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dmaengine: omap-dma: move barrier to omap_dma_start_desc() 

We don't need to issue a barrier for every segment of a DMA transfer;
doing this just once per descriptor will do.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2013-11-06 17:15:16 +00:00
parent 965aeb4df1
commit 5987190270
1 changed files with 7 additions and 1 deletions
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8
drivers/dma/omap-dma.c
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@ -195,7 +195,6 @@ static void omap_dma_start(struct omap_chan *c, struct omap_desc *d)
val = c->plat->dma_read(CCR, c->dma_ch); val = c->plat->dma_read(CCR, c->dma_ch);
val |= CCR_ENABLE; val |= CCR_ENABLE;
mb();
c->plat->dma_write(val, CCR, c->dma_ch); c->plat->dma_write(val, CCR, c->dma_ch);
} }
@ -301,6 +300,13 @@ static void omap_dma_start_desc(struct omap_chan *c)
c->desc = d = to_omap_dma_desc(&vd->tx); c->desc = d = to_omap_dma_desc(&vd->tx);
c->sgidx = 0; c->sgidx = 0;
/*
* This provides the necessary barrier to ensure data held in
* DMA coherent memory is visible to the DMA engine prior to
* the transfer starting.
*/
mb();
c->plat->dma_write(d->ccr, CCR, c->dma_ch); c->plat->dma_write(d->ccr, CCR, c->dma_ch);
if (dma_omap1()) if (dma_omap1())
c->plat->dma_write(d->ccr >> 16, CCR2, c->dma_ch); c->plat->dma_write(d->ccr >> 16, CCR2, c->dma_ch);