[PATCH 2/2] mmc: sdhci: Add a quirk for broken command queuing

[Adrian Hunter <adrian.hunter@intel.com>]

Command queuing has been reported broken on some systems based on Intel
GLK. A separate patch disables command queuing in some cases.

This patch adds a quirk for broken command queuing, which enables users
with problems to disable command queuing using sdhci module parameters for
quirks.

Fixes: 8ee82bda230f ("mmc: sdhci-pci: Add CQHCI support for Intel GLK")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
---
 drivers/mmc/host/sdhci.c | 3 +++
 drivers/mmc/host/sdhci.h | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 3140fe2e5dba..f4540f9892ce 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3769,6 +3769,9 @@ int sdhci_setup_host(struct sdhci_host *host)
 		       mmc_hostname(mmc), host->version);
 	}
 
+	if (host->quirks & SDHCI_QUIRK_BROKEN_CQE)
+		mmc->caps2 &= ~MMC_CAP2_CQE;
+
 	if (host->quirks & SDHCI_QUIRK_FORCE_DMA)
 		host->flags |= SDHCI_USE_SDMA;
 	else if (!(host->caps & SDHCI_CAN_DO_SDMA))
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 0ed3e0eaef5f..fe83ece6965b 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -409,6 +409,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK_BROKEN_CARD_DETECTION		(1<<15)
 /* Controller reports inverted write-protect state */
 #define SDHCI_QUIRK_INVERTED_WRITE_PROTECT		(1<<16)
+/* Controller has unusable command queue engine */
+#define SDHCI_QUIRK_BROKEN_CQE				(1<<17)
 /* Controller does not like fast PIO transfers */
 #define SDHCI_QUIRK_PIO_NEEDS_DELAY			(1<<18)
 /* Controller does not have a LED */
-- 
2.17.1