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path: root/drivers/dma/edma.c
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Diffstat (limited to 'drivers/dma/edma.c')
-rw-r--r--drivers/dma/edma.c164
1 files changed, 123 insertions, 41 deletions
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 5f3e532436ee..ff50ff4c6a57 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) {
@@ -262,8 +296,10 @@ 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),
@@ -273,6 +309,10 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
return NULL;
}
}
+ }
+
+ /* Configure PaRAM sets for each SG */
+ for_each_sg(sgl, sg, sg_len, i) {
acnt = dev_width;
@@ -330,6 +370,12 @@ 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 +401,65 @@ 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 +586,6 @@ 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);