Mark DISTRO_DEFAULTS as deprecated
Standard boot has been in place for a while now. Quite a few problems
have been found and fixed. It seems like a good time to mark the
script-based approach as deprecated and encourage people to use standard
boot.
Update the DISTRO_DEFAULTS Kconfig to encourage people to move to
standard boot, which is able to boot Linux distributions automatically.
Add a short migration guide to make this easier.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/boot/Kconfig b/boot/Kconfig
index 4ebcf31..7ef44a2 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -784,7 +784,7 @@
endmenu # Boot images
config DISTRO_DEFAULTS
- bool "Select defaults suitable for booting general purpose Linux distributions"
+ bool "(deprecated) Script-based booting of Linux distributions"
select BOOT_DEFAULTS
select AUTO_COMPLETE
select CMDLINE_EDITING
@@ -792,6 +792,10 @@
select HUSH_PARSER
select SYS_LONGHELP
help
+ Note: These scripts have been replaced by Standard Boot. Do not use
+ them on new boards. See 'Migrating from distro_boot' at
+ doc/develop/bootstd.rst
+
Select this to enable various options and commands which are suitable
for building u-boot for booting general purpose Linux distributions.
diff --git a/doc/develop/bootstd.rst b/doc/develop/bootstd.rst
index e8b9075..6172dc9 100644
--- a/doc/develop/bootstd.rst
+++ b/doc/develop/bootstd.rst
@@ -464,6 +464,28 @@
======= =======================================================================
+Migrating from distro_boot
+--------------------------
+
+To migrate from distro_boot:
+
+#. Update your board header files to remove the BOOTENV and BOOT_TARGET_xxx
+ defines. Standard boot finds available boot devices automatically.
+
+#. Remove the "boot_targets" variable unless you need it. Standard boot uses a
+ default order from fastest to slowest, which generally matches the order used
+ by boards.
+
+#. Make sure that CONFIG_BOOTSTD_DEFAULTS is enabled by your board, so it can
+ boot common Linux distributions.
+
+An example patch is at migrate_patch_.
+
+If you are using custom boot scripts for your board, consider creating your
+own bootmeth to hold the logic. There are various examples at
+`boot/bootmeth_...`.
+
+
Theory of operation
-------------------
@@ -775,3 +797,4 @@
.. _BootLoaderSpec: http://www.freedesktop.org/wiki/Specifications/BootLoaderSpec/
.. _distro_boot: https://github.com/u-boot/u-boot/blob/master/boot/distro.c
.. _bootflow_h: https://github.com/u-boot/u-boot/blob/master/include/bootflow.h
+.. _migrate_patch: https://patchwork.ozlabs.org/project/uboot/patch/20230727215433.578830-2-sjg@chromium.org/