linux-kernel - [PATCH] dmaengine: fsl-edma: fix channel parameter config for fixed channel requests

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Message-Id: <20250917-b4-edma-chanconf-v1-1-886486e02e91@nxp.com>
Date: Wed, 17 Sep 2025 17:53:42 +0800
From: Joy Zou <joy.zou@....com>
To: Frank Li <Frank.Li@....com>, Vinod Koul <vkoul@...nel.org>
Cc: imx@...ts.linux.dev, dmaengine@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Joy Zou <joy.zou@....com>, 
 stable@...r.kernel.org
Subject: [PATCH] dmaengine: fsl-edma: fix channel parameter config for
 fixed channel requests

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@....com>
Cc: stable@...r.kernel.org
---
 drivers/dma/fsl-edma-main.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/dma/fsl-edma-main.c b/drivers/dma/fsl-edma-main.c
index 97583c7d51a2e8e7a50c7eb4f5ff0582ac95798d..f0c1a2a3fd26e663b3f0b918ff979a68af510fbf 100644
--- a/drivers/dma/fsl-edma-main.c
+++ b/drivers/dma/fsl-edma-main.c
@@ -317,10 +317,8 @@ static struct dma_chan *fsl_edma3_xlate(struct of_phandle_args *dma_spec,
 			return NULL;
 		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;
@@ -328,17 +326,15 @@ static struct dma_chan *fsl_edma3_xlate(struct of_phandle_args *dma_spec,
 		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;
 }

---
base-commit: 05af764719214d6568adb55c8749dec295228da8
change-id: 20250917-b4-edma-chanconf-da616503f29f

Best regards,
-- 
Joy Zou <joy.zou@....com>