Commit 3218910f authored by Adrian Larumbe's avatar Adrian Larumbe Committed by Vinod Koul
Browse files

dmaengine: Add core function and capability check for DMA_MEMCPY_SG 



This is the old DMA_SG interface that was removed in commit
c678fa66 ("dmaengine: remove DMA_SG as it is dead code in kernel"). It
has been renamed to DMA_MEMCPY_SG to better match the MEMSET and MEMSET_SG
naming convention.

It should only be used for mem2mem copies, either main system memory or
CPU-addressable device memory (like video memory on a PCI graphics card).

Bringing back this interface was prompted by the need to use the Xilinx
CDMA device for mem2mem SG transfers.

Signed-off-by: default avatarAdrian Larumbe <adrianml@alumnos.upm.es>
Link: https://lore.kernel.org/r/20211101180825.241048-3-adrianml@alumnos.upm.es


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 58fe1076

drivers/dma/dmaengine.c

+7 −0
Original line number Diff line number Diff line
@@ -1159,6 +1159,13 @@ int dma_async_device_register(struct dma_device *device) 
		return -EIO;

	}



	if (dma_has_cap(DMA_MEMCPY_SG, device->cap_mask) && !device->device_prep_dma_memcpy_sg) {

		dev_err(device->dev,

			"Device claims capability %s, but op is not defined\n",

			"DMA_MEMCPY_SG");

		return -EIO;

	}



	if (dma_has_cap(DMA_XOR, device->cap_mask) && !device->device_prep_dma_xor) {

		dev_err(device->dev,

			"Device claims capability %s, but op is not defined\n",

include/linux/dmaengine.h

+20 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ enum dma_status { 
 */

enum dma_transaction_type {

	DMA_MEMCPY,

	DMA_MEMCPY_SG,

	DMA_XOR,

	DMA_PQ,

	DMA_XOR_VAL,
@@ -891,6 +892,11 @@ struct dma_device { 
	struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)(

		struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,

		size_t len, unsigned long flags);

	struct dma_async_tx_descriptor *(*device_prep_dma_memcpy_sg)(

		struct dma_chan *chan,

		struct scatterlist *dst_sg, unsigned int dst_nents,

		struct scatterlist *src_sg, unsigned int src_nents,

		unsigned long flags);

	struct dma_async_tx_descriptor *(*device_prep_dma_xor)(

		struct dma_chan *chan, dma_addr_t dst, dma_addr_t *src,

		unsigned int src_cnt, size_t len, unsigned long flags);
@@ -1051,6 +1057,20 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy( 
						    len, flags);

}



static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy_sg(

		struct dma_chan *chan,

		struct scatterlist *dst_sg, unsigned int dst_nents,

		struct scatterlist *src_sg, unsigned int src_nents,

		unsigned long flags)

{

	if (!chan || !chan->device || !chan->device->device_prep_dma_memcpy_sg)

		return NULL;



	return chan->device->device_prep_dma_memcpy_sg(chan, dst_sg, dst_nents,

						       src_sg, src_nents,

						       flags);

}



static inline bool dmaengine_is_metadata_mode_supported(struct dma_chan *chan,

		enum dma_desc_metadata_mode mode)

{