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dmaengine: axi-dmac: terminate early DMA transfers after a partial one

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When a partial transfer is received, the driver should not submit any more
segments to the hardware, as they will be ignored/unused until a new
transfer start operation is done.

This change implements this by adding a new flag on the AXI DMAC
descriptor. This flags is set to true, if there was a partial transfer in
a previously completed segment. When that flag is true, the TLAST flag is
added to the to the submitted segment, signaling the controller to stop
receiving more segments.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Alexandru Ardelean 2019-06-06 13:45:49 +03:00 committed by Vinod Koul
parent e3923592f8
commit e28d915528
1 changed files with 4 additions and 1 deletions
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5
drivers/dma/dma-axi-dmac.c
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@ -96,6 +96,7 @@ struct axi_dmac_sg {
struct axi_dmac_desc {
struct virt_dma_desc vdesc;
bool cyclic;
bool have_partial_xfer;
unsigned int num_submitted;
unsigned int num_completed;
@ -220,7 +221,8 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
}
desc->num_submitted++;
if (desc->num_submitted == desc->num_sgs) {
if (desc->num_submitted == desc->num_sgs ||
desc->have_partial_xfer) {
if (desc->cyclic)
desc->num_submitted = 0; /* Start again */
else
@ -294,6 +296,7 @@ static void axi_dmac_dequeue_partial_xfers(struct axi_dmac_chan *chan)
if (sg->id == AXI_DMAC_SG_UNUSED)
continue;
if (sg->id == id) {
desc->have_partial_xfer = true;
sg->partial_len = len;
found_sg = true;
break;