mmc: Wait for card_busy before starting sdio requests

Some sdio wifi chips will not work properly if we try to start new
sdio-rw requests while the device is signalling that it is busy.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 2092a89dcf76b32fb15676d328e841d4eecaa94d..21cda23b247c3044b1ec65f039af1ac1161391b4 100644 (file)
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -206,6 +206,23 @@ static void __mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
                return;
        }
 
+       /*
+        * For sdio rw commands we must wait for card busy otherwise some
+        * sdio devices won't work properly.
+        */
+       if (mmc_is_io_op(mrq->cmd->opcode) && host->ops->card_busy) {
+               int tries = 500; /* Wait aprox 500ms at maximum */
+
+               while (host->ops->card_busy(host) && --tries)
+                       mmc_delay(1);
+
+               if (tries == 0) {
+                       mrq->cmd->error = -EBUSY;
+                       mmc_request_done(host, mrq);
+                       return;
+               }
+       }
+
        host->ops->request(host, mrq);
 }