From 95fd9772011f29fad2c40fbc3060b5dac042152c Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 21 Apr 2021 11:06:54 +0200 Subject: env: allow environment to be amended from control dtb It can be useful to use the same U-Boot binary for multiple purposes, say the normal one, one for developers that allow breaking into the U-Boot shell, and one for use during bootstrapping which runs a special-purpose bootcmd. Or one can have several board variants that can share almost all boot logic, but just needs a few tweaks in the variables used by the boot script. To that end, allow the control dtb to contain a /config/enviroment node (or whatever one puts in fdt_env_path variable), whose property/value pairs are used to update the run-time environment after it has been loaded from its persistent location. The indirection via fdt_env_path is for maximum flexibility - for example, should the user wish (or board logic dictate) that the values in the DTB should no longer be applied, one simply needs to delete the fdt_env_path variable; that can even be done automatically by including a fdt_env_path = ""; property in the DTB node. Reviewed-by: Simon Glass Signed-off-by: Rasmus Villemoes Acked-by: Joe Hershberger --- include/env.h | 15 +++++++++++++++ include/env_default.h | 3 +++ 2 files changed, 18 insertions(+) (limited to 'include') diff --git a/include/env.h b/include/env.h index b5731e4b9a..d5e2bcb530 100644 --- a/include/env.h +++ b/include/env.h @@ -375,4 +375,19 @@ int env_get_char(int index); * This is used for those unfortunate archs with crappy toolchains */ void env_reloc(void); + + +/** + * env_import_fdt() - Import environment values from device tree blob + * + * This uses the value of the environment variable "env_fdt_path" as a + * path to an fdt node, whose property/value pairs are added to the + * environment. + */ +#ifdef CONFIG_ENV_IMPORT_FDT +void env_import_fdt(void); +#else +static inline void env_import_fdt(void) {} +#endif + #endif diff --git a/include/env_default.h b/include/env_default.h index ea31a8eddf..1ddd64ba8f 100644 --- a/include/env_default.h +++ b/include/env_default.h @@ -103,6 +103,9 @@ const uchar default_environment[] = { #ifdef CONFIG_SYS_SOC "soc=" CONFIG_SYS_SOC "\0" #endif +#ifdef CONFIG_ENV_IMPORT_FDT + "env_fdt_path=" CONFIG_ENV_FDT_PATH "\0" +#endif #endif #if defined(CONFIG_BOOTCOUNT_BOOTLIMIT) && (CONFIG_BOOTCOUNT_BOOTLIMIT > 0) "bootlimit=" __stringify(CONFIG_BOOTCOUNT_BOOTLIMIT)"\0" -- cgit