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Peng Mavinodkoul
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dmaengine: fsl-qdma: fix SoC may hang on 16 byte unaligned read
There is chip (ls1028a) errata: The SoC may hang on 16 byte unaligned read transactions by QDMA. Unaligned read transactions initiated by QDMA may stall in the NOC (Network On-Chip), causing a deadlock condition. Stalled transactions will trigger completion timeouts in PCIe controller. Workaround: Enable prefetch by setting the source descriptor prefetchable bit ( SD[PF] = 1 ). Implement this workaround. Cc: stable@vger.kernel.org Fixes: b092529 ("dmaengine: fsl-qdma: Add qDMA controller driver for Layerscape SoCs") Signed-off-by: Peng Ma <peng.ma@nxp.com> Signed-off-by: Frank Li <Frank.Li@nxp.com> Link: https://lore.kernel.org/r/20240201215007.439503-1-Frank.Li@nxp.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
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drivers/dma/fsl-qdma.c

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -109,6 +109,7 @@
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#define FSL_QDMA_CMD_WTHROTL_OFFSET 20
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#define FSL_QDMA_CMD_DSEN_OFFSET 19
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#define FSL_QDMA_CMD_LWC_OFFSET 16
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#define FSL_QDMA_CMD_PF BIT(17)
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/* Field definition for Descriptor status */
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#define QDMA_CCDF_STATUS_RTE BIT(5)
@@ -384,7 +385,8 @@ static void fsl_qdma_comp_fill_memcpy(struct fsl_qdma_comp *fsl_comp,
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qdma_csgf_set_f(csgf_dest, len);
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/* Descriptor Buffer */
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cmd = cpu_to_le32(FSL_QDMA_CMD_RWTTYPE <<
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FSL_QDMA_CMD_RWTTYPE_OFFSET);
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FSL_QDMA_CMD_RWTTYPE_OFFSET) |
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FSL_QDMA_CMD_PF;
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sdf->data = QDMA_SDDF_CMD(cmd);
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cmd = cpu_to_le32(FSL_QDMA_CMD_RWTTYPE <<

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