mmc: dw_mmc: Add support for platform specific eMMC HW reset

This commit adds a new callback to allow drivers to support platform
specific eMMC HW reset.
Reviewed-by: David Thompson <davthompson@nvidia.com>
Signed-off-by: Liming Sun <limings@nvidia.com>
Link: https://lore.kernel.org/r/3df02ffa8bdaa74f5261c8914d2545b97fb3478a.1718213918.git.limings@nvidia.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc.c

@@ -1617,6 +1617,7 @@ static void dw_mci_hw_reset(struct mmc_host *mmc)
 {
 	struct dw_mci_slot *slot = mmc_priv(mmc);
 	struct dw_mci *host = slot->host;
+	const struct dw_mci_drv_data *drv_data = host->drv_data;
 	int reset;
 
 	if (host->use_dma == TRANS_MODE_IDMAC)
@@ -1626,6 +1627,11 @@ static void dw_mci_hw_reset(struct mmc_host *mmc)
 				     SDMMC_CTRL_FIFO_RESET))
 		return;
 
+	if (drv_data && drv_data->hw_reset) {
+		drv_data->hw_reset(host);
+		return;
+	}
+
 	/*
 	 * According to eMMC spec, card reset procedure:
 	 * tRstW >= 1us:   RST_n pulse width

drivers/mmc/host/dw_mmc.h

@@ -566,6 +566,7 @@ struct dw_mci_slot {
  * @execute_tuning: implementation specific tuning procedure.
  * @set_data_timeout: implementation specific timeout.
  * @get_drto_clks: implementation specific cycle count for data read timeout.
+ * @hw_reset: implementation specific HW reset.
  *
  * Provide controller implementation specific extensions. The usage of this
  * data structure is fully optional and usage of each member in this structure
@@ -586,5 +587,6 @@ struct dw_mci_drv_data {
 	void		(*set_data_timeout)(struct dw_mci *host,
 					  unsigned int timeout_ns);
 	u32		(*get_drto_clks)(struct dw_mci *host);
+	void		(*hw_reset)(struct dw_mci *host);
 };
 #endif /* _DW_MMC_H_ */