mmc: sdhci: Add ADMA2 64-bit addressing support for V4 mode

ADMA2 64-bit addressing support is divided into V3 mode and V4 mode.
So there are two kinds of descriptors for ADMA2 64-bit addressing
i.e. 96-bit Descriptor for V3 mode, and 128-bit Descriptor for V4
mode. 128-bit Descriptor is aligned to 8-byte.

For V4 mode, ADMA2 64-bit addressing is enabled via Host Control 2
register.

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
[Ulf: Fixed conflict while applying]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci.c

@@ -266,6 +266,52 @@ static void sdhci_set_default_irqs(struct sdhci_host *host)
 	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
 }
 
+static void sdhci_config_dma(struct sdhci_host *host)
+{
+	u8 ctrl;
+	u16 ctrl2;
+
+	if (host->version < SDHCI_SPEC_200)
+		return;
+
+	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
+
+	/*
+	 * Always adjust the DMA selection as some controllers
+	 * (e.g. JMicron) can't do PIO properly when the selection
+	 * is ADMA.
+	 */
+	ctrl &= ~SDHCI_CTRL_DMA_MASK;
+	if (!(host->flags & SDHCI_REQ_USE_DMA))
+		goto out;
+
+	/* Note if DMA Select is zero then SDMA is selected */
+	if (host->flags & SDHCI_USE_ADMA)
+		ctrl |= SDHCI_CTRL_ADMA32;
+
+	if (host->flags & SDHCI_USE_64_BIT_DMA) {
+		/*
+		 * If v4 mode, all supported DMA can be 64-bit addressing if
+		 * controller supports 64-bit system address, otherwise only
+		 * ADMA can support 64-bit addressing.
+		 */
+		if (host->v4_mode) {
+			ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+			ctrl2 |= SDHCI_CTRL_64BIT_ADDR;
+			sdhci_writew(host, ctrl2, SDHCI_HOST_CONTROL2);
+		} else if (host->flags & SDHCI_USE_ADMA) {
+			/*
+			 * Don't need to undo SDHCI_CTRL_ADMA32 in order to
+			 * set SDHCI_CTRL_ADMA64.
+			 */
+			ctrl |= SDHCI_CTRL_ADMA64;
+		}
+	}
+
+out:
+	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+}
+
 static void sdhci_init(struct sdhci_host *host, int soft)
 {
 	struct mmc_host *mmc = host->mmc;
@@ -922,7 +968,6 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
 
 static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
 {
-	u8 ctrl;
 	struct mmc_data *data = cmd->data;
 
 	host->data_timeout = 0;
@@ -1018,25 +1063,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
 		}
 	}
 
-	/*
-	 * Always adjust the DMA selection as some controllers
-	 * (e.g. JMicron) can't do PIO properly when the selection
-	 * is ADMA.
-	 */
-	if (host->version >= SDHCI_SPEC_200) {
-		ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
-		ctrl &= ~SDHCI_CTRL_DMA_MASK;
-		if ((host->flags & SDHCI_REQ_USE_DMA) &&
-			(host->flags & SDHCI_USE_ADMA)) {
-			if (host->flags & SDHCI_USE_64_BIT_DMA)
-				ctrl |= SDHCI_CTRL_ADMA64;
-			else
-				ctrl |= SDHCI_CTRL_ADMA32;
-		} else {
-			ctrl |= SDHCI_CTRL_SDMA;
-		}
-		sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
-	}
+	sdhci_config_dma(host);
 
 	if (!(host->flags & SDHCI_REQ_USE_DMA)) {
 		int flags;
@@ -3527,6 +3554,19 @@ static int sdhci_allocate_bounce_buffer(struct sdhci_host *host)
 	return 0;
 }
 
+static inline bool sdhci_can_64bit_dma(struct sdhci_host *host)
+{
+	/*
+	 * According to SD Host Controller spec v4.10, bit[27] added from
+	 * version 4.10 in Capabilities Register is used as 64-bit System
+	 * Address support for V4 mode.
+	 */
+	if (host->version >= SDHCI_SPEC_410 && host->v4_mode)
+		return host->caps & SDHCI_CAN_64BIT_V4;
+
+	return host->caps & SDHCI_CAN_64BIT;
+}
+
 int sdhci_setup_host(struct sdhci_host *host)
 {
 	struct mmc_host *mmc;
@@ -3598,7 +3638,7 @@ int sdhci_setup_host(struct sdhci_host *host)
 	 * SDHCI_QUIRK2_BROKEN_64_BIT_DMA must be left to the drivers to
 	 * implement.
 	 */
-	if (host->caps & SDHCI_CAN_64BIT)
+	if (sdhci_can_64bit_dma(host))
 		host->flags |= SDHCI_USE_64_BIT_DMA;
 
 	if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) {
@@ -3626,8 +3666,8 @@ int sdhci_setup_host(struct sdhci_host *host)
 
 		if (host->flags & SDHCI_USE_64_BIT_DMA) {
 			host->adma_table_sz = host->adma_table_cnt *
-					      SDHCI_ADMA2_64_DESC_SZ;
-			host->desc_sz = SDHCI_ADMA2_64_DESC_SZ;
+					      SDHCI_ADMA2_64_DESC_SZ(host);
+			host->desc_sz = SDHCI_ADMA2_64_DESC_SZ(host);
 		} else {
 			host->adma_table_sz = host->adma_table_cnt *
 					      SDHCI_ADMA2_32_DESC_SZ;
@@ -3635,7 +3675,11 @@ int sdhci_setup_host(struct sdhci_host *host)
 		}
 
 		host->align_buffer_sz = SDHCI_MAX_SEGS * SDHCI_ADMA2_ALIGN;
-		buf = dma_alloc_coherent(mmc_dev(mmc), host->align_buffer_sz +
+		/*
+		 * Use zalloc to zero the reserved high 32-bits of 128-bit
+		 * descriptors so that they never need to be written.
+		 */
+		buf = dma_zalloc_coherent(mmc_dev(mmc), host->align_buffer_sz +
 					 host->adma_table_sz, &dma, GFP_KERNEL);
 		if (!buf) {
 			pr_warn("%s: Unable to allocate ADMA buffers - falling back to standard DMA\n",

drivers/mmc/host/sdhci.h

@@ -185,6 +185,7 @@
 #define  SDHCI_CTRL_EXEC_TUNING		0x0040
 #define  SDHCI_CTRL_TUNED_CLK		0x0080
 #define  SDHCI_CTRL_V4_MODE		0x1000
+#define  SDHCI_CTRL_64BIT_ADDR		0x2000
 #define  SDHCI_CTRL_PRESET_VAL_ENABLE	0x8000
 
 #define SDHCI_CAPABILITIES	0x40
@@ -205,6 +206,7 @@
 #define  SDHCI_CAN_VDD_330	0x01000000
 #define  SDHCI_CAN_VDD_300	0x02000000
 #define  SDHCI_CAN_VDD_180	0x04000000
+#define  SDHCI_CAN_64BIT_V4	0x08000000
 #define  SDHCI_CAN_64BIT	0x10000000
 
 #define  SDHCI_SUPPORT_SDR50	0x00000001
@@ -309,8 +311,14 @@ struct sdhci_adma2_32_desc {
  */
 #define SDHCI_ADMA2_DESC_ALIGN	8
 
-/* ADMA2 64-bit DMA descriptor size */
-#define SDHCI_ADMA2_64_DESC_SZ	12
+/*
+ * ADMA2 64-bit DMA descriptor size
+ * According to SD Host Controller spec v4.10, there are two kinds of
+ * descriptors for 64-bit addressing mode: 96-bit Descriptor and 128-bit
+ * Descriptor, if Host Version 4 Enable is set in the Host Control 2
+ * register, 128-bit Descriptor will be selected.
+ */
+#define SDHCI_ADMA2_64_DESC_SZ(host)	((host)->v4_mode ? 16 : 12)
 
 /*
  * ADMA2 64-bit descriptor. Note 12-byte descriptor can't always be 8-byte