Linux Cortex-M User`s Manual
Contents
1. 2 Modify the new project to automatically NFS mount a development tree from the Linux host where we have installed Linux Cortex M 3 Program the new project image into Flash so that it autoboots on the target on each power up reset 4 Develop a new custom application and a kernel module and debug them from the NFS mounted host directory without having to even reboot the target 6 2 Create a New Project This section creates a new project as a clone of the existing project and makes sure the new project builds 1 Start off of the developer project and create a clone called my_developer bash 3 28 pwd home vlad test linux cortexm 1 12 0 projects developer bash 3 2 make clone new my_developer New project created in home vlad test linux cortexm 1 12 0 projects my_developer bash 3 2 2 Goto the new project directory build it and copy the downloadable Linux image to the TFTP server directory bash 3 2 cd my_developer bash 3 2S make Image arch arm boot uImage is ready bash 3 2 cp my_developer uImage tftpboot vlad v Linux Cortex M User s Manual 16 21 Release 1 12 0 Emcraft Systems 6 3 Set Up Target for Debugging of the New Project This section sets up U Boot for debugging of the new project on the target 1 Reset the target and enter the U Boot command monitor hitting any key to stop the autoboot Hit any key to stop autoboot 0 A2F LNX EVB gt 2 Define the IP addresses for the target2. e CROSS _COMPILE arm uclinuxeabi Reference to the cross tools used to build U Boot and the Linux kernel e CROSS _COMPILE _APPS arm uclinuxeabi Reference to the cross tools used to build user space applications and tools e PATH SINSTALL_ROOT tools arm 2010q1 bin INSTALL_ROOT tools bin lt orig_path gt Path to the cross tools used by the shell e mcu lt arch gt MCU architecture supported by the Linux Cortex M distribution 4 1 5 Dependency on Host Components The Linux Cortex M distribution has the following dependencies on Linux host software components Please consult the notes below in case the Linux Cortex M development environment does not function as documented in the sections that follow e The U Boot busybox and Linux kernel build systems require that certain host packages be installed on the development host to function correctly These packages are make gcc perl and some others Please refer to 1inux Documentation Changes for a list of host tools required to build the Linux kernel The same set of tools is required for the U Boot and busybox build e The Linux Cortex M GNU debugger tools bin arm uclinuxeabi gdb and the configuration scripts require that the following dynamically linked libraries to be installed on the host o libncurses so 5 and libtinfo so 5 the ncurses libs package o libexpat so 1 the expat package e The CodeSourcery cross build tools Please refer to the to
3. MCU e bmenuconfig configure the busybox tool by running make menuconfig in the busybox source tree Copy the resultant configuration file to the project directory as project busybox e clone new newproject clone the current project into a new project with a specified name The current project directory with all sub directories is copied into the new project directory The project kernel busybox and initramfs configuration files are copied with the new name In Makefile SAMPLE is set to the name of the new project The main idea behind this framework is that each project keeps its own configuration for the Linux kernel in the project kernel MCU file its own definition of the contents of the target file system in the project initramfs file and its own configuration of busybox in the project busybox file These files are enough to rebuild both the project kernel and the project file system with a specific configuration of the busybox tool embedded from scratch If a project makes use of a custom application specific to the project such an application must be built from the sources located in an arbitrarily named sub directory local to the project directory There could be several sub directories in a project one per a custom application Each subdirectory will have its own Makefile defining rules for building the custom application from the corresponding sources Each custom application listed in CuUsTOM_APPS must have a
4. ps PID USER VSZ STAT COMMAND 2P Eo OE 324 S telnetd i RAI S 23 Start the dropbear SSH daemon to allow secure connections to the target dropbear a Connect to the target from a local host using ssh hit Enter on the password prompt psl ocean linux cortexm 1 12 0 ssh root 172 17 4 200 The authenticity of host 172 17 4 200 172 17 4 200 can t be established DSA key fingerprint is d2 d1 5f dd 84 6o ld 2free 69 0c 85 00 22 00 87 Are you sure you want to continue connecting yes no yes Warning Permanently added 172 17 4 200 DSA to the list of known hosts root 172 17 4 200 s password On the target configure a default gateway and the name resolver Note how the sample configuration below makes use of the public name server provided by Google Note also use of vi to edit target files under Linux route add default gw 172 17 0 1 vi etc resolv conf nameserver 8 8 8 8 Use wget to download a file from a remote server wget ftp ftp gnu org README Connecting Eor epr anur oro i MOSSE 0 2 Ol ale README 100 es a a ai ata ka 1765 ETA cat README This is ftp gnu org the FTP server of the the GNU project Comments suggestions problems and complaints should be reported via email to lt gnu gnu org gt Use ntpd to synchronize the time on the target with the time provided by a public server date Linux Cortex M User s Manual 5 21 Release 1 12 0 Emcraft System
5. EE EEE done Bytes transferred 1439232 15f600 hex Booting kernel from Legacy Image at 70000000 Image Name Lanux 2 6 55 erm Image Type ARM Linux Kernel Image uncompressed Data Size 439168 Bytes 1 4 MB Load Address 70008000 Entry Point 70008001 Verifying Checksum OK Loading Kernel Image OK OK Starting kernel D Linux version 2 6 33 arml vlad ocean emcraft com gcc version 4 4 1 Sourcery G Lite 2010q1 188 8 Fri Mar 25 17 26 37 MSK 2011 IP Config Complete device eth0 addr 172 17 4 150 mask 255 255 0 0 gw 255 255 255 255 host a2f 1nx evb domain nis domain none bootserver 172 17 0 1 rootserver 172 17 0 1 rootpath Freeing init memory 328K Linux Cortex M User s Manual 17 21 Release 1 12 0 Emcraft Systems init started BusyBox vl 17 0 2013 12 06 19 58 44 MSK es y joao DPA Ol PING AZ O ZO So data bytes 64 bytes from 172 17 0 1 seg 0 ttl 64 time 11 617 ms 64 bytes from 172 17 0 1 seg 1 ttl 64 time 2 016 ms 6 4 Update the New Project This section updates the new project for the required functionality and validates it on the target 1 In the new project update the target start up script so that it automatically mounts the projects directory from the Linux Cortex M installation on the development host This makes all projects immediately available on the target allowing you to edit build and test your sample applications and loadable device drivers without
6. U Boot do the following from the Linux Cortex M installation on your development host refer to Section 4 1 Go to the Linux Cortex M installation and activate it unless you have activated it already psl ocean linux cortexm 1 12 0 ACTIVATE sh psl ocean linux cortexm 1 12 0 2 Go to the top of the U Boot source tree psl ocean linux cortexm 1 12 0 cd u boot psl ocean u boot 3 Configure U Boot for your specific board Please refer to the Starter Kit Guide or BSP Guide for your hardware board for the name of the corresponding U Boot configuration target For example the following command configures U Boot for the Emcraft A2F LNX EVB board psl ocean u boot make a2f 1nx evb_config Configuring for azf 1nx evb board psl ocean u boot 4 Build the U Boot image ready for download to the target over TFTP and copy it to the TFTP server directory psl ocean u boot make psl ocean u boot cp u boot bin tftpboot psl a2f To upgrade the firmware do the following on the target 1 Configure the networking in U Boot if necessary 2 Download the U Boot image from the TFTP server A2F LNX EVB gt tftp psl a2f u boot bin Core10 100 link up 100 Full Using Corel0 100 device MAS eco aa IZ Oe wie Ie armes Gifs 112 17 ALO 2010 Filename psl a2f u boot bin Load address 0x70000000 Loading done Bytes transferred 96052 17734 hex A2F LNX EVB gt 3 Program the new U Boot image
7. file system 4 2 4 Developer Demo Project Resides in projects developer developer is intended as a template project that can be used to jump start development of custom user space applications and loadable kernel modules From the kernel configuration start up sequence perspective developer is similar to networking developer is ready for NFS mount although the user must explicitly enable the mount command in local rc and edit it for his local environment From the busybox configuration perspective developer enables insmod 1smod rmmod to allow management of loadable kernel modules developer has a custom application directory called app It contains e Loadable device driver called sample c which implements a device driver for a pseudo device that returns a certain string on attempt to read the entire device rejects any attempts to write the device e User space application called app c which opens the sample device driver using a dev sample device node file reads the device until EOF on a per byte basis and prints the read characters to the user terminal stdout Please refer to Section 6 to find our more about how developer can be used to jump start Linux Cortex M development 5 U Boot 5 1 Pointers to Detailed Information on U Boot Linux Cortex M makes use of the U Boot firmware to bring the Cortex M target up from a power on reset and to boot Linux onto the target U Boot is a popular firmware monit
8. 0 abridor ll STRING Linux viadimir emerar c com 2 6 32 26 175 fol2 1686 PAR 1 SMP Wed Aug 24 16 45 50 UTC 2011 i686 Make sure that the daemon snmptrapd is not running on your host Create the following configuration file snmptrapd conf snmpTrapdAddr udp 162 authCommunity log public and run the daemon snmptrapd on the host with the above configuration root vladimir net snmp snmptrapd C c snmptrapd conf Le f Then send a trap from the target to the host using the snmptrap application a Ghana v i e aoli IZA MYO 253 VI Bes A VIA ISS eh ISS IS ISSSTE SPSS Ering Linux Cortex M User s Manual 6 21 Release 1 12 0 Emcraft Systems On the host you should see a log message similar to the one below 2011 08 23 13245734 1982 1932 194 1955 m a UDP 1720174 201 2 244565 172 17 0 255 7 TRAP SNMP vl community public SOLA OO Enterprise Specific Trapl 99 Uptime 0 00 00 a5 SOS ills hs SERINE TS ES Ern Erase the third partition of the external Flash format it as a JFFS2 file system and then mount the newly created file system to a local directory Copy some files to the persistent JFFS2 file system storage flash_eraseall j dev mtd2 Erasing 64 Kibyte 500000 100 complete Cleanmarker written at 4f0000 mkdir m mount t jffs2 dev mtdblock2 m cp bin busybox m cp ete re 9 10 ls 1t m EWE RE X root root ooo Jam 1 DOLO re AEWRE RE lO Or root 238724 Jan 1 00 18 busybox a df File
9. 12 0 ping 172 17 4 200 PING AZ A200 2 i 4200 o6 84 bytes of data 64 bytes from 172 17 4 200 icmp_seq 1 tt1 64 time 3 11 ms 64 bytes from 172 17 4 200 icmp_seq 2 tt1 64 time 0 900 ms 64 bytes from 172 17 4 200 icmp_seq 3 tt1 64 time 0 854 ms On the target connect to a local host using telnet telnet 172 17 0 212 Entering character mode Escape character is Fedora release 12 Constantine Kernel 2 6 32 26 175 fc12 i686 on an i686 7 login psl Password Lastrloglin Mon Jan oI Seo rc con 2 ASS psl pvr logout Connection closed by foreign host Linux Cortex M User s Manual 4 21 Release 1 12 0 Emcraft Systems Start the telnet daemon to allow connections to the target telnetd Connect to the target from a local host using telnet hit Enter on the password prompt psl ocean linux cortexm 1 12 0 telnet 172 17 4 200 Weying 172 LADO Connected to 172 17 4 200 Escape character is a2f 1nx evb login root Password Note For those targets that have 8 MBytes of RAM it may be necessary to kill some of the processes that are no longer needed for subsequent steps of the demonstration sessions shown below Unless some of those processes are killed it may be not possible to run the follow up steps in the session due to insufficient run time RAM memory For instance to kill the telnetd daemon after the Telnet functionality has been tested use the following commands
10. Chip cSOC microcontrollers Linux Cortex M provides a platform and software development environment for evaluation and development of Linux on the Cortex M CPU core of the MCU devices listed above 2 Hardware Platform Depending on a specific product option Linux Cortex M comes as a software distribution image supporting the corresponding Cortex M microcontroller family For each supported microcontroller family Linux Cortex M provides support for one or more reference hardware boards Board support comes as a Board Support Package BSP specific to a particular hardware board Please refer to an appropriate Starter Kit Guide or BSP Guide for detailed information on how to install and configure Linux Cortex M on a specific hardware board This User s Manual document proceeds to outline information that is common for all supported MCU architectures and hardware boards The sample sessions provided below emphasize a concrete microcontroller however the functionality illustrated by those sessions is available on all supported architectures 3 Pre installed Demo 3 1 Pre installed Demo on Supported Hardware Platforms Those hardware boards that are shipped by Emcraft as part of a corresponding Linux Cortex M product option come with the U Boot firmware installed into the internal Flash of the microcontroller device and a Linux image installed into the external Flash memory For those product options that provide support for a third
11. Flash done Protected 2 sectors A2F LNX EVB gt 5 3 2 Autoboot The autoboot sequence in U Boot is controlled by the following environment variables e bootcmd command to execute automatically after reset To disable the autoboot undefine this variable Linux Cortex M User s Manual 13 21 Release 1 12 0 Emcraft Systems e bootdelay delay in seconds before running the autoboot command During the bootdelay countdown you can interrupt the autobooting by pressing any key 5 3 3 Networking in U Boot U Boot supports downloading of images over network using the TFTP service To enable networking the following U Boot variables must be set to values matching the local network configuration e ipaddr IP address of your A2F LNX EVB board e serverip IP address of the TFTP server e netmask local network mask optional variable e image filename of an image loaded from the TFTP server optional variable After you have defined the above variables you can use the tftp U Boot command to download images to RAM For example A2F LNX EVB gt tftp ps1 a2f networking ulmage Core10 100 link up 100 Full Using Corel0 100 device UTS sera Seiya IAP 0 Lp vs US arias abel 12 17 Lo AO Filename ps1 a2f networking ulmage Load address 0x70000000 Loading ARRE RRA E E E H done Bytes transferred 821888 c8a80 hex A2F LNX EVB gt 5 3 4 Flash related Commands To program a Linux image to the Flash use the upda
12. Linux Cortex M User s Manual Release 1 12 0 Emcraft Systems Table of Contents 1 OVERVIEW iinne areenaa inaa aa aa naaa iii AAA AAA AAA A dic ad 3 2 HARDWAREPLATFOR Music 3 3 PRE INSTALLED DEMO ici iia 3 3 1 PRE INSTALLED DEMO ON SUPPORTED HARDWARE PLATFORMS 3 2 DESCRIPTION OF THE PRE INSTALLED DEMO 2 eccceeeeeeeeeeaeeeeeeeceeeeaeeeeeeeeesenaeaeeeeeeeseceneaeeeeeeeeneeeea 4 LINUX CORTEX M SOFTWARE DEVELOPMENT ENVIRONMENT ccsccccessscceseseeeeeeseeeeeeees 7 4 1 DISTRIBUTION AND INSTALLATION 4 1 1 Distribution Image 4 1 2 Installation Tree 4 1 3 GNU Eross Build Tools E E A aa cea ad dee eee ee aa 4 1 4 Activation e delata ist 4 1 5 Dependency on Host Components 4 2 PROJECTS FRAMEWORK ccccceseeeeeeeeeeeeees 4 2 1 Multiple Target Projects 00 08 4 2 2 Hello World Demo Project 4 2 3 Networking Demo Project 4 2 4 Developer Demo Project latii a atte ees ed tated et ate iad ace edd 5 1 POINTERS TO DETAILED INFORMATION ON U BOOT ccceseececeeeceeeessecececeseceeaseeeeeeseaueaeeeeeeenseauensness 12 5 2 U BooT THEORY OF OPERATION 5 3 SELECTED USE SCENARIOS vevicccscccccicaccuscucestacscseveeucderccvcstvasvascucesdacuabevcouedvadcncevdeevaccncoscosuesveceuctvadsusch 5 3 1 U BO0 ENVIO Meta aia 5 3 2 AUtODOOt ccccccccccccccnccccccoccnnnns 5 3 3 Networking in U Boot 5 3 4 Flash related Commands 5 3 5 U B
13. Makefile in the custom application sub directory defining the following targets e ali build the application from the sources e clean clean anything that has been previously built Content of the initramfs file system is defined for a project in the file named project initramfs Note that this file makes use of INSTALL_ROOT to provide a reference to the top of the Linux Cortex M installation directory 4 2 2 Hello World Demo Project Resides in projects hello A single application Linux configuration demonstrating the minimal possible kernel initramfs memory requirements The application starts as an init process as soon as the kernel has mounted the root filesystem mounts the proc filesystem and prints out the content of proc meminfo Then it proceeds to print a Hello message in an endless loop There is no way to interrupt or stop the application rather than resetting the system 4 2 3 Networking Demo Project Resides in projects networking Linux Cortex M User s Manual 11 21 Release 1 12 0 Emcraft Systems Implements the functionality of the demo system that comes pre installed on the A2F LNX EVB board Please refer to Section 3 for a detailed description of the demo The demo includes the dropbear SSH server configured to accept only DSA connections To configure the server to accept RSA connections edit networking initramfs and rebuild the demo to add the etc dropbear dropbear_rsa_host_key file to the target
14. able kernel module 5 Unload the device driver mnt my_developer app rmmod sample 6 Iterate to update and test your custom application from the NFS mounted host directory 7 Support and Further Materials Visit Emcraft s web site at www emcraft com to obtain additional materials related to Linux Cortex M Linux Cortex M User s Manual 21 21 Release 1 12 0
15. and a TFTP server define the name of the image to be downloaded by tftpboot A2F LNX EVB gt setenv ipaddr 172 17 4 150 A2F LNX EVB gt setenv serverip 172 17 0 1 A2F LNX EVB gt setenv image vlad v 3 Check that U Boot defines appropriate commands macros for booting the Linux image from a TFTP server and running it on the target A2F LNX EVB gt printenv netboot netboot tftp fimage run addip bootm A2F LNX EVB gt printenv addip addip setenv bootargs S bootargs ip S ipaddr serverip S gatewayip netmask hostname eth0O off 4 Save the updated environment in Flash A2F LNX EVB gt saveenv Saving Environment to Flash Un Protected 2 sectors Erasing Flash done Erased 2 sectors Writing Lo Flash done Protected 2 sectors A2F LNX EVB gt 5 Boot the Linux image over the network and test that the networking is functional Note that given a correct ipaddr setting in U Boot the kernel brings up the Ethernet interface in Linux automatically without an explicit ifconfig command A2F LNX EVB gt run netboot Core10 100 link up 100 Full Using Corel0 100 device MAS Teo Seuagee M2 oI oOo ile wie ie evelcligersic 18 1 2 IG 4A 0 Filename vlad v Load address 0x70000000 Loading 4A tE H AE HAE EAE TE H AE HE FE TE FE AE HE FE E FE TE FE AE HE FE AE FE TE HE AE E FE TE FE TE HE AE E FE TE FE AE AE TE E FE TE E AE E E E E E E E EE EE EEE FEFE AE AE FE AE FE TE AE AE E FE TE FE AE AE TE E E E E E E E EE E EE
16. e e ACTIVATE sh shell script you need to perform in order to activate the Linux Cortex M development environment on your host 4 1 3 GNU Cross Build Tools As a next step in the Linux Cortex M installation procedure you need to download the GNU cross build tools for the Cortex M target The tools are available from CodeSourcery and can be downloaded from the following URL http www codesourcery com sgpp lite arm portal package6503 public arm uclinuxeabi arm 2010q1 189 arm uclinuxeabi i686 pc linux gnu tar bz2 It is recommended that you install the GNU development tools to the tools directory of the Linux Cortex M installation as follows psl pvr linux cortex m 1 12 0 cd tools psl pvr tools wget http www codesourcery com sgpp lite arm portal package6503 public arm uclinuxeabi arm 201091 89 arm uclinu uxeabi 1686 pe linux gnu tar B22 Saving to arm 2010q1 189 arm uclinuxeabi i686 pce linux gnu tar pz2 psl pvr tools tar xvfj arm 2010q1 189 arm uclinuxeabi 1686 pc linux gnu tar bz2 arm 2010q1 arm uclinuxeabi arm 2010q1 arm uclinuxeabi libc It is possible to install the tools to an alternative location however should you do that you will need to modify the ACTIVATE sh script to provide a correct path to the installed tools Linux Cortex M User s Manual 8 21 Release 1 12 0 Emcraft Systems specifically PATH must include a correct path to the directory where you have installed the c
17. eady provides a loadable kernel device driver implemented in sample c The device driver allows reading device data from a pseudo device which keeps its data in a character array defined in sample c Let s enhance the device driver to allow changing the device data by writing into the character array Note that this being a simple example of a development session the code below assumes that the user supplied device data does not exceed 1023 bytes bash 3 2 vi sample c pe Device data y static char sample_str 1024 This is the simplest loadable kernel module n je Device write if static ssize t sample write struct file ilp const char butfer size_t length loff_t offset int ret 0 Check that the user has supplied a valid buffer e af 1 access ok 0 butter lengtal ret EINVAL goto Done Linux Cortex M User s Manual 19 21 Release 1 12 0 Emcraft Systems Write the user supplied string into the sample device string S strncpy sample_str buffer length sample_str length 0 offset length 1 ret length Done d_printk 3 length d n length return ret 3 Build the updated device driver bash 3 2 make 4 On the target go to the application directory mnt my_developer app cd mnt my_developer app 5 Install the updated device driver mnt my_developer app insmod sample ko 6 Test that the read operation returns the content of the bu
18. ernel command string that U Boot passes to the Linux kernel as the parameters 5 3 Selected Use Scenarios 5 3 1 U Boot Environment To manipulate the U Boot environment the following commands are used e printenv lt var gt print the value of the variable var Without arguments print all environment variables A2F LNX EVB gt printenv bootargs console ttyS0 115200 panic 10 bootcmd run flashboot bootdelay 3 baudrate 115200 hostname a2f 1nx evb loadaddr 70000000 addip setenv bootargs bootargs ip S ipaddr S serverip S gatewayip netmask S hostname eth0O off flashaddr 74020000 flashboot run addip bootm flashaddr netboot tftp fimage run addip bootm image a2f uImage ethact Core10 100 stdin serial stdout serial stderr serial ethaddr 00 22 44 66 88 AA Environment size 430 4092 bytes A2F LNX EVB gt Note that the TTY device number ttyS0 and other default options may differ on various boards e setenv lt var gt lt val gt set the variable var to the value val A2F LNX EVB gt setenv image psl a2f hello image A2F LNX EVB gt printenv image image ps1 a2f hello image A2F LNX EVB gt Running setenv lt var gt will un set the U Boot variable e saveenv save the up to date U Boot environment possibly updated using setenv commands into persistent storage A2F LNX EVB gt saveenv Saving Environment to Flash Un Protected 2 sectors Erasing Flesh done Erased 2 sectors Writing to
19. having to re Flash or even reboot the target bash 3 2 vi local rc bin sh mount t proc proc proc mount t sysfs sysfs sys mount t devpts none dev pts mkdir mnt mount o nolock rsize 1024 172 17 0 1 home vlad test linux cortexm 1 12 0 projects mnt ifconfig lo 127 0 0 1 2 Build the updated project and copy it to the TFTP server directory bash 3 2S make cp my_developer uImage tftpboot vlad v 3 Reboot the target load the updated image over the network and test it reboot f Restarting system Hit any key to stop autoboot 0 A2F LNX EVB gt run netboot tt started Bus y Box ZO l 016 so 518 74 AMS mount rootfs on type rootfs rw proc on proc type proc rw relatime sysfs on sys type sysfs rw relatime none on dev pts type devpts rw relatime mode 600 ptmxmode 000 172 17 0 1 home vlad test linux cortexm 1 12 0 projects on mnt type nfs rw relatime vers 3 rsize 1024 wsize 32768 namlen 255 hard nolock proto udp port 65535 t imeo 7 retrans 3 sec sys mountport 65535 mountproto addr 172 17 0 1 ls lt mnt drwxr xr x 4 19270 T9270 4096 Mar 25 2011 my_developer drwxr xr x 4 19270 19270 4096 Mar 25 2011 developer EW e SS 1270 19270 3581 Mar 25 2011 Rules make drwxr xr x SS Ane LDL TO 4096 Mar 25 2011 hello drwxr xr x SS 210 19270 4096 Mar 25 2011 networking me 6 5 Install the New Project to Flash This section installs the new project to Flash so that it automatica
20. ilt in device data mnt my_developer app cat dev sample This is the simplest loadable kernel module 7 Write into dev sample in order to change the device data and test the device returns the updated data on a next read mnt my_developer app cat gt dev sample This is the new content of dev sample D mnt my_developer app cat dev sample This is the new content of dev sample 8 Unload the device driver mnt my_developer app rmmod sample 9 Iterate to update and test your custom device driver from the NFS mounted host directory 6 7 Develop a Custom User Space Application over NFS 1 You are in the application sub directory in your project s directory bash 3 2 pwd home vlad test linux cortexm 1 12 0 projects my_developer app 2 The developer project you have cloned your new project off already provides a user space application implemented in app c This is an example so let s add a simple print out to the application code bash 3 28 vi app c printf s THIS IS CONTENT OF s n app name dev name Read the sample device byte by byte E while 1 Linux Cortex M User s Manual 20 21 Release 1 12 0 Emcraft Systems 3 Build the updated application bash 3 2 make 4 On the target install the device driver and test the updated application mnt my_developer app insmod sample ko mnt my_developer app app app THIS IS CONTENT OF dev sample This is the simplest load
21. ld application networking a basic shell and networking demonstration and developer a template project demonstrating development of a custom Linux Cortex M application You will be able to add more projects to this directory and develop your own embedded applications using this framework Each project directory such as projects hello contains the following configuration files e project kernel MCU Kernel configuration for this project Note that the kernel configuration is specific for the microcontroller architecture supported by the distribution e project busybox busybox configuration for this project e project initramfs File defining content of the initramfs filesystem for this project When you run make linux or simply make from the project directory the build system builds project specific versions of the Linux kernel and busybox then creates an initramfs filesystem containing the newly built busybox binary as well as other target files defined by the initramfs filesystem specification file and finally wraps it all up into a Linux image ready for download to the target by U Boot Each project directory has a Makefile identifying the following make variables You need to set these variables correctly for your project e SAMPLE the name of the project The downloadable Linux image has this name with the uImage extension Additionally SAMPLE is passed to the initramfs build subsystem as a reference to the direct
22. lly boots up on the target on any power up reset 1 At the U Boot prompt load the Linux image into the target RAM over TFTP and program it to Flash A2F LNX EVB gt print image image vlad v Linux Cortex M User s Manual 18 21 Release 1 12 0 Emcraft Systems A2F LNX EVB gt run update Core10 100 link up 100 Full Using Corel0 100 device TMUP irom server 12 Oni our LPaddresis us 2 AS O Filename vlad v Load address 0x70000000 Loading AH H AE HAE E AE TE H AE HE FE TE FE AE HE FE E FE TE HE FE HE FE E FE TE HE FE HE FE TE FE AE HE FE E FE TE FE AE HE FE E FE TE HE AE AE FE E E E E E E E E EEE FEFE AE HE FE E FE TE HE FE E FE TE FE AE HE FE E FE TE E E E E E E E E E EE EEE done Bytes transferred 1439232 15f600 hex Un Protect Flash Bank 1 Erased 22 sectors COPI CONEISHIE RONE A2F LNX EVB gt 2 Reset the board and make sure that the new project boots from Flash in the autoboot mode A2F LNX EVB gt reset resetting Hit any key to stop autoboot 0 Booting kernel from Legacy Image at 74020000 nas ta rted Busy Boo EOS LSO o 4 AMS ls lt mnt drwxr xr x 4 19270 19270 4096 Mar 25 2011 my developer o a 6 6 Develop a Custom Loadable Device Driver over NFS 1 Go to the application sub directory in your project s directory bash 3 2 cd app bash 3 2S pwd home vlad test linux cortexm 1 12 0 projects my_developer app 2 The developer project you have cloned your new project off alr
23. me Image Type ARM Linux Kernel Image uncompressed Data Size 821816 Bytes 802 6 kB Load Address 70008000 Entry Point 70008001 Verifying Checksum OK Loading Kernel Image OK OK Starting kernel Uncompressing Linux done booting the kernel igsLinux version 2 6 33 arml psl ocean emcraft com gcc version 4 4 1 Sourcery Gtt Lite 2010q1 168 1 Fri Dec 06 19 59 56 MSK 2013 CPU ARMv7 M Processor 411fc231 revision 1 ARMv7M CPU NO data cache NO instruction cache Machine Actel A2F Freeing init memory 292K init started BusyBox vl 17 0 2013 12 06 19 58 44 MSK The Linux kernel is configured to mount a root filesystem in the external RAM using the initramfs file system initramfs is populated with required files and utilities at the kernel build time and then simply linked into the Linux image initramfs doesn t have hard limits on its size and is able to grow using the otherwise unused RAM memory The Linux image installed on the board provides a demonstration of basic shell and network capabilities of Linux Cortex M In addition to that the demo provides support for Flash partitioning and persistent data storage using the JFFS2 journalled file system for the external Flash memory Here is how you can test some of these capabilities From a local host test that the target is accessible over network assuming that the board is assigned with the 172 17 4 200 IP address psl ocean linux cortexm 1
24. olchain README at http www codesourcery com s lite arm portal doc7632 qgetting started pdf Linux Cortex M User s Manual 9 21 Release 1 12 0 Emcraft Systems e The tools mkimage utility It is expected that the utility will work as is on most of today s Linux distributions If it fails to run on a certain host you can build it for your specific Linux host from the sources included in the Linux Cortex M distribution by running make tools from the top of the U Boot tree e To exercise the sample projects included to the Linux Cortex M distribution you need to install the following host packages o NFS server o TFTP server o Terminal emulator picocom minicom kermit or PuTTY If your target board uses USB for the serial console connection you might need to install the FTDI USB UART driver from http www ftdichip com Drivers VCP htm for your host 4 2 Projects Framework 4 2 1 Multiple Target Projects In the Linux Cortex M installation there is a directory called projects which provides a framework that you will be able to use to develop multiple projects embedded applications from a single installation of Linux Cortex M This directory has the following structure e projects Rules make build rules common for all projects e projecti Projecti source files and build tree e project2 Project2 source files and build tree Oo The installation provides three sample projects called hello A Hello wor
25. oot Self Upgrade ico ade 6 SAMPLE DEVELOPMENT SESSION nsnnnnnnnnnnnnnnnnnnnnennnrnnnrnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennne ennenen nenna 6 1 SAMPLE SESSION OUTLINE wcccccvicccccisasseccvecttecdvaveasecceudovussivedsacduocvestasuacocdeudecvecicetvacdascisecdadusterseveevaccs 620 CREATE ANEWPROJECT aaron 6 3 SETUP TARGET FOR DEBUGGING OF THE New PROJECT 6 4 UPDATE THE NEW PROJECT ccccseseecececeeceaeenssceceeeceaeeasececeeeseaueaeeeeeeeseaueaseeeeseeseauenseeeeseeseaneseseneees 6 5 INSTALL THE NEW PROJECT TO FLASH sssssecccececeesescececeeeceanseeeceeeeeseeaseeseeceeeseeaaeeeeeseeaneaeneeeeeseeas 6 6 DEVELOP A CUSTOM LOADABLE DEVICE DRIVER OVER NFS 6 7 DEVELOP A CUSTOM USER SPACE APPLICATION OVER NFS 7 SUPPORT AND FURTHER MATERIALS 0 c cccccccsceeeeeseceeeseeesceeseeeeeseaeseseeeseaeseseeeseaeseseeesseseenans 21 Linux Cortex M User s Manual 2 21 Release 1 12 0 Emcraft Systems 1 Overview This document is a User s Manual for Linux Cortex M covering the following products e Linux STM32 supporting the STmicroelectronics Cortex M3 based STM32F2 and Cortex M4 based STM32F4 microcontrollers e Linux LPC supporting the NXP Cortex M3 based LPC178X LPX18XX and LPC43XX microcontrollers e Linux Kinetis supporting the Freescale Cortex M4 based Kinetis K70 microcontrollers e Linux SmartFusion supporting the Microsemi Cortex M3 based SmartFusion and SmartFusion2 configurable System On
26. or developed and maintained by DENX Software Engineering www denx de DENX publishes extensive U Boot user documentation at their web site This section provides a brief introduction to U Boot as relevant to the Linux Cortex M software environment 5 2 U Boot Theory of Operation A typical Linux Cortex M boot up sequence is as follows e U Boot firmware runs on the target from the integrated Flash eNVM eSRAM no external memory required and performs all required initialization from power on reset including setting up the memory controller for external memory accesses e U Boot relocates Linux image from external Flash to external RAM and passes control to the kernel entry point in RAM External Flash resides at the memory interface Linux image can be compressed to save the Flash storage in this case U Boot uncompresses the image when relocating it to RAM e Linux proceeds to boot up and mount a RAM based filesystem initramfs as a root filesystem initramfs is populated with required files and directories at build time and is then simply linked into the kernel Linux Cortex M User s Manual 12 21 Release 1 12 0 Emcraft Systems U Boot operation is controlled at run time by the so called environment variables which are stored in persistent storage such as external Flash Each environment variable controls a certain aspect of U Boot operation For instance there is an environment variable called bootargs that defines a k
27. ory where filesystem binaries reside e CUSTOM_APPS this variable provides a list of the sub directories containing custom applications for the project Custom applications are built in the specified order prior to building the Linux kernel and initramfs images If a project doesn t have custom applications the variable should be left empty The following make targets are implemented in projects Rules make common build rules file Linux Cortex M User s Manual 10 21 Release 1 12 0 Emcraft Systems e all or linux build an uncompressed Linux image ready for download to the target and place it to the project directory as lt project gt ulImage e kclean clean up the Linux kernel source tree by running make clean in INSTALL_ROOT linux e bclean clean up the busybox source tree by running make clean in INSTALL_ROOT A2F busybox e aclean clean up the custom application source trees by running make clean in each application source directory as listed in CUSTOM_APPS e clean clean up the entire project by removing lt project gt uImage and then cleaning up the Linux kernel and busybox trees as described above Additionally if CUSTOM_APPS is not empty make clean is performed in each custom application sub directory e kmenuconfig configure the Linux kernel by running make menuconfig in the Linux source tree Copy the resultant configuration file to the project directory as project kernel
28. party hardware board you will have to install U Boot and Linux onto your board as explained in a corresponding Starter Kit Guide or BSP Guide 3 2 Description of the Pre installed Demo The installed Linux image provides a demonstration of the basic shell networking and file system capabilities supported by Linux Cortex M The specific functionality available in that demo is described in detail below On a power on or reset U Boot runs from the embedded Flash and uses the embedded SRAM of the microcontroller as a storage for volatile data Having completed the basic initialization U Boot configures the memory controller to allow accesses to the external RAM and Flash memory and then copies the Linux image from Flash to RAM and jumps to the Linux kernel entry point in RAM It is possible to interrupt the U Boot autoboot sequence by hitting a key before U Boot starts relocating the Linux image to RAM and enter the command line interface of U Boot however assuming no operator intervention U Boot proceeds to boot Linux up as soon as possible Linux Cortex M User s Manual 3 21 Release 1 12 0 Emcraft Systems U Bootm 2010 08 linux rtexa 10 Deer 06 2013 SiS A5 CPU SmartFusion FPGA Cortex M3 Hard IP Board A2F LNX EVB Rev 2 A www emcraft com DRAM 16 MB Flash 8 MB In serial QUE serial Mice serial Net Core10 100 Hit any key to stop autoboot 0 Booting kernel from Legacy Image at 74020000 Image Name RUSS gt o
29. ross tools The tools can be installed from an unprivileged account In case you already have the toolchain installed on your development host it would be the case for instance if you have more than one installation of Linux Cortex M on your host and the underlying filesystem supports symbolic links DOS FAT does not you do not have to install the whole toolchain again Instead do the following psl pvr linux cortexm 1 12 0 cd tools psl pvr tools ln s lt path to tools gt arm 2010q1 Note The CodeSourcery tools are 32 bit applications and need a compatibility library to run on 64 bit Linux OS distributions On the recent Fedora distributions the compatibility package e g glibc 2 17 14 fc19 i686 is installed by default On Debian you need to install it running sudo apt get install ia32 libs 4 1 4 Activation Whenever you want to activate a Linux Cortex M development session go to the top of your Linux Cortex M installation and run psl pvr linux cortexm 1 12 0 ACTIVATE sh Note the space after the dot This command has the same effect as source ACTIVATE sh This command sets up exports the following environment variables required by the Linux Cortex M development environment e INSTALL_ROOT lt dir gt root directory of the installation This variable is used by the Linux Cortex M make system as well as in the project initramfs file to provide a reference to the Linux Cortex M installation directory
30. s Mn usa AL OOHOS 0S WAS SO ntpd p 0 fedora pool ntp org sleep 5 date ML DEG ONS ALP SONGS SvA ne 2043 Mount a directory exported by a development host over NFS mount o nolock rsize 1024 172 17 0 212 opt tmp mnt mount rootfs on type rootfs rw proc on proc type proc rw relatime none on dev pts type devpts rw relatime mode 600 ptmxmode 000 IA OZ optaron matt yenes rw relatime vers 3 rsize 1024 wsize 32768 namlen 255 hard nolock proto udp port 65535 t imeo 7 retrans 3 sec sys mountport 65535 mountproto addr 172 17 0 212 1s mnt CREDITS busybox hello c hello2 gdb tests tgz address_cache demo hello gdb runtests sh ulmage bacserv event hello good test window bin hello hello2 test log Start the HTTP daemon httpd h httpd html y From a local host open a Web browser to http 172 17 4 200 and watch the demo web page provided by the Cortex M target Next step is to test SNMP Make sure that the daemon snmpd is not running on your host Create the following configuration file snmpd conf agentAddress udp 161 rocommunity public default rwcommunity private default and run the daemon snmpd on the host with the above configuration root vladimir net snmp snmpd C c snmpd conf Le f Then run the snmpget application on the target and collect information about the host using the snmpget application eenmpger c public 172 17 0 253 1 3 0 1 2 1 1 1
31. system 1K blocks Used Available Use Mounted on dev mtdblock2 5120 436 4684 9 m m busybox echo Hello from Flash Hello from Flash z umount m Reboot the target reboot f Restarting system U Boot 20108038 Ra 2A levo IO Dec 06 20135 gt TSAA 4 Linux Cortex M Software Development Environment 4 1 Distribution and Installation 4 1 1 Distribution Image The Linux Cortex M development software is distributed as a 1inux lt mcu gt lt release gt zip file available for download from the Emcraft site When unpacked this archive contains along with the other materials the software distribution file 1inux lt MCU gt lt release gt tar bz2 That file can be installed to an arbitrary directory on your Linux development host as follows psl ocean SF mkdir release psl ocean SF cd release psl ocean release tar xvjf linux A2F 1 12 0 tar bz2 linux cortexm 1 12 0 linux cortexm 1 12 0 linux linux cortexm 1 12 0 linux lib psl ocean SF ls 1 linux cortexm 1 12 0 total 24 drwxr xr x 3 psl users 4096 2013 12 06 17 06 AZF rwxr xr x 1 psl users 315 2013 12 06 16 26 ACTIVATE 6h drwxr xr x 24 psl users 4096 2013 12 06 21 32 linux drwxr xr x 5 psi users 4096 2013 12 06 20 16 projects drwxr xr x 3 psl users 4096 2013 12 06 19 14 tools Orwxr xr x 31 psl users 4096 0123 12 06 19 16 u boot You do not need to be the superuser root in order to install the Linux Cortex M distribution The ins
32. tallation can be performed from an arbitrary unprivileged user account Linux Cortex M User s Manual 7 21 Release 1 12 0 Emcraft Systems 4 1 2 Installation Tree Having been installed onto the Linux host the Linux Cortex M provides the following files and directories relative to the top of the installation directory e A2F this is a directory with target components e A2F busybox busybox source and development tree e A2F dropbear dropbear SSH server source and development tree e A2F net snmp source and development tree of the net snmp package e A2F uclibc source and development tree of the uClibc package e A2F gdb 2011 03 source and development tree of the GNU Debugger package e A2F hostapd 1 0 source and development tree of the HostAP Daemon package e A2F wireless tools source and development tree of the Wireless Tools package e A2F libn1 3 2 11 source and development tree of the Netlink Protocol Library package e A2F netperf 2 6 0 source and development tree of the Netperf network benchmarking package e A2F root pre built target binaries ready for use on the target e u boot U Boot source and development tree e linux Linux uClinux kernel source and development tree e projects sample projects embedded applications e tools development tools e tools bin mkimage utility used by the Linux Cortex M kernel build process to create a bootable U Boot kernel image such as uImag
33. te U Boot macro as follows A2F LNX EVB gt print update update tftp image prot off flashaddr filesize era flashaddr filesize cp b loadaddr flashaddr filesize A2F LNX EVB gt setenv image psl a2f networking uImage A2F LNX EVB gt run update Alternatively you can program a Linux image to the Flash using the following sequence of commands the commands are only valid for the NOR type of the Flash e Download the image to RAM A2F LNX EVB gt tftp ps1 a2f networking ulmage Core10 100 link up 100 Full Using Corel0 100 device UDINE on Saa U2 oI Oe willie Ie arre ts 12 OA Filename psl a2f networking uImage Load address 0x70000000 Loading HFHEEEEEEEEEEEEREEREEE EER TE FE AE HE AE E FE TE HE AHH E H done Bytes transferred 821888 c8a80 hex A2F LNX EVB gt e Unprotect Flash A2F LNX EVB gt protect off all Un Protect Flash Bank 1 A2F LNX EVB gt e Erase the destination Flash area A2F LNX EVB gt erase S flashaddr filesize Linux Cortex M User s Manual 14 21 Release 1 12 0 Emcraft Systems a done Erased 13 sectors A2F LNX EVB gt e Copy the image from RAM to Flash A2F LNX EVB gt cp b loadaddr flashaddr filesize Copy to Flash done A2F LNX EVB gt 5 3 5 U Boot Self Upgrade The Linux Cortex M distribution provides a full tree of the U Boot source files This allows you to configure or otherwise enhance U Boot for your specific needs To build
34. to the embedded Flash of the MCU using the cptf command Note that the cpt f command automatically resets the target upon completion of the eVNM upgrade which calls the newly programmed image from the reset vector in the eNVM Note also that the first parameter passed to the cpt f command specifies the base address of the embedded Flash area being updated by the command Depending on your CPU pass the following address as the first parameter to cptf o STM32F 0x08000000 Linux Cortex M User s Manual 15 21 Release 1 12 0 Emcraft Systems o LPC17xx 0x0 o SmartFusion and SmartFusion2 0x0 o Kinetis 0x0 As an example the following command performs the U boot self upgrade on SmartFusion A2F LNX EVB gt cptf 0x0 S loadaddr filesize 1 cptf Updating eNVM Please wait U Bootes OURO San DS RO OZ SEL o 2 CPU SmartFusion FPGA Cortex M3 Hard IP Board A2F LNX EVB Rev 2 A www emcraft com A2F LNX EVB gt Note Be extra careful when performing the cptf command specified above In case you program an incorrect U Boot image to the eNVM this will render the board non bootable The only resort in this scenario is to program the U boot image to the board over the JTAG port 6 Sample Development Session 6 1 Sample Session Outline This sample session illustrates a possible software development cycle in Linux Cortex M We will do the following 1 Create a new project by cloning it off of the developer demo project
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