mmc: sdhci-pci: 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-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
index cc851b065d0ae685d5297f7e4b8ac7a40b3e3465..df3b8eced8c4a50a727774404a066086d4ebe0f7 100644 (file)
--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c
@@ -330,6 +330,33 @@ static void spt_read_drive_strength(struct sdhci_host *host)
        sdhci_pci_spt_drive_strength = 0x10 | ((val >> 12) & 0xf);
 }
 
+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 byt_emmc_probe_slot(struct sdhci_pci_slot *slot)
 {
        slot->host->mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE |
@@ -362,6 +389,10 @@ static int byt_sd_probe_slot(struct sdhci_pci_slot *slot)
        slot->cd_con_id = NULL;
        slot->cd_idx = 0;
        slot->cd_override_level = true;
+       if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BXT_SD ||
+           slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_APL_SD)
+               slot->host->mmc_host_ops.get_cd = bxt_get_cd;
+
        return 0;
 }