mmc: sdhci-esdhc-imx: reset tuning circuit when power on mmc card

USDHC tuning circuit should be reset before every time card enumeration
or re-enumeration.

SD3.0 card need tuning. For SDR104 card, when system suspend in standby
mode, and then resume back, the IO timing is still SDR104(tuned) which
may result in card re-enumeration fail in low card speed(400khz) for some
cards. And we did meet the issue that in certain probability, SDR104
card meet mmc command CRC/Timeout error when send CMD2 during mmc bus
resume.

This patch reset the tuning circuit when the ios timing is
MMC_TIMING_LEGACY/MMC_TIMING_MMC_HS/MMC_TIMING_SD_HS, which means both
mmc_power_up() and mmc_power_off() will reset the tuning circuit.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Dong Aisheng <aisheng.dong@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index abad67a..23d8b8a 100644 (file)
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -889,6 +889,28 @@ static void esdhc_set_strobe_dll(struct sdhci_host *host)
        }
 }
 
+static void esdhc_reset_tuning(struct sdhci_host *host)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
+       u32 ctrl;
+
+       /* Rest the tuning circurt */
+       if (esdhc_is_usdhc(imx_data)) {
+               if (imx_data->socdata->flags & ESDHC_FLAG_MAN_TUNING) {
+                       ctrl = readl(host->ioaddr + ESDHC_MIX_CTRL);
+                       ctrl &= ~ESDHC_MIX_CTRL_SMPCLK_SEL;
+                       ctrl &= ~ESDHC_MIX_CTRL_FBCLK_SEL;
+                       writel(ctrl, host->ioaddr + ESDHC_MIX_CTRL);
+                       writel(0, host->ioaddr + ESDHC_TUNE_CTRL_STATUS);
+               } else if (imx_data->socdata->flags & ESDHC_FLAG_STD_TUNING) {
+                       ctrl = readl(host->ioaddr + SDHCI_ACMD12_ERR);
+                       ctrl &= ~ESDHC_MIX_CTRL_SMPCLK_SEL;
+                       writel(ctrl, host->ioaddr + SDHCI_ACMD12_ERR);
+               }
+       }
+}
+
 static void esdhc_set_uhs_signaling(struct sdhci_host *host, unsigned timing)
 {
        u32 m;
@@ -932,6 +954,10 @@ static void esdhc_set_uhs_signaling(struct sdhci_host *host, unsigned timing)
                host->ops->set_clock(host, host->clock);
                esdhc_set_strobe_dll(host);
                break;
+       case MMC_TIMING_LEGACY:
+       default:
+               esdhc_reset_tuning(host);
+               break;
        }
 
        esdhc_change_pinstate(host, timing);