ARM: SAMSUNG: Add device tree support for pl330 dma engine wrappers

A new dma request id 'DMACH_DT_PROP' is introduced for client drivers
requesting a dma channel. This request indicates that a device tree
node property represting the dma channel is available in
'struct samsung_dma_info'. The dma channel request wrapper uses the
node property value as the value for the filter parameter.
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-samsung/dma-ops.c

@@ -24,11 +24,18 @@ static unsigned samsung_dmadev_request(enum dma_ch dma_ch,
 	struct dma_chan *chan;
 	dma_cap_mask_t mask;
 	struct dma_slave_config slave_config;
+	void *filter_param;
 
 	dma_cap_zero(mask);
 	dma_cap_set(info->cap, mask);
 
-	chan = dma_request_channel(mask, pl330_filter, (void *)dma_ch);
+	/*
+	 * If a dma channel property of a device node from device tree is
+	 * specified, use that as the fliter parameter.
+	 */
+	filter_param = (dma_ch == DMACH_DT_PROP) ? (void *)info->dt_dmach_prop :
+				(void *)dma_ch;
+	chan = dma_request_channel(mask, pl330_filter, filter_param);
 
 	if (info->direction == DMA_FROM_DEVICE) {
 		memset(&slave_config, 0, sizeof(struct dma_slave_config));

arch/arm/plat-samsung/include/plat/dma-ops.h

@@ -31,6 +31,7 @@ struct samsung_dma_info {
 	enum dma_slave_buswidth width;
 	dma_addr_t fifo;
 	struct s3c2410_dma_client *client;
+	struct property *dt_dmach_prop;
 };
 
 struct samsung_dma_ops {

arch/arm/plat-samsung/include/plat/dma-pl330.h

@@ -21,7 +21,8 @@
  * use these just as IDs.
  */
 enum dma_ch {
-	DMACH_UART0_RX,
+	DMACH_DT_PROP = -1,
+	DMACH_UART0_RX = 0,
 	DMACH_UART0_TX,
 	DMACH_UART1_RX,
 	DMACH_UART1_TX,