dmaengine/dw_dmac: allow src/dst masters to be configured at runtime

Some platforms have flexible mastering capabilities and this needs
to be selected at runtime. If the platform has specified private
data in the form of the dw_dma_slave then fetch the source and
destination masters from here. If this isn't present, default to
the previous of 0 and 1.

v2: cleanup whitespace
Acked-by: NHans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Signed-off-by: NJamie Iles <jamie.iles@picochip.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dma/dw_dmac.c

@@ -32,15 +32,18 @@
  * which does not support descriptor writeback.
  */
 
-/* NOTE:  DMS+SMS is system-specific. We should get this information
- * from the platform code somehow.
- */
-#define DWC_DEFAULT_CTLLO	(DWC_CTLL_DST_MSIZE(0)		\
-				| DWC_CTLL_SRC_MSIZE(0)		\
-				| DWC_CTLL_DMS(0)		\
-				| DWC_CTLL_SMS(1)		\
-				| DWC_CTLL_LLP_D_EN		\
-				| DWC_CTLL_LLP_S_EN)
+#define DWC_DEFAULT_CTLLO(private) ({				\
+		struct dw_dma_slave *__slave = (private);	\
+		int dms = __slave ? __slave->dst_master : 0;	\
+		int sms = __slave ? __slave->src_master : 1;	\
+								\
+		(DWC_CTLL_DST_MSIZE(0)				\
+		 | DWC_CTLL_SRC_MSIZE(0)			\
+		 | DWC_CTLL_LLP_D_EN				\
+		 | DWC_CTLL_LLP_S_EN				\
+		 | DWC_CTLL_DMS(dms)				\
+		 | DWC_CTLL_SMS(sms));				\
+	})
 
 /*
  * This is configuration-dependent and usually a funny size like 4095.
@@ -591,7 +594,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 	else
 		src_width = dst_width = 0;
 
-	ctllo = DWC_DEFAULT_CTLLO
+	ctllo = DWC_DEFAULT_CTLLO(chan->private)
 			| DWC_CTLL_DST_WIDTH(dst_width)
 			| DWC_CTLL_SRC_WIDTH(src_width)
 			| DWC_CTLL_DST_INC
@@ -672,7 +675,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 
 	switch (direction) {
 	case DMA_TO_DEVICE:
-		ctllo = (DWC_DEFAULT_CTLLO
+		ctllo = (DWC_DEFAULT_CTLLO(chan->private)
 				| DWC_CTLL_DST_WIDTH(reg_width)
 				| DWC_CTLL_DST_FIX
 				| DWC_CTLL_SRC_INC
@@ -717,7 +720,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 		}
 		break;
 	case DMA_FROM_DEVICE:
-		ctllo = (DWC_DEFAULT_CTLLO
+		ctllo = (DWC_DEFAULT_CTLLO(chan->private)
 				| DWC_CTLL_SRC_WIDTH(reg_width)
 				| DWC_CTLL_DST_INC
 				| DWC_CTLL_SRC_FIX
@@ -1129,7 +1132,7 @@ struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
 		case DMA_TO_DEVICE:
 			desc->lli.dar = dws->tx_reg;
 			desc->lli.sar = buf_addr + (period_len * i);
-			desc->lli.ctllo = (DWC_DEFAULT_CTLLO
+			desc->lli.ctllo = (DWC_DEFAULT_CTLLO(chan->private)
 					| DWC_CTLL_DST_WIDTH(reg_width)
 					| DWC_CTLL_SRC_WIDTH(reg_width)
 					| DWC_CTLL_DST_FIX
@@ -1140,7 +1143,7 @@ struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
 		case DMA_FROM_DEVICE:
 			desc->lli.dar = buf_addr + (period_len * i);
 			desc->lli.sar = dws->rx_reg;
-			desc->lli.ctllo = (DWC_DEFAULT_CTLLO
+			desc->lli.ctllo = (DWC_DEFAULT_CTLLO(chan->private)
 					| DWC_CTLL_SRC_WIDTH(reg_width)
 					| DWC_CTLL_DST_WIDTH(reg_width)
 					| DWC_CTLL_DST_INC

include/linux/dw_dmac.h

@@ -52,6 +52,8 @@ struct dw_dma_slave {
 	enum dw_dma_slave_width	reg_width;
 	u32			cfg_hi;
 	u32			cfg_lo;
+	int			src_master;
+	int			dst_master;
 };
 
 /* Platform-configurable bits in CFG_HI */