Yocto Reference Manual
Contents
1. PHYTEC Messtechnik GmbH 2015 L 813e_ 1 Contents List Of FIGUIES sina da VVVK V KVA A Nd KO R NR ANO P SK AKO KR AN OP RN KA LL Conventions Abbreviations and Acronyms cccccscccsccsscccsccecccecccecccescceccccsccescesscescees iii 1 The Yocto Project tits 1 O e Ul lt zs5sssosssskusoskdokkadkkadkkad kho ska ee 1 T2 a 1 T3 Vocabular OA N N N 2 E rr rer errr re 2 a OPOP OPOP ee O L res 2 PR Po NNN E a RARA 2 Mee LE I EE EEE EE UE ER RER ER EEE EPEE EEE EE ER CM 2 135 DISO OPP EE P PO PO O P PPP reese 2 l O 3 AE 3 A o nn nn sean nent n cere 3 1 5 Official Doc sas 3 Compatible Linux DistributiONns ccccccccsssssessessscsesssesvesseeseesessvesoceseeseeseessesseeseeses 4 Introduction to the Phytec BSP sv 5 Sal SAUCE add 5 A see 5 2111 PU E ai D 5 RO oa pao 5 Sele BSP Met DAL sense seen kk kedze 6 RP O 6 3 1 2 2 meta openembedded A 6 3 1 23 po o RSK 6 Bile AME CAH NRC no 7 3 1 2 5 meta phytec meta phy lt SOC gt ssssserserssenenerssnsssensrens 7 3 1 2 6 e lgewererrrerrrrererrerrrerrrrererrrrrrerrerrrer errr errr rerrer rrr er rrr er 7 3 2 Build COn UA 7 A A VAS OV 8 4 1 Setting Up The Host sor 8 4 2 Uta 8 43 SICESCOMP A o POCO ssis isss O 9 5 piyiinibcDocoMmentacO Nun dd oj 10 A A O EN EE EEEE E E 10 ee Basic Sade 666060 AA ent 10 5 3 V LA E DANO SO R O aeaea aaa aaa 11 54 Advanced Usage da 12 6 Working with Poky and Bitbake ccccccccsscccsccssccssccssc2. Pin EG Yocto Reference Manual Document No L 813e_1 Release No AM335x PD15 1 0 1 MX 6 PD15 1 0 Edition August 2015 A product of a PHYTEC Technology Holding company Yocto Reference Manual Copyrighted products are not explicitly indicated in this manual The absence of the trademark or and copyright symbols does not imply that a product is not protected Additionally registered patents and trademarks are similarly not expressly indicated in this manual The information in this document has been carefully checked and is considered to be entirely reliable However PHYTEC Messtechnik GmbH assumes no responsibility for any inaccuracies PHYTEC Messtechnik GmbH neither gives any guarantee nor accepts any liability whatsoever for consequential damages resulting from the use of this manual or its associated product PHYTEC Messtechnik GmbH reserves the right to alter the information contained herein without prior notification and accepts no responsibility for any damages that might result Additionally PHYTEC Messtechnik GmbH offers no guarantee nor accepts any liability for damages arising from the improper usage or improper installation of the hardware or software PHYTEC Messtechnik GmbH further reserves the right to alter the layout and or design of the hardware without prior notification and accepts no Liability for doing so Copyright 2015 PHYTEC Messtechnik GmbH D 55129 Mainz Rights including th
3. 1 to the conf local conf This is not necessary in all cases The compiler options will then be switched from FULL OPTIMIZATION to DEBUG OPTIMIZATION Have a look at the Poky source code for the default assignment of DEBUG OPTIMIZATION To start a cross debug session install the SDK as mentioned previously source the SDK environment and run gtcreator in the same shell If you do not use gtcreator you can directly call the arm lt gt gdb debugger instead which should be in your path after sourcing the environment script If you work with Qtcreator have a look in the appropriate documentation delivered with your product either QuickStart or Application Guide for information on how how to set up the toolchain When starting the debugger with your userspace application you will get a SIGILL an illegal instruction from the libcrypto Openssl probes for the system capabilities by trapping illegal instructions which will trigger GDB You can ignore this and hit continue c command You can ignore this stop by adding handle SIGILL nostop to your GDB startup script or in the Qcreator GDB configuration panel Secondly you might need to disable a security feature by adding set auto load safe path to the same startup script which will enable automatic loading of libraries from any location If you need to have native debugging you might want install the debug symbols on the target You can do this by adding the following line t
4. home share perm u w perm g w exec chown g w G sudo find home share perm u r perm g r exec chmod g r V The cache directory stores all stages of the build process Poky has quite an involved caching infrastructure It is also advisable to create a shared directory as all builds can access this cache directory called shared state cache Create the two directories on a drive where you have approximately 50 GB of space and assign the following two variables in your build conf local conf DL DIR lt your directory gt yocto downloads SSTATE DIR lt your_directory gt yocto_sstate If you want to know more about configuring your build have a look at the documented example settings sources poky meta yocto conf local conf sample sources poky meta yocto conf local conf sample extended PHYTEC Messtechnik GmbH 2015 L 813e 1 9 Yocto Reference Manual 5 phyLinux Documentation Documentation for version PD15 1 0 The phyLinux script is a basic management tool for Phytec Yocto BSP releases written in Python by Stefan M ller Klieser It is mainly a helper to get started with the BSP structure You can get all the BSP sources without the need of interacting with Repo or Git The phyLinux script has only one real dependency It requires the wget tool installed on your host It will also install the Repo tool in a global path usr local bin on your host PC You can install it to a different location man
5. r dizzy This will initialize a BSP which will track the latest development state From now on running repo sync in this folder will pull all the latest changes from our Git repositories 14 PHYTEC Messtechnik GmbH 2015 L 813e_1 Working with Poky and Bitbake 6 5 BSP Features of meta phytec and meta yogurt 6 5 1 Buildinfo The buildinfo task is a feature in our recipes which prints instructions to fetch the source code from the public repositories So you do not have to look into the recipes yourself To see the instructions e g for the barebox package execute bitbake barebox c buildinfo in your shell This will print something like mini HOWTO Use a local git repository to build barebox To get source code for this package and version barebox 2014 11 0 phy2 execute mkdir p git cd git git clone ssh git git phytec de barebox dev barebox cd git barebox git checkout b v2014 11 0 phy2 local_development 57b87aedbf0b6ae0eb0b858dd0c83411097c777a You now have two possible workflows for your changes 1 Work inside the git repository Copy and paste the following snippet to your local conf SRC_URI_pn barebox git HOME git barebox branch BRANCH SRCREV_pn barebox AUTOREV BRANCH_pn barebox v2014 11 0 phy2 local development After that you can recompile and deploy the package with bitbake barebox c compile bitbake barebox c deploy Note You have to commi
6. If you do not do that Yocto will not notice that the source code was modified So execute something like git status show modified files git diff show changed lines git commit a m dummy commit for yocto This command is important in your repository folder e g git barebox Try to compile your new changes Yocto will automatically notice that the source code was changed and fetches and configures everything from scratch bitbake barebox c compile If the build fails go back to the source directory fix the problem and recommit your changes If the build was successful you can deploy the barebox and even create a new SD card image bitbake barbox c deploy new barebox in e g deploy images phyflex imx6 2 barebox phyflex imx6 2 bin bitbake phytec hwbringup image new sd card image in e g deploy images phyflex imx6 2 phytec hwbringup image phyflex imx6 2 sdcard If you want to make additional changes just make another commit in the repository and rebuild the barebox again 6 6 5 3 Option 3 Use phyexternalsrc For more information on the phyexternalsrc class see section 6 5 1 Buildinfo PHYTEC Messtechnik GmbH 2015 L 813e_1 21 Yocto Reference Manual 6 6 6 Configuring the Kernel Run menuconfig from bitbake for your kernel This example assumes the TI kernel e g for AM335x boards bitbake c menuconfig linux ti Configure the kernel and run bitbake c savedefconfig linux ti Now navigate manual
7. and will be updated in future If you want to benefit from those changes and are in general satisfied with the userspace configuration it could be the best solution to create your own layer on top of Yogurt If you need to rework a lot of stuff and only need the basic hardware support from Phytec better copy meta yogurt rename it and adapt it to your needs You can also have a look at the OpenEmbedded layer index to find different distribution layers If you just need to add your own application to the image create your own layer In the following chapter we assume that we have an embedded project called racer which we willimplement using our Yogurt Linux distribution First we need to create a new layer Yocto provides a script for that If you set up the BSP and the shellis ready type yocto layer create racer Default options are fine for now Move the layer to the source directory mv meta racer sources Create a Git repository in this layer to track your changes cd sources meta racer git init amp amp git add amp amp git commit s Now you can add the layer to your build conf bblayers conf BBLAYERS BSPDIR sources meta racer 6 6 3 Adding existing Software Part 2 Now that you have created your own layer you have a second option to add existing software to existing image definitions Our standard image is defined in meta yogurt in meta yogurt recipes images images phytec hwbringup image bb In your laye
8. To get you started with the BSP we summarize some basic tasks from the Yocto official documentation At this point all common documentation about Yocto apllies 6 6 1 Adding existing Community Software or Libraries to the BSP Image To add another software to the image have a look at the openembedded layer index at http layers openembedded org layerindex You can search for a software project name and find out in which layer it can be found If it is in the meta openembedded or openembedded core layer the recipe is already in your build tree Check in build conf bblayers conf if the corresponding meta layer gets parsed to Bitbake Than you just add the software to your image by adding the following line into build conf local conf IMAGE INSTALL append lt software gt Please note the leading whitespace which is necessary for the append command 16 PHYTEC Messtechnik GmbH 2015 L 813e_1 Working with Poky and Bitbake If you want to add another layer to the build download it to sources and add it to the build conf bblayers conf file 6 6 2 Creating Your own Layer Creating your layer should be one of the first tasks when customizing the BSP You have two basic options You could either copy and rename our meta yogurt or you can create a new layer which will contain your changes Which way is the better solution depends on your usecase meta yogurt is our example of how to create a custom Linux distribution
9. age bitbake barbox c deploy new barebox in e g deploy images phyflex imx6 2 barebox bin bitbake phytec hwbringup image new sdcard image in e g deploy images phyflex imx6 2 phytec hwbringup image phyflex imx6 2 sdcard PHYTEC Messtechnik GmbH 2015 L 813e 1 19 Yocto Reference Manual MN This is the dirty way to alter the source code because you modify files in Yocto s territory If you execute a clean e g bitbake barebox c clean or Yocto refetches the source code all your changes are lost To avoid this you can create a patch and move it to a save location in your layer For recipes which do not use Git repositories to fetch the source code you may need to use quilt to manage the patch stack Execute these commands in in the devshell git add adds all new and modified files to git s staging area git commit m dummy commit to create a patch creates a commit with a not so useful commit message git format patch 1 o creates a patch of the last commit and saves it in your home folder Further resources http www yoctoproject org docs 1 7 dev manual dev manual html modifying temporary source code 6 6 5 2 Option 2 Safe and Clean Change SRC URI in local conf Pro Contra All changes are saved with Git A lot of working directories in build tmp glibc work lt machine gt lt package gt You have to commit every change before recompiling For each ch
10. ange the toolchain compiles everything from scratch can be avoided with ccache First you need an external checkout of the Git repository of barebox or kernel and checkout the current branch If you do not have one use the commands mkdir git cd git git clone git git phytec de barebox cd barebox git checkout b v2015 02 0 phy remotes origin v2015 02 0 phy Add the following snippet to the file build conf local conf Use your own path to the git repository NOTE Branche name in variable BRANCH_pn barebox should be the same as the 20 PHYTEC Messtechnik GmbH 2015 L 813e_ 1 Working with Poky and Bitbake branch which is used in the repository folder Otherwise your commits won t be recognized later BRANCH_pn barebox v2015 02 0 phy SRC URI pn barebox git HOME git barebox branch BRANCH SRCREV pn barebox AUTOREV You also have to set the correct branch name in the file Either you create your own branch in the Git repository or use the default one here v2015 02 0 phy Now you should recompile the barebox from your own source bitbake barebox c clean bitbake barebox c compile Build should be successful because the source wasn t changed yet You you can alter the source in git barebox or for example the default defconfig e g git barebox arch arm configs imx_v7_defconfig After you are satisfied with your changes you have to make a dummy commit for Yocto
11. cnannnos 25 Yocto DociMentatioN cs sscssscsssecssscossenseonsecsscessesesacesanenae ee nee es aa en led alla land 26 Revisioni O ONDA 27 List of Figures Figure 1 E C o 6 eg o 10 eee neem nn MME enn oss oss aE aa 6 PHYTEC Messtechnik GmbH 2015 L 813e 1 Conventions Abbreviations and Acronyms Conventions Abbreviations and Acronyms This hardware manual describes the PB 00802 xxx Single Board Computer SBC in the following referred to as phyBOARD Wega AM335x The manual specifies the phyBOARD Wega AM335x s design and function Precise specifications for the Texas Instruments AM335x microcontrollers can be found in the Texas Instrumenten s AM335x Data Sheet and Technical Reference Manual Conventions The conventions used in this manual are as follows Text in blue italic indicates a hyperlink within or external to the document Click these links to quickly jump to the applicable URL part chapter table or figure Text in bold italic indicates an interaction by the user which is defined on the screen Text in Consolas indicates an input by the user without a premade text or button to click on Text in italic indicates proper names of development tools and corresponding controls windows tabs commands file paths etc used within the development tool no interaction takes place MIOS rm Shows the result of any user interaction command program execution etc A This is a warning It helps y
12. csccceccesccssccsccsscsescoeees 13 Gol Start o 13 6 2 IMAGES uvedu swnapemnnnupsmmnabsanmaunsauanuasbuneeueuneueNes 13 6 3 Aang TIE SON zadane AAA 14 6 4 Accessing Development States between Releases csccsecsscesccescescesceecescseeees 14 6 5 BSP Features of meta phytec and meta yogurt 15 6 5 1 BO bie cuneaeeeuiaeesaneaaceaeceancuamouanouanes 15 PHYTEC Messtechnik GmbH 2015 L 813e 1 1 Yocto Reference Manual 7 8 6 6 Customizing RU EBV Poe 0 BOS NO DIA 16 6 6 1 Adding existing Community Software or Libraries to the BSP Image 16 6 6 2 Creating Your own Layer iii 17 6 6 3 Adding existing A 17 6 6 4 Inspect Your Configuration en ra eee tn annee 18 6 6 5 Kernel and Barebox Configuration and Patching 18 6 6 5 1 Option 1 Quick and Dirty Modify before Configure Compile 19 6 6 5 2 Option 2 Safe and Clean Change SRC_URT in local conf 20 6 6 5 3 Option 3 Use phyexternalsrc 21 6 6 6 Configuring the Kernel 22 6 6 7 Apply the defconfig patch to the Kernel 22 6 7 AMO NAS oo A a a 23 6 7 1 Debugging a Userspace Application ccsccescsscesceecscesceeceseeescesceees 23 6 7 2 Generating Source Mirrors Working Offline 24 6 7 3 Compiling on the Target nin 24 6 7 4 Different Toolchains cid 25 6 7 5 Working with Kernel Modules oococcoccoccnccnccnocnncnnccnccnncnnconccnc
13. ec de smtpserverport 25 8 PHYTEC Messtechnik GmbH 2015 L 813e 1 Installation You should at least set name and email in your Git configuration otherwise bitbake will complain on the first build You can use the two commands to set them directly without editing gitconfig manually git config global user email your_email example com git config global user name name surname 4 3 site conf Setup Before starting the Yocto build it is advisable to configure the development setup Two things are most important the download directory and the cache directory It is not a precondition to do this but strongly recommended as it will help a lot with build times in the development process The download directory is a place where Yocto stores all sources fetched from the internet It can contain tar gz Git mirror or anything else It is very useful to set this to a common shared location on the machine Create this directory with 777 access rights To be able to share this directory between different users all files need to have group write access This will most probably be in conflict with default umask settings One possible solution would be to use ACLs for this directory sudo apt get install acl sudo setfacl R d m g rwx lt dl dir gt If you already created a download directory and want to fix the permissions afterwards you can do so with sudo find home share perm u w perm g w exec chmod g w V sudo find
14. el Development Manual e Yocto Development Manual The following examples will be either for the barebox or the kernel recipe but they can be adapted to barebox kernel and any other package in Yocto 18 PHYTEC Messtechnik GmbH 2015 L 813e_1 Working with Poky and Bitbake 6 6 5 1 Option 1 Quick and Dirty Modify before Configure Compile Pro Contra No overhead no extra Changes are easily overwritten by Yocto configuration Everything is lost Toolchain does not have to recompile everything It is possible to alter the source code before Bitbake configures and compiles the recipe You have to start with a clean phytec hwbringup image build so all working directories are on your disk Use Bitbake s devshell command to jump into the source directory of the recipe The barebox recipe is bitbake barebox c devshell After executing the command you can alter the source as you wish When you are finished exit the devshell by typing exit After leaving the devshell you can recompile the package bitbake barebox c compile force The extra argument force is important because Yocto does not recognize that the source code was changed Please note that you cannot execute the bitbake command in the devshell You have to leave it first If the build fails execute the devshell command again and fix it If the build is successful you can deploy the package and create a new SD card im
15. execute init after fetch o REPOREPO Use repo tool from another url x XML Use a local XML manifest u URL Manifest git url p PLATFORM Processor platform r RELEASE Release version After the execution of the init command phyLinux will print a few important notes and also information for the next steps in the build process 5 4 Advanced Usage phyLinux can be used to transport software states over any medium The state of the software is uniquely identified by the manifest xml You can create a manifest send it to another place and recover the software state with phyLinux init x manifest xml You can also create a Git repository containing your software states The Git repository needs to have branches other than master as we reserved the master branch for a different usage Use phyLinux to check out the states phyLinux u lt url of your git repo gt 12 PHYTEC Messtechnik GmbH 2015 L 813e_1 Working with Poky and Bitbake 6 Working with Poky and Bitbake 6 1 Start the Build After you downloaded all the meta data with phyLinux init you have to set up the shell environment variables This needs to be done every time you open a new shell for starting builds We use the shell script provided by poky in its default configuration From the root of your project directory type source sources poky oe init build env The abbreviation for the source command is a single dot sources poky oe init build env The current
16. gt combined with yocto s combo layer poky meta openembedded meta gt5 gt repo s manifest repository phy2octo meta phytec meta phyimx6 meta phyam335x meta yogurt repo 6x manifest xml repo 6x manifest xml BSP Yocto i MX6 BSP Yocto AM335x External Repositories git git yoctoproject org yocto docs Phytec Repositories git git phytec de meta phytec git git yoctoproject org meta yocto git git phytec de meta phyimx6 git git yoctoproject org poky git git phytec de meta am335x git github com meta qt5 meta qt5 git git phytec de meta yogurt git git openembedded org meta openembedded git git phytec de phy2octo git git openembedded org bitbake git git openembedded org openembedded core Figure 1 BSP Yocto Repository Graph 3 1 2 1 Poky The Phytec BSP is build on top of Poky It comes with a specific version of it defined in Repo manifest It comes with a specific version of Bitbake The Openembedded core layer meta is used as a base for our Linux system 3 1 2 2 meta openembedded OpenEmbedded is a collection of different layers containing the meta description for a lot of open source software projects We ship all OpenEmbedded layers with our BSP but not all of them are activated Our example images pull several software packages generated from OpenEmbedded recipes 3 1 2 3 meta gt5 This layer provides a community supported integration of gt5 in Poky based rootfs and is integrated in ou
17. http www yoctoproject org docs current mega manual mega manual html 26 PHYTEC Messtechnik GmbH 2015 L 813e_1 Revision History 8 Revision History Changes in this manual 14 08 2015 Manual First edition L 813e_1 Describes the Phytec BSP release PD15 1 0 for i MX6 and AM335x products PHYTEC Messtechnik GmbH 2015 L 813e 1 27 Yocto Reference Manual 28 PHYTEC Messtechnik GmbH 2015 L 813e_1 Suggestions for Improvement Document Yocto Reference Manual Document number L 813e 1 August 2015 How would you improve this manual Did vou find any mistakes in this manual page Submitted by Customer number Name Company Address Return to PHYTEC Messtechnik GmbH Postfach 100403 D 55135 Mainz Germany Fax 49 6131 9221 33 PHYTEC Messtechnik GmbH 2015 L 813e_1 Published by Pin CE PHYTEC Messtechnik GmbH 2015 Ordering No L 813e_1 Printed in Germany
18. interprets Recipes which contain code in Bitbake s own programming language Python and bash code The official documentation can be found here http www yoctoproject org docs current bitbake user manual bitbake user manual html 1 4 2 Toaster Toaster is a web frontend for Bitbake to investigate the build history and statistics It is planned that it grows into a build management frontend for Bitbake It is not yet complete in its features and under heavy development but you can already keep an eye on the project http www yoctoproject org docs current toaster manual toaster manual html toaster manual intro 1 5 Official Documentation For more general questions about Bitbake and Poky consult the mega manual http www yoctoproject org docs latest mega manual mega manual html PHYTEC Messtechnik GmbH 2015 L 813e 1 3 Yocto Reference Manual 2 Compatible Linux Distributions To build Yocto you need a compatible Linux host development machine The list of supported distributions can be found in the reference manual for the specific Yocto version For 1 7 it can be found here http www yoctoproject org docs 1 7 ref manual ref manual html detailed supported distros 4 PHYTEC Messtechnik GmbH 2015 L 813e 1 Introduction to Phytec s BSP 3 Introduction to the Phytec BSP 3 1 BSP Structure The BSP consists roughly of three parts BSP management BSP meta data and BSP content The management consists of repo and phyLi
19. ll be preselected and gives you a Starting point for implementing your own configuration A MACHINE defines a binary image which supports specific hardware combinations of module and baseboard Have a look at the machine conf file or our webpage for a description of the hardware PHYTEC Messtechnik GmbH 2015 L 813e 1 7 Yocto Reference Manual 4 Installation 4 1 Setting up the Host You need to have a running Linux distribution at your hand It should be running on a powerful machine as a lot of compiling will be done on it Yocto needs a handful of additional packages on your host For Ubuntu 14 04 you need sudo apt get install gawk wget git core diffstat unzip texinfo gcc multilib build essential chrpath socat libsdl1 2 dev xterm For the other distributions you can find information in the Yocto Quickstart http www yoctoproject org docs latest yocto project qs yocto project qs html 4 2 Git Configuration The BSP is heavily based on Git Git needs some information from you as a user to be able to identify which changes were done by whom If you do not have one create a gitconfig Here is an example user name lt Your Name gt email lt Your Mail gt phytec de core editor vim merge tool vimdiff alias co checkout br branch ci commit st status unstage reset HEAD last log 1 HEAD push default current color ui auto sendemail smtpserver idefix phyt
20. ly into the tmp work directory or run bitbake c devshell linux ti Copy the defconfig into your layer You now need to apply the defconfig to your build to have it permanently stored in your BSP modification 6 6 7 Apply the defconfig patch to the Kernel In your custom meta racer create a kernel recipe append recipes kernel linux linux ti_ bbappend This file needs to have an addition to the search path so that the patches used in this layer can be found by Bitbake FILESEXTRAPATHS prepend THISDIR The patches and configuration must then be added to the SRC_URI variable e g SRC_URI_append file defconfig file 0001 jump eeprom to 50 patch Y At this point Bitbake will search in the folder meta racer recipes kernel linux and some subfolders for the files listed in SRC_URI The path search order and OVERRIDE lookup order determine which defconfig will be used for the kernel 22 PHYTEC Messtechnik GmbH 2015 L 813e_1 Working with Poky and Bitbake 6 7 Common Tasks 6 7 1 Debugging a Userspace Application The phytec qt5demo image can be cross debugged without any change For cross debugging you just have to match the host sysroot with the image in use So you need to create a toolchain for your image with bitbake c populate_sdk phytec qt5demo image Additionally If you want to have full debug and backtrace capabilities for all programs and libraries in the image you could add DEBUG BUILD
21. n as wellas bash code 1 3 2 Classes Classes combine functionality used inside Recipes into reusable blocks 1 3 3 Layers A Layer is a collection of recipes classes and configuration metadata A layer can depend on other layers and can be included or excluded one by one It encapsulates a specific functionality and fulfills a specific purpose Each layer falls into a specific category Base Machine BSP Software Distribution Miscellaneous Yocto s versioning scheme is reflected in every layer as version branches For each Yocto version every layer has a named branch in its Git repository You can add one or many layers of each category in your build A collection of OpenEmbedded layers can be found here the search function is very helpful to see if a software package can be retrieved and integrated easily http layers openembedded org layerindex branch master layers 1 3 4 Machine Machines are configuration variables which describe the aspects of the target hardware 1 3 5 Distro Distribution describes the software configuration and comes with a set of software features 2 PHYTEC Messtechnik GmbH 2015 L 813e_1 The Yocto Project 1 4 Poky Poky is the reference system to define Yocto Project compatibility It combines several subprojects into releases Bitbake Toaster OpenEmbedded Core Yocto Documentation Yocto Reference BSP 1 4 1 Bitbake Bitbake is the task scheduler It is written in Python and
22. nf local conf If you comment out the line EXTRA_IMAGE_FEATURES debug tweaks the debug settings like setting an empty root password will not be applied 6 3 Installing the SDK To install the SDK for a machine and image type you can create an SDK installer with Bitbake in the BSP itself Ensure that the correct target machine is set You also need to pass the image type you want to create the SDKfor bitbake lt image gt c populate sdk This takes 1 5 hours depending on the image type and host machine like building a BSP After that you may find the installer in your Yocto directory under build deploy sdk Install the SDK with example yocto build deploy sdk poky glibc x86_64 phytec qt4demo image cortexa8t2hf vfp neon toolchain 1 7 sh Usage example with a simple C file named bumpRTS c source opt poky 1 7 environment setup cortexa8t2hf vfp neon poky linux gnueabi make bumpRTS Creates an arm binary file bumpRTS bumpRTS ELF 32 bit LSB executable ARM EABI5 version 1 SYSV dynamically linked uses shared libs for GNU Linux 2 6 32 BuildID sha1 42d4aa389d09ade2023364e4eef9021080f610f9 not stripped 6 4 Accessing Development States between Releases Special release manifests exist to give you access to current development states of the Yocto BSP They will not be displayed in the phyLinux selection menu but need to be selected manually This can be done by the following command line phyLinux
23. nux the meta data depends on the soc and describes how to build the software and the content are Phytec s Git repositories and external sources 3 1 1 BSP Management Yocto is an umbrella project Naturally this will force the user to base his work on several external repositories They need to be managed in a deterministic way The Repo tool is one way of managing Git repository tasks in a more comfortable way Phytec s Yocto BSP is managed with repo This provides us with a method to deliver fixed releases as well as rolling releases 3 1 1 1 phyLinux phyLinux is a wrapper for Repo to handle downloading an setting up the BSP with an out of the box experience 3 1 1 2 Repo Repo is a wrapper around the Repo tool set The phyLinux script will install the wrapper in a global path This is only a wrapper though Whenever you run repo init u lt url gt you first download the Repo tools from Googles Git server in a specific version to the repo repo directory Next time you run Repo all the commands will be available So be aware of the fact that the Repo version in different build directories can drift apart over the years if you don not run Repo sync Also if you store stuff for the archives you need to include the complete repo folder Repo expects a Git repository which will be parsed from the command line In case of our BSP we called it phy octo derived from Phytec s Yocto phyyocto phy octo In this repository the whole inf
24. o your conf local conf EXTRA_IMAGE_FEATURES dbg pkgs For cross debugging this is not required as the debug symbols will be loaded from the host side and the dbg pkgs are included in the SDK of your image anyway PHYTEC Messtechnik GmbH 2015 L 813e 1 23 Yocto Reference Manual 6 7 2 Generating Source Mirrors Working Offline Modify your site conf or local conf if you do not use a site conf as follows KDL DIR don t set it It will default to a directory inside build SOURCE_MIRROR_URL file home share yocto_downloads n INHERIT own mirrors BB_GENERATE_MIRROR_TARBALLS 1 Now run a bitbake c fetchall lt image gt for all images and for all machines you want to provide sources for This will create all necessary tar archives We can remove all SCM subfolders as they are duplicated with the tarballs rm rf build download git2 ECC Please consider that we used a local source mirror for generating the dl_dir and because of that some archives will be linked locally First we need to copy all files resolving symbolic links into the new mirror directory rsync val lt dl dir gt TOPDIR src_mirror Now we clean the build directory by deleting everything except build conf but including build conf sanity We change site conf as follows SOURCE MIRROR URL file TOPDIR src_mirror An INHERIT own mirrors BB_NO_NETWORK 1 SCONF_VERSION 1 The BSP directory can n
25. ome to the point where you either need to set some options for a kernel module or you want to blacklist a module Those things are handled by udev and go into conf files in etc modprobe d conf If you want to specify an option at buildtime there are three relevant variables If you just want to auto load a module which has e g no auto load capabilities add it to KERNEL_MODULE_AUTOLOAD your module either in the kernel recipe or in the global variable scope If you need to specify options for a module you can do so with KERNEL_MODULE_AUTOLOAD your module KERNEL_MODULE_PROBECONF your module module_conf_your module options your module parametername parametervalue If you want to blacklist a module from auto loading you can do it intuitively with KERNEL_MODULE_AUTOLOAD your module KERNEL_MODULE_PROBECONF your module module_conf_your module blacklist your module PHYTEC Messtechnik GmbH 2015 L 813e 1 25 Yocto Reference Manual 7 Yocto Documentation The most important piece of the documentation for a BSP user is probably the developer manual http www yoctoproject org docs current dev manual dev manual html Especially the chapter about common tasks is a good starting point http www yoctoproject org docs current dev manual dev manual html extendpoky The complete documentation is available in one single html page which is good for searching for a feature or a variable name
26. ormation about a software BSP release is stored in the form of a Repo xml manifest This data structure defines URLs of Git servers called remotes and Git repositories and it states called projects The Git repositories can be checked out in different states The revision field can be a branch tag or commit id of a repository So the state of the software is not necessarily unique e g the HEAD of a branch and can change over time That is the reason we use only tags or commit ids for our releases The state of the working directory is therefore unique and does not change The manifests for the releases have the same name as the release itself It is a unique identifier for the complete BSP The releases are sorted by SOC platform That is why you PHYTEC Messtechnik GmbH 2015 L 813e 1 5 Yocto Reference Manual have to choose the SOC you are using The selected SOC will define the branch of the phy octo Git repository which will be checked out for the manifest selection 3 1 2 BSP Meta Data We include several third party layers in our BSP to get a complete Linux distribution up and running without the need of integrating external projects at the beginning All used repositories are shown on the left of Figure 1 and are describe in the following section bitbake yocto docs meta yocto oe core Phytec s BSP Yocto AM335x i MX6 Git Repositories Dependency Graph Legend 3 gt normal git clone operation by repo 3
27. ose of translation reprint broadcast photomechanical or similar reproduction and storage or processing in computer systems in whole or in part are reserved No reproduction may occur without the express written consent from PHYTEC Messtechnik GmbH EUROPE NORTH AMERICA FRANCE Address PHYTEC Messtechnik GmbH PHYTEC America LLC PHYTEC France Robert Koch Str 39 203 Parfitt Way SW 17 place Saint Etienne D 55129 Mainz Bainbridge Island WA98110 F 72140 Sill le Guillaume GERMANY USA FRANCE Sales 49 6131 9221 32 1 800 278 9913 33 2 43 29 22 33 sales phytec de sales phytec com info phytec fr Technical 49 6131 9221 31 1 206 780 9047 Support support phytec de support phytec com support phytec fr Fax 49 6131 9221 33 1 206 780 9135 33 2 43 29 22 34 http www phytec de Web Site http www phytec eu http www phytec com http www phytec fr INDIA CHINA Address PHYTEC Embedded Pvt Ltd PHYTEC Information Technology Shenzhen Co Ltd 16 9C 3rd Main 3rd Floor 8th Block Suite 2611 Floor 26 Anlian Plaza Opp Police Station Koramangala 4018 Jin Tian Road Bangalore 560095 Futian District Shenzhen INDIA CHINA 518026 Sales 91 80 4086 7046 48 86 755 3395 5875 sales phytec in sales phytec cn Technical 91 80 4086 7047 Support support phytec in support phytec cn Fax 86 755 3395 5999 Web Site http www phytec in http www phytec cn 1 Edition August 2015
28. ou to avoid annoying problems Ap You can find useful supplementary information about the topic PHYTEC Messtechnik GmbH 2015 L 813e 1 11 Yocto Reference Manual PHYTEC Messtechnik GmbH 2015 L 813e 1 The Yocto Project 1 The Yocto Project 1 1 Introduction Yocto is the smallest SI metric system prefix Like m stands for milli 10 3 so is yocto y 10 24 Yocto is also a project working group of the Linux foundation and therefore backed up by several major companies in the field On the project website http www yoctoproject org you can read the official introduction The Yocto Project is an open source collaboration project that provides templates tools and methods to help you create custom Linux based systems for embedded products regardless of the hardware architecture It was founded in 2010 as a collaboration among many hardware manufacturers open source operating systems vendors and electronics companies to bring some order to the chaos of embedded Linux development As said the project wants to provide toolsets for embedded developers It builds on top of the long lasting OpenEmbedded project It is not a Linux distribution It contains the tools to create a Linux distribution specially fitted to the product requirements The most important step to bring order in the set of tools is to define a common versioning scheme and a reference system All subprojects have then to comply with the reference
29. ow be compressed with tar cf lt filename gt tar xz lt folder gt where filename and folder should be the full BSP name 6 7 3 Compiling on the Target To your local conf add IMAGE FEATURES append tools sdk dev pkgs 24 PHYTEC Messtechnik GmbH 2015 L 813e_1 Working with Poky and Bitbake 6 7 4 Different Toolchains There are several ways to create a toolchain installer in Poky First of all you can run bitbake meta toolchain This will generate a toolchain installer in build deploy sdk which can be used for cross compiling of target applications However the installer does not include libraries added to your image so it is a bare GCC compiler only This is suited for bootloader and kernel development Secondly you can run bitbake c pupulate_sdk lt your_image gt This will generate a toolchain installer containing all necessary development packages of the software installed on the rootfs of the target This installer can be handed over to the user space application development team and includes all necessary parts to develop an application If the image contains the Qt libraries all of those will be available in the installer too The third option would be to create the ADT Application Development Toolkit installer It will contain the cross toolchain and additionally some tools to aid the software developers e g an Eclipse plugin and a QEMU target simulator 6 7 5 Working with Kernel Modules You will c
30. r BSP 6 PHYTEC Messtechnik GmbH 2015 L 813e 1 Introduction to Phytec s BSP 3 1 2 4 meta phytec This layer contains common features for all our BSPs And is the core of our BSP together with the SOC layers Only those two parts are required if you want to integrate our BSP in your existing Yocto workflow 3 1 2 5 meta phytec meta phy lt SOC gt Those layers define the barebox kernel and software configuration for specific boards The boards get defined in the machine config files in conf machine 3 1 2 6 meta yogurt This is our example distribution It extends the basic configuration of Poky with software projects described by all the other BSP components It provides a base for some development scenarios A configuration for systemd is provided 3 2 Build Configuration The BSP initializes a build folder which will contain all files you create by running bitbake commands It contains a conf folder which handles build input variables e bblayers conf defines activated meta layers e local lonf defines build input variables specific to your build e site conf defines build input variables specific to the development host The two topmost build input variables are DISTRO and MACHINE they will be preconfigured in local conf when you check out the BSP using phyLinux In short DISTRO defines the software configuration MACHINE defines the hardware configuration As DISTRO we deliver yogurt with our BSP This distribution wi
31. r you can now modify the recipe with a bbappend without modifying any BSP code meta racer recipes images images phytec hwbringup image bbappend PHYTEC Messtechnik GmbH 2015 L 813e 1 17 Yocto Reference Manual The append will be parsed together with the base recipe e g in the new append you can override all variables set in the base recipe which is not always what you want If we want to include additional software we need to append to the IMAGE_INSTALL variable IMAGE_INSTALL_append rsync 6 6 4 Inspect Your Configuration Poky includes several tools to inspect your build layout You can inspect the commands of the layer tool bitbake layers It can for example be used to view in which layer a specific recipe gets modified bitbake layers show appends You should now see an entry for the phytec hwbringup image bb recipe which has an append in the meta racer layer You are now ready to create kernel patches and configurations and add them with appends in your layer 6 6 5 Kernel and Barebox Configuration and Patching Apart from using the standard versions of the Linux kernel and the barebox which are provided in the recipes you can modify the source code or use our own repositories to build your customized kernel The Yocto Project has already some documentation for software developers You should especially check the Kernel Development Manual for more information about how to configure the kernel e Yocto Kern
32. system and the versioning scheme The release process is similar to the Linux Kernel Yocto increases its version number every six month and gives the release a name The release list can be found here https wiki yoctoproject org wiki Releases 1 2 Core Components The most important tools or subprojects of the Yocto Project are e Bitbake build engine a task scheduler like make interprets metadata e OpenEmbedded Core a set of base layers containing metadata of software no sources e Yocto Kernel Optimized for embedded devices Includes many sub projects rt kernel vendor patches Infrastructure provided by Wind River Alternative classic kernel we use classic and not Yocto kernel e Yocto Reference BSP beagleboneblack minnow max e Poky the reference system a collection of projects and tools used to bootstrap a new distribution based on Yocto PHYTEC Messtechnik GmbH 2015 L 813e_1 1 Yocto Reference Manual 1 3 Vocabulary 1 3 1 Recipes Recipes contain information about the software project author homepage and license A Recipe is versioned defines dependencies contains the URL of the source code describes how to fetch configure and compile the sources It describes how to package the software e g into different deb packages which then contain the installation path Recipes are basically written in Bitbake s own programming language which has a simple syntax However a recipe can contain Pytho
33. t all your changes Otherwise yocto doesn t pick them up 2 Work and compile from the local working directory To work and compile in an external source directoy we provide the phyexternalsrc bbclass To use it copy and paste the following snippet to your local conf INHERIT phyexternalsrc EXTERNALSRC_pn barebox HOME git barebox PHYTEC Messtechnik GmbH 2015 L 813e 1 Yocto Reference Manual EXTERNALSRC_BUILD_pn barebox HOME git barebox Note All the compiling is done in the EXTERNALSRC directory Everytime you build an Image the package will be recompiled and build NOTE Tasks Summary Attempted 1 tasks of which 0 didn t need to be rerun and all succeeded NOTE Writing buildhistory As you can see everything is explained in the output Using phyexternalsrc or externalsrc breaks a lot of Yocto s internal dependency mechanism It s not guaranteed that any changes to the source directory is automatically picked up by the build process and incorporated into the root filesystem or SD card image You have to always use force E g to compile the barebox and redeploy it to deploy images lt machine gt execute bitbake barebox c compile force bitbake barebox c deploy To update the SD card image with a new kernel or image first force the compilation of it and then force a rebuild of the root filesystem Use bitbake phytec qt5demo image c rootfs force 6 6 Customizing the BSP
34. ually Repo will be automatically detected by phyLinux if it is found in the PATH The Repo tool will be used to manage the different Git repositories of the Yocto BSP 5 1 Get phyLinux The phyLinux script can be found on the PHYTEC ftp server 5 2 Basic Usage For the basic usage of phyLinux type usage phyLinux h v verbose init info clean This Programs sets up an environment to work with The Yocto Project on Phytecs Development Kits Use phyLinx lt command gt h to display the help text for the available commands positional arguments init info clean commands init init the phytec bsp in the current directory info print info about the phytec bsp in the current directory clean Clean up the current working directory optional arguments h help show this help message and exit v version show program s version number and exit verbose 10 PHYTEC Messtechnik GmbH 2015 L 813e_1 phyLinux Documentation 5 3 Initialization Create a fresh project folder e g and run phyLinux from the new folder A clean folder is important because phyLinux will clean its working directory So all files will be removed after the clean up Calling phyLinux not from an empty directory will result in the following warning This current directory is not empty It could lead to errors in the BSP configuration process if you continue from here At least you have to check your build directory for settings in bbla
35. working directory of the shell should change to build and you are now ready to build your first image We suggest to start with our hardware bring up image to see if everything is working correctly If you want you can separate the download process from the compile process to identify problems of your internet connection With bitbake c fetchall phytec hwbringup image all external source repositories get pulled into the download directory With du sh lt DL DIR gt you can see what the download volume was Now start the compile process bitbake phytec hwbringup image The first compile process takes about 40 minutes on a modern Intel Core 17 All subsequent builds will use the filled caches and should take about 3 minutes 6 2 Images If everything went fine the images can be found under cd deploy images lt MACHINE gt The easiest way to test your image is to jumper your board for booting from SD card and to flash the build image to the SD card sudo dd if phytec hwbringup image lt MACHINE gt sdcard of dev lt your_device gt bs 1MB Where lt your_device gt could be sde for example depending on your system Be very careful when selecting the right drive Selecting the wrong drive can erase your hard drive PHYTEC Messtechnik GmbH 2015 L 813e 1 13 Yocto Reference Manual After booting you can login using a serial cable or over ssh There is no root password That is because of the debug settings in co
36. yers conf and local conf which will not be handled correctly in all cases It is advisable to start from an empty directory of call phyLinux clean Do you really wantto continue from here yes no On the first initialization the phyLinux script will ask you to install the Repo tool in your usr local bin directory During the execution of the init command you need to choose your processor platform Phytec s BSP release number and the hardware you are working on e g kkxkxkkxkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Please choose one of the available Machines beagleboneblack 1 Hardware Revision A5C 2GiB eMMC phyboard maia am335x 1 PB 00702 002 phyboard wega am335x 1 PB 00802 0200C PB 00802 0101C PEB AV 01 phyboard wega am335x 2 PB 00802 008 PB 00802 010 PEB AV 02 phycore am335x 1 PCM 051 12102F0C A1 KPCM 953 Kit phycore am335x 2 1GiB RAM 1GiB NAND variant phyflex am335x 1 PFL A 03 12113F8I A1 PBA B 01 If you cannot identify your board with the information given in the selector have a look at the invoice of the product After the configuration is done you can always run or view the help command for more information PHYTEC Messtechnik GmbH 2015 L 813e_1 11 Yocto Reference Manual usage phyLinux init h verbose no init o REPOREPO x XML u URL p PLATFORM r RELEASE optional arguments h help show this help message and exit verbose no init dont
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