On Tue, Oct 17, 2023 at 10:14:13AM +0200, Wojciech Niziński wrote:
Hello.
Very nice feature was introduced in commit:
86b9c3e4e48ba47ef28781d06b97846aca74bc8e| env: Allow U-Boot scripts to be placed in a .env file
This feature works as extension for old CFG_EXTRA_ENV_SETTINGS and make me confused why it doesn't work for configured default env file.
Now in U-Boot config we have two features related to external environment file:
1st feature (introduced by mentioned commit):
CONFIG_ENV_SOURCE_FILE "Environment file to use"
2nd feature
CONFIG_USE_DEFAULT_ENV_FILE "Create default environment from file"
CONFIG_DEFAULT_ENV_FILE "Path to default environment file"
In 1st feature only basename of .env file can be specified. So env file can be located only in board dir which is a limitation for this nice feature:
"The file must be in the board directory and have a .env extension, so the resulting filename is typically board/<vendor>/<board>/<CONFIG_ENV_SOURCE_FILE>.env"
In 2nd feature I can specify default env file as full path so it can be located everywhere - even outside U-Boot source - which is very nice when U-Boot is built by Buildroot. I can easily set path as system environment variable and it works:
CONFIG_USE_DEFAULT_ENV_FILE=y CONFIG_DEFAULT_ENV_FILE="$(BR2_EXTERNAL_FOO_PATH)/board/foo/u-boot.env"
Unfortunately I cannot do the same for 1st feature without patching U-Boot sources to put my custom env file into board dir.
I can see two way of improving features: 1st: to extend 1st feature with ability to specify full patch to env file, or 2nd one: run the same parsing mechanism also for 2nd feature (default env file).
Your analysis of how things work is correct. The intention is that, as you noted, is that the plain text environment and CONFIG_ENV_SOURCE_FILE replace the older default environment found in include/env_default.h and often augmented by the board.h file via (formerly CONFIG now CFG) EXTRA_ENV_SETTINGS and CONFIG_USE_DEFAULT_ENV_FILE to be the complete replacement of the environment option. So I think the next reasonable step would be to be able to have plain text environment style files work for CONFIG_USE_DEFAULT_ENV_FILE which I think you're saying doesn't today. But I think that yes, a patch to parse the new-style plain text files for CONFIG_USE_DEFAULT_ENV_FILE would be good, and I suspect buildroot has enough users of that feature that any corner cases with trying to parse older files could be caught and fixed?