Re: [PATCH 3/4] arm64: dts: renesas: r8a7796: Add DU device to DT

From: Simon Horman <horms@verge.net.au>
To: Magnus Damm <magnus.damm@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH 3/4] arm64: dts: renesas: r8a7796: Add DU device to DT
Date: Thu, 27 Oct 2016 09:13:48 +0200	[thread overview]
Message-ID: <20161027071348.GC7706@verge.net.au> (raw)
In-Reply-To: <CANqRtoRvvkr-HPTz9qGgxg6SK=FNZbO1gdxCDuxeUeGBzAhQ1g@mail.gmail.com>

On Thu, Oct 27, 2016 at 03:52:44PM +0900, Magnus Damm wrote:
> Hi Simon, everyone,
> 
> On Thu, Oct 20, 2016 at 5:56 PM, Simon Horman <horms@verge.net.au> wrote:
> > On Tue, Oct 18, 2016 at 12:19:26PM +0300, Laurent Pinchart wrote:
> >> Hi Simon,
> >>
> >> On Tuesday 18 Oct 2016 11:05:32 Geert Uytterhoeven wrote:
> >> > On Mon, Oct 17, 2016 at 11:34 PM, Laurent Pinchart wrote:
> >> > > Add the DU device to r8a7796.dtsi in a disabled state.
> >> > >
> >> > > Signed-off-by: Laurent Pinchart
> >> > > <laurent.pinchart+renesas@ideasonboard.com>
> >> >
> >> > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> >>
> >> Could you please pick patches 1/4 to 3/4 from this series and apply them to
> >> your tree ? For convenience I've pushed them to
> >>
> >>       git://linuxtv.org/pinchartl/media.git drm/r8a7796/dt
> >>
> >> along with patch "arm64: dts: renesas: r8a7795: Remove FCP SoC-specific
> >> compatible strings" that has been acked too. If you pull from that branch
> >> please make sure you skip the top-most patch "arm64: dts: renesas: r8a7796-
> >> salvator-x: Enable DU" for now.
> >
> > Sure, done.
> 
> I think we should hold off with the upstreaming of the DU and VSP
> integration code for now. Sorry for noticing this late, but I thought
> we had already discussed the integration order and that merge of
> non-64-bit capable devices need to be put on hold.
> 
> In particular, not so much the DU device (this patch) but more the VSP
> instances. The reason for that is that VSP devices can only perform
> 32-bit bus mastering without IOMMU. I believe next step for all this
> would be to enable all on-board memory on r8a7796 Salvator-x, but I
> think Geert is working on that.

So you would like to see the following patches dropped?

ee73acb13978 arm64: dts: renesas: r8a7796: Add VSP instances
0a6519d782fd arm64: dts: renesas: r8a7796: Add FCPF and FCPV instances

> Regarding IOMMU support, more effort is needed to get the IPMMU driver
> with r8a7796 (and r8a7795) support upstream. Some stuff for r8a7795
> exists in renesas-drivers and experimental r8a7796 support as well.
> 
> One issue is that the DU driver itself is not ready to be used with
> IOMMU yet (below patches not upstream yet), and more work is needed as
> well - please see my reply (and prototype patch that fixes the issue
> locally):
> [PATCH 0/6] R-Car DU: Fix IOMMU operation when connected to VSP
> http://www.spinics.net/lists/dri-devel/msg117494.html
> 
> Also, the r8a7796 DU driver code is not yet merged upstream and the
> binding is also not yet documented. So either way you look at it it
> seems a tad early for upstream merge.
> 
> Thanks,
> 
> / magnus
> 