Re: [PATCH] ARM: tegra: Register host1x node with iommu binding on tegra124

From: Marcel Ziswiler <marcel.ziswiler@toradex.com>
To: "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"contact@paulk.fr" <contact@paulk.fr>,
	"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
Cc: "jonathanh@nvidia.com" <jonathanh@nvidia.com>,
	"mperttunen@nvidia.com" <mperttunen@nvidia.com>,
	"treding@nvidia.com" <treding@nvidia.com>,
	"swarren@nvidia.com" <swarren@nvidia.com>
Subject: Re: [PATCH] ARM: tegra: Register host1x node with iommu binding on tegra124
Date: Tue, 11 Jul 2017 15:17:46 +0000	[thread overview]
Message-ID: <1499786264.1520.22.camel@toradex.com> (raw)
In-Reply-To: <1499785555.1340.15.camel@paulk.fr>

On Tue, 2017-07-11 at 18:05 +0300, Paul Kocialkowski wrote:
> On Tue, 2017-07-11 at 14:54 +0000, Marcel Ziswiler wrote:
> > On Tue, 2017-07-11 at 11:50 +0300, Paul Kocialkowski wrote:
> > > On Sun, 2017-07-09 at 19:36 +0300, Paul Kocialkowski wrote:
> > > > This registers the host1x node with the SMMU (as HC swgroup) to
> > > > allow
> > > > the host1x code to attach to it. It avoid failing the probe
> > > > sequence,
> > > > which resulted in the tegra drm driver not probing and thus
> > > > nothing
> > > > being displayed on-screen.
> > > 
> > > Fixes: 404bfb78daf3 ("gpu: host1x: Add IOMMU support")
> > > 
> > > > Signed-off-by: Paul Kocialkowski <contact-
> > > > W9ppeneeCTY@public.gmane.org>
> > 
> > Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
> > Tested-on: Apalis TK1, Jetson-TK1
> > 
> > > > ---
> > > >  arch/arm/boot/dts/tegra124.dtsi | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > > 
> > > > diff --git a/arch/arm/boot/dts/tegra124.dtsi
> > > > b/arch/arm/boot/dts/tegra124.dtsi
> > > > index 187a36c6d0fc..b3b89befffeb 100644
> > > > --- a/arch/arm/boot/dts/tegra124.dtsi
> > > > +++ b/arch/arm/boot/dts/tegra124.dtsi
> > > > @@ -85,6 +85,7 @@
> > > >  		clocks = <&tegra_car TEGRA124_CLK_HOST1X>;
> > > >  		resets = <&tegra_car 28>;
> > > >  		reset-names = "host1x";
> > > > +		iommus = <&mc TEGRA_SWGROUP_HC>;
> > > >  
> > > >  		#address-cells = <2>;
> > > >  		#size-cells = <2>;
> > 
> > So I take it we still will need this one moving forward, correct?
> 
> Yes, this one actually enables the IOMMU while the other one handles
> the
> failure to attach the IOMMU without brinding the whole drm driver
> down.
> 
> So it's best to actually make use of the feature!
> 
> > How about tegra30, I guess the same applies there, isn't it? Should
> > I
> > send a patch or are you guys doing that?
> 
> I don't have any tegra hardware aside of tegra124, so that's all I
> can
> contribute to. I don't know if others have looked into the same type
> of
> issue happening on either newer or older platforms.

OK, as we happen to still selling Apalis/Colibri T30 and me having
Beaver as well as Cardhu available for testing I can cook something up,
test and send it along. First tries indicate it working on 4.12 but
somehow crashing during memory allocation on -next. We'll see.

> Cheers,