Subject: [PATCH V2 6/6] spi/spi-pl022: Request/free DMA channels as and when required.

From: [email-masked] (viresh kumar)
Date: Wed, 10 Aug 2011 14:59:31 +0530

On 08/10/2011 02:30 PM, Russell King - ARM Linux wrote:
>> > They must be allocated when they are required and must be freed after we are
>> > done with transfers. So that they can be used by other users.
> Which DMA engine driver requires this?
> 

dw_dmac.c

> Normally, when we have DMA engine drivers with multiple request signals,
> the slave peripheral side publishes several virtual channels which are
> claimed by the peripheral drivers.  This (amongst other things) allows
> the peripheral drivers to hold claim to one of the virtual channels
> all the time that it's required.

If users of DMA expect DMA engine drivers to work this way, then we should
have this mentioned clearly in DMA slave documentation.

@Dan/Vinod: What do you say?

-- 
viresh