[U-Boot] [PATCH V2 2/4] common: env_mmc: support loading env from different cards

[Peng Fan]

Some boards support booting from different SD card slots.
For example, mx6dpsabresd board supports booting from SD2,
SD3, EMMC4, using different boot switch. And the index
numbers are SD2(0), SD3(1), EMMC4(2).
But CONFIG_SYS_MMC_ENV_DEV is hardcoded to 1(for SD3), so when
booting from SD2(using 0), uboot complains "MMC: no card present",
since there is no card in SD3 slot.

This patch introduces a weak function which still returns
CONFIG_SYS_MMC_ENV_DEV to avoid break other boards. Then
different boards can implement mmc_get_env_devno to read
env from the correct sd/emmc.

Signed-off-by: Peng Fan <peng.fan at nxp.com>
Cc: Stefano Babic <sbabic at denx.de>
Cc: Simon Glass <sjg at chromium.org>
Cc: Tim Harvey <tharvey at gateworks.com>
Cc: Hans de Goede <hdegoede at redhat.com>
---

Changes V2:
 none.

 common/env_mmc.c | 22 ++++++++++++++--------
 include/mmc.h    |  1 +
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/common/env_mmc.c b/common/env_mmc.c
index 9639822..857e20c 100644
--- a/common/env_mmc.c
+++ b/common/env_mmc.c
@@ -63,6 +63,11 @@ int env_init(void)
 	return 0;
 }
 
+__weak int mmc_get_env_devno(void)
+{
+	return CONFIG_SYS_MMC_ENV_DEV;
+}
+
 #ifdef CONFIG_SYS_MMC_ENV_PART
 __weak uint mmc_get_env_part(struct mmc *mmc)
 {
@@ -72,7 +77,7 @@ __weak uint mmc_get_env_part(struct mmc *mmc)
 static int mmc_set_env_part(struct mmc *mmc)
 {
 	uint part = mmc_get_env_part(mmc);
-	int dev = CONFIG_SYS_MMC_ENV_DEV;
+	int dev = mmc_get_env_devno();
 	int ret = 0;
 
 #ifdef CONFIG_SPL_BUILD
@@ -108,7 +113,7 @@ static const char *init_mmc_for_env(struct mmc *mmc)
 static void fini_mmc_for_env(struct mmc *mmc)
 {
 #ifdef CONFIG_SYS_MMC_ENV_PART
-	int dev = CONFIG_SYS_MMC_ENV_DEV;
+	int dev = mmc_get_env_devno();
 
 #ifdef CONFIG_SPL_BUILD
 	dev = 0;
@@ -127,7 +132,7 @@ static inline int write_env(struct mmc *mmc, unsigned long size,
 	blk_start	= ALIGN(offset, mmc->write_bl_len) / mmc->write_bl_len;
 	blk_cnt		= ALIGN(size, mmc->write_bl_len) / mmc->write_bl_len;
 
-	n = mmc->block_dev.block_write(CONFIG_SYS_MMC_ENV_DEV, blk_start,
+	n = mmc->block_dev.block_write(mmc_get_env_devno(), blk_start,
 					blk_cnt, (u_char *)buffer);
 
 	return (n == blk_cnt) ? 0 : -1;
@@ -140,7 +145,8 @@ static unsigned char env_flags;
 int saveenv(void)
 {
 	ALLOC_CACHE_ALIGN_BUFFER(env_t, env_new, 1);
-	struct mmc *mmc = find_mmc_device(CONFIG_SYS_MMC_ENV_DEV);
+	int mmc_env_devno = mmc_get_env_devno();
+	struct mmc *mmc = find_mmc_device(mmc_env_devno);
 	u32	offset;
 	int	ret, copy = 0;
 	const char *errmsg;
@@ -168,7 +174,7 @@ int saveenv(void)
 	}
 
 	printf("Writing to %sMMC(%d)... ", copy ? "redundant " : "",
-	       CONFIG_SYS_MMC_ENV_DEV);
+	       mmc_env_devno);
 	if (write_env(mmc, CONFIG_ENV_SIZE, offset, (u_char *)env_new)) {
 		puts("failed\n");
 		ret = 1;
@@ -192,7 +198,7 @@ static inline int read_env(struct mmc *mmc, unsigned long size,
 			   unsigned long offset, const void *buffer)
 {
 	uint blk_start, blk_cnt, n;
-	int dev = CONFIG_SYS_MMC_ENV_DEV;
+	int dev = mmc_get_env_devno();
 
 #ifdef CONFIG_SPL_BUILD
 	dev = 0;
@@ -216,7 +222,7 @@ void env_relocate_spec(void)
 	int crc1_ok = 0, crc2_ok = 0;
 	env_t *ep;
 	int ret;
-	int dev = CONFIG_SYS_MMC_ENV_DEV;
+	int dev = mmc_get_env_devno();
 	const char *errmsg = NULL;
 
 	ALLOC_CACHE_ALIGN_BUFFER(env_t, tmp_env1, 1);
@@ -302,7 +308,7 @@ void env_relocate_spec(void)
 	struct mmc *mmc;
 	u32 offset;
 	int ret;
-	int dev = CONFIG_SYS_MMC_ENV_DEV;
+	int dev = mmc_get_env_devno();
 	const char *errmsg;
 
 #ifdef CONFIG_SPL_BUILD
diff --git a/include/mmc.h b/include/mmc.h
index cda9a19..e70aedb 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -475,6 +475,7 @@ void board_mmc_power_init(void);
 int board_mmc_init(bd_t *bis);
 int cpu_mmc_init(bd_t *bis);
 int mmc_get_env_addr(struct mmc *mmc, int copy, u32 *env_addr);
+int mmc_get_env_devno(void);
 
 struct pci_device_id;
 
-- 
2.6.2