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@xxxxxxx>
---
drivers/mmc/host/sdhci-esdhc-imx.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index abad67a..8960833 100644
--- 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);
+ u16 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 << 8, 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);
--
1.9.1
--
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