Commit graph

6 commits

Author SHA1 Message Date
Simon Glass
7839865272 bootm: Tidy up use of autostart env var
This has different semantics in different places. Go with the bootm method
and put it in a common function so that the behaviour is consistent in
U-Boot. Update the docs.

To be clear, this changes the way that 'bootelf' and standalone boot
work. Before, if autostart was set to "fred" or "YES", for example, they
would consider that a "yes". This may change behaviour for some boards,
but the only in-tree boards which mention autostart use "no" to disable
it, which will still work.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Wolfgang Denk <wd@denx.de>
2021-11-16 14:35:09 -05:00
Simon Glass
40b9e0dd05 doc: Improve environment documentation further
Make various other updates suggested during review of the rST conversion.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2021-11-16 14:35:08 -05:00
Simon Glass
5ba9e01a3e doc: Improve environment documentation
Make various updates suggested during review of the rST conversion.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Suggested-by: Wolfgang Denk <wd@denx.de>
2021-11-16 14:35:08 -05:00
Simon Glass
1df02d1d01 doc: Mention CONFIG_DEFAULT_ENV_FILE
Add mention of this option since it does a similar thing to the text
environment.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
2021-11-16 14:35:08 -05:00
Simon Glass
86b9c3e4e4 env: Allow U-Boot scripts to be placed in a .env file
At present U-Boot environment variables, and thus scripts, are defined
by CONFIG_EXTRA_ENV_SETTINGS. It is painful to add large amounts of text
to this 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.

Add a feature that brings in a .env file associated with the board
config, if present. To use it, create a file in a board/<vendor>
directory, typically called <board>.env and controlled by the
CONFIG_ENV_SOURCE_FILE option.

The environment variables should be of the form "var=value". Values can
extend to multiple lines. See the README under 'Environment Variables:'
for more information and an example.

In many cases environment variables need access to the U-Boot CONFIG
variables to select different options. Enable this so that the environment
scripts can be as useful as the ones currently in the board config files.
This uses the C preprocessor, means that comments can be included in the
environment using /* ... */

Also support += to allow variables to be appended to. This is needed when
using the preprocessor.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Tested-by: Marek Behún <marek.behun@nic.cz>
2021-11-16 14:35:08 -05:00
Simon Glass
ea754aa565 doc: Move environment documentation to rST
Move this from the README to rST format.

Drop i2cfast since it is obviously obsolete and breaks the formatting.
Other changes and improvements are in a following patch.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Marek Behún <marek.behun@nic.cz>
2021-11-16 14:35:08 -05:00