imx: Introduce CONFIG_SPL_FORCE_MMC_BOOT to force MMC boot on falcon mode
This change tries to fix the following problem:
- The board boots (to be more precise - ROM loads SPL) from a slow SPI-NOR
memory.
As a result the spl_boot_device() will return SPI-NOR as a boot device
(which is correct).
- The problem is that in 'falcon boot' the eMMC is used as a boot medium to
load kernel from its partition.
Calling spl_boot_device() will break things as it returns SPI-NOR device.
To fix this issue the new CONFIG_SPL_FORCE_MMC_BOOT Kconfig flag is
introduced to handle this special use case. By default it is not defined,
so there is no change in the legacy code flow.
Signed-off-by: Lukasz Majewski <lukma@denx.de>
diff --git a/arch/arm/mach-imx/spl.c b/arch/arm/mach-imx/spl.c
index a98fab8..cda7192 100644
--- a/arch/arm/mach-imx/spl.c
+++ b/arch/arm/mach-imx/spl.c
@@ -178,7 +178,18 @@
/* called from spl_mmc to see type of boot mode for storage (RAW or FAT) */
u32 spl_boot_mode(const u32 boot_device)
{
+/*
+ * When CONFIG_SPL_FORCE_MMC_BOOT is defined the 'boot_device' is used
+ * unconditionally to decide about device to use for booting.
+ * This is crucial for falcon boot mode, when board boots up (i.e. ROM
+ * loads SPL) from slow SPI-NOR memory and afterwards the SPL's 'falcon' boot
+ * mode is used to load Linux OS from eMMC partition.
+ */
+#ifdef CONFIG_SPL_FORCE_MMC_BOOT
+ switch (boot_device) {
+#else
switch (spl_boot_device()) {
+#endif
/* for MMC return either RAW or FAT mode */
case BOOT_DEVICE_MMC1:
case BOOT_DEVICE_MMC2: