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>

6 files changed, 118 insertions, 6 deletions

diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index f37e9d6af84a..d2dbf02022bd 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -349,6 +349,7 @@ 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 1f730dbfaeea..91eb16223246 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 bec6786efd19..793c6f7ddb04 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;
 
@@ -768,7 +785,9 @@ static int __mmc_select_powerclass(struct mmc_card *card,
                                 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 @@ static void mmc_set_bus_speed(struct mmc_card *card)
 {
         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 @@ static int mmc_select_hs_ddr(struct mmc_card *card)
         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 @@ 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)
 {
         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 @@ 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);
+                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 176073692872..d424b9de3aff 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 6b1e9ee6ca10..183087374215 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -61,6 +61,7 @@ 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
 
         unsigned char   signal_voltage;         /* signalling voltage (1.8V or 3.3V) */
 
@@ -132,6 +133,9 @@ struct mmc_host_ops {
 
         /* The tuning command opcode value is different for SD and eMMC cards */
         int     (*execute_tuning)(struct mmc_host *host, u32 opcode);
+
+        /* Prepare HS400 target operating frequency depending host driver */
+        int     (*prepare_hs400_tuning)(struct mmc_host *host, struct mmc_ios *ios);
         int     (*select_drive_strength)(unsigned int max_dtr, int host_drv, int card_drv);
         void    (*hw_reset)(struct mmc_host *host);
         void    (*card_event)(struct mmc_host *host);
@@ -274,6 +278,10 @@ struct mmc_host {
 #define MMC_CAP2_PACKED_CMD     (MMC_CAP2_PACKED_RD | \
                                  MMC_CAP2_PACKED_WR)
 #define MMC_CAP2_NO_PRESCAN_POWERUP (1 << 14)   /* Don't power up before scan */
+#define MMC_CAP2_HS400_1_8V     (1 << 15)       /* Can support HS400 1.8V */
+#define MMC_CAP2_HS400_1_2V     (1 << 16)       /* 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 */
 
@@ -495,4 +503,10 @@ static inline bool mmc_card_ddr52(struct mmc_card *card)
 {
         return card->host->ios.timing == MMC_TIMING_MMC_DDR52;
 }
+
+static inline bool mmc_card_hs400(struct mmc_card *card)
+{
+        return card->host->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 f429f13be433..64ec963ed347 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)