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Fix two more RP1 DMA bugs #6734

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Merged
pelwell merged 2 commits into from
Mar 20, 2025
Merged

Fix two more RP1 DMA bugs #6734

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dcfccd0
dmaengine: dw-axi-dmac: Improve axi_desc_put
pelwell Mar 20, 2025
1456eb0
dmaengine: dw-axi-dmac: Fix alignment checks
pelwell Mar 20, 2025
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13 changes: 7 additions & 6 deletions drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
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Original file line number Diff line number Diff line change
Expand Up @@ -367,7 +367,8 @@ static void axi_desc_put(struct axi_dma_desc *desc)

for (descs_put = 0; descs_put < count; descs_put++) {
hw_desc = &desc->hw_desc[descs_put];
dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
if (hw_desc->lli)
dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
}

kfree(desc->hw_desc);
Expand Down Expand Up @@ -749,11 +750,6 @@ static int dw_axi_dma_set_hw_desc(struct axi_dma_chan *chan,

mem_width = __ffs(data_width | mem_addr | len);

if (!IS_ALIGNED(mem_addr, 4)) {
dev_err(chan->chip->dev, "invalid buffer alignment\n");
return -EINVAL;
}

/* Use a reasonable upper limit otherwise residue reporting granularity grows large */
mem_burst_msize = axi_dma_encode_msize(16);

Expand Down Expand Up @@ -798,6 +794,11 @@ static int dw_axi_dma_set_hw_desc(struct axi_dma_chan *chan,
return -EINVAL;
}

if (len % reg_width) {
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@P33M P33M Mar 20, 2025

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(Thinking aloud, not an issue at the moment) I wonder if use-cases that have memory buffers spanning a page boundary with odd alignment are broken when using this driver - and this error message makes this case known.

But fixing this means rewriting dw_axi_dma_chan_prep_[cyclic|slave]_sg to dynamically allocate hardware descriptors inside for_each_sg().

dev_err(chan->chip->dev, "length not aligned to device width\n");
return -EINVAL;
}

if (block_ts > axi_block_ts)
return -EINVAL;

Expand Down