Re: [PATCH] ARM: dts: msm8974: Move arch-timer out of soc node

From: Kumar Gala
Date: Mon Mar 17 2014 - 13:34:02 EST



On Mar 17, 2014, at 12:31 PM, Christopher Covington <cov@xxxxxxxxxxxxxx> wrote:

> Hi Stephen,
>
> On 03/11/2014 05:24 PM, Stephen Boyd wrote:
>> The architected timer is not a register addressable piece of
>> hardware. Instead it's accessed through cp15 accessors. Move it
>> to the root of the devicetree to reflect this.
>
> I find this confusing, perhaps due to overloading of the word "register".
> Aren't CP15's a class of coprocessor _registers_? Could it perhaps be clearer
> to talk about memory-mapped versus CP15-mapped timers?
>
> Is "soc" documented somewhere or is it just a name for a container? Assuming
> the latter, it's not obvious to me why being a child of a system on chip node
> would imply having memory mapped registers.

“soc” is a container, since its compatible = "simple-bus”, this implies memory mapped register access for nodes inside of it.

- k
--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

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