1 files changed, 125 insertions, 42 deletions

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 5f3e532436ee..3519111c566b 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -56,6 +56,7 @@ struct edma_desc {
 	struct list_head		node;
 	int				absync;
 	int				pset_nr;
+	int				processed;
 	struct edmacc_param		pset[0];
 };
 
@@ -69,6 +70,7 @@ struct edma_chan {
 	int				ch_num;
 	bool				alloced;
 	int				slot[EDMA_MAX_SLOTS];
+	int				missed;
 	struct dma_slave_config		cfg;
 };
 
@@ -104,22 +106,34 @@ static void edma_desc_free(struct virt_dma_desc *vdesc)
 /* Dispatch a queued descriptor to the controller (caller holds lock) */
 static void edma_execute(struct edma_chan *echan)
 {
-	struct virt_dma_desc *vdesc = vchan_next_desc(&echan->vchan);
+	struct virt_dma_desc *vdesc;
 	struct edma_desc *edesc;
-	int i;
-
-	if (!vdesc) {
-		echan->edesc = NULL;
-		return;
+	struct device *dev = echan->vchan.chan.device->dev;
+	int i, j, left, nslots;
+
+	/* If either we processed all psets or we're still not started */
+	if (!echan->edesc ||
+	    echan->edesc->pset_nr == echan->edesc->processed) {
+		/* Get next vdesc */
+		vdesc = vchan_next_desc(&echan->vchan);
+		if (!vdesc) {
+			echan->edesc = NULL;
+			return;
+		}
+		list_del(&vdesc->node);
+		echan->edesc = to_edma_desc(&vdesc->tx);
 	}
 
-	list_del(&vdesc->node);
+	edesc = echan->edesc;
 
-	echan->edesc = edesc = to_edma_desc(&vdesc->tx);
+	/* Find out how many left */
+	left = edesc->pset_nr - edesc->processed;
+	nslots = min(MAX_NR_SG, left);
 
 	/* Write descriptor PaRAM set(s) */
-	for (i = 0; i < edesc->pset_nr; i++) {
-		edma_write_slot(echan->slot[i], &edesc->pset[i]);
+	for (i = 0; i < nslots; i++) {
+		j = i + edesc->processed;
+		edma_write_slot(echan->slot[i], &edesc->pset[j]);
 		dev_dbg(echan->vchan.chan.device->dev,
 			"\n pset[%d]:\n"
 			"  chnum\t%d\n"
@@ -132,24 +146,50 @@ static void edma_execute(struct edma_chan *echan)
 			"  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);
+			j, echan->ch_num, echan->slot[i],
+			edesc->pset[j].opt,
+			edesc->pset[j].src,
+			edesc->pset[j].dst,
+			edesc->pset[j].a_b_cnt,
+			edesc->pset[j].ccnt,
+			edesc->pset[j].src_dst_bidx,
+			edesc->pset[j].src_dst_cidx,
+			edesc->pset[j].link_bcntrld);
 		/* Link to the previous slot if not the last set */
-		if (i != (edesc->pset_nr - 1))
+		if (i != (nslots - 1))
 			edma_link(echan->slot[i], echan->slot[i+1]);
-		/* Final pset links to the dummy pset */
-		else
-			edma_link(echan->slot[i], echan->ecc->dummy_slot);
 	}
 
-	edma_start(echan->ch_num);
+	edesc->processed += nslots;
+
+	/*
+	 * If this is either the last set in a set of SG-list transactions
+	 * 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);
+
+	edma_resume(echan->ch_num);
+
+	if (edesc->processed <= MAX_NR_SG) {
+		dev_dbg(dev, "first transfer starting %d\n", echan->ch_num);
+		edma_start(echan->ch_num);
+	}
+
+	/*
+	 * This happens due to setup times between intermediate transfers
+	 * in long SG lists which have to be broken up into transfers of
+	 * MAX_NR_SG
+	 */
+	if (echan->missed) {
+		dev_dbg(dev, "missed event in execute detected\n");
+		edma_clean_channel(echan->ch_num);
+		edma_stop(echan->ch_num);
+		edma_start(echan->ch_num);
+		edma_trigger_channel(echan->ch_num);
+		echan->missed = 0;
+	}
 }
 
 static int edma_terminate_all(struct edma_chan *echan)
@@ -222,9 +262,9 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 	enum dma_slave_buswidth dev_width;
 	u32 burst;
 	struct scatterlist *sg;
-	int i;
 	int acnt, bcnt, ccnt, src, dst, cidx;
 	int src_bidx, dst_bidx, src_cidx, dst_cidx;
+	int i, nslots;
 
 	if (unlikely(!echan || !sgl || !sg_len))
 		return NULL;
@@ -247,12 +287,6 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 		return NULL;
 	}
 
-	if (sg_len > MAX_NR_SG) {
-		dev_err(dev, "Exceeded max SG segments %d > %d\n",
-			sg_len, MAX_NR_SG);
-		return NULL;
-	}
-
 	edesc = kzalloc(sizeof(*edesc) + sg_len *
 		sizeof(edesc->pset[0]), GFP_ATOMIC);
 	if (!edesc) {
@@ -262,17 +296,24 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 
 	edesc->pset_nr = sg_len;
 
-	for_each_sg(sgl, sg, sg_len, i) {
-		/* Allocate a PaRAM slot, if needed */
+	/* Allocate a PaRAM slot, if needed */
+	nslots = min_t(unsigned, MAX_NR_SG, sg_len);
+
+	for (i = 0; i < nslots; i++) {
 		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");
+				kfree(edesc);
 				return NULL;
 			}
 		}
+	}
+
+	/* Configure PaRAM sets for each SG */
+	for_each_sg(sgl, sg, sg_len, i) {
 
 		acnt = dev_width;
 
@@ -330,6 +371,12 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 		/* Configure A or AB synchronized transfers */
 		if (edesc->absync)
 			edesc->pset[i].opt |= SYNCDIM;
+
+		/* If this is the last in a current SG set of transactions,
+		   enable interrupts so that next set is processed */
+		if (!((i+1) % MAX_NR_SG))
+			edesc->pset[i].opt |= TCINTEN;
+
 		/* If this is the last set, enable completion interrupt flag */
 		if (i == sg_len - 1)
 			edesc->pset[i].opt |= TCINTEN;
@@ -355,27 +402,65 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
 	struct device *dev = echan->vchan.chan.device->dev;
 	struct edma_desc *edesc;
 	unsigned long flags;
+	struct edmacc_param p;
 
-	/* Stop the channel */
-	edma_stop(echan->ch_num);
+	/* Pause the channel */
+	edma_pause(echan->ch_num);
 
 	switch (ch_status) {
 	case DMA_COMPLETE:
-		dev_dbg(dev, "transfer complete on channel %d\n", ch_num);
-
 		spin_lock_irqsave(&echan->vchan.lock, flags);
 
 		edesc = echan->edesc;
 		if (edesc) {
+			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);
+			} else {
+				dev_dbg(dev, "Intermediate transfer complete on channel %d\n", ch_num);
+			}
+
 			edma_execute(echan);
-			vchan_cookie_complete(&edesc->vdesc);
 		}
 
 		spin_unlock_irqrestore(&echan->vchan.lock, flags);
 
 		break;
 	case DMA_CC_ERROR:
-		dev_dbg(dev, "transfer error on channel %d\n", ch_num);
+		spin_lock_irqsave(&echan->vchan.lock, flags);
+
+		edma_read_slot(EDMA_CHAN_SLOT(echan->slot[0]), &p);
+
+		/*
+		 * Issue later based on missed flag which will be sure
+		 * to happen as:
+		 * (1) we finished transmitting an intermediate slot and
+		 *     edma_execute is coming up.
+		 * (2) or we finished current transfer and issue will
+		 *     call edma_execute.
+		 *
+		 * Important note: issuing can be dangerous here and
+		 * lead to some nasty recursion when we are in a NULL
+		 * slot. So we avoid doing so and set the missed flag.
+		 */
+		if (p.a_b_cnt == 0 && p.ccnt == 0) {
+			dev_dbg(dev, "Error occurred, looks like slot is null, just setting miss\n");
+			echan->missed = 1;
+		} else {
+			/*
+			 * The slot is already programmed but the event got
+			 * missed, so its safe to issue it here.
+			 */
+			dev_dbg(dev, "Error occurred but slot is non-null, TRIGGERING\n");
+			edma_clean_channel(echan->ch_num);
+			edma_stop(echan->ch_num);
+			edma_start(echan->ch_num);
+			edma_trigger_channel(echan->ch_num);
+		}
+
+		spin_unlock_irqrestore(&echan->vchan.lock, flags);
+
 		break;
 	default:
 		break;
@@ -502,8 +587,6 @@ static enum dma_status edma_tx_status(struct dma_chan *chan,
 	} else if (echan->edesc && echan->edesc->vdesc.tx.cookie == cookie) {
 		struct edma_desc *edesc = echan->edesc;
 		txstate->residue = edma_desc_size(edesc);
-	} else {
-		txstate->residue = 0;
 	}
 	spin_unlock_irqrestore(&echan->vchan.lock, flags);
 
@@ -667,6 +750,6 @@ static void __exit edma_exit(void)
 }
 module_exit(edma_exit);
 
-MODULE_AUTHOR("Matt Porter <mporter@ti.com>");
+MODULE_AUTHOR("Matt Porter <matt.porter@linaro.org>");
 MODULE_DESCRIPTION("TI EDMA DMA engine driver");
 MODULE_LICENSE("GPL v2");