From ed8e3d3a6a0abe71d125c615a92a01a150c53e15 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Tue, 3 Sep 2013 10:02:46 -0500 Subject: [PATCH 2/5] dma: edma: Write out and handle MAX_NR_SG at a given time

Process SG-elements in batches of MAX_NR_SG if they are greater than MAX_NR_SG. Due to this, at any given time only those many slots will be used in the given channel no matter how long the scatter list is. We keep track of how much has been written inorder to process the next batch of elements in the scatter-list and detect completion. For such intermediate transfer completions (one batch of MAX_NR_SG), make use of pause and resume functions instead of start and stop when such intermediate transfer is in progress or completed as we donot want to clear any pending events. Signed-off-by: Joel Fernandes Signed-off-by: Vinod Koul Git-commit: 534070622d2c7fbc5cc929aa93541ccd0ae52ab1 Patch-mainline: v3.12-rc1 Signed-off-by: Matwey V. Kornilov --- drivers/dma/edma.c | 77 ++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 51 insertions(+), 26 deletions(-) diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index e522ad5..f5232bc 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]; }; @@ -104,22 +105,34 @@ 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 +145,31 @@ 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; + + 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); + } } static int edma_terminate_all(struct edma_chan *echan) @@ -368,19 +388,24 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data) struct edma_desc *edesc; unsigned long flags; - /* 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); -- 1.8.1.4 -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org