From 59871902703c47acc730555be41bd9cb36d3700c Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 6 Nov 2013 17:15:16 +0000 Subject: 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 Acked-by: Vinod Koul Signed-off-by: Russell King --- drivers/dma/omap-dma.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/dma') diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index 49609275b2e..49b303296d7 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -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 |= CCR_ENABLE; - mb(); 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->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); if (dma_omap1()) c->plat->dma_write(d->ccr >> 16, CCR2, c->dma_ch); -- cgit v1.2.3