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dmaengine: fsl-edma: fix edma4 channel enable failure on second attempt

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When attempting to start DMA for the second time using
fsl_edma3_enable_request(), channel never start.

CHn_MUX must have a unique value when selecting a peripheral slot in the
channel mux configuration. The only value that may overlap is source 0.
If there is an attempt to write a mux configuration value that is already
consumed by another channel, a mux configuration of 0 (SRC = 0) will be
written.

Check CHn_MUX before writing in fsl_edma3_enable_request().

Fixes: 72f5801a4e2b ("dmaengine: fsl-edma: integrate v3 support")
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20230823182635.2618118-1-Frank.Li@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Frank Li 2023-08-23 14:26:35 -04:00 committed by Vinod Koul
parent 54a5aff6f9
commit 3f4b82167a
1 changed files with 8 additions and 2 deletions
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10
drivers/dma/fsl-edma-common.c
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@ -92,8 +92,14 @@ static void fsl_edma3_enable_request(struct fsl_edma_chan *fsl_chan)
edma_writel_chreg(fsl_chan, val, ch_sbr);
if (flags & FSL_EDMA_DRV_HAS_CHMUX)
edma_writel_chreg(fsl_chan, fsl_chan->srcid, ch_mux);
if (flags & FSL_EDMA_DRV_HAS_CHMUX) {
/*
* ch_mux: With the exception of 0, attempts to write a value
* already in use will be forced to 0.
*/
if (!edma_readl_chreg(fsl_chan, ch_mux))
edma_writel_chreg(fsl_chan, fsl_chan->srcid, ch_mux);
}
val = edma_readl_chreg(fsl_chan, ch_csr);
val |= EDMA_V3_CH_CSR_ERQ;