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DMAEngine: Define interleaved transfer request api

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Define a new api that could be used for doing fancy data transfers
like interleaved to contiguous copy and vice-versa.
Traditional SG_list based transfers tend to be very inefficient in
such cases as where the interleave and chunk are only a few bytes,
which call for a very condensed api to convey pattern of the transfer.
This api supports all 4 variants of scatter-gather and contiguous transfer.

Of course, neither can this api help transfers that don't lend to DMA by
nature, i.e, scattered tiny read/writes with no periodic pattern.

Also since now we support SLAVE channels that might not provide
device_prep_slave_sg callback but device_prep_interleaved_dma,
remove the BUG_ON check.

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Acked-by: Barry Song <Baohua.Song@csr.com>
[renamed dmaxfer_template to dma_interleaved_template
 did fixup after the enum dma_transfer_merge]
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
This commit is contained in:
Jassi Brar
2011-10-13 12:33:30 +05:30
committed by Vinod Koul
parent e0d23ef29e
commit b14dab792d
3 changed files with 85 additions and 5 deletions
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4
drivers/dma/dmaengine.c
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@@ -693,12 +693,12 @@ int dma_async_device_register(struct dma_device *device)
!device->device_prep_dma_interrupt);
BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
!device->device_prep_dma_sg);
BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
!device->device_prep_slave_sg);
BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
!device->device_prep_dma_cyclic);
BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
!device->device_control);
BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
!device->device_prep_interleaved_dma);
BUG_ON(!device->device_alloc_chan_resources);
BUG_ON(!device->device_free_chan_resources);