at_hdmac: implement a private tx_list

Drop at_hdmac's use of tx_list from struct dma_async_tx_descriptor in
preparation for removal of this field.

Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/at_hdmac.c

@@ -87,6 +87,7 @@ static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan,
 	desc = dma_pool_alloc(atdma->dma_desc_pool, gfp_flags, &phys);
 	if (desc) {
 		memset(desc, 0, sizeof(struct at_desc));
+		INIT_LIST_HEAD(&desc->tx_list);
 		dma_async_tx_descriptor_init(&desc->txd, chan);
 		/* txd.flags will be overwritten in prep functions */
 		desc->txd.flags = DMA_CTRL_ACK;
@@ -150,11 +151,11 @@ static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
 		struct at_desc *child;
 
 		spin_lock_bh(&atchan->lock);
-		list_for_each_entry(child, &desc->txd.tx_list, desc_node)
+		list_for_each_entry(child, &desc->tx_list, desc_node)
 			dev_vdbg(chan2dev(&atchan->chan_common),
 					"moving child desc %p to freelist\n",
 					child);
-		list_splice_init(&desc->txd.tx_list, &atchan->free_list);
+		list_splice_init(&desc->tx_list, &atchan->free_list);
 		dev_vdbg(chan2dev(&atchan->chan_common),
 			 "moving desc %p to freelist\n", desc);
 		list_add(&desc->desc_node, &atchan->free_list);
@@ -247,7 +248,7 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
 	param = txd->callback_param;
 
 	/* move children to free_list */
-	list_splice_init(&txd->tx_list, &atchan->free_list);
+	list_splice_init(&desc->tx_list, &atchan->free_list);
 	/* move myself to free_list */
 	list_move(&desc->desc_node, &atchan->free_list);
 
@@ -334,7 +335,7 @@ static void atc_cleanup_descriptors(struct at_dma_chan *atchan)
 			/* This one is currently in progress */
 			return;
 
-		list_for_each_entry(child, &desc->txd.tx_list, desc_node)
+		list_for_each_entry(child, &desc->tx_list, desc_node)
 			if (!(child->lli.ctrla & ATC_DONE))
 				/* Currently in progress */
 				return;
@@ -407,7 +408,7 @@ static void atc_handle_error(struct at_dma_chan *atchan)
 	dev_crit(chan2dev(&atchan->chan_common),
 			"  cookie: %d\n", bad_desc->txd.cookie);
 	atc_dump_lli(atchan, &bad_desc->lli);
-	list_for_each_entry(child, &bad_desc->txd.tx_list, desc_node)
+	list_for_each_entry(child, &bad_desc->tx_list, desc_node)
 		atc_dump_lli(atchan, &child->lli);
 
 	/* Pretend the descriptor completed successfully */
@@ -587,7 +588,7 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 			prev->lli.dscr = desc->txd.phys;
 			/* insert the link descriptor to the LD ring */
 			list_add_tail(&desc->desc_node,
-					&first->txd.tx_list);
+					&first->tx_list);
 		}
 		prev = desc;
 	}
@@ -687,7 +688,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 				prev->lli.dscr = desc->txd.phys;
 				/* insert the link descriptor to the LD ring */
 				list_add_tail(&desc->desc_node,
-						&first->txd.tx_list);
+						&first->tx_list);
 			}
 			prev = desc;
 			total_len += len;
@@ -729,7 +730,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 				prev->lli.dscr = desc->txd.phys;
 				/* insert the link descriptor to the LD ring */
 				list_add_tail(&desc->desc_node,
-						&first->txd.tx_list);
+						&first->tx_list);
 			}
 			prev = desc;
 			total_len += len;

drivers/dma/at_hdmac_regs.h

@@ -165,6 +165,7 @@ struct at_desc {
 	struct at_lli			lli;
 
 	/* THEN values for driver housekeeping */
+	struct list_head		tx_list;
 	struct dma_async_tx_descriptor	txd;
 	struct list_head		desc_node;
 	size_t				len;