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Message-ID: <1442915675-7121-4-git-send-email-peter.ujfalusi@ti.com>
Date: Tue, 22 Sep 2015 12:54:14 +0300
From: Peter Ujfalusi <peter.ujfalusi@...com>
To: <vinod.koul@...el.com>, <nsekhar@...com>, <linux@....linux.org.uk>
CC: <olof@...om.net>, <arnd@...db.de>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
<dmaengine@...r.kernel.org>
Subject: [PATCH v3 03/24] dmaengine: edma: Simplify and optimize the edma_execute path
The code path in edma_execute() and edma_callback() can be simplified
and make it more optimal.
There is not need to call in to edma_execute() when the transfer
has been finished for example.
Also the handling of missed/first or next batch of paRAMs can
be done in a more optimal way.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
drivers/dma/edma.c | 76 +++++++++++++++++++++---------------------------------
1 file changed, 29 insertions(+), 47 deletions(-)
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 3e5d4f193005..19fa49d6f555 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -154,15 +154,11 @@ static void edma_execute(struct edma_chan *echan)
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 */
+ if (!echan->edesc) {
+ /* Setup is needed for the first transfer */
vdesc = vchan_next_desc(&echan->vchan);
- if (!vdesc) {
- echan->edesc = NULL;
+ if (!vdesc)
return;
- }
list_del(&vdesc->node);
echan->edesc = to_edma_desc(&vdesc->tx);
}
@@ -220,28 +216,26 @@ static void edma_execute(struct edma_chan *echan)
echan->ecc->dummy_slot);
}
- if (edesc->processed <= MAX_NR_SG) {
- dev_dbg(dev, "first transfer starting on channel %d\n",
- echan->ch_num);
- edma_start(echan->ch_num);
- } else {
- dev_dbg(dev, "chan: %d: completed %d elements, resuming\n",
- echan->ch_num, edesc->processed);
- edma_resume(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) {
+ /*
+ * 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
+ */
dev_dbg(dev, "missed event on channel %d\n", echan->ch_num);
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;
+ } else if (edesc->processed <= MAX_NR_SG) {
+ dev_dbg(dev, "first transfer starting on channel %d\n",
+ echan->ch_num);
+ edma_start(echan->ch_num);
+ } else {
+ dev_dbg(dev, "chan: %d: completed %d elements, resuming\n",
+ echan->ch_num, edesc->processed);
+ edma_resume(echan->ch_num);
}
}
@@ -259,20 +253,17 @@ static int edma_terminate_all(struct dma_chan *chan)
* echan->edesc is NULL and exit.)
*/
if (echan->edesc) {
- int cyclic = echan->edesc->cyclic;
-
+ edma_stop(echan->ch_num);
+ /* Move the cyclic channel back to default queue */
+ if (echan->edesc->cyclic)
+ edma_assign_channel_eventq(echan->ch_num,
+ EVENTQ_DEFAULT);
/*
* free the running request descriptor
* since it is not in any of the vdesc lists
*/
edma_desc_free(&echan->edesc->vdesc);
-
echan->edesc = NULL;
- edma_stop(echan->ch_num);
- /* Move the cyclic channel back to default queue */
- if (cyclic)
- edma_assign_channel_eventq(echan->ch_num,
- EVENTQ_DEFAULT);
}
vchan_get_all_descriptors(&echan->vchan, &head);
@@ -725,41 +716,33 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
edesc = echan->edesc;
- /* Pause the channel for non-cyclic */
- if (!edesc || (edesc && !edesc->cyclic))
- edma_pause(echan->ch_num);
-
+ spin_lock(&echan->vchan.lock);
switch (ch_status) {
case EDMA_DMA_COMPLETE:
- spin_lock(&echan->vchan.lock);
-
if (edesc) {
if (edesc->cyclic) {
vchan_cyclic_callback(&edesc->vdesc);
+ goto out;
} else if (edesc->processed == edesc->pset_nr) {
dev_dbg(dev, "Transfer complete, stopping channel %d\n", ch_num);
edesc->residue = 0;
edma_stop(echan->ch_num);
vchan_cookie_complete(&edesc->vdesc);
- edma_execute(echan);
+ echan->edesc = NULL;
} else {
dev_dbg(dev, "Intermediate transfer complete on channel %d\n", ch_num);
+ edma_pause(echan->ch_num);
+
/* Update statistics for tx_status */
edesc->residue -= edesc->sg_len;
edesc->residue_stat = edesc->residue;
edesc->processed_stat = edesc->processed;
-
- edma_execute(echan);
}
+ edma_execute(echan);
}
-
- spin_unlock(&echan->vchan.lock);
-
break;
case EDMA_DMA_CC_ERROR:
- spin_lock(&echan->vchan.lock);
-
edma_read_slot(EDMA_CHAN_SLOT(echan->slot[0]), &p);
/*
@@ -788,13 +771,12 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
edma_start(echan->ch_num);
edma_trigger_channel(echan->ch_num);
}
-
- spin_unlock(&echan->vchan.lock);
-
break;
default:
break;
}
+out:
+ spin_unlock(&echan->vchan.lock);
}
/* Alloc channel resources */
--
2.5.2
--
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