mmc: sd: Fix sd current limit setting

Host has different current capabilities at different voltages, we need
to record these settings seperately. The defined voltages are 1.8/3.0/3.3.
For other voltages, we do not touch current limit setting.

Before we set the current limit for the sd card, find out the host's
operating voltage first and then find out the current capabilities of
the host at that voltage to set the current limit.

Signed-off-by: Aaron Lu <aaron.lu@amd.com>
Reviewed-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 54 insertions, 15 deletions

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 8460568e521..441bdf472c9 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -517,15 +517,54 @@ static int sd_set_bus_speed_mode(struct mmc_card *card, u8 *status)
         return 0;
 }
 
+/* Get host's max current setting at its current voltage */
+static u32 sd_get_host_max_current(struct mmc_host *host)
+{
+        u32 voltage, max_current;
+
+        voltage = 1 << host->ios.vdd;
+        switch (voltage) {
+        case MMC_VDD_165_195:
+                max_current = host->max_current_180;
+                break;
+        case MMC_VDD_29_30:
+        case MMC_VDD_30_31:
+                max_current = host->max_current_300;
+                break;
+        case MMC_VDD_32_33:
+        case MMC_VDD_33_34:
+                max_current = host->max_current_330;
+                break;
+        default:
+                max_current = 0;
+        }
+
+        return max_current;
+}
+
 static int sd_set_current_limit(struct mmc_card *card, u8 *status)
 {
         int current_limit = SD_SET_CURRENT_NO_CHANGE;
         int err;
+        u32 max_current;
 
         /*
          * 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.
+         */
+        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))
+                return 0;
+
+        /*
+         * Host has different current capabilities when operating at
+         * different voltages, so find out its max current first.
+         */
+        max_current = sd_get_host_max_current(card->host);
+
+        /*
          * 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
@@ -533,18 +572,14 @@ static int sd_set_current_limit(struct mmc_card *card, u8 *status)
          * 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)
-                        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 (max_current >= 800)
+                current_limit = SD_SET_CURRENT_LIMIT_800;
+        else if (max_current >= 600)
+                current_limit = SD_SET_CURRENT_LIMIT_600;
+        else if (max_current >= 400)
+                current_limit = SD_SET_CURRENT_LIMIT_400;
+        else if (max_current >= 200)
+                current_limit = SD_SET_CURRENT_LIMIT_200;
 
         if (current_limit != SD_SET_CURRENT_NO_CHANGE) {
                 err = mmc_sd_switch(card, 1, 3, current_limit, status);
@@ -677,6 +712,7 @@ struct device_type sd_type = {
 int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
 {
         int err;
+        u32 max_current;
 
         /*
          * Since we're changing the OCR value, we seem to
@@ -704,9 +740,12 @@ int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
             MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR104 | MMC_CAP_UHS_DDR50))
                 ocr |= SD_OCR_S18R;
 
-        /* If the host can supply more than 150mA, XPC should be set to 1. */
-        if (host->caps & (MMC_CAP_SET_XPC_330 | MMC_CAP_SET_XPC_300 |
-            MMC_CAP_SET_XPC_180))
+        /*
+         * If the host can supply more than 150mA at current voltage,
+         * XPC should be set to 1.
+         */
+        max_current = sd_get_host_max_current(host);
+        if (max_current > 150)
                 ocr |= SD_OCR_XPC;
 
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