dmaengine: PL08x: start next descriptor from irq context
Rather than waiting for the tasklet to run, we can start the next
descriptor from interrupt context, as soon as we know that the
previous descriptor has completed.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index b613284..30b6921 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -1671,10 +1671,7 @@
spin_lock_irqsave(&plchan->lock, flags);
list_splice_tail_init(&plchan->done_list, &head);
- /* If a new descriptor is queued, set it up plchan->at is NULL here */
- if (!list_empty(&plchan->issued_list)) {
- pl08x_start_next_txd(plchan);
- } else if (!list_empty(&plchan->pend_list) || plchan->phychan_hold) {
+ if (plchan->at || !list_empty(&plchan->pend_list) || plchan->phychan_hold) {
/*
* This channel is still in use - we have a new txd being
* prepared and will soon be queued. Don't give up the
@@ -1786,6 +1783,10 @@
pl08x_release_mux(plchan);
dma_cookie_complete(&tx->tx);
list_add_tail(&tx->node, &plchan->done_list);
+
+ /* And start the next descriptor */
+ if (!list_empty(&plchan->issued_list))
+ pl08x_start_next_txd(plchan);
}
spin_unlock(&plchan->lock);