kern/arch/riscv/time.c

#include <arch/arch.h>
#include <arch/time.h>
#include <assert.h>
#include <ros/common.h>
#include <ros/procinfo.h>
#include <stdio.h>
#include <trap.h>

void timer_init(void)
{
	__proc_global_info.tsc_freq = TSC_HZ;
	cprintf("TSC Frequency: %llu\n", __proc_global_info.tsc_freq);
}

void set_core_timer(uint32_t usec, bool periodic)
{
	// we could implement periodic timers using one-shot timers,
	// but for now we only support one-shot
	assert(!periodic);

	if (usec) {
		uint32_t clocks = (uint64_t)usec * TSC_HZ / 1000000;

		int8_t irq_state = 0;
		disable_irqsave(&irq_state);

		mtpcr(PCR_COUNT, 0);
		mtpcr(PCR_COMPARE, clocks);
		mtpcr(PCR_SR, mfpcr(PCR_SR) | (1 << (IRQ_TIMER + SR_IM_SHIFT)));

		enable_irqsave(&irq_state);
	} else {
		mtpcr(PCR_SR,
		      mfpcr(PCR_SR) & ~(1 << (IRQ_TIMER + SR_IM_SHIFT)));
	}
}

void udelay(uint64_t usec)
{
	if (__proc_global_info.tsc_freq != 0) {
		uint64_t start, end, now;

		start = read_tsc();
		end = start + (__proc_global_info.tsc_freq * usec) / 1000000;

		do {
			cpu_relax();
			now = read_tsc();
		} while (now < end || (now > start && end < start));
	} else
		panic("udelay() was called before timer_init(), moron!");
}

uint64_t read_persistent_clock(void)
{
	return 1242129600 * 1000000000UL; /* nanwan's birthday */
}