[PATCH 6.6 156/160] dmaengine: fsl-edma: fix channel parameter config for fixed channel requests

Greg Kroah-Hartman
2026-04-08T18:27:04Z

From: Joy Zou <joy.zou@nxp.com>

[ Upstream commit 2e7b5cf72e51c9cf9c8b75190189c757df31ddd9 ]

Configure only the requested channel when a fixed channel is specified
to avoid modifying other channels unintentionally.

Fix parameter configuration when a fixed DMA channel is requested on
i.MX9 AON domain and i.MX8QM/QXP/DXL platforms. When a client requests
a fixed channel (e.g., channel 6), the driver traverses channels 0-5
and may unintentionally modify their configuration if they are unused.

This leads to issues such as setting the `is_multi_fifo` flag unexpectedly,
causing memcpy tests to fail when using the dmatest tool.

Only affect edma memcpy test when the channel is fixed.

Fixes: 72f5801a4e2b ("dmaengine: fsl-edma: integrate v3 support")
Signed-off-by: Joy Zou <joy.zou@nxp.com>
Cc: stable@vger.kernel.org
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20250917-b4-edma-chanconf-v1-1-886486e02e91@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/dma/fsl-edma-main.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)

--- a/drivers/dma/fsl-edma-main.c
+++ b/drivers/dma/fsl-edma-main.c
@@ -152,10 +152,8 @@ static struct dma_chan *fsl_edma3_xlate(
fsl_chan = to_fsl_edma_chan(chan);
i = fsl_chan - fsl_edma->chans;

- fsl_chan->priority = dma_spec->args[1];
- fsl_chan->is_rxchan = dma_spec->args[2] & FSL_EDMA_RX;
- fsl_chan->is_remote = dma_spec->args[2] & FSL_EDMA_REMOTE;
- fsl_chan->is_multi_fifo = dma_spec->args[2] & FSL_EDMA_MULTI_FIFO;
+ if (!b_chmux && i != dma_spec->args[0])
+ continue;

if ((dma_spec->args[2] & FSL_EDMA_EVEN_CH) && (i & 0x1))
continue;
@@ -163,17 +161,15 @@ static struct dma_chan *fsl_edma3_xlate(
if ((dma_spec->args[2] & FSL_EDMA_ODD_CH) && !(i & 0x1))
continue;

- if (!b_chmux && i == dma_spec->args[0]) {
- chan = dma_get_slave_channel(chan);
- chan->device->privatecnt++;
- return chan;
- } else if (b_chmux && !fsl_chan->srcid) {
- /* if controller support channel mux, choose a free channel */
- chan = dma_get_slave_channel(chan);
- chan->device->privatecnt++;
- fsl_chan->srcid = dma_spec->args[0];
- return chan;
- }
+ fsl_chan->srcid = dma_spec->args[0];
+ fsl_chan->priority = dma_spec->args[1];
+ fsl_chan->is_rxchan = dma_spec->args[2] & FSL_EDMA_RX;
+ fsl_chan->is_remote = dma_spec->args[2] & FSL_EDMA_REMOTE;
+ fsl_chan->is_multi_fifo = dma_spec->args[2] & FSL_EDMA_MULTI_FIFO;
+
+ chan = dma_get_slave_channel(chan);
+ chan->device->privatecnt++;
+ return chan;
}
return NULL;
}