mmc: fsl_esdhc: increase data transaction timeout to 500ms

[oweals/u-boot.git] / drivers / mmc / fsl_esdhc.c

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index 1ccc576c347c6f0f669ab35e247641df252ba1eb..6827ffb431da36a9681160878055c8511b4c9c5b 100644 (file)
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -252,8 +252,15 @@ static int esdhc_setup_data(struct mmc *mmc, struct mmc_data *data)
         * Rounding up to next power of 2
         * => timeout + 13 = log2(mmc->clock/4) + 1
         * => timeout + 13 = fls(mmc->clock/4)
+        *
+        * However, the MMC spec "It is strongly recommended for hosts to
+        * implement more than 500ms timeout value even if the card
+        * indicates the 250ms maximum busy length."  Even the previous
+        * value of 300ms is known to be insufficient for some cards.
+        * So, we use
+        * => timeout + 13 = fls(mmc->clock/2)
         */
-       timeout = fls(mmc->clock/4);
+       timeout = fls(mmc->clock/2);
        timeout -= 13;
 
        if (timeout > 14)