mmc: sdhci-cadence: add HS400 enhanced strobe support

Add support for HS400ES mode to Cadence SDHCI driver.

Signed-off-by: Piotr Sroka <piotrs@cadence.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
index 316cfec3f0050a988e42d50129479b58bca233ae..48f641953844ff8749ff929330a4985f3469e056 100644 (file)
--- a/drivers/mmc/host/sdhci-cadence.c
+++ b/drivers/mmc/host/sdhci-cadence.c
@@ -40,6 +40,7 @@
 #define   SDHCI_CDNS_HRS06_MODE_MMC_DDR                0x3
 #define   SDHCI_CDNS_HRS06_MODE_MMC_HS200      0x4
 #define   SDHCI_CDNS_HRS06_MODE_MMC_HS400      0x5
+#define   SDHCI_CDNS_HRS06_MODE_MMC_HS400ES    0x6
 
 /* SRS - Slot Register Set (SDHCI-compatible) */
 #define SDHCI_CDNS_SRS_BASE            0x200
@@ -64,6 +65,7 @@
 
 struct sdhci_cdns_priv {
        void __iomem *hrs_addr;
+       bool enhanced_strobe;
 };
 
 static void sdhci_cdns_write_phy_reg(struct sdhci_cdns_priv *priv,
@@ -108,11 +110,30 @@ static unsigned int sdhci_cdns_get_timeout_clock(struct sdhci_host *host)
        return host->max_clk / 1000;
 }
 
+static void sdhci_cdns_set_emmc_mode(struct sdhci_cdns_priv *priv, u32 mode)
+{
+       u32 tmp;
+
+       /* The speed mode for eMMC is selected by HRS06 register */
+       tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
+       tmp &= ~SDHCI_CDNS_HRS06_MODE_MASK;
+       tmp |= mode;
+       writel(tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
+}
+
+static u32 sdhci_cdns_get_emmc_mode(struct sdhci_cdns_priv *priv)
+{
+       u32 tmp;
+
+       tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
+       return tmp & SDHCI_CDNS_HRS06_MODE_MASK;
+}
+
 static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
                                         unsigned int timing)
 {
        struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
-       u32 mode, tmp;
+       u32 mode;
 
        switch (timing) {
        case MMC_TIMING_MMC_HS:
@@ -125,18 +146,17 @@ static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
                mode = SDHCI_CDNS_HRS06_MODE_MMC_HS200;
                break;
        case MMC_TIMING_MMC_HS400:
-               mode = SDHCI_CDNS_HRS06_MODE_MMC_HS400;
+               if (priv->enhanced_strobe)
+                       mode = SDHCI_CDNS_HRS06_MODE_MMC_HS400ES;
+               else
+                       mode = SDHCI_CDNS_HRS06_MODE_MMC_HS400;
                break;
        default:
                mode = SDHCI_CDNS_HRS06_MODE_SD;
                break;
        }
 
-       /* The speed mode for eMMC is selected by HRS06 register */
-       tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
-       tmp &= ~SDHCI_CDNS_HRS06_MODE_MASK;
-       tmp |= mode;
-       writel(tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
+       sdhci_cdns_set_emmc_mode(priv, mode);
 
        /* For SD, fall back to the default handler */
        if (mode == SDHCI_CDNS_HRS06_MODE_SD)
@@ -213,6 +233,26 @@ static int sdhci_cdns_execute_tuning(struct mmc_host *mmc, u32 opcode)
        return sdhci_cdns_set_tune_val(host, end_of_streak - max_streak / 2);
 }
 
+static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
+                                            struct mmc_ios *ios)
+{
+       struct sdhci_host *host = mmc_priv(mmc);
+       struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+       u32 mode;
+
+       priv->enhanced_strobe = ios->enhanced_strobe;
+
+       mode = sdhci_cdns_get_emmc_mode(priv);
+
+       if (mode == SDHCI_CDNS_HRS06_MODE_MMC_HS400 && ios->enhanced_strobe)
+               sdhci_cdns_set_emmc_mode(priv,
+                                        SDHCI_CDNS_HRS06_MODE_MMC_HS400ES);
+
+       if (mode == SDHCI_CDNS_HRS06_MODE_MMC_HS400ES && !ios->enhanced_strobe)
+               sdhci_cdns_set_emmc_mode(priv,
+                                        SDHCI_CDNS_HRS06_MODE_MMC_HS400);
+}
+
 static int sdhci_cdns_probe(struct platform_device *pdev)
 {
        struct sdhci_host *host;
@@ -240,8 +280,11 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
 
        priv = sdhci_cdns_priv(host);
        priv->hrs_addr = host->ioaddr;
+       priv->enhanced_strobe = false;
        host->ioaddr += SDHCI_CDNS_SRS_BASE;
        host->mmc_host_ops.execute_tuning = sdhci_cdns_execute_tuning;
+       host->mmc_host_ops.hs400_enhanced_strobe =
+                               sdhci_cdns_hs400_enhanced_strobe;
 
        ret = mmc_of_parse(host->mmc);
        if (ret)