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

[Zhang Wei-r63237]

Hi, Dan,

Thanks! I get it.
It's so lucky we have the same target.
When your patch could be accepted?

Cheers,
Wei. 

> -----Original Message-----
> From: dan.j.williams at gmail.com 
> [mailto:dan.j.williams at gmail.com] On Behalf Of Dan Williams
> Sent: Thursday, July 12, 2007 12:57 AM
> To: Zhang Wei-r63237
> Cc: akpm at linux-foundation.org; paulus at samba.org; 
> galak at kernel.crashing.org; linuxppc-dev at ozlabs.org; 
> linux-kernel at vger.kernel.org; shannon.nelson at intel.com
> Subject: Re: [PATCH 3/4] Extend the DMA-engine API.
> 
> 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:
> http://marc.info/?l=linux-raid&m=118290909528910&w=2
> 
> 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
> following:
> 
> 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)
> tx->tx_submit(tx)
> 
> 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.
> 
> --
> Dan
>