Re: [PATCH] arm64: dts: renesas: Add /soc dma-ranges

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Marek Vasut <marek.vasut@gmail.com>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Wolfram Sang <wsa@the-dreams.de>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH] arm64: dts: renesas: Add /soc dma-ranges
Date: Mon, 9 Sep 2019 11:05:36 +0200	[thread overview]
Message-ID: <CAMuHMdUWezNDVv+U=VeryssmSFm79zU-ptuKmMechcWBboV1=w@mail.gmail.com> (raw)
In-Reply-To: <b77e6a66-be14-4f94-c116-788b8fa18b31@gmail.com>

Hi Marek,

On Mon, Sep 9, 2019 at 10:42 AM Marek Vasut <marek.vasut@gmail.com> wrote:
> On 9/9/19 10:19 AM, Geert Uytterhoeven wrote:
> > On Sat, Sep 7, 2019 at 6:16 PM <marek.vasut@gmail.com> wrote:
> >> From: Marek Vasut <marek.vasut+renesas@gmail.com>
> >>
> >> Add dma-ranges property into /soc node to describe the DMA capabilities
> >> of the bus. This is currently needed to translate PCI DMA ranges, which
> >> are limited to 32bit addresses.
> >>
> >> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
> >
> > Thanks for your patch!
> >
> >> NOTE: This is needed for the following patches to work correctly:
> >>       https://patchwork.ozlabs.org/patch/1144870/
> >>       https://patchwork.ozlabs.org/patch/1144871/
> >
> > What happens with the above patches applied, and without this one?
>
> It triggers https://patchwork.kernel.org/patch/11087391/#22811745

Sure. But what does that mean?
PCI devices just not working?
Random memory corruption?
System lockup?
Anything else?

> > As PCI/OF driver patches go in through different trees, is it safe to apply
> > this patch now?
> > Should they go in together?
>
> I didn't get any feedback on the other two patches, but this one here is
> safe to go in either way.
>
> >>  arch/arm64/boot/dts/renesas/r8a7795.dtsi  | 1 +
> >>  arch/arm64/boot/dts/renesas/r8a7796.dtsi  | 1 +
> >>  arch/arm64/boot/dts/renesas/r8a77965.dtsi | 1 +
> >
> > Do we need similar patches for the other R-Car Gen3 and RZ/G2 DTS files?
> > What about R-Car Gen2 and RZ/G1?
> I suspect we need such patches for any ARM64 machine with PCIe with this
> 32bit limitation.

What about R-Car Gen2 and RZ/G1, which are ARM32, with LPAE?

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds