mmc: sdhci-of-esdhc: workaround for unreliable pulse width detection

This was a SoC issue on LX2160A Rev1.0.
eSDHC_DLLCFG1[DLL_PD_PULSE_STRETCH_SEL] must be set to 0 to
get 4 delay cells in the pulse width detection logic for eMMC
HS400 mode. Otherwise it would cause unexpected HS400 issue.
This patch is to clear this bit always for affected SoC when
reset for all, since this bit doesn't affect other speed modes.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci-esdhc.h b/drivers/mmc/host/sdhci-esdhc.h
index 721a635b10e723442cadcf48bb7d1438a4b61e74..39dbbd6eaf28fbca906ef2bf984de40031397334 100644 (file)
--- a/drivers/mmc/host/sdhci-esdhc.h
+++ b/drivers/mmc/host/sdhci-esdhc.h
@@ -78,6 +78,10 @@
 #define ESDHC_DLL_ENABLE               0x80000000
 #define ESDHC_DLL_FREQ_SEL             0x08000000
 
+/* DLL Config 1 Register */
+#define ESDHC_DLLCFG1                  0x164
+#define ESDHC_DLL_PD_PULSE_STRETCH_SEL 0x80000000
+
 /* DLL Status 0 Register */
 #define ESDHC_DLLSTAT0                 0x170
 #define ESDHC_DLL_STS_SLV_LOCK         0x08000000

diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
index b93a4556ac8cada45144a148d88f5f4b74b2bd9f..856e809f38b7fe931be071da0abcdf0f9d4257cc 100644 (file)
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -79,6 +79,7 @@ struct sdhci_esdhc {
        u8 spec_ver;
        bool quirk_incorrect_hostver;
        bool quirk_limited_clk_division;
+       bool quirk_unreliable_pulse_detection;
        bool quirk_fixup_tuning;
        unsigned int peripheral_clock;
        const struct esdhc_clk_fixup *clk_fixup;
@@ -676,6 +677,8 @@ static void esdhc_pltfm_set_bus_width(struct sdhci_host *host, int width)
 
 static void esdhc_reset(struct sdhci_host *host, u8 mask)
 {
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct sdhci_esdhc *esdhc = sdhci_pltfm_priv(pltfm_host);
        u32 val;
 
        sdhci_reset(host, mask);
@@ -687,6 +690,12 @@ static void esdhc_reset(struct sdhci_host *host, u8 mask)
                val = sdhci_readl(host, ESDHC_TBCTL);
                val &= ~ESDHC_TB_EN;
                sdhci_writel(host, val, ESDHC_TBCTL);
+
+               if (esdhc->quirk_unreliable_pulse_detection) {
+                       val = sdhci_readl(host, ESDHC_DLLCFG1);
+                       val &= ~ESDHC_DLL_PD_PULSE_STRETCH_SEL;
+                       sdhci_writel(host, val, ESDHC_DLLCFG1);
+               }
        }
 }
 
@@ -941,6 +950,11 @@ static struct soc_device_attribute soc_fixup_sdhc_clkdivs[] = {
        { },
 };
 
+static struct soc_device_attribute soc_unreliable_pulse_detection[] = {
+       { .family = "QorIQ LX2160A", .revision = "1.0", },
+       { },
+};
+
 static void esdhc_init(struct platform_device *pdev, struct sdhci_host *host)
 {
        const struct of_device_id *match;
@@ -968,6 +982,11 @@ static void esdhc_init(struct platform_device *pdev, struct sdhci_host *host)
        else
                esdhc->quirk_limited_clk_division = false;
 
+       if (soc_device_match(soc_unreliable_pulse_detection))
+               esdhc->quirk_unreliable_pulse_detection = true;
+       else
+               esdhc->quirk_unreliable_pulse_detection = false;
+
        match = of_match_node(sdhci_esdhc_of_match, pdev->dev.of_node);
        if (match)
                esdhc->clk_fixup = match->data;