From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Zhao Subject: Re: [PATCH V2 1/4] cpufreq: add arm soc generic cpufreq driver Date: Mon, 19 Dec 2011 09:03:58 +0800 Message-ID: <20111219010357.GW28768@b20223-02.ap.freescale.net> References: <1324031462-24961-1-git-send-email-richard.zhao@linaro.org> <1324031462-24961-2-git-send-email-richard.zhao@linaro.org> <20111216105229.GB3230@totoro> <4EEBA306.3060309@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <4EEBA306.3060309@codeaurora.org> Sender: cpufreq-owner@vger.kernel.org To: Bryan Huntsman Cc: Jamie Iles , linux@arm.linux.org.uk, patches@linaro.org, linux-arm-msm@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, eric.miao@linaro.org, cpufreq@vger.kernel.org, kernel@pengutronix.de, davej@redhat.com, linaro-dev@lists.linaro.org, Richard Zhao , linux-arm-kernel@lists.infradead.org List-Id: linux-arm-msm@vger.kernel.org Hi Bryan, On Fri, Dec 16, 2011 at 11:59:02AM -0800, Bryan Huntsman wrote: > On 12/16/2011 02:52 AM, Jamie Iles wrote: > > > >> +static DEFINE_PER_CPU(unsigned long, l_p_j_ref); > >> +static unsigned long l_p_j_ref_freq; > >> + > >> +static struct clk *cpu_clk; > > > > This assumes that all CPU's share the same clk and run at the same rate. > > Is that a fair/safe assumption? I honestly don't know the answer to > > this so it's just a question!!! > > On MSM, cpus independently scale both frequency and voltage. Our clock > driver isn't upstream yet. David Brown has a preliminary version here: > > https://www.codeaurora.org/gitweb/quic/kernel/?p=davidb/linux-msm.git;a=shortlog;h=refs/heads/msm-clock-rfc > > Once we get our driver upstream, MSM will be an exception and not select > ARM_GENERIC_CPUFREQ. We'll probably have a separate msm-cpufreq.c > driver under drivers/cpufreq/. Do you have to patch to implement per-cpu udelay? In current code, udelay uses global loops_per_jiffy. Thanks Richard > > - Bryan > > -- > Sent by an employee of the Qualcomm Innovation Center, Inc. > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > From mboxrd@z Thu Jan 1 00:00:00 1970 From: richard.zhao@freescale.com (Richard Zhao) Date: Mon, 19 Dec 2011 09:03:58 +0800 Subject: [PATCH V2 1/4] cpufreq: add arm soc generic cpufreq driver In-Reply-To: <4EEBA306.3060309@codeaurora.org> References: <1324031462-24961-1-git-send-email-richard.zhao@linaro.org> <1324031462-24961-2-git-send-email-richard.zhao@linaro.org> <20111216105229.GB3230@totoro> <4EEBA306.3060309@codeaurora.org> Message-ID: <20111219010357.GW28768@b20223-02.ap.freescale.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Bryan, On Fri, Dec 16, 2011 at 11:59:02AM -0800, Bryan Huntsman wrote: > On 12/16/2011 02:52 AM, Jamie Iles wrote: > > > >> +static DEFINE_PER_CPU(unsigned long, l_p_j_ref); > >> +static unsigned long l_p_j_ref_freq; > >> + > >> +static struct clk *cpu_clk; > > > > This assumes that all CPU's share the same clk and run at the same rate. > > Is that a fair/safe assumption? I honestly don't know the answer to > > this so it's just a question!!! > > On MSM, cpus independently scale both frequency and voltage. Our clock > driver isn't upstream yet. David Brown has a preliminary version here: > > https://www.codeaurora.org/gitweb/quic/kernel/?p=davidb/linux-msm.git;a=shortlog;h=refs/heads/msm-clock-rfc > > Once we get our driver upstream, MSM will be an exception and not select > ARM_GENERIC_CPUFREQ. We'll probably have a separate msm-cpufreq.c > driver under drivers/cpufreq/. Do you have to patch to implement per-cpu udelay? In current code, udelay uses global loops_per_jiffy. Thanks Richard > > - Bryan > > -- > Sent by an employee of the Qualcomm Innovation Center, Inc. > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >