ARM: 7726/1: mmc: mmci: Add card_busy function to improve UHS card support

To verify a signal voltage switch at initialization of UHS cards the
.card_busy callback is used. For some of the ST-variants, card busy
detection on the DAT0 pin is supported.

We extend the variant struct with a busy_detect flag to indicate
support for it. A corresponding busy detect function, which polls the
busy status bit, is then set to the .card_busy callback.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mmc/host/mmci.h

@@ -94,6 +94,7 @@
 /* Extended status bits for the ST Micro variants */
 #define MCI_ST_SDIOIT		(1 << 22)
 #define MCI_ST_CEATAEND		(1 << 23)
+#define MCI_ST_CARDBUSY		(1 << 24)
 
 #define MMCICLEAR		0x038
 #define MCI_CMDCRCFAILCLR	(1 << 0)
@@ -110,6 +111,7 @@
 /* Extended status bits for the ST Micro variants */
 #define MCI_ST_SDIOITC		(1 << 22)
 #define MCI_ST_CEATAENDC	(1 << 23)
+#define MCI_ST_BUSYENDC		(1 << 24)
 
 #define MMCIMASK0		0x03c
 #define MCI_CMDCRCFAILMASK	(1 << 0)