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// SPDX-License-Identifier: GPL-2.0
/*
* Common time service routines for LoongArch machines.
*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/sched_clock.h>
#include <linux/spinlock.h>
#include <asm/cpu-features.h>
#include <asm/loongarch.h>
#include <asm/time.h>
u64 cpu_clock_freq;
EXPORT_SYMBOL(cpu_clock_freq);
u64 const_clock_freq;
EXPORT_SYMBOL(const_clock_freq);
static DEFINE_RAW_SPINLOCK(state_lock);
static DEFINE_PER_CPU(struct clock_event_device, constant_clockevent_device);
static void constant_event_handler(struct clock_event_device *dev)
{
}
static irqreturn_t constant_timer_interrupt(int irq, void *data)
{
int cpu = smp_processor_id();
struct clock_event_device *cd;
/* Clear Timer Interrupt */
write_csr_tintclear(CSR_TINTCLR_TI);
cd = &per_cpu(constant_clockevent_device, cpu);
cd->event_handler(cd);
return IRQ_HANDLED;
}
static int constant_set_state_oneshot(struct clock_event_device *evt)
{
unsigned long timer_config;
raw_spin_lock(&state_lock);
timer_config = csr_read64(LOONGARCH_CSR_TCFG);
timer_config |= CSR_TCFG_EN;
timer_config &= ~CSR_TCFG_PERIOD;
csr_write64(timer_config, LOONGARCH_CSR_TCFG);
raw_spin_unlock(&state_lock);
return 0;
}
static int constant_set_state_periodic(struct clock_event_device *evt)
{
unsigned long period;
unsigned long timer_config;
raw_spin_lock(&state_lock);
period = const_clock_freq / HZ;
timer_config = period & CSR_TCFG_VAL;
timer_config |= (CSR_TCFG_PERIOD | CSR_TCFG_EN);
csr_write64(timer_config, LOONGARCH_CSR_TCFG);
raw_spin_unlock(&state_lock);
return 0;
}
static int constant_set_state_shutdown(struct clock_event_device *evt)
{
unsigned long timer_config;
raw_spin_lock(&state_lock);
timer_config = csr_read64(LOONGARCH_CSR_TCFG);
timer_config &= ~CSR_TCFG_EN;
csr_write64(timer_config, LOONGARCH_CSR_TCFG);
raw_spin_unlock(&state_lock);
return 0;
}
static int constant_timer_next_event(unsigned long delta, struct clock_event_device *evt)
{
unsigned long timer_config;
delta &= CSR_TCFG_VAL;
timer_config = delta | CSR_TCFG_EN;
csr_write64(timer_config, LOONGARCH_CSR_TCFG);
return 0;
}
static unsigned long __init get_loops_per_jiffy(void)
{
unsigned long lpj = (unsigned long)const_clock_freq;
do_div(lpj, HZ);
return lpj;
}
static long init_offset __nosavedata;
void save_counter(void)
{
init_offset = drdtime();
}
void sync_counter(void)
{
/* Ensure counter begin at 0 */
csr_write64(init_offset, LOONGARCH_CSR_CNTC);
}
int constant_clockevent_init(void)
{
unsigned int cpu = smp_processor_id();
unsigned long min_delta = 0x600;
unsigned long max_delta = (1UL << 48) - 1;
struct clock_event_device *cd;
static int irq = 0, timer_irq_installed = 0;
if (!timer_irq_installed) {
irq = get_percpu_irq(INT_TI);
if (irq < 0)
pr_err("Failed to map irq %d (timer)\n", irq);
}
cd = &per_cpu(constant_clockevent_device, cpu);
cd->name = "Constant";
cd->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_PERCPU;
cd->irq = irq;
cd->rating = 320;
cd->cpumask = cpumask_of(cpu);
cd->set_state_oneshot = constant_set_state_oneshot;
cd->set_state_oneshot_stopped = constant_set_state_shutdown;
cd->set_state_periodic = constant_set_state_periodic;
cd->set_state_shutdown = constant_set_state_shutdown;
cd->set_next_event = constant_timer_next_event;
cd->event_handler = constant_event_handler;
clockevents_config_and_register(cd, const_clock_freq, min_delta, max_delta);
if (timer_irq_installed)
return 0;
timer_irq_installed = 1;
sync_counter();
if (request_irq(irq, constant_timer_interrupt, IRQF_PERCPU | IRQF_TIMER, "timer", NULL))
pr_err("Failed to request irq %d (timer)\n", irq);
lpj_fine = get_loops_per_jiffy();
pr_info("Constant clock event device register\n");
return 0;
}
static u64 read_const_counter(struct clocksource *clk)
{
return drdtime();
}
static noinstr u64 sched_clock_read(void)
{
return drdtime();
}
static struct clocksource clocksource_const = {
.name = "Constant",
.rating = 400,
.read = read_const_counter,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.vdso_clock_mode = VDSO_CLOCKMODE_CPU,
};
int __init constant_clocksource_init(void)
{
int res;
unsigned long freq = const_clock_freq;
res = clocksource_register_hz(&clocksource_const, freq);
sched_clock_register(sched_clock_read, 64, freq);
pr_info("Constant clock source device register\n");
return res;
}
void __init time_init(void)
{
if (!cpu_has_cpucfg)
const_clock_freq = cpu_clock_freq;
else
const_clock_freq = calc_const_freq();
init_offset = -(drdtime() - csr_read64(LOONGARCH_CSR_CNTC));
constant_clockevent_init();
constant_clocksource_init();
}
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