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

[haibo.chen at nxp.com]

From: Haibo Chen <haibo.chen at nxp.com>

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. This patch also align with
Linux 5.7.

Signed-off-by: Haibo Chen <haibo.chen at nxp.com>
---
 drivers/mmc/mmc.c | 41 +++++++++++++++++++++++++++++++++--------
 1 file changed, 33 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 523c055967..509549756b 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -664,21 +664,46 @@ static int mmc_send_op_cond_iter(struct mmc *mmc, int use_arg)
 
 static int mmc_send_op_cond(struct mmc *mmc)
 {
+	struct mmc_cmd cmd;
 	int err, i;
+	int timeout = 1000;
+	ulong start;
 
 	/* Some cards seem to need this */
 	mmc_go_idle(mmc);
 
- 	/* Asking to the card its capabilities */
-	for (i = 0; i < 2; i++) {
-		err = mmc_send_op_cond_iter(mmc, i != 0);
+	cmd.cmdidx = MMC_CMD_SEND_OP_COND;
+	cmd.resp_type = MMC_RSP_R3;
+	cmd.cmdarg = 0;
+
+	start = get_timer(0);
+	/*
+	 * According to eMMC specification v5.1 section 6.4.3, we
+	 * should issue CMD1 repeatedly in the idle state until
+	 * the eMMC is ready. Otherwise some eMMC devices seem to enter
+	 * the inactive mode after mmc_complete_op_cond() issued CMD0 when
+	 * the eMMC device is busy.
+	 */
+	while (1) {
+		err = mmc_send_cmd(mmc, &cmd, NULL);
 		if (err)
 			return err;
-
-		/* exit if not busy (flag seems to be inverted) */
-		if (mmc->ocr & OCR_BUSY)
-			break;
+		if (mmc_host_is_spi(mmc)) {
+			if (!(cmd.response[0] & (1 << 0)))
+				break;
+		} else {
+			mmc->ocr = cmd.response[0];
+			/* exit if not busy (flag seems to be inverted) */
+			if (mmc->ocr & OCR_BUSY)
+				break;
+		}
+		if (get_timer(start) > timeout)
+			return -EOPNOTSUPP;
+		udelay(100);
+		if (!mmc_host_is_spi(mmc))
+			cmd.cmdarg = cmd.response[0] | (1 << 30);
 	}
+
 	mmc->op_cond_pending = 1;
 	return 0;
 }
@@ -691,7 +716,7 @@ static int mmc_complete_op_cond(struct mmc *mmc)
 	int err;
 
 	mmc->op_cond_pending = 0;
-	if (!(mmc->ocr & OCR_BUSY)) {
+	if (mmc->ocr & OCR_BUSY) {
 		/* Some cards seem to need this */
 		mmc_go_idle(mmc);
 
-- 
2.17.1