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@xxxxxxxxxx>
---
drivers/dma/dma-axi-dmac.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index e0702697e2b3..3b418d545c7a 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -97,6 +97,7 @@ 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;
@@ -221,7 +222,8 @@ 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
@@ -295,6 +297,7 @@ 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;
--
2.20.1
