[PATCH V3 1/2] mmc: core: Add host specific tuning support for SD HS mode

[Wenchao Chen <wenchao.chen@xxxxxxxxxx>]

Added .prepare_hs_tuning and .execute_hs_tuning host callbacks to
support host-specific tuning for SD high speed mode. Howerver, these
callbacks are optional, host specific - and that there is nothing
in the SD spec that mentions this.

Signed-off-by: Wenchao Chen <wenchao.chen@xxxxxxxxxx>
---
 drivers/mmc/core/sd.c     | 14 ++++++++++++++
 drivers/mmc/core/sd_ops.c |  1 +
 include/linux/mmc/host.h  |  8 ++++++++
 3 files changed, 23 insertions(+)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 246ce027ae0a..c3e554344c99 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1518,6 +1518,13 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 		 */
 		mmc_set_clock(host, mmc_sd_get_max_clock(card));
 
+		if (host->ios.timing == MMC_TIMING_SD_HS &&
+			host->ops->prepare_sd_hs_tuning) {
+			err = host->ops->prepare_sd_hs_tuning(host, card);
+			if (err)
+				goto free_card;
+		}
+
 		/*
 		 * Switch to wider bus (if supported).
 		 */
@@ -1529,6 +1536,13 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 
 			mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
 		}
+
+		if (host->ios.timing == MMC_TIMING_SD_HS &&
+			host->ops->execute_sd_hs_tuning) {
+			err = host->ops->execute_sd_hs_tuning(host, card);
+			if (err)
+				goto free_card;
+		}
 	}
 cont:
 	if (!oldcard) {
diff --git a/drivers/mmc/core/sd_ops.c b/drivers/mmc/core/sd_ops.c
index ef8d1dce5af1..a59cd592f06e 100644
--- a/drivers/mmc/core/sd_ops.c
+++ b/drivers/mmc/core/sd_ops.c
@@ -323,6 +323,7 @@ int mmc_sd_switch(struct mmc_card *card, int mode, int group,
 	return mmc_send_adtc_data(card, card->host, SD_SWITCH, cmd_args, resp,
 				  64);
 }
+EXPORT_SYMBOL_GPL(mmc_sd_switch);
 
 int mmc_app_sd_status(struct mmc_card *card, void *ssr)
 {
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 461d1543893b..62a6847a3b6f 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -184,6 +184,12 @@ struct mmc_host_ops {
 	/* Execute HS400 tuning depending host driver */
 	int	(*execute_hs400_tuning)(struct mmc_host *host, struct mmc_card *card);
 
+	/* Optional callback to prepare for SD high-speed tuning */
+	int	(*prepare_sd_hs_tuning)(struct mmc_host *host, struct mmc_card *card);
+
+	/* Optional callback to execute SD high-speed tuning */
+	int	(*execute_sd_hs_tuning)(struct mmc_host *host, struct mmc_card *card);
+
 	/* Prepare switch to DDR during the HS400 init sequence */
 	int	(*hs400_prepare_ddr)(struct mmc_host *host);
 
@@ -665,6 +671,8 @@ static inline void mmc_debugfs_err_stats_inc(struct mmc_host *host,
 	host->err_stats[stat] += 1;
 }
 
+int mmc_sd_switch(struct mmc_card *card, int mode, int group, u8 value, u8 *resp);
+int mmc_send_status(struct mmc_card *card, u32 *status);
 int mmc_send_tuning(struct mmc_host *host, u32 opcode, int *cmd_error);
 int mmc_send_abort_tuning(struct mmc_host *host, u32 opcode);
 int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd);
-- 
2.17.1