Re: [PATCH] mmc: mmci: Add new VE MMCI variant

Pawel Moll
2013-01-24T12:36:12Z

Hello Ulf,

On Fri, 2012-12-21 at 11:05 +0000, Ulf Hansson wrote:
> On 14 December 2012 16:38, Pawel Moll <pawel.moll@arm.com> wrote:
> > The Versatile Express IOFPGA as shipped on VECD 5.0 (bitfiles v108/208
> > and v116/216) contains a modified version of the PL180 MMCI, with
> > PeriphID Configuration value changed to 0x2.
> >
> > This version adds an optional "hardware flow control" feature. When
> > enabled MMC card clock will be automatically disabled when FIFO is
> > about to over/underflow and re-enabled once the host retrieved some
> > data. This makes the controller immune to over/underrun errors caused
> > by big interrupt handling latencies.
> >
> > This patch adds relevant device variant in the driver.
> >
> > Signed-off-by: Pawel Moll <pawel.moll@arm.com>

> So enabling this in the variant will also effect how the clock is
> being set/gated when the clock freq is 0.
>
> Please have a look at "mmc: mmci: Gate the clock when freq is 0", a
> patch I sent out as of 12 dec.
> That patch is using the power register to gate the clock. Will that
> work with this new version of the PL180 as well? If not, that patch
> must be reworked.

I'm not quite sure what you meant here, but I see that v2 of your patch
does whatever it is supposed to do to ST variants only, so I guess your
objections don't apply any more?

Cheers!

Pawel