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authorSimon Glass <sjg@chromium.org>2021-10-21 21:08:48 -0600
committerTom Rini <trini@konsulko.com>2021-11-16 14:35:08 -0500
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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 BehĂșn <marek.behun@nic.cz>
Diffstat (limited to 'doc')
-rw-r--r--doc/usage/environment.rst15
1 files changed, 15 insertions, 0 deletions
diff --git a/doc/usage/environment.rst b/doc/usage/environment.rst
index 043c02d..6f3066e 100644
--- a/doc/usage/environment.rst
+++ b/doc/usage/environment.rst
@@ -458,3 +458,18 @@ The signature of the callback functions is::
include/search.h
The return value is 0 if the variable change is accepted and 1 otherwise.
+
+
+External environment file
+-------------------------
+
+The `CONFIG_USE_DEFAULT_ENV_FILE` option provides a way to bypass the
+environment generation in U-Boot. If enabled, then `CONFIG_DEFAULT_ENV_FILE`
+provides the name of a file which is converted into the environment,
+completely bypassing the standard environment variables in `env_default.h`.
+
+The format is the same as accepted by the mkenvimage tool, with lines containing
+key=value pairs. Blank lines and lines beginning with # are ignored.
+
+Future work may unify this feature with the text-based environment, perhaps
+moving the contents of `env_default.h` to a text file.