[U-Boot] [PATCH V2 3/4] imx: mx6: implement mmc_get_env_devno

[Peng Fan]

Implement mmc_get_env_devno, devno can be got from smbr1 of SRC.
Introduce a weak function board_mmc_get_env_devno, different
boards can implement it according to different sdhc controllers
that used by the board.

Signed-off-by: Peng Fan <peng.fan at nxp.com>
Cc: Stefano Babic <sbabic at denx.de>
---

Changes V2:
 move mmc_get_env_devno into soc.c

 arch/arm/cpu/armv7/mx6/soc.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index bf5ae8c..fd383f2 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -349,6 +349,36 @@ int arch_cpu_init(void)
 	return 0;
 }
 
+__weak int board_mmc_get_env_devno(int devno)
+{
+	return CONFIG_SYS_MMC_ENV_DEV;
+}
+
+int mmc_get_env_devno(void)
+{
+	struct src *src_regs = (struct src *)SRC_BASE_ADDR;
+	u32 soc_sbmr = readl(&src_regs->sbmr1);
+	u32 bootsel;
+	int devno;
+
+	/*
+	 * Refer to
+	 * "i.MX 6Dual/6Quad Applications Processor Reference Manual"
+	 * Chapter "8.5.3.1 Expansion Device eFUSE Configuration"
+	 * i.MX6SL/SX/UL has same layout.
+	 */
+	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] */
+	devno = (soc_sbmr & 0x00001800) >> 11;
+
+	return board_mmc_get_env_devno(devno);
+}
+
 int board_postclk_init(void)
 {
 	set_ldo_voltage(LDO_SOC, 1175);	/* Set VDDSOC to 1.175V */
-- 
2.6.2