[PATCH 2/3] mmc: sdhci_am654: Clear ITAPDLY on tuning failure

[Diogo Ivo (Schneider Electric)]

When tuning fails, stale ITAPDLY values can persist and interfere with
subsequent I/O accesses, for example in DDR50 mode in cards with no tuning
support. Move the ITAPDLY enable setting out of the tuning loop to after
successful tuning, and explicitly clear ITAPDLY (delay and enable) when
tuning fails so that we are sure only working values are actually left in
hardware.

Fixes: 901d16e46296 ("mmc: sdhci_am654: Add retry tuning")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Diogo Ivo (Schneider Electric) <diogo.ivo@xxxxxxxxxxx>
---
 drivers/mmc/host/sdhci_am654.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
index f76aab7e3a16..806544db0128 100644
--- a/drivers/mmc/host/sdhci_am654.c
+++ b/drivers/mmc/host/sdhci_am654.c
@@ -537,11 +537,8 @@ static int sdhci_am654_do_tuning(struct sdhci_host *host,
 
 	memset(fail_window, 0, sizeof(fail_window));
 
-	/* Enable ITAPDLY */
-	sdhci_am654->itap_del_ena[timing] = 0x1;
-
 	for (itap = 0; itap < ITAPDLY_LENGTH; itap++) {
-		sdhci_am654_write_itapdly(sdhci_am654, itap, sdhci_am654->itap_del_ena[timing]);
+		sdhci_am654_write_itapdly(sdhci_am654, itap, 0x1);
 
 		curr_pass = !mmc_send_tuning(host->mmc, opcode, NULL);
 
@@ -584,10 +581,15 @@ static int sdhci_am654_platform_execute_tuning(struct sdhci_host *host,
 
 	if (itapdly < 0) {
 		dev_err(dev, "Failed to find itapdly, fail tuning\n");
+		/* Explicitly clear ITAPDLY */
+		sdhci_am654_write_itapdly(sdhci_am654, 0, 0);
 		return -1;
 	}
 
 	dev_dbg(dev, "Passed tuning, final itapdly=%d\n", itapdly);
+
+	/* Enable ITAPDLY */
+	sdhci_am654->itap_del_ena[timing] = 0x1;
 	sdhci_am654_write_itapdly(sdhci_am654, itapdly, sdhci_am654->itap_del_ena[timing]);
 	/* Save ITAPDLY */
 	sdhci_am654->itap_del_sel[timing] = itapdly;

-- 
2.55.0