zephyr/kernel/microkernel/k_timer.c

557 lines
12 KiB
C

/* timer kernel services */
/*
* Copyright (c) 1997-2015 Wind River Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1) Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2) Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3) Neither the name of Wind River Systems nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <microkernel.h>
#include <toolchain.h>
#include <sections.h>
#include <micro_private.h>
#include <drivers/system_timer.h>
extern struct k_timer _k_timer_blocks[];
struct k_timer *_k_timer_list_head = NULL;
struct k_timer *_k_timer_list_tail = NULL;
/**
*
* @brief Convert timer pointer to timer object identifier
*
* This routine converts a timer pointer into a timer object identifier.
*
* This algorithm relies on the fact that subtracting two pointers that point
* to elements of an array returns the difference between the array subscripts
* of those elements. (That is, "&a[j]-&a[i]" returns "j-i".)
*
* This algorithm also set the upper 16 bits of the object identifier
* to the same value utilized by the microkernel system generator.
*
* @return timer object identifier
*/
static inline ktimer_t _timer_ptr_to_id(struct k_timer *timer)
{
return (ktimer_t)(0x00010000u + (uint32_t)(timer - &_k_timer_blocks[0]));
}
/**
*
* @brief Convert timer object identifier to timer pointer
*
* This routine converts a timer object identifier into a timer pointer.
*
* @return timer pointer
*/
static inline struct k_timer *_timer_id_to_ptr(ktimer_t timer)
{
return &_k_timer_blocks[OBJ_INDEX(timer)];
}
/**
*
* @brief Insert a timer into the timer queue
*
* @return N/A
*/
void _k_timer_enlist(struct k_timer *T)
{
struct k_timer *P = _k_timer_list_head;
struct k_timer *Q = NULL;
while (P && (T->duration > P->duration)) {
T->duration -= P->duration;
Q = P;
P = P->Forw;
}
if (P) {
P->duration -= T->duration;
P->Back = T;
} else {
_k_timer_list_tail = T;
}
if (Q) {
Q->Forw = T;
} else {
_k_timer_list_head = T;
}
T->Forw = P;
T->Back = Q;
}
/**
*
* @brief Remove a timer from the timer queue
*
* @return N/A
*/
void _k_timer_delist(struct k_timer *T)
{
struct k_timer *P = T->Forw;
struct k_timer *Q = T->Back;
if (P) {
P->duration += T->duration;
P->Back = Q;
} else
_k_timer_list_tail = Q;
if (Q)
Q->Forw = P;
else
_k_timer_list_head = P;
T->duration = -1;
}
/**
*
* @brief Allocate timer used for command packet timeout
*
* Allocates timer for command packet and inserts it into the timer queue.
*
* @return N/A
*/
void _k_timeout_alloc(struct k_args *P)
{
struct k_timer *T;
GETTIMER(T);
T->duration = P->Time.ticks;
T->period = 0;
T->Args = P;
_k_timer_enlist(T);
P->Time.timer = T;
}
/**
*
* @brief Cancel timer used for command packet timeout
*
* Cancels timer (if not already expired), then reschedules the command packet
* for further processing.
*
* The command that is processed following cancellation is typically NOT the
* command that would have occurred had the timeout expired on its own.
*
* @return N/A
*/
void _k_timeout_cancel(struct k_args *A)
{
struct k_timer *T = A->Time.timer;
if (T->duration != -1) {
_k_timer_delist(T);
TO_ALIST(&_k_command_stack, A);
}
}
/**
*
* @brief Free timer used for command packet timeout
*
* Cancels timer (if not already expired), then frees it.
*
* @return N/A
*/
void _k_timeout_free(struct k_timer *T)
{
if (T->duration != -1)
_k_timer_delist(T);
FREETIMER(T);
}
/**
*
* @brief Handle expired timers
*
* Process the sorted list of timers associated with waiting tasks and
* activate each task whose timer has now expired.
*
* With tickless idle, a tick announcement may encompass multiple ticks.
* Due to limitations of the underlying timer driver, the number of elapsed
* ticks may -- under very rare circumstances -- exceed the first timer's
* remaining tick count, although never by more a single tick. This means that
* a task timer may occasionally expire one tick later than it was scheduled to,
* and that a periodic timer may exhibit a slow, ever-increasing degree of drift
* from the main system timer over long intervals.
*
* @return N/A
*
* \NOMANUAL
*/
void _k_timer_list_update(int ticks)
{
struct k_timer *T;
while (_k_timer_list_head != NULL) {
_k_timer_list_head->duration -= ticks;
if (_k_timer_list_head->duration > 0) {
return;
}
T = _k_timer_list_head;
if (T == _k_timer_list_tail) {
_k_timer_list_head = _k_timer_list_tail = NULL;
} else {
_k_timer_list_head = T->Forw;
_k_timer_list_head->Back = NULL;
}
if (T->period) {
T->duration = T->period;
_k_timer_enlist(T);
} else {
T->duration = -1;
}
TO_ALIST(&_k_command_stack, T->Args);
ticks = 0; /* don't decrement duration for subsequent timer(s) */
}
}
/**
*
* @brief Handle timer allocation request
*
* This routine, called by K_swapper(), handles the request for allocating a
* timer.
*
* @param P Pointer to timer allocation request arguments.
*
* @return N/A
*/
void _k_timer_alloc(struct k_args *P)
{
struct k_timer *T;
struct k_args *A;
GETTIMER(T);
P->Args.c1.timer = T;
GETARGS(A);
T->Args = A;
T->duration = -1; /* -1 indicates that timer is disabled */
}
/**
*
* @brief Allocate a timer and return its object identifier
*
* @return timer identifier
*/
ktimer_t task_timer_alloc(void)
{
struct k_args A;
A.Comm = TALLOC;
KERNEL_ENTRY(&A);
return _timer_ptr_to_id(A.Args.c1.timer);
}
/**
*
* @brief Handle timer deallocation request
*
* This routine, called by K_swapper(), handles the request for deallocating a
* timer.
*
* @return N/A
*/
void _k_timer_dealloc(struct k_args *P)
{
struct k_timer *T = P->Args.c1.timer;
struct k_args *A = T->Args;
if (T->duration != -1)
_k_timer_delist(T);
FREETIMER(T);
FREEARGS(A);
}
/**
*
* @brief Deallocate a timer
*
* This routine frees the resources associated with the timer. If a timer was
* started, it has to be stopped using task_timer_stop() before it can be freed.
*
* @param timer Timer to deallocate.
*
* @return N/A
*/
void task_timer_free(ktimer_t timer)
{
struct k_args A;
A.Comm = TDEALLOC;
A.Args.c1.timer = _timer_id_to_ptr(timer);
KERNEL_ENTRY(&A);
}
/**
*
* @brief Handle start timer request
*
* This routine, called by K_swapper(), handles the start timer request from
* both task_timer_start() and task_timer_restart().
*
* @param P Pointer to timer start request arguments.
*
* @return N/A
*/
void _k_timer_start(struct k_args *P)
{
struct k_timer *T = P->Args.c1.timer; /* ptr to the timer to start */
if (T->duration != -1) { /* Stop the timer if it is active */
_k_timer_delist(T);
}
T->duration = (int32_t)P->Args.c1.time1; /* Set the initial delay */
T->period = P->Args.c1.time2; /* Set the period */
/*
* Either the initial delay and/or the period is invalid. Mark
* the timer as inactive.
*/
if ((T->duration < 0) || (T->period < 0)) {
T->duration = -1;
return;
}
if (T->duration == 0) {
if (T->period != 0) {/* Match the initial delay to the period. */
T->duration = T->period;
} else { /* duration=0, period=0 is an invalid combination. */
T->duration = -1; /* Mark the timer as invalid. */
return;
}
}
/* Track the semaphore to signal for when the timer expires. */
if (P->Args.c1.sema != ENDLIST) {
T->Args->Comm = SIGNALS;
T->Args->Args.s1.sema = P->Args.c1.sema;
}
_k_timer_enlist(T);
}
/**
*
* @brief Start or restart the specified low resolution timer
*
* This routine starts or restarts the specified low resolution timer.
*
* When the specified number of ticks, set by <duration>, expires, the semaphore
* is signalled. The timer repeats the expiration/signal cycle each time
* <period> ticks has elapsed.
*
* Setting <period> to 0 stops the timer at the end of the initial delay.
* Setting <duration> to 0 will cause an initial delay equal to the repetition
* interval. If both <duration> and <period> are set to 0, or if one or both of
* the values is invalid (negative), then this kernel API acts like a
* task_timer_stop(): if the allocated timer was still running (from a
* previous call), it will be cancelled; if not, nothing will happen.
*
* @param timer Timer to start.
* @param duration Initial delay in ticks.
* @param period Repetition interval in ticks.
* @param sema Semaphore to signal.
*
* @return N/A
*/
void task_timer_start(ktimer_t timer, int32_t duration, int32_t period,
ksem_t sema)
{
struct k_args A;
A.Comm = TSTART;
A.Args.c1.timer = _timer_id_to_ptr(timer);
A.Args.c1.time1 = (int64_t)duration;
A.Args.c1.time2 = period;
A.Args.c1.sema = sema;
KERNEL_ENTRY(&A);
}
/**
*
* @brief Restart a timer
*
* This routine restarts the timer specified by <timer>.
*
* @param timer Timer to restart.
* @param duration Initial delay.
* @param period Repetition interval.
*
* @return N/A
*/
void task_timer_restart(ktimer_t timer, int32_t duration, int32_t period)
{
struct k_args A;
A.Comm = TSTART;
A.Args.c1.timer = _timer_id_to_ptr(timer);
A.Args.c1.time1 = (int64_t)duration;
A.Args.c1.time2 = period;
A.Args.c1.sema = ENDLIST;
KERNEL_ENTRY(&A);
}
/**
*
* @brief Handle stop timer request
*
* This routine, called by K_swapper(), handles the request for stopping a
* timer.
*
* @return N/A
*/
void _k_timer_stop(struct k_args *P)
{
struct k_timer *T = P->Args.c1.timer;
if (T->duration != -1)
_k_timer_delist(T);
}
/**
*
* @brief Stop a timer
*
* This routine stops the specified timer. If the timer period has already
* elapsed, the call has no effect.
*
* @param timer Timer to stop.
*
* @return N/A
*/
void task_timer_stop(ktimer_t timer)
{
struct k_args A;
A.Comm = TSTOP;
A.Args.c1.timer = _timer_id_to_ptr(timer);
KERNEL_ENTRY(&A);
}
/**
*
* @brief Handle internally issued task wakeup request
*
* This routine, called by K_swapper(), handles the request for waking a task
* at the end of its sleep period.
*
* @return N/A
*/
void _k_task_wakeup(struct k_args *P)
{
struct k_timer *T;
struct k_proc *X;
X = P->Ctxt.proc;
T = P->Time.timer;
FREETIMER(T);
_k_state_bit_reset(X, TF_TIME);
}
/**
*
* @brief Handle task sleep request
*
* This routine, called by K_swapper(), handles the request for putting a task
* to sleep.
*
* @return N/A
*/
void _k_task_sleep(struct k_args *P)
{
struct k_timer *T;
if ((P->Time.ticks) <= 0) {
return;
}
GETTIMER(T);
T->duration = P->Time.ticks;
T->period = 0;
T->Args = P;
P->Comm = WAKEUP;
P->Ctxt.proc = _k_current_task;
P->Time.timer = T;
_k_timer_enlist(T);
_k_state_bit_set(_k_current_task, TF_TIME);
}
/**
*
* @brief Sleep for a number of ticks
*
* This routine suspends the calling task for the specified number of timer
* ticks. When the task is awakened, it is rescheduled according to its
* priority.
*
* @param ticks Number of ticks for which to sleep.
*
* @return N/A
*/
void task_sleep(int32_t ticks)
{
struct k_args A;
A.Comm = SLEEP;
A.Time.ticks = ticks;
KERNEL_ENTRY(&A);
}