u-boot/CLAUDE.md

U-Boot Build Instructions for Claude Code

This file contains information about building U-Boot for use with Claude Code.

Building U-Boot

Using uman (Recommended)

To build U-Boot for sandbox testing, use the um command:

# Build for sandbox without LTO (um is a symlink to uman)
um build sandbox [flags]

# The -l flag can be used to enable LTO
# The build is silent unless there are warnings or errors
# The build is done in /tmp/b/<board_name>, so /tmp/b/sandbox in this case

Using make directly

If you prefer to use make directly, please use O= to avoid adding build files to the source tree:

# Clean the build (recommended before first build)
make mrproper

# Configure for sandbox
make sandbox_defconfig O=/tmp/<build_dir>

# Build
make -j$(nproc) O=/tmp/<build_dir>

Testing

There are aliases in ~/bin/git-alias which you can use.

To run a sandbox test:

um test <test_name>
# For example: rtv dm_test_video_box
# similar to: /tmp/b/sandbox/u-boot -v -Tf -c "ut dm video_box"
# test output is silenced unless -v is given

To run using the Python suite:

um py -B sandbox <test_name>
# similar to: test/py/test.py -B sandbox --build-dir /tmp/b/sandbox -k <test_name>

Notes

• The um tool is the preferred build method for this codebase
• Always run make mrproper if you encounter build issues
• The sandbox build creates a test environment for U-Boot that runs on the host system
• When using git diff, add --no-ext-diff to avoid external diff tools that may not work in this environment
• um build shows no output if everything was ok!
• Remember not to cd into the build directory; run U-Boot directly in the source dir
• Do not run in-tree builds; always use the crosfw script or 'make O=/tmp/...'

Coding Conventions

• For function parameters that return values (output parameters), add 'p' suffix to indicate pointer
  • Example: uint *sizep instead of uint *size
  • Example: bool *visiblep instead of bool *visible
• This follows U-Boot's established naming convention for output parameters
• Keep commit messages concise - focus on the key change and essential details only
• Code should be formatted to 80 columns and not have trailing spaces
• Remember to use Co-developed-by instead of Co-Authored-By in commits
• Test declarations (e.g., UNIT_TEST macro) should immediately follow the closing } of the function they declare, with no blank line in between