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	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>
		
			
				
	
	
		
			87 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			87 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * (C) Copyright 2015
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 *     Texas Instruments Incorporated, <www.ti.com>
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 *
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 * SPDX-License-Identifier:     GPL-2.0+
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 */
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#ifndef _DMA_H_
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#define _DMA_H_
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/*
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 * enum dma_direction - dma transfer direction indicator
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 * @DMA_MEM_TO_MEM: Memcpy mode
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 * @DMA_MEM_TO_DEV: From Memory to Device
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 * @DMA_DEV_TO_MEM: From Device to Memory
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 * @DMA_DEV_TO_DEV: From Device to Device
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 */
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enum dma_direction {
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	DMA_MEM_TO_MEM,
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	DMA_MEM_TO_DEV,
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	DMA_DEV_TO_MEM,
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	DMA_DEV_TO_DEV,
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};
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#define DMA_SUPPORTS_MEM_TO_MEM	BIT(0)
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#define DMA_SUPPORTS_MEM_TO_DEV	BIT(1)
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#define DMA_SUPPORTS_DEV_TO_MEM	BIT(2)
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#define DMA_SUPPORTS_DEV_TO_DEV	BIT(3)
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/*
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 * struct dma_ops - Driver model DMA operations
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 *
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 * The uclass interface is implemented by all DMA devices which use
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 * driver model.
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 */
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struct dma_ops {
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	/*
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	 * Get the current timer count
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	 *
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	 * @dev: The DMA device
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	 * @direction: direction of data transfer should be one from
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		       enum dma_direction
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	 * @dst: Destination pointer
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	 * @src: Source pointer
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	 * @len: Length of the data to be copied.
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	 * @return: 0 if OK, -ve on error
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	 */
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	int (*transfer)(struct udevice *dev, int direction, void *dst,
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			void *src, size_t len);
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};
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/*
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 * struct dma_dev_priv - information about a device used by the uclass
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 *
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 * @supported: mode of transfers that DMA can support, should be
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 *	       one/multiple of DMA_SUPPORTS_*
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 */
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struct dma_dev_priv {
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	u32 supported;
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};
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/*
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 * dma_get_device - get a DMA device which supports transfer
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 * type of transfer_type
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 *
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 * @transfer_type - transfer type should be one/multiple of
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 *		    DMA_SUPPORTS_*
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 * @devp - udevice pointer to return the found device
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 * @return - will return on success and devp will hold the
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 *	     pointer to the device
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 */
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int dma_get_device(u32 transfer_type, struct udevice **devp);
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/*
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 * dma_memcpy - try to use DMA to do a mem copy which will be
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 *		much faster than CPU mem copy
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 *
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 * @dst - destination pointer
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 * @src - souce pointer
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 * @len - data length to be copied
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 * @return - on successful transfer returns no of bytes
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	     transferred and on failure return error code.
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 */
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int dma_memcpy(void *dst, void *src, size_t len);
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#endif	/* _DMA_H_ */
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