From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from db8outboundpool.messaging.microsoft.com (mail-db8lp0187.outbound.messaging.microsoft.com [213.199.154.187]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "MSIT Machine Auth CA 2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 579AB2C0097 for ; Fri, 23 Aug 2013 07:25:02 +1000 (EST) Message-ID: <1377206679.20722.10.camel@snotra.buserror.net> Subject: Re: [RFC PATCH V3 3/5] powerpc/cpuidle: Generic powerpc backend cpuidle driver. From: Scott Wood To: Deepthi Dharwar Date: Thu, 22 Aug 2013 16:24:39 -0500 In-Reply-To: <5215A69F.4090904@linux.vnet.ibm.com> References: <20130819042736.8609.17890.stgit@deepthi.in.ibm.com> <20130819042818.8609.77060.stgit@deepthi.in.ibm.com> <5211F0E0.7080507@linux.vnet.ibm.com> <1376936241.31636.352.camel@snotra.buserror.net> <521447E7.5000302@linux.vnet.ibm.com> <1377115703.5029.14.camel@snotra.buserror.net> <5215A69F.4090904@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: Wood Scott-B07421 , Wang Dongsheng-B40534 , "daniel.lezcano@linaro.org" , "preeti@linux.vnet.ibm.com" , "linux-pm@lists.linux-foundation.org" , "linuxppc-dev@lists.ozlabs.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2013-08-22 at 11:20 +0530, Deepthi Dharwar wrote: > On 08/22/2013 01:38 AM, Scott Wood wrote: > > On Wed, 2013-08-21 at 10:23 +0530, Deepthi Dharwar wrote: > >> On 08/19/2013 11:47 PM, Scott Wood wrote: > >>> What actual functionality is common to all powerpc but not common to > >>> other arches? > > > > The functionality here is idle states on powerpc like the snooze loop > that is common. > Also, the basic registration of the driver, hotplug notifier etc for > powerpc. The snooze loop uses things like SPRN_PURR, get_lppaca(), and CTRL which aren't common to all PPC (they might be common to all book3s64). I also don't see any hook for the low power mode entry -- is "snooze" just a busy loop plus the de-emphasis stuff like HMT and CTRL[RUN]? I'm not familiar with the term "snooze" in this context. I don't think we'd use anything like that on our chips; we'd always at least "wait" or "doze" depending on the chip. It's not clear what is powerpc-specific about the notifier -- perhaps it should go in drivers/cpuidle/. > > The way forward is to give this file a more appropriate name based on > > the hardware that it actually targets -- and to refactor it so that the > > answer to that question is not complicated. > > Sure, thanks. > Our idea was to have POWER archs idle states merged at the first go. > Only that is what is enabled in the current version (V4 posted out) > ( Code is enabled for PSERIES and POWERNV only) > If needed, other POWERPC archs might benefit by extending the same > driver, that is why it is named cpuidle-powerpc.c > > But if having cpuidle backend-driver separately for other powerpc arcs > makes sense such that each one have their own state information etc > then it makes sense to name the files as cpuidle-power.c, > cpuilde-ppc32.c and so on. Thanks. -Scott