u-boot/arch/arm/mach-lpc32xx/timer.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2011 Vladimir Zapolskiy <vz@mleia.com>
 */

#include <common.h>
#include <init.h>
#include <time.h>
#include <asm/arch/cpu.h>
#include <asm/arch/clk.h>
#include <asm/arch/timer.h>
#include <asm/io.h>
#include <linux/delay.h>

static struct timer_regs  *timer0 = (struct timer_regs *)TIMER0_BASE;
static struct timer_regs  *timer1 = (struct timer_regs *)TIMER1_BASE;
static struct clk_pm_regs *clk    = (struct clk_pm_regs *)CLK_PM_BASE;

static void lpc32xx_timer_clock(u32 bit, int enable)
{
	if (enable)
		setbits_le32(&clk->timclk_ctrl1, bit);
	else
		clrbits_le32(&clk->timclk_ctrl1, bit);
}

static void lpc32xx_timer_reset(struct timer_regs *timer, u32 freq)
{
	writel(TIMER_TCR_COUNTER_RESET,   &timer->tcr);
	writel(TIMER_TCR_COUNTER_DISABLE, &timer->tcr);
	writel(0, &timer->tc);
	writel(0, &timer->pr);

	/* Count mode is every rising PCLK edge */
	writel(TIMER_CTCR_MODE_TIMER, &timer->ctcr);

	/* Set prescale counter value */
	writel((get_periph_clk_rate() / freq) - 1, &timer->pr);

	/* Ensure that the counter is not reset when matching TC */
	writel(0,  &timer->mcr);
}

static void lpc32xx_timer_count(struct timer_regs *timer, int enable)
{
	if (enable)
		writel(TIMER_TCR_COUNTER_ENABLE,  &timer->tcr);
	else
		writel(TIMER_TCR_COUNTER_DISABLE, &timer->tcr);
}

int timer_init(void)
{
	lpc32xx_timer_clock(CLK_TIMCLK_TIMER0, 1);
	lpc32xx_timer_reset(timer0, CONFIG_SYS_HZ);
	lpc32xx_timer_count(timer0, 1);

	return 0;
}

ulong get_timer(ulong base)
{
	return readl(&timer0->tc) - base;
}

void __udelay(unsigned long usec)
{
	lpc32xx_timer_clock(CLK_TIMCLK_TIMER1, 1);
	lpc32xx_timer_reset(timer1, CONFIG_SYS_HZ * 1000);
	lpc32xx_timer_count(timer1, 1);

	while (readl(&timer1->tc) < usec)
		/* NOP */;

	lpc32xx_timer_count(timer1, 0);
	lpc32xx_timer_clock(CLK_TIMCLK_TIMER1, 0);
}

unsigned long long get_ticks(void)
{
	return get_timer(0);
}

ulong get_tbclk(void)
{
	return CONFIG_SYS_HZ;
}