mmc: sdhci-pci: add support for eMMC hardware reset for BYT eMMC.

Add support for eMMC hardware reset for BYT eMMC.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/drivers/mmc/host/sdhci-pci.c b/drivers/mmc/host/sdhci-pci.c
index 611331a39fe51dd799762db4cceaf108dd1bacc9..e082fac6bc96b5569a9294afcffac44040d08fa0 100644 (file)
--- a/drivers/mmc/host/sdhci-pci.c
+++ b/drivers/mmc/host/sdhci-pci.c
@@ -77,6 +77,8 @@ struct sdhci_pci_slot {
        int                     rst_n_gpio;
        int                     cd_gpio;
        int                     cd_irq;
+
+       void (*hw_reset)(struct sdhci_host *host);
 };
 
 struct sdhci_pci_chip {
@@ -307,10 +309,27 @@ static const struct sdhci_pci_fixes sdhci_intel_pch_sdio = {
        .probe_slot     = pch_hc_probe_slot,
 };
 
+static void sdhci_pci_int_hw_reset(struct sdhci_host *host)
+{
+       u8 reg;
+
+       reg = sdhci_readb(host, SDHCI_POWER_CONTROL);
+       reg |= 0x10;
+       sdhci_writeb(host, reg, SDHCI_POWER_CONTROL);
+       /* For eMMC, minimum is 1us but give it 9us for good measure */
+       udelay(9);
+       reg &= ~0x10;
+       sdhci_writeb(host, reg, SDHCI_POWER_CONTROL);
+       /* For eMMC, minimum is 200us but give it 300us for good measure */
+       usleep_range(300, 1000);
+}
+
 static int byt_emmc_probe_slot(struct sdhci_pci_slot *slot)
 {
-       slot->host->mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE;
+       slot->host->mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE |
+                                MMC_CAP_HW_RESET;
        slot->host->mmc->caps2 |= MMC_CAP2_HC_ERASE_SZ;
+       slot->hw_reset = sdhci_pci_int_hw_reset;
        return 0;
 }
 
@@ -1016,7 +1035,7 @@ static int sdhci_pci_bus_width(struct sdhci_host *host, int width)
        return 0;
 }
 
-static void sdhci_pci_hw_reset(struct sdhci_host *host)
+static void sdhci_pci_gpio_hw_reset(struct sdhci_host *host)
 {
        struct sdhci_pci_slot *slot = sdhci_priv(host);
        int rst_n_gpio = slot->rst_n_gpio;
@@ -1031,6 +1050,14 @@ static void sdhci_pci_hw_reset(struct sdhci_host *host)
        usleep_range(300, 1000);
 }
 
+static void sdhci_pci_hw_reset(struct sdhci_host *host)
+{
+       struct sdhci_pci_slot *slot = sdhci_priv(host);
+
+       if (slot->hw_reset)
+               slot->hw_reset(host);
+}
+
 static const struct sdhci_ops sdhci_pci_ops = {
        .enable_dma     = sdhci_pci_enable_dma,
        .platform_bus_width     = sdhci_pci_bus_width,
@@ -1328,6 +1355,7 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot(
                if (!gpio_request(slot->rst_n_gpio, "eMMC_reset")) {
                        gpio_direction_output(slot->rst_n_gpio, 1);
                        slot->host->mmc->caps |= MMC_CAP_HW_RESET;
+                       slot->hw_reset = sdhci_pci_gpio_hw_reset;
                } else {
                        dev_warn(&pdev->dev, "failed to request rst_n_gpio\n");
                        slot->rst_n_gpio = -EINVAL;