From ab10023e0088d5075354afc7cb9e72304757dddd Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Thu, 10 Feb 2011 02:04:45 -0800 Subject: cpu_pm: Add cpu power management notifiers During some CPU power modes entered during idle, hotplug and suspend, peripherals located in the CPU power domain, such as the GIC, localtimers, 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. Notified drivers can include VFP co-processor, interrupt controller and it's PM extensions, local CPU timers context save/restore which shouldn't be interrupted. Hence CPU PM event APIs must be called with interrupts disabled. Signed-off-by: Colin Cross Signed-off-by: Santosh Shilimkar Reviewed-by: Kevin Hilman Tested-and-Acked-by: Shawn Guo Tested-by: Kevin Hilman Tested-by: Vishwanath BS --- kernel/cpu_pm.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 kernel/cpu_pm.c (limited to 'kernel/cpu_pm.c') diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c new file mode 100644 index 00000000000..4d1ff4acd04 --- /dev/null +++ b/kernel/cpu_pm.c @@ -0,0 +1,200 @@ +/* + * 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 + +static DEFINE_RWLOCK(cpu_pm_notifier_lock); +static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain); + +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); +} + +/** + * cpu_pm_register_notifier - register a driver with cpu_pm + * @nb: notifier block to register + * + * Add a driver to a list of drivers that are notified about + * CPU and CPU cluster low power entry and exit. + * + * This function may sleep, and has the same return conditions as + * raw_notifier_chain_register. + */ +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); + +/** + * cpu_pm_unregister_notifier - unregister a driver with cpu_pm + * @nb: notifier block to be unregistered + * + * Remove a driver from the CPU PM notifier list. + * + * This function may sleep, and has the same return conditions as + * raw_notifier_chain_unregister. + */ +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); + +/** + * cpm_pm_enter - CPU low power entry notifier + * + * 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. Notified drivers can include VFP + * co-processor, interrupt controller and it's PM extensions, local CPU + * timers context save/restore which shouldn't be interrupted. Hence it + * must be called with interrupts disabled. + * + * Return conditions are same as __raw_notifier_call_chain. + */ +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) + /* + * Inform listeners (nr_calls - 1) about failure of CPU PM + * PM entry who are notified earlier to prepare for it. + */ + 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 - CPU low power exit notifier + * + * 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. + * + * Notified drivers can include VFP co-processor, interrupt controller + * and it's PM extensions, local CPU timers context save/restore which + * shouldn't be interrupted. Hence it must be called with interrupts disabled. + * + * Return conditions are same as __raw_notifier_call_chain. + */ +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_cluster_pm_enter - CPU cluster low power entry notifier + * + * 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. Notified drivers can include VFP co-processor, interrupt controller + * and it's PM extensions, local CPU timers context save/restore which + * shouldn't be interrupted. Hence it must be called with interrupts disabled. + * + * Must be called with interrupts disabled. + * + * Return conditions are same as __raw_notifier_call_chain. + */ +int cpu_cluster_pm_enter(void) +{ + int nr_calls; + int ret = 0; + + read_lock(&cpu_pm_notifier_lock); + ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls); + if (ret) + /* + * Inform listeners (nr_calls - 1) about failure of CPU cluster + * PM entry who are notified earlier to prepare for it. + */ + cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL); + read_unlock(&cpu_pm_notifier_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); + +/** + * cpm_cluster_pm_exit - CPU cluster low power exit notifier + * + * Notifies listeners that all cpus in a power domain are exiting form a + * low power state that may have caused some blocks in the same power domain + * to reset. + * + * Must be called after cpu_pm_exit 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. Notified drivers can include VFP co-processor, interrupt controller + * and it's PM extensions, local CPU timers context save/restore which + * shouldn't be interrupted. Hence it must be called with interrupts disabled. + * + * Return conditions are same as __raw_notifier_call_chain. + */ +int cpu_cluster_pm_exit(void) +{ + int ret; + + read_lock(&cpu_pm_notifier_lock); + ret = cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); + read_unlock(&cpu_pm_notifier_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); -- cgit v1.2.3-70-g09d2 From 6f3eaec87b6b17bfa49cb3b5b8d07fa84be18512 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Fri, 22 Jul 2011 14:57:09 -0700 Subject: cpu_pm: call notifiers during suspend Implements syscore_ops in cpu_pm to call the cpu and cpu cluster notifiers during suspend and resume, allowing drivers receiving the notifications to avoid implementing syscore_ops. Signed-off-by: Colin Cross Signed-off-by: Santosh Shilimkar Reviewed-by: Kevin Hilman Tested-and-Acked-by: Shawn Guo Tested-by: Vishwanath BS --- kernel/cpu_pm.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'kernel/cpu_pm.c') diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c index 4d1ff4acd04..249152e1530 100644 --- a/kernel/cpu_pm.c +++ b/kernel/cpu_pm.c @@ -20,6 +20,7 @@ #include #include #include +#include static DEFINE_RWLOCK(cpu_pm_notifier_lock); static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain); @@ -198,3 +199,35 @@ int cpu_cluster_pm_exit(void) return ret; } EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); + +#ifdef CONFIG_PM +static int cpu_pm_suspend(void) +{ + int ret; + + ret = cpu_pm_enter(); + if (ret) + return ret; + + ret = cpu_cluster_pm_enter(); + return ret; +} + +static void cpu_pm_resume(void) +{ + cpu_cluster_pm_exit(); + cpu_pm_exit(); +} + +static struct syscore_ops cpu_pm_syscore_ops = { + .suspend = cpu_pm_suspend, + .resume = cpu_pm_resume, +}; + +static int cpu_pm_init(void) +{ + register_syscore_ops(&cpu_pm_syscore_ops); + return 0; +} +core_initcall(cpu_pm_init); +#endif -- cgit v1.2.3-70-g09d2