linux-kernel - [PATCH 4.8 18/92] mmc: sdhci: Fix CMD line reset interfering with ongoing data transfer

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Date:   Thu, 17 Nov 2016 11:31:51 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH 4.8 18/92] mmc: sdhci: Fix CMD line reset interfering with ongoing data transfer

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Adrian Hunter <adrian.hunter@...el.com>

commit 6ebebeab5185f50d55c6a24d0abe47e5dac1b191 upstream.

CMD line reset during an ongoing data transfer can cause the data transfer
to hang.  Fix by delaying the reset until the data transfer is finished.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/mmc/host/sdhci.c |   23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2269,10 +2269,8 @@ static bool sdhci_request_done(struct sd
 
 	for (i = 0; i < SDHCI_MAX_MRQS; i++) {
 		mrq = host->mrqs_done[i];
-		if (mrq) {
-			host->mrqs_done[i] = NULL;
+		if (mrq)
 			break;
-		}
 	}
 
 	if (!mrq) {
@@ -2303,6 +2301,17 @@ static bool sdhci_request_done(struct sd
 	 * upon error conditions.
 	 */
 	if (sdhci_needs_reset(host, mrq)) {
+		/*
+		 * Do not finish until command and data lines are available for
+		 * reset. Note there can only be one other mrq, so it cannot
+		 * also be in mrqs_done, otherwise host->cmd and host->data_cmd
+		 * would both be null.
+		 */
+		if (host->cmd || host->data_cmd) {
+			spin_unlock_irqrestore(&host->lock, flags);
+			return true;
+		}
+
 		/* Some controllers need this kick or reset won't work here */
 		if (host->quirks & SDHCI_QUIRK_CLOCK_BEFORE_RESET)
 			/* This is to force an update */
@@ -2310,10 +2319,8 @@ static bool sdhci_request_done(struct sd
 
 		/* Spec says we should do both at the same time, but Ricoh
 		   controllers do not like that. */
-		if (!host->cmd)
-			sdhci_do_reset(host, SDHCI_RESET_CMD);
-		if (!host->data_cmd)
-			sdhci_do_reset(host, SDHCI_RESET_DATA);
+		sdhci_do_reset(host, SDHCI_RESET_CMD);
+		sdhci_do_reset(host, SDHCI_RESET_DATA);
 
 		host->pending_reset = false;
 	}
@@ -2321,6 +2328,8 @@ static bool sdhci_request_done(struct sd
 	if (!sdhci_has_requests(host))
 		sdhci_led_deactivate(host);
 
+	host->mrqs_done[i] = NULL;
+
 	mmiowb();
 	spin_unlock_irqrestore(&host->lock, flags);