mmc: sdhci-esdhc-imx: fix multiblock reads on i.MX53

The eSDHC controller on the i.MX53 needs an additional, non spec
compliant CMD12 after a multiblock read with a predefined number of
blocks. Otherwise the internal state machine won't go back to the
idle state.

This commit effectively reverts 5b6b0ad6 (mmc: sdhci-esdhc-imx:
fix for mmc cards on i.MX5), which fixed part of the problem by
making multiblock reads work, however this fix was not sufficient
when multi- and singleblock reads got intermixed.

This implements the recommended workaround (Freescale i.MX Reference
Manual, section 29.6.8 "Multi-block Read") by manually sending a
CMD12 with the RSPTYP bits cleared.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 34 insertions, 3 deletions

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 9b0a0a91ea0a..d5f0d59e1310 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -85,6 +85,12 @@ struct pltfm_imx_data {
         struct clk *clk_ipg;
         struct clk *clk_ahb;
         struct clk *clk_per;
+        enum {
+                NO_CMD_PENDING,      /* no multiblock command pending*/
+                MULTIBLK_IN_PROCESS, /* exact multiblock cmd in process */
+                WAIT_FOR_INT,        /* sent CMD12, waiting for response INT */
+        } multiblock_status;
+
 };
 
 static struct platform_device_id imx_esdhc_devtype[] = {
@@ -154,6 +160,8 @@ static inline void esdhc_clrset_le(struct sdhci_host *host, u32 mask, u32 val, i
 
 static u32 esdhc_readl_le(struct sdhci_host *host, int reg)
 {
+        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+        struct pltfm_imx_data *imx_data = pltfm_host->priv;
         u32 val = readl(host->ioaddr + reg);
 
         if (unlikely(reg == SDHCI_CAPABILITIES)) {
@@ -175,6 +183,18 @@ static u32 esdhc_readl_le(struct sdhci_host *host, int reg)
                         val &= ~ESDHC_INT_VENDOR_SPEC_DMA_ERR;
                         val |= SDHCI_INT_ADMA_ERROR;
                 }
+
+                /*
+                 * mask off the interrupt we get in response to the manually
+                 * sent CMD12
+                 */
+                if ((imx_data->multiblock_status == WAIT_FOR_INT) &&
+                    ((val & SDHCI_INT_RESPONSE) == SDHCI_INT_RESPONSE)) {
+                        val &= ~SDHCI_INT_RESPONSE;
+                        writel(SDHCI_INT_RESPONSE, host->ioaddr +
+                                                   SDHCI_INT_STATUS);
+                        imx_data->multiblock_status = NO_CMD_PENDING;
+                }
         }
 
         return val;
@@ -211,6 +231,15 @@ static void esdhc_writel_le(struct sdhci_host *host, u32 val, int reg)
                         v = readl(host->ioaddr + ESDHC_VENDOR_SPEC);
                         v &= ~ESDHC_VENDOR_SPEC_SDIO_QUIRK;
                         writel(v, host->ioaddr + ESDHC_VENDOR_SPEC);
+
+                        if (imx_data->multiblock_status == MULTIBLK_IN_PROCESS)
+                        {
+                                /* send a manual CMD12 with RESPTYP=none */
+                                data = MMC_STOP_TRANSMISSION << 24 |
+                                       SDHCI_CMD_ABORTCMD << 16;
+                                writel(data, host->ioaddr + SDHCI_TRANSFER_MODE);
+                                imx_data->multiblock_status = WAIT_FOR_INT;
+                        }
         }
 
         if (unlikely(reg == SDHCI_INT_ENABLE || reg == SDHCI_SIGNAL_ENABLE)) {
@@ -277,11 +306,13 @@ static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
                 }
                 return;
         case SDHCI_COMMAND:
-                if ((host->cmd->opcode == MMC_STOP_TRANSMISSION ||
-                     host->cmd->opcode == MMC_SET_BLOCK_COUNT) &&
-                    (imx_data->flags & ESDHC_FLAG_MULTIBLK_NO_INT))
+                if (host->cmd->opcode == MMC_STOP_TRANSMISSION)
                         val |= SDHCI_CMD_ABORTCMD;
 
+                if ((host->cmd->opcode == MMC_SET_BLOCK_COUNT) &&
+                    (imx_data->flags & ESDHC_FLAG_MULTIBLK_NO_INT))
+                        imx_data->multiblock_status = MULTIBLK_IN_PROCESS;
+
                 if (is_imx6q_usdhc(imx_data))
                         writel(val << 16,
                                host->ioaddr + SDHCI_TRANSFER_MODE);