From: Russell King Date: Fri, 25 May 2012 14:41:13 +0000 (+0100) Subject: dmaengine: PL08x: start next descriptor from irq context X-Git-Tag: firefly_0821_release~3680^2~2269^2^2~9 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c33b644cb31899265ec5102a4ed45c44269dde95;p=firefly-linux-kernel-4.4.55.git 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 Tested-by: Linus Walleij Signed-off-by: Russell King --- diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index b6132845e65c..30b6921f094f 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -1671,10 +1671,7 @@ 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 @@ -1786,6 +1783,10 @@ 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);