aos/kernel/wakeup.c
Daniel Schwyn 6d444bf552 Main handout
Signed-off-by: Daniel Schwyn <daniel.schwyn@inf.ethz.ch>
2022-03-03 14:57:51 +01:00

112 lines
3.1 KiB
C

/**
* \file
* \brief DCB wakeup queue management
*/
/*
* Copyright (c) 2011, ETH Zurich.
* All rights reserved.
*
* This file is distributed under the terms in the attached LICENSE file.
* If you do not find this file, copies can be found by writing to:
* ETH Zurich D-INFK, Universitaetstrasse 6, CH-8092 Zurich. Attn: Systems Group.
*/
#include <kernel.h>
#include <dispatch.h>
#include <kcb.h> // kcb_current->wakeup_queue_head
#include <timer.h> // update_wakeup_timer()
#include <wakeup.h>
#include <systime.h>
/* wrapper to change the head, and update the next wakeup tick */
void wakeup_set_queue_head(struct dcb *h)
{
kcb_current->wakeup_queue_head = h;
#ifdef CONFIG_ONESHOT_TIMER
// we changed the first dcb in the wakeup queue, which means
// that we need to update the next tick value
systime_t next_wakeup = h ? h->wakeup_time : TIMER_INF;
update_wakeup_timer(next_wakeup);
#endif
}
static inline void set_queue_head(struct dcb *h)
{
wakeup_set_queue_head(h);
}
void wakeup_remove(struct dcb *dcb)
{
if (dcb->wakeup_time != 0) {
if (dcb->wakeup_prev == NULL) {
assert(kcb_current->wakeup_queue_head == dcb);
set_queue_head(dcb->wakeup_next);
} else {
assert(dcb->wakeup_prev->wakeup_next == dcb);
dcb->wakeup_prev->wakeup_next = dcb->wakeup_next;
}
if (dcb->wakeup_next != NULL) {
assert(dcb->wakeup_next->wakeup_prev == dcb);
dcb->wakeup_next->wakeup_prev = dcb->wakeup_prev;
}
dcb->wakeup_prev = dcb->wakeup_next = NULL;
}
// No-Op if not in queue...
}
/// Set the wakeup time for the given DCB
void wakeup_set(struct dcb *dcb, systime_t waketime)
{
assert(dcb != NULL);
// if we're already enqueued, remove first
wakeup_remove(dcb);
dcb->wakeup_time = waketime;
for (struct dcb *d = kcb_current->wakeup_queue_head, *p = NULL; ; p = d, d = d->wakeup_next) {
if (d == NULL || d->wakeup_time > waketime) {
if (p == NULL) { // insert at head
assert(d == kcb_current->wakeup_queue_head);
dcb->wakeup_prev = NULL;
dcb->wakeup_next = d;
if (d != NULL) {
d->wakeup_prev = dcb;
}
set_queue_head(dcb);
} else {
dcb->wakeup_next = d;
dcb->wakeup_prev = p;
p->wakeup_next = dcb;
if (d != NULL) {
d->wakeup_prev = dcb;
}
}
break;
}
}
}
/// Check for wakeups, given the current time
void wakeup_check(systime_t now)
{
struct dcb *d = kcb_current->wakeup_queue_head, *next = NULL;
for (; d != NULL && d->wakeup_time <= now; d = next) {
next = d->wakeup_next;
d->wakeup_time = 0;
d->wakeup_prev = d->wakeup_next = NULL;
make_runnable(d);
schedule_now(d);
}
if (d != NULL) {
d->wakeup_prev = NULL;
}
set_queue_head(d);
}
bool wakeup_is_pending(void)
{
return kcb_current->wakeup_queue_head != NULL;
}