env_mmc: support env partition setup in runtime

Add callback with __weak annotation to allow setup of environment
partition number in runtime from a board file.

Propagate mmc_switch_part() return value into init_mmc_for_env() instead
of -1 in case of failure.

Signed-off-by: Dmitry Lifshitz <lifshitz@compulab.co.il>
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>

common/env_mmc.c

@@ -62,16 +62,36 @@ int env_init(void)
 	return 0;
 }
 
-static int init_mmc_for_env(struct mmc *mmc)
-{
 #ifdef CONFIG_SYS_MMC_ENV_PART
+__weak uint mmc_get_env_part(struct mmc *mmc)
+{
+	return CONFIG_SYS_MMC_ENV_PART;
+}
+
+static int mmc_set_env_part(struct mmc *mmc)
+{
+	uint part = mmc_get_env_part(mmc);
 	int dev = CONFIG_SYS_MMC_ENV_DEV;
+	int ret = 0;
 
 #ifdef CONFIG_SPL_BUILD
 	dev = 0;
 #endif
+
+	if (part != mmc->part_num) {
+		ret = mmc_switch_part(dev, part);
+		if (ret)
+			puts("MMC partition switch failed\n");
+	}
+
+	return ret;
+}
+#else
+static inline int mmc_set_env_part(struct mmc *mmc) {return 0; };
 #endif
 
+static int init_mmc_for_env(struct mmc *mmc)
+{
 	if (!mmc) {
 		puts("No MMC card found\n");
 		return -1;
@@ -82,16 +102,7 @@ static int init_mmc_for_env(struct mmc *mmc)
 		return -1;
 	}
 
-#ifdef CONFIG_SYS_MMC_ENV_PART
-	if (CONFIG_SYS_MMC_ENV_PART != mmc->part_num) {
-		if (mmc_switch_part(dev, CONFIG_SYS_MMC_ENV_PART)) {
-			puts("MMC partition switch failed\n");
-			return -1;
-		}
-	}
-#endif
-
-	return 0;
+	return mmc_set_env_part(mmc);
 }
 
 static void fini_mmc_for_env(struct mmc *mmc)

include/environment.h

@@ -184,6 +184,9 @@ extern void env_reloc(void);
 #include <mmc.h>
 
 extern int mmc_get_env_addr(struct mmc *mmc, int copy, u32 *env_addr);
+# ifdef CONFIG_SYS_MMC_ENV_PART
+extern uint mmc_get_env_part(struct mmc *mmc);
+# endif
 #endif
 
 #ifndef DO_DEPS_ONLY