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Message-ID: <3028945.75TnRQEiiW@ws-stein>
Date: Wed, 09 Apr 2014 18:10:11 +0200
From: Alexander Stein <alexander.stein@...tec-electronic.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
David Cohen <david.a.cohen@...ux.intel.com>, wim@...ana.be,
tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
x86@...nel.org, linux-kernel@...r.kernel.org,
linux-watchdog@...r.kernel.org
Subject: Re: [PATCH 2/2] x86: intel-mid: add watchdog platform code for Merrifield
On Wednesday 09 April 2014 08:18:22, Guenter Roeck wrote:
> On Wed, Apr 09, 2014 at 04:03:14PM +0200, Alexander Stein wrote:
> > On Wednesday 09 April 2014 14:58:48, One Thousand Gnomes wrote:
> > > > I'm getting curious: How can I use device-tree on x86(_64)?
> > > > Reading the dependencies from CONFIG_OF it can only be used on 32bit systems with some special hardware bases.
> > > > So, how to use otherwise?
> > >
> > > There isn't any fundamental thing tying device tree to a given
> > > architecture or 32bitness, it's just that sane PC architectures use ACPI
> > > to enumerate devices, and/or have a discoverable bus architecture.
> > >
> > > Some of the phones don't so this now becoems a point of consideration. In
> > > fact it's already also used on CE4100 (which is an embedded media SoC
> > > found in some TV devices and set-top boxes) and on the OLPC (One laptop
> > > per child). There is no intrinsic reason it couldn't be used in other x86
> > > special cases.
> > >
> > > If its PC shaped however it probably has ACPI and ACPI and DT are not a
> > > 1:1 mapping. ACPI has method invocations, and various firmware provided
> > > interfaces such as the EC, Device tree is better at some other bits.
> >
> > Yep, like SPI devices on embedded x86 hardware.
> >
> > > Converting the phones to embedded device tree rather than adding a
> > > billion little platform files on the other hand seems to me like a
> > > no-brainer.
> >
> > I found http://thread.gmane.org/gmane.linux.drivers.devicetree/4475. Why didn't that get into mainline?
> >
>
> Isn't that patch set in mainline ?
Oh, I see that this patch didn't get included 1:1 as shown in that link. I only checked USE_OF in arch/x86/Kconfig which didn't get included that way :(
> We are working on a patch set to make DT support on x86 more
> widely available. Thierry Reding did some work on it a while ago.
> Some of it is upstream, other parts are available in
> https://github.com/avionic-design/linux/commits/medatom/master
>
> We'll see if and what will be accepted upstream.
As far as I can see, CONFIG_OF is only selected if a specific hardware is enabled.
Regards,
Alexander
--
Dipl.-Inf. Alexander Stein
SYS TEC electronic GmbH
Am Windrad 2
08468 Heinsdorfergrund
Tel.: 03765 38600-1156
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Email: alexander.stein@...tec-electronic.com
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