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dmaengine: Add consumer for the new DMA_MEMCPY_SG API function.

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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 <adrianml@alumnos.upm.es>
Link: https://lore.kernel.org/r/20211101180825.241048-4-adrianml@alumnos.upm.es
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Adrian Larumbe 2021-11-01 18:08:25 +00:00 committed by Vinod Koul
parent 3218910fd5
commit 29cf37fa6d
1 changed files with 122 additions and 0 deletions
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122
drivers/dma/xilinx/xilinx_dma.c
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@ -2127,6 +2127,126 @@ error:
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;