Commit 689379c2 authored by Baolin Wang's avatar Baolin Wang Committed by Vinod Koul
Browse files

dmaengine: sprd: Fix the DMA link-list configuration 



For the Spreadtrum DMA link-list mode, when the DMA engine got a slave
hardware request, which will trigger the DMA engine to load the DMA
configuration from the link-list memory automatically. But before the
slave hardware request, the slave will get an incorrect residue due
to the first node used to trigger the link-list was configured as the
last source address and destination address.

Thus we should make sure the first node was configured the start source
address and destination address, which can fix this issue.

Fixes: 4ac69546 ("dmaengine: sprd: Support DMA link-list mode")
Signed-off-by: default avatarBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/77868edb7aff9d5cb12ac3af8827ef2e244441a6.1567150471.git.baolin.wang@linaro.org


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 962411b0

drivers/dma/sprd-dma.c

+8 −2
Original line number Original line Diff line number Diff line
@@ -908,6 +908,7 @@ sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, 
	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);

	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);

	struct dma_slave_config *slave_cfg = &schan->slave_cfg;

	struct dma_slave_config *slave_cfg = &schan->slave_cfg;

	dma_addr_t src = 0, dst = 0;

	dma_addr_t src = 0, dst = 0;

	dma_addr_t start_src = 0, start_dst = 0;

	struct sprd_dma_desc *sdesc;

	struct sprd_dma_desc *sdesc;

	struct scatterlist *sg;

	struct scatterlist *sg;

	u32 len = 0;

	u32 len = 0;
@@ -954,6 +955,11 @@ sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, 
			dst = sg_dma_address(sg);

			dst = sg_dma_address(sg);

		}

		}





		if (!i) {

			start_src = src;

			start_dst = dst;

		}



		/*

		/*

		 * The link-list mode needs at least 2 link-list

		 * The link-list mode needs at least 2 link-list

		 * configurations. If there is only one sg, it doesn't

		 * configurations. If there is only one sg, it doesn't
@@ -970,8 +976,8 @@ sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, 
		}

		}

	}

	}





	ret = sprd_dma_fill_desc(chan, &sdesc->chn_hw, 0, 0, src, dst, len,

	ret = sprd_dma_fill_desc(chan, &sdesc->chn_hw, 0, 0, start_src,

				 dir, flags, slave_cfg);

				 start_dst, len, dir, flags, slave_cfg);

	if (ret) {

	if (ret) {

		kfree(sdesc);

		kfree(sdesc);

		return NULL;

		return NULL;

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