[PATCH] dmaengine: edma: Add DMA memcpy support

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[PATCH] dmaengine: edma: Add DMA memcpy support

Joel Fernandes
We add DMA memcpy support to EDMA driver. Successful tests performed using
dmatest kernel module. Copy alignment is set to DMA_SLAVE_BUSWIDTH_4_BYTES and
users must ensure length is aligned so that copy is performed fully.

Signed-off-by: Joel Fernandes <[hidden email]>
---
 drivers/dma/edma.c |   51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 25a75e2..072f642 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -378,6 +378,11 @@ static int edma_config_pset(struct dma_chan *chan, struct edmacc_param *pset,
  src_cidx = 0;
  dst_bidx = acnt;
  dst_cidx = cidx;
+ } else if (direction == DMA_MEM_TO_MEM)  {
+ src_bidx = acnt;
+ src_cidx = cidx;
+ dst_bidx = acnt;
+ dst_cidx = cidx;
  } else {
  dev_err(dev, "%s: direction not implemented yet\n", __func__);
  return -EINVAL;
@@ -498,6 +503,44 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
  return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
 }
 
+struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
+ struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+ size_t len, unsigned long tx_flags)
+{
+ int ret;
+ struct edma_desc *edesc;
+ struct device *dev = chan->device->dev;
+ struct edma_chan *echan = to_edma_chan(chan);
+
+ if (unlikely(!echan || !len))
+ return NULL;
+
+ edesc = kzalloc(sizeof(*edesc) + sizeof(edesc->pset[0]), GFP_ATOMIC);
+ if (!edesc) {
+ dev_dbg(dev, "Failed to allocate a descriptor\n");
+ return NULL;
+ }
+
+ edesc->pset_nr = 1;
+
+ ret = edma_config_pset(chan, &edesc->pset[0], src, dest, 1,
+       DMA_SLAVE_BUSWIDTH_4_BYTES, len, DMA_MEM_TO_MEM);
+ if (ret < 0)
+ return NULL;
+
+ edesc->absync = ret;
+
+ /*
+ * Enable intermediate transfer chaining to re-trigger channel
+ * on completion of every TR, and enable transfer-completion
+ * interrupt on completion of the whole transfer.
+ */
+ edesc->pset[0].opt |= ITCCHEN;
+ edesc->pset[0].opt |= TCINTEN;
+
+ return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
+}
+
 static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
  struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
  size_t period_len, enum dma_transfer_direction direction,
@@ -875,6 +918,7 @@ static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
 {
  dma->device_prep_slave_sg = edma_prep_slave_sg;
  dma->device_prep_dma_cyclic = edma_prep_dma_cyclic;
+ dma->device_prep_dma_memcpy = edma_prep_dma_memcpy;
  dma->device_alloc_chan_resources = edma_alloc_chan_resources;
  dma->device_free_chan_resources = edma_free_chan_resources;
  dma->device_issue_pending = edma_issue_pending;
@@ -883,6 +927,12 @@ static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
  dma->device_slave_caps = edma_dma_device_slave_caps;
  dma->dev = dev;
 
+ /*
+ * code using dma memcpy must make sure alignment of
+ * length is at dma->copy_align boundary.
+ */
+ dma->copy_align = DMA_SLAVE_BUSWIDTH_4_BYTES;
+
  INIT_LIST_HEAD(&dma->channels);
 }
 
@@ -911,6 +961,7 @@ static int edma_probe(struct platform_device *pdev)
  dma_cap_zero(ecc->dma_slave.cap_mask);
  dma_cap_set(DMA_SLAVE, ecc->dma_slave.cap_mask);
  dma_cap_set(DMA_CYCLIC, ecc->dma_slave.cap_mask);
+ dma_cap_set(DMA_MEMCPY, ecc->dma_slave.cap_mask);
 
  edma_dma_init(ecc, &ecc->dma_slave, &pdev->dev);
 
--
1.7.9.5

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Re: [PATCH] dmaengine: edma: Add DMA memcpy support

Vinod Koul-3
On Fri, Apr 18, 2014 at 09:50:33PM -0500, Joel Fernandes wrote:
> We add DMA memcpy support to EDMA driver. Successful tests performed using
> dmatest kernel module. Copy alignment is set to DMA_SLAVE_BUSWIDTH_4_BYTES and
> users must ensure length is aligned so that copy is performed fully.

Applied, thanks

--
~Vinod
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