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-goucem@xxxxxx> Acked-by: Venkatraman S <svenkatr@xxxxxx> Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> Acked-by: Shilpa Maddi <s-maddi@xxxxxx> --- 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 majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
