1 files changed, 17 insertions, 7 deletions

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index f417adc9feb1..6810b3a8e130 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -633,7 +633,11 @@ try_again:
          * to switch to 1.8V signaling level.  No 1.8v signalling if
          * UHS mode is not enabled to maintain compatibility and some
          * systems that claim 1.8v signalling in fact do not support
-         * it.
+         * it. Per SDIO spec v3, section 3.1.2, if the voltage is already
+         * 1.8v, the card sets S18A to 0 in the R4 response. So it will
+         * fails to check rocr & R4_18V_PRESENT,  but we still need to
+         * try to init uhs card. sdio_read_cccr will take over this task
+         * to make sure which speed mode should work.
          */
         if (!powered_resume && (rocr & ocr & R4_18V_PRESENT)) {
                 err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180,
@@ -645,9 +649,6 @@ try_again:
                 } else if (err) {
                         ocr &= ~R4_18V_PRESENT;
                 }
-                err = 0;
-        } else {
-                ocr &= ~R4_18V_PRESENT;
         }
 
         /*
@@ -704,11 +705,20 @@ try_again:
         }
 
         /*
-         * Read the common registers.
+         * Read the common registers. Note that we should try to
+         * validate whether UHS would work or not.
          */
         err = sdio_read_cccr(card, ocr);
-        if (err)
-                goto remove;
+        if (err) {
+                mmc_sdio_resend_if_cond(host, card);
+                if (ocr & R4_18V_PRESENT) {
+                        /* Retry init sequence, but without R4_18V_PRESENT. */
+                        retries = 0;
+                        goto try_again;
+                } else {
+                        goto remove;
+                }
+        }
 
         /*
          * Read the common CIS tuples.