zephyr/drivers/timer/arm_arch_timer.c

151 lines
3.5 KiB
C

/*
* Copyright (c) 2019 Carlo Caione <ccaione@baylibre.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <drivers/timer/arm_arch_timer.h>
#include <drivers/timer/system_timer.h>
#include <sys_clock.h>
#include <spinlock.h>
#include <arch/cpu.h>
#define CYC_PER_TICK ((uint64_t)sys_clock_hw_cycles_per_sec() \
/ (uint64_t)CONFIG_SYS_CLOCK_TICKS_PER_SEC)
#define MAX_TICKS INT32_MAX
#define MIN_DELAY (1000)
static struct k_spinlock lock;
static volatile uint64_t last_cycle;
static void arm_arch_timer_compare_isr(const void *arg)
{
ARG_UNUSED(arg);
k_spinlock_key_t key = k_spin_lock(&lock);
uint64_t curr_cycle = arm_arch_timer_count();
uint32_t delta_ticks = (uint32_t)((curr_cycle - last_cycle) / CYC_PER_TICK);
last_cycle += delta_ticks * CYC_PER_TICK;
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
uint64_t next_cycle = last_cycle + CYC_PER_TICK;
if ((uint64_t)(next_cycle - curr_cycle) < MIN_DELAY) {
next_cycle += CYC_PER_TICK;
}
arm_arch_timer_set_compare(next_cycle);
arm_arch_timer_set_irq_mask(false);
} else {
arm_arch_timer_set_irq_mask(true);
}
k_spin_unlock(&lock, key);
sys_clock_announce(IS_ENABLED(CONFIG_TICKLESS_KERNEL) ? delta_ticks : 1);
}
int sys_clock_driver_init(const struct device *dev)
{
ARG_UNUSED(dev);
IRQ_CONNECT(ARM_ARCH_TIMER_IRQ, ARM_ARCH_TIMER_PRIO,
arm_arch_timer_compare_isr, NULL, ARM_ARCH_TIMER_FLAGS);
arm_arch_timer_init();
arm_arch_timer_set_compare(arm_arch_timer_count() + CYC_PER_TICK);
arm_arch_timer_enable(true);
irq_enable(ARM_ARCH_TIMER_IRQ);
arm_arch_timer_set_irq_mask(false);
return 0;
}
void sys_clock_set_timeout(int32_t ticks, bool idle)
{
#if defined(CONFIG_TICKLESS_KERNEL)
if (ticks == K_TICKS_FOREVER && idle) {
return;
}
ticks = (ticks == K_TICKS_FOREVER) ? MAX_TICKS : \
MIN(MAX_TICKS, MAX(ticks - 1, 0));
k_spinlock_key_t key = k_spin_lock(&lock);
uint64_t curr_cycle = arm_arch_timer_count();
uint64_t req_cycle = ticks * CYC_PER_TICK;
/* Round up to next tick boundary */
req_cycle += (curr_cycle - last_cycle) + (CYC_PER_TICK - 1);
req_cycle = (req_cycle / CYC_PER_TICK) * CYC_PER_TICK;
if ((req_cycle + last_cycle - curr_cycle) < MIN_DELAY) {
req_cycle += CYC_PER_TICK;
}
arm_arch_timer_set_compare(req_cycle + last_cycle);
arm_arch_timer_set_irq_mask(false);
k_spin_unlock(&lock, key);
#else /* CONFIG_TICKLESS_KERNEL */
ARG_UNUSED(ticks);
ARG_UNUSED(idle);
#endif
}
uint32_t sys_clock_elapsed(void)
{
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
return 0;
}
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t ret = (uint32_t)((arm_arch_timer_count() - last_cycle)
/ CYC_PER_TICK);
k_spin_unlock(&lock, key);
return ret;
}
uint32_t sys_clock_cycle_get_32(void)
{
return (uint32_t)arm_arch_timer_count();
}
#ifdef CONFIG_ARCH_HAS_CUSTOM_BUSY_WAIT
void arch_busy_wait(uint32_t usec_to_wait)
{
if (usec_to_wait == 0) {
return;
}
uint64_t start_cycles = arm_arch_timer_count();
uint64_t cycles_to_wait = sys_clock_hw_cycles_per_sec() / USEC_PER_SEC * usec_to_wait;
for (;;) {
uint64_t current_cycles = arm_arch_timer_count();
/* this handles the rollover on an unsigned 32-bit value */
if ((current_cycles - start_cycles) >= cycles_to_wait) {
break;
}
}
}
#endif
#ifdef CONFIG_SMP
void smp_timer_init(void)
{
/*
* set the initial status of timer0 of each secondary core
*/
arm_arch_timer_set_compare(arm_arch_timer_count() + CYC_PER_TICK);
arm_arch_timer_enable(true);
irq_enable(ARM_ARCH_TIMER_IRQ);
arm_arch_timer_set_irq_mask(false);
}
#endif