Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752941Ab1FMB5w (ORCPT ); Sun, 12 Jun 2011 21:57:52 -0400 Received: from mail-vx0-f174.google.com ([209.85.220.174]:53297 "EHLO mail-vx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752402Ab1FMB5r (ORCPT ); Sun, 12 Jun 2011 21:57:47 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=JCnviYIwMnpznfq7Y/nc5SZw7mpfCmS3XZ8r26aYmSyzL8A87OdY3DFZvoH66jJWof TnO1IXkxDMAW7/rhHaBfvWof3dW71tbPQ/MANI9o0YAgZy2f80u/DXRdnMGFrCaUhXhe suTY7pZPZSiNSrhIS2w0D64w6Ao4fkZNXRAls= Message-ID: <4DF56E97.1020907@gmail.com> Date: Sun, 12 Jun 2011 20:57:43 -0500 From: Rob Herring User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110516 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: Colin Cross CC: linux-arm-kernel@lists.infradead.org, Nicolas Pitre , Russell King , Peter Zijlstra , Catalin Marinas , linux-kernel@vger.kernel.org, Santosh Shilimkar , Eric Miao , Leif Lindholm Subject: Re: [PATCH 1/3] ARM: Add cpu power management notifiers References: <1307925825-28566-1-git-send-email-ccross@android.com> <1307925825-28566-2-git-send-email-ccross@android.com> In-Reply-To: <1307925825-28566-2-git-send-email-ccross@android.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9605 Lines: 304 On 06/12/2011 07:43 PM, Colin Cross wrote: > During some CPU power modes entered during idle, hotplug and > suspend, peripherals located in the CPU power domain, such as > the GIC and VFP, may be powered down. Add a notifier chain > that allows drivers for those peripherals to be notified > before and after they may be reset. > > Signed-off-by: Colin Cross > --- > arch/arm/Kconfig | 7 ++ > arch/arm/include/asm/cpu_pm.h | 54 ++++++++++++ > arch/arm/kernel/Makefile | 1 + > arch/arm/kernel/cpu_pm.c | 181 +++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 243 insertions(+), 0 deletions(-) > create mode 100644 arch/arm/include/asm/cpu_pm.h > create mode 100644 arch/arm/kernel/cpu_pm.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 9adc278..356f266 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -183,6 +183,13 @@ config FIQ > config ARCH_MTD_XIP > bool > > +config ARCH_USES_CPU_PM > + bool > + > +config CPU_PM > + def_bool y > + depends on ARCH_USES_CPU_PM&& (PM || CPU_IDLE) > + > config VECTORS_BASE > hex > default 0xffff0000 if MMU || CPU_HIGH_VECTOR > diff --git a/arch/arm/include/asm/cpu_pm.h b/arch/arm/include/asm/cpu_pm.h > new file mode 100644 > index 0000000..b4bb715 > --- /dev/null > +++ b/arch/arm/include/asm/cpu_pm.h > @@ -0,0 +1,54 @@ > +/* > + * Copyright (C) 2011 Google, Inc. > + * > + * Author: > + * Colin Cross > + * > + * This software is licensed under the terms of the GNU General Public > + * License version 2, as published by the Free Software Foundation, and > + * may be copied, distributed, and modified under those terms. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#ifndef _ASMARM_CPU_PM_H > +#define _ASMARM_CPU_PM_H > + > +#include > +#include > + > +/* Event codes passed as unsigned long val to notifier calls */ > +enum cpu_pm_event { > + /* A single cpu is entering a low power state */ > + CPU_PM_ENTER, > + > + /* A single cpu failed to enter a low power state */ > + CPU_PM_ENTER_FAILED, > + > + /* A single cpu is exiting a low power state */ > + CPU_PM_EXIT, > + > + /* A cpu power domain is entering a low power state */ > + CPU_COMPLEX_PM_ENTER, > + > + /* A cpu power domain failed to enter a low power state */ > + CPU_COMPLEX_PM_ENTER_FAILED, > + > + /* A cpu power domain is exiting a low power state */ > + CPU_COMPLEX_PM_EXIT, > +}; > + > +int cpu_pm_register_notifier(struct notifier_block *nb); > +int cpu_pm_unregister_notifier(struct notifier_block *nb); > + > +int cpu_pm_enter(void); > +int cpu_pm_exit(void); > + > +int cpu_complex_pm_enter(void); > +int cpu_complex_pm_exit(void); > + > +#endif > diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile > index a5b31af..8b42d58 100644 > --- a/arch/arm/kernel/Makefile > +++ b/arch/arm/kernel/Makefile > @@ -60,6 +60,7 @@ obj-$(CONFIG_CPU_PJ4) += pj4-cp0.o > obj-$(CONFIG_IWMMXT) += iwmmxt.o > obj-$(CONFIG_CPU_HAS_PMU) += pmu.o > obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o > +obj-$(CONFIG_CPU_PM) += cpu_pm.o > AFLAGS_iwmmxt.o := -Wa,-mcpu=iwmmxt > > ifneq ($(CONFIG_ARCH_EBSA110),y) > diff --git a/arch/arm/kernel/cpu_pm.c b/arch/arm/kernel/cpu_pm.c > new file mode 100644 > index 0000000..48a5b53 > --- /dev/null > +++ b/arch/arm/kernel/cpu_pm.c > @@ -0,0 +1,181 @@ > +/* > + * Copyright (C) 2011 Google, Inc. > + * > + * Author: > + * Colin Cross > + * > + * This software is licensed under the terms of the GNU General Public > + * License version 2, as published by the Free Software Foundation, and > + * may be copied, distributed, and modified under those terms. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#include > +#include > +#include > +#include > + > +#include > + > +/* > + * When a CPU goes to a low power state that turns off power to the CPU's > + * power domain, the contents of some blocks (floating point coprocessors, > + * interrutp controllers, caches, timers) in the same power domain can > + * be lost. The cpm_pm notifiers provide a method for platform idle, suspend, > + * and hotplug implementations to notify the drivers for these blocks that > + * they may be reset. > + * > + * All cpu_pm notifications must be called with interrupts disabled. > + * > + * The notifications are split into two classes, CPU notifications and CPU > + * complex notifications. > + * > + * CPU notifications apply to a single CPU, and must be called on the affected > + * CPU. They are used to save per-cpu context for affected blocks. > + * > + * CPU complex notifications apply to all CPUs in a single power domain. They > + * are used to save any global context for affected blocks, and must be called > + * after all the CPUs in the power domain have been notified of the low power > + * state. > + * > + */ > + > +static DEFINE_RWLOCK(cpu_pm_notifier_lock); > +static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain); > + > +int cpu_pm_register_notifier(struct notifier_block *nb) > +{ > + unsigned long flags; > + int ret; > + > + write_lock_irqsave(&cpu_pm_notifier_lock, flags); > + ret = raw_notifier_chain_register(&cpu_pm_notifier_chain, nb); > + write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); > + > +int cpu_pm_unregister_notifier(struct notifier_block *nb) > +{ > + unsigned long flags; > + int ret; > + > + write_lock_irqsave(&cpu_pm_notifier_lock, flags); > + ret = raw_notifier_chain_unregister(&cpu_pm_notifier_chain, nb); > + write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); > + > +static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) > +{ > + int ret; > + > + ret = __raw_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, > + nr_to_call, nr_calls); > + > + return notifier_to_errno(ret); > +} > + > +/** > + * cpm_pm_enter > + * > + * Notifies listeners that a single cpu is entering a low power state that may > + * cause some blocks in the same power domain as the cpu to reset. > + * > + * Must be called on the affected cpu with interrupts disabled. Platform is > + * responsible for ensuring that cpu_pm_enter is not called twice on the same > + * cpu before cpu_pm_exit is called. > + */ > +int cpu_pm_enter(void) > +{ > + int nr_calls; > + int ret = 0; > + > + read_lock(&cpu_pm_notifier_lock); > + ret = cpu_pm_notify(CPU_PM_ENTER, -1,&nr_calls); > + if (ret) > + cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL); > + read_unlock(&cpu_pm_notifier_lock); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(cpu_pm_enter); > + > +/** > + * cpm_pm_exit > + * > + * Notifies listeners that a single cpu is exiting a low power state that may > + * have caused some blocks in the same power domain as the cpu to reset. > + * > + * Must be called on the affected cpu with interrupts disabled. > + */ > +int cpu_pm_exit(void) > +{ > + int ret; > + > + read_lock(&cpu_pm_notifier_lock); > + ret = cpu_pm_notify(CPU_PM_EXIT, -1, NULL); > + read_unlock(&cpu_pm_notifier_lock); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(cpu_pm_exit); > + > +/** > + * cpm_complex_pm_enter > + * > + * Notifies listeners that all cpus in a power domain are entering a low power > + * state that may cause some blocks in the same power domain to reset. > + * > + * Must be called after cpu_pm_enter has been called on all cpus in the power > + * domain, and before cpu_pm_exit has been called on any cpu in the power > + * domain. > + * > + * Must be called with interrupts disabled. > + */ > +int cpu_complex_pm_enter(void) > +{ > + int nr_calls; > + int ret = 0; > + > + read_lock(&cpu_pm_notifier_lock); > + ret = cpu_pm_notify(CPU_COMPLEX_PM_ENTER, -1,&nr_calls); > + if (ret) > + cpu_pm_notify(CPU_COMPLEX_PM_ENTER_FAILED, nr_calls - 1, NULL); > + read_unlock(&cpu_pm_notifier_lock); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(cpu_complex_pm_enter); > + > +/** > + * cpm_pm_enter > + * > + * Notifies listeners that a single cpu is entering a low power state that may > + * cause some blocks in the same power domain as the cpu to reset. > + * > + * Must be called after cpu_pm_enter has been called on all cpus in the power > + * domain, and before cpu_pm_exit has been called on any cpu in the power > + * domain. > + * > + * Must be called with interrupts disabled. > + */ > +int cpu_complex_pm_exit(void) > +{ > + int ret; > + > + read_lock(&cpu_pm_notifier_lock); > + ret = cpu_pm_notify(CPU_COMPLEX_PM_EXIT, -1, NULL); > + read_unlock(&cpu_pm_notifier_lock); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(cpu_complex_pm_exit); Nothing really ARM specific here, so why not make this generic for all architectures? Rob -- 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/