On Tue, Oct 19, 2021 at 04:44:15PM -0600, Simon Glass wrote: > One barrier to completing the 7-year-long Kconfig migration is that > the default environment is implemented using ad-hoc CONFIG options. > At present U-Boot environment variables, and thus scripts, are defined > by CONFIG_EXTRA_ENV_SETTINGS. > > It is not really feasible to move the environment to Kconfig as it is > hundreds of lines of text in some cases. > > Even considering the current situation, it is painful to add large > amounts of text to the config-header file and dealing with quoting and > newlines is harder than it should be. It would be better if we could just > type the script into a text file and have it included by U-Boot. > > This is already supported by the CONFIG_USE_DEFAULT_ENV_FILE feature. but > that does not support use of CONFIG options or comments, so is best suited > for use by other build systems wanting to define the U-Boot environment. > > Add a feature that brings in a .env file associated with the board > config, if present. To use it, create a file board/<vendor>/<board>.env or > use CONFIG_ENV_SOURCE_FILE to set a filename. > > The environment variables should be of the form "var=value". Values can > extend to multiple lines. This series converts the existing environment > documentation to rST and updates it to explain how to use this. > > Note: this series was originally sent eight years ago: > > https://patchwork.ozlabs.org/project/uboot/patch/1382763695-2849-4-git-send-email-...@chromium.org/ > > It has been updated to work with Kconfig, etc. Some review comments in > that patch were infeasible so I have not addressed them. I would like > this series to be considered independently, on its merits. > > Rather than deal with the complexity of rewriting the distro-boot > script, this is disabled for sandbox. The forthcoming bootmethod approach > should provide the same functionality without needing the complex > scripting in the environment. > > Migration needs more thought, although it can be done later. It may be > possible to do migrate automatically, using buildman to extract the > built-in environmnent from the ELF file. > > This would produce a pretty ugly conversion though, since it would drop > all the intermediate variables used to create the environment. > > Better would be to parse the config.h file, figure out the components of > CONFIG_EXTRA_ENV_SETTINGS then output these as separate pieces in the > file. It is not clear how easy that would be, nor whether the result would > be very pretty. Also the __stringify() macro needs to be handled somehow. > > This series is available at u-boot-dm/env-working > > Comments welcome. > > Changes in v9: > - Drop mention of other strange characters > - Clarify that the + restriction is on the variable name not its value > - Add some tests for the script > - Deal with leading tabs > - Squash indentation down to one space > - Convert newlines within strings to spaces, which seems more consistent > - Handle appending an empty string to an empty var > - Fix blank line between tags > - Fix typo in commit message > - More bikeshedding on env_get_autostart() > - Fix '<vendor><board>' in cover letter > - Use env_get_yesno() in env_get_autostart() and update docs > > Changes in v8: > - Update commit message to avoid mentioning the 'env' subdirectory > - Update commit message to mention the + restriction, etc. > - Overwrite the env file each time, to avoid incremental-build problems > - Fix ambiguity about what is ignored > - Go into more detail about the change of behaviour with autostart > > Changes in v7: > - Use 'env' basename instead of 'environment' for intermediate output files > - Show a message indicating the source text file being used > - Give an error if CONFIG_EXTRA_ENV_SETTINGS is also defined > - Use CONFIG_ENV_SOURCE_FILE instead of rules to specify the text-file name > - Make board.env the default name if CONFIG_ENV_SOURCE_FILE is empty > - Rewrite the documentation > - Drop the use of common.env > - Update awk script to output the whole CONFIG string, or just a comment > - Add new patch to explain the relationship with DEFAULT_ENV_FILE > - A few more tweaks > - Update the cover letter > > Changes in v6: > - Move all updates to a separate patch > - Combine the two env2string.awk patches into one > - Move all updates to a separate patch > - More updates and improvements > - Add new patch to tidy up use of autostart env var > > Changes in v5: > - Minor updates as suggested by Wolfgang > - Explain how to include the common.env file > - Explain why variables starting with _ , and / are not supported > - Expand the definition of how to declare an environment variable > - Explain what happens to empty variables > - Update maintainer > - Move use of += to this patch > - Explain that environment variables may not end in + > - Minor updates as suggested by Wolfgang > > Changes in v4: > - Add new patch to move environment documentation to rST > - Move this from being part of configuring U-Boot to part of building it > - Don't put the environment in autoconf.mk as it is not needed > - Add documentation in rST format instead of README > - Drop mention of import/export > - Update awk script to ignore blank lines, as generated by clang > - Add documentation in rST format instead of README > - Add new patch to move environment documentation to rST > > Changes in v3: > - Adjust Makefile to generate the .inc and .h files in separate fules > - Add more detail in the README about the format of .env files > - Improve the comment about " in the awk script > - Correctly terminate environment files with \n > - Define __UBOOT_CONFIG__ when collecting environment files > - Add new patch to use a text-based environment for sandbox > > Changes in v2: > - Move .env file from include/configs to board/ > - Use awk script to process environment since it is much easier on the brain > - Add information and updated example script to README > - Add dependency rule so that the environment is rebuilt when it changes > - Add separate patch to enable C preprocessor for environment files > - Enable var+=value form to simplify composing variables in multiple steps > > Simon Glass (7): > sandbox: Drop distro_boot > doc: Move environment documentation to rST > env: Allow U-Boot scripts to be placed in a .env file > sandbox: Use a text-based environment > doc: Mention CONFIG_DEFAULT_ENV_FILE > doc: Improve environment documentation > bootm: Tidy up use of autostart env var > > MAINTAINERS | 7 + > Makefile | 66 ++++- > README | 328 ------------------------- > board/sandbox/sandbox.env | 25 ++ > cmd/bootm.c | 4 +- > cmd/elf.c | 3 +- > common/bootm_os.c | 5 +- > config.mk | 2 + > doc/usage/environment.rst | 490 ++++++++++++++++++++++++++++++++++++++ > doc/usage/index.rst | 1 + > env/Kconfig | 18 ++ > env/common.c | 5 + > env/embedded.c | 1 + > include/configs/sandbox.h | 40 ---- > include/env.h | 7 + > include/env_default.h | 11 + > scripts/env2string.awk | 71 ++++++ > test/py/tests/test_env.py | 93 ++++++++ > 18 files changed, 799 insertions(+), 378 deletions(-) > create mode 100644 board/sandbox/sandbox.env > create mode 100644 doc/usage/environment.rst > create mode 100644 scripts/env2string.awk
Cc'ing the other lists... -- Tom
signature.asc
Description: PGP signature
