1 files changed, 49 insertions, 1 deletions

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 4c1c258a5b54..2966ef06c477 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -70,6 +70,7 @@ struct edma_chan {
         int                             ch_num;
         bool                            alloced;
         int                             slot[EDMA_MAX_SLOTS];
+        int                             missed;
         struct dma_slave_config         cfg;
 };
 
@@ -170,6 +171,20 @@ static void edma_execute(struct edma_chan *echan)
                 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)
@@ -387,6 +402,7 @@ 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;
 
         /* Pause the channel */
         edma_pause(echan->ch_num);
@@ -412,7 +428,39 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
 
                 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;