From 304529b1b6f8612ccbb4582e997051b48b94f4a4 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Fri, 1 Apr 2011 14:32:09 -0700 Subject: time: Add timekeeping_inject_sleeptime MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some platforms cannot implement read_persistent_clock, as their RTC devices are only accessible when interrupts are enabled. This keeps them from being used by the timekeeping code on resume to measure the time in suspend. The RTC layer tries to work around this, by calling do_settimeofday on resume after irqs are reenabled to set the time properly. However, this only corrects CLOCK_REALTIME, and does not properly adjust the sleep time value. This causes btime in /proc/stat to be incorrect as well as making the new CLOCK_BOTTTIME inaccurate. This patch resolves the issue by introducing a new timekeeping hook to allow the RTC layer to inject the sleep time on resume. The code also checks to make sure that read_persistent_clock is nonfunctional before setting the sleep time, so that should the RTC's HCTOSYS option be configured in on a system that does support read_persistent_clock we will not increase the total_sleep_time twice. CC: Arve Hjønnevåg CC: Thomas Gleixner Acked-by: Arnd Bergmann Signed-off-by: John Stultz --- include/linux/time.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/time.h b/include/linux/time.h index 454a2620578..4ea5a75fcac 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -126,6 +126,7 @@ struct timespec __current_kernel_time(void); /* does not take xtime_lock */ struct timespec get_monotonic_coarse(void); void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, struct timespec *wtom, struct timespec *sleep); +void timekeeping_inject_sleeptime(struct timespec *delta); #define CURRENT_TIME (current_kernel_time()) #define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 }) -- cgit v1.2.3-70-g09d2 From 88d19cf37952a7e1e38b2bf87a00f0e857e63180 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 3 Jan 2011 18:59:43 -0800 Subject: timers: Add rb_init_node() to allow for stack allocated rb nodes In cases where a timerqueue_node or some structure that utilizes a timerqueue_node is allocated on the stack, gcc would give warnings caused by the timerqueue_init()'s calling RB_CLEAR_NODE, which self-references the nodes uninitialized data. The solution is to create an rb_init_node() function that zeros the rb_node structure out and then calls RB_CLEAR_NODE(), and then call the new init function from timerqueue_init(). CC: Thomas Gleixner Acked-by: Arnd Bergmann Signed-off-by: John Stultz --- include/linux/rbtree.h | 8 ++++++++ include/linux/timerqueue.h | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h index 7066acb2c53..033b507b33b 100644 --- a/include/linux/rbtree.h +++ b/include/linux/rbtree.h @@ -136,6 +136,14 @@ static inline void rb_set_color(struct rb_node *rb, int color) #define RB_EMPTY_NODE(node) (rb_parent(node) == node) #define RB_CLEAR_NODE(node) (rb_set_parent(node, node)) +static inline void rb_init_node(struct rb_node *rb) +{ + rb->rb_parent_color = 0; + rb->rb_right = NULL; + rb->rb_left = NULL; + RB_CLEAR_NODE(rb); +} + extern void rb_insert_color(struct rb_node *, struct rb_root *); extern void rb_erase(struct rb_node *, struct rb_root *); diff --git a/include/linux/timerqueue.h b/include/linux/timerqueue.h index a520fd70a59..5088727478f 100644 --- a/include/linux/timerqueue.h +++ b/include/linux/timerqueue.h @@ -39,7 +39,7 @@ struct timerqueue_node *timerqueue_getnext(struct timerqueue_head *head) static inline void timerqueue_init(struct timerqueue_node *node) { - RB_CLEAR_NODE(&node->node); + rb_init_node(&node->node); } static inline void timerqueue_init_head(struct timerqueue_head *head) -- cgit v1.2.3-70-g09d2 From ff3ead96d17f47ee70c294a5cc2cce9b61e82f0f Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 11 Jan 2011 09:42:13 -0800 Subject: timers: Introduce in-kernel alarm-timer interface MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This provides the in kernel interface and infrastructure for alarm-timers. Alarm-timers are a hybrid style timer, similar to hrtimers, but when the system is suspended, the RTC device is set to fire and wake the system for when the soonest alarm-timer expires. The concept for Alarm-timers was inspired by the Android Alarm driver (by Arve Hjønnevåg) found in the Android kernel tree. See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36 This in-kernel interface should be fairly compatible with the Android alarm driver in-kernel interface, but has the advantage of utilizing the new RTC timerqueue code instead of doing direct RTC manipulation. CC: Arve Hjønnevåg CC: Thomas Gleixner CC: Alessandro Zummo Acked-by: Arnd Bergmann Signed-off-by: John Stultz --- include/linux/alarmtimer.h | 30 ++++ kernel/time/Makefile | 2 +- kernel/time/alarmtimer.c | 375 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 406 insertions(+), 1 deletion(-) create mode 100644 include/linux/alarmtimer.h create mode 100644 kernel/time/alarmtimer.c (limited to 'include/linux') diff --git a/include/linux/alarmtimer.h b/include/linux/alarmtimer.h new file mode 100644 index 00000000000..6b364b2e207 --- /dev/null +++ b/include/linux/alarmtimer.h @@ -0,0 +1,30 @@ +#ifndef _LINUX_ALARMTIMER_H +#define _LINUX_ALARMTIMER_H + +#include +#include +#include +#include + +enum alarmtimer_type { + ALARM_REALTIME, + ALARM_BOOTTIME, + + ALARM_NUMTYPE, +}; + +struct alarm { + struct timerqueue_node node; + ktime_t period; + void (*function)(struct alarm *); + enum alarmtimer_type type; + char enabled; + void *data; +}; + +void alarm_init(struct alarm *alarm, enum alarmtimer_type type, + void (*function)(struct alarm *)); +void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period); +void alarm_cancel(struct alarm *alarm); + +#endif diff --git a/kernel/time/Makefile b/kernel/time/Makefile index b0425991e9a..e2fd74b8e8c 100644 --- a/kernel/time/Makefile +++ b/kernel/time/Makefile @@ -1,5 +1,5 @@ obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o -obj-y += timeconv.o posix-clock.o +obj-y += timeconv.o posix-clock.o alarmtimer.o obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD) += clockevents.o obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c new file mode 100644 index 00000000000..48c2ee949e6 --- /dev/null +++ b/kernel/time/alarmtimer.c @@ -0,0 +1,375 @@ +/* + * Alarmtimer interface + * + * This interface provides a timer which is similarto hrtimers, + * but triggers a RTC alarm if the box is suspend. + * + * This interface is influenced by the Android RTC Alarm timer + * interface. + * + * Copyright (C) 2010 IBM Corperation + * + * Author: John Stultz + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +static struct alarm_base { + spinlock_t lock; + struct timerqueue_head timerqueue; + struct hrtimer timer; + ktime_t (*gettime)(void); + clockid_t base_clockid; + struct work_struct irqwork; +} alarm_bases[ALARM_NUMTYPE]; + +static struct rtc_timer rtctimer; +static struct rtc_device *rtcdev; + +static ktime_t freezer_delta; +static DEFINE_SPINLOCK(freezer_delta_lock); + + +/************************************************************************** + * alarmtimer management code + */ + +/* + * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue + * @base: pointer to the base where the timer is being run + * @alarm: pointer to alarm being enqueued. + * + * Adds alarm to a alarm_base timerqueue and if necessary sets + * an hrtimer to run. + * + * Must hold base->lock when calling. + */ +static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) +{ + timerqueue_add(&base->timerqueue, &alarm->node); + if (&alarm->node == timerqueue_getnext(&base->timerqueue)) { + hrtimer_try_to_cancel(&base->timer); + hrtimer_start(&base->timer, alarm->node.expires, + HRTIMER_MODE_ABS); + } +} + +/* + * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue + * @base: pointer to the base where the timer is running + * @alarm: pointer to alarm being removed + * + * Removes alarm to a alarm_base timerqueue and if necessary sets + * a new timer to run. + * + * Must hold base->lock when calling. + */ +static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) +{ + struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue); + + timerqueue_del(&base->timerqueue, &alarm->node); + if (next == &alarm->node) { + hrtimer_try_to_cancel(&base->timer); + next = timerqueue_getnext(&base->timerqueue); + if (!next) + return; + hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS); + } +} + +/* + * alarmtimer_do_work - Handles alarm being fired. + * @work: pointer to workqueue being run + * + * When a timer fires, this runs through the timerqueue to see + * which alarm timers, and run those that expired. If there are + * more alarm timers queued, we set the hrtimer to fire in the + * future. + */ +void alarmtimer_do_work(struct work_struct *work) +{ + struct alarm_base *base = container_of(work, struct alarm_base, + irqwork); + struct timerqueue_node *next; + unsigned long flags; + ktime_t now; + + spin_lock_irqsave(&base->lock, flags); + now = base->gettime(); + while ((next = timerqueue_getnext(&base->timerqueue))) { + struct alarm *alarm; + ktime_t expired = next->expires; + + if (expired.tv64 >= now.tv64) + break; + + alarm = container_of(next, struct alarm, node); + + timerqueue_del(&base->timerqueue, &alarm->node); + alarm->enabled = 0; + /* Re-add periodic timers */ + if (alarm->period.tv64) { + alarm->node.expires = ktime_add(expired, alarm->period); + timerqueue_add(&base->timerqueue, &alarm->node); + alarm->enabled = 1; + } + spin_unlock_irqrestore(&base->lock, flags); + if (alarm->function) + alarm->function(alarm); + spin_lock_irqsave(&base->lock, flags); + } + + if (next) { + hrtimer_start(&base->timer, next->expires, + HRTIMER_MODE_ABS); + } + spin_unlock_irqrestore(&base->lock, flags); +} + + +/* + * alarmtimer_fired - Handles alarm hrtimer being fired. + * @timer: pointer to hrtimer being run + * + * When a timer fires, this schedules the do_work function to + * be run. + */ +static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) +{ + struct alarm_base *base = container_of(timer, struct alarm_base, timer); + schedule_work(&base->irqwork); + return HRTIMER_NORESTART; +} + + +/* + * alarmtimer_suspend - Suspend time callback + * @dev: unused + * @state: unused + * + * When we are going into suspend, we look through the bases + * to see which is the soonest timer to expire. We then + * set an rtc timer to fire that far into the future, which + * will wake us from suspend. + */ +static int alarmtimer_suspend(struct device *dev) +{ + struct rtc_time tm; + ktime_t min, now; + unsigned long flags; + int i; + + spin_lock_irqsave(&freezer_delta_lock, flags); + min = freezer_delta; + freezer_delta = ktime_set(0, 0); + spin_unlock_irqrestore(&freezer_delta_lock, flags); + + /* If we have no rtcdev, just return */ + if (!rtcdev) + return 0; + + /* Find the soonest timer to expire*/ + for (i = 0; i < ALARM_NUMTYPE; i++) { + struct alarm_base *base = &alarm_bases[i]; + struct timerqueue_node *next; + ktime_t delta; + + spin_lock_irqsave(&base->lock, flags); + next = timerqueue_getnext(&base->timerqueue); + spin_unlock_irqrestore(&base->lock, flags); + if (!next) + continue; + delta = ktime_sub(next->expires, base->gettime()); + if (!min.tv64 || (delta.tv64 < min.tv64)) + min = delta; + } + if (min.tv64 == 0) + return 0; + + /* XXX - Should we enforce a minimum sleep time? */ + WARN_ON(min.tv64 < NSEC_PER_SEC); + + /* Setup an rtc timer to fire that far in the future */ + rtc_timer_cancel(rtcdev, &rtctimer); + rtc_read_time(rtcdev, &tm); + now = rtc_tm_to_ktime(tm); + now = ktime_add(now, min); + + rtc_timer_start(rtcdev, &rtctimer, now, ktime_set(0, 0)); + + return 0; +} + + +/************************************************************************** + * alarm kernel interface code + */ + +/* + * alarm_init - Initialize an alarm structure + * @alarm: ptr to alarm to be initialized + * @type: the type of the alarm + * @function: callback that is run when the alarm fires + * + * In-kernel interface to initializes the alarm structure. + */ +void alarm_init(struct alarm *alarm, enum alarmtimer_type type, + void (*function)(struct alarm *)) +{ + timerqueue_init(&alarm->node); + alarm->period = ktime_set(0, 0); + alarm->function = function; + alarm->type = type; + alarm->enabled = 0; +} + +/* + * alarm_start - Sets an alarm to fire + * @alarm: ptr to alarm to set + * @start: time to run the alarm + * @period: period at which the alarm will recur + * + * In-kernel interface set an alarm timer. + */ +void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + unsigned long flags; + + spin_lock_irqsave(&base->lock, flags); + if (alarm->enabled) + alarmtimer_remove(base, alarm); + alarm->node.expires = start; + alarm->period = period; + alarmtimer_enqueue(base, alarm); + alarm->enabled = 1; + spin_unlock_irqrestore(&base->lock, flags); +} + +/* + * alarm_cancel - Tries to cancel an alarm timer + * @alarm: ptr to alarm to be canceled + * + * In-kernel interface to cancel an alarm timer. + */ +void alarm_cancel(struct alarm *alarm) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + unsigned long flags; + + spin_lock_irqsave(&base->lock, flags); + if (alarm->enabled) + alarmtimer_remove(base, alarm); + alarm->enabled = 0; + spin_unlock_irqrestore(&base->lock, flags); +} + + + +/************************************************************************** + * alarmtimer initialization code + */ + +/* Suspend hook structures */ +static const struct dev_pm_ops alarmtimer_pm_ops = { + .suspend = alarmtimer_suspend, +}; + +static struct platform_driver alarmtimer_driver = { + .driver = { + .name = "alarmtimer", + .pm = &alarmtimer_pm_ops, + } +}; + +/** + * alarmtimer_init - Initialize alarm timer code + * + * This function initializes the alarm bases and registers + * the posix clock ids. + */ +static int __init alarmtimer_init(void) +{ + int error = 0; + int i; + + /* Initialize alarm bases */ + alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME; + alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real; + alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME; + alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime; + for (i = 0; i < ALARM_NUMTYPE; i++) { + timerqueue_init_head(&alarm_bases[i].timerqueue); + spin_lock_init(&alarm_bases[i].lock); + hrtimer_init(&alarm_bases[i].timer, + alarm_bases[i].base_clockid, + HRTIMER_MODE_ABS); + alarm_bases[i].timer.function = alarmtimer_fired; + INIT_WORK(&alarm_bases[i].irqwork, alarmtimer_do_work); + } + error = platform_driver_register(&alarmtimer_driver); + platform_device_register_simple("alarmtimer", -1, NULL, 0); + + return error; +} +device_initcall(alarmtimer_init); + +/** + * has_wakealarm - check rtc device has wakealarm ability + * @dev: current device + * @name_ptr: name to be returned + * + * This helper function checks to see if the rtc device can wake + * from suspend. + */ +static int __init has_wakealarm(struct device *dev, void *name_ptr) +{ + struct rtc_device *candidate = to_rtc_device(dev); + + if (!candidate->ops->set_alarm) + return 0; + if (!device_may_wakeup(candidate->dev.parent)) + return 0; + + *(const char **)name_ptr = dev_name(dev); + return 1; +} + +/** + * alarmtimer_init_late - Late initializing of alarmtimer code + * + * This function locates a rtc device to use for wakealarms. + * Run as late_initcall to make sure rtc devices have been + * registered. + */ +static int __init alarmtimer_init_late(void) +{ + char *str; + + /* Find an rtc device and init the rtc_timer */ + class_find_device(rtc_class, NULL, &str, has_wakealarm); + if (str) + rtcdev = rtc_class_open(str); + if (!rtcdev) { + printk(KERN_WARNING "No RTC device found, ALARM timers will" + " not wake from suspend"); + } + rtc_timer_init(&rtctimer, NULL, NULL); + + return 0; +} +late_initcall(alarmtimer_init_late); -- cgit v1.2.3-70-g09d2 From 9a7adcf5c6dea63d2e47e6f6d2f7a6c9f48b9337 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 11 Jan 2011 09:54:33 -0800 Subject: timers: Posix interface for alarm-timers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch exposes alarm-timers to userland via the posix clock and timers interface, using two new clockids: CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM. Both clockids behave identically to CLOCK_REALTIME and CLOCK_BOOTTIME, respectively, but timers set against the _ALARM suffixed clockids will wake the system if it is suspended. Some background can be found here: https://lwn.net/Articles/429925/ The concept for Alarm-timers was inspired by the Android Alarm driver (by Arve Hjønnevåg) found in the Android kernel tree. See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36 While the in-kernel interface is pretty similar between alarm-timers and Android alarm driver, the user-space interface for the Android alarm driver is via ioctls to a new char device. As mentioned above, I've instead chosen to export this functionality via the posix interface, as it seemed a little simpler and avoids creating duplicate interfaces to things like CLOCK_REALTIME and CLOCK_MONOTONIC under alternate names (ie:ANDROID_ALARM_RTC and ANDROID_ALARM_SYSTEMTIME). The semantics of the Android alarm driver are different from what this posix interface provides. For instance, threads other then the thread waiting on the Android alarm driver are able to modify the alarm being waited on. Also this interface does not allow the same wakelock semantics that the Android driver provides (ie: kernel takes a wakelock on RTC alarm-interupt, and holds it through process wakeup, and while the process runs, until the process either closes the char device or calls back in to wait on a new alarm). One potential way to implement similar semantics may be via the timerfd infrastructure, but this needs more research. There may also need to be some sort of sysfs system level policy hooks that allow alarm timers to be disabled to keep them from firing at inappropriate times (ie: laptop in a well insulated bag, mid-flight). CC: Arve Hjønnevåg CC: Thomas Gleixner CC: Alessandro Zummo Acked-by: Arnd Bergmann Signed-off-by: John Stultz --- include/linux/capability.h | 7 +- include/linux/posix-timers.h | 2 + include/linux/time.h | 2 + kernel/time/alarmtimer.c | 330 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 340 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/capability.h b/include/linux/capability.h index 16ee8b49a20..7cb23eae693 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -355,7 +355,12 @@ struct cpu_vfs_cap_data { #define CAP_SYSLOG 34 -#define CAP_LAST_CAP CAP_SYSLOG +/* Allow triggering something that will wake the system */ + +#define CAP_WAKE_ALARM 35 + + +#define CAP_LAST_CAP CAP_WAKE_ALARM #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP) diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index d51243ae072..808227d40a6 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -5,6 +5,7 @@ #include #include #include +#include union cpu_time_count { cputime_t cpu; @@ -80,6 +81,7 @@ struct k_itimer { unsigned long incr; unsigned long expires; } mmtimer; + struct alarm alarmtimer; } it; }; diff --git a/include/linux/time.h b/include/linux/time.h index 4ea5a75fcac..b3061782dec 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -295,6 +295,8 @@ struct itimerval { #define CLOCK_REALTIME_COARSE 5 #define CLOCK_MONOTONIC_COARSE 6 #define CLOCK_BOOTTIME 7 +#define CLOCK_REALTIME_ALARM 8 +#define CLOCK_BOOTTIME_ALARM 9 /* * The IDs of various hardware clocks: diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 48c2ee949e6..4058ad79d55 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -215,6 +215,21 @@ static int alarmtimer_suspend(struct device *dev) } +static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) +{ + ktime_t delta; + unsigned long flags; + struct alarm_base *base = &alarm_bases[type]; + + delta = ktime_sub(absexp, base->gettime()); + + spin_lock_irqsave(&freezer_delta_lock, flags); + if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64)) + freezer_delta = delta; + spin_unlock_irqrestore(&freezer_delta_lock, flags); +} + + /************************************************************************** * alarm kernel interface code */ @@ -279,6 +294,309 @@ void alarm_cancel(struct alarm *alarm) } +/************************************************************************** + * alarm posix interface code + */ + +/* + * clock2alarm - helper that converts from clockid to alarmtypes + * @clockid: clockid. + * + * Helper function that converts from clockids to alarmtypes + */ +static enum alarmtimer_type clock2alarm(clockid_t clockid) +{ + if (clockid == CLOCK_REALTIME_ALARM) + return ALARM_REALTIME; + if (clockid == CLOCK_BOOTTIME_ALARM) + return ALARM_BOOTTIME; + return -1; +} + +/* + * alarm_handle_timer - Callback for posix timers + * @alarm: alarm that fired + * + * Posix timer callback for expired alarm timers. + */ +static void alarm_handle_timer(struct alarm *alarm) +{ + struct k_itimer *ptr = container_of(alarm, struct k_itimer, + it.alarmtimer); + if (posix_timer_event(ptr, 0) != 0) + ptr->it_overrun++; +} + +/* + * alarm_clock_getres - posix getres interface + * @which_clock: clockid + * @tp: timespec to fill + * + * Returns the granularity of underlying alarm base clock + */ +static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp) +{ + clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid; + + return hrtimer_get_res(baseid, tp); +} + +/** + * alarm_clock_get - posix clock_get interface + * @which_clock: clockid + * @tp: timespec to fill. + * + * Provides the underlying alarm base time. + */ +static int alarm_clock_get(clockid_t which_clock, struct timespec *tp) +{ + struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)]; + + *tp = ktime_to_timespec(base->gettime()); + return 0; +} + +/** + * alarm_timer_create - posix timer_create interface + * @new_timer: k_itimer pointer to manage + * + * Initializes the k_itimer structure. + */ +static int alarm_timer_create(struct k_itimer *new_timer) +{ + enum alarmtimer_type type; + struct alarm_base *base; + + if (!capable(CAP_WAKE_ALARM)) + return -EPERM; + + type = clock2alarm(new_timer->it_clock); + base = &alarm_bases[type]; + alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer); + return 0; +} + +/** + * alarm_timer_get - posix timer_get interface + * @new_timer: k_itimer pointer + * @cur_setting: itimerspec data to fill + * + * Copies the itimerspec data out from the k_itimer + */ +static void alarm_timer_get(struct k_itimer *timr, + struct itimerspec *cur_setting) +{ + cur_setting->it_interval = + ktime_to_timespec(timr->it.alarmtimer.period); + cur_setting->it_value = + ktime_to_timespec(timr->it.alarmtimer.node.expires); + return; +} + +/** + * alarm_timer_del - posix timer_del interface + * @timr: k_itimer pointer to be deleted + * + * Cancels any programmed alarms for the given timer. + */ +static int alarm_timer_del(struct k_itimer *timr) +{ + alarm_cancel(&timr->it.alarmtimer); + return 0; +} + +/** + * alarm_timer_set - posix timer_set interface + * @timr: k_itimer pointer to be deleted + * @flags: timer flags + * @new_setting: itimerspec to be used + * @old_setting: itimerspec being replaced + * + * Sets the timer to new_setting, and starts the timer. + */ +static int alarm_timer_set(struct k_itimer *timr, int flags, + struct itimerspec *new_setting, + struct itimerspec *old_setting) +{ + /* Save old values */ + old_setting->it_interval = + ktime_to_timespec(timr->it.alarmtimer.period); + old_setting->it_value = + ktime_to_timespec(timr->it.alarmtimer.node.expires); + + /* If the timer was already set, cancel it */ + alarm_cancel(&timr->it.alarmtimer); + + /* start the timer */ + alarm_start(&timr->it.alarmtimer, + timespec_to_ktime(new_setting->it_value), + timespec_to_ktime(new_setting->it_interval)); + return 0; +} + +/** + * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep + * @alarm: ptr to alarm that fired + * + * Wakes up the task that set the alarmtimer + */ +static void alarmtimer_nsleep_wakeup(struct alarm *alarm) +{ + struct task_struct *task = (struct task_struct *)alarm->data; + + alarm->data = NULL; + if (task) + wake_up_process(task); +} + +/** + * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation + * @alarm: ptr to alarmtimer + * @absexp: absolute expiration time + * + * Sets the alarm timer and sleeps until it is fired or interrupted. + */ +static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp) +{ + alarm->data = (void *)current; + do { + set_current_state(TASK_INTERRUPTIBLE); + alarm_start(alarm, absexp, ktime_set(0, 0)); + if (likely(alarm->data)) + schedule(); + + alarm_cancel(alarm); + } while (alarm->data && !signal_pending(current)); + + __set_current_state(TASK_RUNNING); + + return (alarm->data == NULL); +} + + +/** + * update_rmtp - Update remaining timespec value + * @exp: expiration time + * @type: timer type + * @rmtp: user pointer to remaining timepsec value + * + * Helper function that fills in rmtp value with time between + * now and the exp value + */ +static int update_rmtp(ktime_t exp, enum alarmtimer_type type, + struct timespec __user *rmtp) +{ + struct timespec rmt; + ktime_t rem; + + rem = ktime_sub(exp, alarm_bases[type].gettime()); + + if (rem.tv64 <= 0) + return 0; + rmt = ktime_to_timespec(rem); + + if (copy_to_user(rmtp, &rmt, sizeof(*rmtp))) + return -EFAULT; + + return 1; + +} + +/** + * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep + * @restart: ptr to restart block + * + * Handles restarted clock_nanosleep calls + */ +static long __sched alarm_timer_nsleep_restart(struct restart_block *restart) +{ + enum alarmtimer_type type = restart->nanosleep.index; + ktime_t exp; + struct timespec __user *rmtp; + struct alarm alarm; + int ret = 0; + + exp.tv64 = restart->nanosleep.expires; + alarm_init(&alarm, type, alarmtimer_nsleep_wakeup); + + if (alarmtimer_do_nsleep(&alarm, exp)) + goto out; + + if (freezing(current)) + alarmtimer_freezerset(exp, type); + + rmtp = restart->nanosleep.rmtp; + if (rmtp) { + ret = update_rmtp(exp, type, rmtp); + if (ret <= 0) + goto out; + } + + + /* The other values in restart are already filled in */ + ret = -ERESTART_RESTARTBLOCK; +out: + return ret; +} + +/** + * alarm_timer_nsleep - alarmtimer nanosleep + * @which_clock: clockid + * @flags: determins abstime or relative + * @tsreq: requested sleep time (abs or rel) + * @rmtp: remaining sleep time saved + * + * Handles clock_nanosleep calls against _ALARM clockids + */ +static int alarm_timer_nsleep(const clockid_t which_clock, int flags, + struct timespec *tsreq, struct timespec __user *rmtp) +{ + enum alarmtimer_type type = clock2alarm(which_clock); + struct alarm alarm; + ktime_t exp; + int ret = 0; + struct restart_block *restart; + + if (!capable(CAP_WAKE_ALARM)) + return -EPERM; + + alarm_init(&alarm, type, alarmtimer_nsleep_wakeup); + + exp = timespec_to_ktime(*tsreq); + /* Convert (if necessary) to absolute time */ + if (flags != TIMER_ABSTIME) { + ktime_t now = alarm_bases[type].gettime(); + exp = ktime_add(now, exp); + } + + if (alarmtimer_do_nsleep(&alarm, exp)) + goto out; + + if (freezing(current)) + alarmtimer_freezerset(exp, type); + + /* abs timers don't set remaining time or restart */ + if (flags == TIMER_ABSTIME) { + ret = -ERESTARTNOHAND; + goto out; + } + + if (rmtp) { + ret = update_rmtp(exp, type, rmtp); + if (ret <= 0) + goto out; + } + + restart = ¤t_thread_info()->restart_block; + restart->fn = alarm_timer_nsleep_restart; + restart->nanosleep.index = type; + restart->nanosleep.expires = exp.tv64; + restart->nanosleep.rmtp = rmtp; + ret = -ERESTART_RESTARTBLOCK; + +out: + return ret; +} /************************************************************************** * alarmtimer initialization code @@ -306,6 +624,18 @@ static int __init alarmtimer_init(void) { int error = 0; int i; + struct k_clock alarm_clock = { + .clock_getres = alarm_clock_getres, + .clock_get = alarm_clock_get, + .timer_create = alarm_timer_create, + .timer_set = alarm_timer_set, + .timer_del = alarm_timer_del, + .timer_get = alarm_timer_get, + .nsleep = alarm_timer_nsleep, + }; + + posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock); + posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock); /* Initialize alarm bases */ alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME; -- cgit v1.2.3-70-g09d2 From 180bf812ceaf01eb8ac69b86f3be0bd57f697668 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 28 Apr 2011 12:58:11 -0700 Subject: timers: Improve alarmtimer comments and minor fixes This patch addresses a number of minor comment improvements and other minor issues from Thomas' review of the alarmtimers code. CC: Thomas Gleixner Signed-off-by: John Stultz --- include/linux/alarmtimer.h | 12 ++++++++- kernel/time/alarmtimer.c | 67 +++++++++++++++++++--------------------------- 2 files changed, 38 insertions(+), 41 deletions(-) (limited to 'include/linux') diff --git a/include/linux/alarmtimer.h b/include/linux/alarmtimer.h index 6b364b2e207..c5d6095b46f 100644 --- a/include/linux/alarmtimer.h +++ b/include/linux/alarmtimer.h @@ -13,12 +13,22 @@ enum alarmtimer_type { ALARM_NUMTYPE, }; +/** + * struct alarm - Alarm timer structure + * @node: timerqueue node for adding to the event list this value + * also includes the expiration time. + * @period: Period for recuring alarms + * @function: Function pointer to be executed when the timer fires. + * @type: Alarm type (BOOTTIME/REALTIME) + * @enabled: Flag that represents if the alarm is set to fire or not + * @data: Internal data value. + */ struct alarm { struct timerqueue_node node; ktime_t period; void (*function)(struct alarm *); enum alarmtimer_type type; - char enabled; + bool enabled; void *data; }; diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 4058ad79d55..bed98004ae1 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -26,7 +26,15 @@ #include #include - +/** + * struct alarm_base - Alarm timer bases + * @lock: Lock for syncrhonized access to the base + * @timerqueue: Timerqueue head managing the list of events + * @timer: hrtimer used to schedule events while running + * @gettime: Function to read the time correlating to the base + * @base_clockid: clockid for the base + * @irqwork Delayed work structure for expiring timers + */ static struct alarm_base { spinlock_t lock; struct timerqueue_head timerqueue; @@ -36,18 +44,16 @@ static struct alarm_base { struct work_struct irqwork; } alarm_bases[ALARM_NUMTYPE]; +/* rtc timer and device for setting alarm wakeups at suspend */ static struct rtc_timer rtctimer; static struct rtc_device *rtcdev; +/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */ static ktime_t freezer_delta; static DEFINE_SPINLOCK(freezer_delta_lock); -/************************************************************************** - * alarmtimer management code - */ - -/* +/** * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue * @base: pointer to the base where the timer is being run * @alarm: pointer to alarm being enqueued. @@ -67,7 +73,7 @@ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) } } -/* +/** * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue * @base: pointer to the base where the timer is running * @alarm: pointer to alarm being removed @@ -91,16 +97,16 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) } } -/* +/** * alarmtimer_do_work - Handles alarm being fired. * @work: pointer to workqueue being run * - * When a timer fires, this runs through the timerqueue to see - * which alarm timers, and run those that expired. If there are - * more alarm timers queued, we set the hrtimer to fire in the - * future. + * When a alarm timer fires, this runs through the timerqueue to + * see which alarms expired, and runs those. If there are more alarm + * timers queued for the future, we set the hrtimer to fire when + * when the next future alarm timer expires. */ -void alarmtimer_do_work(struct work_struct *work) +static void alarmtimer_do_work(struct work_struct *work) { struct alarm_base *base = container_of(work, struct alarm_base, irqwork); @@ -141,7 +147,7 @@ void alarmtimer_do_work(struct work_struct *work) } -/* +/** * alarmtimer_fired - Handles alarm hrtimer being fired. * @timer: pointer to hrtimer being run * @@ -156,7 +162,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) } -/* +/** * alarmtimer_suspend - Suspend time callback * @dev: unused * @state: unused @@ -230,17 +236,11 @@ static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) } -/************************************************************************** - * alarm kernel interface code - */ - -/* +/** * alarm_init - Initialize an alarm structure * @alarm: ptr to alarm to be initialized * @type: the type of the alarm * @function: callback that is run when the alarm fires - * - * In-kernel interface to initializes the alarm structure. */ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, void (*function)(struct alarm *)) @@ -252,13 +252,11 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, alarm->enabled = 0; } -/* +/** * alarm_start - Sets an alarm to fire * @alarm: ptr to alarm to set * @start: time to run the alarm * @period: period at which the alarm will recur - * - * In-kernel interface set an alarm timer. */ void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period) { @@ -275,11 +273,9 @@ void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period) spin_unlock_irqrestore(&base->lock, flags); } -/* +/** * alarm_cancel - Tries to cancel an alarm timer * @alarm: ptr to alarm to be canceled - * - * In-kernel interface to cancel an alarm timer. */ void alarm_cancel(struct alarm *alarm) { @@ -294,15 +290,9 @@ void alarm_cancel(struct alarm *alarm) } -/************************************************************************** - * alarm posix interface code - */ - -/* +/** * clock2alarm - helper that converts from clockid to alarmtypes * @clockid: clockid. - * - * Helper function that converts from clockids to alarmtypes */ static enum alarmtimer_type clock2alarm(clockid_t clockid) { @@ -313,7 +303,7 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid) return -1; } -/* +/** * alarm_handle_timer - Callback for posix timers * @alarm: alarm that fired * @@ -327,7 +317,7 @@ static void alarm_handle_timer(struct alarm *alarm) ptr->it_overrun++; } -/* +/** * alarm_clock_getres - posix getres interface * @which_clock: clockid * @tp: timespec to fill @@ -598,9 +588,6 @@ out: return ret; } -/************************************************************************** - * alarmtimer initialization code - */ /* Suspend hook structures */ static const struct dev_pm_ops alarmtimer_pm_ops = { -- cgit v1.2.3-70-g09d2