mmc: retry CMD1 in mmc_send_op_cond() until the eMMC is ready

According to eMMC specification v5.1 section 6.4.3, we should issue
CMD1 repeatedly in the idle state until the eMMC is ready even if
mmc_send_op_cond() send CMD1 with argument = 0. Otherwise some eMMC
devices seems to enter the inactive mode after mmc_complete_op_cond()
issued CMD0 when the eMMC device is busy.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 620bb93..725a367 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -669,12 +669,15 @@
 static int mmc_send_op_cond(struct mmc *mmc)
 {
 	int err, i;
+	int timeout = 1000;
+	uint start;
 
 	/* Some cards seem to need this */
 	mmc_go_idle(mmc);
 
+	start = get_timer(0);
  	/* Asking to the card its capabilities */
-	for (i = 0; i < 2; i++) {
+	for (i = 0; ; i++) {
 		err = mmc_send_op_cond_iter(mmc, i != 0);
 		if (err)
 			return err;
@@ -682,6 +685,10 @@
 		/* exit if not busy (flag seems to be inverted) */
 		if (mmc->ocr & OCR_BUSY)
 			break;
+
+		if (get_timer(start) > timeout)
+			return -ETIMEDOUT;
+		udelay(100);
 	}
 	mmc->op_cond_pending = 1;
 	return 0;