Re: Onboard SD card doesn't work anymore after the 'mmc-v5.4-2' updates

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Christoph Hellwig <hch@infradead.org>, Rob Herring <robh+dt@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	mad skateman <madskateman@gmail.com>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	Paul Mackerras <paulus@samba.org>,
	"R.T.Dickinson" <rtd2@xtra.co.nz>,
	Christian Zigotzky <chzigotzky@xenosoft.de>,
	"contact@a-eon.com" <contact@a-eon.com>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Christian Zigotzky <info@xenosoft.de>
Subject: Re: Onboard SD card doesn't work anymore after the 'mmc-v5.4-2' updates
Date: Mon, 28 Oct 2019 19:47:01 +1100	[thread overview]
Message-ID: <e68c5f8d73fbf1841531bf07eef0132d409e91b3.camel@kernel.crashing.org> (raw)
In-Reply-To: <20191026063918.GA24015@infradead.org>

On Fri, 2019-10-25 at 23:39 -0700, Christoph Hellwig wrote:
> On Fri, Oct 25, 2019 at 05:28:45PM -0500, Rob Herring wrote:
> > This doesn't work?:
> > 
> >         if (IS_ENABLED(CONFIG_PPC) || of_dma_is_coherent(dev-
> > >of_node))
> >                 value |= ESDHC_DMA_SNOOP;
> >         else
> >                 value &= ~ESDHC_DMA_SNOOP;
> > 
> > While I said use the compatibles, using the kconfig symbol is
> > easier
> > than sorting out which compatibles are PPC SoCs. Though if that's
> > already done elsewhere in the driver, you could set a flag and use
> > that here. I'd be surprised if this was the only difference between
> > ARM and PPC SoCs for this block.
> 
> I think the right thing is a Kconfig variable that the architectures
> selects which says if OF is by default coherent or incoherent, and
> then use that in of_dma_is_coherent.

That too. We could also define properties for both ways so we can
override the default either way.

Cheers,
Ben.