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From: Christopher Covington <cov@codeaurora.org>
To: Stephen Boyd <sboyd@codeaurora.org>
Cc: David Brown <davidb@codeaurora.org>,
	Kumar Gala <galak@codeaurora.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: dts: msm8974: Move arch-timer out of soc node
Date: Mon, 17 Mar 2014 13:31:23 -0400	[thread overview]
Message-ID: <5327316B.6040007@codeaurora.org> (raw)
In-Reply-To: <1394573058-18561-1-git-send-email-sboyd@codeaurora.org>

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.

Thanks,
Christopher

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

WARNING: multiple messages have this Message-ID (diff)
From: cov@codeaurora.org (Christopher Covington)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: dts: msm8974: Move arch-timer out of soc node
Date: Mon, 17 Mar 2014 13:31:23 -0400	[thread overview]
Message-ID: <5327316B.6040007@codeaurora.org> (raw)
In-Reply-To: <1394573058-18561-1-git-send-email-sboyd@codeaurora.org>

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.

Thanks,
Christopher

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

  reply	other threads:[~2014-03-17 17:31 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-11 21:24 [PATCH] ARM: dts: msm8974: Move arch-timer out of soc node Stephen Boyd
2014-03-11 21:24 ` Stephen Boyd
2014-03-17 17:31 ` Christopher Covington [this message]
2014-03-17 17:31   ` Christopher Covington
2014-03-17 17:33   ` Kumar Gala
2014-03-17 17:33     ` Kumar Gala
2014-03-17 17:48     ` Christopher Covington
2014-03-17 17:48       ` Christopher Covington

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