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>

3 files changed, 11 insertions, 2 deletions

diff --git a/arch/arm/plat-samsung/dma-ops.c b/arch/arm/plat-samsung/dma-ops.c
index 889c2c22325..2cded872f22 100644
--- a/arch/arm/plat-samsung/dma-ops.c
+++ b/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));
diff --git a/arch/arm/plat-samsung/include/plat/dma-ops.h b/arch/arm/plat-samsung/include/plat/dma-ops.h
index 4c1a363526c..22eafc310bd 100644
--- a/arch/arm/plat-samsung/include/plat/dma-ops.h
+++ b/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 {
diff --git a/arch/arm/plat-samsung/include/plat/dma-pl330.h b/arch/arm/plat-samsung/include/plat/dma-pl330.h
index 2e55e595867..c5eaad529de 100644
--- a/arch/arm/plat-samsung/include/plat/dma-pl330.h
+++ b/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,