mmc: sdhci: add eMMC hardware reset support

Add an SDHCI operation for hardware reset and connect it to the
host controller operation.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/sdhci.c

@@ -1471,6 +1471,14 @@ static int sdhci_get_ro(struct mmc_host *mmc)
 	return 0;
 }
 
+static void sdhci_hw_reset(struct mmc_host *mmc)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+
+	if (host->ops && host->ops->hw_reset)
+		host->ops->hw_reset(host);
+}
+
 static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable)
 {
 	struct sdhci_host *host;
@@ -1805,6 +1813,7 @@ static const struct mmc_host_ops sdhci_ops = {
 	.request	= sdhci_request,
 	.set_ios	= sdhci_set_ios,
 	.get_ro		= sdhci_get_ro,
+	.hw_reset	= sdhci_hw_reset,
 	.enable_sdio_irq = sdhci_enable_sdio_irq,
 	.start_signal_voltage_switch	= sdhci_start_signal_voltage_switch,
 	.execute_tuning			= sdhci_execute_tuning,

drivers/mmc/host/sdhci.h

@@ -273,7 +273,7 @@ struct sdhci_ops {
 	void	(*platform_reset_enter)(struct sdhci_host *host, u8 mask);
 	void	(*platform_reset_exit)(struct sdhci_host *host, u8 mask);
 	int	(*set_uhs_signaling)(struct sdhci_host *host, unsigned int uhs);
-
+	void	(*hw_reset)(struct sdhci_host *host);
 };
 
 #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS