[PATCH 2/4] dmaengine/dw_dmac: allow src/dst masters to be configured at runtime

[Jamie Iles]

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.

Cc: Haavard Skinnemoen <haavard.skinnemoen@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Jamie Iles <jamie.iles@xxxxxxxxxxxx>
---
 drivers/dma/dw_dmac.c   |   31 +++++++++++++++++--------------
 include/linux/dw_dmac.h |    2 ++
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 08c51d4..64024f1 100644
--- a/drivers/dma/dw_dmac.c
+++ b/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
diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h
index c8aad71..8014eb8 100644
--- a/include/linux/dw_dmac.h
+++ b/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 */
-- 
1.7.2.3

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