u-boot/arch/arm/cpu/arm926ejs/lpc32xx/timer.c
Gregory CLEMENT c8aac24629 arm: lpc32xx: Fix timer initialization
The match controller register is not cleared during
initialization. However, some bits of this register may reset the TC if
tnMRx match it.

As we can't make any assumption about how U-Boot is launched by the first
stage bootloader (such as S1L) clearing this register ensure that the
timers work as expected.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2019-04-26 18:58:20 -04:00

84 lines
1.9 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2011 Vladimir Zapolskiy <vz@mleia.com>
*/
#include <common.h>
#include <asm/arch/cpu.h>
#include <asm/arch/clk.h>
#include <asm/arch/timer.h>
#include <asm/io.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;
}