include/dma.h

   1 /*
   2  * (C) Copyright 2015
   3  *     Texas Instruments Incorporated, <www.ti.com>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #ifndef _DMA_H_
   9 #define _DMA_H_
  10
  11 /*
  12  * enum dma_direction - dma transfer direction indicator
  13  * @DMA_MEM_TO_MEM: Memcpy mode
  14  * @DMA_MEM_TO_DEV: From Memory to Device
  15  * @DMA_DEV_TO_MEM: From Device to Memory
  16  * @DMA_DEV_TO_DEV: From Device to Device
  17  */
  18 enum dma_direction {
  19         DMA_MEM_TO_MEM,
  20         DMA_MEM_TO_DEV,
  21         DMA_DEV_TO_MEM,
  22         DMA_DEV_TO_DEV,
  23 };
  24
  25 #define DMA_SUPPORTS_MEM_TO_MEM BIT(0)
  26 #define DMA_SUPPORTS_MEM_TO_DEV BIT(1)
  27 #define DMA_SUPPORTS_DEV_TO_MEM BIT(2)
  28 #define DMA_SUPPORTS_DEV_TO_DEV BIT(3)
  29
  30 /*
  31  * struct dma_ops - Driver model DMA operations
  32  *
  33  * The uclass interface is implemented by all DMA devices which use
  34  * driver model.
  35  */
  36 struct dma_ops {
  37         /*
  38          * Get the current timer count
  39          *
  40          * @dev: The DMA device
  41          * @direction: direction of data transfer should be one from
  42                        enum dma_direction
  43          * @dst: Destination pointer
  44          * @src: Source pointer
  45          * @len: Length of the data to be copied.
  46          * @return: 0 if OK, -ve on error
  47          */
  48         int (*transfer)(struct udevice *dev, int direction, void *dst,
  49                         void *src, size_t len);
  50 };
  51
  52 /*
  53  * struct dma_dev_priv - information about a device used by the uclass
  54  *
  55  * @supported: mode of transfers that DMA can support, should be
  56  *             one/multiple of DMA_SUPPORTS_*
  57  */
  58 struct dma_dev_priv {
  59         u32 supported;
  60 };
  61
  62 /*
  63  * dma_get_device - get a DMA device which supports transfer
  64  * type of transfer_type
  65  *
  66  * @transfer_type - transfer type should be one/multiple of
  67  *                  DMA_SUPPORTS_*
  68  * @devp - udevice pointer to return the found device
  69  * @return - will return on success and devp will hold the
  70  *           pointer to the device
  71  */
  72 int dma_get_device(u32 transfer_type, struct udevice **devp);
  73
  74 /*
  75  * dma_memcpy - try to use DMA to do a mem copy which will be
  76  *              much faster than CPU mem copy
  77  *
  78  * @dst - destination pointer
  79  * @src - souce pointer
  80  * @len - data length to be copied
  81  * @return - on successful transfer returns no of bytes
  82              transferred and on failure return error code.
  83  */
  84 int dma_memcpy(void *dst, void *src, size_t len);
  85
  86 #endif  /* _DMA_H_ */