System DMA packet synchronisation is currently not supported in the
Linux Kernel.
This patch provides necessary modifications to support packet
synchronisation:
Function omap_set_dma_transfer_params() handles value OMAP_DMA_SYNC_PACKET
to program FS and BS bits of register CCR.
Users can give the packet size to the DMA driver by using parameters
src_fi / dst_fi in functions omap_set_dma_src_params() /
omap_set_dma_dest_params().
Patch has been validated using OMAP's McSPI (on Zoom2, OMAP3430):
McSPI is configured to use DMA transfer.
FIFO are activated with a threshold of 16 bytes (i.e. DMA requests will be
triggered as soon as more than 16 bytes are free in the FIFO).
A frame of 132 elements (bytes) has been transfered, by packets of 16
elements. Resulting transfer was 8 packets of 16 elements plus a last packet
of 4 elements.
Modifications tested building on OMAP2, OMAP3 and OMAP4 configurations.
Signed-off-by: Fabrice Goucem <f-gou...@ti.com>
Acked-by: Venkatraman S <svenk...@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilim...@ti.com>
Acked-by: Shilpa Maddi <s-ma...@ti.com>
---
arch/arm/plat-omap/dma.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index 2ab224c..48f9355 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -293,12 +293,14 @@ void omap_set_dma_transfer_params(int lch, int data_type,
int elem_count,
val |= (dma_trigger & ~0x1f) << 14;
val |= dma_trigger & 0x1f;
- if (sync_mode & OMAP_DMA_SYNC_FRAME)
+ if ((sync_mode == OMAP_DMA_SYNC_FRAME) ||
+ (sync_mode == OMAP_DMA_SYNC_PACKET))
val |= 1 << 5;
else
val &= ~(1 << 5);
- if (sync_mode & OMAP_DMA_SYNC_BLOCK)
+ if ((sync_mode == OMAP_DMA_SYNC_BLOCK) ||
+ (sync_mode == OMAP_DMA_SYNC_PACKET))
val |= 1 << 18;
else
val &= ~(1 << 18);
--
1.6.0.4
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
