From 29cf37fa6dd9c4de81b745ad3ae77f3709931d1e Mon Sep 17 00:00:00 2001 From: Adrian Larumbe Date: Mon, 1 Nov 2021 18:08:25 +0000 Subject: [PATCH] dmaengine: Add consumer for the new DMA_MEMCPY_SG API function. This new CDMA binding for device_prep_dma_memcpy_sg was partially borrowed from xlnx kernel tree, an expanded with extended address space support when linking descriptor segments and checking for incorrect zero transfer size. Signed-off-by: Adrian Larumbe Link: https://lore.kernel.org/r/20211101180825.241048-4-adrianml@alumnos.upm.es Signed-off-by: Vinod Koul --- drivers/dma/xilinx/xilinx_dma.c | 122 ++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index 4677ce08ed40..61618148f9d4 100644 --- a/drivers/dma/xilinx/xilinx_dma.c +++ b/drivers/dma/xilinx/xilinx_dma.c @@ -2127,6 +2127,126 @@ xilinx_cdma_prep_memcpy(struct dma_chan *dchan, dma_addr_t dma_dst, return NULL; } +/** + * xilinx_cdma_prep_memcpy_sg - prepare descriptors for a memcpy_sg transaction + * @dchan: DMA channel + * @dst_sg: Destination scatter list + * @dst_sg_len: Number of entries in destination scatter list + * @src_sg: Source scatter list + * @src_sg_len: Number of entries in source scatter list + * @flags: transfer ack flags + * + * Return: Async transaction descriptor on success and NULL on failure + */ +static struct dma_async_tx_descriptor *xilinx_cdma_prep_memcpy_sg( + struct dma_chan *dchan, struct scatterlist *dst_sg, + unsigned int dst_sg_len, struct scatterlist *src_sg, + unsigned int src_sg_len, unsigned long flags) +{ + struct xilinx_dma_chan *chan = to_xilinx_chan(dchan); + struct xilinx_dma_tx_descriptor *desc; + struct xilinx_cdma_tx_segment *segment, *prev = NULL; + struct xilinx_cdma_desc_hw *hw; + size_t len, dst_avail, src_avail; + dma_addr_t dma_dst, dma_src; + + if (unlikely(dst_sg_len == 0 || src_sg_len == 0)) + return NULL; + + if (unlikely(!dst_sg || !src_sg)) + return NULL; + + desc = xilinx_dma_alloc_tx_descriptor(chan); + if (!desc) + return NULL; + + dma_async_tx_descriptor_init(&desc->async_tx, &chan->common); + desc->async_tx.tx_submit = xilinx_dma_tx_submit; + + dst_avail = sg_dma_len(dst_sg); + src_avail = sg_dma_len(src_sg); + /* + * loop until there is either no more source or no more destination + * scatterlist entry + */ + while (true) { + len = min_t(size_t, src_avail, dst_avail); + len = min_t(size_t, len, chan->xdev->max_buffer_len); + if (len == 0) + goto fetch; + + /* Allocate the link descriptor from DMA pool */ + segment = xilinx_cdma_alloc_tx_segment(chan); + if (!segment) + goto error; + + dma_dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - + dst_avail; + dma_src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - + src_avail; + hw = &segment->hw; + hw->control = len; + hw->src_addr = dma_src; + hw->dest_addr = dma_dst; + if (chan->ext_addr) { + hw->src_addr_msb = upper_32_bits(dma_src); + hw->dest_addr_msb = upper_32_bits(dma_dst); + } + + if (prev) { + prev->hw.next_desc = segment->phys; + if (chan->ext_addr) + prev->hw.next_desc_msb = + upper_32_bits(segment->phys); + } + + prev = segment; + dst_avail -= len; + src_avail -= len; + list_add_tail(&segment->node, &desc->segments); + +fetch: + /* Fetch the next dst scatterlist entry */ + if (dst_avail == 0) { + if (dst_sg_len == 0) + break; + dst_sg = sg_next(dst_sg); + if (dst_sg == NULL) + break; + dst_sg_len--; + dst_avail = sg_dma_len(dst_sg); + } + /* Fetch the next src scatterlist entry */ + if (src_avail == 0) { + if (src_sg_len == 0) + break; + src_sg = sg_next(src_sg); + if (src_sg == NULL) + break; + src_sg_len--; + src_avail = sg_dma_len(src_sg); + } + } + + if (list_empty(&desc->segments)) { + dev_err(chan->xdev->dev, + "%s: Zero-size SG transfer requested\n", __func__); + goto error; + } + + /* Link the last hardware descriptor with the first. */ + segment = list_first_entry(&desc->segments, + struct xilinx_cdma_tx_segment, node); + desc->async_tx.phys = segment->phys; + prev->hw.next_desc = segment->phys; + + return &desc->async_tx; + +error: + xilinx_dma_free_tx_descriptor(chan, desc); + return NULL; +} + /** * xilinx_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction * @dchan: DMA channel @@ -3115,7 +3235,9 @@ static int xilinx_dma_probe(struct platform_device *pdev) DMA_RESIDUE_GRANULARITY_SEGMENT; } else if (xdev->dma_config->dmatype == XDMA_TYPE_CDMA) { dma_cap_set(DMA_MEMCPY, xdev->common.cap_mask); + dma_cap_set(DMA_MEMCPY_SG, xdev->common.cap_mask); xdev->common.device_prep_dma_memcpy = xilinx_cdma_prep_memcpy; + xdev->common.device_prep_dma_memcpy_sg = xilinx_cdma_prep_memcpy_sg; /* Residue calculation is supported by only AXI DMA and CDMA */ xdev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;