mmc: mmc: Add driver strength selection

Add the ability to set eMMC driver strength
for HS200 and HS400.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 9b808d1..e519e31 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1044,6 +1044,7 @@ static int mmc_select_hs400(struct mmc_card *card)
 {
        struct mmc_host *host = card->host;
        int err = 0;
+       u8 val;
 
        /*
         * HS400 mode requires 8-bit bus width
@@ -1059,8 +1060,10 @@ static int mmc_select_hs400(struct mmc_card *card)
        mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
        mmc_set_bus_speed(card);
 
+       val = EXT_CSD_TIMING_HS |
+             card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
        err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                          EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
+                          EXT_CSD_HS_TIMING, val,
                           card->ext_csd.generic_cmd6_time,
                           true, true, true);
        if (err) {
@@ -1079,8 +1082,10 @@ static int mmc_select_hs400(struct mmc_card *card)
                return err;
        }
 
+       val = EXT_CSD_TIMING_HS400 |
+             card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
        err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                          EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS400,
+                          EXT_CSD_HS_TIMING, val,
                           card->ext_csd.generic_cmd6_time,
                           true, true, true);
        if (err) {
@@ -1119,6 +1124,7 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
        bool send_status = true;
        unsigned int max_dtr;
        int err;
+       u8 val;
 
        if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
                send_status = false;
@@ -1128,8 +1134,10 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
        mmc_set_clock(host, max_dtr);
 
        /* Switch HS400 to HS DDR */
+       val = EXT_CSD_TIMING_HS |
+             card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
        err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
-                          EXT_CSD_TIMING_HS, card->ext_csd.generic_cmd6_time,
+                          val, card->ext_csd.generic_cmd6_time,
                           true, send_status, true);
        if (err)
                goto out_err;
@@ -1158,10 +1166,11 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
        }
 
        /* Switch HS to HS200 */
+       val = EXT_CSD_TIMING_HS200 |
+             card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
        err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
-                          EXT_CSD_TIMING_HS200,
-                          card->ext_csd.generic_cmd6_time, true, send_status,
-                          true);
+                          val, card->ext_csd.generic_cmd6_time, true,
+                          send_status, true);
        if (err)
                goto out_err;
 
@@ -1183,6 +1192,23 @@ out_err:
        return err;
 }
 
+static void mmc_select_driver_type(struct mmc_card *card)
+{
+       int card_drv_type, drive_strength, drv_type;
+
+       card_drv_type = card->ext_csd.raw_driver_strength |
+                       mmc_driver_type_mask(0);
+
+       drive_strength = mmc_select_drive_strength(card,
+                                                  card->ext_csd.hs200_max_dtr,
+                                                  card_drv_type, &drv_type);
+
+       card->drive_strength = drive_strength;
+
+       if (drv_type)
+               mmc_set_driver_type(card->host, drv_type);
+}
+
 /*
  * For device supporting HS200 mode, the following sequence
  * should be done before executing the tuning process.
@@ -1194,6 +1220,7 @@ static int mmc_select_hs200(struct mmc_card *card)
 {
        struct mmc_host *host = card->host;
        int err = -EINVAL;
+       u8 val;
 
        if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
                err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_120);
@@ -1205,14 +1232,18 @@ static int mmc_select_hs200(struct mmc_card *card)
        if (err)
                goto err;
 
+       mmc_select_driver_type(card);
+
        /*
         * Set the bus width(4 or 8) with host's support and
         * switch to HS200 mode if bus width is set successfully.
         */
        err = mmc_select_bus_width(card);
        if (!IS_ERR_VALUE(err)) {
+               val = EXT_CSD_TIMING_HS200 |
+                     card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
                err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                                  EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS200,
+                                  EXT_CSD_HS_TIMING, val,
                                   card->ext_csd.generic_cmd6_time,
                                   true, true, true);
                if (!err)

diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 4819cfb..15f2c4a 100644 (file)
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -391,6 +391,7 @@ struct _mmc_csd {
 #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_DRV_STR_SHIFT  4       /* Driver Strength shift */
 
 #define EXT_CSD_SEC_ER_EN      BIT(0)
 #define EXT_CSD_SEC_BD_BLK_EN  BIT(2)
@@ -442,4 +443,6 @@ struct _mmc_csd {
 #define MMC_SWITCH_MODE_CLEAR_BITS     0x02    /* Clear bits which are 1 in value */
 #define MMC_SWITCH_MODE_WRITE_BYTE     0x03    /* Set target to value */
 
+#define mmc_driver_type_mask(n)                (1 << (n))
+
 #endif /* LINUX_MMC_MMC_H */