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 --- env/Kconfig | 18 ++++++++++++++++++ env/common.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+) (limited to 'env') diff --git a/env/Kconfig b/env/Kconfig index 1b7906c..1411f9e 100644 --- a/env/Kconfig +++ b/env/Kconfig @@ -670,6 +670,24 @@ config DELAY_ENVIRONMENT later by U-Boot code. With CONFIG_OF_CONTROL this is instead controlled by the value of /config/load-environment. +config ENV_IMPORT_FDT + bool "Amend environment by FDT properties" + depends on OF_CONTROL + help + If selected, after the environment has been loaded from its + persistent location, the "env_fdt_path" variable is looked + up and used as a path to a node in the control DTB. The + property/value pairs in that node is then used to update the + run-time environment. This can be useful to use the same + U-Boot binary with different board variants. + +config ENV_FDT_PATH + string "Default value for env_fdt_path variable" + depends on ENV_IMPORT_FDT + default "/config/environment" + help + The initial value of the env_fdt_path variable. + config ENV_APPEND bool "Always append the environment with new data" default n diff --git a/env/common.c b/env/common.c index 49bbb05..81e9e0b 100644 --- a/env/common.c +++ b/env/common.c @@ -20,6 +20,7 @@ #include #include #include +#include DECLARE_GLOBAL_DATA_PTR; @@ -334,3 +335,32 @@ int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf, return found; } #endif + +#ifdef CONFIG_ENV_IMPORT_FDT +void env_import_fdt(void) +{ + const char *path; + struct ofprop prop; + ofnode node; + int res; + + path = env_get("env_fdt_path"); + if (!path || !path[0]) + return; + + node = ofnode_path(path); + if (!ofnode_valid(node)) { + printf("Warning: device tree node '%s' not found\n", path); + return; + } + + for (res = ofnode_get_first_property(node, &prop); + !res; + res = ofnode_get_next_property(&prop)) { + const char *name, *val; + + val = ofnode_get_property_by_prop(&prop, &name, NULL); + env_set(name, val); + } +} +#endif -- cgit v1.1