Commit e28d9155 authored Jun 06, 2019 by Alexandru Ardelean Committed by Vinod Koul Jun 14, 2019

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



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>

parent e3923592

drivers/dma/dma-axi-dmac.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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;

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