1 files changed, 22 insertions, 72 deletions

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 33c6f26c68d0..8460568e5213 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -290,8 +290,12 @@ static int mmc_read_switch(struct mmc_card *card)
                 return -ENOMEM;
         }
 
-        /* Find out the supported Bus Speed Modes. */
-        err = mmc_sd_switch(card, 0, 0, 1, status);
+        /*
+         * Find out the card's support bits with a mode 0 operation.
+         * The argument does not matter, as the support bits do not
+         * change with the arguments.
+         */
+        err = mmc_sd_switch(card, 0, 0, 0, status);
         if (err) {
                 /*
                  * If the host or the card can't do the switch,
@@ -312,46 +316,8 @@ static int mmc_read_switch(struct mmc_card *card)
 
         if (card->scr.sda_spec3) {
                 card->sw_caps.sd3_bus_mode = status[13];
-
-                /* Find out Driver Strengths supported by the card */
-                err = mmc_sd_switch(card, 0, 2, 1, status);
-                if (err) {
-                        /*
-                         * If the host or the card can't do the switch,
-                         * fail more gracefully.
-                         */
-                        if (err != -EINVAL && err != -ENOSYS && err != -EFAULT)
-                                goto out;
-
-                        pr_warning("%s: problem reading "
-                                "Driver Strength.\n",
-                                mmc_hostname(card->host));
-                        err = 0;
-
-                        goto out;
-                }
-
+                /* Driver Strengths supported by the card */
                 card->sw_caps.sd3_drv_type = status[9];
-
-                /* Find out Current Limits supported by the card */
-                err = mmc_sd_switch(card, 0, 3, 1, status);
-                if (err) {
-                        /*
-                         * If the host or the card can't do the switch,
-                         * fail more gracefully.
-                         */
-                        if (err != -EINVAL && err != -ENOSYS && err != -EFAULT)
-                                goto out;
-
-                        pr_warning("%s: problem reading "
-                                "Current Limit.\n",
-                                mmc_hostname(card->host));
-                        err = 0;
-
-                        goto out;
-                }
-
-                card->sw_caps.sd3_curr_limit = status[7];
         }
 
 out:
@@ -560,41 +526,24 @@ static int sd_set_current_limit(struct mmc_card *card, u8 *status)
          * Current limit switch is only defined for SDR50, SDR104, and DDR50
          * bus speed modes. For other bus speed modes, we do not change the
          * current limit.
+         * We only check host's capability here, if we set a limit that is
+         * higher than the card's maximum current, the card will be using its
+         * maximum current, e.g. if the card's maximum current is 300ma, and
+         * when we set current limit to 200ma, the card will draw 200ma, and
+         * when we set current limit to 400/600/800ma, the card will draw its
+         * maximum 300ma from the host.
          */
         if ((card->sd_bus_speed == UHS_SDR50_BUS_SPEED) ||
             (card->sd_bus_speed == UHS_SDR104_BUS_SPEED) ||
             (card->sd_bus_speed == UHS_DDR50_BUS_SPEED)) {
-                if (card->host->caps & MMC_CAP_MAX_CURRENT_800) {
-                        if (card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_800)
-                                current_limit = SD_SET_CURRENT_LIMIT_800;
-                        else if (card->sw_caps.sd3_curr_limit &
-                                        SD_MAX_CURRENT_600)
-                                current_limit = SD_SET_CURRENT_LIMIT_600;
-                        else if (card->sw_caps.sd3_curr_limit &
-                                        SD_MAX_CURRENT_400)
-                                current_limit = SD_SET_CURRENT_LIMIT_400;
-                        else if (card->sw_caps.sd3_curr_limit &
-                                        SD_MAX_CURRENT_200)
-                                current_limit = SD_SET_CURRENT_LIMIT_200;
-                } else if (card->host->caps & MMC_CAP_MAX_CURRENT_600) {
-                        if (card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_600)
-                                current_limit = SD_SET_CURRENT_LIMIT_600;
-                        else if (card->sw_caps.sd3_curr_limit &
-                                        SD_MAX_CURRENT_400)
-                                current_limit = SD_SET_CURRENT_LIMIT_400;
-                        else if (card->sw_caps.sd3_curr_limit &
-                                        SD_MAX_CURRENT_200)
-                                current_limit = SD_SET_CURRENT_LIMIT_200;
-                } else if (card->host->caps & MMC_CAP_MAX_CURRENT_400) {
-                        if (card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_400)
-                                current_limit = SD_SET_CURRENT_LIMIT_400;
-                        else if (card->sw_caps.sd3_curr_limit &
-                                        SD_MAX_CURRENT_200)
-                                current_limit = SD_SET_CURRENT_LIMIT_200;
-                } else if (card->host->caps & MMC_CAP_MAX_CURRENT_200) {
-                        if (card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_200)
-                                current_limit = SD_SET_CURRENT_LIMIT_200;
-                }
+                if (card->host->caps & MMC_CAP_MAX_CURRENT_800)
+                        current_limit = SD_SET_CURRENT_LIMIT_800;
+                else if (card->host->caps & MMC_CAP_MAX_CURRENT_600)
+                        current_limit = SD_SET_CURRENT_LIMIT_600;
+                else if (card->host->caps & MMC_CAP_MAX_CURRENT_400)
+                        current_limit = SD_SET_CURRENT_LIMIT_400;
+                else if (card->host->caps & MMC_CAP_MAX_CURRENT_200)
+                        current_limit = SD_SET_CURRENT_LIMIT_200;
         }
 
         if (current_limit != SD_SET_CURRENT_NO_CHANGE) {
@@ -607,6 +556,7 @@ static int sd_set_current_limit(struct mmc_card *card, u8 *status)
                                 mmc_hostname(card->host));
 
         }
+
         return 0;
 }