1 files changed, 60 insertions, 93 deletions

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 5a50423b7378..858bd64f1313 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -256,6 +256,8 @@ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
 		       ATC_SPIP_BOUNDARY(first->boundary));
 	channel_writel(atchan, DPIP, ATC_DPIP_HOLE(first->dst_hole) |
 		       ATC_DPIP_BOUNDARY(first->boundary));
+	/* Don't allow CPU to reorder channel enable. */
+	wmb();
 	dma_writel(atdma, CHER, atchan->mask);
 
 	vdbg_dump_regs(atchan);
@@ -316,7 +318,8 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
 	struct at_desc *desc_first = atc_first_active(atchan);
 	struct at_desc *desc;
 	int ret;
-	u32 ctrla, dscr, trials;
+	u32 ctrla, dscr;
+	unsigned int i;
 
 	/*
 	 * If the cookie doesn't match to the currently running transfer then
@@ -386,7 +389,7 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
 		dscr = channel_readl(atchan, DSCR);
 		rmb(); /* ensure DSCR is read before CTRLA */
 		ctrla = channel_readl(atchan, CTRLA);
-		for (trials = 0; trials < ATC_MAX_DSCR_TRIALS; ++trials) {
+		for (i = 0; i < ATC_MAX_DSCR_TRIALS; ++i) {
 			u32 new_dscr;
 
 			rmb(); /* ensure DSCR is read after CTRLA */
@@ -412,7 +415,7 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
 			rmb(); /* ensure DSCR is read before CTRLA */
 			ctrla = channel_readl(atchan, CTRLA);
 		}
-		if (unlikely(trials >= ATC_MAX_DSCR_TRIALS))
+		if (unlikely(i == ATC_MAX_DSCR_TRIALS))
 			return -ETIMEDOUT;
 
 		/* for the first descriptor we can be more accurate */
@@ -462,18 +465,6 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
 	if (!atc_chan_is_cyclic(atchan))
 		dma_cookie_complete(txd);
 
-	/* If the transfer was a memset, free our temporary buffer */
-	if (desc->memset_buffer) {
-		dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
-			      desc->memset_paddr);
-		desc->memset_buffer = false;
-	}
-
-	/* move children to free_list */
-	list_splice_init(&desc->tx_list, &atchan->free_list);
-	/* move myself to free_list */
-	list_move(&desc->desc_node, &atchan->free_list);
-
 	spin_unlock_irqrestore(&atchan->lock, flags);
 
 	dma_descriptor_unmap(txd);
@@ -483,42 +474,20 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
 		dmaengine_desc_get_callback_invoke(txd, NULL);
 
 	dma_run_dependencies(txd);
-}
-
-/**
- * atc_complete_all - finish work for all transactions
- * @atchan: channel to complete transactions for
- *
- * Eventually submit queued descriptors if any
- *
- * Assume channel is idle while calling this function
- * Called with atchan->lock held and bh disabled
- */
-static void atc_complete_all(struct at_dma_chan *atchan)
-{
-	struct at_desc *desc, *_desc;
-	LIST_HEAD(list);
-	unsigned long flags;
-
-	dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n");
 
 	spin_lock_irqsave(&atchan->lock, flags);
-
-	/*
-	 * Submit queued descriptors ASAP, i.e. before we go through
-	 * the completed ones.
-	 */
-	if (!list_empty(&atchan->queue))
-		atc_dostart(atchan, atc_first_queued(atchan));
-	/* empty active_list now it is completed */
-	list_splice_init(&atchan->active_list, &list);
-	/* empty queue list by moving descriptors (if any) to active_list */
-	list_splice_init(&atchan->queue, &atchan->active_list);
-
+	/* move children to free_list */
+	list_splice_init(&desc->tx_list, &atchan->free_list);
+	/* add myself to free_list */
+	list_add(&desc->desc_node, &atchan->free_list);
 	spin_unlock_irqrestore(&atchan->lock, flags);
 
-	list_for_each_entry_safe(desc, _desc, &list, desc_node)
-		atc_chain_complete(atchan, desc);
+	/* If the transfer was a memset, free our temporary buffer */
+	if (desc->memset_buffer) {
+		dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
+			      desc->memset_paddr);
+		desc->memset_buffer = false;
+	}
 }
 
 /**
@@ -527,26 +496,28 @@ static void atc_complete_all(struct at_dma_chan *atchan)
  */
 static void atc_advance_work(struct at_dma_chan *atchan)
 {
+	struct at_desc *desc;
 	unsigned long flags;
-	int ret;
 
 	dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
 
 	spin_lock_irqsave(&atchan->lock, flags);
-	ret = atc_chan_is_enabled(atchan);
-	spin_unlock_irqrestore(&atchan->lock, flags);
-	if (ret)
-		return;
-
-	if (list_empty(&atchan->active_list) ||
-	    list_is_singular(&atchan->active_list))
-		return atc_complete_all(atchan);
+	if (atc_chan_is_enabled(atchan) || list_empty(&atchan->active_list))
+		return spin_unlock_irqrestore(&atchan->lock, flags);
 
-	atc_chain_complete(atchan, atc_first_active(atchan));
+	desc = atc_first_active(atchan);
+	/* Remove the transfer node from the active list. */
+	list_del_init(&desc->desc_node);
+	spin_unlock_irqrestore(&atchan->lock, flags);
+	atc_chain_complete(atchan, desc);
 
 	/* advance work */
 	spin_lock_irqsave(&atchan->lock, flags);
-	atc_dostart(atchan, atc_first_active(atchan));
+	if (!list_empty(&atchan->active_list)) {
+		desc = atc_first_queued(atchan);
+		list_move_tail(&desc->desc_node, &atchan->active_list);
+		atc_dostart(atchan, desc);
+	}
 	spin_unlock_irqrestore(&atchan->lock, flags);
 }
 
@@ -558,6 +529,7 @@ static void atc_advance_work(struct at_dma_chan *atchan)
 static void atc_handle_error(struct at_dma_chan *atchan)
 {
 	struct at_desc *bad_desc;
+	struct at_desc *desc;
 	struct at_desc *child;
 	unsigned long flags;
 
@@ -570,13 +542,12 @@ static void atc_handle_error(struct at_dma_chan *atchan)
 	bad_desc = atc_first_active(atchan);
 	list_del_init(&bad_desc->desc_node);
 
-	/* As we are stopped, take advantage to push queued descriptors
-	 * in active_list */
-	list_splice_init(&atchan->queue, atchan->active_list.prev);
-
 	/* Try to restart the controller */
-	if (!list_empty(&atchan->active_list))
-		atc_dostart(atchan, atc_first_active(atchan));
+	if (!list_empty(&atchan->active_list)) {
+		desc = atc_first_queued(atchan);
+		list_move_tail(&desc->desc_node, &atchan->active_list);
+		atc_dostart(atchan, desc);
+	}
 
 	/*
 	 * KERN_CRITICAL may seem harsh, but since this only happens
@@ -691,19 +662,11 @@ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
 	spin_lock_irqsave(&atchan->lock, flags);
 	cookie = dma_cookie_assign(tx);
 
-	if (list_empty(&atchan->active_list)) {
-		dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n",
-				desc->txd.cookie);
-		atc_dostart(atchan, desc);
-		list_add_tail(&desc->desc_node, &atchan->active_list);
-	} else {
-		dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
-				desc->txd.cookie);
-		list_add_tail(&desc->desc_node, &atchan->queue);
-	}
-
+	list_add_tail(&desc->desc_node, &atchan->queue);
 	spin_unlock_irqrestore(&atchan->lock, flags);
 
+	dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
+		 desc->txd.cookie);
 	return cookie;
 }
 
@@ -1445,11 +1408,8 @@ static int atc_terminate_all(struct dma_chan *chan)
 	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
 	struct at_dma		*atdma = to_at_dma(chan->device);
 	int			chan_id = atchan->chan_common.chan_id;
-	struct at_desc		*desc, *_desc;
 	unsigned long		flags;
 
-	LIST_HEAD(list);
-
 	dev_vdbg(chan2dev(chan), "%s\n", __func__);
 
 	/*
@@ -1468,19 +1428,15 @@ static int atc_terminate_all(struct dma_chan *chan)
 		cpu_relax();
 
 	/* active_list entries will end up before queued entries */
-	list_splice_init(&atchan->queue, &list);
-	list_splice_init(&atchan->active_list, &list);
-
-	spin_unlock_irqrestore(&atchan->lock, flags);
-
-	/* Flush all pending and queued descriptors */
-	list_for_each_entry_safe(desc, _desc, &list, desc_node)
-		atc_chain_complete(atchan, desc);
+	list_splice_tail_init(&atchan->queue, &atchan->free_list);
+	list_splice_tail_init(&atchan->active_list, &atchan->free_list);
 
 	clear_bit(ATC_IS_PAUSED, &atchan->status);
 	/* if channel dedicated to cyclic operations, free it */
 	clear_bit(ATC_IS_CYCLIC, &atchan->status);
 
+	spin_unlock_irqrestore(&atchan->lock, flags);
+
 	return 0;
 }
 
@@ -1535,20 +1491,26 @@ atc_tx_status(struct dma_chan *chan,
 }
 
 /**
- * atc_issue_pending - try to finish work
+ * atc_issue_pending - takes the first transaction descriptor in the pending
+ * queue and starts the transfer.
  * @chan: target DMA channel
  */
 static void atc_issue_pending(struct dma_chan *chan)
 {
-	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
+	struct at_dma_chan *atchan = to_at_dma_chan(chan);
+	struct at_desc *desc;
+	unsigned long flags;
 
 	dev_vdbg(chan2dev(chan), "issue_pending\n");
 
-	/* Not needed for cyclic transfers */
-	if (atc_chan_is_cyclic(atchan))
-		return;
+	spin_lock_irqsave(&atchan->lock, flags);
+	if (atc_chan_is_enabled(atchan) || list_empty(&atchan->queue))
+		return spin_unlock_irqrestore(&atchan->lock, flags);
 
-	atc_advance_work(atchan);
+	desc = atc_first_queued(atchan);
+	list_move_tail(&desc->desc_node, &atchan->active_list);
+	atc_dostart(atchan, desc);
+	spin_unlock_irqrestore(&atchan->lock, flags);
 }
 
 /**
@@ -1966,7 +1928,11 @@ static int __init at_dma_probe(struct platform_device *pdev)
 	  dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)  ? "slave " : "",
 	  plat_dat->nr_channels);
 
-	dma_async_device_register(&atdma->dma_common);
+	err = dma_async_device_register(&atdma->dma_common);
+	if (err) {
+		dev_err(&pdev->dev, "Unable to register: %d.\n", err);
+		goto err_dma_async_device_register;
+	}
 
 	/*
 	 * Do not return an error if the dmac node is not present in order to
@@ -1986,6 +1952,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
 
 err_of_dma_controller_register:
 	dma_async_device_unregister(&atdma->dma_common);
+err_dma_async_device_register:
 	dma_pool_destroy(atdma->memset_pool);
 err_memset_pool_create:
 	dma_pool_destroy(atdma->dma_desc_pool);