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dmaengine: axi-dmac: Only use hardware cyclic mode for single segment transfers

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In hardware cyclic mode the submitted segment is repeated. This means
hardware cyclic mode can only be used if the transfer has a single segment.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Lars-Peter Clausen 2017-09-05 10:16:37 +02:00 committed by Vinod Koul
parent 2bd6bf03f4
commit 63ab76dbbd
1 changed files with 4 additions and 2 deletions
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6
drivers/dma/dma-axi-dmac.c
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@ -220,9 +220,11 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
/*
* If the hardware supports cyclic transfers and there is no callback to
* call, enable hw cyclic mode to avoid unnecessary interrupts.
* call and only a single segment, enable hw cyclic mode to avoid
* unnecessary interrupts.
*/
if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback)
if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback &&
desc->num_sgs == 1)
flags |= AXI_DMAC_FLAG_CYCLIC;
axi_dmac_write(dmac, AXI_DMAC_REG_X_LENGTH, sg->x_len - 1);