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 454a26205787..4ea5a75fcacd 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 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 7066acb2c530..033b507b33b1 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 a520fd70a59f..5088727478fd 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 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 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 include/linux/alarmtimer.h (limited to 'include/linux') diff --git a/include/linux/alarmtimer.h b/include/linux/alarmtimer.h new file mode 100644 index 000000000000..6b364b2e2074 --- /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 -- cgit v1.2.3 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 ++ 3 files changed, 10 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/capability.h b/include/linux/capability.h index 16ee8b49a200..7cb23eae693d 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 d51243ae0726..808227d40a64 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 4ea5a75fcacd..b3061782dec3 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: -- cgit v1.2.3 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 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/alarmtimer.h b/include/linux/alarmtimer.h index 6b364b2e2074..c5d6095b46f8 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; }; -- cgit v1.2.3