[PATCH 3/4] Extend the DMA-engine API.

Dan Williams dan.j.williams at intel.com
Thu Jul 12 02:56:31 EST 2007

On 7/11/07, Zhang Wei-r63237 <Wei.Zhang at freescale.com> wrote:
> Hi, Dan,
> Do you mention here: http://marc.info/?l=linux-raid&m=118290909614463&w=2 ?
> I see the async_tx is located at crypto/ of the above page, but my patch is for DMA engine in drivers/dma and for DMA engine driver.
> Thanks!
> Wei.

Hi Wei,

I was referring to:

async_tx is an api that exploits the raw capabilities of the new
dmaengine interface.  For your case when the existing api calls do not
provide the proper interface you can open code something like the

tx = dev->device_prep_dma_<operation>(chan, len, int_flag)
tx->tx_set_src(dma_addr_t, tx, index /* for multi-source ops */)
tx->tx_set_dest(dma_addr_t, tx, index)

The expectation is that the most common usages of dmaengines will use
async_tx calls, or the 'dma_async_memcpy_foo_to_bar' helper routines.


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