static int fast_forward(void)
{
/*
* No task has event pending, and thus the next time we have an
* event to process must be either of:
* 1. Interrupt generator triggers an interrupt
* 2. The next wake alarm is reached
* So we should check whether an interrupt may happen, and fast
* forward to the nearest among:
* 1. When interrupt generator wakes up
* 2. When the next task wakes up
*/
int task_id = task_get_next_wake();
if (!has_interrupt_generator) {
if (task_id == TASK_ID_INVALID) {
return TASK_ID_IDLE;
} else {
force_time(tasks[task_id].wake_time);
return task_id;
}
}
if (!generator_sleeping)
return TASK_ID_IDLE;
if (task_id != TASK_ID_INVALID &&
tasks[task_id].thread != (pthread_t)NULL &&
tasks[task_id].wake_time.val < generator_sleep_deadline.val) {
force_time(tasks[task_id].wake_time);
return task_id;
} else {
force_time(generator_sleep_deadline);
return TASK_ID_IDLE;
}
}
void system_pre_init(void)
{
timestamp_t t;
if (load_time(&t))
force_time(t);
ramdata_get_persistent();
__running_copy = get_image_copy();
if (__running_copy == SYSTEM_IMAGE_UNKNOWN) {
__running_copy = SYSTEM_IMAGE_RO;
system_set_reset_flags(load_reset_flags());
}
*(uintptr_t *)(__host_flash + CONFIG_RO_MEM_OFF + 4) =
(uintptr_t)__ro_jump_resetvec;
*(uintptr_t *)(__host_flash + CONFIG_RW_MEM_OFF + 4) =
(uintptr_t)__rw_jump_resetvec;
}
/* Idle task. Executed when no tasks are ready to be scheduled. */
void __idle(void)
{
timestamp_t t0, t1;
int next_delay;
uint32_t rtc_t0, rtc_t1;
while (1) {
asm volatile("cpsid i");
t0 = get_time();
next_delay = __hw_clock_event_get() - t0.le.lo;
if (DEEP_SLEEP_ALLOWED && (next_delay > STOP_MODE_LATENCY)) {
/* deep-sleep in STOP mode */
enable_serial_wakeup(1);
/* set deep sleep bit */
CPU_SCB_SYSCTRL |= 0x4;
rtc_t0 = set_rtc_alarm(0,
next_delay - STOP_MODE_LATENCY);
asm("wfi");
CPU_SCB_SYSCTRL &= ~0x4;
enable_serial_wakeup(0);
/* re-lock the PLL */
config_hispeed_clock();
/* fast forward timer according to RTC counter */
rtc_t1 = reset_rtc_alarm();
t1.val = t0.val + (rtc_t1 - rtc_t0) * US_PER_RTC_TICK;
force_time(t1);
} else {
/* normal idle : only CPU clock stopped */
asm("wfi");
}
asm volatile("cpsie i");
}
}
