Re: [PATCH 01/10] spi: dw: Add support for polled operation via no IRQ specified in DT

From: Serge Semin
Date: Thu May 14 2020 - 09:04:16 EST


Hi Mark

On Wed, May 13, 2020 at 03:20:50PM +0100, Mark Brown wrote:
> On Wed, May 13, 2020 at 04:00:22PM +0200, Lars Povlsen wrote:
> > With this change a SPI controller can be added without having a IRQ
> > associated, and causing all transfers to be polled. For SPI controllers
> > without DMA, this can significantly improve performance by less
> > interrupt handling overhead.
>
> This overlaps substantially with some work that Serge Semin (CCed) has
> in progress, please coordinate with him.

Thanks for copying me these mails. I haven't been Cc'ed in the series and
hasn't been subscribed to the SPI mailing list, so I would have definitely
missed that.

I would like to coordinate my efforts with Lars. I'll have the patchset reviewed
soon in addition providing my comments/suggestions of how to make it useful for
both mine and Lars solution.

One thing I can tell about the mem_ops he implemented, is that they aren't
mem_ops, but dirmap (as you remember it's also implemented in my code, but with
alignment specific), and the exec_mem_op partly consists of a code, which belong
to the supports_op() callback. The rest of my comments will be inlined in the
patches.

-Sergey