Patch "mmc: sdhci: fix command response CRC error handling" has been added to the 4.5-stable tree

Patch "mmc: sdhci: fix command response CRC error handling" has been added to the 4.5-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mmc: sdhci: fix command response CRC error handling

to the 4.5-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mmc-sdhci-fix-command-response-crc-error-handling.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 71fcbda0fcddd0896c4982a484f6c8aa802d28b1 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Tue, 26 Jan 2016 13:39:45 +0000
Subject: mmc: sdhci: fix command response CRC error handling

From: Russell King <rmk+kernel@arm.linux.org.uk>

commit 71fcbda0fcddd0896c4982a484f6c8aa802d28b1 upstream.

When we get a response CRC error on a command, it means that the
response we received back from the card was not correct.  It does not
mean that the card did not receive the command correctly.  If the
command is one which initiates a data transfer, the card can enter the
data transfer state, and start sending data.

Moreover, if the request contained a data phase, we do not clean this
up, and this results in the driver triggering DMA API debug warnings,
and also creates a race condition in the driver, between running the
finish_tasklet and the data transfer interrupts, which can trigger a
"Got data interrupt" state dump.

Fix this by handing a response CRC error slightly differently: record
the failure of the data initiating command, but allow the remainder of
the request to be processed normally.  This is safe as core MMC checks
the status of all commands and data transfer phases of the request.

If the card does not initiate a data transfer, then we should time out
according to the data transfer parameters.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[ Fix missing parenthesis around bitwise-AND expression, and tweak subject ]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mmc/host/sdhci.c |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2330,6 +2330,23 @@ static void sdhci_cmd_irq(struct sdhci_h
 		else
 			host->cmd->error = -EILSEQ;
 
+		/*
+		 * If this command initiates a data phase and a response
+		 * CRC error is signalled, the card can start transferring
+		 * data - the card may have received the command without
+		 * error.  We must not terminate the mmc_request early.
+		 *
+		 * If the card did not receive the command or returned an
+		 * error which prevented it sending data, the data phase
+		 * will time out.
+		 */
+		if (host->cmd->data &&
+		    (intmask & (SDHCI_INT_CRC | SDHCI_INT_TIMEOUT)) ==
+		     SDHCI_INT_CRC) {
+			host->cmd = NULL;
+			return;
+		}
+
 		tasklet_schedule(&host->finish_tasklet);
 		return;
 	}


Patches currently in stable-queue which might be from rmk+kernel@arm.linux.org.uk are

queue-4.5/mmc-sdhci-fix-command-response-crc-error-handling.patch
queue-4.5/mmc-sdhci-avoid-unnecessary-mapping-unmapping-of-align-buffer.patch
queue-4.5/mmc-sdhci-move-initialisation-of-command-error-member.patch
queue-4.5/mmc-sdhci-fix-data-timeout-part-2.patch
queue-4.5/mmc-sdhci-clean-up-command-error-handling.patch
queue-4.5/mmc-sdhci-further-fix-for-dma-unmapping-in-sdhci_post_req.patch
queue-4.5/mmc-sdhci-pxav3-fix-higher-speed-mode-capabilities.patch
queue-4.5/mmc-sdhci-fix-data-timeout-part-1.patch
queue-4.5/mmc-sdhci-plug-dma-mapping-leak-on-error.patch