[RFC 23/34] dmaengine: PL08x: re-jig the starting of txds

[Linus Walleij]

On Fri, Jun 1, 2012 at 12:52 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> [Me]
>> > +                                */
>> > +                               spin_lock(&waiting->lock);
>> > +                               pl08x_start_next_txd(waiting);
>> > +                               spin_unlock(&waiting->lock);
>>
>> I've seen this construct in the past and have no better suggestions...
>
> I have no way to test whether my statement is true as I can't get enough
> DMA engine usage through the PL011 transmit support to check what happens.
> So the statement is purely theoretical.

Doesn't memcpy work on the Versatile?

What I did to stress the PB11MPcore was to compile in the DMAengine
test client and torture the DMAC with a bunch of parallell memcpy()
threads causing it to fail channel allocation and other nasty stuff,
then put the console on DMA and pour a lot of text in and out of the
console on top of that.

Yours,
Linus Walleij