1 files changed, 151 insertions, 8 deletions

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 183ec85..592f3be 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -60,6 +60,7 @@
 struct edma_desc {
 	struct virt_dma_desc		vdesc;
 	struct list_head		node;
+	int				cyclic;
 	int				absync;
 	int				pset_nr;
 	int				processed;
@@ -173,8 +174,13 @@ static void edma_execute(struct edma_chan *echan)
 	 * then setup a link to the dummy slot, this results in all future
 	 * events being absorbed and that's OK because we're done
 	 */
-	if (edesc->processed == edesc->pset_nr)
-		edma_link(echan->slot[nslots-1], echan->ecc->dummy_slot);
+	if (edesc->processed == edesc->pset_nr) {
+		if (edesc->cyclic)
+			edma_link(echan->slot[nslots-1], echan->slot[1]);
+		else
+			edma_link(echan->slot[nslots-1],
+				  echan->ecc->dummy_slot);
+	}
 
 	edma_resume(echan->ch_num);
 
@@ -459,6 +465,138 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 	return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
 }
 
+static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
+	struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+	size_t period_len, enum dma_transfer_direction direction,
+	unsigned long tx_flags, void *context)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	struct edma_desc *edesc;
+	dma_addr_t src_addr, dst_addr;
+	enum dma_slave_buswidth dev_width;
+	u32 burst;
+	int i, ret, nslots;
+
+	if (unlikely(!echan || !buf_len || !period_len))
+		return NULL;
+
+	if (direction == DMA_DEV_TO_MEM) {
+		src_addr = echan->cfg.src_addr;
+		dst_addr = buf_addr;
+		dev_width = echan->cfg.src_addr_width;
+		burst = echan->cfg.src_maxburst;
+	} else if (direction == DMA_MEM_TO_DEV) {
+		src_addr = buf_addr;
+		dst_addr = echan->cfg.dst_addr;
+		dev_width = echan->cfg.dst_addr_width;
+		burst = echan->cfg.dst_maxburst;
+	} else {
+		dev_err(dev, "%s: bad direction?\n", __func__);
+		return NULL;
+	}
+
+	if (dev_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
+		dev_err(dev, "Undefined slave buswidth\n");
+		return NULL;
+	}
+
+	if (unlikely(buf_len % period_len)) {
+		dev_err(dev, "Period should be multiple of Buffer length\n");
+		return NULL;
+	}
+
+	nslots = (buf_len / period_len) + 1;
+
+	/*
+	 * Cyclic DMA users such as audio cannot tolerate delays introduced
+	 * by cases where the number of periods is more than the maximum
+	 * number of SGs the EDMA driver can handle at a time. For DMA types
+	 * such as Slave SGs, such delays are tolerable and synchronized,
+	 * but the synchronization is difficult to achieve with Cyclic and
+	 * cannot be guaranteed, so we error out early.
+	 */
+	if (nslots > MAX_NR_SG)
+		return NULL;
+
+	edesc = kzalloc(sizeof(*edesc) + nslots *
+		sizeof(edesc->pset[0]), GFP_ATOMIC);
+	if (!edesc) {
+		dev_dbg(dev, "Failed to allocate a descriptor\n");
+		return NULL;
+	}
+
+	edesc->cyclic = 1;
+	edesc->pset_nr = nslots;
+
+	dev_dbg(dev, "%s: nslots=%d\n", __func__, nslots);
+	dev_dbg(dev, "%s: period_len=%d\n", __func__, period_len);
+	dev_dbg(dev, "%s: buf_len=%d\n", __func__, buf_len);
+
+	for (i = 0; i < nslots; i++) {
+		/* Allocate a PaRAM slot, if needed */
+		if (echan->slot[i] < 0) {
+			echan->slot[i] =
+				edma_alloc_slot(EDMA_CTLR(echan->ch_num),
+						EDMA_SLOT_ANY);
+			if (echan->slot[i] < 0) {
+				dev_err(dev, "Failed to allocate slot\n");
+				return NULL;
+			}
+		}
+
+		if (i == nslots - 1) {
+			memcpy(&edesc->pset[i], &edesc->pset[0],
+			       sizeof(edesc->pset[0]));
+			break;
+		}
+
+		ret = edma_config_pset(chan, &edesc->pset[i], src_addr,
+				       dst_addr, burst, dev_width, period_len,
+				       direction);
+		if (ret < 0)
+			return NULL;
+
+		if (direction == DMA_DEV_TO_MEM)
+			dst_addr += period_len;
+		else
+			src_addr += period_len;
+
+		dev_dbg(dev, "%s: Configure period %d of buf:\n", __func__, i);
+		dev_dbg(dev,
+			"\n pset[%d]:\n"
+			"  chnum\t%d\n"
+			"  slot\t%d\n"
+			"  opt\t%08x\n"
+			"  src\t%08x\n"
+			"  dst\t%08x\n"
+			"  abcnt\t%08x\n"
+			"  ccnt\t%08x\n"
+			"  bidx\t%08x\n"
+			"  cidx\t%08x\n"
+			"  lkrld\t%08x\n",
+			i, echan->ch_num, echan->slot[i],
+			edesc->pset[i].opt,
+			edesc->pset[i].src,
+			edesc->pset[i].dst,
+			edesc->pset[i].a_b_cnt,
+			edesc->pset[i].ccnt,
+			edesc->pset[i].src_dst_bidx,
+			edesc->pset[i].src_dst_cidx,
+			edesc->pset[i].link_bcntrld);
+
+		edesc->absync = ret;
+
+		/*
+		 * Enable interrupts for every period because callback
+		 * has to be called for every period.
+		 */
+		edesc->pset[i].opt |= TCINTEN;
+	}
+
+	return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
+}
+
 static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
 {
 	struct edma_chan *echan = data;
@@ -467,24 +605,28 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
 	unsigned long flags;
 	struct edmacc_param p;
 
-	/* Pause the channel */
-	edma_pause(echan->ch_num);
+	edesc = echan->edesc;
+
+	/* Pause the channel for non-cyclic */
+	if (!edesc || (edesc && !edesc->cyclic))
+		edma_pause(echan->ch_num);
 
 	switch (ch_status) {
 	case EDMA_DMA_COMPLETE:
 		spin_lock_irqsave(&echan->vchan.lock, flags);
 
-		edesc = echan->edesc;
 		if (edesc) {
-			if (edesc->processed == edesc->pset_nr) {
+			if (edesc->cyclic) {
+				vchan_cyclic_callback(&edesc->vdesc);
+			} else if (edesc->processed == edesc->pset_nr) {
 				dev_dbg(dev, "Transfer complete, stopping channel %d\n", ch_num);
 				edma_stop(echan->ch_num);
 				vchan_cookie_complete(&edesc->vdesc);
+				edma_execute(echan);
 			} else {
 				dev_dbg(dev, "Intermediate transfer complete on channel %d\n", ch_num);
+				edma_execute(echan);
 			}
-
-			edma_execute(echan);
 		}
 
 		spin_unlock_irqrestore(&echan->vchan.lock, flags);
@@ -680,6 +822,7 @@ static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
 			  struct device *dev)
 {
 	dma->device_prep_slave_sg = edma_prep_slave_sg;
+	dma->device_prep_dma_cyclic = edma_prep_dma_cyclic;
 	dma->device_alloc_chan_resources = edma_alloc_chan_resources;
 	dma->device_free_chan_resources = edma_free_chan_resources;
 	dma->device_issue_pending = edma_issue_pending;