omap: dma: Support for prefetch in destination synchronizedtransfer
Omap DMA controller can prefetch data in advance in case of
destination synchronized data transfer. This may increase
performance when target HW block doesn't have fifo.
Data is waiting for transfer request in DMA fifo instead of read from memory.
Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index f7f571e..ec7eddf 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -290,7 +290,7 @@
val = dma_read(CCR(lch));
/* DMA_SYNCHRO_CONTROL_UPPER depends on the channel number */
- val &= ~((3 << 19) | 0x1f);
+ val &= ~((1 << 23) | (3 << 19) | 0x1f);
val |= (dma_trigger & ~0x1f) << 14;
val |= dma_trigger & 0x1f;
@@ -304,11 +304,14 @@
else
val &= ~(1 << 18);
- if (src_or_dst_synch)
- val |= 1 << 24; /* source synch */
- else
+ if (src_or_dst_synch == OMAP_DMA_DST_SYNC_PREFETCH) {
val &= ~(1 << 24); /* dest synch */
-
+ val |= (1 << 23); /* Prefetch */
+ } else if (src_or_dst_synch) {
+ val |= 1 << 24; /* source synch */
+ } else {
+ val &= ~(1 << 24); /* dest synch */
+ }
dma_write(val, CCR(lch));
}