Re: [PATCHv4] DMAEngine: Define interleaved transfer request api

[Jassi Brar]

On 10 October 2011 21:32, Vinod Koul <vinod.koul@xxxxxxxxx> wrote:
> On Mon, 2011-10-10 at 16:46 +0530, Jassi Brar wrote:
>> On 10 October 2011 16:15, Vinod Koul <vinod.koul@xxxxxxxxx> wrote:
>> >
>> > But I am fine if we find a common ground and merge the two where dmac
>> > can cleanly identify direction and mode it is operating.
>> >
>> The client would set the xfer_direction and dmac would interpret as
>>
>> enum xfer_direction {
>>      MEM_TO_MEM,   ->  Async/Memcpy mode
>>      MEM_TO_DEV,    ->  Slave mode & From Memory to Device
>>      DEV_TO_MEM,    ->  Slave mode & From Device to Memory
>>      DEV_TO_DEV,     ->  Slave mode & From Device to Device
>> }
>>
>> How could it get any cleaner?
> Consider the case of a dmac driver which supports interleaved dma as
> well as memcpy and slave
> It needs to interpret dma_data_direction for later cases and
> xfer_direction for former ones.
dma_data_direction is the mapping attribute of a buffer and is not meant to
tell type of source and destination of a transfer.
xfer_direction is meant for that purpose.
So I'd rather convert device_prep_dma_cyclic and device_prep_slave_sg
to use xfer_direction.
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