Scott Rifenbark, Intel Corporation <[email protected]> by Scott Rifenbark Copyright © 2010-2014 Linux Foundation Permission is granted to copy, distribute and/or modify this document under the terms of the Creative Commons Attribution-Share Alike 2.0 UK: England & Wales [http://creativecommons.org/licenses/by-sa/2.0/uk/] as published by Creative Commons. Note For the latest version of this manual associated with this Yocto Project release, see the Yocto Project Development Manual [http://www.yoctoproject.org/docs/1.7/dev-manual/dev-manual.html] from the Yocto Project website. Table of Contents 1. The Yocto Project Development Manual .................................................................................. 1 1.1. Introduction ................................................................................................................. 1 1.2. What This Manual Provides .......................................................................................... 1 1.3. What this Manual Does Not Provide ............................................................................. 1 1.4. Other Information ........................................................................................................ 2 2. Getting Started with the Yocto Project .................................................................................... 4 2.1. Introducing the Yocto Project ....................................................................................... 4 2.2. Getting Set Up ............................................................................................................ 4 2.3. Building Images ........................................................................................................... 7 2.4. Using Pre-Built Binaries and QEMU ............................................................................... 7 3. The Yocto Project Open Source Development Environment ...................................................... 9 3.1. Open Source Philosophy .............................................................................................. 9 3.2. Using the Yocto Project in a Team Environment ............................................................ 9 3.2.1. System Configurations ...................................................................................... 9 3.2.2. Source Control Management (SCM) ................................................................. 10 3.2.3. Autobuilders ................................................................................................... 11 3.2.4. Policies and Change Flow ................................................................................ 11 3.2.5. Summary ........................................................................................................ 12 3.3. Yocto Project Source Repositories ............................................................................... 12 3.4. Yocto Project Terms .................................................................................................... 14 3.5. Licensing ................................................................................................................... 17 3.6. Git ............................................................................................................................. 18 3.6.1. Repositories, Tags, and Branches .................................................................... 18 3.6.2. Basic Commands ............................................................................................ 19 3.7. Workflows .................................................................................................................. 20 3.8. Tracking Bugs ............................................................................................................ 22 3.9. How to Submit a Change ........................................................................................... 23 3.9.1. Using Scripts to Push a Change Upstream and Request a Pull ........................... 25 3.9.2. Using Email to Submit a Patch ........................................................................ 25 4. Common Development Models ............................................................................................. 27 4.1. System Development Workflow .................................................................................. 27 4.1.1. Developing a Board Support Package (BSP) ..................................................... 27 4.1.2. Modifying the Kernel ....................................................................................... 30 4.2. Application Development Workflow ............................................................................ 34 4.2.1. Workflow Using the ADT and Eclipse™ ............................................................ 34 4.2.2. Working Within Eclipse .................................................................................... 37 4.2.3. Workflow Using Stand-Alone Cross-Development Toolchains ............................. 45 4.3. Modifying Temporary Source Code ............................................................................. 46 4.3.1. Finding the Temporary Source Code ................................................................ 46 4.3.2. Using a Quilt Workflow .................................................................................... 47 4.3.3. Using a Git Workflow ...................................................................................... 48 4.4. Image Development Using Hob .................................................................................. 50 4.5. Using a Development Shell ........................................................................................ 50 5. Common Tasks ..................................................................................................................... 52 5.1. Understanding and Creating Layers ........................................................................... 52 5.1.1. Layers ............................................................................................................ 52 5.1.2. Creating Your Own Layer ................................................................................ 52 5.1.3. Best Practices to Follow When Creating Layers ................................................ 54 5.1.4. Enabling Your Layer ........................................................................................ 55 5.1.5. Using .bbappend Files ..................................................................................... 56 5.1.6. Prioritizing Your Layer ..................................................................................... 57 5.1.7. Managing Layers ............................................................................................ 58 5.1.8. Creating a General Layer Using the yocto-layer Script ..................................... 59 5.2. Customizing Images .................................................................................................. 60 5.2.1. Customizing Images Using local.conf ........................................................... 60 5.2.2. Customizing Images Using Custom IMAGE_FEATURES and EXTRA_IMAGE_FEATURES ............................................................................................ 61 5.2.3. Customizing Images Using Custom .bb Files .................................................... 61 5.2.4. Customizing Images Using Custom Package Groups ......................................... 62 5.3. Writing a New Recipe ................................................................................................ 62 5.3.1. Overview ........................................................................................................ 63 iii Yocto Project Development Manual 5.3.2. Locate a Base Recipe ..................................................................................... 63 5.3.3. Storing and Naming the Recipe ....................................................................... 64 5.3.4. Understanding Recipe Syntax .......................................................................... 65 5.3.5. Running a Build on the Recipe ........................................................................ 68 5.3.6. Fetching Code ................................................................................................. 69 5.3.7. Unpacking Code .............................................................................................. 70 5.3.8. Patching Code ................................................................................................ 71 5.3.9. Licensing ........................................................................................................ 71 5.3.10. Configuring the Recipe .................................................................................. 72 5.3.11. Compilation .................................................................................................. 73 5.3.12. Installing ....................................................................................................... 73 5.3.13. Enabling System Services ............................................................................. 74 5.3.14. Packaging ..................................................................................................... 75 5.3.15. Properly Versioning Pre-Release Recipes ........................................................ 76 5.3.16. Post-Installation Scripts ................................................................................