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-rw-r--r--drivers/mmc/core/sd.c94
1 files changed, 22 insertions, 72 deletions
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 33c6f26c68d..8460568e521 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;
}