mmc: sdhci-acpi: add support for eMMC hardware reset for HID 80860F14

Add support for eMMC hardware reset for HID 80860F14.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/sdhci-acpi.c

@@ -37,6 +37,7 @@
 #include <linux/acpi_gpio.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/delay.h>
 
 #include <linux/mmc/host.h>
 #include <linux/mmc/pm.h>
@@ -85,12 +86,37 @@ static int sdhci_acpi_enable_dma(struct sdhci_host *host)
 	return 0;
 }
 
+static void sdhci_acpi_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 const struct sdhci_ops sdhci_acpi_ops_dflt = {
 	.enable_dma = sdhci_acpi_enable_dma,
 };
 
+static const struct sdhci_ops sdhci_acpi_ops_int = {
+	.enable_dma = sdhci_acpi_enable_dma,
+	.hw_reset   = sdhci_acpi_int_hw_reset,
+};
+
+static const struct sdhci_acpi_chip sdhci_acpi_chip_int = {
+	.ops = &sdhci_acpi_ops_int,
+};
+
 static const struct sdhci_acpi_slot sdhci_acpi_slot_int_emmc = {
-	.caps    = MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE,
+	.chip    = &sdhci_acpi_chip_int,
+	.caps    = MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE | MMC_CAP_HW_RESET,
 	.caps2   = MMC_CAP2_HC_ERASE_SZ,
 	.flags   = SDHCI_ACPI_RUNTIME_PM,
 };