Merge branch 'topic/qcom' into for-linus

drivers/dma/qcom/bam_dma.c

@@ -46,6 +46,7 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_dma.h>
+#include <linux/circ_buf.h>
 #include <linux/clk.h>
 #include <linux/dmaengine.h>
 #include <linux/pm_runtime.h>
@@ -78,6 +79,8 @@ struct bam_async_desc {
 
 	struct bam_desc_hw *curr_desc;
 
+	/* list node for the desc in the bam_chan list of descriptors */
+	struct list_head desc_node;
 	enum dma_transfer_direction dir;
 	size_t length;
 	struct bam_desc_hw desc[0];
@@ -347,6 +350,8 @@ static const struct reg_offset_data bam_v1_7_reg_info[] = {
 #define BAM_DESC_FIFO_SIZE	SZ_32K
 #define MAX_DESCRIPTORS (BAM_DESC_FIFO_SIZE / sizeof(struct bam_desc_hw) - 1)
 #define BAM_FIFO_SIZE	(SZ_32K - 8)
+#define IS_BUSY(chan)	(CIRC_SPACE(bchan->tail, bchan->head,\
+			 MAX_DESCRIPTORS + 1) == 0)
 
 struct bam_chan {
 	struct virt_dma_chan vc;
@@ -356,8 +361,6 @@ struct bam_chan {
 	/* configuration from device tree */
 	u32 id;
 
-	struct bam_async_desc *curr_txd;	/* current running dma */
-
 	/* runtime configuration */
 	struct dma_slave_config slave;
 
@@ -372,6 +375,8 @@ struct bam_chan {
 	unsigned int initialized;	/* is the channel hw initialized? */
 	unsigned int paused;		/* is the channel paused? */
 	unsigned int reconfigure;	/* new slave config? */
+	/* list of descriptors currently processed */
+	struct list_head desc_list;
 
 	struct list_head node;
 };
@@ -539,7 +544,7 @@ static void bam_free_chan(struct dma_chan *chan)
 
 	vchan_free_chan_resources(to_virt_chan(chan));
 
-	if (bchan->curr_txd) {
+	if (!list_empty(&bchan->desc_list)) {
 		dev_err(bchan->bdev->dev, "Cannot free busy channel\n");
 		goto err;
 	}
@@ -632,8 +637,6 @@ static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
 
 	if (flags & DMA_PREP_INTERRUPT)
 		async_desc->flags |= DESC_FLAG_EOT;
-	else
-		async_desc->flags |= DESC_FLAG_INT;
 
 	async_desc->num_desc = num_alloc;
 	async_desc->curr_desc = async_desc->desc;
@@ -684,14 +687,16 @@ static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
 static int bam_dma_terminate_all(struct dma_chan *chan)
 {
 	struct bam_chan *bchan = to_bam_chan(chan);
+	struct bam_async_desc *async_desc, *tmp;
 	unsigned long flag;
 	LIST_HEAD(head);
 
 	/* remove all transactions, including active transaction */
 	spin_lock_irqsave(&bchan->vc.lock, flag);
-	if (bchan->curr_txd) {
-		list_add(&bchan->curr_txd->vd.node, &bchan->vc.desc_issued);
-		bchan->curr_txd = NULL;
+	list_for_each_entry_safe(async_desc, tmp,
+				 &bchan->desc_list, desc_node) {
+		list_add(&async_desc->vd.node, &bchan->vc.desc_issued);
+		list_del(&async_desc->desc_node);
 	}
 
 	vchan_get_all_descriptors(&bchan->vc, &head);
@@ -763,9 +768,9 @@ static int bam_resume(struct dma_chan *chan)
  */
 static u32 process_channel_irqs(struct bam_device *bdev)
 {
-	u32 i, srcs, pipe_stts;
+	u32 i, srcs, pipe_stts, offset, avail;
 	unsigned long flags;
-	struct bam_async_desc *async_desc;
+	struct bam_async_desc *async_desc, *tmp;
 
 	srcs = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_EE));
 
@@ -785,28 +790,41 @@ static u32 process_channel_irqs(struct bam_device *bdev)
 		writel_relaxed(pipe_stts, bam_addr(bdev, i, BAM_P_IRQ_CLR));
 
 		spin_lock_irqsave(&bchan->vc.lock, flags);
-		async_desc = bchan->curr_txd;
 
-		if (async_desc) {
-			async_desc->num_desc -= async_desc->xfer_len;
-			async_desc->curr_desc += async_desc->xfer_len;
-			bchan->curr_txd = NULL;
+		offset = readl_relaxed(bam_addr(bdev, i, BAM_P_SW_OFSTS)) &
+				       P_SW_OFSTS_MASK;
+		offset /= sizeof(struct bam_desc_hw);
+
+		/* Number of bytes available to read */
+		avail = CIRC_CNT(offset, bchan->head, MAX_DESCRIPTORS + 1);
+
+		list_for_each_entry_safe(async_desc, tmp,
+					 &bchan->desc_list, desc_node) {
+			/* Not enough data to read */
+			if (avail < async_desc->xfer_len)
+				break;
 
 			/* manage FIFO */
 			bchan->head += async_desc->xfer_len;
 			bchan->head %= MAX_DESCRIPTORS;
 
+			async_desc->num_desc -= async_desc->xfer_len;
+			async_desc->curr_desc += async_desc->xfer_len;
+			avail -= async_desc->xfer_len;
+
 			/*
 			 * if complete, process cookie. Otherwise
 			 * push back to front of desc_issued so that
 			 * it gets restarted by the tasklet
 			 */
-			if (!async_desc->num_desc)
+			if (!async_desc->num_desc) {
 				vchan_cookie_complete(&async_desc->vd);
-			else
+			} else {
 				list_add(&async_desc->vd.node,
 					 &bchan->vc.desc_issued);
 			}
+			list_del(&async_desc->desc_node);
+		}
 
 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
 	}
@@ -867,6 +885,7 @@ static enum dma_status bam_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
 		struct dma_tx_state *txstate)
 {
 	struct bam_chan *bchan = to_bam_chan(chan);
+	struct bam_async_desc *async_desc;
 	struct virt_dma_desc *vd;
 	int ret;
 	size_t residue = 0;
@@ -882,11 +901,17 @@ static enum dma_status bam_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
 
 	spin_lock_irqsave(&bchan->vc.lock, flags);
 	vd = vchan_find_desc(&bchan->vc, cookie);
-	if (vd)
+	if (vd) {
 		residue = container_of(vd, struct bam_async_desc, vd)->length;
-	else if (bchan->curr_txd && bchan->curr_txd->vd.tx.cookie == cookie)
-		for (i = 0; i < bchan->curr_txd->num_desc; i++)
-			residue += bchan->curr_txd->curr_desc[i].size;
+	} else {
+		list_for_each_entry(async_desc, &bchan->desc_list, desc_node) {
+			if (async_desc->vd.tx.cookie != cookie)
+				continue;
+
+			for (i = 0; i < async_desc->num_desc; i++)
+				residue += async_desc->curr_desc[i].size;
+		}
+	}
 
 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
 
@@ -927,26 +952,28 @@ static void bam_start_dma(struct bam_chan *bchan)
 {
 	struct virt_dma_desc *vd = vchan_next_desc(&bchan->vc);
 	struct bam_device *bdev = bchan->bdev;
-	struct bam_async_desc *async_desc;
+	struct bam_async_desc *async_desc = NULL;
 	struct bam_desc_hw *desc;
 	struct bam_desc_hw *fifo = PTR_ALIGN(bchan->fifo_virt,
 					sizeof(struct bam_desc_hw));
 	int ret;
+	unsigned int avail;
+	struct dmaengine_desc_callback cb;
 
 	lockdep_assert_held(&bchan->vc.lock);
 
 	if (!vd)
 		return;
 
-	list_del(&vd->node);
-
-	async_desc = container_of(vd, struct bam_async_desc, vd);
-	bchan->curr_txd = async_desc;
-
 	ret = pm_runtime_get_sync(bdev->dev);
 	if (ret < 0)
 		return;
 
+	while (vd && !IS_BUSY(bchan)) {
+		list_del(&vd->node);
+
+		async_desc = container_of(vd, struct bam_async_desc, vd);
+
 		/* on first use, initialize the channel hardware */
 		if (!bchan->initialized)
 			bam_chan_init_hw(bchan, async_desc->dir);
@@ -955,10 +982,12 @@ static void bam_start_dma(struct bam_chan *bchan)
 		if (bchan->reconfigure)
 			bam_apply_new_config(bchan, async_desc->dir);
 
-	desc = bchan->curr_txd->curr_desc;
+		desc = async_desc->curr_desc;
+		avail = CIRC_SPACE(bchan->tail, bchan->head,
+				   MAX_DESCRIPTORS + 1);
 
-	if (async_desc->num_desc > MAX_DESCRIPTORS)
-		async_desc->xfer_len = MAX_DESCRIPTORS;
+		if (async_desc->num_desc > avail)
+			async_desc->xfer_len = avail;
 		else
 			async_desc->xfer_len = async_desc->num_desc;
 
@@ -966,7 +995,22 @@ static void bam_start_dma(struct bam_chan *bchan)
 		if (async_desc->num_desc == async_desc->xfer_len)
 			desc[async_desc->xfer_len - 1].flags |=
 						cpu_to_le16(async_desc->flags);
-	else
+
+		vd = vchan_next_desc(&bchan->vc);
+
+		dmaengine_desc_get_callback(&async_desc->vd.tx, &cb);
+
+		/*
+		 * An interrupt is generated at this desc, if
+		 *  - FIFO is FULL.
+		 *  - No more descriptors to add.
+		 *  - If a callback completion was requested for this DESC,
+		 *     In this case, BAM will deliver the completion callback
+		 *     for this desc and continue processing the next desc.
+		 */
+		if (((avail <= async_desc->xfer_len) || !vd ||
+		     dmaengine_desc_callback_valid(&cb)) &&
+		    !(async_desc->flags & DESC_FLAG_EOT))
 			desc[async_desc->xfer_len - 1].flags |=
 				cpu_to_le16(DESC_FLAG_INT);
 
@@ -975,15 +1019,19 @@ static void bam_start_dma(struct bam_chan *bchan)
 
 			memcpy(&fifo[bchan->tail], desc,
 			       partial * sizeof(struct bam_desc_hw));
-		memcpy(fifo, &desc[partial], (async_desc->xfer_len - partial) *
+			memcpy(fifo, &desc[partial],
+			       (async_desc->xfer_len - partial) *
 				sizeof(struct bam_desc_hw));
 		} else {
 			memcpy(&fifo[bchan->tail], desc,
-			async_desc->xfer_len * sizeof(struct bam_desc_hw));
+			       async_desc->xfer_len *
+			       sizeof(struct bam_desc_hw));
 		}
 
 		bchan->tail += async_desc->xfer_len;
 		bchan->tail %= MAX_DESCRIPTORS;
+		list_add_tail(&async_desc->desc_node, &bchan->desc_list);
+	}
 
 	/* ensure descriptor writes and dma start not reordered */
 	wmb();
@@ -1012,7 +1060,7 @@ static void dma_tasklet(unsigned long data)
 		bchan = &bdev->channels[i];
 		spin_lock_irqsave(&bchan->vc.lock, flags);
 
-		if (!list_empty(&bchan->vc.desc_issued) && !bchan->curr_txd)
+		if (!list_empty(&bchan->vc.desc_issued) && !IS_BUSY(bchan))
 			bam_start_dma(bchan);
 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
 	}
@@ -1033,7 +1081,7 @@ static void bam_issue_pending(struct dma_chan *chan)
 	spin_lock_irqsave(&bchan->vc.lock, flags);
 
 	/* if work pending and idle, start a transaction */
-	if (vchan_issue_pending(&bchan->vc) && !bchan->curr_txd)
+	if (vchan_issue_pending(&bchan->vc) && !IS_BUSY(bchan))
 		bam_start_dma(bchan);
 
 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
@@ -1133,6 +1181,7 @@ static void bam_channel_init(struct bam_device *bdev, struct bam_chan *bchan,
 
 	vchan_init(&bchan->vc, &bdev->common);
 	bchan->vc.desc_free = bam_dma_free_desc;
+	INIT_LIST_HEAD(&bchan->desc_list);
 }
 
 static const struct of_device_id bam_of_match[] = {