mmc: Downgrade SD/MMC from UHS/HS200/HS400 modes before boot

Older kernel versions or systems which do not connect eMMC reset line
properly may not be able to handle situations where either the eMMC
is left in HS200/HS400 mode or SD card in UHS modes by the bootloader
and may misbehave. Downgrade the eMMC to HS/HS52 mode and/or SD card
to non-UHS mode before booting the kernel to allow such older kernels
to work with modern U-Boot.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Tom Rini <trini@konsulko.com>

diff --git a/drivers/mmc/mmc-uclass.c b/drivers/mmc/mmc-uclass.c
index 76225b7939bb06c3e761752d0b6e156d8c7e1d46..a9c8f335c142de56df370660986347652a51c66c 100644 (file)
--- a/drivers/mmc/mmc-uclass.c
+++ b/drivers/mmc/mmc-uclass.c
@@ -368,6 +368,19 @@ static int mmc_blk_probe(struct udevice *dev)
        return 0;
 }
 
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS200_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS400_SUPPORT)
+static int mmc_blk_remove(struct udevice *dev)
+{
+       struct udevice *mmc_dev = dev_get_parent(dev);
+       struct mmc_uclass_priv *upriv = dev_get_uclass_priv(mmc_dev);
+       struct mmc *mmc = upriv->mmc;
+
+       return mmc_deinit(mmc);
+}
+#endif
+
 static const struct blk_ops mmc_blk_ops = {
        .read   = mmc_bread,
 #if CONFIG_IS_ENABLED(MMC_WRITE)
@@ -382,6 +395,12 @@ U_BOOT_DRIVER(mmc_blk) = {
        .id             = UCLASS_BLK,
        .ops            = &mmc_blk_ops,
        .probe          = mmc_blk_probe,
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS200_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS400_SUPPORT)
+       .remove         = mmc_blk_remove,
+       .flags          = DM_FLAG_OS_PREPARE,
+#endif
 };
 #endif /* CONFIG_BLK */
 

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index b04345a1e1518227c0a48845b06dfe2912954fda..1c1527cc747465ae6a2d4ec971595675b233ff7e 100644 (file)
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -2781,6 +2781,32 @@ int mmc_init(struct mmc *mmc)
        return err;
 }
 
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS200_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS400_SUPPORT)
+int mmc_deinit(struct mmc *mmc)
+{
+       u32 caps_filtered;
+
+       if (!mmc->has_init)
+               return 0;
+
+       if (IS_SD(mmc)) {
+               caps_filtered = mmc->card_caps &
+                       ~(MMC_CAP(UHS_SDR12) | MMC_CAP(UHS_SDR25) |
+                         MMC_CAP(UHS_SDR50) | MMC_CAP(UHS_DDR50) |
+                         MMC_CAP(UHS_SDR104));
+
+               return sd_select_mode_and_width(mmc, caps_filtered);
+       } else {
+               caps_filtered = mmc->card_caps &
+                       ~(MMC_CAP(MMC_HS_200) | MMC_CAP(MMC_HS_400));
+
+               return mmc_select_mode_and_width(mmc, caps_filtered);
+       }
+}
+#endif
+
 int mmc_set_dsr(struct mmc *mmc, u16 val)
 {
        mmc->dsr = val;

diff --git a/include/mmc.h b/include/mmc.h
index d84e4fca73706ee008586a2f79122b653a3de0b2..1f30f71d25f8cda5ac77f6a6a9ca07fe9ed38d51 100644 (file)
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -690,6 +690,12 @@ int mmc_initialize(bd_t *bis);
 int mmc_init(struct mmc *mmc);
 int mmc_send_tuning(struct mmc *mmc, u32 opcode, int *cmd_error);
 
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS200_SUPPORT) || \
+    CONFIG_IS_ENABLED(MMC_HS400_SUPPORT)
+int mmc_deinit(struct mmc *mmc);
+#endif
+
 /**
  * mmc_of_parse() - Parse the device tree to get the capabilities of the host
  *