diff options
Diffstat (limited to 'drivers/dma')
-rw-r--r-- | drivers/dma/edma.c | 50 |
1 files changed, 49 insertions, 1 deletions
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 4c1c258..2966ef0 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; |