dmaengine: at_xdmac: handle numf > 1

Handle 'numf > 1' case for interleaved mode.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/at_xdmac.c

@@ -929,13 +929,19 @@ at_xdmac_prep_interleaved(struct dma_chan *chan,
 {
 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
 	struct at_xdmac_desc	*prev = NULL, *first = NULL;
-	struct data_chunk	*chunk, *prev_chunk = NULL;
 	dma_addr_t		dst_addr, src_addr;
-	size_t			dst_skip, src_skip, len = 0;
-	size_t			prev_dst_icg = 0, prev_src_icg = 0;
+	size_t			src_skip = 0, dst_skip = 0, len = 0;
+	struct data_chunk	*chunk;
 	int			i;
 
-	if (!xt || (xt->numf != 1) || (xt->dir != DMA_MEM_TO_MEM))
+	if (!xt || !xt->numf || (xt->dir != DMA_MEM_TO_MEM))
+		return NULL;
+
+	/*
+	 * TODO: Handle the case where we have to repeat a chain of
+	 * descriptors...
+	 */
+	if ((xt->numf > 1) && (xt->frame_size > 1))
 		return NULL;
 
 	dev_dbg(chan2dev(chan), "%s: src=0x%08x, dest=0x%08x, numf=%d, frame_size=%d, flags=0x%lx\n",
@@ -945,9 +951,17 @@ at_xdmac_prep_interleaved(struct dma_chan *chan,
 	src_addr = xt->src_start;
 	dst_addr = xt->dst_start;
 
+	if (xt->numf > 1) {
+		first = at_xdmac_interleaved_queue_desc(chan, atchan,
+							NULL,
+							src_addr, dst_addr,
+							xt, xt->sgl);
+		for (i = 0; i < xt->numf; i++)
+			at_xdmac_increment_block_count(chan, first);
+	} else {
 		for (i = 0; i < xt->frame_size; i++) {
+			size_t src_icg = 0, dst_icg = 0;
 			struct at_xdmac_desc *desc;
-		size_t src_icg, dst_icg;
 
 			chunk = xt->sgl + i;
 
@@ -961,22 +975,6 @@ at_xdmac_prep_interleaved(struct dma_chan *chan,
 				"%s: chunk size=%d, src icg=%d, dst icg=%d\n",
 				__func__, chunk->size, src_icg, dst_icg);
 
-		/*
-		 * Handle the case where we just have the same
-		 * transfer to setup, we can just increase the
-		 * block number and reuse the same descriptor.
-		 */
-		if (prev_chunk && prev &&
-		    (prev_chunk->size == chunk->size) &&
-		    (prev_src_icg == src_icg) &&
-		    (prev_dst_icg == dst_icg)) {
-			dev_dbg(chan2dev(chan),
-				"%s: same configuration that the previous chunk, merging the descriptors...\n",
-				__func__);
-			at_xdmac_increment_block_count(chan, prev);
-			continue;
-		}
-
 			desc = at_xdmac_interleaved_queue_desc(chan, atchan,
 							       prev,
 							       src_addr, dst_addr,
@@ -1001,11 +999,9 @@ at_xdmac_prep_interleaved(struct dma_chan *chan,
 				dst_addr += dst_skip;
 
 			len += chunk->size;
-		prev_chunk = chunk;
-		prev_dst_icg = dst_icg;
-		prev_src_icg = src_icg;
 			prev = desc;
 		}
+	}
 
 	first->tx_dma_desc.cookie = -EBUSY;
 	first->tx_dma_desc.flags = flags;