Re: [PATCH v3 09/10] dmaengine: dw: Introduce max burst length hw config

From: Andy Shevchenko
Date: Thu May 28 2020 - 16:38:49 EST


On Thu, May 28, 2020 at 6:43 PM Serge Semin
<Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, May 28, 2020 at 05:52:24PM +0300, Andy Shevchenko wrote:
> > On Wed, May 27, 2020 at 01:50:20AM +0300, Serge Semin wrote:

...

> > Perhaps,
> >
> > /* DesignWare DMA supports burst value from 0 */
> > caps->min_burst = 0;
>
> Regarding min_burst being zero. I don't fully understand what it means.
> It means no burst or burst with minimum length or what?
> In fact DW DMA burst length starts from 1. Remember the burst-length run-time
> parameter we were arguing about? Anyway the driver makes sure that both
> 0 and 1 requested burst length are setup as burst length of 1 in the
> CTLx.SRC_MSIZE, CTLx.DST_MSIZE fields.

Yeah, I also thought about it after I sent a message. 1 sounds better.

--
With Best Regards,
Andy Shevchenko