board: stm32mp1: use CONFIG_SYS_MMC_ENV_DEV when available

Check whether user has explicitly defined the mmc device to use
in mmc_get_env_dev() with CONFIG_SYS_MMC_ENV_DEV.

On STMicroelectronics boards the used mmc device for environment is
the instance of boot device provided by the ROM code; the mmc instance
is configured by alias in device tree. The used partition is defined in
device tree with u-boot,mmc-env-partition = "ssbl".

This patch allows to override this selection for the support of customer
boards without alias; for example when SDMMC1 is not used and ENV in
mmc0=SDMMC2, user can force the value: CONFIG_SYS_MMC_ENV_DEV = 0.

On STMicroelectronics boards, the current behavior is kept with
CONFIG_SYS_MMC_ENV_DEV = -1.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>

board/st/stm32mp1/stm32mp1.c

@@ -862,8 +862,14 @@ const char *env_ext4_get_dev_part(void)
 
 int mmc_get_env_dev(void)
 {
-	u32 bootmode = get_bootmode();
+	u32 bootmode;
+
+	if (CONFIG_SYS_MMC_ENV_DEV >= 0)
+		return CONFIG_SYS_MMC_ENV_DEV;
+
+	bootmode = get_bootmode();
 
+	/* use boot instance to select the correct mmc device identifier */
 	return (bootmode & TAMP_BOOT_INSTANCE_MASK) - 1;
 }
 

configs/stm32mp15_basic_defconfig

@@ -72,6 +72,7 @@ CONFIG_ENV_UBI_PART="UBI"
 CONFIG_ENV_UBI_VOLUME="uboot_config"
 CONFIG_ENV_UBI_VOLUME_REDUND="uboot_config_r"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_SYS_MMC_ENV_DEV=-1
 # CONFIG_SPL_ENV_IS_NOWHERE is not set
 # CONFIG_SPL_ENV_IS_IN_SPI_FLASH is not set
 CONFIG_STM32_ADC=y

configs/stm32mp15_trusted_defconfig

@@ -53,6 +53,7 @@ CONFIG_ENV_UBI_PART="UBI"
 CONFIG_ENV_UBI_VOLUME="uboot_config"
 CONFIG_ENV_UBI_VOLUME_REDUND="uboot_config_r"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_SYS_MMC_ENV_DEV=-1
 CONFIG_STM32_ADC=y
 CONFIG_CLK_SCMI=y
 CONFIG_SET_DFU_ALT_INFO=y