linux-kernel - [PATCH v2 05/15] dmaengine: omap-dma: Add support for no

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Date:	Thu, 13 Sep 2012 16:37:55 +0300
From:	Peter Ujfalusi <peter.ujfalusi@...com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Liam Girdwood <lrg@...com>, Tony Lindgren <tony@...mide.com>,
	Russell King <rmk+kernel@....linux.org.uk>,
	Vinod Koul <vinod.koul@...el.com>, Dan Williams <djbw@...com>,
	Jarkko Nikula <jarkko.nikula@...mer.com>
Cc:	alsa-devel@...a-project.org, linux-omap@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Janusz Krzysztofik <jkrzyszt@....icnet.pl>,
	Ricardo Neri <ricardo.neri@...com>,
	Lars-Peter Clausen <lars@...afoo.de>
Subject: [PATCH v2 05/15] dmaengine: omap-dma: Add support for no_wakeup in cyclic mode

When requested disable all DMA interrupts for the channel. In this mode
user space does not expect periodic reports from kernel about the progress
of the audio stream - PulseAudio for example support this type of mode.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
CC: Russell King <rmk+kernel@....linux.org.uk>
---
 drivers/dma/omap-dma.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index c6a711d..cbe087e 100644
--- a/drivers/dma/omap-dma.c
+++ b/drivers/dma/omap-dma.c
@@ -374,6 +374,7 @@ static struct dma_async_tx_descriptor *omap_dma_prep_dma_cyclic(
 	struct omap_desc *d;
 	dma_addr_t dev_addr;
 	unsigned es, sync_type;
+	unsigned long tx_flags = 0;
 	u32 burst;
 
 	if (dir == DMA_DEV_TO_MEM) {
@@ -429,7 +430,11 @@ static struct dma_async_tx_descriptor *omap_dma_prep_dma_cyclic(
 	if (!c->cyclic) {
 		c->cyclic = true;
 		omap_dma_link_lch(c->dma_ch, c->dma_ch);
-		omap_enable_dma_irq(c->dma_ch, OMAP_DMA_FRAME_IRQ);
+
+		if (!no_wakeup) {
+			omap_enable_dma_irq(c->dma_ch, OMAP_DMA_FRAME_IRQ);
+			tx_flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
+		}
 		omap_disable_dma_irq(c->dma_ch, OMAP_DMA_BLOCK_IRQ);
 	}
 
@@ -438,7 +443,7 @@ static struct dma_async_tx_descriptor *omap_dma_prep_dma_cyclic(
 		omap_set_dma_dest_burst_mode(c->dma_ch, OMAP_DMA_DATA_BURST_16);
 	}
 
-	return vchan_tx_prep(&c->vc, &d->vd, DMA_CTRL_ACK | DMA_PREP_INTERRUPT);
+	return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
 }
 
 static int omap_dma_slave_config(struct omap_chan *c, struct dma_slave_config *cfg)
-- 
1.7.12

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