mmc: sdhci: Add ADMA3 DMA support for V4 enabled host

Below are the supported DMA types in Host Control1 Register
with Version 4 enable
b'00 - SDMA
b'01 - Not Used
b'10 - ADMA2
b'11 - ADMA2 or ADMA3

ADMA3 uses Command Descriptor to issue an SD command.
A multi-block data transfer is performed by using a pair of CMD
descriptor and ADMA2 descriptor.

ADMA3 performs multiple of multi-block data transfer by using
Integrated Descriptor which is more suitable for Command Queuing
to fetch both Command and Transfer descriptors.

Host Capabilities register indicates the supports of ADMA3 DMA.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci.c

@@ -3359,7 +3359,14 @@ void sdhci_cqe_enable(struct mmc_host *mmc)
 
 	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
 	ctrl &= ~SDHCI_CTRL_DMA_MASK;
-	if (host->flags & SDHCI_USE_64_BIT_DMA)
+	/*
+	 * Host from V4.10 supports ADMA3 DMA type.
+	 * ADMA3 performs integrated descriptor which is more suitable
+	 * for cmd queuing to fetch both command and transfer descriptors.
+	 */
+	if (host->v4_mode && (host->caps1 & SDHCI_CAN_DO_ADMA3))
+		ctrl |= SDHCI_CTRL_ADMA3;
+	else if (host->flags & SDHCI_USE_64_BIT_DMA)
 		ctrl |= SDHCI_CTRL_ADMA64;
 	else
 		ctrl |= SDHCI_CTRL_ADMA32;

drivers/mmc/host/sdhci.h

@@ -92,6 +92,7 @@
 #define   SDHCI_CTRL_ADMA1	0x08
 #define   SDHCI_CTRL_ADMA32	0x10
 #define   SDHCI_CTRL_ADMA64	0x18
+#define   SDHCI_CTRL_ADMA3	0x18
 #define   SDHCI_CTRL_8BITBUS	0x20
 #define  SDHCI_CTRL_CDTEST_INS	0x40
 #define  SDHCI_CTRL_CDTEST_EN	0x80
@@ -234,6 +235,7 @@
 #define  SDHCI_RETUNING_MODE_SHIFT		14
 #define  SDHCI_CLOCK_MUL_MASK	0x00FF0000
 #define  SDHCI_CLOCK_MUL_SHIFT	16
+#define  SDHCI_CAN_DO_ADMA3	0x08000000
 #define  SDHCI_SUPPORT_HS400	0x80000000 /* Non-standard */
 
 #define SDHCI_CAPABILITIES_1	0x44