From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Glass Date: Wed, 21 Apr 2021 19:14:50 +1200 Subject: [PATCH 1/2] env: allow environment to be amended from control dtb In-Reply-To: <20210413224345.2692591-2-rasmus.villemoes@prevas.dk> References: <20210413224345.2692591-1-rasmus.villemoes@prevas.dk> <20210413224345.2692591-2-rasmus.villemoes@prevas.dk> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Rasmus, On Wed, 14 Apr 2021 at 10:43, Rasmus Villemoes wrote: > > 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. > > Signed-off-by: Rasmus Villemoes > --- > common/board_r.c | 2 ++ > env/Kconfig | 18 ++++++++++++++++++ > env/common.c | 23 +++++++++++++++++++++++ > include/env.h | 15 +++++++++++++++ > include/env_default.h | 3 +++ > 5 files changed, 61 insertions(+) > Reviewed-by: Simon Glass Some suggestions below > diff --git a/common/board_r.c b/common/board_r.c > index c835ff8e26..3f82404772 100644 > --- a/common/board_r.c > +++ b/common/board_r.c > @@ -459,6 +459,8 @@ static int initr_env(void) > else > env_set_default(NULL, 0); > > + env_import_fdt(); > + > if (IS_ENABLED(CONFIG_OF_CONTROL)) > env_set_hex("fdtcontroladdr", > (unsigned long)map_to_sysmem(gd->fdt_blob)); > diff --git a/env/Kconfig b/env/Kconfig > index b473d7cfe1..aa800e37ce 100644 > --- a/env/Kconfig > +++ b/env/Kconfig > @@ -647,6 +647,24 @@ 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 2ee423beb5..af45e561ce 100644 > --- a/env/common.c > +++ b/env/common.c > @@ -345,3 +345,26 @@ 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 void *blob = gd->fdt_blob; > + const char *path; > + int offset, prop; > + > + path = env_get("env_fdt_path"); > + if (!path || !path[0]) > + return; How about returning an error code indicating what happened? > + offset = fdt_path_offset(blob, path); Could we use the livetree API here (ofnode)? > + if (offset < 0) > + return; > + > + fdt_for_each_property_offset(prop, blob, offset) { > + const char *name, *val; > + > + val = fdt_getprop_by_offset(blob, prop, &name, NULL); > + env_set(name, val); > + } > +} > +#endif > diff --git a/include/env.h b/include/env.h > index c15339a93f..6296502595 100644 > --- a/include/env.h > +++ b/include/env.h > @@ -377,4 +377,19 @@ 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" > -- > 2.29.2 > Regards, Simon