If we have a writeable environment in persistent storage and
CONFIG_CMD_LOADENV is set, add the command "loadenv" to load a new environment.

This is to be used for getting access to the persistent environment stored in
NAND after we've booted the GTA02 from NOR.

This patch also adds a command "defaultenv" that resets the environment to the
hard-coded default settings, which is also useful without "loadenv".

Note that we don't scan the new environment for changes in settings (e.g.,
"stdout"). This is to ensure that we don't accidently cut ourselves off during
environmental surgery.

Signed-off-by: Werner Almesberger <werner@openmoko.org>

loadenv.patch:
- common/cmd_nvedit.c (do_loadenv): load the environment from persistent
  storage (without updating settings derived from the environment)
- common/cmd_nvedit.c (do_defaultenv): reset the environment to default
  settings
- include/configs/neo1973_gta02.h: added CONFIG_CMD_LOADENV and
  CONFIG_CMD_DEFAULTENV

Index: u-boot/common/cmd_nvedit.c
===================================================================
--- u-boot.orig/common/cmd_nvedit.c
+++ u-boot/common/cmd_nvedit.c
@@ -563,7 +563,36 @@
 	return (saveenv() ? 1 : 0);
 }
 
-#endif
+#ifdef CONFIG_CMD_LOADENV
+int do_loadenv(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	extern void env_relocate_spec(void);
+	extern char *env_name_spec;
+	extern env_t *env_ptr;
+
+	printf("Loading Environment from %s...\n", env_name_spec);
+
+	if (env_init())
+		return 1;
+	env_relocate_spec();
+	gd->env_addr = (ulong) &env_ptr->data;
+	return 0;
+}
+#endif /* CONFIG_CMD_LOADENV */
+
+#endif /* we have a writeable environment */
+
+#ifdef CONFIG_CMD_DEFAULTENV
+int do_defaultenv(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	extern char *env_name_spec;
+
+	printf("Environment reset to default settings\n");
+
+	default_env();
+	return 0;
+}
+#endif /* CONFIG_CMD_DEFAULTENV */
 
 
 /************************************************************************
@@ -615,7 +644,23 @@
 	NULL
 );
 
-#endif
+#ifdef CONFIG_CMD_LOADENV
+U_BOOT_CMD(
+	loadenv, 1, 0,	do_loadenv,
+	"loadenv - load environment variables from persistent storage\n",
+	NULL
+);
+#endif /* CONFIG_CMD_LOADENV */
+
+#endif /* we have a writeable environment */
+
+#ifdef CONFIG_CMD_DEFAULTENV
+U_BOOT_CMD(
+	defaultenv, 1, 0, do_defaultenv,
+	"defaultenv - reset environment to default settings\n",
+	NULL
+);
+#endif /* CONFIG_CMD_DEFAULTENV */
 
 #if defined(CONFIG_CMD_ASKENV)
 
Index: u-boot/include/configs/neo1973_gta02.h
===================================================================
--- u-boot.orig/include/configs/neo1973_gta02.h
+++ u-boot/include/configs/neo1973_gta02.h
@@ -192,6 +192,9 @@
 	"stderr=usbtty\0stdout=usbtty\0stdin=usbtty\0"			\
 	"bootargs_base=rootfstype=jffs2 root=/dev/mtdblock6 console=ttySAC2,115200 console=tty0 loglevel=8\0" \
 	""
+#define CONFIG_CMD_LOADENV
+#define CONFIG_CMD_DEFAULTENV
+
 
 /*-----------------------------------------------------------------------
  * Physical Memory Map