U-boot Source Code Clean Up Project and How-to Recruiting Volunteers! Macpaul Lin (2012/08/18)
Outline• Why do we do clean up?• Who should join the clean up project? And How will you be benefited with it?• How to do the clean up work?• Summary.
Why do we do clean up?• U-boot is old. – It is an old boot loader project and widely be used in various embedded systems. – There are many dirty historical codes. Linux has them, too.• Coding style are mixed. – It supports booting OS from various different devices which leverage codes from various open source projects. Such as dlmalloc, Linux, and etc.
Why do we do clean up?• Developers usually get confused. – Some coding style really introduce problem when doing debugging. – New contributor usually get confused between old and new coding style. • This usually lead unnecessary time cost when developers reviewing and fixing their patches.
Why do we do clean up?• It follows Linux coding style.• However, since u-boot has long history just like Linux kernel, source codes some were dirty and need to be clean up.• New comers and new contributors usually reference the old coding style. Hence the patch is usually need to be reworked and viewers spent lots of effort on replying mail.
Who should join the clean up project and how will you be benefits with it?• U-boot uses git and mailing list to management the source code developing. – Student who wants to be familiar with git source version control. – Student who wants to join a open source project and practice with patch commitment mailing discussion. – People who is interested in boot loader with embedded device development environments.
How to do the clean up work?• U-boot project uses the checkpatch.pl in Linux kernel to check the patches.• Clean up patches must obey both Linux coding style and u-boot coding style.• Coding style – http://www.denx.de/wiki/U-Boot/CodingStyle• Patch rules – http://www.denx.de/wiki/U-Boot/Patches
Steps to join u-boot project1. Sign-up the mailing list2. Clone the source code3. Use checkpatch.pl to check the oldcodes.4. Fix warnings reported by checkpatch.pl5. Use git send-email to commit thecleanup back to mailing list.6. Fix your patch if maintainer give yousuggestion to fix.
1. Sign-up the mailing list• Subscribe http://lists.denx.de/mailman/listinfo/u-boot Dont choose "yes" because maintainers will reply your patch by mail.
2. Clone the source code• Clone the source code – git clone git://git.denx.de/u-boot.git u-boot.git• Setting git users and email – git config --global user.name "yourname"; – git config --global user.email "you@youremail";• Make a working branch – cd u-boot.git – git branch cleanup• Checkout the working branch and getting start – git checkout cleanup
3. Use checkpatch.pl to check the old codes.• Once you finish a patch, use tools/checkpatch.pl to verify the patch is clean before send it out.• So we can use this checkpatch.pl to check if the current files are clean.• Most of the old code is inside “common folder".
3. Use checkpatch.pl to check the old codes.• 3.0 Export the path of checkpatch.pl into $PATH – export PATH=$PATH:~/u-boot.git/tools
3. Use checkpatch.pl to check the old codes.• 3.1 find a unclean file in folder “common” – For example: "bedbug.c" – cd common• 3.2 copy it as a backup – cp bedbug.c bedbug.c.bak
3. Use checkpatch.pl to check the old codes.• 3.3 remove “bedbug.c” as commit A because we will check the whole file later – git rm bedbug.c – git commit -s • Input some reason because this is just a temporary work.
3. Use checkpatch.pl to check the old codes.• 3.4 now we recover the unclean file and make this as a commit B. – mv bedbug.c.bak bedbug.c – git add bedbug.c – git commit -s • Input the real commit log.
4. Fix warnings reported by checkpatch.pl• 4.1 Create a folder for this commit B – mkdir patch – cd patch• 4.2 Export this commit B (the latest commit) and use checkpatch.pl to get the report. – git format-patch HEAD~1 – checkpatch 0001-cosmetic-add-bedbug.c- back.patch
4. Fix warnings reported by checkpatch.pl• 4.3 You will get the report from checkpatch.
4. Fix warnings reported by checkpatch.pl• 4.4 Now you can fix all the error of bedbug.c with your favorite editor based on this report. – cd .. (back to “common" folder) – vim bedbug.c – (you can also use “git diff” to check your changes)
4. Fix warnings reported by checkpatch.pl• 4.5 Create a clean commit "C" as the result of your work. – git add debug.c – git commit -s
4. Fix warnings reported by checkpatch.pl• 4.6 Now you have 3 commits “A,B,C” in "cleanup" branch
4. Fix warnings reported by checkpatch.pl• 4.7 We only need the last commit "C" to send back to mailing list. – Remove commit "B" in patch folder • rm patch/0001-cosmetic-add-bedbug.c-back.patch – Export the final patch commit "C" • cd patch • git format-patch HEAD~1 – Use checkpatch.pl to check it again. • checkpatch 0001-cosmetic-clean-up-common- bedbug.c-by-checkpatch.pl.patch
5. Use git send-email to commit the cleanup back to mailing list.• 5.1 Finally send the patch out. – git send-email 0001-cosmetic-clean-up- common-bedbug.c-by-checkpatch.pl.patch – Remember add maintainers to “To:” list to review the patch.
6. Fix your patch if maintainer give you suggestion to fix.• After a maintainer reviewed your patch, he will reply your mail to inform you if the patch has been accepted or the patch is still need to be fixed.
Summary• There are many old-style codes need to be cleaned up. We need your help.• Please join u-boot project. – Just subscribe http://lists.denx.de/mailman/listinfo/u-boot