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dma: mv_xor: Add support for DMA_INTERRUPT

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The driver is capable of supporting DMA_INTERRUPT by issuing a dummy 128-byte
transfer. This helps removing a poll in the async_tx stack, replacing it with
a completion interrupt.

Signed-off-by: Lior Amsalem <alior@marvell.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Lior Amsalem
2014-08-27 10:52:55 -03:00
committed by Vinod Koul
parent 37380b980e
commit 22843545b2
2 changed files with 40 additions and 5 deletions
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34
drivers/dma/mv_xor.c
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@@ -538,6 +538,24 @@ mv_xor_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
return mv_xor_prep_dma_xor(chan, dest, &src, 1, len, flags);
}
static struct dma_async_tx_descriptor *
mv_xor_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags)
{
struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
dma_addr_t src, dest;
size_t len;
src = mv_chan->dummy_src_addr;
dest = mv_chan->dummy_dst_addr;
len = MV_XOR_MIN_BYTE_COUNT;
/*
* We implement the DMA_INTERRUPT operation as a minimum sized
* XOR operation with a single dummy source address.
*/
return mv_xor_prep_dma_xor(chan, dest, &src, 1, len, flags);
}
static void mv_xor_free_chan_resources(struct dma_chan *chan)
{
struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
@@ -881,6 +899,10 @@ static int mv_xor_channel_remove(struct mv_xor_chan *mv_chan)
dma_free_coherent(dev, MV_XOR_POOL_SIZE,
mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);
dma_unmap_single(dev, mv_chan->dummy_src_addr,
MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE);
dma_unmap_single(dev, mv_chan->dummy_dst_addr,
MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE);
list_for_each_entry_safe(chan, _chan, &mv_chan->dmadev.channels,
device_node) {
@@ -910,6 +932,16 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
dma_dev = &mv_chan->dmadev;
/*
* These source and destination dummy buffers are used to implement
* a DMA_INTERRUPT operation as a minimum-sized XOR operation.
* Hence, we only need to map the buffers at initialization-time.
*/
mv_chan->dummy_src_addr = dma_map_single(dma_dev->dev,
mv_chan->dummy_src, MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE);
mv_chan->dummy_dst_addr = dma_map_single(dma_dev->dev,
mv_chan->dummy_dst, MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE);
/* allocate coherent memory for hardware descriptors
* note: writecombine gives slightly better performance, but
* requires that we explicitly flush the writes
@@ -934,6 +966,8 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
dma_dev->dev = &pdev->dev;
/* set prep routines based on capability */
if (dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask))
dma_dev->device_prep_dma_interrupt = mv_xor_prep_dma_interrupt;
if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask))
dma_dev->device_prep_dma_memcpy = mv_xor_prep_dma_memcpy;
if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {