dm: implement a DMA uclass

Implement a DMA uclass so that the devices like ethernet, spi,
mmc etc can offload the data transfers from/to the device and
memory.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>

2 files changed, 87 insertions, 0 deletions

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 73cd3ac94c1..3bea30807db 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -31,6 +31,7 @@ enum uclass_id {
 	UCLASS_CROS_EC,		/* Chrome OS EC */
 	UCLASS_DISK,		/* Disk controller, e.g. SATA */
 	UCLASS_DISPLAY,		/* Display (e.g. DisplayPort, HDMI) */
+	UCLASS_DMA,		/* Direct Memory Access */
 	UCLASS_RAM,		/* RAM controller */
 	UCLASS_ETH,		/* Ethernet device */
 	UCLASS_GPIO,		/* Bank of general-purpose I/O pins */
diff --git a/include/dma.h b/include/dma.h
new file mode 100644
index 00000000000..71fa77f2ea8
--- /dev/null
+++ b/include/dma.h
@@ -0,0 +1,86 @@
+/*
+ * (C) Copyright 2015
+ *     Texas Instruments Incorporated, <www.ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#ifndef _DMA_H_
+#define _DMA_H_
+
+/*
+ * enum dma_direction - dma transfer direction indicator
+ * @DMA_MEM_TO_MEM: Memcpy mode
+ * @DMA_MEM_TO_DEV: From Memory to Device
+ * @DMA_DEV_TO_MEM: From Device to Memory
+ * @DMA_DEV_TO_DEV: From Device to Device
+ */
+enum dma_direction {
+	DMA_MEM_TO_MEM,
+	DMA_MEM_TO_DEV,
+	DMA_DEV_TO_MEM,
+	DMA_DEV_TO_DEV,
+};
+
+#define DMA_SUPPORTS_MEM_TO_MEM	BIT(0)
+#define DMA_SUPPORTS_MEM_TO_DEV	BIT(1)
+#define DMA_SUPPORTS_DEV_TO_MEM	BIT(2)
+#define DMA_SUPPORTS_DEV_TO_DEV	BIT(3)
+
+/*
+ * struct dma_ops - Driver model DMA operations
+ *
+ * The uclass interface is implemented by all DMA devices which use
+ * driver model.
+ */
+struct dma_ops {
+	/*
+	 * Get the current timer count
+	 *
+	 * @dev: The DMA device
+	 * @direction: direction of data transfer should be one from
+		       enum dma_direction
+	 * @dst: Destination pointer
+	 * @src: Source pointer
+	 * @len: Length of the data to be copied.
+	 * @return: 0 if OK, -ve on error
+	 */
+	int (*transfer)(struct udevice *dev, int direction, void *dst,
+			void *src, size_t len);
+};
+
+/*
+ * struct dma_dev_priv - information about a device used by the uclass
+ *
+ * @supported: mode of transfers that DMA can support, should be
+ *	       one/multiple of DMA_SUPPORTS_*
+ */
+struct dma_dev_priv {
+	u32 supported;
+};
+
+/*
+ * dma_get_device - get a DMA device which supports transfer
+ * type of transfer_type
+ *
+ * @transfer_type - transfer type should be one/multiple of
+ *		    DMA_SUPPORTS_*
+ * @devp - udevice pointer to return the found device
+ * @return - will return on success and devp will hold the
+ *	     pointer to the device
+ */
+int dma_get_device(u32 transfer_type, struct udevice **devp);
+
+/*
+ * dma_memcpy - try to use DMA to do a mem copy which will be
+ *		much faster than CPU mem copy
+ *
+ * @dst - destination pointer
+ * @src - souce pointer
+ * @len - data length to be copied
+ * @return - on successful transfer returns no of bytes
+	     transferred and on failure return error code.
+ */
+int dma_memcpy(void *dst, void *src, size_t len);
+
+#endif	/* _DMA_H_ */