[PATCH 5/5] mmc: add support for HS400 mode of eMMC5.0

[Seungwon Jeon <tgih.jun@samsung.com>]

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>
---
 drivers/mmc/core/bus.c     |    1 +
 drivers/mmc/core/debugfs.c |    3 +
 drivers/mmc/core/mmc.c     |  126 +++++++++++++++++++++++++++++++++++++++++---
 include/linux/mmc/card.h   |    1 +
 include/linux/mmc/host.h   |   15 +++++-
 include/linux/mmc/mmc.h    |    7 ++-
 6 files changed, 144 insertions(+), 9 deletions(-)

diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index e8a21fb..d28ecf1 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -358,6 +358,7 @@ int mmc_add_card(struct mmc_card *card)
 			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 @@ static int mmc_ios_show(struct seq_file *s, void *data)
 	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 6ce5ff3..f3c899d 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -240,7 +240,7 @@ static int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd)
 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 @@ static void mmc_select_card_type(struct mmc_card *card)
 		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 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 			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 @@ static int mmc_compare_ext_csds(struct mmc_card *card, unsigned bus_width)
 		(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;
 
@@ -729,7 +746,8 @@ static struct device_type mmc_type = {
 
 static inline unsigned int mmc_snoop_ddr(struct mmc_card *card)
 {
-	return card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_52;
+	return card->mmc_avail_type &
+		(EXT_CSD_CARD_TYPE_DDR_52 | EXT_CSD_CARD_TYPE_HS400);
 }
 
 /*
@@ -785,7 +803,9 @@ static int __mmc_select_powerclass(struct mmc_card *card,
 				card->ext_csd.raw_pwr_cl_52_360 :
 				card->ext_csd.raw_pwr_cl_ddr_52_360;
 		else if (host->ios.clock <= MMC_HS200_MAX_DTR)
-			pwrclass_val = card->ext_csd.raw_pwr_cl_200_360;
+			pwrclass_val = (bus_width == EXT_CSD_DDR_BUS_WIDTH_8) ?
+				card->ext_csd.raw_pwr_cl_ddr_200_360 :
+				card->ext_csd.raw_pwr_cl_200_360;
 		break;
 	default:
 		pr_warning("%s: Voltage range not supported "
@@ -858,7 +878,8 @@ static void mmc_set_bus_speed(struct mmc_card *card)
 
 	BUG_ON(!card);
 
-	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;
@@ -962,6 +983,30 @@ static int mmc_select_hs(struct mmc_card *card)
 }
 
 /*
+ * Revert to the high-speed mode from above speed
+ */
+static int mmc_revert_to_hs(struct mmc_card *card)
+{
+	BUG_ON(!card);
+
+	/*
+	 * CMD13, which is used to confirm the completion of timing
+	 * change, will be issued at higher speed timing condtion
+	 * rather than high-speed. If device has completed the change
+	 * to high-speed mode, it may not be proper timing to issue
+	 * command. Low speed supplies better timing margin than high
+	 * speed. Accordingly clock rate & timging should be chagned
+	 * ahead before actual switch.
+	 */
+	mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
+	mmc_set_bus_speed(card);
+
+	return mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			  EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
+			  card->ext_csd.generic_cmd6_time);
+}
+
+/*
  * Activate wide bus and DDR if supported.
  */
 static int mmc_select_hs_ddr(struct mmc_card *card, u8 *ext_csd)
@@ -1020,6 +1065,60 @@ static int mmc_select_hs_ddr(struct mmc_card *card, u8 *ext_csd)
 	return err;
 }
 
+static int mmc_select_hs400(struct mmc_card *card, u8 *ext_csd)
+{
+	struct mmc_host *host;
+	int err = 0, ddr;
+
+	BUG_ON(!card);
+
+	host = card->host;
+
+	ddr = mmc_snoop_ddr(card);
+
+	/*
+	 * The bus width is set to only 8 DDR in HS400 mode
+	 */
+	if (!(ddr & EXT_CSD_CARD_TYPE_HS400 &&
+	      card->host->ios.bus_width == MMC_BUS_WIDTH_8))
+		return 0;
+
+	/*
+	 * Before setting BUS_WIDTH for dual data rate operation,
+	 * HS_TIMING must be set to High Speed(0x1)
+	 */
+	err = mmc_revert_to_hs(card);
+	if (err) {
+		pr_warn("%s: switch to high-speed from hs200 failed, err:%d\n",
+			mmc_hostname(card->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(card->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);
+	if (err) {
+		pr_warn("%s: switch to hs400 failed, err:%d\n",
+			 mmc_hostname(card->host), err);
+		return err;
+	}
+
+	mmc_set_timing(card->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.
@@ -1055,7 +1154,16 @@ static int mmc_select_hs200(struct mmc_card *card)
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				 EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS200,
 				 card->ext_csd.generic_cmd6_time);
-		if (!err)
+		if (err)
+			goto err;
+
+		if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400)
+			/*
+			 * Timing should be adjusted to the HS400 target
+			 * operation frequency for tuning process
+			 */
+			mmc_set_timing(host, MMC_TIMING_MMC_HS400_TUNING);
+		else
 			mmc_set_timing(host, MMC_TIMING_MMC_HS200);
 	}
 err:
@@ -1105,7 +1213,7 @@ bus_speed:
 
 /*
  * 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)
 {
@@ -1343,6 +1451,10 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		err = mmc_hs200_tuning(card);
 		if (err)
 			goto err;
+
+		err = mmc_select_hs400(card, ext_csd);
+		if (err)
+			goto err;
 	} else if (mmc_card_hs(card)) {
 		/* Select the desired bus width optionally */
 		err = mmc_select_bus_width(card);
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index c278241..eabddfb 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -110,6 +110,7 @@ struct mmc_ext_csd {
 	u8			raw_pwr_cl_200_360;	/* 237 */
 	u8			raw_pwr_cl_ddr_52_195;	/* 238 */
 	u8			raw_pwr_cl_ddr_52_360;	/* 239 */
+	u8			raw_pwr_cl_ddr_200_360;	/* 253 */
 	u8			raw_bkops_status;	/* 246 */
 	u8			raw_sectors[4];		/* 212 - 4 bytes */
 
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 66e632c..7c0e277 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -61,6 +61,8 @@ struct mmc_ios {
 #define MMC_TIMING_UHS_DDR50	7
 #define MMC_TIMING_MMC_DDR52	8
 #define MMC_TIMING_MMC_HS200	9
+#define MMC_TIMING_MMC_HS400	10
+#define MMC_TIMING_MMC_HS400_TUNING 11
 
 	unsigned char	signal_voltage;		/* signalling voltage (1.8V or 3.3V) */
 
@@ -278,6 +280,10 @@ struct mmc_host {
 				 MMC_CAP2_PACKED_WR)
 #define MMC_CAP2_NO_PRESCAN_POWERUP (1 << 14)	/* Don't power up before scan */
 #define MMC_CAP2_SANITIZE	(1 << 15)		/* Support Sanitize */
+#define MMC_CAP2_HS400_1_8V	(1 << 16)	/* Can support HS400 1.8V */
+#define MMC_CAP2_HS400_1_2V	(1 << 17)	/* Can support HS400 1.2V */
+#define MMC_CAP2_HS400		(MMC_CAP2_HS400_1_8V | \
+				 MMC_CAP2_HS400_1_2V)
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 
@@ -495,11 +501,18 @@ static inline int mmc_card_uhs(struct mmc_card *card)
 
 static inline bool mmc_card_hs200(struct mmc_card *card)
 {
-	return card->ios->timing == MMC_TIMING_MMC_HS200;
+	return card->ios->timing == MMC_TIMING_MMC_HS200 ||
+		card->ios->timing == MMC_TIMING_MMC_HS400_TUNING;
 }
 
 static inline bool mmc_card_ddr52(struct mmc_card *card)
 {
 	return card->ios->timing == MMC_TIMING_MMC_DDR52;
 }
+
+static inline bool mmc_card_hs400(struct mmc_card *card)
+{
+	return card->ios->timing == MMC_TIMING_MMC_HS400;
+}
+
 #endif /* LINUX_MMC_HOST_H */
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index f429f13..64ec963 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -325,6 +325,7 @@ struct _mmc_csd {
 #define EXT_CSD_POWER_OFF_LONG_TIME	247	/* RO */
 #define EXT_CSD_GENERIC_CMD6_TIME	248	/* RO */
 #define EXT_CSD_CACHE_SIZE		249	/* RO, 4 bytes */
+#define EXT_CSD_PWR_CL_DDR_200_360	253	/* RO */
 #define EXT_CSD_TAG_UNIT_SIZE		498	/* RO */
 #define EXT_CSD_DATA_TAG_SUPPORT	499	/* RO */
 #define EXT_CSD_MAX_PACKED_WRITES	500	/* RO */
@@ -354,7 +355,6 @@ struct _mmc_csd {
 #define EXT_CSD_CMD_SET_SECURE		(1<<1)
 #define EXT_CSD_CMD_SET_CPSECURE	(1<<2)
 
-#define EXT_CSD_CARD_TYPE_MASK	0x3F	/* Mask out reserved bits */
 #define EXT_CSD_CARD_TYPE_HS_26	(1<<0)	/* Card can run at 26MHz */
 #define EXT_CSD_CARD_TYPE_HS_52	(1<<1)	/* Card can run at 52MHz */
 #define EXT_CSD_CARD_TYPE_HS	(EXT_CSD_CARD_TYPE_HS_26 | \
@@ -370,6 +370,10 @@ struct _mmc_csd {
 						/* SDR mode @1.2V I/O */
 #define EXT_CSD_CARD_TYPE_HS200		(EXT_CSD_CARD_TYPE_HS200_1_8V | \
 					 EXT_CSD_CARD_TYPE_HS200_1_2V)
+#define EXT_CSD_CARD_TYPE_HS400_1_8V	(1<<6)	/* Card can run at 200MHz DDR, 1.8V */
+#define EXT_CSD_CARD_TYPE_HS400_1_2V	(1<<7)	/* Card can run at 200MHz DDR, 1.2V */
+#define EXT_CSD_CARD_TYPE_HS400		(EXT_CSD_CARD_TYPE_HS400_1_8V | \
+					 EXT_CSD_CARD_TYPE_HS400_1_2V)
 
 #define EXT_CSD_BUS_WIDTH_1	0	/* Card is in 1 bit mode */
 #define EXT_CSD_BUS_WIDTH_4	1	/* Card is in 4 bit mode */
@@ -380,6 +384,7 @@ struct _mmc_csd {
 #define EXT_CSD_TIMING_BC	0	/* Backwards compatility */
 #define EXT_CSD_TIMING_HS	1	/* High speed */
 #define EXT_CSD_TIMING_HS200	2	/* HS200 */
+#define EXT_CSD_TIMING_HS400	3	/* HS400 */
 
 #define EXT_CSD_SEC_ER_EN	BIT(0)
 #define EXT_CSD_SEC_BD_BLK_EN	BIT(2)
-- 
1.7.0.4