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// SPDX-License-Identifier: BSD-2-Clause
/*
* Copyright (c) 2024, Linaro Limited
*/
#include <kernel/callout.h>
#include <kernel/misc.h>
#include <kernel/spinlock.h>
#include <mm/core_memprot.h>
TAILQ_HEAD(callout_head, callout);
static unsigned int callout_sched_lock __nex_data = SPINLOCK_UNLOCK;
static size_t callout_sched_core __nex_bss;
static unsigned int callout_lock __nex_data = SPINLOCK_UNLOCK;
static const struct callout_timer_desc *callout_desc __nex_bss;
static struct callout_head callout_head __nex_data =
TAILQ_HEAD_INITIALIZER(callout_head);
static void insert_callout(struct callout *co)
{
struct callout *co2 = NULL;
TAILQ_FOREACH(co2, &callout_head, link) {
if (co->expiry_value < co2->expiry_value) {
TAILQ_INSERT_BEFORE(co2, co, link);
return;
}
}
TAILQ_INSERT_TAIL(&callout_head, co, link);
}
static void schedule_next_timeout(void)
{
const struct callout_timer_desc *desc = callout_desc;
struct callout *co = TAILQ_FIRST(&callout_head);
if (co)
desc->set_next_timeout(desc, co->expiry_value);
else
desc->disable_timeout(desc);
if (desc->is_per_cpu) {
/*
* Remember which core is supposed to receive the next
* timer interrupt. This will not disable timers on other
* CPUs, instead they will be ignored as a spurious call.
*/
cpu_spin_lock(&callout_sched_lock);
callout_sched_core = get_core_pos();
cpu_spin_unlock(&callout_sched_lock);
}
}
static bool callout_is_active(struct callout *co)
{
struct callout *co2 = NULL;
TAILQ_FOREACH(co2, &callout_head, link)
if (co2 == co)
return true;
return false;
}
void callout_rem(struct callout *co)
{
uint32_t state = 0;
state = cpu_spin_lock_xsave(&callout_lock);
if (callout_is_active(co)) {
TAILQ_REMOVE(&callout_head, co, link);
schedule_next_timeout();
}
cpu_spin_unlock_xrestore(&callout_lock, state);
}
void callout_add(struct callout *co, bool (*callback)(struct callout *co),
uint32_t ms)
{
const struct callout_timer_desc *desc = callout_desc;
uint32_t state = 0;
state = cpu_spin_lock_xsave(&callout_lock);
assert(is_nexus(co) && !callout_is_active(co) && is_unpaged(callback));
*co = (struct callout){ .callback = callback, };
if (desc) {
co->period = desc->ms_to_ticks(desc, ms);
co->expiry_value = desc->get_now(desc) + co->period;
} else {
/* This will be converted to ticks in callout_service_init(). */
co->period = ms;
}
insert_callout(co);
if (desc && co == TAILQ_FIRST(&callout_head))
schedule_next_timeout();
cpu_spin_unlock_xrestore(&callout_lock, state);
}
void callout_set_next_timeout(struct callout *co, uint32_t ms)
{
co->period = callout_desc->ms_to_ticks(callout_desc, ms);
}
void callout_service_init(const struct callout_timer_desc *desc)
{
struct callout_head tmp_head = TAILQ_HEAD_INITIALIZER(tmp_head);
struct callout *co = NULL;
uint32_t state = 0;
uint64_t now = 0;
state = cpu_spin_lock_xsave(&callout_lock);
assert(!callout_desc);
assert(is_nexus(desc) && is_unpaged(desc->disable_timeout) &&
is_unpaged(desc->set_next_timeout) &&
is_unpaged(desc->ms_to_ticks) && is_unpaged(desc->get_now));
callout_desc = desc;
now = desc->get_now(desc);
TAILQ_CONCAT(&tmp_head, &callout_head, link);
while (!TAILQ_EMPTY(&tmp_head)) {
co = TAILQ_FIRST(&tmp_head);
TAILQ_REMOVE(&tmp_head, co, link);
/*
* Periods set before the timer descriptor are in
* milliseconds since the frequency of the timer isn't
* available at that point. So update it to ticks now.
*/
co->period = desc->ms_to_ticks(desc, co->period);
co->expiry_value = now + co->period;
insert_callout(co);
}
schedule_next_timeout();
cpu_spin_unlock_xrestore(&callout_lock, state);
}
void callout_service_cb(void)
{
const struct callout_timer_desc *desc = callout_desc;
struct callout *co = NULL;
uint64_t now = 0;
if (desc->is_per_cpu) {
bool do_callout = false;
/*
* schedule_next_timeout() saves the core it was last
* called on. If there's a mismatch here it means that
* another core has been scheduled for the next callout, so
* there's no work to be done for this core and we can
* disable the timeout on this CPU.
*/
cpu_spin_lock(&callout_sched_lock);
do_callout = (get_core_pos() == callout_sched_core);
if (!do_callout)
desc->disable_timeout(desc);
cpu_spin_unlock(&callout_sched_lock);
if (!do_callout)
return;
}
cpu_spin_lock(&callout_lock);
now = desc->get_now(desc);
while (!TAILQ_EMPTY(&callout_head)) {
co = TAILQ_FIRST(&callout_head);
if (co->expiry_value > now)
break;
TAILQ_REMOVE(&callout_head, co, link);
if (co->callback(co)) {
co->expiry_value += co->period;
insert_callout(co);
}
}
schedule_next_timeout();
cpu_spin_unlock(&callout_lock);
}
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