[U-Boot] [PATCH 4/5] imx: mx6slevk: implement mmc_get_env_devno

[Peng Fan <Peng.Fan@freescale.com>]

Implement mmc_get_env_devno, support loading env successfully
when booting from different slots.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
---
 board/freescale/mx6slevk/mx6slevk.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/board/freescale/mx6slevk/mx6slevk.c b/board/freescale/mx6slevk/mx6slevk.c
index 5eab4b5..7617c76 100644
--- a/board/freescale/mx6slevk/mx6slevk.c
+++ b/board/freescale/mx6slevk/mx6slevk.c
@@ -170,6 +170,22 @@ static struct fsl_esdhc_cfg usdhc_cfg[3] = {
 	{USDHC3_BASE_ADDR, 0, 4},
 };
 
+int mmc_get_env_devno(void)
+{
+	struct src *src_regs = (struct src *)SRC_BASE_ADDR;
+	u32 soc_sbmr = readl(&src_regs->sbmr1);
+	u32 bootsel;
+
+	bootsel = (soc_sbmr & 0x000000FF) >> 6 ;
+
+	/* If not boot from sd/mmc, use default value */
+	if (bootsel != 1)
+		return CONFIG_SYS_MMC_ENV_DEV;
+
+	/* BOOT_CFG2[3] and BOOT_CFG2[4] */
+	return (soc_sbmr & 0x00001800) >> 11;
+}
+
 int board_mmc_getcd(struct mmc *mmc)
 {
 	struct fsl_esdhc_cfg *cfg = (struct fsl_esdhc_cfg *)mmc->priv;
-- 
2.6.2