blob: 2454cdcca64566d0ea8c93fe361f1c6fbe37d55b [file] [log] [blame]
/*
* Copyright (c) 2020, 2021 Antony Pavlov <antonynpavlov@gmail.com>
* Copyright (c) 2021 Remy Luisant <remy@luisant.ca>
*
* Based on riscv_machine_timer.c and xtensa_sys_timer.c
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <limits.h>
#include <zephyr/init.h>
#include <zephyr/drivers/timer/system_timer.h>
#include <zephyr/irq.h>
#include <zephyr/sys_clock.h>
#include <zephyr/spinlock.h>
#include <soc.h>
#include <mips/mipsregs.h>
#define CYC_PER_TICK ((uint32_t)((uint64_t)sys_clock_hw_cycles_per_sec() \
/ (uint64_t)CONFIG_SYS_CLOCK_TICKS_PER_SEC))
#define MAX_CYC INT_MAX
#define MAX_TICKS ((MAX_CYC - CYC_PER_TICK) / CYC_PER_TICK)
#define MIN_DELAY 1000
#define TICKLESS IS_ENABLED(CONFIG_TICKLESS_KERNEL)
static struct k_spinlock lock;
static uint32_t last_count;
static ALWAYS_INLINE void set_cp0_compare(uint32_t time)
{
_mips_write_32bit_c0_register(CP0_COMPARE, time);
}
static ALWAYS_INLINE uint32_t get_cp0_count(void)
{
return _mips_read_32bit_c0_register(CP0_COUNT);
}
static void timer_isr(const void *arg)
{
ARG_UNUSED(arg);
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t now = get_cp0_count();
uint32_t dticks = ((now - last_count) / CYC_PER_TICK);
last_count = now;
if (!TICKLESS) {
uint32_t next = last_count + CYC_PER_TICK;
if (next - now < MIN_DELAY) {
next += CYC_PER_TICK;
}
set_cp0_compare(next);
}
k_spin_unlock(&lock, key);
sys_clock_announce(TICKLESS ? dticks : 1);
}
void sys_clock_set_timeout(int32_t ticks, bool idle)
{
ARG_UNUSED(idle);
if (!TICKLESS) {
return;
}
ticks = ticks == K_TICKS_FOREVER ? MAX_TICKS : ticks;
ticks = CLAMP(ticks - 1, 0, (int32_t)MAX_TICKS);
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t current_count = get_cp0_count();
uint32_t delay_wanted = ticks * CYC_PER_TICK;
/* Round up to next tick boundary. */
uint32_t adj = (current_count - last_count) + (CYC_PER_TICK - 1);
if (delay_wanted <= MAX_CYC - adj) {
delay_wanted += adj;
} else {
delay_wanted = MAX_CYC;
}
delay_wanted = (delay_wanted / CYC_PER_TICK) * CYC_PER_TICK;
if ((int32_t)(delay_wanted + last_count - current_count) < MIN_DELAY) {
delay_wanted += CYC_PER_TICK;
}
set_cp0_compare(delay_wanted + last_count);
k_spin_unlock(&lock, key);
}
uint32_t sys_clock_elapsed(void)
{
if (!TICKLESS) {
return 0;
}
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t ticks_elapsed = (get_cp0_count() - last_count) / CYC_PER_TICK;
k_spin_unlock(&lock, key);
return ticks_elapsed;
}
uint32_t sys_clock_cycle_get_32(void)
{
return get_cp0_count();
}
static int sys_clock_driver_init(void)
{
IRQ_CONNECT(MIPS_MACHINE_TIMER_IRQ, 0, timer_isr, NULL, 0);
last_count = get_cp0_count();
/*
* In a tickless system the first tick might possibly be pushed
* much further into the future than is being done here.
*/
set_cp0_compare(last_count + CYC_PER_TICK);
irq_enable(MIPS_MACHINE_TIMER_IRQ);
return 0;
}
SYS_INIT(sys_clock_driver_init, PRE_KERNEL_2,
CONFIG_SYSTEM_CLOCK_INIT_PRIORITY);