From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/6] ARM: add Highbank core platform support
Date: Fri, 19 Aug 2011 15:45:53 +0200 [thread overview]
Message-ID: <201108191545.54223.arnd@arndb.de> (raw)
In-Reply-To: <20110819085647.GA2046@arm.com>
On Friday 19 August 2011, Dave Martin wrote:
> > > +static void __init highbank_map_io(void)
> > > +{
> > > + unsigned long base;
> > > +
> > > + /* Get SCU base */
> > > + asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
> > > +
> > > + highbank_io_desc[0].pfn = __phys_to_pfn(base);
> > > + iotable_init(highbank_io_desc, ARRAY_SIZE(highbank_io_desc));
> > > +}
> > > +
> > It's a great demo that we can get this base address from CA9 itself.
> > However I'm wondering if we have to do so, since this address should
> > be known for given SoC. Can we put this known base into device tree
> > and map it when needed? In that case, we can save another static
> > mapping.
>
> Since device tree is mainly about providing data to describe system
> components that are not discoverable, maybe it is better after all
> not to put this address in the device tree.
>
> Discovery feels like the best approach, where possible.
It's a bit silly to leave it out of the device tree when you otherwise
describe all major components.
However, I agree that if you can probe the value from hardware,
there is no need to read it from there.
Arnd
next prev parent reply other threads:[~2011-08-19 13:45 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-16 20:34 [PATCH 0/6] Initial Calxeda Highbank support Rob Herring
2011-08-16 20:34 ` [PATCH 1/6] ARM: highbank: add devicetree source Rob Herring
2011-08-17 7:27 ` Shawn Guo
2011-08-17 13:49 ` Rob Herring
2011-08-17 14:51 ` Shawn Guo
2011-08-20 18:32 ` Rob Herring
2011-08-17 17:52 ` Will Deacon
2011-08-20 18:29 ` Rob Herring
2011-08-17 9:27 ` Mark Rutland
[not found] ` <4e4b8979.533fd80a.2ff3.1626SMTPIN_ADDED@mx.google.com>
2011-08-17 14:08 ` Rob Herring
2011-08-17 14:34 ` Will Deacon
2011-08-20 9:51 ` Shawn Guo
2011-08-20 18:19 ` Rob Herring
2011-08-16 20:34 ` [PATCH 2/6] ARM: add Highbank core platform support Rob Herring
2011-08-16 22:19 ` Jamie Iles
2011-08-25 2:19 ` Rob Herring
2011-08-17 7:43 ` Russell King - ARM Linux
2011-08-18 15:34 ` Arnd Bergmann
2011-08-18 15:40 ` Russell King - ARM Linux
2011-08-19 14:11 ` Arnd Bergmann
2011-08-20 19:24 ` Rob Herring
2011-08-20 23:05 ` Russell King - ARM Linux
2011-08-20 18:44 ` Rob Herring
2011-08-25 2:45 ` Rob Herring
2011-08-25 4:03 ` Shawn Guo
2011-08-25 15:59 ` Arnd Bergmann
2011-08-25 16:02 ` Arnd Bergmann
2011-08-25 18:03 ` Rob Herring
2011-08-25 21:44 ` Arnd Bergmann
2011-08-19 6:43 ` Shawn Guo
2011-08-19 7:17 ` Shawn Guo
2011-08-20 18:16 ` Rob Herring
2011-08-19 8:56 ` Dave Martin
2011-08-19 13:45 ` Arnd Bergmann [this message]
2011-08-20 14:48 ` Shawn Guo
2011-08-20 18:21 ` Rob Herring
2011-08-20 15:54 ` Shawn Guo
2011-08-20 16:10 ` Shawn Guo
2011-08-20 18:22 ` Rob Herring
2011-08-22 5:55 ` Shawn Guo
2011-08-22 10:01 ` Jamie Iles
2011-08-23 3:33 ` Shawn Guo
2011-08-22 8:35 ` Shawn Guo
2011-08-22 9:15 ` Shawn Guo
2011-08-22 13:23 ` Rob Herring
2011-08-16 20:34 ` [PATCH 3/6] MAINTAINERS: add Calxeda Highbank ARM platform Rob Herring
2011-08-16 20:34 ` [PATCH 4/6] ARM: highbank: add SMP support Rob Herring
2011-08-17 7:37 ` Russell King - ARM Linux
2011-08-17 14:01 ` Rob Herring
2011-08-17 18:52 ` Russell King - ARM Linux
2011-08-16 20:34 ` [PATCH 5/6] ARM: highbank: Add cpu hotplug support Rob Herring
2011-08-16 20:34 ` [PATCH 6/6] ARM: highbank: add suspend support Rob Herring
2011-08-25 1:17 ` Shawn Guo
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