[PATCH 2/2] mmc: dw_mmc: add hw_reset extension hook

[Shawn Lin <shawn.lin@rock-chips.com>]

This patch add hw_reset for dw_mmc to implement hw reset
procedure. It's useful for mmc core to recover emmc devices
if emmc runs into unexpected state. Add MMC_CAP_HW_RESET
capability to dw_mmc extension driver directly if it needs hw_reset.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---

 drivers/mmc/host/dw_mmc.c | 4 ++++
 drivers/mmc/host/dw_mmc.h | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 8a0f2995..46b12de 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1482,6 +1482,10 @@ 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;
+
+	if (drv_data && drv_data->hw_reset)
+		return drv_data->hw_reset(host);
 
 	if (host->use_dma == TRANS_MODE_IDMAC)
 		dw_mci_idmac_reset(host);
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 9df18c1..21b9df4 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -282,6 +282,7 @@ struct dw_mci_slot {
  * @set_ios: handle bus specific extensions.
  * @parse_dt: parse implementation specific device tree properties.
  * @execute_tuning: implementation specific tuning procedure.
+ * @hw_reset: implementation specific hw reset procedure.
  *
  * Provide controller implementation specific extensions. The usage of this
  * data structure is fully optional and usage of each member in this structure
@@ -299,5 +300,6 @@ struct dw_mci_drv_data {
 						struct mmc_ios *ios);
 	int		(*switch_voltage)(struct mmc_host *mmc,
 					  struct mmc_ios *ios);
+	void		(*hw_reset)(struct dw_mci *host);
 };
 #endif /* _DW_MMC_H_ */
-- 
2.3.7