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dma: dma-axi-dmac: fix SW cyclic transfers

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If 'hw_cyclic' is false we should still be able to do cyclic transfers in
"software". That was not working for the case where 'desc->num_sgs' is 1
because 'chan->next_desc' is never set with the current desc which means
that the cyclic transfer only runs once and in the next SOT interrupt we
do nothing since vchan_next_desc() will return NULL.

Fix it by setting 'chan->next_desc' as soon as we get a new desc via
vchan_next_desc().

Fixes: 0e3b67b348 ("dmaengine: Add support for the Analog Devices AXI-DMAC DMA controller")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
base-commit: 3980351785
change-id: 20251104-axi-dmac-fixes-and-improvs-e3ad512a329c
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Link: https://patch.msgid.link/20251104-axi-dmac-fixes-and-improvs-v1-1-3e6fd9328f72@analog.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Nuno Sá 2025-11-04 16:22:25 +00:00 committed by Vinod Koul
parent c3af05623e
commit 9bd257181f
1 changed files with 1 additions and 2 deletions
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3
drivers/dma/dma-axi-dmac.c
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@ -247,6 +247,7 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
return;
list_move_tail(&vdesc->node, &chan->active_descs);
desc = to_axi_dmac_desc(vdesc);
chan->next_desc = desc;
}
sg = &desc->sg[desc->num_submitted];
@ -265,8 +266,6 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
else
chan->next_desc = NULL;
flags |= AXI_DMAC_FLAG_LAST;
} else {
chan->next_desc = desc;
}
sg->hw->id = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_ID);