When the device is non removable, the card detect signal is often use
for another purpose i.e. muxed to another SoC peripheral or used as a
GPIO. It could lead to wrong behaviors depending the defaut value of
this signal if not muxed to the SDHCI controller.
Fixes: bb5f8ea4d514 ("mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC")
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
---
drivers/mmc/host/sdhci-of-at91.c | 36 +++++++++++++++++++++++++++++++++++-
1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
index 88e9b5f35a62..6a389f35396e 100644
--- a/drivers/mmc/host/sdhci-of-at91.c
+++ b/drivers/mmc/host/sdhci-of-at91.c
@@ -31,6 +31,7 @@
#define SDMMC_MC1R 0x204
#define SDMMC_MC1R_DDR BIT(3)
+#define SDMMC_MC1R_FCD BIT(7)
#define SDMMC_CACR 0x230
#define SDMMC_CACR_CAPWREN BIT(0)
#define SDMMC_CACR_KEY (0x46 << 8)
@@ -44,6 +45,15 @@ struct sdhci_at91_priv {
bool restore_needed;
};
+static void sdhci_at91_set_force_card_detect(struct sdhci_host *host)
+{
+ u8 mc1r;
+
+ mc1r = readb(host->ioaddr + SDMMC_MC1R);
+ mc1r |= SDMMC_MC1R_FCD;
+ writeb(mc1r, host->ioaddr + SDMMC_MC1R);
+}
+
static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
{
u16 clk;
@@ -111,10 +121,18 @@ void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
sdhci_set_uhs_signaling(host, timing);
}
+static void sdhci_at91_reset(struct sdhci_host *host, u8 mask)
+{
+ sdhci_reset(host, mask);
+
+ if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
+ sdhci_at91_set_force_card_detect(host);
+}
+
static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
.set_clock = sdhci_at91_set_clock,
.set_bus_width = sdhci_set_bus_width,
- .reset = sdhci_reset,
+ .reset = sdhci_at91_reset,
.set_uhs_signaling = sdhci_at91_set_uhs_signaling,
.set_power = sdhci_at91_set_power,
};
@@ -369,6 +387,22 @@ static int sdhci_at91_probe(struct platform_device *pdev)
host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
}
+ /*
+ * If the device attached to the MMC bus is not removable, it is safer
+ * to set the Force Card Detect bit. People often don't connect the
+ * card detect signal and use this pin for another purpose. If the card
+ * detect pin is not muxed to SDHCI controller, a default value is
+ * used. This value can be different from a SoC revision to another
+ * one. Problems come when this default value is not card present. To
+ * avoid this case, if the device is non removable then the card
+ * detection procedure using the SDMCC_CD signal is bypassed.
+ * This bit is resetted when a software reset for all command is
+ * performed so we need to implement our own reset function to set back
+ * this bit.
+ */
+ if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
+ sdhci_at91_set_force_card_detect(host);
+
pm_runtime_put_autosuspend(&pdev->dev);
return 0;
--
2.12.2
--
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