From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752161AbaH1PLc (ORCPT ); Thu, 28 Aug 2014 11:11:32 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:37332 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750986AbaH1PLa (ORCPT ); Thu, 28 Aug 2014 11:11:30 -0400 Date: Thu, 28 Aug 2014 16:11:21 +0100 From: Mark Rutland To: Kever Yang Cc: "heiko@sntech.de" , "dianders@chromium.org" , "sonnyrao@chromium.org" , "addy.ke@rock-chips.com" , "cf@rock-chips.com" , "xjq@rock-chips.com" , "wulf@rock-chips.com" , "lyz@rock-chips.com" , "hj@rock-chips.com" , "huangtao@rock-chips.com" , Rob Herring , Pawel Moll , Ian Campbell , Kumar Gala , Russell King , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , lorenzo.pieralisi@arm.com Subject: Re: [RESEND PATCH] ARM: dts: make arch-timer always on in rk3288 soc Message-ID: <20140828151121.GM14650@leverpostej> References: <1409190017-12656-1-git-send-email-kever.yang@rock-chips.com> <20140828091758.GB14650@leverpostej> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140828091758.GB14650@leverpostej> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 28, 2014 at 10:17:58AM +0100, Mark Rutland wrote: > Hi Kever, > > On Thu, Aug 28, 2014 at 02:40:17AM +0100, Kever Yang wrote: > > We need use the hrtimer, which need the arch-timer to be 'always-on' > > I asked a question on the last posting [1]. Can you please confirm > either way? > > Thanks, > Mark. > > [1] lists.infradead.org/pipermail/linux-arm-kernel/2014-August/282327.html To clarify: if there are low power states that the CPU can enter where we lose state, then this patch isn't correct. A more general approach would be to enable the broadcast hrtimer for arm, as has been done for arm64. See commit 5d1638acb9f6 (tick: Introduce hrtimer based broadcast) which introduced the broadcast hrtimer, and commit 9358d755bd5c (arm64: kernel: initialize broadcast hrtimer based clock event device) which added the requisite plumbing for arm64. Mark. > > > Signed-off-by: Kever Yang > > --- > > > > arch/arm/boot/dts/rk3288.dtsi | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi > > index 5950b0a..698e6ea 100644 > > --- a/arch/arm/boot/dts/rk3288.dtsi > > +++ b/arch/arm/boot/dts/rk3288.dtsi > > @@ -76,6 +76,7 @@ > > , > > ; > > clock-frequency = <24000000>; > > + always-on; > > }; > > > > i2c1: i2c@ff140000 { > > -- > > 1.9.1 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe devicetree" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > -- > To unsubscribe from this list: send the line "unsubscribe devicetree" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >