include/dma.h

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