rt-thread-official/bsp/raspberry-pi/raspi4-64/drivers/drv_gtimer.c

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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <rtthread.h>
#include "interrupt.h"
#ifndef RT_CPUS_NR
#define RT_CPUS_NR 1
#endif
#define GTIMER_IRQ (27)
static uint64_t _tickval[RT_CPUS_NR];
static uint64_t _increaseval[RT_CPUS_NR];
#define tickval _tickval[cpu_id]
#define increaseval _increaseval[cpu_id]
/**
* This function is the gtimer isr handler.
*
* @param vector interrupt ID
* @param parameter the parameter specified by rt_hw_interrupt_install
*
* @return none
*/
static void _hw_timer_isr(int vector, void *parameter)
{
#ifdef RT_USING_SMP
int cpu_id = rt_hw_cpu_id();
#else
int cpu_id = 0;
#endif
uint64_t cntvct_el0;
do
{
tickval += increaseval;
__asm__ volatile("msr CNTV_CVAL_EL0, %0"::"r"(tickval));
__asm__ volatile("mrs %0, CNTVCT_EL0":"=r"(cntvct_el0));
} while (cntvct_el0 >= tickval);
rt_tick_increase();
}
/**
* The function will initialize the general timer used for the system tick.
*
* @param none
*
* @return none
*/
rt_weak int rt_hw_gtimer_init(void)
{
#ifdef RT_USING_SMP
int cpu_id = rt_hw_cpu_id();
#else
int cpu_id = 0;
#endif
uint64_t val;
rt_hw_interrupt_install(GTIMER_IRQ, _hw_timer_isr, RT_NULL, "tick");
rt_hw_interrupt_umask(GTIMER_IRQ);
__asm__ volatile("mrs %0, CNTFRQ_EL0":"=r"(val));
increaseval = val / RT_TICK_PER_SECOND;
__asm__ volatile("msr CNTV_CTL_EL0, %0"::"r"(val));
tickval = increaseval;
__asm__ volatile("msr CNTV_CVAL_EL0, %0"::"r"(tickval));
val = 1;
__asm__ volatile("msr CNTV_CTL_EL0, %0"::"r"(val));
return 0;
}
INIT_BOARD_EXPORT(rt_hw_gtimer_init);