26  * @brief  Kernel timer subsystem
27  * @defgroup timer Timers
29  * The timer subsystem allows functions to be scheduled for later
30  * execution.  Each timer object is used to cause one function to
33  * Timer callback functions are called in interrupt context.
42 #include <kernel/timer.h>
45 #include <platform/timer.h>
61  * @brief  Initialize a timer object
63 void timer_initialize(timer_t *timer)  in timer_initialize()  argument
65     *timer = (timer_t)TIMER_INITIAL_VALUE(*timer);  in timer_initialize()
68 static void insert_timer_in_queue(uint cpu, timer_t *timer)  in insert_timer_in_queue()  argument
74     LTRACEF("timer %p, cpu %u, scheduled %llu, periodic %llu\n", timer, cpu,  in insert_timer_in_queue()
75             timer->scheduled_time, timer->periodic_time);  in insert_timer_in_queue()
78         if (time_gt(entry->scheduled_time, timer->scheduled_time)) {  in insert_timer_in_queue()
79             list_add_before(&entry->node, &timer->node);  in insert_timer_in_queue()
85     list_add_tail(&timers[cpu].timer_queue, &timer->node);  in insert_timer_in_queue()
88 static void timer_set(timer_t *timer, lk_time_ns_t delay, lk_time_ns_t period,  in timer_set()  argument
93     LTRACEF("timer %p, delay %llu, period %llu, callback %p, arg %p\n", timer,  in timer_set()
96     DEBUG_ASSERT(timer->magic == TIMER_MAGIC);  in timer_set()
101     if (list_in_list(&timer->node)) {  in timer_set()
102         panic("timer %p already in list\n", timer);  in timer_set()
106     timer->scheduled_time = now + delay;  in timer_set()
107     timer->periodic_time = period;  in timer_set()
108     timer->callback = callback;  in timer_set()
109     timer->arg = arg;  in timer_set()
111     LTRACEF("scheduled time %llu\n", timer->scheduled_time);  in timer_set()
116      * It is not safe to move the timer to a new cpu while the callback is  in timer_set()
119     DEBUG_ASSERT(!timer->running || timer->cpu == cpu);  in timer_set()
122     timer->cpu = cpu;  in timer_set()
124     insert_timer_in_queue(cpu, timer);  in timer_set()
127     if (list_peek_head_type(&timers[cpu].timer_queue, timer_t, node) == timer) {  in timer_set()
128         /* we just modified the head of the timer queue */  in timer_set()
129         LTRACEF("setting new timer for %llu nanosecs\n", delay);  in timer_set()
130         platform_set_oneshot_timer(timer_tick, timer->scheduled_time);  in timer_set()
138  * @brief  Set up a timer that executes once
143  * @param  timer The timer to use
144  * @param  delay The delay, in ns, before the timer is executed
145  * @param  callback  The function to call when the timer expires
148  * The timer function is declared as:
149  *   enum handler_return callback(struct timer *, lk_time_t now, void *arg) { ... }
151 void timer_set_oneshot_ns(timer_t *timer, lk_time_ns_t delay,  in timer_set_oneshot_ns()  argument
156     timer_set(timer, delay, 0, callback, arg);  in timer_set_oneshot_ns()
160  * @brief  Set up a timer that executes repeatedly
165  * @param  timer The timer to use
166  * @param  period The delay, in ns, before the timer is executed
167  * @param  callback  The function to call when the timer expires
170  * The timer function is declared as:
171  *   enum handler_return callback(struct timer *, lk_time_t now, void *arg) { ... }
173 void timer_set_periodic_ns(timer_t *timer, lk_time_ns_t period,  in timer_set_periodic_ns()  argument
178     timer_set(timer, period, period, callback, arg);  in timer_set_periodic_ns()
182  * @brief  Cancel a pending timer
184 void timer_cancel_etc(timer_t *timer, bool wait)  in timer_cancel_etc()  argument
186     DEBUG_ASSERT(timer->magic == TIMER_MAGIC);  in timer_cancel_etc()
194      * be updated. We must wait before freeing the timer.  in timer_cancel_etc()
202      * It is safe to cancel the timer without waiting on the same cpu that the  in timer_cancel_etc()
205     DEBUG_ASSERT(wait || arch_curr_cpu_num() == timer->cpu);  in timer_cancel_etc()
207     while (wait && timer->running) {  in timer_cancel_etc()
220     if (list_in_list(&timer->node))  in timer_cancel_etc()
221         list_delete(&timer->node);  in timer_cancel_etc()
224      * periodic timer callback.  in timer_cancel_etc()
226     timer->periodic_time = 0;  in timer_cancel_etc()
229     /* see if we've just modified the head of the current cpu timer queue */  in timer_cancel_etc()
232         LTRACEF("clearing old hw timer, nothing in the queue\n");  in timer_cancel_etc()
243         LTRACEF("setting new timer to %llu\n", wakeup_time);  in timer_cancel_etc()
254     timer_t *timer;  in timer_tick()  local
271         timer = list_peek_head_type(&timers[cpu].timer_queue, timer_t, node);  in timer_tick()
272         if (likely(timer == 0))  in timer_tick()
274         LTRACEF("next item on timer queue %p at %llu now %llu (%p, arg %p)\n",  in timer_tick()
275                 timer, timer->scheduled_time, now, timer->callback, timer->arg);  in timer_tick()
276         if (likely(time_lt(now, timer->scheduled_time)))  in timer_tick()
280         LTRACEF("timer %p\n", timer);  in timer_tick()
281         DEBUG_ASSERT(timer && timer->magic == TIMER_MAGIC);  in timer_tick()
282         list_delete(&timer->node);  in timer_tick()
283         timer->running = true;  in timer_tick()
288         LTRACEF("dequeued timer %p, scheduled %llu periodic %llu\n", timer,  in timer_tick()
289                 timer->scheduled_time, timer->periodic_time);  in timer_tick()
293         bool periodic = timer->periodic_time > 0;  in timer_tick()
295         LTRACEF("timer %p firing callback %p, arg %p\n", timer, timer->callback, timer->arg);  in timer_tick()
296         KEVLOG_TIMER_CALL(timer->callback, timer->arg);  in timer_tick()
297         if (timer->callback(timer, now, timer->arg) == INT_RESCHEDULE)  in timer_tick()
304          * Check that timer did not get freed and overwritten while the callback  in timer_tick()
307         DEBUG_ASSERT(timer->magic == TIMER_MAGIC);  in timer_tick()
309         timer->running = false;  in timer_tick()
311         /* if it was a periodic timer and it hasn't been requeued  in timer_tick()
314         if (periodic && !list_in_list(&timer->node) && timer->periodic_time > 0) {  in timer_tick()
315             LTRACEF("periodic timer, period %llu\n", timer->periodic_time);  in timer_tick()
316             timer->scheduled_time = now + timer->periodic_time;  in timer_tick()
317             insert_timer_in_queue(cpu, timer);  in timer_tick()
322     /* reset the timer to the next event */  in timer_tick()
323     timer = list_peek_head_type(&timers[cpu].timer_queue, timer_t, node);  in timer_tick()
324     if (timer) {  in timer_tick()
326         DEBUG_ASSERT(time_gt(timer->scheduled_time, now));  in timer_tick()
328         LTRACEF("setting new timer for %llu nanosecs from now (%llu) for event %p\n",  in timer_tick()
329                 timer->scheduled_time - now, timer->scheduled_time, timer);  in timer_tick()
330         platform_set_oneshot_timer(timer_tick, timer->scheduled_time);  in timer_tick()
333     /* we're done manipulating the timer queue */  in timer_tick()
347     /* register for a periodic timer tick */  in timer_init()