mmc: sdio: add a quirk for broken SDIO_CCCR_INTx polling

Polling SDIO_CCCR_INTx could create a fake interrupt with Marvell
SD8797 card. Add a quirk to handle this case. The fixup here is
to issue a dummy CMD52 read to function 0 register 0xff, and this
dummy read must be right after SDIO_CCCR_INTx is read.

Patch has been verified on a dw_mmc controller (Samsung Chromebook)
with MMC_CAP_SDIO_IRQ disabled.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>
diff --git a/drivers/mmc/core/quirks.c b/drivers/mmc/core/quirks.c
index 06ee1ae..6c36fcc 100644
--- a/drivers/mmc/core/quirks.c
+++ b/drivers/mmc/core/quirks.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/mmc/card.h>
+#include <linux/mmc/sdio_ids.h>
 
 #ifndef SDIO_VENDOR_ID_TI
 #define SDIO_VENDOR_ID_TI		0x0097
@@ -30,6 +31,10 @@
 #define SDIO_DEVICE_ID_STE_CW1200	0x2280
 #endif
 
+#ifndef SDIO_DEVICE_ID_MARVELL_8797_F0
+#define SDIO_DEVICE_ID_MARVELL_8797_F0	0x9128
+#endif
+
 /*
  * This hook just adds a quirk for all sdio devices
  */
@@ -58,6 +63,9 @@
 	SDIO_FIXUP(SDIO_VENDOR_ID_STE, SDIO_DEVICE_ID_STE_CW1200,
 		   add_quirk, MMC_QUIRK_BROKEN_BYTE_MODE_512),
 
+	SDIO_FIXUP(SDIO_VENDOR_ID_MARVELL, SDIO_DEVICE_ID_MARVELL_8797_F0,
+		   add_quirk, MMC_QUIRK_BROKEN_IRQ_POLLING),
+
 	END_FIXUP
 };