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. To that end, allow the control dtb to contain
a /config/default-enviroment property, whose value will be used to
amend the default environment baked into the U-Boot binary itself.
Signed-off-by: Rasmus Villemoes <rasmus.villem...@prevas.dk>
---
cmd/nvedit.c | 37 +++++++++++++++++++++++++++++++++++++
env/Kconfig | 21 +++++++++++++++++++++
env/common.c | 19 +++++++++++++++++++
3 files changed, 77 insertions(+)
diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index 7fce723800..eda8b3b9d2 100644
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -703,6 +703,39 @@ char *from_env(const char *envvar)
return ret;
}
+static int env_get_f_fdt(const char *name, char *buf, unsigned len)
+{
+ const char *env;
+ int plen, nlen, n;
+
+ if (!IS_ENABLED(CONFIG_ENV_AMEND_DEFAULT_FROM_FDT))
+ return 0;
+
+ env = fdtdec_get_config_property(gd->fdt_blob, "default-environment",
+ &plen);
+ if (!env)
+ return 0;
+
+ nlen = strlen(name);
+ while (plen > nlen) {
+ if (memcmp(name, env, nlen) == 0 && env[nlen] == '=') {
+ /* Found. Copy value. */
+ n = strlcpy(buf, &env[nlen + 1], len);
+ if (n < len)
+ return n;
+
+ printf("env_buf [%u bytes] too small for value of
\"%s\"\n",
+ len, name);
+ return len;
+ }
+ /* Skip this key=val pair. */
+ n = strlen(env) + 1;
+ plen -= n;
+ env += n;
+ }
+ return 0;
+}
+
/*
* Look up variable from environment for restricted C runtime env.
*/
@@ -710,6 +743,10 @@ int env_get_f(const char *name, char *buf, unsigned len)
{
int i, nxt, c;
+ i = env_get_f_fdt(name, buf, len);
+ if (i)
+ return i;
+
for (i = 0; env_get_char(i) != '\0'; i = nxt + 1) {
int val, n;
diff --git a/env/Kconfig b/env/Kconfig
index 67ce93061b..66bbac42c7 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -646,6 +646,27 @@ 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_AMEND_DEFAULT_FROM_FDT
+ bool "Amend default environment by /config/default-environment property"
+ depends on OF_CONTROL
+ help
+ The default environment built into the U-Boot binary is a
+ static array defined from various CONFIG_ options, or via
+ CONFIG_DEFAULT_ENV_FILE. Selecting this option means that
+ whenever that default environment is used (either for
+ populating the initial environment, or for resetting
+ specific variables to their default value), the device tree
+ property /config/default-environment is also consulted, and
+ values found there have precedence over those in the static
+ array. That property should be a series of "key=value"
+ pairs, e.g.
+
+ /config {
+ default-environment = "ipaddr=1.2.3.4",
+ "bootcmd=tftp $loadaddr foo.itb; bootm
$loadaddr",
+ "bootdelay=5";
+ }
+
config ENV_APPEND
bool "Always append the environment with new data"
default n
diff --git a/env/common.c b/env/common.c
index 7363da849b..8d0e45fde6 100644
--- a/env/common.c
+++ b/env/common.c
@@ -63,6 +63,22 @@ char *env_get_default(const char *name)
return ret_val;
}
+static void env_amend_default_from_fdt(int flags, int nvars, char *const
vars[])
+{
+ const void *val;
+ int len;
+
+ if (!IS_ENABLED(CONFIG_ENV_AMEND_DEFAULT_FROM_FDT))
+ return;
+
+ val = fdtdec_get_config_property(gd->fdt_blob, "default-environment",
+ &len);
+ if (!val)
+ return;
+
+ himport_r(&env_htab, val, len, '\0', flags, 0, nvars, vars);
+}
+
void env_set_default(const char *s, int flags)
{
if (sizeof(default_environment) > ENV_SIZE) {
@@ -88,6 +104,8 @@ void env_set_default(const char *s, int flags)
pr_err("## Error: Environment import failed: errno = %d\n",
errno);
+ env_amend_default_from_fdt(flags | H_NOCLEAR, 0, NULL);
+
gd->flags |= GD_FLG_ENV_READY;
gd->flags |= GD_FLG_ENV_DEFAULT;
}
@@ -104,6 +122,7 @@ void env_set_default_vars(int nvars, char * const vars[],
int flags)
himport_r(&env_htab, (const char *)default_environment,
sizeof(default_environment), '\0',
flags, 0, nvars, vars);
+ env_amend_default_from_fdt(flags, nvars, vars);
}
/*
--
2.23.0
