mmc: sdhci-acpi: Fix card detect race for Intel BXT/APL

Intel BXT/APL use a card detect GPIO however the host controller
will not enable bus power unless it's card detect also reflects
the presence of a card.  Unfortunately those 2 things race which
can result in commands not starting, after which the controller
does nothing and there is a 10 second wait for the driver's
10-second timer to timeout.

That is fixed by having the driver look also at the present state
register to determine if the card is present.  Consequently, provide
a 'get_cd' mmc host operation for BXT/APL that does that.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
index f6047fc9406204d6ee672b74544d0ec6866308cd..a5cda926d38eb23be20eece31c6b1ef0c44723a3 100644 (file)
--- a/drivers/mmc/host/sdhci-acpi.c
+++ b/drivers/mmc/host/sdhci-acpi.c
@@ -146,6 +146,33 @@ static const struct sdhci_acpi_chip sdhci_acpi_chip_int = {
        .ops = &sdhci_acpi_ops_int,
 };
 
+static int bxt_get_cd(struct mmc_host *mmc)
+{
+       int gpio_cd = mmc_gpio_get_cd(mmc);
+       struct sdhci_host *host = mmc_priv(mmc);
+       unsigned long flags;
+       int ret = 0;
+
+       if (!gpio_cd)
+               return 0;
+
+       pm_runtime_get_sync(mmc->parent);
+
+       spin_lock_irqsave(&host->lock, flags);
+
+       if (host->flags & SDHCI_DEVICE_DEAD)
+               goto out;
+
+       ret = !!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT);
+out:
+       spin_unlock_irqrestore(&host->lock, flags);
+
+       pm_runtime_mark_last_busy(mmc->parent);
+       pm_runtime_put_autosuspend(mmc->parent);
+
+       return ret;
+}
+
 static int sdhci_acpi_emmc_probe_slot(struct platform_device *pdev,
                                      const char *hid, const char *uid)
 {
@@ -196,6 +223,9 @@ static int sdhci_acpi_sd_probe_slot(struct platform_device *pdev,
 
        /* Platform specific code during sd probe slot goes here */
 
+       if (hid && !strcmp(hid, "80865ACA"))
+               host->mmc_host_ops.get_cd = bxt_get_cd;
+
        return 0;
 }