From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f50.google.com (mail-ee0-f50.google.com [74.125.83.50]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (not verified)) by ozlabs.org (Postfix) with ESMTPS id DDFC52C0105 for ; Tue, 30 Jul 2013 00:44:51 +1000 (EST) Received: by mail-ee0-f50.google.com with SMTP id d51so1551075eek.9 for ; Mon, 29 Jul 2013 07:44:46 -0700 (PDT) Message-ID: <51F67FDE.6070902@linaro.org> Date: Mon, 29 Jul 2013 16:44:46 +0200 From: Daniel Lezcano MIME-Version: 1.0 To: Deepthi Dharwar Subject: Re: [PATCH 2/3] cpuidle/powernv: Enable idle powernv cpu to call into the cpuidle framework. References: <20130723090111.7291.99479.stgit@deepthi.in.ibm.com> <20130723090150.7291.89879.stgit@deepthi.in.ibm.com> <51F35AC7.8060909@linaro.org> <51F67BE5.10701@linux.vnet.ibm.com> In-Reply-To: <51F67BE5.10701@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Cc: linux-pm@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 07/29/2013 04:27 PM, Deepthi Dharwar wrote: > On 07/27/2013 10:59 AM, Daniel Lezcano wrote: >> On 07/23/2013 11:01 AM, Deepthi Dharwar wrote: >>> This patch enables idle powernv cpu to hook on to the cpuidle >>> framework, if available, else call on to default idle platform >>> code. >> >> Why do you need to do that ? >> > > Hi Daniel, > > Well, this is needed in case when one does not compile with CPU_IDLE > config option. > > When CPUIDLE is not configured, idle cpus are needed to be running some > sort of default idle code or loop ( in the worst case) if cpuidle driver > is not registered or if one decides not to have that config enabled. Hi Deepthi, ok may be there is some difference with the other platform but the arch_cpu_idle function defined in the other archs do: void arch_cpu_idle(void) { if (cpuidle_idle_call()) x86_idle(); else local_irq_enable(); } or void arch_cpu_idle(void) { if (cpuidle_idle_call()) default_idle(); } When the cpuidle driver is not compiled or not loaded, cpuidle_idle_call fails, falling back to the default idle function. The arch_cpu_idle function is called from the generic code in kernel/cpu/idle.c. Is there a particular reason to do it in a different way ? Thanks -- Daniel >> >>> Signed-off-by: Deepthi Dharwar >>> --- >>> arch/powerpc/platforms/powernv/setup.c | 12 +++++++++++- >>> 1 file changed, 11 insertions(+), 1 deletion(-) >>> >>> diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c >>> index 84438af..97d0951 100644 >>> --- a/arch/powerpc/platforms/powernv/setup.c >>> +++ b/arch/powerpc/platforms/powernv/setup.c >>> @@ -25,6 +25,7 @@ >>> #include >>> #include >>> #include >>> +#include >>> >>> #include >>> #include >>> @@ -196,6 +197,15 @@ static int __init pnv_probe(void) >>> return 1; >>> } >>> >>> +void powernv_idle(void) >>> +{ >>> + /* Hook to cpuidle framework if available, else >>> + * call on default platform idle code >>> + */ >>> + if (cpuidle_idle_call()) >>> + power7_idle(); >>> +} >>> + >>> define_machine(powernv) { >>> .name = "PowerNV", >>> .probe = pnv_probe, >>> @@ -205,7 +215,7 @@ define_machine(powernv) { >>> .show_cpuinfo = pnv_show_cpuinfo, >>> .progress = pnv_progress, >>> .machine_shutdown = pnv_shutdown, >>> - .power_save = power7_idle, >>> + .power_save = powernv_idle, >>> .calibrate_decr = generic_calibrate_decr, >>> #ifdef CONFIG_KEXEC >>> .kexec_cpu_down = pnv_kexec_cpu_down, >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> Please read the FAQ at http://www.tux.org/lkml/ >>> >> >> > -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog