kernel/timer.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * Copyright (c) 1997-2016 Wind River Systems, Inc.
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 #include <zephyr/kernel.h>

 #include <zephyr/init.h>
 #include <zephyr/internal/syscall_handler.h>
 #include <stdbool.h>
 #include <zephyr/spinlock.h>
 #include <ksched.h>
 #include <wait_q.h>

 static struct k_spinlock lock;

 #ifdef CONFIG_OBJ_CORE_TIMER
 static struct k_obj_type obj_type_timer;
 #endif /* CONFIG_OBJ_CORE_TIMER */

 /**
  * @brief Handle expiration of a kernel timer object.
  *
  * @param t  Timeout used by the timer.
  */
 void z_timer_expiration_handler(struct _timeout *t)
 {
 	struct k_timer *timer = CONTAINER_OF(t, struct k_timer, timeout);
 	struct k_thread *thread;
 	k_spinlock_key_t key = k_spin_lock(&lock);

 	/* In sys_clock_announce(), when a timeout expires, it is first removed
 	 * from the timeout list, then its expiration handler is called (with
 	 * unlocked interrupts). For kernel timers, the expiration handler is
 	 * this function. Usually, the timeout structure related to the timer
 	 * that is handled here will not be linked to the timeout list at this
 	 * point. But it may happen that before this function is executed and
 	 * interrupts are locked again, a given timer gets restarted from an
 	 * interrupt context that has a priority higher than the system timer
 	 * interrupt. Then, the timeout structure for this timer will turn out
 	 * to be linked to the timeout list. And in such case, since the timer
 	 * was restarted, its expiration handler should not be executed then,
 	 * so the function exits immediately.
 	 */
 	if (sys_dnode_is_linked(&t->node)) {
 		k_spin_unlock(&lock, key);
 		return;
 	}

 	/*
 	 * if the timer is periodic, start it again; don't add _TICK_ALIGN
 	 * since we're already aligned to a tick boundary
 	 */
 	if (!K_TIMEOUT_EQ(timer->period, K_NO_WAIT) &&
 	    !K_TIMEOUT_EQ(timer->period, K_FOREVER)) {
 		k_timeout_t next = timer->period;

 		/* see note about z_add_timeout() in z_impl_k_timer_start() */
 		next.ticks = MAX(next.ticks - 1, 0);

 #ifdef CONFIG_TIMEOUT_64BIT
 		/* Exploit the fact that uptime during a kernel
 		 * timeout handler reflects the time of the scheduled
 		 * event and not real time to get some inexpensive
 		 * protection against late interrupts.  If we're
 		 * delayed for any reason, we still end up calculating
 		 * the next expiration as a regular stride from where
 		 * we "should" have run.  Requires absolute timeouts.
 		 * (Note offset by one: we're nominally at the
 		 * beginning of a tick, so need to defeat the "round
 		 * down" behavior on timeout addition).
 		 */
 		next = K_TIMEOUT_ABS_TICKS(k_uptime_ticks() + 1 + next.ticks);
 #endif /* CONFIG_TIMEOUT_64BIT */
 		z_add_timeout(&timer->timeout, z_timer_expiration_handler,
 			      next);
 	}

 	/* update timer's status */
 	timer->status += 1U;

 	/* invoke timer expiry function */
 	if (timer->expiry_fn != NULL) {
 		/* Unlock for user handler. */
 		k_spin_unlock(&lock, key);
 		timer->expiry_fn(timer);
 		key = k_spin_lock(&lock);
 	}

 	if (!IS_ENABLED(CONFIG_MULTITHREADING)) {
 		k_spin_unlock(&lock, key);
 		return;
 	}

 	thread = z_waitq_head(&timer->wait_q);

 	if (thread == NULL) {
 		k_spin_unlock(&lock, key);
 		return;
 	}

 	z_unpend_thread_no_timeout(thread);

 	arch_thread_return_value_set(thread, 0);

 	k_spin_unlock(&lock, key);

 	z_ready_thread(thread);
 }


 void k_timer_init(struct k_timer *timer,
 			 k_timer_expiry_t expiry_fn,
 			 k_timer_stop_t stop_fn)
 {
 	timer->expiry_fn = expiry_fn;
 	timer->stop_fn = stop_fn;
 	timer->status = 0U;

 	if (IS_ENABLED(CONFIG_MULTITHREADING)) {
 		z_waitq_init(&timer->wait_q);
 	}

 	z_init_timeout(&timer->timeout);

 	SYS_PORT_TRACING_OBJ_INIT(k_timer, timer);

 	timer->user_data = NULL;

 	k_object_init(timer);

 #ifdef CONFIG_OBJ_CORE_TIMER
 	k_obj_core_init_and_link(K_OBJ_CORE(timer), &obj_type_timer);
 #endif /* CONFIG_OBJ_CORE_TIMER */
 }


 void z_impl_k_timer_start(struct k_timer *timer, k_timeout_t duration,
 			  k_timeout_t period)
 {
 	SYS_PORT_TRACING_OBJ_FUNC(k_timer, start, timer, duration, period);

 	/* Acquire spinlock to ensure safety during concurrent calls to
 	 * k_timer_start for scheduling or rescheduling. This is necessary
 	 * since k_timer_start can be preempted, especially for the same
 	 * timer instance.
 	 */
 	k_spinlock_key_t key = k_spin_lock(&lock);

 	if (K_TIMEOUT_EQ(duration, K_FOREVER)) {
 		k_spin_unlock(&lock, key);
 		return;
 	}

 	/* z_add_timeout() always adds one to the incoming tick count
 	 * to round up to the next tick (by convention it waits for
 	 * "at least as long as the specified timeout"), but the
 	 * period interval is always guaranteed to be reset from
 	 * within the timer ISR, so no round up is desired and 1 is
 	 * subtracted in there.
 	 *
 	 * Note that the duration (!) value gets the same treatment
 	 * for backwards compatibility.  This is unfortunate
 	 * (i.e. k_timer_start() doesn't treat its initial sleep
 	 * argument the same way k_sleep() does), but historical.  The
 	 * timer_api test relies on this behavior.
 	 */
 	if (Z_TICK_ABS(duration.ticks) < 0) {
 		duration.ticks = MAX(duration.ticks - 1, 0);
 	}

 	(void)z_abort_timeout(&timer->timeout);
 	timer->period = period;
 	timer->status = 0U;

 	z_add_timeout(&timer->timeout, z_timer_expiration_handler,
 		     duration);

 	k_spin_unlock(&lock, key);
 }

 #ifdef CONFIG_USERSPACE
 static inline void z_vrfy_k_timer_start(struct k_timer *timer,
 					k_timeout_t duration,
 					k_timeout_t period)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	z_impl_k_timer_start(timer, duration, period);
 }
 #include <zephyr/syscalls/k_timer_start_mrsh.c>
 #endif /* CONFIG_USERSPACE */

 void z_impl_k_timer_stop(struct k_timer *timer)
 {
 	SYS_PORT_TRACING_OBJ_FUNC(k_timer, stop, timer);

 	bool inactive = (z_abort_timeout(&timer->timeout) != 0);

 	if (inactive) {
 		return;
 	}

 	if (timer->stop_fn != NULL) {
 		timer->stop_fn(timer);
 	}

 	if (IS_ENABLED(CONFIG_MULTITHREADING)) {
 		struct k_thread *pending_thread = z_unpend1_no_timeout(&timer->wait_q);

 		if (pending_thread != NULL) {
 			z_ready_thread(pending_thread);
 			z_reschedule_unlocked();
 		}
 	}
 }

 #ifdef CONFIG_USERSPACE
 static inline void z_vrfy_k_timer_stop(struct k_timer *timer)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	z_impl_k_timer_stop(timer);
 }
 #include <zephyr/syscalls/k_timer_stop_mrsh.c>
 #endif /* CONFIG_USERSPACE */

 uint32_t z_impl_k_timer_status_get(struct k_timer *timer)
 {
 	k_spinlock_key_t key = k_spin_lock(&lock);
 	uint32_t result = timer->status;

 	timer->status = 0U;
 	k_spin_unlock(&lock, key);

 	return result;
 }

 #ifdef CONFIG_USERSPACE
 static inline uint32_t z_vrfy_k_timer_status_get(struct k_timer *timer)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	return z_impl_k_timer_status_get(timer);
 }
 #include <zephyr/syscalls/k_timer_status_get_mrsh.c>
 #endif /* CONFIG_USERSPACE */

 uint32_t z_impl_k_timer_status_sync(struct k_timer *timer)
 {
 	__ASSERT(!arch_is_in_isr(), "");
 	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_timer, status_sync, timer);

 	if (!IS_ENABLED(CONFIG_MULTITHREADING)) {
 		uint32_t result;

 		do {
 			k_spinlock_key_t key = k_spin_lock(&lock);

 			if (!z_is_inactive_timeout(&timer->timeout)) {
 				result = *(volatile uint32_t *)&timer->status;
 				timer->status = 0U;
 				k_spin_unlock(&lock, key);
 				if (result > 0) {
 					break;
 				}
 			} else {
 				result = timer->status;
 				k_spin_unlock(&lock, key);
 				break;
 			}
 		} while (true);

 		return result;
 	}

 	k_spinlock_key_t key = k_spin_lock(&lock);
 	uint32_t result = timer->status;

 	if (result == 0U) {
 		if (!z_is_inactive_timeout(&timer->timeout)) {
 			SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_timer, status_sync, timer, K_FOREVER);

 			/* wait for timer to expire or stop */
 			(void)z_pend_curr(&lock, key, &timer->wait_q, K_FOREVER);

 			/* get updated timer status */
 			key = k_spin_lock(&lock);
 			result = timer->status;
 		} else {
 			/* timer is already stopped */
 		}
 	} else {
 		/* timer has already expired at least once */
 	}

 	timer->status = 0U;
 	k_spin_unlock(&lock, key);

 	/**
 	 * @note	New tracing hook
 	 */
 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_timer, status_sync, timer, result);

 	return result;
 }

 #ifdef CONFIG_USERSPACE
 static inline uint32_t z_vrfy_k_timer_status_sync(struct k_timer *timer)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	return z_impl_k_timer_status_sync(timer);
 }
 #include <zephyr/syscalls/k_timer_status_sync_mrsh.c>

 static inline k_ticks_t z_vrfy_k_timer_remaining_ticks(
 						const struct k_timer *timer)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	return z_impl_k_timer_remaining_ticks(timer);
 }
 #include <zephyr/syscalls/k_timer_remaining_ticks_mrsh.c>

 static inline k_ticks_t z_vrfy_k_timer_expires_ticks(
 						const struct k_timer *timer)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	return z_impl_k_timer_expires_ticks(timer);
 }
 #include <zephyr/syscalls/k_timer_expires_ticks_mrsh.c>

 static inline void *z_vrfy_k_timer_user_data_get(const struct k_timer *timer)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	return z_impl_k_timer_user_data_get(timer);
 }
 #include <zephyr/syscalls/k_timer_user_data_get_mrsh.c>

 static inline void z_vrfy_k_timer_user_data_set(struct k_timer *timer,
 						void *user_data)
 {
 	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	z_impl_k_timer_user_data_set(timer, user_data);
 }
 #include <zephyr/syscalls/k_timer_user_data_set_mrsh.c>

 #endif /* CONFIG_USERSPACE */

 #ifdef CONFIG_OBJ_CORE_TIMER
 static int init_timer_obj_core_list(void)
 {
 	/* Initialize timer object type */

 	z_obj_type_init(&obj_type_timer, K_OBJ_TYPE_TIMER_ID,
 			offsetof(struct k_timer, obj_core));

 	/* Initialize and link statically defined timers */

 	STRUCT_SECTION_FOREACH(k_timer, timer) {
 		k_obj_core_init_and_link(K_OBJ_CORE(timer), &obj_type_timer);
 	}

 	return 0;
 }
 SYS_INIT(init_timer_obj_core_list, PRE_KERNEL_1,
 	 CONFIG_KERNEL_INIT_PRIORITY_OBJECTS);
 #endif /* CONFIG_OBJ_CORE_TIMER */
	/*
	* Copyright (c) 1997-2016 Wind River Systems, Inc.
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	#include <zephyr/kernel.h>

	#include <zephyr/init.h>
	#include <zephyr/internal/syscall_handler.h>
	#include <stdbool.h>
	#include <zephyr/spinlock.h>
	#include <ksched.h>
	#include <wait_q.h>

	static struct k_spinlock lock;

	#ifdef CONFIG_OBJ_CORE_TIMER
	static struct k_obj_type obj_type_timer;
	#endif /* CONFIG_OBJ_CORE_TIMER */

	/**
	* @brief Handle expiration of a kernel timer object.
	*
	* @param t Timeout used by the timer.
	*/
	void z_timer_expiration_handler(struct _timeout *t)
	{
	struct k_timer *timer = CONTAINER_OF(t, struct k_timer, timeout);
	struct k_thread *thread;
	k_spinlock_key_t key = k_spin_lock(&lock);

	/* In sys_clock_announce(), when a timeout expires, it is first removed
	* from the timeout list, then its expiration handler is called (with
	* unlocked interrupts). For kernel timers, the expiration handler is
	* this function. Usually, the timeout structure related to the timer
	* that is handled here will not be linked to the timeout list at this
	* point. But it may happen that before this function is executed and
	* interrupts are locked again, a given timer gets restarted from an
	* interrupt context that has a priority higher than the system timer
	* interrupt. Then, the timeout structure for this timer will turn out
	* to be linked to the timeout list. And in such case, since the timer
	* was restarted, its expiration handler should not be executed then,
	* so the function exits immediately.
	*/
	if (sys_dnode_is_linked(&t->node)) {
	k_spin_unlock(&lock, key);
	return;
	}

	/*
	* if the timer is periodic, start it again; don't add _TICK_ALIGN
	* since we're already aligned to a tick boundary
	*/
	if (!K_TIMEOUT_EQ(timer->period, K_NO_WAIT) &&
	!K_TIMEOUT_EQ(timer->period, K_FOREVER)) {
	k_timeout_t next = timer->period;

	/* see note about z_add_timeout() in z_impl_k_timer_start() */
	next.ticks = MAX(next.ticks - 1, 0);

	#ifdef CONFIG_TIMEOUT_64BIT
	/* Exploit the fact that uptime during a kernel
	* timeout handler reflects the time of the scheduled
	* event and not real time to get some inexpensive
	* protection against late interrupts. If we're
	* delayed for any reason, we still end up calculating
	* the next expiration as a regular stride from where
	* we "should" have run. Requires absolute timeouts.
	* (Note offset by one: we're nominally at the
	* beginning of a tick, so need to defeat the "round
	* down" behavior on timeout addition).
	*/
	next = K_TIMEOUT_ABS_TICKS(k_uptime_ticks() + 1 + next.ticks);
	#endif /* CONFIG_TIMEOUT_64BIT */
	z_add_timeout(&timer->timeout, z_timer_expiration_handler,
	next);
	}

	/* update timer's status */
	timer->status += 1U;

	/* invoke timer expiry function */
	if (timer->expiry_fn != NULL) {
	/* Unlock for user handler. */
	k_spin_unlock(&lock, key);
	timer->expiry_fn(timer);
	key = k_spin_lock(&lock);
	}

	if (!IS_ENABLED(CONFIG_MULTITHREADING)) {
	k_spin_unlock(&lock, key);
	return;
	}

	thread = z_waitq_head(&timer->wait_q);

	if (thread == NULL) {
	k_spin_unlock(&lock, key);
	return;
	}

	z_unpend_thread_no_timeout(thread);

	arch_thread_return_value_set(thread, 0);

	k_spin_unlock(&lock, key);

	z_ready_thread(thread);
	}


	void k_timer_init(struct k_timer *timer,
	k_timer_expiry_t expiry_fn,
	k_timer_stop_t stop_fn)
	{
	timer->expiry_fn = expiry_fn;
	timer->stop_fn = stop_fn;
	timer->status = 0U;

	if (IS_ENABLED(CONFIG_MULTITHREADING)) {
	z_waitq_init(&timer->wait_q);
	}

	z_init_timeout(&timer->timeout);

	SYS_PORT_TRACING_OBJ_INIT(k_timer, timer);

	timer->user_data = NULL;

	k_object_init(timer);

	#ifdef CONFIG_OBJ_CORE_TIMER
	k_obj_core_init_and_link(K_OBJ_CORE(timer), &obj_type_timer);
	#endif /* CONFIG_OBJ_CORE_TIMER */
	}


	void z_impl_k_timer_start(struct k_timer *timer, k_timeout_t duration,
	k_timeout_t period)
	{
	SYS_PORT_TRACING_OBJ_FUNC(k_timer, start, timer, duration, period);

	/* Acquire spinlock to ensure safety during concurrent calls to
	* k_timer_start for scheduling or rescheduling. This is necessary
	* since k_timer_start can be preempted, especially for the same
	* timer instance.
	*/
	k_spinlock_key_t key = k_spin_lock(&lock);

	if (K_TIMEOUT_EQ(duration, K_FOREVER)) {
	k_spin_unlock(&lock, key);
	return;
	}

	/* z_add_timeout() always adds one to the incoming tick count
	* to round up to the next tick (by convention it waits for
	* "at least as long as the specified timeout"), but the
	* period interval is always guaranteed to be reset from
	* within the timer ISR, so no round up is desired and 1 is
	* subtracted in there.
	*
	* Note that the duration (!) value gets the same treatment
	* for backwards compatibility. This is unfortunate
	* (i.e. k_timer_start() doesn't treat its initial sleep
	* argument the same way k_sleep() does), but historical. The
	* timer_api test relies on this behavior.
	*/
	if (Z_TICK_ABS(duration.ticks) < 0) {
	duration.ticks = MAX(duration.ticks - 1, 0);
	}

	(void)z_abort_timeout(&timer->timeout);
	timer->period = period;
	timer->status = 0U;

	z_add_timeout(&timer->timeout, z_timer_expiration_handler,
	duration);

	k_spin_unlock(&lock, key);
	}

	#ifdef CONFIG_USERSPACE
	static inline void z_vrfy_k_timer_start(struct k_timer *timer,
	k_timeout_t duration,
	k_timeout_t period)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	z_impl_k_timer_start(timer, duration, period);
	}
	#include <zephyr/syscalls/k_timer_start_mrsh.c>
	#endif /* CONFIG_USERSPACE */

	void z_impl_k_timer_stop(struct k_timer *timer)
	{
	SYS_PORT_TRACING_OBJ_FUNC(k_timer, stop, timer);

	bool inactive = (z_abort_timeout(&timer->timeout) != 0);

	if (inactive) {
	return;
	}

	if (timer->stop_fn != NULL) {
	timer->stop_fn(timer);
	}

	if (IS_ENABLED(CONFIG_MULTITHREADING)) {
	struct k_thread *pending_thread = z_unpend1_no_timeout(&timer->wait_q);

	if (pending_thread != NULL) {
	z_ready_thread(pending_thread);
	z_reschedule_unlocked();
	}
	}
	}

	#ifdef CONFIG_USERSPACE
	static inline void z_vrfy_k_timer_stop(struct k_timer *timer)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	z_impl_k_timer_stop(timer);
	}
	#include <zephyr/syscalls/k_timer_stop_mrsh.c>
	#endif /* CONFIG_USERSPACE */

	uint32_t z_impl_k_timer_status_get(struct k_timer *timer)
	{
	k_spinlock_key_t key = k_spin_lock(&lock);
	uint32_t result = timer->status;

	timer->status = 0U;
	k_spin_unlock(&lock, key);

	return result;
	}

	#ifdef CONFIG_USERSPACE
	static inline uint32_t z_vrfy_k_timer_status_get(struct k_timer *timer)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	return z_impl_k_timer_status_get(timer);
	}
	#include <zephyr/syscalls/k_timer_status_get_mrsh.c>
	#endif /* CONFIG_USERSPACE */

	uint32_t z_impl_k_timer_status_sync(struct k_timer *timer)
	{
	__ASSERT(!arch_is_in_isr(), "");
	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_timer, status_sync, timer);

	if (!IS_ENABLED(CONFIG_MULTITHREADING)) {
	uint32_t result;

	do {
	k_spinlock_key_t key = k_spin_lock(&lock);

	if (!z_is_inactive_timeout(&timer->timeout)) {
	result = (volatile uint32_t )&timer->status;
	timer->status = 0U;
	k_spin_unlock(&lock, key);
	if (result > 0) {
	break;
	}
	} else {
	result = timer->status;
	k_spin_unlock(&lock, key);
	break;
	}
	} while (true);

	return result;
	}

	k_spinlock_key_t key = k_spin_lock(&lock);
	uint32_t result = timer->status;

	if (result == 0U) {
	if (!z_is_inactive_timeout(&timer->timeout)) {
	SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_timer, status_sync, timer, K_FOREVER);

	/* wait for timer to expire or stop */
	(void)z_pend_curr(&lock, key, &timer->wait_q, K_FOREVER);

	/* get updated timer status */
	key = k_spin_lock(&lock);
	result = timer->status;
	} else {
	/* timer is already stopped */
	}
	} else {
	/* timer has already expired at least once */
	}

	timer->status = 0U;
	k_spin_unlock(&lock, key);

	/**
	* @note New tracing hook
	*/
	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_timer, status_sync, timer, result);

	return result;
	}

	#ifdef CONFIG_USERSPACE
	static inline uint32_t z_vrfy_k_timer_status_sync(struct k_timer *timer)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	return z_impl_k_timer_status_sync(timer);
	}
	#include <zephyr/syscalls/k_timer_status_sync_mrsh.c>

	static inline k_ticks_t z_vrfy_k_timer_remaining_ticks(
	const struct k_timer *timer)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	return z_impl_k_timer_remaining_ticks(timer);
	}
	#include <zephyr/syscalls/k_timer_remaining_ticks_mrsh.c>

	static inline k_ticks_t z_vrfy_k_timer_expires_ticks(
	const struct k_timer *timer)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	return z_impl_k_timer_expires_ticks(timer);
	}
	#include <zephyr/syscalls/k_timer_expires_ticks_mrsh.c>

	static inline void z_vrfy_k_timer_user_data_get(const struct k_timer timer)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	return z_impl_k_timer_user_data_get(timer);
	}
	#include <zephyr/syscalls/k_timer_user_data_get_mrsh.c>

	static inline void z_vrfy_k_timer_user_data_set(struct k_timer *timer,
	void *user_data)
	{
	K_OOPS(K_SYSCALL_OBJ(timer, K_OBJ_TIMER));
	z_impl_k_timer_user_data_set(timer, user_data);
	}
	#include <zephyr/syscalls/k_timer_user_data_set_mrsh.c>

	#endif /* CONFIG_USERSPACE */

	#ifdef CONFIG_OBJ_CORE_TIMER
	static int init_timer_obj_core_list(void)
	{
	/* Initialize timer object type */

	z_obj_type_init(&obj_type_timer, K_OBJ_TYPE_TIMER_ID,
	offsetof(struct k_timer, obj_core));

	/* Initialize and link statically defined timers */

	STRUCT_SECTION_FOREACH(k_timer, timer) {
	k_obj_core_init_and_link(K_OBJ_CORE(timer), &obj_type_timer);
	}

	return 0;
	}
	SYS_INIT(init_timer_obj_core_list, PRE_KERNEL_1,
	CONFIG_KERNEL_INIT_PRIORITY_OBJECTS);
	#endif /* CONFIG_OBJ_CORE_TIMER */