sdhci: handle bug in JMB38x for sizes < 4 bytes

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

3 files changed, 13 insertions, 1 deletions

diff --git a/drivers/mmc/host/sdhci-pci.c b/drivers/mmc/host/sdhci-pci.c
index deb607c52c0d..fcb14c2346cc 100644
--- a/drivers/mmc/host/sdhci-pci.c
+++ b/drivers/mmc/host/sdhci-pci.c
@@ -143,7 +143,8 @@ static int jmicron_probe(struct sdhci_pci_chip *chip)
                 chip->quirks |= SDHCI_QUIRK_32BIT_DMA_ADDR |
                           SDHCI_QUIRK_32BIT_DMA_SIZE |
                           SDHCI_QUIRK_32BIT_ADMA_SIZE |
-                          SDHCI_QUIRK_RESET_AFTER_REQUEST;
+                          SDHCI_QUIRK_RESET_AFTER_REQUEST |
+                          SDHCI_QUIRK_BROKEN_SMALL_PIO;
         }
 
         /*
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 5f95e10229b5..be09739f692d 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -278,6 +278,15 @@ static void sdhci_transfer_pio(struct sdhci_host *host)
         else
                 mask = SDHCI_SPACE_AVAILABLE;
 
+        /*
+         * Some controllers (JMicron JMB38x) mess up the buffer bits
+         * for transfers < 4 bytes. As long as it is just one block,
+         * we can ignore the bits.
+         */
+        if ((host->quirks & SDHCI_QUIRK_BROKEN_SMALL_PIO) &&
+                (host->data->blocks == 1))
+                mask = ~0;
+
         while (readl(host->ioaddr + SDHCI_PRESENT_STATE) & mask) {
                 if (host->data->flags & MMC_DATA_READ)
                         sdhci_read_block_pio(host);
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index e354faee5df0..197d4a05f4ae 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -206,6 +206,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER             (1<<11)
 /* Controller provides an incorrect timeout value for transfers */
 #define SDHCI_QUIRK_BROKEN_TIMEOUT_VAL                  (1<<12)
+/* Controller has an issue with buffer bits for small transfers */
+#define SDHCI_QUIRK_BROKEN_SMALL_PIO                    (1<<13)
 
         int                     irq;            /* Device IRQ */
         void __iomem *          ioaddr;         /* Mapped address */