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>

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 9b0a0a9..d5f0d59 100644 (file)
--- 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);