From: marc.zyngier@arm.com (Marc Zyngier)
Date: Tue, 21 Jun 2011 14:02:49 +0100
Subject: [RFC PATCH 00/16] Consolidation: move SMP local timers to
	driver/clocksource
In-Reply-To: <4E0093CF.6030804@gmail.com>
References: <1308251204-16719-1-git-send-email-marc.zyngier@arm.com>
	<201106171707.23989.arnd@arndb.de> <4DFB8E20.60802@gmail.com>
	<4E007CEB.6040104@arm.com> <4E0093CF.6030804@gmail.com>
Message-ID: <4E009679.4010206@arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 21/06/11 13:51, Rob Herring wrote:
> Marc,
> 
> On 06/21/2011 06:13 AM, Marc Zyngier wrote:
>> On 17/06/11 18:25, Rob Herring wrote:
>>> Also, device tree support for early platform devices would be useful for
>>> this.
>>
>> What about the attached patch? I've used it to boot a VExpress board
>> with the following DT snippet (and the corresponding support in the
>> amp_smp_twd driver):
>>
>> 	localtimer at 2c000600 {
>> 		device_type = "localtimer";
> 
> My understanding is device_type is only supposed to be used for devices
> with real OpenFirmware. You could just add localtimer or timer as a 2nd
> compatible string. I think localtimer is a bit of a Linux name, so just
> timer may be better.

Using "compatible" would not work. You'd have to add the same compatible
string to all drivers, and get drivers probing the wrong device. Any
other property we could use instead?

As for the "localtimer" string, this is to differentiate the per-cpu
timers versus the global timers, and they may need to be probed in a
specific order (global first, and then local).

The reason for this is that TWD needs to be calibrated, hence the need
for a global timer running. Colin's patch could help getting rid of this
restriction though.

	M.
-- 
Jazz is not dead. It just smells funny...