From d6f346f2d2bf511c2c59176121a6e42ce60173a0 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Tue, 28 May 2013 15:51:54 +0000 Subject: cpuidle: improve governor Kconfig options Each governor is suitable for different kernel configurations: the menu governor suits better for a tickless system, while the ladder governor fits better for a periodic timer tick system. The Kconfig does not allow to [un]select a governor, thus both are compiled in the kernel but the init order makes the menu governor to be the last one to be registered, so becoming the default. The only way to switch back to the ladder governor is to enable the sysfs governor switch in the kernel command line. Because it seems nobody complained about this, the menu governor is used by default most of the time on the system, having both governors is not really necessary on a tickless system but there isn't a config option to disable one or another governor. Create a submenu for cpuidle and add a label for each governor, so we can see the option in the menu config and enable/disable it. The governors will be enabled depending on the CONFIG_NO_HZ option: - If CONFIG_NO_HZ is set, then the menu governor is selected and the ladder governor is optional, defaulting to 'yes' - If CONFIG_NO_HZ is not set, then the ladder governor is selected and the menu governor is optional, defaulting to 'yes' Signed-off-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index c4cc27e..e997f15 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -1,7 +1,9 @@ -config CPU_IDLE +menuconfig CPU_IDLE bool "CPU idle PM support" default y if ACPI || PPC_PSERIES + select CPU_IDLE_GOV_LADDER if (!NO_HZ && !NO_HZ_IDLE) + select CPU_IDLE_GOV_MENU if (NO_HZ || NO_HZ_IDLE) help CPU idle is a generic framework for supporting software-controlled idle processor power management. It includes modular cross-platform @@ -9,9 +11,10 @@ config CPU_IDLE If you're using an ACPI-enabled platform, you should say Y here. +if CPU_IDLE + config CPU_IDLE_MULTIPLE_DRIVERS bool "Support multiple cpuidle drivers" - depends on CPU_IDLE default n help Allows the cpuidle framework to use different drivers for each CPU. @@ -19,24 +22,19 @@ config CPU_IDLE_MULTIPLE_DRIVERS states. If unsure say N. config CPU_IDLE_GOV_LADDER - bool - depends on CPU_IDLE + bool "Ladder governor (for periodic timer tick)" default y config CPU_IDLE_GOV_MENU - bool - depends on CPU_IDLE && NO_HZ + bool "Menu governor (for tickless system)" default y config ARCH_NEEDS_CPU_IDLE_COUPLED def_bool n -if CPU_IDLE - config CPU_IDLE_CALXEDA bool "CPU Idle Driver for Calxeda processors" depends on ARCH_HIGHBANK help Select this to enable cpuidle on Calxeda processors. - endif -- cgit v0.10.2 From bd2a337a25dd22bcd6b3fb1f99461f6991773e68 Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Tue, 4 Jun 2013 07:17:39 +0000 Subject: ARM: zynq: Add cpuidle support Add cpuidle support for Xilinx Zynq. Signed-off-by: Michal Simek Acked-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki diff --git a/MAINTAINERS b/MAINTAINERS index f35a259..796aa0f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1309,6 +1309,7 @@ W: http://wiki.xilinx.com T: git git://git.xilinx.com/linux-xlnx.git S: Supported F: arch/arm/mach-zynq/ +F: drivers/cpuidle/cpuidle-zynq.c ARM64 PORT (AARCH64 ARCHITECTURE) M: Catalin Marinas diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index e997f15..a7d2e83 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -37,4 +37,11 @@ config CPU_IDLE_CALXEDA depends on ARCH_HIGHBANK help Select this to enable cpuidle on Calxeda processors. + +config CPU_IDLE_ZYNQ + bool "CPU Idle Driver for Xilinx Zynq processors" + depends on ARCH_ZYNQ + help + Select this to enable cpuidle on Xilinx Zynq processors. + endif diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index 0d8bd55..8767a7b 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -7,3 +7,4 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o +obj-$(CONFIG_CPU_IDLE_ZYNQ) += cpuidle-zynq.o diff --git a/drivers/cpuidle/cpuidle-zynq.c b/drivers/cpuidle/cpuidle-zynq.c new file mode 100644 index 0000000..38e03a1 --- /dev/null +++ b/drivers/cpuidle/cpuidle-zynq.c @@ -0,0 +1,83 @@ +/* + * Copyright (C) 2012-2013 Xilinx + * + * CPU idle support for Xilinx Zynq + * + * based on arch/arm/mach-at91/cpuidle.c + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see . + * + * The cpu idle uses wait-for-interrupt and RAM self refresh in order + * to implement two idle states - + * #1 wait-for-interrupt + * #2 wait-for-interrupt and RAM self refresh + * + * Maintainer: Michal Simek + */ + +#include +#include +#include +#include +#include +#include + +#define ZYNQ_MAX_STATES 2 + +/* Actual code that puts the SoC in different idle states */ +static int zynq_enter_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) +{ + /* Devices must be stopped here */ + cpu_pm_enter(); + + /* Add code for DDR self refresh start */ + cpu_do_idle(); + + /* Add code for DDR self refresh stop */ + cpu_pm_exit(); + + return index; +} + +static struct cpuidle_driver zynq_idle_driver = { + .name = "zynq_idle", + .owner = THIS_MODULE, + .states = { + ARM_CPUIDLE_WFI_STATE, + { + .enter = zynq_enter_idle, + .exit_latency = 10, + .target_residency = 10000, + .flags = CPUIDLE_FLAG_TIME_VALID | + CPUIDLE_FLAG_TIMER_STOP, + .name = "RAM_SR", + .desc = "WFI and RAM Self Refresh", + }, + }, + .safe_state_index = 0, + .state_count = ZYNQ_MAX_STATES, +}; + +/* Initialize CPU idle by registering the idle states */ +static int __init zynq_cpuidle_init(void) +{ + if (!of_machine_is_compatible("xlnx,zynq-7000")) + return -ENODEV; + + pr_info("Xilinx Zynq CpuIdle Driver started\n"); + + return cpuidle_register(&zynq_idle_driver, NULL); +} + +device_initcall(zynq_cpuidle_init); -- cgit v0.10.2 From 82467a5a885ddd9f80309682159da8db510e7832 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Fri, 7 Jun 2013 21:53:09 +0000 Subject: cpuidle: simplify multiple driver support Commit bf4d1b5 (cpuidle: support multiple drivers) introduced support for using multiple cpuidle drivers at the same time. It added a couple of new APIs to register the driver per CPU, but that led to some unnecessary code complexity related to the kernel config options deciding whether or not the multiple driver support is enabled. The code has to work as it did before when the multiple driver support is not enabled and the multiple driver support has to be compatible with the previously existing API. Remove the new API, not used by any driver in the tree yet (but needed for the HMP cpuidle drivers that will be submitted soon), and add a new cpumask pointer to the cpuidle driver structure that will point to the mask of CPUs handled by the given driver. That will allow the cpuidle_[un]register_driver() API to be used for the multiple driver support along with the cpuidle_[un]register() functions added recently. [rjw: Changelog] Signed-off-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index c3a93fe..fdc432f 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -466,7 +466,7 @@ void cpuidle_unregister(struct cpuidle_driver *drv) int cpu; struct cpuidle_device *device; - for_each_possible_cpu(cpu) { + for_each_cpu(cpu, drv->cpumask) { device = &per_cpu(cpuidle_dev, cpu); cpuidle_unregister_device(device); } @@ -498,7 +498,7 @@ int cpuidle_register(struct cpuidle_driver *drv, return ret; } - for_each_possible_cpu(cpu) { + for_each_cpu(cpu, drv->cpumask) { device = &per_cpu(cpuidle_dev, cpu); device->cpu = cpu; diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index 8dfaaae..e75fa54 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -18,167 +18,140 @@ DEFINE_SPINLOCK(cpuidle_driver_lock); -static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu); -static struct cpuidle_driver * __cpuidle_get_cpu_driver(int cpu); +#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS -static void cpuidle_setup_broadcast_timer(void *arg) +static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers); + +static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) { - int cpu = smp_processor_id(); - clockevents_notify((long)(arg), &cpu); + return per_cpu(cpuidle_drivers, cpu); } -static void __cpuidle_driver_init(struct cpuidle_driver *drv, int cpu) +static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) { - int i; - - drv->refcnt = 0; + int cpu; - for (i = drv->state_count - 1; i >= 0 ; i--) { + for_each_cpu(cpu, drv->cpumask) { - if (!(drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP)) + if (drv != __cpuidle_get_cpu_driver(cpu)) continue; - drv->bctimer = 1; - on_each_cpu_mask(get_cpu_mask(cpu), cpuidle_setup_broadcast_timer, - (void *)CLOCK_EVT_NOTIFY_BROADCAST_ON, 1); - break; + per_cpu(cpuidle_drivers, cpu) = NULL; } } -static int __cpuidle_register_driver(struct cpuidle_driver *drv, int cpu) +static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) { - if (!drv || !drv->state_count) - return -EINVAL; - - if (cpuidle_disabled()) - return -ENODEV; + int cpu; - if (__cpuidle_get_cpu_driver(cpu)) - return -EBUSY; + for_each_cpu(cpu, drv->cpumask) { - __cpuidle_driver_init(drv, cpu); + if (__cpuidle_get_cpu_driver(cpu)) { + __cpuidle_unset_driver(drv); + return -EBUSY; + } - __cpuidle_set_cpu_driver(drv, cpu); + per_cpu(cpuidle_drivers, cpu) = drv; + } return 0; } -static void __cpuidle_unregister_driver(struct cpuidle_driver *drv, int cpu) -{ - if (drv != __cpuidle_get_cpu_driver(cpu)) - return; +#else - if (!WARN_ON(drv->refcnt > 0)) - __cpuidle_set_cpu_driver(NULL, cpu); +static struct cpuidle_driver *cpuidle_curr_driver; - if (drv->bctimer) { - drv->bctimer = 0; - on_each_cpu_mask(get_cpu_mask(cpu), cpuidle_setup_broadcast_timer, - (void *)CLOCK_EVT_NOTIFY_BROADCAST_OFF, 1); - } +static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) +{ + return cpuidle_curr_driver; } -#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS +static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) +{ + if (cpuidle_curr_driver) + return -EBUSY; -static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers); + cpuidle_curr_driver = drv; -static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu) -{ - per_cpu(cpuidle_drivers, cpu) = drv; + return 0; } -static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) +static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) { - return per_cpu(cpuidle_drivers, cpu); + if (drv == cpuidle_curr_driver) + cpuidle_curr_driver = NULL; } -static void __cpuidle_unregister_all_cpu_driver(struct cpuidle_driver *drv) +#endif + +static void cpuidle_setup_broadcast_timer(void *arg) { - int cpu; - for_each_present_cpu(cpu) - __cpuidle_unregister_driver(drv, cpu); + int cpu = smp_processor_id(); + clockevents_notify((long)(arg), &cpu); } -static int __cpuidle_register_all_cpu_driver(struct cpuidle_driver *drv) +static int __cpuidle_driver_init(struct cpuidle_driver *drv) { - int ret = 0; - int i, cpu; + int i; - for_each_present_cpu(cpu) { - ret = __cpuidle_register_driver(drv, cpu); - if (ret) - break; - } + drv->refcnt = 0; - if (ret) - for_each_present_cpu(i) { - if (i == cpu) - break; - __cpuidle_unregister_driver(drv, i); - } + if (!drv->cpumask) + drv->cpumask = (struct cpumask *)cpu_possible_mask; + for (i = drv->state_count - 1; i >= 0 ; i--) { - return ret; + if (!(drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP)) + continue; + + drv->bctimer = 1; + break; + } + + return 0; } -int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu) +static int __cpuidle_register_driver(struct cpuidle_driver *drv) { int ret; - spin_lock(&cpuidle_driver_lock); - ret = __cpuidle_register_driver(drv, cpu); - spin_unlock(&cpuidle_driver_lock); + if (!drv || !drv->state_count) + return -EINVAL; - return ret; -} + if (cpuidle_disabled()) + return -ENODEV; -void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu) -{ - spin_lock(&cpuidle_driver_lock); - __cpuidle_unregister_driver(drv, cpu); - spin_unlock(&cpuidle_driver_lock); -} + ret = __cpuidle_driver_init(drv); + if (ret) + return ret; -/** - * cpuidle_register_driver - registers a driver - * @drv: the driver - */ -int cpuidle_register_driver(struct cpuidle_driver *drv) -{ - int ret; + ret = __cpuidle_set_driver(drv); + if (ret) + return ret; - spin_lock(&cpuidle_driver_lock); - ret = __cpuidle_register_all_cpu_driver(drv); - spin_unlock(&cpuidle_driver_lock); + if (drv->bctimer) + on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, + (void *)CLOCK_EVT_NOTIFY_BROADCAST_ON, 1); - return ret; + return 0; } -EXPORT_SYMBOL_GPL(cpuidle_register_driver); /** * cpuidle_unregister_driver - unregisters a driver * @drv: the driver */ -void cpuidle_unregister_driver(struct cpuidle_driver *drv) +static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) { - spin_lock(&cpuidle_driver_lock); - __cpuidle_unregister_all_cpu_driver(drv); - spin_unlock(&cpuidle_driver_lock); -} -EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); - -#else - -static struct cpuidle_driver *cpuidle_curr_driver; + if (WARN_ON(drv->refcnt > 0)) + return; -static inline void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu) -{ - cpuidle_curr_driver = drv; -} + if (drv->bctimer) { + drv->bctimer = 0; + on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, + (void *)CLOCK_EVT_NOTIFY_BROADCAST_OFF, 1); + } -static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) -{ - return cpuidle_curr_driver; + __cpuidle_unset_driver(drv); } /** @@ -187,13 +160,11 @@ static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) */ int cpuidle_register_driver(struct cpuidle_driver *drv) { - int ret, cpu; + int ret; - cpu = get_cpu(); spin_lock(&cpuidle_driver_lock); - ret = __cpuidle_register_driver(drv, cpu); + ret = __cpuidle_register_driver(drv); spin_unlock(&cpuidle_driver_lock); - put_cpu(); return ret; } @@ -205,16 +176,11 @@ EXPORT_SYMBOL_GPL(cpuidle_register_driver); */ void cpuidle_unregister_driver(struct cpuidle_driver *drv) { - int cpu; - - cpu = get_cpu(); spin_lock(&cpuidle_driver_lock); - __cpuidle_unregister_driver(drv, cpu); + __cpuidle_unregister_driver(drv); spin_unlock(&cpuidle_driver_lock); - put_cpu(); } EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); -#endif /** * cpuidle_get_driver - return the current driver diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 8f04062..0bc4b74 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -111,6 +111,9 @@ struct cpuidle_driver { struct cpuidle_state states[CPUIDLE_STATE_MAX]; int state_count; int safe_state_index; + + /* the driver handles the cpus in cpumask */ + struct cpumask *cpumask; }; #ifdef CONFIG_CPU_IDLE @@ -135,9 +138,6 @@ extern void cpuidle_disable_device(struct cpuidle_device *dev); extern int cpuidle_play_dead(void); extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev); -extern int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu); -extern void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu); - #else static inline void disable_cpuidle(void) { } static inline int cpuidle_idle_call(void) { return -ENODEV; } -- cgit v0.10.2 From 6d19cb93d60a5403753756c502699751116c954c Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Fri, 7 Jun 2013 21:53:10 +0000 Subject: cpuidle: Comment the driver's framework code Add kerneldoc (and other) comments to the cpuidle driver's framework code. Signed-off-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index e75fa54..3ac499d 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -22,11 +22,26 @@ DEFINE_SPINLOCK(cpuidle_driver_lock); static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers); +/** + * __cpuidle_get_cpu_driver - return the cpuidle driver tied to a CPU. + * @cpu: the CPU handled by the driver + * + * Returns a pointer to struct cpuidle_driver or NULL if no driver has been + * registered for @cpu. + */ static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) { return per_cpu(cpuidle_drivers, cpu); } +/** + * __cpuidle_unset_driver - unset per CPU driver variables. + * @drv: a valid pointer to a struct cpuidle_driver + * + * For each CPU in the driver's CPU mask, unset the registered driver per CPU + * variable. If @drv is different from the registered driver, the corresponding + * variable is not cleared. + */ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) { int cpu; @@ -40,6 +55,15 @@ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) } } +/** + * __cpuidle_set_driver - set per CPU driver variables the the given driver. + * @drv: a valid pointer to a struct cpuidle_driver + * + * For each CPU in the driver's cpumask, unset the registered driver per CPU + * to @drv. + * + * Returns 0 on success, -EBUSY if the CPUs have driver(s) already. + */ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) { int cpu; @@ -61,11 +85,24 @@ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) static struct cpuidle_driver *cpuidle_curr_driver; +/** + * __cpuidle_get_cpu_driver - return the global cpuidle driver pointer. + * @cpu: ignored without the multiple driver support + * + * Return a pointer to a struct cpuidle_driver object or NULL if no driver was + * previously registered. + */ static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) { return cpuidle_curr_driver; } +/** + * __cpuidle_set_driver - assign the global cpuidle driver variable. + * @drv: pointer to a struct cpuidle_driver object + * + * Returns 0 on success, -EBUSY if the driver is already registered. + */ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) { if (cpuidle_curr_driver) @@ -76,6 +113,13 @@ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) return 0; } +/** + * __cpuidle_unset_driver - unset the global cpuidle driver variable. + * @drv: a pointer to a struct cpuidle_driver + * + * Reset the global cpuidle variable to NULL. If @drv does not match the + * registered driver, do nothing. + */ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) { if (drv == cpuidle_curr_driver) @@ -84,21 +128,49 @@ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) #endif +/** + * cpuidle_setup_broadcast_timer - enable/disable the broadcast timer + * @arg: a void pointer used to match the SMP cross call API + * + * @arg is used as a value of type 'long' with on of the two values: + * - CLOCK_EVT_NOTIFY_BROADCAST_ON + * - CLOCK_EVT_NOTIFY_BROADCAST_OFF + * + * Set the broadcast timer notification for the current CPU. This function + * is executed per CPU by an SMP cross call. It not supposed to be called + * directly. + */ static void cpuidle_setup_broadcast_timer(void *arg) { int cpu = smp_processor_id(); clockevents_notify((long)(arg), &cpu); } +/** + * __cpuidle_driver_init - initialize the driver's internal data + * @drv: a valid pointer to a struct cpuidle_driver + * + * Returns 0 on success, a negative error code otherwise. + */ static int __cpuidle_driver_init(struct cpuidle_driver *drv) { int i; drv->refcnt = 0; + /* + * Use all possible CPUs as the default, because if the kernel boots + * with some CPUs offline and then we online one of them, the CPU + * notifier has to know which driver to assign. + */ if (!drv->cpumask) drv->cpumask = (struct cpumask *)cpu_possible_mask; + /* + * Look for the timer stop flag in the different states, so that we know + * if the broadcast timer has to be set up. The loop is in the reverse + * order, because usually on of the the deeper states has this flag set. + */ for (i = drv->state_count - 1; i >= 0 ; i--) { if (!(drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP)) @@ -111,6 +183,19 @@ static int __cpuidle_driver_init(struct cpuidle_driver *drv) return 0; } +/** + * __cpuidle_register_driver: register the driver + * @drv: a valid pointer to a struct cpuidle_driver + * + * Do some sanity checks, initialize the driver, assign the driver to the + * global cpuidle driver variable(s) and set up the broadcast timer if the + * cpuidle driver has some states that shut down the local timer. + * + * Returns 0 on success, a negative error code otherwise: + * * -EINVAL if the driver pointer is NULL or no idle states are available + * * -ENODEV if the cpuidle framework is disabled + * * -EBUSY if the driver is already assigned to the global variable(s) + */ static int __cpuidle_register_driver(struct cpuidle_driver *drv) { int ret; @@ -137,8 +222,13 @@ static int __cpuidle_register_driver(struct cpuidle_driver *drv) } /** - * cpuidle_unregister_driver - unregisters a driver - * @drv: the driver + * __cpuidle_unregister_driver - unregister the driver + * @drv: a valid pointer to a struct cpuidle_driver + * + * Check if the driver is no longer in use, reset the global cpuidle driver + * variable(s) and disable the timer broadcast notification mechanism if it was + * in use. + * */ static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) { @@ -156,7 +246,13 @@ static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) /** * cpuidle_register_driver - registers a driver - * @drv: the driver + * @drv: a pointer to a valid struct cpuidle_driver + * + * Register the driver under a lock to prevent concurrent attempts to + * [un]register the driver from occuring at the same time. + * + * Returns 0 on success, a negative error code (returned by + * __cpuidle_register_driver()) otherwise. */ int cpuidle_register_driver(struct cpuidle_driver *drv) { @@ -172,7 +268,11 @@ EXPORT_SYMBOL_GPL(cpuidle_register_driver); /** * cpuidle_unregister_driver - unregisters a driver - * @drv: the driver + * @drv: a pointer to a valid struct cpuidle_driver + * + * Unregisters the cpuidle driver under a lock to prevent concurrent attempts + * to [un]register the driver from occuring at the same time. @drv has to + * match the currently registered driver. */ void cpuidle_unregister_driver(struct cpuidle_driver *drv) { @@ -183,7 +283,9 @@ void cpuidle_unregister_driver(struct cpuidle_driver *drv) EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); /** - * cpuidle_get_driver - return the current driver + * cpuidle_get_driver - return the driver tied to the current CPU. + * + * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered. */ struct cpuidle_driver *cpuidle_get_driver(void) { @@ -199,7 +301,11 @@ struct cpuidle_driver *cpuidle_get_driver(void) EXPORT_SYMBOL_GPL(cpuidle_get_driver); /** - * cpuidle_get_cpu_driver - return the driver tied with a cpu + * cpuidle_get_cpu_driver - return the driver registered for a CPU. + * @dev: a valid pointer to a struct cpuidle_device + * + * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered + * for the CPU associated with @dev. */ struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev) { @@ -210,6 +316,14 @@ struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev) } EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver); +/** + * cpuidle_driver_ref - get a reference to the driver. + * + * Increment the reference counter of the cpuidle driver associated with + * the current CPU. + * + * Returns a pointer to the driver, or NULL if the current CPU has no driver. + */ struct cpuidle_driver *cpuidle_driver_ref(void) { struct cpuidle_driver *drv; @@ -223,6 +337,12 @@ struct cpuidle_driver *cpuidle_driver_ref(void) return drv; } +/** + * cpuidle_driver_unref - puts down the refcount for the driver + * + * Decrement the reference counter of the cpuidle driver associated with + * the current CPU. + */ void cpuidle_driver_unref(void) { struct cpuidle_driver *drv = cpuidle_get_driver(); -- cgit v0.10.2 From b39b0981b0811943d724915a8a0150d6ac5110e0 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Tue, 11 Jun 2013 08:09:45 +0000 Subject: cpuidle: Fix ARCH_NEEDS_CPU_IDLE_COUPLED dependency warning Before commit d6f346f (cpuidle: improve governor Kconfig options), the CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED option didn't depend on CONFIG_CPU_IDLE but now it has been moved under the CPU_IDLE menuconfig. That raises the following warnings: warning: (ARCH_OMAP4 && ARCH_TEGRA_2x_SOC) selects ARCH_NEEDS_CPU_IDLE_COUPLED which has unmet direct dependencies (CPU_IDLE) warning: (ARCH_OMAP4 && ARCH_TEGRA_2x_SOC) selects ARCH_NEEDS_CPU_IDLE_COUPLED which has unmet direct dependencies (CPU_IDLE) because the tegra2 and omap4 Kconfig files select this option without checking if CPU_IDLE is set. Fix that by moving ARCH_NEEDS_CPU_IDLE_COUPLED outside of CPU_IDLE. [rjw: Changelog] Signed-off-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index a7d2e83..81de5d9 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -29,9 +29,6 @@ config CPU_IDLE_GOV_MENU bool "Menu governor (for tickless system)" default y -config ARCH_NEEDS_CPU_IDLE_COUPLED - def_bool n - config CPU_IDLE_CALXEDA bool "CPU Idle Driver for Calxeda processors" depends on ARCH_HIGHBANK @@ -45,3 +42,6 @@ config CPU_IDLE_ZYNQ Select this to enable cpuidle on Xilinx Zynq processors. endif + +config ARCH_NEEDS_CPU_IDLE_COUPLED + def_bool n -- cgit v0.10.2