OpenBricks Embedded Linux Framework
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1. can be yes or no defaults to no In addition a flag can declare additional depends which will be carried by the package if the flag is enabled e PKG_DEPENDS_ flag PKG_BUILD_DEPENDS_ flag PKG_RUN_DEPENDS_ flag A package can also force specific flags to be enabled by declaring them in PKG_REQUIRES_USE If the package requires a specific use flag to be enabled only for a given package use the syntax package flag in PKG_REQUIRES_USE In this case the package must also be listed in the PKG_DEPENDS For example PKG_REQUIRES_USE qt mysql xorg forces the xorg flag to be globally enabled and the mysql flag to be enabled for the qt package 7 2 2 Repository Download PKG_URL can point to the location of a source code repository In this case PKG_URL_PROTO specifies the repository type e git for a git repository e hg for a Mercurial repository e svn for a Subversion repository Note that PKG_URL can contain any URL permissible by the respective source code management tool such as git svn or http PKG_URL_REV can optionally specify the revision branch tag of the source code to download If omitted the default source code version is obtained It is recommended to specify a particular revision and to include PKG_URL_REV in PKG_VERSION such as shown in the example below Note that PKG_VERSION should start with a number or the letter r so that build directories can be automatically deleted When using PKG_U2. 7 a Packas scmpts gt o cre ssc 7 3 1 need_unpack script 7 3 2 unpack script 7 3 3 build script 7 3 4 installscript 7 3 5 installdev script 7 3 6 Helper functions A Understanding Kconfig File Format A l Introduction A 2 Menu entries A 3 Menu attributes A 4 Menu dependencies A 5 Menu structure A 6 Kconfig syntax A 7 Kconfig hints A 7 1 Adding common features and make the usage configurable ooo e a A 7 2 Build as module only B Adding a new package 11 11 12 12 12 13 13 14 15 15 15 16 16 17 19 20 21 21 23 23 23 23 24 24 24 26 26 26 27 28 29 29 31 31 31 32 OpenBricks Embedded Linux Framework User Manual C Adding a new architecture D Adding a new platform E Adding a new machine F Adding a new distribution flavour 33 34 35 36 OpenBricks Embedded Linux Framework User Manual 1 36 Chapter 1 OpenBricks Introduction 1 1 What is it OpenBricks is an enterprise grade embedded Linux framework that provides easy creation of custom distributions for industrial embedded devices It features a complete embedded development kit for rapid deployment on x86 ARM PowerPC and MIPS systems with support for industry leaders Pick your device select your software bricks and cook your product 1 2 Who is it for Individuals and companies t
3. Flavours are defined in config flavours where every flavour has a subdirectory Most settings are defined in the meta file e FLAVOUR_NAME the name of the flavour must coincide with the flavour directory name e FLAVOUR_DISTRONAME the user visible flavour name e FLAVOUR_DEPENDS the packages the flavour requires to be installed can be all to require all packages defaults to no package e FLAVOUR_USE the features i e use flags the flavours requires to be enabled by default can be all to require all features defaults to no feature e FLAVOUR_SHORTDESC used as the short description for the flavour should be one line summary e FLAVOUR_LONGDESC used as the long description for the flavour In addition a flavour can define arch specific depends using FLAVOUR_DEPENDS_farch e g FLAVOUR_DEPENDS_arm A flavour can override the default BusyBox configuration with a busybox conf file in its directory OpenBricks Embedded Linux Framework User Manual 13 36 6 3 2 Architectures Platforms are defined in config platforms where every architecture has a subdirectory The arch settings are defined in a meta file e ARCH_NAME the name of the architecture must coincide with the arch directory name e ARCH_DESC the user visible name of the architecture will be displayed in the Kconfig menu defaults to ARCH _NAME e ARCH_HELP the user
4. PKG_DEPENDS_uclibc libiconv PKG_DEPENDS_vaapi libva PKG_DEPENDS_vdpau libvdpau PKG_DEPENDS_sd1 SDL PKG_DEPENDS_xorg 1ibX11 libXv libXxf86vm PKG_RUN_DEPENDS_unrar unrar PKG_BUILD_DEPENDS_live live PKG_DEPENDS_dvd l1ibdvdread libdvdnav PKG_DEPENDS_bluray libbluray PKG_PRIORITY standard PKG_SECTION multimedia PKG_SHORTDESC movie player for Unix like systems PKG_LONGDESC MPlayer plays most MPEG VOB AVI Ogg OGM VIVO ASF WMA WMV QT MOV MP4 lt lt FLI RM NuppelVideo yuv4mpeg FILM RoQ PVA files supported by many native XAnim gt OpenBricks Embedded Linux Framework User Manual 23 36 RealPlayer and Win32 DLL codecs It can also play VideoCD SVCD DVD 3ivx RealMedia and DivX movies Another big feature of MPlayer is the wide range of supported output gt drivers It works with X11 Xv DGA OpenGL SVGAlib fbdev DirectFB but also SDL plus all its drivers and some low level card specific drivers for Matrox 3Dfx and gt Radeon Mach64 and Permedia3 Most of them support software or hardware scaling therefore allowing fullscreen display MPlayer is also able to use some hardware MPEG gt decoder boards such as the DVB and DXR3 Hollywood 7 3 Package scripts All the scripts in the package directory follow some conventions e the script should be written for the Bourne shell bin sh bashisms should be avoided checking the scripts with a modern
5. TechNexion TAO 3530 Thunder Board x touchbook Always Innovating Touch Book zoom2 TI OmapZoom 2 omap4 All TI OMAP4 equipped boards pandaboard PandaBoard s3c24xx All Samsung S3X24xx equipped boards gta01 OpenMoko Neo 1973 gta02 OpenMoko Neo FreeRunner tegra2 All nVidia Tegra250 equipped boards x harmony nVidia Harmony evaluation board versatilepb ARM Versatile Platform Baseboard ARM9 reference platform qemu versatilepb machine as simulated by QEMU ux500 ST Ericsson U8500 U5500 smartphone platform snowball v3 ST Ericsson Snowball V3 rev x snowball v5 ST Ericsson Snowball V5 rev or later 1386 generic 32 bits x86 1586 PCs x vmware 32bits x86 VMware optimized virtual machine mips generic 32bits MIPS powerpc generic 32bits PowerPC G3 Macintosh powerpc64 6 36 OpenBricks Embedded Linux Framework User Manual 7 36 generic 64bits PowerPC G5 Macintosh e x86_64 generic 64bits x86 AMD64 Intel PCs vmware 64bits x86 VMware optimized virtual machine ion 64bits x86 nVidia ION systems x kbb Koala KBB 3 3 Certified Platforms While OpenBricks runs natively on all x86 computers the ARM PowerPC MIPS embedded space is obviously another story So far the OpenBricks project has been tested evaluated and certified with the following embedded platforms that we own PandaBoard OMAP4 BeagleBoard OMAP3 Nokia N900 OMAP
6. SI do_installdev usr include do_installdev usr lib 7 3 6 Helper functions setup_toolchain lt target host gt sets several environment variables such as CFLAGS to prepare for a host build using HOST_CC or for a target build using STARGET_CC setup_toolchain target is automatically called before a pack age build so it s not necessary to explicitly use for normal package builds get_meta lt package gt retrieves a package meta file and sources it into the environment doing several safety checks some postprocessing and setting additional variables pkg_uses lt package gt lt use_flag gt returns true if the specified use flag is currently enabled for the package and false otherwise kernel_path returns the path to the kernel build tree which can be useful to build out of tree kernel modules kernel_version returns the kernel version require_glibc lt package gt aborts build if TARGET_LIBC is not a glibc variant require_cxx lt package gt aborts build if C support is not enabled do_qmake invokes qmake with the correct setup for a cross build do_strip bin shlib staticlib lt path gt strips the argument after checking that it is actually an ELF object file the first optional argument which defaults to bin sets the correct strip options for the target OpenBricks Embedded Linux Framework User Manual 25 36 extract_debug_info lt debug_path gt lt unstripped_files gt uses objdump to create detached d
7. The package unpack directory can be referenced reading PKG_BUILD_DIR after a get_meta call for most packages where the standard unpack works it is also possible to use BUILD 1 though it could lead to conflicts in case of multiple packages with similar names 7 3 3 build script The build script is responsible for the package build which for most packages entails a compilation from source The script can be handwritten but there are several helper functions do_configure make_instal1l etc which can help to automate the most boring parts The compilation results should be installed in PKG_BUILD_DIR install to ease the following stages implementation Example bin sh config options cd BUILD 1 do_configure OpenBricks Embedded Linux Framework User Manual 24 36 make make_install 7 3 4 install script The install script gathers the files which should be copied to the target rootfs which is set as INSTALL If the build script has created a install directory it can be easily written using the do_instal1 function Example bin sh EONO EONS cd SBUILD S 1 do_install usr bin do_install usr lib lib sox 7 3 5 installdev script The installdev script gathers the files which should be copied to the toolchain directory which is set as INSTALL If the build script has created a install directory it can be easily written using the do_installdev function Example bin sh config options el SIFU
8. and accepts any of the above attributes as options A choice can only be of type bool or tristate while a boolean choice only allows a single config entry to be selected a tristate choice also allows any number of config entries to be set to m This can be used if multiple drivers for a single hardware exists and only a single driver can be compiled loaded into the kernel but all drivers can be compiled as modules A choice accepts another option optional which allows to set the choice to n and no entry needs to be selected comment comment lt prompt gt lt comment options gt This defines a comment which is displayed to the user during the configuration process and is also echoed to the output files The only possible options are dependencies menu menu lt prompt gt lt menu options gt lt menu block gt endmenu This defines a menu block see Menu structure above for more information The only possible options are dependencies if if lt expr gt lt if block gt endif This defines an if block The dependency expression lt expr gt is appended to all enclosed menu entries source source lt prompt gt This reads the specified configuration file This file is always parsed mainmenu mainmenu lt prompt gt This sets the config program s title bar if the config program chooses to use it OpenBricks Embedded Linux Framework User Manual 31 36 A 7 Kconfig hints This is a collection
9. but every definition can have only a single input prompt and the type must not conflict OpenBricks Embedded Linux Framework User Manual 27 36 A 3 Menu attributes A menu entry can have a number of attributes Not all of them are applicable everywhere see syntax e type definition bool tristate string hex int Every config option must have a type There are only two basic types tristate and string the other types are based on these two The type definition optionally accepts an input prompt so these two examples are equivalent bool Networking support and bool prompt Networking support e input prompt prompt lt prompt gt if lt expr gt Every menu entry can have at most one prompt which is used to display to the user Optionally dependencies only for this prompt can be added with if e default value default lt expr gt if lt expr gt A config option can have any number of default values If multiple default values are visible only the first defined one is active Default values are not limited to the menu entry where they are defined This means the default can be defined somewhere else or be overridden by an earlier definition The default value is only assigned to the config symbol if no other value was set by the user via the input prompt above If an input prompt is visible the default value is presented to the user and can be overridden by him Optionally dependencies only for this defau
10. of Kconfig tips most of which aren t obvious at first glance and most of which have become idioms in several Kconfig files A 7 1 Adding common features and make the usage configurable It is a common idiom to implement a feature functionality that are relevant for some architectures but not all The recommended way to do so is to use a config variable named HAVE_ that is defined in a common Kconfig file and selected by the relevant architectures An example is the generic IOMAP functionality We would in lib Kconfig see Generic IOMAP is used to config HAVE_GENERIC_IOMAP config GENERIC_IOMAP depends on HAVE_GENERIC_IOMAP amp amp FOO And in lib Makefile we would see obj CONFIG_GENERIC_IOMAP iomap o For each architecture using the generic IOMAP functionality we would see config X86 select select HAVE_GENERIC_IOMAP select Note we use the existing config option and avoid creating a new config variable to select HAVE_GENERIC_IOMAP Note the use of the internal config variable HAVE_GENERIC_IOMAF it is introduced to overcome the limitation of select which will force a config option to y no matter the dependencies The dependencies are moved to the symbol GENERIC_IOMAP and we avoid the situation where select forces a symbol equals to y A 7 2 Build as module only To restrict a component build to module only qualify its config symb
11. 3 TI OmapZoom 2 OMAP3 ISEE IGEPv2 OMAP3 AlwaysInnovating TouchBook OMAP3 nVidia Harmony Tegra250 ST Ericsson Snowball U8500 SolidRun CuBox Armada 510 Raspberry Pi BCM2708 OpenBricks Embedded Linux Framework User Manual 8 36 Chapter 4 OpenBricks Toolchain Overview A toolchain is a set of tools used to compile link assemble source files into some kind of binary format that your processor can interpret By definition each type of architecture x86 PowerPC ARM or processor has its specific instruction set on top of which can also be added some extra SIMD instructions A toolchain is meant to compile source into a code understandable by the target CPU it ll be running on When working with embedded devices the target architecture is often different from the one you re currently working on referred as host As a result we often speak about cross compiler suite as the compiling tools are meant to run on host architecture and must produced target architecture compatible binaries The toolchain must contain all the necessary tools libs and headers for building bare Linux applications It usually consists of e GNU Binutils e GNU GCC e AC library eglibc glibc uClibc e Linux kernel headers Nearly all desktop Linux distributions are provided with their native toolchain It s being used to compile programs for your system Nearly none of them however comes with an available cr
12. 3 2 Available Platforms A platform in OpenBricks terminology is a subset of a given hardware architecture It can vary from a specific SoC or mi croprocessor brand to a dedicated embedded board Each platform may have some specific configuration and tuning either hardware or software but once certified to work with OpenBricks it means that every owner of such a platform is ensured that the OpenBricks project will run on it The OpenBricks project is continuously trying to support as much platforms as possible and donating sponsoring is the best way to have new ones being supported The exhaustive list of supported platforms can be found config platform arch directory So far the OpenBricks project is available on the following platforms e ARM OpenBricks Embedded Linux Framework User Manual bemring Broadcom BCM11107 boards x bem11107 Broadcom BCM11107 evaluation board bcm2708 Broadcom BCM2708 boards x raspberrypi Raspberry Pi imx5x Freescale iMX5x boards efikamx Genesi Efika MX mx51 evk i MX51 Evaluation Kit x mx53 evk i MX53 Evaluation Kit imx6 Freescale 1 MX6 boards x arm2 Freescale i MX6Q Armadillo2 x Sabrelite Freescale iMX6Q SabreLite x sabresd Freescale i MX6Q SabreSD kirkwood All Marvell Kirkwood equipped boards Sheevaplug Marvell SheevaPlug omap3 All TI OMAP3 equipped boards x beagleboard BeagleBoard igepv2 ISEE IGEPv2 n900 Nokia N900 tao3530
13. C The GNU Multiple Precision Arithmetic Library PKG_LONGDESC GMP is a free library for arbitrary precision arithmetic operating on signed gt integers rational numbers and floating point numbers There is no practical limit to the precision except the ones implied by the available memory in the machine GMP runs on gt GMP has a rich set of functions and the functions have a regular interface A standard runtime package Ae KG_NAME lsof KG_VERSION 4 83 KG_URL http ftp cerias purdue edu pub tools unix sysutils lsof lsof_ PKG_VERSION tar 4 longa KG_REV 1 KG_RUN_DEPENDS TARGET_LIBC KG_BUILD_DEPENDS toolchain KG_PRIORITY optional ty iam OpenBricks Embedded Linux Framework User Manual PKG_SECTION utils PKG_SHORTDESC List open files PKG_LONGDESC Lsof is a Unix specific diagnostic tool and it does just that processes currently running on the system It lists information about any files that are open 22 36 Its name stands for LiSt Open Files gt loi Note the use of TARGET_LIBC in PKG_DEPENDS to refer to the runtime system libc which could be uClibc glibc or eglibc A non free package available only on selected archs PKG_NAME xf86 video nvidia RSION 340 76 RGET_ARCH 1386 _URL f PKG _ VERSION run RGET_ARCH x86_64 _ URL x86_64 S PKG_VERSION no compat32 run PKG_REV 1 PKG_FORC
14. E _SECTION_DESC_ section the user visible section name PKG _USE_SECTION_KCONFIG_hwaccel an optional block of Kconfig instructions which will be rendered in the section menu defaults to 6 3 7 Packages Packages are defined by meta files under the packages directory The Packages menu in Kconfig is created by reading the meta files and grouping the packages by sections Please refer to package format txt for more details on packages creation OpenBricks Embedded Linux Framework User Manual 16 36 Chapter 7 OpenBricks Package Structure 7 1 Introduction OpenBricks packages live under the packages directory in the source tree Every package is composed of several elements Most packages only use a small subset of these elements runtime programs usually have just meta build and install while meta package metadata information file url where the package sources can be downloaded from mostly obsoleted by PKG_URL field in meta need_unpack a shell script run before unpack stage usually to check for missing depends unpack a shell script run after unpack stage usually to postprocess the source or manually unpack packages which require special handling build a shell script which takes care of building the package from source install a shell script run to construct the runtime opkg package installdev a shell script run to construct the devel opkg package config a directory for misc configuration
15. E_CHECK true PKG_ARCH i386 x86_64 PKG_LICENSE non free PKG_DEPENDS xorg server PKG_BUILD_DEPENDS toolchain PKG_RUN_DEPENDS STARGET_LIBC kmod PKG_USE vdpau PKG_PRIORITY optional PKG_SECTION x11 amp amp E amp amp tp download nvidia com XFree86 Linux x86 PKG_VERSION NVIDIA Linux x86 S tp download nvidia com XFree86 Linux x86_64 PKG_VERSION NVIDIA Linux gt PKG_SHORTDESC NVIDIA binary Xorg driver PKG_LONGDESC These binary drivers provide optimized hardware acceleration of OpenGL gt applications via a direct rendering X Server AGP PCIe SLI TV out and flat panel lt displays are also supported Version for GeForce 8xxx cards A complex package which shows the usage of conditionals to define the depends PKG_NAME MP layer PKG_VERSTION 1 1 1 PKG_URL http www mplayerhq hu MPlayer releases MPlayer S PKG_VERSION tar xz PKG_URL_PROTO svn PKG_URL svn svn mplayerhq hu mplayer trunk PKG_REV 1 PKG_DEPENDS zlib ffmpeg freetype alsa lib fribidi libcdio faad2 libpng enca libass lt fontconfig libvorbis libtheora libmad lame PKG_BUILD_DEPENDS toolchain yasm lame PKG_RUN_DEPENDS STARGET_LIBC PKG_USE uclibc vaapi vdpau sdl xorg unrar live dvd bluray dvb
16. OpenBricks Embedded Linux Framework User Manual OpenBricks Embedded Linux Framework User Manual POF EY OBLATEX OpenBricks Embedded Linux Framework User Manual Contents 1 OpenBricks Introduction Ll 1 2 13 1 4 LS Whatisit Which hardware is supported What does the software offer 2 List of supported features 2 1 Key Features 454 4 4 2 2 Applicative Toolkits 2 3 Graphic Extensions 2 4 Video Extensions 2 5 Audio Extensions 2 6 MediaPlayers 2 7 Key Audio Video Profiles 2 8 Networking Features 2 9 Supported Filesystems 2 10 Toolchain Features 3 OpenBricks Supported Platforms a1 32 33 Supported Hardware AfchitectiesS lt s s scos eR GA R EG E OEE E EE A R e Available Platforms Certified Platforms 4 OpenBricks Toolchain Overview 5 OpenBricks Build Instructions OpenBricks Embedded Linux Framework User Manual 6 OpenBricks Configuration System 6 1 Tnirod tion gt s sce e os 6 2 Kconfig syntax 6 3 Configuration menu elements 63 1 Flavours 6 3 2 Architectures 6 3 3 Platforms 6 3 4 Machines 63 5 Remotes oio ess 636 Feats 2 6 3 7 Packages 7 OpenBricks Package Structure 7 1 Introduction se o 6 ew 7 2 MetaFile Format 72 1 Use Flags 55 7 2 2 Repository Download 7 2 3 Subpackages 7 2 4 Meta Examples
17. RL_PROTO only a single URL must be given Example PKG_URL_PROTO git PKG_URL git kernel ubuntu com ubuntu ubuntu natty git PKG_URL_REV cefe94dc5d171940edd23081d9d481dcled5824b PKG_VERSTION 2 6 38 natty PKG_URL_REV OpenBricks Embedded Linux 7 2 3 Subpackages A subpackage is a special kind of runtime package which packages an optional component of another package and is created from its install tree A subpackage has an additional mandatory field in meta e PKG_PARENT the name of the parent package i e the package this subpackage should be built from defaults to empty A subpackage has two additional optional fields in meta e PKG_PARENT_USE alist of use flags of the parent package the subpackage will be selectable in Kconfig only if all the use flags specified are active defaults to no use flags e PKG_NO_PARENT_DEPENDS whether the package should automatically build depend on its parent or not boolean field defaults to yes For clarity it is recommended but not required to name a subpackage as PKG_PARENT subpackagename 7 2 4 Meta Examples A devel only package PKG_NAME gmp case STOOLCHAIN_FLAVOR in next PKG_VERSION 6 0 0a TT PKG_VERSION 6 0 0a esac PKG_URL http ftp gnu org gnu PKG_NAME PKG_NAME PKG_VERSION tar xz PKG_REV 1 PKG_PRIORITY optional PKG_SECTION libs PKG_BUILD_DEPENDS toolchain PKG_SHORTDES
18. S JFS XFS GFS2 OCFS2 FUSE ISO9660 Joliet UDF FAT 16 FAT32 NTFS 2 10 Toolchain Features Supported Target Languages C C Python Complete Cross Compiler and Sysroot generation Support for external CodeSourcery toolchain for ARM targets Modularized distribution Multiple supported C libraries eglibc glibc uClibce SIMD Optimizations NEON VFP AltiVec MMX SSE Generic CPU support or target specific fine tuning optimizations OPKG Packaging Support for extra proprietary additions drivers firmwares 4 36 OpenBricks Embedded Linux Framework User Manual 5 36 Chapter 3 OpenBricks Supported Platforms 3 1 Supported Hardware Architectures The OpenBricks framework aims are enabling embedded Linux distribution creation for as much hardware architectures as possible It currently supports at least the following ones e ARM ARMv7 Cortex A9 with NEON extensions such as TI OMAP4 ARMv7 Cortex A9 such as nVidia Tegra250 ARMv7 Cortex A9 with optional VFP3 extensions such as Marvell Armada 510 ARMv7 Cortex A8 with NEON extensions such as TI OMAP3 ARMv6 ARM11 with optional VFP2 extensions such as Broadcom BCM2708 ARMv6 ARM11 with optional VFP extensions such as Broadcom BCMring ARMv5 ARM9 such as Marvell Kirkwood ARMv4t ARM9TDMD such as Samsung S3C24xx e x86 32 and 64 bits From i586 to Core i7 PowerPC MIPS
19. anual 36 36 Appendix F Adding a new distribution flavour Distribution flavours are defined in config flavours flavour To add a new flavour example you can follow these instructions 1 mkdir config flavours example 2 create config flavours example meta with a text editor with the following contents LAVOUR_NAME example LAVOUR_DISTRONAME Example Flavour LAVOUR_DEPENDS LAVOUR_USE LAVOUR_SHORTDESC my example flavour AAVOUR_LONGDESC a detailed description of my example flavour Ica Tea deal teal Teal teal 1 add the list of packages you want to select in your flavour to FLAVOUR_DEPENDS have a look at the existing flavours especially base which is a minimal console only system for examples of package combinations 2 optionally add arch specific packages to FLAVOUR_DEPENDS_ arch 3 optionally add platform specific packages to FLAVOUR_DEPENDS_ arch_ platform 4 add the list of features i e use flags you want to enable to FLAVOUR_USE 5 optionally add a BusyBox configuration file as busybox conf to customize BusyBox configuration After creating the meta file the new flavour will be available for selection in the OpenBricks configuration system If you believe your flavour can be of general usage we encourage you to submit it to the OpenBricks mailing list for review and inclusion in the upstream tree
20. ct the package in the configuration system and build an image with it OpenBricks Embedded Linux Framework User Manual 33 36 Appendix C Adding a new architecture Architectures are defined in config plaform To add support for a new architecture start by creating a subdirectory with you arch name and edit the meta file using one of the existing architectures as example After defining the arch you should also add generic platform and machine definitions OpenBricks Embedded Linux Framework User Manual 34 36 Appendix D Adding a new platform Platforms are defined in config plaform arch platform To add support for a new platform you should copy the generic platform for your arch cp PR config plaform myarch generic config plaform myarch myplatform and edit meta to change the platform settings At this point you have to decide if you want to use the OpenBricks kernel or a vendor supplied kernel In the first case you can add arch specific patches to packages linux patches or if they break other archs platforms to config plaform myarch my platform packages linux patches You should also add a tuned kernel config for your platform as linux conf in the platform directory If you want to use a vendor kernel you need to override the linux and linux headers packages Create config plaform myarch my platform packages linux meta with PKG_VERSION and PKG_URL pointing to your kernel and config plaform myarch myplatform pa
21. ebug symbols in debug_path for the specified files strip_libs lt path gt debug_path calls do_strip shlib if debug_path is set also calls ext ract_debug_info strip_bins lt path gt debug_path calls do_strip bin if debug_path is set also calls ext ract_debug_info xorg_drv_configure_prepend fixes the include files for Xorg drivers fix_libs lt path gt toolchain sysroot libprefix rewrites the prefix path in pkgconfig and library files for the specified target which defaults to Libprefix make_install toolchain sysroot libprefix unstripped is an automagic function to ease the installation of packages us ing autotools runs make install using PKG_BUILD_DIR install as install prefix calls ix_libs to set the correct prefix paths for libraries calls strip_libs and strip_bins to strip ELF files and place detached debug symbols in PKG_BUILD_DIRZ install debuginfo do_configure host target configure_options is an automagic function to ease the configuration of packages using autotools it sets up the enviroment for a host or target build and calls configure with the correct arguments do_install lt file gt is used in the package install script to copy to INSTALL the specified file which can include globbing from PKG_BUILD_DIRZ install do_installdev lt file gt toolchain sysroot libprefix is used in the package installdev script to copy to the requested target the specified file which can include globbin
22. ecome invisible if the parent is set ton e the child entry must only be visible if the parent is visible config MODULES bool Enable loadable module support config MODVERSIONS bool Set version information on all module symbols depends on MODULES comment module support disabled depends on MODULES MODVERSIONS directly depends on MODULES this means it s only visible if MODULES is different from n The comment on the other hand is always visible when MODULES is visible the empty dependency of MODULES is also part of the comment dependencies A 6 Kconfig syntax The configuration file describes a series of menu entries where every line starts with a keyword except help texts The following keywords end a menu entry config menuconfig choice endchoice comment menu endmenu if endif source OpenBricks Embedded Linux Framework User Manual 30 36 The first five also start the definition of a menu entry config config lt symbol gt lt config options gt This defines a config symbol lt symbol gt and accepts any of above attributes as options menuconfig menuconfig lt symbol gt lt config options gt This is similar to the simple config entry above but it also gives a hint to front ends that all suboptions should be displayed as a separate list of options choices choice lt choice options gt lt choice block gt endchoice This defines a choice group
23. ery equivalent but is much more versatile It can also allows you to choose which C library to use depending on your needs It also completely matches the runtime libraries so you really won t have any runtime surprises The OpenBricks toolchain is set as the default toolchain The toolchain to be used can be selected through make menuconfig Go to General settings Toolchain settings Toolchain and select the one you d like to use OpenBricks Embedded Linux Framework User Manual 9 36 Chapter 5 OpenBricks Build Instructions OpenBricks is meant for you to be able to create a fully customized system It can build nearly anything you want and assemble the system of your dreams but it needs to be configured for that first After having fetch the OpenBricks sources the very first thing to do is to start the configuration You may proceed by doing the following make menuconfig From there you may want to select the kind of distribution flavour you want to build The flavour is only a pre defined configu ration but you can obviously completely customize it By General setup menu you may want to configure the target architecture and platform you want to build your distribution for e g x86 ION system or ARM OMAP4 board Depending on your build system you may want to increase the concurrency make level as to use a maximum number of CPU cores to fasten the build process If you work in a company and have multiple developers work
24. ev package is installed defaults to PKG_BUILD_DEPENDS A runtime package has the same mandatory fields of a devel only package plus PKG_RUN_DEPENDS the runtime package dependencies i e the packages required to be able to run the package will be packaged and installed to the target system before the package is installed defaults to no runtime depends PKG_USE alist of use flags the package can handle see section USE FLAGS for more details defaults to no use flags PKG_REQUIRES_USE alist of use flags the package requires to be enabled you can also specify per package useflags with the package flag syntax see section USE FLAGS for more details defaults to no required use flags PKG_PRIORITY the package priority i e how much the package is important can be required the system will not boot without this package e g linux standard this package is part of the OpenBricks base system optional normal priority for packages not part of OpenBricks base system extra this is a minor non essential package PKG_SECTION the package category used to group packages by function can be admin tools and program useful for system administration drivers kernel or userspace drivers for hardware filesystem filesystem support drivers and programs games leisure programs libs shared libraries used by other prog
25. files used by the package unit a directory for systemd units package a directory for custom opkg control files e g prerm scripts patches a directory containing patches in diff Naur format to be applied after unpack and before build scripts a directory for misc shell scripts used by the package sources a directory for package sources which will be copied verbatim to the package build directory at unpack stage tmpfiles d a directory for systemd tmpfiles configuration files modules load d a directory for configuration files to list the kernel modules to load at boot modprobe d a directory for kernel module options configuration files libraries tend to also use installdev for includes and such OpenBricks Embedded Linux Framework User Manual 17 36 7 2 Meta File Format The meta file is used to provide the package metadata information hence the name It is a POSIX shell script which is sourced by the build system it can contain variable assignments and conditional instructions A devel only package e g gmp gcc core has three mandatory fields PKG_NAME the name of the package must coincide with the package directory name can be different from the upstream tarball name will be used to create the package build directory PKG_VERSION the upstream package current version will be used to create the package build directory PKG_REV the OpenBricks package revision i
26. g from PKG_BUILD_DIR install OpenBricks Embedded Linux Framework User Manual 26 36 Appendix A Understanding Kconfig File Format A 1 Introduction The configuration database is a collection of configuration options organized in a tree structure Code maturity level options Prompt for development and or incomplete code drivers General setup Networking support System V IPC BSD Process Accounting t Sysctl support Loadable module support Enable loadable module support Set version information on all module symbols Kernel module loader Every entry has its own dependencies These dependencies are used to determine the visibility of an entry Any child entry is only visible if its parent entry is also visible A 2 Menu entries Most entries define a config option all other entries help to organize them A single configuration option is defined like this config MODVERSIONS bool Set version information on all module symbols depends on MODULES help Usually modules have to be recompiled whenever you switch to a new kernel Every line starts with a key word and can be followed by multiple arguments config starts a new config entry The following lines define attributes for this config option Attributes can be the type of the config option input prompt dependencies help text and default values A config option can be defined multiple times with the same name
27. hat look for rapid board bring up with fine grain embedded Linux distribution setup with complete customization Ever had to care about BSP and toolchain That s now long gone history If time to market means for you OpenBricks will save your day 1 3 Which hardware is supported OpenBricks supports a broad range of embedded partners including but not limited to Intel TI nVidia Freescale Broadcom and Marvell and SoC from low end MIPS to high end ARM Cortex A9 MP through Intel ATOM Whether you re designing a smartphone a SetTopBox a NAS or a router OpenBricks can optimize your code for multi cores SMP multi threaded SMT hardware cryptographic accelerators various DSPs and SIMD extensions 1 4 What does the software offer OpenBricks reduces development efforts by abstracting the low level interface to your device It supports all Khronos industry standards OpenGLIES OpenVG OpenMAX and major applicative frameworks Qt GTK EFL SDL for you to only focus on your end user application 1 5 Who s using it OpenBricks is an OpenSource framework It s the masterpiece framework behind your next design product Anyone can use it and contribute to it individuals as well as professionals OpenBricks currently sustains the GeeXboX project OpenBricks Embedded Linux Framework User Manual Chapter 2 List of supported features 2 1 Key Features Fully Open Source and royalty free Multi Cores SMP optimizatio
28. he environment variable into Kconfig It behaves like a default except that the value comes from the environment this also means that the behaviour when mixing it with normal defaults is undefined at this point The symbol is currently not exported back to the build environment if this is desired it can be done via another symbol A 4 Menu dependencies Dependencies define the visibility of a menu entry and can also reduce the input range of tristate symbols The tristate logic used in the expressions uses one more state than normal boolean logic to express the module state Dependency expressions have the following syntax lt expr gt lt symbol gt lt symbol gt lt symbol gt lt symbol gt lt symbol gt lt expr gt l lt expr gt lt expr gt amp amp lt expr gt lt expr gt lt expr gt UA OB WBN EF Expressions are listed in decreasing order of precedence 1 Convert the symbol into an expression Boolean and tristate symbols are simply converted into the respective expression values All other symbol types result in n N If the values of both symbols are equal it returns y otherwise n If the values of both symbols are equal it returns n otherwise y Returns the value of the expression Used to override precedence Returns the result of 2 expr Returns the result of min expr expr YN A NA A W Returns the result of max ex
29. he usefulness but on the other hand avoid the illegal configurations all over kconfig should one day warn about such things OpenBricks Embedded Linux Framework User Manual 28 36 numerical ranges range lt symbol gt lt symbol gt if lt expr gt This allows to limit the range of possible input values for int and hex symbols The user can only input a value which is larger than or equal to the first symbol and smaller than or equal to the second symbol help text help or help This defines a help text The end of the help text is determined by the indentation level this means it ends at the first line which has a smaller indentation than the first line of the help text help and help do not differ in behaviour help is used to help visually separate configuration logic from help within the file as an aid to developers e misc options option lt symbol gt lt value gt Various less common options can be defined via this option syntax which can modify the behaviour of the menu entry and its config symbol These options are currently possible defconfig_list This declares a list of default entries which can be used when looking for the default configuration which is used when the main config doesn t exists yet modules This declares the symbol to be used as the MODULES symbol which enables the third modular state for all config symbols env lt value gt This imports t
30. headers meta with a matching PKG_VERSION If your platform uses u boot you can add platform specific bootargs to config plaform myarch myplatform boot cfg OpenBricks Embedded Linux Framework User Manual 35 36 Appendix E Adding a new machine Machines are defined per platform in config plaform arch platform machines To add support for a new machine you should copy an existing machine definition such as the generic machine for your arch cp PR config plaform myarch myplatform ma chines generic config plaform myarch myplatform machines and edit meta to change the machine settings At this point you have to decide if you want to use the OpenBricks kernel or a vendor supplied kernel In the first case you can add arch specific patches to packages linux patches or if they break other archs platforms to config plaform myarch my platform packages linux patches You should also add a tuned kernel config for your platform as linux conf in the platform directory If you want to use a vendor kernel you need to override the linux and linux headers packages Create config plaform myarch my platform packages linux meta with PKG_VERSION and PKG_URL pointing to your kernel and config plaform myarch myplatform pa headers meta with a matching PKG_VERSION If your machine uses u boot you can add machine specific bootargs to config plaform myarch myplatform machines myma chine boot cfg OpenBricks Embedded Linux Framework User M
31. ing on the same LAN you may also want to specify a previously setup mirror server for packages tarball sources to be downloaded from instead of going on the Internet each time Next thing is to configure the various settings and the target images You may want to build either a traditional rootfs a bootable ISO for LiveCD or a network capable PXE aware filesystem Also possible is to configure the localization support Feel free after that to proceed with fine tuning by selecting the features and packages you want to be included Dependancies are automatically handled so that you shouldn t have to vary about the whole system s consistency Once satisfied exit the configuration menu and make sure to save all of your changes The resulting config options file should now have been generated That s it you re ready to build Just make at shell prompt and wait for a couple hours depending on the packages and configura tion you have chosen For a exhaustive list of supported commands you may have a look at the top level Makefile but the main options are make proceed with a complete build of your distribution make clean clean up all build files make clean doc clean up the documentation make dist create a tarball of all your sources ready for distribution make distclean clean up all build files documentation and external tarballs make doc cleanup the generated documentation files make get retrieve all tarballs a
32. latforms2kconfig config platforms meta General setup Target platform Kconfig machine scripts machines2kconfig config platforms machines Gemetal setup Target machine Kconfig remote scripts remotes2kconfig packages lirc config lircd Settings Remote Settings Receiver Kconfig use scripts use2kconfig config use Features Kconfig packages scripts meta2kconfig packages meta Packages After the user has completed the configuration selections a config file is created The config file is used by scripts kcon fig2options to create build config options which is the file actually used by the rest of the OpenBricks build system it is sourced through config options OpenBricks Embedded Linux Framework User Manual 12 36 6 2 Kconfig syntax For general informations about the Kconfig syntax refer to DOCS kconfig language txt In addition to the syntax specifications OpenBricks uses some conventions in its Kconfig files e hand written Kconfig entries e g TARGET_LIBC are in uppercase but subentries can be in lowercase e g TARGET_LIBC_eglibc e all entries starting with the OPT_ prefix are exported to build config options for example OPT_TOOLCHAIN_CXX y in config will become TOOLCHAIN_CXX yes in build config options e all features have a USE_feature entry e g USE_bluetooth e all packages have a PKG_package entry e g PKG_MPlayer 6 3 Configuration menu elements 6 3 1 Flavours
33. lt value can be added with if e type definition default value def_bool def_tristate lt expr gt if lt expr gt This is a shorthand notation for a type definition plus a value Optionally dependencies for this default value can be added with at e dependencies depends on lt expr gt This defines a dependency for this menu entry If multiple dependencies are defined they are connected with amp amp Dependencies are applied to all other options within this menu entry which also accept an if expression so these two examples are equivalent bool foo if BAR default y if BAR and depends on BAR bool foo default y e reverse dependencies select lt symbol gt if lt expr gt While normal dependencies reduce the upper limit of a symbol see below reverse dependencies can be used to force a lower limit of another symbol The value of the current menu symbol is used as the minimal value lt symbol gt can be set to If lt symbol gt is selected multiple times the limit is set to the largest selection Reverse dependencies can only be used with boolean or tristate symbols Note select should be used with care select will force a symbol to a value without visiting the dependencies By abusing select you are able to select a symbol FOO even if FOO depends on BAR that is not set In general use select only for non visible symbols no prompts anywhere and for symbols with no dependencies That will limit t
34. ncremented on every major change in the package reset to 1 every time PKG_VERSION changes A devel only package has several optional fields PKG_URL aspace separated list of URLs the package should be downloaded from can start with variable DISTRO_SRCS if the files are hosted on the OpenBricks server or with SFNET_SRCS if they are on SourceForge in addition URLs can be listed in the url file in the package directory all resources listed will be fetched PKG_URL can point to the location of a source code repository such as git Subversion svn or Mercurial hg when used together with PKG_URL_PROTO details are given in the section Repository Download below PKG_SHA256 aspace separated list of SHA 256 checksums of the package files the checksums will be checked against the downloaded files PKG_MD5 aspace separated list of MD5 checksums of the package files the checksums will be checked against the downloaded files PKG_BUILD_DEPENDS the build time package dependencies i e the packages required to be able to build the package will be packaged and installed to sysroot before the package is built defaults to no build depends PKG_DEV_DEPENDS the packages required to use the dev package e g gcc core needs binutils to work but requires gmp only to build OpenBricks Embedded Linux Framework User Manual 18 36 will be installed to sysroot before the d
35. nd package sources make iso build a LiveCD ISO image ready to be burned and used mostly usefull for x86 targets only make menuconfig start the curses based distribution configuration and customization menu OpenBricks Embedded Linux Framework User Manual 10 36 e make qemu runs your built up distribution image in QEMU emulator e make vmx build a VMware compatible virtual machine image only makes sense with x86 target build e make vmx play starts up the previously built virtual machine in VMware s vmplayer OpenBricks Embedded Linux Framework User Manual 11 36 Chapter 6 OpenBricks Configuration System 6 1 Introduction OpenBricks uses a Kconfig based interface to allow the user to customize the system to suit his requirements The configuration menu is built from several sources e the main Kconfig definition file config Kconfig main e the architecture Kconfig file config Kconfig arch e the generated Kconfig files build config Kconfig The following table details the various generated Kconfig files Table 6 1 Generated Kconfig files Keonfig file Creator script Source material Kconfig menu Kconfig version scripts version2kconfig VERSION Version header Kconfig flavours scripts flavours2kconfig config flavours meta Flavour Distribution name Kconfig arch scripts archs2kconfig config platforms meta General setup Target arch Kconfig platform scripts p
36. non free package may restrict the distribution of the entire distro if it is built in and may have unreasonable difficult to meet restrictions defaults to free 7 2 1 Use Flags In the context of a OpenBricks package a use flag represents a conditional feature which can be selected by the user at compile time and which could bring alongside additional depends Use flags are strictly per package flags enabled for package X do not affect flags for package Y Some flags e g xorg may be enabled or disabled distro wide with a config option but their value can still be customized for each package A package declares its available flags with PKG_USE in meta For each flag a package can declare several information all optional using the following per flag variables e PKG_USE_NAME flag the displayed name of the use flag defaults to flag e PKG_USE_DESC_ flag the short description of the flag defaults to Enable PKG_USE_NAME_ flag support OpenBricks Embedded Linux Framework User Manual 20 36 e PKG_USE_HELP_ flag the long description of the flag which is used as its help text in the configuration menu defaults to PKG_USE_DESC_ flag e PKG_USE_DEFAULT_S flag the default status of the flag i e if it s to be enabled or disabled note that a flag will automatically default to enabled status if the option USE_ flag is enabled this is used to globally toggle a flag status
37. ns Support for SMT HyperThreading Hardware Cryptographic Acceleration SHA1 MDS AES Support for TouchScreens Support for LIRC Infrared Remote Controls Highly efficient Parallelized init 2 2 Applicative Toolkits QT GTK EFL Enlightenment Foundation Libraries SDL Simple DirectMedia Layer 2 3 Graphic Extensions Native framebuffer Interface Accelerated DirectFB engine Accelerated X11 Infrastructure Desktop OpenGL 3 0 EGL Native Platform Graphics Interface Embedded OpenGLIES 2 1 Embedded OpenVG 1 0 2 36 OpenBricks Embedded Linux Framework User Manual 2 4 Video Extensions e Hardware DSP Acceleration e OpenMAX e VDPAU e VA API 2 5 Audio Extensions e ALSA e PulseAudio 2 6 Media Players e libplayer Audio Video abstraction framework e FFmpeg e MPlayer e Xine e GStreamer e VLC e VDR Video Disk Recorder 2 7 Key Audio Video Profiles e Video Codecs MPEG 1 2 4 H 264 Theora VC 1 VP8 e Audio Codecs MP3 Vorbis AAC AC 3 DTS e Protocols CDDA DVD DVB C S T V4L2 Bluray e Streaming RTP RTSP ASF MMS WebM 2 8 Networking Features Gigabit Support ConnMan network manager WiFi with WEP and or WPA 2 support BlueTooth Samba Client Server Automounter NFS Client Automounter Plan 9 Client Automounter UPnP DLNA support 3 36 OpenBricks Embedded Linux Framework User Manual 2 9 Supported Filesystems EXT 2 3 4 JBD ReiserF
38. ol with depends on m E g config FOO depends on BAR amp amp m limits FOO to module m or disabled n OpenBricks Embedded Linux Framework User Manual 32 36 Appendix B Adding a new package Packages are defined in packages package To easily add a new package you can use the newpackage tool which will create a skeleton package template for you to fill in Simply run scripts newpackage hello to create a package for the hello program The script will create a new hello directory under packages To quickly package your software 1 fill in the meta file fields starting from PKG_VERSION and PKG_URL 2 run scripts unpack hello to make sure package download is ok and check for the presence of hello PKG_VERSION directory in BUILD 3 check packages hello build and add additional configure options to the do_configure call for packages not using GNU autotools you may have to do more extensive customizations run scripts build hello and make sure the package builds with no errors check BUILD hello PKG_VERSION install to see which programs libraries should be installed in the target system edit packages hello install to select the files to install to the target system NY DH Nn A if you are packaging a library edit packages hello installdev to select the files that should be installed in toolchain other wise remove the file 8 run scripts clean hello to clean the package 9 try to sele
39. oot with boot cfg A platform can override any package by creating a directory with the package name i e config platforms arch platform packages pac This can be used e g to implement platform specific kernels in this case the plaform overrides the linux and linux headers packages Refer to the OMAP4 platform config platforms arm omap4 for an implementation example 6 3 4 Machines Machines are defined in the machines subdirectory in the platform directory each machine has a subdirectory Most settings are defined in the meta file e MACHINE NAME the name of the machine must coincide with the machine directory name e MACHINE DESC the user visible name of the machine will be displayed in the Kconfig menu defaults to MACHINE NAME e MACHINE CPU the default CPU to be selected defaults to no selection e MACHINE_DEPENDS the packages the machine requires to be installed defaults to no package e MACHINE UBOOT_CONFIG the name of the u boot configuration to be used defaults to no configuration e MACHINE_XLOADER_CONFIG the name of the X loader configuration to be used defaults to no configuration In addition a machine can declare a list of use flags in MACHINE_USE to be able to specify per useflag dependencies using MACHINE_DEPENDS_ flag A machine can also override the default kernel configuration with a linux conf file and the default boo
40. oss toolchain There are many different ways to generate a cross toolchain and some specific tools exist for that purpose All cross toolchains are not equivalent though They heavily vary depending on which versions of the previously mentionned tools they provide They also can be more or less customized as to add some specific patches fixes and optimizations for given architectures The OpenBricks project currently supports 2 different toolchains e The native OpenBricks toolchain The external ARM toolchain from CodeSourcery The external ARM toolchain from CodeSourcery is known to be the reference toolchain for ARM architecture It s heavily customized and optimized to provide the best performances It is being used by multiple projects mostly because it can be deployed and installed as it and can build pretty much everything you need It is commercially supported updated once a year but also often uses a bit more dated versions of each tool than the one you may find on your regular desktop distribution You may however have some issues when using different runtime system libs than the one used at build time as provided by the toolchain By opposition the native OpenBricks toolchain is mostly up to date and supports a much wider set of architectures The toolchain is actually part of our sources and dynamically built depending on the configuration options you have selected The toolchain is a bit less performance wide than the CodeSourc
41. pr expr An expression can have a value of n m or y or 0 1 2 respectively for calculations A menu entry becomes visible when its expression evaluates to m or y There are two types of symbols constant and non constant symbols Non constant symbols are the most common ones and are defined with the config statement Non constant symbols consist entirely of alphanumeric characters or underscores Constant symbols are only part of expressions Constant symbols are always surrounded by single or double quotes Within the quote any other character is allowed and the quotes can be escaped using OpenBricks Embedded Linux Framework User Manual 29 36 A 5 Menu structure The position of a menu entry in the tree is determined in two ways First it can be specified explicitly menu Network device support depends on NET config NETDEVICES endmenu All entries within the menu endmenu block become a submenu of Network device support All subentries inherit the dependencies from the menu entry e g this means the dependency NET is added to the dependency list of the config option NETDEVICES The other way to generate the menu structure is done by analyzing the dependencies If a menu entry somehow depends on the previous entry it can be made a submenu of it First the previous parent symbol must be part of the dependency list and then one of these two conditions must be true e the child entry must b
42. rams multimedia programs dealing with audio video or image contents net network clients servers and generic network related programs x perl Perl modules python Python modules sound programs dealing with audio support system essential system programs and libraries utils miscellaeous utility programs x11 programs and libraries related to the Xorg windowing system PKG_SHORTDESC OpenBricks Embedded Linux Framework User Manual 19 36 used as the short description for the package should be one line summary should not start with the package name e PKG_LONGDESC used as the long description for the package A regular package has the same optional fields of a devel only package plus e PKG_DEPENDS the package dependencies required both at build and at runtime shorthand for adding a package to both PKG_RUN_DEPENDS and PKG_BUILD_DEPENDS defaults to no depends e PKG_ARCH the target architectures supported by the package can be any the package is supported on all the available architectures x all this is an architecture independent package e g enna theme a spaced list of architecture names x defaults to any e PKG_LICENSE the upstream package license can be free the package is distributed under a DFSG compliant license i e GPL LGPL MIT etc x non free the package license does not meet the DFSG a
43. sh implementation such as dash is recommended e the script should source config options as their first action because of this the script will have access to all the variables and functions defined in config options config toolchain config path and config functions e scripts are expected to be called with the package name as the first argument this means 1 inside the script will refer to the package name e the script can use get_meta 1 to read the package meta if necessary directly sourcing the meta file is not recommended 7 3 1 need_unpack script The need_unpack script is executed just before the package unpack stage It can be used to ensure the prerequisites for the package are always satisfied It is normally used only for packages that require a kernel tree to build such as out of tree kernel drivers to make sure they are properly rebuilt if the kernel tree changes e g because of a kernel upgrade This is obtained by removing the unpack stamp for the package if the conditions are not satisfied which forces a full rebuild 7 3 2 unpack script The unpack script is executed just after the package unpack stage It can be used to postprocess the package sources e g fixing a broken upstream makefile with sed or to manually unpack the package sources e g for binary packages like xf86 video nvidia If necessary the helper function apply_patch lt package gt lt patch gt can be used to apply arbitrary patches to the package
44. targs for ARM systems using u boot with boot cfg A machine can override any package by creating a directory with the package name i e config platforms arch platform machines ma This can be used e g to implement machine specific bootloaders one example could be X loader which has no generic imple mentation and is machine specific OpenBricks Embedded Linux Framework User Manual 15 36 6 3 5 Remotes Remotes are defined by LIRC configuration files in packages lirc config and a Kconfig menu is created to allow the used to select the default remote and receiver to use 6 3 6 Features Features are defined in config use and implemented through use flags Packages can define package specific use flags but flags common to many packages or defining user visible features are declared in config use and exposed in the Kconfig interface in the Features menu Each feature is defined through several variables e PKG_USE_NAME flag the user visible feature name e PKG_USE_SECTION_ flag the section the feature should be placed into e PKG_USE_DEPENDS_ flag alist of packages the feature requires to be installed defaults to no packages e PKG_USE_ARCH_ flag alist of architecture the feature is defined for defaults to all architectures Features are grouped into sections which are rendered as separate menues in the Kconfig interface Sections are defined through several variables e PKG US
45. visible help text of the architecture will be displayed in the Kconfig menu e ARCH_SUBARCHS aspace separated list of sub architecture names as understood by gcc defaults to no subarchs e ARCH_CPUS aspace separated list of CPU names as understood by gcc these CPUs will be common to all the define subarchs The ARCH_DESC and ARCH_CPUS variables can also be defined for each subarch using ARCH_DESC_ subarch and ARCH_CPUS_ 6 3 3 Platforms Platforms are defined in config platforms every architecture has a subdirectory and all platforms have a subdirectory under one of the arch subdirectories Most settings are defined in a meta file e PLATFORM_NAME the name of the platform must coincide with the platform directory name e PLATFORM_DESC the user visible name of the platform will be displayed in the Kconfig menu defaults to PLATFORM_NAME e PLATFORM_CPU the default CPU to be selected defaults to no selection e PLATFORM_DEPENDS OpenBricks Embedded Linux Framework User Manual 14 36 the packages the platform requires to be installed defaults to no package In addition a platform can declare a list of use flags in PLATFORM_USE to be able to specify per useflag dependencies using PLATFORM_DEPENDS_ flag A platform can also override the default kernel configuration with a linux conf file and the default bootargs for ARM systems using u b
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