rt-thread-official/libcpu/risc-v/t-head/c906/tick.c

70 lines
1.4 KiB
C

/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2018/10/28 Bernard The unify RISC-V porting code.
*/
#include <rthw.h>
#include <rtthread.h>
#include <encoding.h>
#include "sbi.h"
#include "tick.h"
static volatile uint64_t time_elapsed = 0;
static volatile unsigned long tick_cycles = 0;
static unsigned long tick_delta = TIMER_CLK_FREQ / RT_TICK_PER_SECOND;
static uint64_t get_ticks()
{
__asm__ __volatile__(
"rdtime %0"
: "=r"(time_elapsed));
return time_elapsed;
}
int tick_isr(void)
{
rt_tick_increase();
sbi_set_timer(get_ticks() + tick_delta);
return 0;
}
/* Sets and enable the timer interrupt */
int rt_hw_tick_init(void)
{
/* Clear the Supervisor-Timer bit in SIE */
clear_csr(sie, SIP_STIP);
/* Set timer */
sbi_set_timer(get_ticks() + tick_delta);
/* Enable the Supervisor-Timer bit in SIE */
set_csr(sie, SIP_STIP);
return 0;
}
/**
* This function will delay for some us.
*
* @param us the delay time of us
*/
void rt_hw_us_delay(rt_uint32_t us)
{
unsigned long start_time;
unsigned long end_time;
unsigned long run_time;
start_time = get_ticks();
end_time = start_time + us * (TIMER_CLK_FREQ / 1000000);
do
{
run_time = get_ticks();
} while(run_time < end_time);
}