mmc: sdhci-esdhc-imx: add basic imx6q usdhc support

This patch adds the basic support for imx6q usdhc, which is a
derivative of esdhc controller.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

2 files changed, 35 insertions, 7 deletions

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index c226d549fd2f..87d5067ba629 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -130,13 +130,13 @@ config MMC_SDHCI_CNS3XXX
           If unsure, say N.
 
 config MMC_SDHCI_ESDHC_IMX
-        tristate "SDHCI platform support for the Freescale eSDHC i.MX controller"
+        tristate "SDHCI support for the Freescale eSDHC/uSDHC i.MX controller"
         depends on ARCH_MXC
         depends on MMC_SDHCI_PLTFM
         select MMC_SDHCI_IO_ACCESSORS
         help
-          This selects the Freescale eSDHC controller support on the platform
-          bus, found on i.MX25, i.MX35 and i.MX5x.
+          This selects the Freescale eSDHC/uSDHC controller support
+          found on i.MX25, i.MX35 i.MX5x and i.MX6x.
 
           If you have a controller with this interface, say Y or M here.
 
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 4557aa1567a5..ae57769ba50d 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -32,6 +32,7 @@
 /* VENDOR SPEC register */
 #define SDHCI_VENDOR_SPEC               0xC0
 #define  SDHCI_VENDOR_SPEC_SDIO_QUIRK   0x00000002
+#define SDHCI_MIX_CTRL                  0x48
 
 /*
  * There is an INT DMA ERR mis-match between eSDHC and STD SDHC SPEC:
@@ -59,6 +60,7 @@ enum imx_esdhc_type {
         IMX35_ESDHC,
         IMX51_ESDHC,
         IMX53_ESDHC,
+        IMX6Q_USDHC,
 };
 
 struct pltfm_imx_data {
@@ -82,6 +84,9 @@ static struct platform_device_id imx_esdhc_devtype[] = {
                 .name = "sdhci-esdhc-imx53",
                 .driver_data = IMX53_ESDHC,
         }, {
+                .name = "sdhci-usdhc-imx6q",
+                .driver_data = IMX6Q_USDHC,
+        }, {
                 /* sentinel */
         }
 };
@@ -92,6 +97,7 @@ static const struct of_device_id imx_esdhc_dt_ids[] = {
         { .compatible = "fsl,imx35-esdhc", .data = &imx_esdhc_devtype[IMX35_ESDHC], },
         { .compatible = "fsl,imx51-esdhc", .data = &imx_esdhc_devtype[IMX51_ESDHC], },
         { .compatible = "fsl,imx53-esdhc", .data = &imx_esdhc_devtype[IMX53_ESDHC], },
+        { .compatible = "fsl,imx6q-usdhc", .data = &imx_esdhc_devtype[IMX6Q_USDHC], },
         { /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, imx_esdhc_dt_ids);
@@ -116,6 +122,11 @@ static inline int is_imx53_esdhc(struct pltfm_imx_data *data)
         return data->devtype == IMX53_ESDHC;
 }
 
+static inline int is_imx6q_usdhc(struct pltfm_imx_data *data)
+{
+        return data->devtype == IMX6Q_USDHC;
+}
+
 static inline void esdhc_clrset_le(struct sdhci_host *host, u32 mask, u32 val, int reg)
 {
         void __iomem *base = host->ioaddr + (reg & ~0x3);
@@ -220,8 +231,16 @@ static void esdhc_writel_le(struct sdhci_host *host, u32 val, int reg)
 
 static u16 esdhc_readw_le(struct sdhci_host *host, int reg)
 {
-        if (unlikely(reg == SDHCI_HOST_VERSION))
-                reg ^= 2;
+        if (unlikely(reg == SDHCI_HOST_VERSION)) {
+                u16 val = readw(host->ioaddr + (reg ^ 2));
+                /*
+                 * uSDHC supports SDHCI v3.0, but it's encoded as value
+                 * 0x3 in host controller version register, which violates
+                 * SDHCI_SPEC_300 definition.  Work it around here.
+                 */
+                if ((val & SDHCI_SPEC_VER_MASK) == 3)
+                        return --val;
+        }
 
         return readw(host->ioaddr + reg);
 }
@@ -252,8 +271,17 @@ static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
                 if ((host->cmd->opcode == MMC_STOP_TRANSMISSION)
                         && (imx_data->flags & ESDHC_FLAG_MULTIBLK_NO_INT))
                         val |= SDHCI_CMD_ABORTCMD;
-                writel(val << 16 | imx_data->scratchpad,
-                        host->ioaddr + SDHCI_TRANSFER_MODE);
+
+                if (is_imx6q_usdhc(imx_data)) {
+                        u32 m = readl(host->ioaddr + SDHCI_MIX_CTRL);
+                        m = imx_data->scratchpad | (m & 0xffff0000);
+                        writel(m, host->ioaddr + SDHCI_MIX_CTRL);
+                        writel(val << 16,
+                               host->ioaddr + SDHCI_TRANSFER_MODE);
+                } else {
+                        writel(val << 16 | imx_data->scratchpad,
+                               host->ioaddr + SDHCI_TRANSFER_MODE);
+                }
                 return;
         case SDHCI_BLOCK_SIZE:
                 val &= ~SDHCI_MAKE_BLKSZ(0x7, 0);