spi/ep93xx: add DMA support

This patch adds DMA support for the EP93xx SPI driver. By default the DMA is
not enabled but it can be enabled by setting ep93xx_spi_info.use_dma to true
in board configuration file.

Note that the SPI driver still uses PIO for small transfers (<= 8 bytes) for
performance reasons.

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 7 insertions, 1 deletions

diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c
index 82079545adc4..cc9f1d4b104d 100644
--- a/arch/arm/mach-ep93xx/core.c
+++ b/arch/arm/mach-ep93xx/core.c
@@ -488,11 +488,15 @@ static struct resource ep93xx_spi_resources[] = {
         },
 };
 
+static u64 ep93xx_spi_dma_mask = DMA_BIT_MASK(32);
+
 static struct platform_device ep93xx_spi_device = {
         .name           = "ep93xx-spi",
         .id             = 0,
         .dev            = {
-                .platform_data = &ep93xx_spi_master_data,
+                .platform_data          = &ep93xx_spi_master_data,
+                .coherent_dma_mask      = DMA_BIT_MASK(32),
+                .dma_mask               = &ep93xx_spi_dma_mask,
         },
         .num_resources  = ARRAY_SIZE(ep93xx_spi_resources),
         .resource       = ep93xx_spi_resources,
diff --git a/arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h b/arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h
index 0a37961b3453..9bb63ac13f04 100644
--- a/arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h
+++ b/arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h
@@ -7,9 +7,11 @@ struct spi_device;
  * struct ep93xx_spi_info - EP93xx specific SPI descriptor
  * @num_chipselect: number of chip selects on this board, must be
  *                  at least one
+ * @use_dma: use DMA for the transfers
  */
 struct ep93xx_spi_info {
         int     num_chipselect;
+        bool    use_dma;
 };
 
 /**