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Subject[PATCH v3 11/12] dma: edma: Keep tracking of Pending interrupts (pending_acks)
Date
The total_processed variable was being used to keep track of when
DMA is completed for a particular descriptor.

This doesn't work anymore, as the interrupt for completion can come
in much later than when the total_processed variable is updated to
reflect that all SG entries have been issues. Introduce another
variable that reflects the actual value. This will serve a purpose
different from what total_processed was required to help with.

Also add code that give special treatment for the first linked set
interrupt as pending_acks is handled a bit differently for that case.

Signed-off-by: Joel Fernandes <joelf@ti.com>
---
drivers/dma/edma.c | 32 +++++++++++++++++++++++++++++---
1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 061f0cf..eca1b47 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -59,6 +59,10 @@ struct edma_desc {
int pset_nr;
int total_processed;
int next_setup_linkset;
+
+ int no_first_ls_ack;
+ int pending_acks;
+
struct edmacc_param pset[0];
};

@@ -147,8 +151,7 @@ static void edma_execute(struct edma_chan *echan)
struct edmacc_param tmp_param;

/* If either we processed all psets or we're still not started */
- if (!echan->edesc ||
- echan->edesc->pset_nr == echan->edesc->total_processed) {
+ if (!echan->edesc || !echan->edesc->pending_acks) {
/* Get next vdesc */
vdesc = vchan_next_desc(&echan->vchan);
if (!vdesc) {
@@ -180,6 +183,8 @@ static void edma_execute(struct edma_chan *echan)

edesc->total_processed += total_link_set;

+ edesc->pending_acks += total_link_set;
+
total_left = edesc->pset_nr - edesc->total_processed;

total_link_set = total_left > MAX_NR_LS ?
@@ -190,6 +195,8 @@ static void edma_execute(struct edma_chan *echan)
where total pset_nr is strictly within MAX_NR size */
if (total_left > total_link_set)
edma_enable_interrupt(echan->slot[i]);
+ else
+ edesc->no_first_ls_ack = 1;

/* Setup link between linked set 0 to set 1 */
edma_link(echan->slot[i], echan->slot[i+1]);
@@ -210,6 +217,9 @@ static void edma_execute(struct edma_chan *echan)
}

edesc->total_processed += total_link_set;
+
+ edesc->pending_acks += total_link_set;
+
total_left = edesc->pset_nr - edesc->total_processed;

if (total_left)
@@ -267,6 +277,8 @@ static void edma_execute(struct edma_chan *echan)

edesc->total_processed += total_link_set;

+ edesc->pending_acks += total_link_set;
+
slot_off = total_link_set + ls_cur_off - 1;

if (edesc->total_processed == edesc->pset_nr)
@@ -498,8 +510,22 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)

edesc = echan->edesc;

+ if (edesc->pending_acks < MAX_NR_LS)
+ edesc->pending_acks = 0;
+ else
+ edesc->pending_acks -= MAX_NR_LS;
+
+ if (edesc->no_first_ls_ack) {
+ if (edesc->pending_acks < MAX_NR_LS)
+ edesc->pending_acks = 0;
+ else
+ edesc->pending_acks -= MAX_NR_LS;
+
+ edesc->no_first_ls_ack = 0;
+ }
+
if (edesc) {
- if (edesc->total_processed == edesc->pset_nr) {
+ if (!edesc->pending_acks) {
dev_dbg(dev, "Transfer complete,"
" stopping channel %d\n", ch_num);
edma_stop(echan->ch_num);
--
1.7.9.5


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