[U-Boot] [PATCH v4 1/4] env: register erase command

[Frank Wunderlich]

this patch adds basic changes for adding a erase-subcommand to env

with this command the environment stored on non-volatile storage written
by saveenv can be cleared.

Signed-off-by: Frank Wunderlich <frank-w at public-files.de>

squashed fixes
 - start message with "Erasing"
 - mark erase-function as optional
 - env: separate eraseenv from saveenv

Suggested-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
---
 cmd/Kconfig           |  8 ++++++++
 cmd/nvedit.c          | 19 +++++++++++++++++++
 env/env.c             | 30 ++++++++++++++++++++++++++++++
 include/environment.h | 17 +++++++++++++++++
 4 files changed, 74 insertions(+)

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 0b07b3b9d7..e8a99cb5a3 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -397,6 +397,14 @@ config CMD_SAVEENV
 	  Save all environment variables into the compiled-in persistent
 	  storage.

+config CMD_ERASEENV
+	bool "eraseenv"
+	default n
+	depends on CMD_SAVEENV
+	help
+	  Erase environment variables from the compiled-in persistent
+	  storage.
+
 config CMD_ENV_EXISTS
 	bool "env exists"
 	default y
diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index 24a6cf7824..0cbd8e8984 100644
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -761,6 +761,19 @@ U_BOOT_CMD(
 	"save environment variables to persistent storage",
 	""
 );
+
+#if defined(CONFIG_CMD_ERASEENV)
+static int do_env_erase(cmd_tbl_t *cmdtp, int flag, int argc,
+			char * const argv[])
+{
+	return env_erase() ? 1 : 0;
+}
+U_BOOT_CMD(
+	eraseenv, 1, 0,	do_env_erase,
+	"erase environment variables from persistent storage",
+	""
+);
+#endif
 #endif
 #endif /* CONFIG_SPL_BUILD */

@@ -1207,6 +1220,9 @@ static cmd_tbl_t cmd_env_sub[] = {
 #endif
 #if defined(CONFIG_CMD_SAVEENV) && !defined(CONFIG_ENV_IS_NOWHERE)
 	U_BOOT_CMD_MKENT(save, 1, 0, do_env_save, "", ""),
+#if defined(CONFIG_CMD_ERASEENV)
+	U_BOOT_CMD_MKENT(erase, 1, 0, do_env_erase, "", ""),
+#endif
 #endif
 	U_BOOT_CMD_MKENT(set, CONFIG_SYS_MAXARGS, 0, do_env_set, "", ""),
 #if defined(CONFIG_CMD_ENV_EXISTS)
@@ -1282,6 +1298,9 @@ static char env_help_text[] =
 #endif
 #if defined(CONFIG_CMD_SAVEENV) && !defined(CONFIG_ENV_IS_NOWHERE)
 	"env save - save environment\n"
+#if defined(CONFIG_CMD_ERASEENV)
+	"env erase - erase environment\n"
+#endif
 #endif
 #if defined(CONFIG_CMD_NVEDIT_EFI)
 	"env set -e name [arg ...] - set UEFI variable; unset if 'arg' not specified\n"
diff --git a/env/env.c b/env/env.c
index 4b417b90a2..d3cbe2f915 100644
--- a/env/env.c
+++ b/env/env.c
@@ -24,6 +24,8 @@ void env_fix_drivers(void)
 			entry->load += gd->reloc_off;
 		if (entry->save)
 			entry->save += gd->reloc_off;
+		if (entry->erase)
+			entry->erase += gd->reloc_off;
 		if (entry->init)
 			entry->init += gd->reloc_off;
 	}
@@ -254,6 +256,34 @@ int env_save(void)
 	return -ENODEV;
 }

+int env_erase(void)
+{
+	struct env_driver *drv;
+
+	drv = env_driver_lookup(ENVOP_ERASE, gd->env_load_prio);
+	if (drv) {
+		int ret;
+
+		if (!drv->erase)
+			return -ENODEV;
+
+		if (!env_has_inited(drv->location))
+			return -ENODEV;
+
+		printf("Erasing Environment on %s... ", drv->name);
+		ret = drv->erase();
+		if (ret)
+			printf("Failed (%d)\n", ret);
+		else
+			printf("OK\n");
+
+		if (!ret)
+			return 0;
+	}
+
+	return -ENODEV;
+}
+
 int env_init(void)
 {
 	struct env_driver *drv;
diff --git a/include/environment.h b/include/environment.h
index cd96676141..de67cf4f0e 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -200,6 +200,7 @@ enum env_operation {
 	ENVOP_INIT,	/* we want to call the init function */
 	ENVOP_LOAD,	/* we want to call the load function */
 	ENVOP_SAVE,	/* we want to call the save function */
+	ENVOP_ERASE,	/* we want to call the erase function */
 };

 struct env_driver {
@@ -225,6 +226,15 @@ struct env_driver {
 	 */
 	int (*save)(void);

+	/**
+	 * erase() - Erase the environment on storage
+	 *
+	 * This method is optional and required for 'eraseenv' to work.
+	 *
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*erase)(void);
+
 	/**
 	 * init() - Set up the initial pre-relocation environment
 	 *
@@ -303,6 +313,13 @@ int env_load(void);
  */
 int env_save(void);

+/**
+ * env_erase() - Erase the environment on storage
+ *
+ * @return 0 if OK, -ve on error
+ */
+int env_erase(void);
+
 /**
  * env_fix_drivers() - Updates envdriver as per relocation
  */
--
2.17.1