Start the gdbserver On the target hardware invoke the gdbserver in the directory where you have the file you are debugging the flat or xflat format version of your program To start the target hardware side of the GDB session do one of the following
103. l information on how to use the BSP and tools effectively and jump start the learning process so you can focus on developing your application Specifically this User Guide provides information on how to get the GX Linux setup with GNU X Tools and GX Linux Board Support Package BSP and building applications for the target board Two versions of GX Linux are offered Standard Platform and Professional Platform There are differing requirements for each Platform System Requirements for GX Linux Software BSP Installation 1 Hardware Linux OS and Host with an x86 or Intel Pentium family processor keyboard mouse video monitor 2 Linux distribution pre installed on a host computer Red Hat Linux 7 x 8 0 9 0 EWS v3 0 or newer complete install Debian complete install Linspire Linux v4 5 Developer s Edition 3 CPU clock rate 400 MHz or higher i586 i686 PC 4 Recommended system RAM 256 MB 5 Hard disk space required 1 GB 6 A network card installed and configured on the host computer 7 A Cogent OEM board with breakout board and power supply 8 RS 232 serial port female to female 9 pin NULL modem cross over or a hub for Ethernet connection 9 Ethernet cross over cable for standalone configuration or two standard UTP patch cables for a LAN Workgroup configuration 1 2 Components of the GX Linux Standard Platform The GX Linux Standard Platform package includes a single compact disk CD ROM loaded with GNU X Tools
104. lesystem ccccccccccseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeseeesseeeeeseeeeesseeeeeeseaeeeessaeeeesaaaeeeesaess 39 5 6 3 Writing to On Board Flash via a Pendrive USB cccccccecseeeeeeeeeeeeeseeeeeesaeeeeeeseeeeeesaaeeeesaeeeeesaeeeeeesaees 41 5 6 4 How to Prepare a Pendrive with a Root Filesystem and Work with GX LINUX ccccecceesseeeeeeeeeeeeeeeees 41 5 6 5 Writing to On Board Flash via MMC SD Card cccccecccccseeceeeeeeeeeeeeeeeesaeeesseeeeeeseeeeeeseaeeeesaaeeesaneeeesaaes 42 5 6 6 Writing to On Board Flash via a Compact Flash Card cccccccccccseeeeeeeeeeeeeeeeeeeseeeeeeseeeeeeeeeeeesaeeeeesaess 42 Section 6 0 Debugging Applications cccccceceseeeeeeeeeeeeeeceeseeeeeeeeeeeeeeeeeseaesenesenesenesenesenes 43 Ot ING SDB D6 OW OG Sista cece seas E E couse A E E shannued sacesuesataes sat ETEO 43 Out ODEDE UJUE ann E canes Sune nas soueaecedacdafendemeeaaasand adap seca ante dentaietncedendendasenan E 43 adie GIDS INO sesesetec sates E E a ededent E ant sian cued aia susdaceusurusgeneaesnee E 43 to GGDSErVer COMMUNICAONS xr icndsarahocesinadnendesdusduecadacdacasimanscatandscansundaeieaessananbscusankond E 43 Oha 8 91652 FON ENO eee arene EE ne ee ree ee eee eee ee eee eae ere nee 43 Gite WED AIG FCS aeee E E EA EAEE EEEE 44 O Vic ual DE een E E E ANENE E dear semtezeewatianeess 44 62 DeDugging Examples sesei er eee e e ern ee e e e ere 44 6 2 1 Example With Visual GDB isseire se
105. ll start by listing a few options for controlling the warning messages that GCC produces There are many options for controlling warnings it s possible to request or inhibit many warning messages on a per message basis We re not sure that s really useful we ll limit ourselves to a few options that control large group of messages W Suppress all warning messages W Produce some additional warning messages about legal but questionable coding practices Wall Produce even more warning messages about questionable coding practices Wtraditional Produce warning messages about code that is legal in both the Kernighan and Ritchie and ANSI definitions of the C language but behaves differently in each case Werror Make all warnings into errors that is don t attempt to produce an object file if a warning has occurred Now we ll discuss how to control various features of the C and C languages There are basically three options to worry about traditional ansi and pedantic In most cases it s fairly easy to tell which you want Older C code code that pedants the standard should be compiled with traditional Newer code that has been written to conform to the ANSI standard should be compiled with ansi Either option can accept prototypes where you specify the arguments on the same line as the function name asin func char arg 62 E GX Linux User Guide Section 9 How to
106. llows you to see what is going on inside another program while it executes or what another program was doing at the moment it crashed GIO or GPIO General Purpose Input Output hardware lines BOOTP Network protocol allowing a network device to obtain an IP address and other information from a server Daemon File system General Purpose Processor A microprocessor that is not specialized for real time parallel processing of data GNOME See GNU Networked Object Model Environment NU Networked Object Module A user friendly set of applications and desktop tools used in Environment conjunction with a window manager for the X Window System GNOME is similar in purpose and scope to CDE and KDE but GNOME is based completely on Open Source software GPP See General purpose processor Graphical user interface Host Computer The Linux based desktop system used for software development Host Linux Refers to the Linux operating system running on the host computer See also User mode Linux 102 m GX Linux User Guide TERM Host Shell JFFS JFFS2 JTAG KDE K Desktop Environment Linux Kernel Linux Workstation Minicom MMU NFS OSD Target File System Target Hardware TFS Toolchain uMON XIP x lt C a NINJ a OOW OINIO Appendix 5 Glossary The Linux terminal shell running on the host computer The default prompt shell is for normal users and for root
107. m V 4 and embedded PowerPC systems compile code for the Linux based GNU system code for the Hurd based GNU system code for the NetBSD operating system maix struct return mabi altivec Return all structures in memory as specified by the AIX ABI Extend the current ABI with AltiVec ABI extensions This does not change the default ABI instead it adds the AltiVec ABI extensions to the current ABI Disable AltiVec ABI extensions for the current ABI mprototype mno prototype o mmvme mads myellowknife On System V 4 and embedded PowerPC systems assume that all calls to variable argument functions are properly prototyped Otherwise the compiler must insert an instruction before every non prototyped call to set or clear bit 6 of the condition code register CR to indicate whether floating point values were passed in the floating point registers in case the function takes a variable arguments With mprototype only calls to prototyped variable argument functions will set or clear the bit On embedded PowerPC systems assume that the startup module is called sim crt0 o and that the standard C libraries are libsim a and libc a This is the default for powerpc eabisim configurations On embedded PowerPC systems assume that the startup module is called crt0 o and the standard C libraries are libmvme a and libc a On embedded PowerPC systems assume that
108. machine compiler and assembler dependent options and notes Required Compiler Linker Flags The following compiler linker options are required to build for execution on the target CFLAGS none required LFLAGS none required Command Line GDB Debugger Targets e exec Allows loading and including source level browsing of the compiled executable within host memory e remote Allows the GDB to connect to a remote target running the GDB remote debugging protocol via a serial port or a TCP socket connection The GDB debugger can connect to a board via Abatron s BDI2000 or EPI s JEENI JTAG debug agents across Ethernet Any debug agent that communicates using the GDB Stub protocol can be accessed through GDB Visual GDB e extended remote Use a remote computer via a serial line e async Use an executable file as a target e extended async Use a remote computer via a serial line e ddb The GDB communicates with a remote target using the PMON MIPS remote debugging protocol via serial or socket port e lsi The GDB communicates with a remote target using the mips PMON MIPS remote debugging protocol via serial e mips The GDB communicates with a remote target using the MIPS remote debugging protocol via serial or socket port e pmon The GDB communicates with a remote target using the mips PMON remote debugging protocol via serial or socket port e sim The GDB debugger contains a integrated instruction set simulat
109. makefile for the Standard Platform Microcross ships the binary versions of the Linux kernel and libraries to make the evaluation of GX Linux possible without incurring a major investment The actual sources for the Libraries and Linux Kernel along with all the other sources are shipped on the GX Linux CD ROM per GPL requirements however it is up to the user to know how to build the standard products without GX Linux help hence the value add of the Professional Platform Building applications however can be done using the procedure in the next section For those seeking an install and build all out of the box solution the GX Linux Professional Platform is recommended 5 1 1 Building Your Own Applications We assume you already performed at least a preliminary build of the kernel library and root filesystem with BusyBox You can build your own applications load them into rootfs usr bin or any other directory under rootfs and load and run them on the target uSBC 1 Build your application s and name the binary executable with a x file extension recommended 2 Copy your application image file into the lt build directory gt examples directory 3 To install your application into rootfs re build the ROM filesystem and reload the target board via TFTP assuming the target board is powered on and connected to your network issue the following commands Ca lt butig direcrory gt cr S make install apps romfs
110. mc and put on line of code in it to call startlinux with the mmc argument When TFTPing the new script add the eB attribute to autostart Linux with query from uUMON 5 6 6 Writing to On Board Flash via a Compact Flash Card The Compact Flash CF socket on Cogent boards is configured as a mass storage device IDE by default with GX Linux Contact Microcross for information on other options available e g PCMCIA WIFI Wirelss Ethernet etc The compact flash card driver can be mounted with the following command mount dev hdal mnt ct cr Note We have noted in our testing that CF cards 512 MB and larger do not work in the Cogent boards Recommend using 256 MB or smaller memory cards 42 E GX Linux User Guide Section 6 Debugging Applications Section 6 0 Debugging Applications There are two common tools used for symbolic debugging software used in Linux based target hardware The GDB debugger is typically used to debug applications A JTAG emulator is typically used to debug the Linux kernel and kernel device drivers Debugging using a JTAG emulator is dependent on the emulator used and thus is not discussed in this manual 6 1 The GDB Debugger 6 1 1 GDB Debugger The purpose of a debugger is to allow the developer to see what is going on inside his her program while it executes Two debuggers are provided in the GX Linux BSP and they are located in usr bin the toolhames are lt target alias g
111. mes end with s in place of the source file s c assembly As we have seen running with c produces object files whose names end with o We have just finished a long discussion of the many kinds of input that the compiler takes and the different kinds of output that it can provide Pictures are not always worth a thousand words particularly when it comes to summarizing a lot of disparate information But it may help you to remember this information if you view the compiler as a kind of machine with different inputs and outputs as outlined earlier 56 E GX Linux User Guide Section 9 How to Use GNU X Tools The input file s name determines where it goes into the machine The c S cc cpp and C files go to the preprocessor i and ii files go straight to the compiler and so on Compilation options determine which stage of the machine produces output i e how many stages of the machine you run The S means that you stop after the assembler and the output filename ends with s If you keep this picture in mind the compilers machinations will not seem so strange you will stop seeing preprocessing compilation assembly and linking as separate steps and come to see compilation as one big assembly line for which ccc is the production manager The following tools listed in Tables 9 2 9 3 and 9 4 are the main tools for developing projects with a GNU X Tools Toolsui
112. nd line If you use 1d as a linker you need to mention these libraries explicitly 9 9 1 Invoking Id The rules for invoking 1d if you must do so are the same as for GCC or as The basic 1d command is as follows lt target alias gt ld lt list of options gt lt list of files and libraries gt cr Where list of files and libraries is a series of filenames and library specifications To include a library in this list use the notation 1name where the name of the library file is either lib libname a or usr lib libname a The linker processes the list of files and libraries in order When it reaches a library it extracts only those modules that it currently needs to resolve external references Consequently the position in which libraries appear in this list is important For example the command lt target alias gt gt id progl o Im prog2 6 cr results in an Undefined symbol message if prog2 o0 refers to any programs in the library usr lib libm a unless you happen to be lucky and prog2 0 only uses routines that the linker extracted for the sake of prog1 o Note that libraries may refer to other libraries thus the command lt targer alaas gt o ld prog1 0 lat lio cr leads to Undefined symbol messages if the fo library requires any routines from at This situation is more complex for a user generated library Such a library should contain an in
113. nd now desire to remove the installed tools 6 xtools remove all go path prefix The remove all command allows the user to summarily remove all toolsuites from the system With the exception of the files usr bin xtools usr bin xtools rc and etc profile Cygwin only this command affects a complete removal of GNU X Tools toolsuite binaries from your system 7 xtools install libs lt target alias gt arcpath This option allows an administrator to update or reinstall toolsuite libraries only This feature is useful for selectively reinstalling libraries that have been over written or updating the libraries from a newer toolsuite version without updating the entire toolsuite It updates the following files usr lt target alias gt lib libc a usr lt target alias gt lib libstdct t a It extracts the library files from a Microcross GNU X Tools Toolsuite distribution CD ROM or filesystem image The optional arcpath parameter may be used to locate the update files Note This feature is currently experimental and may change 8 xtools install hdrs lt target alias gt arcpath This option like option 7 allows incremental updates to an installed toolsuite except that it updates the library headers files It updates the following files usr lt target alias gt include h 9 3 Invoking GNU X Tools To invoke GNU X Tools from the command line in the shell type xtools target alias
114. nd tells Gcc to look for libraries first in src local lib path then in the standard location If someone has put a local version of a library in src local lib that version is used in preference to the standard version in usr lib The 1m specifies the library name actual library name is libm a The prefix and suffix to the library name can be dropped on all library names The naming convention for GNU libraries is lib lt name of lib gt a static libs and lib lt name of lib gt so shared libs Unix Linux linkers search libraries in the order in which they occur on the command line and only resolve the references that are outstanding at the time the library is searched Therefore the order of libraries and object modules on the command line can be critical this is why 1 options come after the filenames Consider the command lt target alias gt 9 gcc L mine Tirst c cr This command searches for the library file libmine a to resolve any function references needed for linking however the linker has not yet processed the object module for file4 o created by the GCC command and normally deleted if compilation and linking are successful Therefore there are no outstanding function references and the library search has no effect If the program needs this library the GCC command produces Undefined symbol messages during the loading phase and the linker does not produce an execu
115. ndard error output the commands executed to run the stages of compilation Also print the version number of the compiler driver program and of the preprocessor and the compiler proper Like v except the commands are not executed and all command arguments are quoted This is useful for shell scripts to capture the driver generated command lines pipe Use pipes rather than temporary files for communication between the various stages of compilation This fails to work on some systems where the assembler is unable to read from a pipe but the GNU assembler has no trouble help Print on the standard output a description of the command line options understood by gcc If the v option is also specified then help will also be passed on to the various processes invoked by gcc so that they can display the command line options they accept If the Wextra option is also specified then command line options which have no documentation associated with them will also be displayed target help Print on the standard output a description of target specific command line options for each tool version Display the version number and copyrights of the invoked GCC Uname Some symbols usually those identifying the type of computer system you re compiling on are automatically defined by the compiler If you want to suppress one of these symbols use the Uname option This is equivalent to putting un
116. nerate code that does not use uses the floating point register mhard Loart set Software floating point emulation is provided if you use the msoft float option and pass the option to GCC when linking The default setting is hardware floating point mmultiple Generate code that uses does not use the load multiple word mne multtple instructions and the store multiple word instructions These instructions are generated by default on POWER systems and not generated on PowerPC systems Do not use mmultiple on little endian PowerPC systems since those instructions do not work when the processor is in little endian mode The exceptions are PPC740 and PPC750 which permit the instructions usage in little endian mode mstring Generate code that uses does not use the load string mno string instructions and the store string word instructions to save multiple GX Linux User Guide E 95 Appendix 3 GNU X Tools PowerPC Linux Toolsuite Option Description gt gt O registers and do small block moves These instructions are generated by default on POWER systems and not generated on PowerPC systems Warning Do not use mstring on little endian PowerPC systems since those instructions do not work when the processor is in little endian mode The exceptions are PPC740 and PPC750 which permit the instructions usage in little endian mode mupdate Generate code that uses does not use the load or store mno updat
117. ng an Ethernet cross over cable To get the target board booted up and communicating with your host Linux computer you will need to configure your serial port and MicroMonitor before loading GX Linux binaries Step 1 Setup Serial Terminal e If you do not have a serial terminal program running on your host machine you will need to install one We recommend a serial terminal program such as minicom or similar e Connect the Cogent provided null modem serial cable to the target board and host computer e Configure your serial terminal program to connect to the target board using the following settings 38400 baud 8 data bits No parity 1 stop bit no flow control e Connect power supply to the board and the serial terminal should show the MicroMonitor startup banner and the UMON gt command prompt Figure 3 2 Diagram of Board Connections to Host Computer Keyboard Mouse Monitor AC Power Ethernet cross over cable COM1 ETHO ttySO Host Development Computer Step 2 Setup uMON Null modem serial cable Serial 0 Ethernet Cogent CSB6xx 9xx 42VDC Power Target Board P S AC Power You have two options to setup the network file monrc in MicroMonitor manual settings and DHCP BootP Consult your system administrator if you need help in determining your network settings GX Linux User Guide E 23 Section 3 Getting Started Manual network
118. nit The lt target alias gt gdb gdbtk debuggers will read an optional gdbinit when they are started For either gdbserver network or serial connection the corresponding set of GDB commands can be defined as a macro within your gdbinit to simplify these steps Consider the following sample gdbinit define target remote set endian little target remote x x x x 2001 end With this macro defined in your gdbinit file GDB can be connected to the remote gdbserver with the single command gab Carget remote 46 m GX Linux User Guide section 7 Networking 7 0 Networking 7 1 Default Kernel Configuration with Networking Enabled The GX Linux BSP ships with a default kernel configuration that has networking enabled With the supplied default configuration you will only need to use the uMON to set networking values appropriate for your network After connecting the target hardware to a LAN and booting the kernel you should be able to use the network The UMON passes the network settings to the Kernel via the startlinux script For example commands like the ones given below should be immediately available to you t ifconfig er t route cr ping lt known network IP address gt cr E e e E 7 2 Network Configuration The network is automatically configured to mimic the settings in uMON when GX Linux boots however for modification or adding a second Ethernet configuration for those targets with dual Ethernet
119. nstalled into the target file system by simply copying them into the appropriate sub directories under gxlinux rootfs The target file system is built by default as a compressed romfs img file system using genromfs 5 4 1 Adding Content to the Target File System You can configure the target file system with additional content not included in the BSP s default target file system The following steps illustrate two methods that can be used to put new applications into the target file system In these illustrations the application is the Hello World example 1 The following steps compile and install the Hello World example into the target file system image on the Linux development workstation S cd lt build directory gt examples hello cr S make apps install apps romfs cr 38 E GX Linux User Guide Section 5 Making Modifications to GX Linux The make romfs img target command creates the target file system image as lt build directory gt romfs img which is the file we downloaded to the target hardware using the UMON bootloader 5 5 Putting the New System on the Target Hardware 5 5 1 Putting the New System on the Target Hardware Once you have created a new BSP component a new kernel image a new file system image and the uMON startlinux script the uMON bootloader can be used a to download the components into the target hardware s SDRAM b to save the component in FLASH memory and or c to b
120. nstructions that it will generate based on the CPU specified by a mcpu option For some arm implementations better performance can be obtained by using this option march lt name gt This specifies the name of the target ARM architecture GCC uses this name to determine what kind of instructions it can use when generating assembly code This option can be used in conjunction with or instead of the mcpu option Permissible names are armv2 armv2a armv3 armv3m armv4 the default setting armv4t armv5 and armvote This specifies the version of the floating point emulation available on 78 E GX Linux User Guide Appendix 1 GNU X Tools ARM Linux Toolsuite Option si Description the target Permissible values are 2 and 3 mfp is a synonym for mfpe to support older versions of GCC The size of all structures and unions will be rounded up to a multiple of the number of bits set by this option Permissible values are 8 and 32 The default value varies for different toolsuites For the COFF targeted toolsuite the default value is 8 Specifying the larger mstructure size boundary lt n gt number can produce faster more efficient code but can also increase the size of the program The two values are potentially incompatible Code compiled with one value cannot necessarily expect to work with code or libraries compiled with the other value if they exchange information using structures o
121. ntly in flash Such applications will require extensions to the target hardware to allow hosting of a read write flash file system These extensions will include e Provision of a writable flash file system that the kernel can mount on bootup Writable flash file systems are available under the 2 6 kernel ext2 ext3 JFFS JFFS2 VFAT etc These flash file systems are well documented and discussed in the Linux Open Source embedded systems community e Kernel configuration changes for example via make xconfig or menuconfig to enable the particular file system type used e Addition of an underlying flash media access layer driver to support the board s flash chip s or external compact flash pendrive or USB drive To mount a pendrive using the standard configuration of GX Linux and USB host Insert the pen drive and the operating system will echo the mount point issue the following command mount t vfat dev sdal mnt pendrive cr or alternatively mknod var sdal b 8 1 mount t vfat var sdal mnt pendrive for a standard ext filesystem issue the following command mount dev sdal mnt pendrive cr or alternatively mknod var sdal b 8 1 mount var sdal mnt pendrive After mounting the pen drive you can change to this drive or copy files to it using the mount point mnt pendrive Use the umount mnt pendrive command to un mount the drive 5 6 4 How to Prepare a Pendrive with a Root Filesystem an
122. ntrol over your executable file by writing a linker script If you have a thorough knowledge of your target machine s architecture you may be able to use this to your advantage though you will probably reach the point of diminishing returns fairly quickly 9 9 5 The C Runtime crt0 To link and run C or C programs you need to define a small module usually written in assembly as crt0 s but sometimes written as a C file as crt0 c to initialize hardware using C conventions before calling main There are some examples available in the sources of Newlib C library perform a simple search through the source tree for crt0 s code as well as examples of system calls with sub routines To write your own crt0O s or crt0 c module you need specific information about your target see MC Embedded Systems pdf in the GNU X Tools CD docs directory also in Cygwin docs for details on how to create the C runtime environment 9 10 Object Translation ELF to Binary SREC etc Most of the GNU X Tools toolsuites produce an Extended Linker Format ELF object file as the default format and it can be used during debug and testing however the final code needs to be stripped and translated to another GX Linux User Guide E 73 Section 9 How to Use GNU X Tools format It is beyond the scope of the user guide to explain all of the various formats which include COFF ECOFF binary srec tekhex inex symbolsrec
123. nux User Guide Section 3 Getting Started 3 4 MicroMonitor Boot ROM Familiarity and Tips MicroMonitor is the boot ROM that comes with each Cogent development board It is very useful in initializing hardware starting serial and Ethernet services and creating a tiny filesystem to store the embedded Linux startup binaries Moreover MicroMonitor facilitates loading the GX Linux binaries using TFTP services or XModem through the serial port We will focus on the TFTP across Ethernet transfer solution due to the size of the images and time it takes to load binaries 3 4 1 Manual TFTP Up Load Procedure Microcross ships each board pre configured with the Linux script startlinux and two binaries zImage kernel and romfs img root filesystem and Busybox utilities To up load your newly created versions follow the steps in this section The up load address lt target ftp address gt is that of the target board Reload startlinux Startup Script To reload startlinux script on the target board you have three options to control your linux bootup 1 Load startlinux for manual bootup requires serial connection to use the UMON command line interface to execute startlinux y S cd sbuild dir bDoot S ttftp lt target ftp address gt put startlinux startlinux e 2 Load startlinux for autoboot with abort query Cd lt builbe dir bc6e S ttftp lt ftp address gt put startlinux startlinux eB
124. ols static link is the default setting shared If shared libraries are available use them wherever possible rather than static libraries When used with GCC add the correct option wWl shared I dir Add the directory dir to the head of the list of directories to be searched for header files This can be used to override a system header file substituting your own version since these directories are searched before the system header file directories If you use more than one I option the directories are scanned in left to right order the standard system directories come after I Any directories you specify with 1I options before the I option are searched only for the case of tinclude file they are not searched for include lt file gt If additional directories are specified with 1I options after I these directories are searched for all include directives Ordinarily all I directories are used this way In addition the I option inhibits the use of the current directory where the current input file came from as the first search directory for include file There is no way to override this effect of I With I you can specify searching the directory that was current when the compiler was invoked That is not exactly the same as what the preprocessor does by default but it is often satisfactory I does not inhibit the use of the
125. ols with an example Embedded Linux program for the Cogent CSBxxx The example shown can be replicated for any of the other examples described below The example program was created with the Visual X Tools wizard and is available only with the professional platform or a separate purchase of the Visual X Tools IDE for either Windows or Linux host operating systems 4 1 Hello Example Program This section briefly goes over the standard hello world program that talks to the console via libc xflat so using printf statements Step 1 Startup Visual X Tools IDE from a desktop icon or Bash xterm shell See the Visual X Tools IDE icon in Figure 4 1 igual Tools Figure 4 1 Visual X Tools IDE Icon Step 2 Click on Project Open Workspace fromthe menu Navigate to the following directory lt build directory gt examples vxtools hello Open the workspace file hello vxw and go onto the next step Step 3 On the Visual X Tools menu click on Build Set Active Configuration and select either Debug or Release Step 4 On the Mini Toolbar see Figure 4 2 click on Clean amp Build Project icon ks Compile Clean Build Clean amp Run GHOU Windows Visual GOB Clear Binaries Project Build Debugger Bash Shell Command Debugger Process Butt Figure 4 2 Mini Toolbar Description GX Linux User Guide E 33 Section 4 Visual X Tools Example Application Project These commands are also located und
126. olsuite comprises a complete development environment for the PowerPC processor family Included in this section of the Appendix are the required compiler and linker flags a list of debugger targets for both command line GDB and Visual GDB machine compiler and assembler dependent options and notes Required Compiler Linker Flags The following compiler linker options are required to build for execution on the target CFLAGS none LFLAGS none Command Line GDB Debugger Targets e async Use a remote computer via a serial line e Cisco Use a remote machine via TCP e dink32 The GDB debugger communicates with a remote target processor running the DINK32 monitor e exec Allows loading and including source level browsing of the compiled executable within host memory e extended async Use a remote computer via a serial line e extended remote Use a remote computer via a serial line e remote Allows the GDB to connect to a remote target running the GDB remote debugging protocol via a serial port ora TCP socket connection The GDB debugger can connect to a board via Abatron s BDI2000 or EPI s JEENI JTAG debug agents across Ethernet Any debug agent that communicates using the GDB Stub protocol can be accessed through GDB Visual GDB e ppcbug The GDB debugger communicates with a remote target processor running the PowerPC PPCBug monitor on port 0 e ppcbugl The GDB debugger communicates with a remote target proce
127. on the GNU X Tools CD ROM The O Reilly book Programming with GNU Software by Mike Loukides and Andy Oram is highly recommended being complementary to this User Guide as well as a comprehensive guide to the GNU tools The remaining texts provide more in depth knowledge for specific toolsuite components as needed In addition Microcross offers a GNU X Tools Training Guide as a complimentary product It is based on an on site three day training course for beginning to intermediate level audiences The course material is tailored to the GNU X Tools for embedded development and the format is geared to a self paced training program 9 2 Using the GNU X Tools Command Line Tool xtools The GNU X Tools command line tool is a shell tool designed to provide several functions that facilitate convenient management of the GNU X Tools cross toolsuites from a command shell environment For many developers this method is more convenient than using a GUI The following functions may be invoked from any Bash Shell prompt 1 xtools enter Execution of the xtools command without arguments will show an abbreviated help screen that summarizes the command options described in this section In addition execution of an incomplete command insufficient or incorrect arguments will produce a help dialog for that command 2 xtools lt target alias gt This command starts a new bash shell having the appropriate environment variables and aliases initial
128. onventions Argument registers a0 a4 aliased to r0 r4 Returned value regs vl v6 aliased to r4 r9 Addressing Modes rn in the following refers to any of the numbered registers but not the control registers 82 E GX Linux User Guide Appendix 1 GNU X Tools ARM Linux Toolsuite addr Absolute addressing mode rn Register direct srn Register indirect or indexed Srn n Register based with offset imm Immediate data Machine Dependent Directives arm Assemble using arm mode thumb Assemble using thumb mode code16 Assemble using thumb mode code32 Assemble using arm mode force thumb Force thumb mode even if not supported thumb func Mark entry point as thumb coded force bx entry ltorg Start a new literal pool Opcodes For detailed information on the machine instruction set see this manual ARM Architecture Reference Manual Addison Wesley ISBN 0 201 73719 1 Here is a recommended book to get a lot of system developer information on the ARM architecture ARM System Developer s Guide Morgan Kaufmann Publishers ISBN 1 55860 874 5 alk paper authors Andrew N Sloss Dominic Symes Chris Wright 2004 NOTES amp ERRATA GX Linux User Guide E 83 Appendix 2 GNU X Tools MIPS Linux Toolsuite Appendix 2 GNU X Tools MIPS Linux Toolsuite cae mips linux for Big Endian and mipsel linux for Little APPROX INSTRUCTION THROUGHPUT Pipelined concurrent PIPELINED FP INSTRUCTIONS Yes IEEE 7
129. oot ROM Familiarity and Tips 18 mE GX Linux User Guide Section 3 Getting Started 3 1 Getting Started with the Standard Platform Linux Host Board Connection and Initial GX Linux Bootup Make physical connections per the diagram layout in Figure 3 1 If connecting to a hub on a network disregard connecting an Ethernet cross over cable To get the target board booted up and communicating with your host Linux computer you will need to configure your serial port and MicroMonitor before loading GX Linux binaries Step 1 Setup Serial Terminal e If you do not have a serial terminal program running on your host machine you will need to install one We recommend a serial terminal program such as minicom or similar e Connect the Cogent provided null modem serial cable to the target board and host computer e Configure your serial terminal program to connect to the target board using the following settings 38400 baud 8 data bits No parity 1 stop bit no flow control e Connect power supply to the board and the serial terminal should show the MicroMonitor startup banner and the UMON gt command prompt Figure 3 1 Diagram of Board Connections to Host Computer Keyboard Mouse Monitor AC Power Ethernet cross over cable COM1 ETHO ttySO Host Development Computer Step 2 Setup uMON Null modem serial cable Serial 0 Ethernet Cogent CSB6xx 9xx 42V
130. oot the new system The steps below describe the general procedure to accomplish this See the UMON documentation or Section 3 of this User Guide for more detailed instructions 1 Power cycle the target hardware Start your serial terminal that is connected to the target board and if configured correctly you should get the UMON prompt 2 From xterm Bash shell change to the build directory and issue make load to download the new kernel file system and startlinux script to the TFS 3 Issue the startlinux script on the UMON command line in the serial terminal The startlinux script is a UMON script that executes the required UMON commands to boot the Linux kernel with the right configuration The configuration values in startlinux were auto generated by the GX Linux BSP Configuration Tools according to the values selected using the BSP configuration tool The Linux kernel and file system image must have been saved to TFS prior to executing the startlinux script Further the startlinux script will require that the Linux kernel and file system image have the same names in TFS as they did on the Linux workstation The startlinux script should be stored on TFS with the executable script attribute enabled the make load command automatically handles this 5 6 Read Only and Read Write File Systems 5 6 1 ROMFS File System The default file system used in the GX Linux BSP is not a permanently writa
131. or based target that can load and execute compiled programs Visual GDB Debugger Targets e Cisco Serial Cisco TCP DDB Serial DDB TCP MIPS Serial MIPS TCP PMON Serial PMON TCP Remote Serial Remote TCP Simulator GBDserver Serial GDBserver TCP This toolsuite comprises a complete development environment for the mips elf processor family This toolsuite configuration has not been successfully tested with mips3 64 bit code generated by the compiler Recommend using Microcross MIPS64 Toolsuite Compiler Machine Dependent Options Section 3 describes all of the common compiler linker and assembler options used in Microcross GNU cross tools in addition these m options are defined for the MIPS family of computers GX Linux User Guide E 85 Appendix 2 GNU X Tools MIPS Linux Toolsuite march arch mtune arch mips1 mips 2 mips3 mips4 mips32 m1 ps32rz2 mips64 mi ps LG mno m1ps 16 mabi 32 mabicalls mno abicalls mxgot mno xgot 86 mE GX Linux User Guide Generate code that will run on arch which can be the name of a generic MIPS ISA or the name of a particular processor The ISA names are mips1 mips2 mips3 mips4 mips32 mips32r2 and mips64 The processor names are 4kc 4kp 5kc 20kc m4k r2000 r3000 r3900 r4000 r4400 r4600 r4650 r6000 r8000 rm7000 rm9000 orion sb1 vr4100 vr4111 vr4120 vr4300 vr5000 vr5400 and vr5500 The special value from abi selects th
132. parameters for machine type cpu type butdo not set the architecture type register usage or choice of mnemonics as mcpu cpu type would The same values for cpu_type are used for mtune as for mcpu If both are specified the code generated will use the architecture registers and mnemonics set by mcpu but the scheduling parameters set by mtune These switches enable or disable the use of built in functions that allow access to the AltiVec instruction set You may also need to set mabi altivec to adjust the Appendix 3 GNU X Tools PowerPC Linux Toolsuite Option Description S Po current ABI with AltiVec ABI enhancements mabi spe Extend the current ABI with SPE ABI extensions This does not change the default ABI instead it adds the SPE ABI extensions to the current ABI Disable Booke SPE ABI extensions for the current ABI instructions simd instructions mfloat gprs yes no This switch enables or disables the generation of floating point operations on the general purpose registers for architectures that support it This option is currently only available on the MPC8540 mrul Toc Modify generation of the TOC Table Of Contents which is mn6 ip in toc created for every executable file The mfull toc option is mno sum in toc selected by default In that case GCC will allocate at least one mminimal toc TOC entry for each unique non automatic variable reference in your program GCC will also place flo
133. pied into the root filesystem usr bin Directory of the pre built kernel zimage file varetc Directory contains the filesystem etc and var directory contents the etc directory contains a the system configuration files for the host and the var directory contains logs lock files and process specific data files Table 2 3 shows the source directory contents with all of the source files that come with GX Linux The only file that is needed to install however is gxlinux lt ver gt lt csbxxx gt bin tar gz and the next step shows how to install this tarfile Table 2 3 Source Directory src on CD ROM Source File Name Tar file contains the BusyBox source tree Tar file contains the configuration files for the BSP examples tar gz Tar file contains 20 example programs that get built and added to usr bin dir in the ROM filesystem GX Linux Standard Platform BSP with Build directory Tar file of filesystem elements that include the etc and var dirs Step 8 Browse the CD ROM src directory to get the complete filename format is gxlinux lt ver gt lt csbxxx gt bin tar q7 Example Installing GX Linux BSP e Open an xterm Bash shell e Mount the GX Linux CD ROM if it is not already mounted e Issue the following commands to create a build directory S cd home lt user name gt cr other other install directory tar xvzf min cdrom src gxlinux 0 j1 csbo3 bin tar 6gz
134. pload procedures above you can add the zImage Linux kernel to the TFS on uMON Ss cd lt directory lLinux zImage binary gt S ttftp lt target ftp address gt put zImage zImage Reload romfs img Procedure Similarly to the upload procedures above you can add the romfs img root filesystem and Busybox utilities to the TFS on uUMON cd lt build directory gt S ttftp lt ftp address gt put romfs img romfs img To rebuild any component of this BSP refer to Section 5 for details 3 4 2 Other Useful MicroMonitor Commands uMON gt tfs ls List files in the Tiny File System uMON gt tfs clean Defrag the Tiny File System without deleting files uMON gt tfs init Delete all files and defrags the Tiny File System requires network setup uMON gt tfs rm lt file name gt Delete a specific file named lt file name gt uMON gt help Shows all of the available commands uMON gt help lt command name gt Shows specific help on command name uMON gt set Shows all settings in memory uMON gt flash info Shows all flash sectors and which ones are locked and erased uMON gt flash unlock x y Unlocks sectors x lower bound to y upper bound uMON gt flash erase x y Erase sectors x lower bound to y upper bound 32 E GX Linux User Guide Section 4 Visual X Tools Example Application Project Section 4 0 Visual X Tools Example Application Project The following steps describe the operation of the Visual X To
135. project because the IP address is a key parameter to your TFTP communications between the host development platform and the target board Step 3 Modify Environment Variables Open Visual X Tools or another editor and edit the master Makefile in the build directory The build directory is gxlinux directory created at installation time Edit configuration variables as follows ARCH lt arch of target gt i e arm mips ppc etc BOARD lt csbxxx gt if not set enter the Cogent uSBC name e g csb637 csb625 etc TGTIP lt IP address gt enter the IP address assigned to the target board in the last step Optionally you can modify the other configuration variables that apply but the three most important are the ones above Step 4 Make All Start an xterm Bash shell change directory to the build directory and issue the following command make all cr the system configures and builds everything for the target board 24 E GX Linux User Guide Section 3 Getting Started If there are any build or install errors make sure the toolsuite and BSP were installed correctly per instructions in Section 2 If you still have problems contact Microcross support at 1 478 953 1907 or support microcross com Step 5 Load Binaries and Startup Script This step assumes that the target board is powered up connected to Ethernet and uMON prompt is displayed in a serial terminal From the build directory in xterm Bash issu
136. ptions filelso a 12eN 0o o program All alternatives actually look the same to the compiler parts The program executed under the name of GCC is just a front that handles options and temporary files and calls the real compiler parts cpp the C preprocessor It takes care of preprocessor directives such as include files and macro expansions It also removes comments The result is a file with the C code lots of white space and some line numbering directives that the compiler core can use in warning and error messages The o filter argument tells GCC to name the executable file program If you don t specify an o argument GCC chooses the default name a out which is not particularly informative and would cause multiple executables to overwrite each other So most programmers use the o argument to name the program Since the inputs to the last example above are all object files no compilation or assembly is required GCC always invokes the linker Using Gcc to invoke the linker is preferable to using 1d separately because GCC ensures that the program is linked with the correct libraries and initialization routines 9 5 1 GCC Options Commonly Used Compile or assemble the source files but do not link The linking stage simply is not done The ultimate output is in the form of an object file for each source file o file The o and not c tells GCC to create a linked executable with a user defin
137. r unions Programmers are encouraged to use the 32 value as future versions of the toolsuite may default to this value noretu ri function It will be executed if the function tries to return mlong calls Tells the compiler to perform function calls by first loading the mno long Ca l Ls address of the function into a register and then performing a subroutine call on this register This switch is needed if the target function will lie outside of the 64 megabyte addressing range of the offset based version of subroutine call instruction Even if this switch is enabled not all function calls will be turned into long calls The heuristic is that static functions functions which have the short call attribute functions that are inside the scope of a pragma no long calls directive and functions whose definitions have already been compiled within the current compilation unit will not be turned into long calls The exception to this rule is that weak function definitions functions with the long call attribute or the section attribute and functions that are within the scope of a pragma long calls directive will always be turned into long calls This feature is not enabled by default Specifying no long calls will restore the default behavior as will placing the function calls within the scope of a pragma long calls off directive Note these switches have no effect on how the compiler generates code to handle
138. re e 38400 baud e 8 data bits e no parity e 1 stop bit The default dev ttyS1 settings are e 38400 baud e 8 data bits e no parity e 1 stop bit 8 5 Kernel Console over Serial Default Configuration In the make xconfig you will encounter the option Console on Amtel AT91RM9200 serial port This feature is enabled by default This is what allows the internal kernel messages to appear over the serial line and therefore on your remote connected terminal session such as Minicom Recall that printk is NOT the same as printf e printk is only performed within the kernel itself for various diagnostics and OS warning messages e _printf is used by applications in user space for general console output The setting we use here only applies to the kernel printk messages 50 m GX Linux User Guide Section 9 How to Use GNU X Tools Section 9 How to Use GNU X Tools 9 1 Introduction This section is intended to provide an abbreviated overview of using the GNU compiler and tools to generate executable programs for a target processor Mastering the toolsuite and using it to develop embedded systems on a practical scale requires greater in depth knowledge than can be covered here If you are considering the GNU cross tools for full scale development it is suggested that you acquire the manuals listed in the bibliography see Bibliography The ones having unrestricted reproduction rights are included in the docs directory
139. register Spor Addressing Modes rn in the following refers to any of the numbered registers but not the control registers addr Absolute addressing mode orn Register direct Sin Register indirect also called register based expr Srn Register based with offset Srx rn Register based with register offset imm Immediate data Machine Dependent Directives set mipsn Changes MIPS architecture level during assembly n 1 2 3 4 set mips0 Reverts MIPS architecture level to invocation value set mipsl6 Changes to MIPS 16 mode Assembles MIPS 16 instructions set nomipsl6 Revert to normal 32 bit mode insn Marks code emitted by data directive as an instruction sets Isb Useful for MIPS16 code segments rodata sbss MIPS supports some additional sections besides the usual text data and bss The additional sections are rodata used for read only data sdata used for small data and sbss used for small common objects The assembler uses the Sgp 28 register to form the address of a small object Any object in the sdata or sbss sections is considered small in this sense For external objects or for objects in the bss section you can use the GCC G option to control the size of objects addressed via S gp the default value is 8 meaning that a reference to any object eight bytes or smaller uses Sgp Passing G 0 to as prevents it from using th
140. rent directory with their original names Normally the timestamp of the extracted files is the time at which ar recreated them If you use the option xo instead of x ar sets the timestamp of the extracted files to the time recorded in the archive You can still create an ordered index less library with ar and invoke ranlib as a separate step if you want which is the convention of older Unix Systems However there is no longer any good reason for doing that when using GNU tools 9 12 GNU Libraries If you are familiar with Unix Linux and C programming the libraries you will find in the GNU X Tools development environment should not confuse you The libraries you expect will all be there standard I O the math library the strings library etc The libraries are ANSI C and POSIX compliant Moreover there are many functions that Unix Linux programmers expect but are not specified by either of these standards Some C functions have been standardized and found in the GNU environment but system calls and math libraries are not the same as those found in a typical DOS Windows environment You will have to re learn these functions A good resource for learning the GNU Libraries is on the GNU X Tools CD Docs directory Mc Libraries pdf and Math lib pdf GX Linux User Guide E 75 Appendix 1 GNU X Tools ARM Linux Toolsuite Appendix 1 GNU X Tools ARM Linux Toolsuite MODEL target alias ARM Advanced RI
141. rocessing i e M implies E This option can make it much easier to generate correct makefiles aC The preprocessor normally deletes all comments from the program With c it doesn t This flag may be useful in conjunction with E when you are trying to make sure that the preprocessor is doing what you intended In such cases leaving you comments in may be handy The c option doesn t automatically imply E but GCC wont let you use C on the command line unless E is also present 9 7 4 Options to Specify Libraries Paths and Startup Files The following options are common for embedded developers but not in native environments nostartfiles Don t use the standard system startup files when linking Normally the crt0 o file gets linked in as the standard start file however most embedded developers will need to replace the standard start file with a custom start file When used with GCC add the correct option Wl nostartfiles and add the custom startfile with appropriate entry symbol to the linker script e g ENTRY start To learn more about how to create linker scripts and startfiles read the GNU X Tools Training Guide or the Microcross Visual X Tools User Guide nodefaultlibs Do not use the standard system libraries when linking Only the libraries you specify will be passed to the linker The standard startup files and used normally unless nostartfiles
142. rocessor GCC will use only the instructions in the common subset of both architectures and will not use the MQ register GCC assumes a generic processor model for scheduling purposes mcpu power mcpu power2 mcpu powerpc and mcpu powerpc64 specify generic POWER POWER2 pure 32 bit PowerPC i e not MPC601 and 64 bit PowerPC architecture machine types with an appropriate generic processor model assumed for scheduling purposes The other options specify a specific processor Code generated under those options will run best on that processor and may not run at all on others The mcpu options automatically enable or disable the following options maltivec mhard float mmftcrf mmultiple mnew mnemonics mpower mpower2 mpowerpco4 mpowerpc gpopt mpowerpc gfxopt mstring The particular options set for any particular CPU will vary between compiler versions depending on what setting seems to produce optimal code for that CPU it doesn t necessarily reflect the actual hardware s capabilities If you wish to set an individual option to a particular value you may specify it after the mcpu option like mcpu 970 mno altivec On AIX the maltivec and mpowerpc 4 options are not enabled or disabled by the mcpu option at present since AIX does not have full support for these options You may still enable or disable them individually if you re sure it ll work in your environment Set the instruction scheduling
143. s 2 15 arm linux ld GNU linker Id arm linux addr2line Converts addresses to file names amp line arm linux ar Creates object code archives arm Linux Goov Test coverage program for analysis arm linux nm Lists symbols from object files arm linux obj copy Copies and translates object files arm linux objdump Displays information from object files arm ux an lab Generates index to archive contents arm linux readelf Displays information about ELF objects arm linux size Lists file section sizes and total sizes arm linux strings Lists printable strings from files Arm Ti nuxssteip Strips debug symbols from binaries arm linux gdb GDB debugger arm linux gdbtk Visual GDB arm linux run Instruction Set Simulator uClibc C and Math Libraries 0 9 26 TARGET CPU DEPENDENT INFORMATION This toolsuite comprises a complete development environment for the ARM processor family Included in this section of the Appendix are the required compiler and linker flags a list of debugger targets for both command line GDB and Visual GDB machine compiler and assembler dependent options and notes Required Compiler Linker Flags The following compiler linker options are required to build for execution with the simulator CFLAGS none required LFLAGS none required Compiler Machine Dependent Options Section 3 describes all of the common compiler linker and assembler options used in Microcross GNU X Tools Linux edition in addition these m
144. s Incorporated www cogcomp com Linux documentation including guides and FAQs www linuxdoc org Linux newbie org for new Linux users www linuxnewbie org Linux kernel organization that controls new releases and has archives of old ones www kernel org Memory Technology Device MTD for details on memory Flash devices www linux mtd infradead org Microcross Incorporated www microcross com uClibc static and shared C library www uclibc org 104 m GX Linux User Guide
145. s a R 62 9 7 1 Displaying compiler behavior ccceecccseeeceseeeeeeeeeeeaeeeeceeeeeeeeeeseeeeeeeeeeeseeeeseaeeeseeeeeseeeeesaueesseeesaaeeesanseesees 62 9 7 2 C Language ODt ONS essaiera Er E EEEE E sien AEE 62 9 73 Preprocessor OPTIONS ssanosirsdirsir enirn aE EE EE EE E Aa EAE 63 9 7 4 Options to Specify Libraries Paths and Startup Files ec cccecccceeececeeeeeseeeeseeesseeeeseeeeesaeeeeseeessaes 63 3 5 Debugging and Pronling ONO S csc sncecsntetwasdencbssteasiecnuncatedneons unease dennmund een nonce medddonduna nysabdansdwdece nieces teases 65 9 7 0 ODUIIZAT OM ecedcdeciecnetseredce ncitensaeornsiecae mactenscen cniseniencal a cneisauenayianaeedee ak acinscbcar szassipaacshawsds cise we ceusniiendebacnewnedeeyenssareceee 66 9 7 7 Passing Options to the Assembler or LINKe cccccccssseeeceesseeceeseeeceeueeceeseecseaseeessageeessageeessegseeeees 67 9 8 Using the GNU ASSOMDIE ccccscecccceeseeeccesseeccaneeccsaeeecseaseeessaueeecsageeeceaeeesssaeeessaeeececsusesessageeessageeesseass 67 3 9 Using NE LINKET ooir its eet Sno cctnd ine cepoar ces dlencltfaa dethrone essary Siew Ge veiemewetid uw eine won eae cefreemene deimalean yore neon 70 LIT AN OMIA NG tach E seh ore ne Haw dens deposed cele na chow mer EE E E EE A T E 70 OZ MEINE ONIONS cetera E dais nese E dae pepsin det meets ape dines A AN sie EE EEE E EE 71 EERS MEIN CUS ote cic sce ants detest pine Sede T dines ioe pects die N ieee re dines devs AN Ge
146. sembler is really many assemblers folded into one or many different programs with the same name depending on how you look at it You can usually ignore the assembler the compiler invokes it automatically and is usually able to specify everything the assembler needs to know about your environment In rare cases you may need to ask for an assembly option explicitly in these cases you will need to run the assembler as a separate program or use GCC s Wa option to pass additional options to the assembler The assembler arguments must be separated from each other and the wa by commas For example lt target alias gt s occ c g 0 Wa alhy L file c cr This above example emits a listing to standard output with high level and assembly source Usually you do not need to use this wWa mechanism since many compiler command line options are automatically passed to the assembler by the compiler You can call the GNU compiler driver with the v option to see precisely what options it passes to each compilation pass including the assembler GX Linux User Guide E 67 Section 9 How to Use GNU X Tools Next we discuss what the assembler does We will not discuss the assembly language itself The FSF s documentation explains the general syntax of assembly language but refers you to the vendor s architecture manual for CPU dependent details overall architecture instruction set etc The assembler takes a program writt
147. ssor running the PowerPC PPCBug monitor on port 1 e sds The GDB debugger communicates with a remote target processor running the SDS debugging protocol e sim The GDB debugger contains a integrated simulator based target that can load and execute compiled programs Visual GDB Debugger Targets e Cisco Serial Cisco TCP Remote Serial Remote TCP SDS Simulator GDBserver Serial GDBserver TCP Compiler Machine Dependent Options Section 3 describes all of the common compiler linker and assembler options used in Microcross GNU cross tools in addition these m options are defined for the IBM RS 6000 and PowerPC Option i Description _ _ _ o mcpu cpu_type Set architecture type register usage choice of mnemonics and instruction scheduling parameters for machine type cpu_type Supported values for cpu_type are 401 403 405 405fp 505 601 602 603 603e 604 604e 620 630 740 7400 44250 750 S01 B21 GZs 660 970 Common eco03e G3 G4 G5 power power2 power3 GX Linux User Guide E 93 Appendix 3 GNU X Tools PowerPC Linux Toolsuite Option Description S O M UNGE CPU CrO maltivec mno altivec 94 m GX Linux User Guide power4 powerpc powerpco4 rios riosl rios2 rsc and rs64a Other CPU types may be derivatives of one of the above core architectures mcpu common selects a completely generic processor Code generated under this option will run on any POWER or PowerPC p
148. structions from level 1 of the MIPS ISA This is the default 3000 is the default CPU type at this ISA level Issue instructions from level 2 of the MIPS ISA branch likely square root instructions r6000 is the default cpu type at this ISA level Issue instructions from level 3 of the MIPS ISA 64 bit instructions r4000 is the default CPU type at this ISA level Issue instructions from level 4 of the MIPS ISA conditional move prefetch enhanced FPU instructions r8000 is the default CPU type at this ISA level Equivalent to march mips4 Equivalent to march mips32r2 Equivalent to march mips64 Enable disable 16 bit instructions Generate code for the indicated ABI Emit or do not emit the pseudo operations abicalls cpload and cprestore that some System V 4 ports use for position independent code Lift do not lift the usual restrictions on the size of the global offset table GCC normally uses a single instruction to load values from the GOT While this is relatively efficient it will only work if the GOT is membedded pic mno embedded pic Appendix 2 GNU X Tools MIPS Linux Toolsuite smaller than about 64k Anything larger will cause the linker to report an error such as relocation truncated to fit R MIPS_ GOT16 foobar If this happens you should recompile your code with mxgot It should then work with very large GOTs although it will also be less ef
149. t gdb and lt target alias gdbtk e g arm linux gdb and arm linux gdbtk GDB is the command line debugger and GDBTK is the Visual GDB aka Insight Use of that debugger is the topic of this section For detailed information regarding usage of the GDB debugger please refer to one of the following e The info and standard GDB man pages included on your Linux workstation e The online manual provided by the Free Software Foundation at http www gnu org software gdb documentation e Debugger docs on the GX Linux CD ROM under docs directory 6 1 2 gdbserver The GDB debugger executes on the user s Linux workstation In order to communicate with a program running on the target hardware an additional program must run on the target hardware This program is gdbserver It is included with the GX Linux toolchain and is installed in the target file system as usr bin gdbserver 6 1 3 gdbserver Communications There are two methods for communication between the target hardware s gdbserver and the Linux workstation GDB client One method uses an available serial port while the other uses the Ethernet port Some target hardware have multiple serial connectors with one of them dedicated to the system console typically dev ttyS0 and another dev ttyS1 is available for GDB communication with the Linux workstation In the case where the target hardware has only one serial port it is probably not available for GDB debugging In this case
150. table file To perform this compilation correctly enter the command lt target alias gt s gcc first c Imine cr GX Linux User Guide E 61 Section 9 How to Use GNU X Tools Now the loader searches the library after processing first c and is able to resolve any references requiring this library When compiling a C program you often don t need to list any libraries explicitly on the command line The GCC automatically searches the system call library I O library and run time initialization routines If you use any math routines you ll need to search for the math library 1m if you re compiling C code you need to include the C libraries lstdct 9 7 Compilation Options The following sections discuss other important options that are available with the Gcc There are many many other options perhaps several hundred all together that control various details of compilation and optimization The chances are that you will never need these but it won t hurt to familiarize yourself with the complete documentation for GCC Complete coverage of GCC options is provided in Using and Porting GNU CC reference 20 9 7 1 Displaying compiler behavior The v verbose option prints the compiler s version number and complete details about how each pass is executed This option is particularly useful for finding out exactly which options your program is being linked with 9 7 2 C Language Options We
151. te Table 9 2 GNU X Tools Compiler and Development Tools gdb GNU debugger for source and assembly debugging with commandline Table 9 3 GNU X Tools Libraries Non restricted ANSI C runtime library Newlib for cross development Support library for embedded targets board support for cross development deprecated will be replaced by a future product Table 9 4 GNU X Tools Binary Utilities Utility Description Target Dependent Converts addresses into file names and line numbers Creates modifies and extracts from object code archives diff Comparison tools for text files diff3 sdifTf et E ee Di paye infer natioi abot ELE fornatobjectnos y O The Adobe Acrobat PDF files listed in Table 9 5 are available on the GNU X Tools or Cygwin docs directory CD ROM for reference or hard copy duplication GX Linux User Guide E 57 Section 9 How to Use GNU X Tools Table 9 5 PDF Documentation on CD ROM No FileName Description CSC sC aag a Ss 1 Bencht pdf By Joe Orost Bench is designed to 15 measure the performance of the code generated by C compilers not hardware performance Debugger v3 3 9 15 January 2004 Man pages pdf A Concise Reference Document for all of the Tools in Unix Man Page Format MC Auxiliary Tools pdf Using as Using binutils Using cygwin Using info Using the C Preprocessor MC Debugging Tools pdf Debugging with GDB Insight the GNUPro Debugger GUI Interface
152. tem will announce that it has mounted the CD ROM as read only Note On some Linux systems the CD ROM will be mounted by an automounter which means using mount in step 3 is not required or the procedure may need to be modified to accommodate non standard Linux distributions or a machine with multiple CD ROM drives that have differing naming conventions Step 4 Install the GNU X Tools command tool for the Bash xterm shell by executing the following commands cd cr t tar xvz i mnt cdrom bin rcfiles tgz Cr At this point you should be able to execute the xtools command tool inside of the Bash shell by its name The command xtools cr should invoke the abbreviated tool help screen that shows the basic operating commands see Section 10 for a complete description of the command tool GX Linux User Guide E 13 Section 2 Installation and Setup Step 5 To install the two GNU X Tools toolsuites from the GX Linux CD simply substitute the target alias i e lt target alias gt arm linux mips linux mipsel linux ppc linux arm elf mips elf etc and issue the command xtools install lt target alias gt cr for the first toolsuite xtools install lt target alias gt cr for the second toolsuite These commands will extract the toolsuite tarballs installing all files in their appropriate locations The install command assumes the default archive source path is mnt cdrom bin using mnt cdrom
153. th prefix argument allows the utility to examine the installation state in which the user may have elected to manually install or build install toolsuite s into an alternate location other than usr GX Linux User Guide E 51 Section 9 How to Use GNU X Tools 4 xtools install lt target alias gt archive path This command will install a complete cross toolsuite from the distribution tarball or zipset located on the specified archive path All files are unarchived to the proper location see above regardless of the current directory state and subsequent invocation of a bash shell using the xtools lt target alias gt command will render the toolsuite ready to use If the archive path is not provided a default path is selected The command xtools install will display the default path which is mnt cdrom unless it has been changed or overridden by the global environment variable SXTOOLS ARC PATH 5 xtools remove lt target alias gt path prefix This command allows the user to selectively remove a designated toolsuite from the system In the unusual case where the toolsuite has been manually installed to some root prefix other than usr the second option can be used to specify the root prefix such as usr bin from which removal of all toolsuite files is desired This command is most useful if you have performed a build from sources and subsequent install to an alternate root prefix path a
154. that all functions will start with a recognizable set of instructions or in fact one of a choice from a small set of different function prologues and this information can be used to locate the start if functions inside an executable piece of code The default is msched prolog msoft float This is the default and it is not necessary to specify it The Instruction Set Simulator ISS will only run code generated with the default software floating point emulation Software floating point is the default Generate code for a processor running in little endian mode This is the default for all standard configurations Big endian is not supported with this toolsuite malignment traps Generate code that will not trap if the MMU has alignment traps enabled On ARM architectures prior to ARMv4 there were no instructions to access half word objects stored in memory However when reading from memory a feature of the ARM architecture allows a word load to be used even if the address is unaligned and the processor core will rotate the data as it is being loaded This option tells the compiler that such misaligned accesses will cause a MMU trap and that it should instead synthesize the access as a series of byte accesses The compiler can still use word accesses to load half word data if it knows that the address is aligned to a word boundary This option is ignored when compiling for ARM architecture 4 or later since these processors
155. the Ethernet port should be used for GDB communication with the Linux workstation If you are going to use the serial port for debugging see the 6 4 Changing Serial Port Settings section for additional information about the use and configuration of the board s serial port Use the connection that is appropriate for your target hardware specifying it at the time you start the debug session 6 1 4 Graphical Front Ends If you would like to use a graphical front end with arm linux gdb there are several compatible front ends available One popular front end is the ddd utility http Awww gnu org software ddd Below is an example of how you would invoke the ARMY arm linux gdb debugger using the ddd graphical front end S ddd debugger arm linux gdb cr GX Linux User Guide E 43 Section 6 Debugging Applications 6 1 5 Debug able Files You can use the lt target alias gt gdb debugger with the gdbserver to debug Linux programs on the target hardware You can use any program invoked from the Linux command line with this debugger provided that the program was built to be compatible with GDB 6 1 6 Visual GDB To debug using the Microcross Visual GDB a k a Insight refer to the Microcross documentation which is offered online at www microcross com 6 2 Debugging Examples To quickly get started debugging several example files were included in the GX Linux package A list of all the examples follows 6 2 1 Example with Visua
156. the startup module is called crt0 o and the standard C libraries are libads a and libc a On embedded PowerPC systems assume that the startup module is called crt0 o and the standard C libraries are libyk a and libc a GX Linux User Guide E 97 Appendix 3 GNU X Tools PowerPC Linux Toolsuite Option Description gt gt S O environment memb On embedded PowerPC systems set the PPC_EMB bit in the a ELF flags header to indicate that eabi extended relocations are used meabi On System V 4 and embedded PowerPC systems do do not mno eaba adhere to the Embedded Applications Binary Interface eabi that is a set of modifications to the System V 4 specifications Selecting meabi means that the stack is aligned to an 8 byte boundary a function eabi is called to from main to set up the eabi environment and the msdata option can use both r2 and r13 to point to two separate small data areas Selecting mno eabi means that the stack is aligned to a 16 byte boundary do not call an initialization function from main and the msdata option will only use r13 to point to a single small data area The meabi option is on by default if you configured GCC using one of the powerpc eabi options msdata eabi On System V 4 and embedded PowerPC systems put small initialized const global and static data in the sdata2 section which is pointed to by register r2
157. tlinux usb command assuming you have GxX Linux files already loaded The pendrive should be mounted as your root filesystem if not then troubleshoot the pendrive on your host computer to see if the root filesystem looks like the same one in your rootfs directory Follow the procedures in previous sections to get NFS working to validate the root filesystem 5 6 5 Writing to On Board Flash via MMC SD Card Check to see if mmc is available in the device driver devices list cat proc devices cr If mmc Is listed on the Block devices then you may issue the following command sequence manually or add to the etc init d rcS file in rootfs and varetc to be executed automatically at startup The rcS file is like an autoexec bat file in DOS that executes commands as given at startup The microcross banner Is executed in this manner Th mmc block device will have a number associated with it when the above procedure is executed and the major number is used in making a node Example mknod var mmcblk0Opl b 254 1 cr mount t vfat var mmcblkOpl mnt mmc cr Leave the t off for ext2 and ext3 filesystems For some Cogent boards the startlinux script has the feature to mount a root filesystem that has been created on an SD or MMC card To automount this filesytem issue a startlinux mmc command in uMON Optionally you can create another startlinux script say startlinuxm
158. to decide this until the whole compilation unit has been read mcheck zero Trap do not trap on integer division by zero The default is division mcheck zero division mno check zero division mmemcpy The mmemcpy switch makes all block moves call the mno memcpy appropriate string function memcpy or bcopy instead of possibly generating inline code mlong calls Do all calls with the JALR instruction which requires loading up mno long calls a function s address into a register before the call You need to use this switch if you call outside of the current 512 megabyte segment to functions that are not through pointers mmad Permit use of the mad madu and mul instructions as on the mno mad r4650 chip mfused madd Enable disable use of the floating point multiply accumulate instructions when they are available The default is mfused madd When multiply accumulate instructions are used the intermediate product is calculated to infinite precision and is not subject to the FCSR Flush to Zero bit This may be undesirable in some circumstances nocpp Tell the MIPS assembler to not run its preprocessor over user assembler files with a s suffix when assembling them mfix sbl Work around certain SB 1 CPU core errata This flag currently works around the SB 1 revision 2 F1 and F2 floating point mflush func func Specifies the function to call to flush the and D
159. ual addresses the are used by the Linux based software All Linux kernels require that the processor support an MMU uClinux is a special version of Linux for processors that do not support an MMU The Network File System NFS allows machines to mount a disk partition on a remote machine as if it were on a local hard drive This allows for fast seamless sharing of files across a network On Screen Display Single Board Computer Software Development Kit System On a Chip The file system for a particular target hardware The hardware running Linux Trivial File System This is the small flash file system managed by the uMON bootloader Texas Instruments Inc Tools and utilities used to build applications and other code for the target hardware User Interface MicroMonitor The Lucent Technologies Inc bootloader allows users to manage the loading storing and invoking of a Linux kernel and root file system In normal operation the bootloader resides in flash and is the first program run when powering up Unless intercepted UMON will typically transfer control to the stored system Any processor compatible with the Intel 386 486 or Pentium family Execute In Place GX Linux User Guide E 103 Appendix 6 Additional Resources Appendix 6 Additional Resources ARM Ltd www arm com Atmel Corporation www atmel com BusyBox the Swiss Army Knife for Embedded Linux www busybox net Cogent Computer System
160. ucessueesseeseeeessaeessasenaass 31 3 4 2 Other Useful MicroMonitor COMMANAS cccceccccceeccceeeceeeeeeeaeececeeeeeceueeeseaeesseueessaeceseaeeeeeaeeeseeeeesaneesas 32 Section 4 0 Visual X Tools Example Application Project ccccsseseeeeeeeeeeeeeeeeeneeeeeeneees 33 Al ACO Example Progra sssaaa a E RA ER EA EATER E EE EEE E EAE EAA ESS 33 Section 5 0 Making Modifications to GX LINUX c cee ceeeceee eee eceeeeeeeeneeeneeeeeeaesenesenesenesenes 35 5 1 Modifying GX LINUX Standard Platform ccc cccccceececeeececeeececeeceeseeeeeseeeeseecesseeeeseeeeeseeeeseeeessegeesseeeseneeesaeees 35 5 1 1 Building Your Own Applications ccccccccccsecccceeceeeeceeseeeeseeeceseeeeeseeeeeseeeeeseeeeesecesseeeeseueeesseeeesseeeeseeeeas 35 5 2 Modifying GX Linux Professional Platform cccccceccceeseeeeeeeeeeeeaeeeeeeseeeeeeseeeeesseeeeeseaeeeeseaueeeseaeuseesaaeeeesseees 36 5 2 1 SX LIMUX BSP Components sisese eia aa ea A ara a eaaa E aae Ea ea ANAE a 36 5 2 2 Building All of the Components is set nsecedeemeea cast naestasnisned iamtacdaannseaadaneneiadeacalndenauannetiaeeiadamatiiedatenincdsaaneneadanays 36 5 2 3 Building All Components Excluding Examples c cccccccseeeeeeeeeeeeeseeeeeeseeeeeeseeeeeeseeseesseeseesseseeeeseeeeneas 36 5 2 4 Building Your Own AD PlICAUONS x cseeccencsenusesetssmeesnncicdeactcesaddsceebetlenanaaceniesteacenesnannedeodhudenensteadectunedencuaandeaeneds 36 5 3 Changin
161. ur files can have a significant effect on performance By changing the link order you are changing the way the executable file lies in the instruction cache The cache is a fast area of memory that stores pages of instructions so that the processor does not have to go back to slower parts of memory or even worse the disk for every new instruction Certain link orders minimize instruction cache miss The effect usually is not large but in pathological cases a really bad link order on a machine that is very sensitive to cache miss link optimization can speed up runtime by 50 percent Unfortunately not much can be said about link order optimization There are few rules if any and all the rules have many exceptions In general it is a good idea to place modules that call each other near each other on the command line The reasoning behind the heuristic is simple if function A makes many calls to function B and both A and B can fit into the cache simultaneously you will not pay a penalty for cache miss Your best chance of fitting both functions into the cache simultaneously occurs when they are located next to each other in the object file The M option which produces a load map shows you how the object file is arranged it will help you investigate cache performance Normally rearranging the order of the object modules on the command line is sufficient for experimenting with link order optimization However you can get very fine co
162. ur images to the target board After uploading three files to the target board startlinux zZimage and romfs img you can manually start GX Linux by issuing the following commands So cn get a command prompt after upload reset cr get the board in a refresh state S startlinux cr Linux boots to a user prompt On the target board in the usr bin directory are a dozen example programs that can be run from the Minicom interface Issue the following commands Gd JuSsr bin Cer ls cr You can see all examples they have a x file extension on them To run each example issue the by name command double x cr float x cr hbelileo x cr etc Step 9 Useful Linux Commands cat proc cpuinfo Show information such as bogomips architecture and manufacture information reboot Reboots system into uMON 26 E GX Linux User Guide Section 3 Getting Started 3 3 Getting Started with Application Setup on Windows Host This section explains how to build and load applications into the target Cogent development board using the Windows Cygwin host provided by Microcross on the Standard and Professional Platform CD ROMs The Application Development Platform on Windows is a complete replica of the Standard Platform on Linux host Since kernel and library building are not provided at this time on a Windows Cygwin host due to several environment issues Microcross instead chose to pre build th
163. ure 9 1 preprocessor Performed by cpp which is invoked by Gcc the preprocessor resolves directives like define include and if Preprocessing establishes the type of source code to process compiler Performed by ccc the compiler pass which produces assembly language from the input files and passes the assembly source directly to the assembler phase assembler Performed from ccc by as the GNU assembler It takes the assembly language as input and produces object files with o extensions The assembler output is relocatable object code 0 linker Performed by 1d the GNU linker Linking completes the compilation process combining all object files newly compiled and those specified as input into an executable file This step completes the final stage where the o modules are placed in their proper places in the executable file Library functions that the program refers to are also placed in the file GCC performs this task by internally invoking the linker GCC also cleans up by deleting any object files that it created from source files however it does not cleanup any pre existing object files that you specified on the command line GCC normally invokes all of these compilation steps when converting a C source program into an executable By using command line options for Gcc these steps may be invoked separately or in some combinations This provides some flexibility when building large programs or
164. used and that assembly listings al be requested also 68 m GX Linux User Guide Section 9 How to Use GNU X Tools Use the ac option to omit false conditionals from a listing Any lines which are not assembled because of a false if or ifdef or any other conditional or a true if followed by an else will be omitted from the listing Use the ad option to omit debugging directives from the listing Once you have specified one of these options you can further control listing output and its appearance using the directives list nolist psize eject title and sbttl The an option turns off all forms processing If you do not request listing output with one of the a options the listing control directives have no effect The letters after a may be combined into one option e g aln a cdhimns Turn on listings in any of a variety of ways ad _ _ Omit debugging directives _ am Include macro expansions Omit forms processing as Include symbols Set the name of the listing file You may combine these options for example use aln for assembly listing without forms processing The file option if used must be the last one By itself a defaults to ahls pd gored S O defsym sym value Define the symbol sym to be value before assembling the input file value must be an integer constant As
165. using assembly language sources or debugging 54 mw GX Linux User Guide Section 9 How to Use GNU X Tools Figure 9 1 GNU X Tools Flow Diagram c ANSI C Source cc C ANSI C Source sisi SS C Style Assembly Source goes through CPP Source Files s Assembly Source no preprocess bypass CPP GCC G Options Java Source CFLAGS LFLAGS i _ f Fortran Source 1 Er gt cpp p Ss en By ay eR ge i Fagg a ee So mcpu gt cc1 cc1plus gcj g77 C gO e S oh sS Control Program Assembly gas eti Source Files Wa gt C S E 6 Librarian ar Precompiled 0 y WI oe T Idscript gt Linker Libraries Libraries Id C lib a lib a LD Scripts _ Id elf X Alternate coff Binary ey Outputs rec Executable Formats spn 9 4 3 Control Program GCC Exactly how the GCC processes any file depends on the file s name The control program strips the initial part of the name and then determines how to process the file on the basis of the filename s extension In each case the control program passes the file to the appropriate program for preprocessing compilation or assembly and it links all resulting object modules together to produce an executable fil
166. werPC systems do do not mno regnames emit register names in the assembly language output using symbolic forms mlongcall Default to making all function calls via pointers so that mno longcall functions which reside further than 64 megabytes 67 108 864 bytes from the current location can be called This setting can be overridden by the shortcall function attribute or by pragma longcall 0 Some linkers are capable of detecting out of range calls and generating glue code on the fly On these systems long calls are unnecessary and generate slower code As of this writing the AIX linker can do this as can the GNU linker for PowerPC 64 It is planned to add this feature to 98 m GX Linux User Guide Appendix 3 GNU X Tools PowerPC Linux Toolsuite Option o the GNU linker for 32 bit PowerPC systems as well On Mach O Darwin systems this option directs the compiler emit to the glue for every direct call and the Darwin linker decides whether to use or discard it In the future we may cause GCC to ignore all longcall specifications when the linker is known to generate glue pthread Adds support for multithreading with the pthreads library This option sets flags for both the preprocessor and linker Compiler Defined Symbols From the command line in GNU X Tools Shell type gt xtools ppc linux cr pec Linux gt Cee y E cr You will get all of the compiler defined symbols printed out on the screen Press Ctr
167. x User Guide E 87 Appendix 2 GNU X Tools MIPS Linux Toolsuite Option Description preferred for some embedded systems muninit const in When used together with membedded data it will always store rodata uninitialized const variables in the read only data section Mno UninitT CcOonst in rodata msplit addresses Generate code to load the high and low parts of address constants separately This allows GCC to optimize away redundant loads of mno split the high order bits of addresses This optimization requires GNU addresses as and GNU ld This optimization is enabled by default for some embedded targets where GNU as and GNU ld are standard mexplicit relocs Use do not use assembler relocation operators when dealing with symbolic addresses The alternative selected by mno explicit mno explicit relocs is to use assembler macros instead relocs mexplicit relocs is usually the default if GCC was configured to use an assembler that supports relocation operators However there are two exceptions GCC is not yet able to generate explicit relocations for the combination of mabi 64 and mno abicalls This will be addressed in a future release The combination of mabicalls and fno unit at a time implies mno explicit relocs unless explicitly overridden This is because when generating abicalls the choice of relocation depends on whether a symbol is local or global In some rare cases GCC will not be able
168. y similar to DCW in armasm if lt logical expression gt Makes a block of code conditional End the block using endif similar to IF in armasm See also else Include a block of code if lt symbol gt is not defined End the block with endif Includes the indicated source file similar to INCLUDE in armasm or include in C sirp lt param 1 lt val 17 Repeats a block of code once for each value in the value list Mark the end of the block using a endr directive In the repeated code block use lt param gt to substitute the associated value in the value list macro lt name gt lt arg 1 ir arg arj iz arg N gt Include a block of code if lt symbol gt is defined End the block with endif Defines an assembler macro called lt name gt with N parameters The macro definition must end with endm To escape from the macro at an earlier point use exitm These directives are similar to MACRO MEND and MEXIT in armasm You must precede the dummy macro parameters by For example smacro SHIFTLEFI Ap D TE o lt 0 MOV a a ASR b exitm sendir MOV a a LSL b endm lt register name gt req This directive names a register It is similar to the RN directive in lt register_ name gt armasm except that you must supply a name rather than a number on the right e g acc req ro SECLUON lt SeECUL1On name gt Starts a new code or data section Sections in GNU are called text a ig stlags

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