[RFC 25/34] dmaengine: PL08x: start next descriptor from irq context
From: Russell King <hidden>
Date: 2012-05-29 09:43:40
Subsystem:
dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
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. Signed-off-by: Russell King <redacted> --- drivers/dma/amba-pl08x.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 4788ec0..1118fc0 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c@@ -1661,10 +1661,7 @@ static void pl08x_tasklet(unsigned long data) 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
@@ -1776,6 +1773,10 @@ static irqreturn_t pl08x_irq(int irq, void *dev) 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);
--
1.7.4.4