mmc: add support for HS400 mode of eMMC5.0

This patch adds HS400 mode support for eMMC5.0 device.  HS400 mode is high
speed DDR interface timing from HS200.  Clock frequency is up to 200MHz
and only 8-bit bus width is supported. In addition, tuning process of
HS200 is required to synchronize the command response on the CMD line
because CMD input timing for HS400 mode is the same as HS200 mode.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed-by: Jackey Shen <jackey.shen@amd.com>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>
diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index f37e9d6..d2dbf02 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -349,6 +349,7 @@
 			mmc_hostname(card->host),
 			mmc_card_uhs(card) ? "ultra high speed " :
 			(mmc_card_hs(card) ? "high speed " : ""),
+			mmc_card_hs400(card) ? "HS400 " :
 			(mmc_card_hs200(card) ? "HS200 " : ""),
 			mmc_card_ddr52(card) ? "DDR " : "",
 			uhs_bus_speed_mode, type, card->rca);
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 1f730db..91eb162 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -141,6 +141,9 @@
 	case MMC_TIMING_MMC_HS200:
 		str = "mmc HS200";
 		break;
+	case MMC_TIMING_MMC_HS400:
+		str = "mmc HS400";
+		break;
 	default:
 		str = "invalid";
 		break;
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index bec6786..793c6f7 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -240,7 +240,7 @@
 static void mmc_select_card_type(struct mmc_card *card)
 {
 	struct mmc_host *host = card->host;
-	u8 card_type = card->ext_csd.raw_card_type & EXT_CSD_CARD_TYPE_MASK;
+	u8 card_type = card->ext_csd.raw_card_type;
 	u32 caps = host->caps, caps2 = host->caps2;
 	unsigned int hs_max_dtr = 0, hs200_max_dtr = 0;
 	unsigned int avail_type = 0;
@@ -281,6 +281,18 @@
 		avail_type |= EXT_CSD_CARD_TYPE_HS200_1_2V;
 	}
 
+	if (caps2 & MMC_CAP2_HS400_1_8V &&
+	    card_type & EXT_CSD_CARD_TYPE_HS400_1_8V) {
+		hs200_max_dtr = MMC_HS200_MAX_DTR;
+		avail_type |= EXT_CSD_CARD_TYPE_HS400_1_8V;
+	}
+
+	if (caps2 & MMC_CAP2_HS400_1_2V &&
+	    card_type & EXT_CSD_CARD_TYPE_HS400_1_2V) {
+		hs200_max_dtr = MMC_HS200_MAX_DTR;
+		avail_type |= EXT_CSD_CARD_TYPE_HS400_1_2V;
+	}
+
 	card->ext_csd.hs_max_dtr = hs_max_dtr;
 	card->ext_csd.hs200_max_dtr = hs200_max_dtr;
 	card->mmc_avail_type = avail_type;
@@ -499,6 +511,8 @@
 			ext_csd[EXT_CSD_PWR_CL_DDR_52_195];
 		card->ext_csd.raw_pwr_cl_ddr_52_360 =
 			ext_csd[EXT_CSD_PWR_CL_DDR_52_360];
+		card->ext_csd.raw_pwr_cl_ddr_200_360 =
+			ext_csd[EXT_CSD_PWR_CL_DDR_200_360];
 	}
 
 	if (card->ext_csd.rev >= 5) {
@@ -665,7 +679,10 @@
 		(card->ext_csd.raw_pwr_cl_ddr_52_195 ==
 			bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_195]) &&
 		(card->ext_csd.raw_pwr_cl_ddr_52_360 ==
-			bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_360]));
+			bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_360]) &&
+		(card->ext_csd.raw_pwr_cl_ddr_200_360 ==
+			bw_ext_csd[EXT_CSD_PWR_CL_DDR_200_360]));
+
 	if (err)
 		err = -EINVAL;
 
@@ -768,7 +785,9 @@
 				ext_csd->raw_pwr_cl_52_360 :
 				ext_csd->raw_pwr_cl_ddr_52_360;
 		else if (host->ios.clock <= MMC_HS200_MAX_DTR)
-			pwrclass_val = ext_csd->raw_pwr_cl_200_360;
+			pwrclass_val = (bus_width == EXT_CSD_DDR_BUS_WIDTH_8) ?
+				ext_csd->raw_pwr_cl_ddr_200_360 :
+				ext_csd->raw_pwr_cl_200_360;
 		break;
 	default:
 		pr_warning("%s: Voltage range not supported "
@@ -832,7 +851,8 @@
 {
 	unsigned int max_dtr = (unsigned int)-1;
 
-	if (mmc_card_hs200(card) && max_dtr > card->ext_csd.hs200_max_dtr)
+	if ((mmc_card_hs200(card) || mmc_card_hs400(card)) &&
+	     max_dtr > card->ext_csd.hs200_max_dtr)
 		max_dtr = card->ext_csd.hs200_max_dtr;
 	else if (mmc_card_hs(card) && max_dtr > card->ext_csd.hs_max_dtr)
 		max_dtr = card->ext_csd.hs_max_dtr;
@@ -985,6 +1005,61 @@
 	return err;
 }
 
+static int mmc_select_hs400(struct mmc_card *card)
+{
+	struct mmc_host *host = card->host;
+	int err = 0;
+
+	/*
+	 * HS400 mode requires 8-bit bus width
+	 */
+	if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+	      host->ios.bus_width == MMC_BUS_WIDTH_8))
+		return 0;
+
+	/*
+	 * Before switching to dual data rate operation for HS400,
+	 * it is required to convert from HS200 mode to HS mode.
+	 */
+	mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
+	mmc_set_bus_speed(card);
+
+	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			   EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
+			   card->ext_csd.generic_cmd6_time,
+			   true, true, true);
+	if (err) {
+		pr_warn("%s: switch to high-speed from hs200 failed, err:%d\n",
+			mmc_hostname(host), err);
+		return err;
+	}
+
+	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			 EXT_CSD_BUS_WIDTH,
+			 EXT_CSD_DDR_BUS_WIDTH_8,
+			 card->ext_csd.generic_cmd6_time);
+	if (err) {
+		pr_warn("%s: switch to bus width for hs400 failed, err:%d\n",
+			mmc_hostname(host), err);
+		return err;
+	}
+
+	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			   EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS400,
+			   card->ext_csd.generic_cmd6_time,
+			   true, true, true);
+	if (err) {
+		pr_warn("%s: switch to hs400 failed, err:%d\n",
+			 mmc_hostname(host), err);
+		return err;
+	}
+
+	mmc_set_timing(host, MMC_TIMING_MMC_HS400);
+	mmc_set_bus_speed(card);
+
+	return 0;
+}
+
 /*
  * For device supporting HS200 mode, the following sequence
  * should be done before executing the tuning process.
@@ -1062,13 +1137,22 @@
 
 /*
  * Execute tuning sequence to seek the proper bus operating
- * conditions for HS200, which sends CMD21 to the device.
+ * conditions for HS200 and HS400, which sends CMD21 to the device.
  */
 static int mmc_hs200_tuning(struct mmc_card *card)
 {
 	struct mmc_host *host = card->host;
 	int err = 0;
 
+	/*
+	 * Timing should be adjusted to the HS400 target
+	 * operation frequency for tuning process
+	 */
+	if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+	    host->ios.bus_width == MMC_BUS_WIDTH_8)
+		if (host->ops->prepare_hs400_tuning)
+			host->ops->prepare_hs400_tuning(host, &host->ios);
+
 	if (host->ops->execute_tuning) {
 		mmc_host_clk_hold(host);
 		err = host->ops->execute_tuning(host,
@@ -1296,6 +1380,10 @@
 		err = mmc_hs200_tuning(card);
 		if (err)
 			goto err;
+
+		err = mmc_select_hs400(card);
+		if (err)
+			goto err;
 	} else if (mmc_card_hs(card)) {
 		/* Select the desired bus width optionally */
 		err = mmc_select_bus_width(card);