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 a98fab8f1cee4f5f46f7296423ec1cb869cd5529..cda719226aae07d589044007b550f3b1f89fcbbc 100644 (file)
--- a/arch/arm/mach-imx/spl.c
+++ b/arch/arm/mach-imx/spl.c
@@ -178,7 +178,18 @@ int g_dnl_bind_fixup(struct usb_device_descriptor *dev, const char *name)
 /* 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:

diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 2ca219995dde99bde1ef0245e39f38c242081968..f59b6f5b51f41b80073ab72ac5ebf847983651f3 100644 (file)
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -608,6 +608,15 @@ config SPL_MMC_SUPPORT
          this option to build the drivers in drivers/mmc as part of an SPL
          build.
 
+config SPL_FORCE_MMC_BOOT
+       bool "Force SPL booting from MMC"
+       depends on SPL_MMC_SUPPORT
+       default n
+       help
+         Force SPL to use MMC device for Linux kernel booting even when the
+         SoC ROM recognized boot medium is not eMMC/SD. This is crucial for
+         factory or 'falcon mode' booting.
+
 config SPL_MMC_TINY
        bool "Tiny MMC framework in SPL"
        depends on SPL_MMC_SUPPORT