DMAEngine: Define interleaved transfer request api
authorJassi Brar <jaswinder.singh@linaro.org>
Thu, 13 Oct 2011 07:03:30 +0000 (12:03 +0530)
committerVinod Koul <vinod.koul@linux.intel.com>
Fri, 18 Nov 2011 06:46:24 +0000 (11:46 +0530)
commitb14dab792dee3245b628e046d80a7fad5573fea6
treec77574d19be7c150b57bd9a9b0184580c733621b
parente0d23ef29ed637dc6bd739f590985746d9ad9caa
DMAEngine: Define interleaved transfer request api

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>
Documentation/dmaengine.txt
drivers/dma/dmaengine.c
include/linux/dmaengine.h