uboot/u-boot-stm32mp-2020.01/arch/arm/cpu/armv7/s5p-common/timer.c

137 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2009 Samsung Electronics
* Heungjun Kim <riverful.kim@samsung.com>
* Inki Dae <inki.dae@samsung.com>
* Minkyu Kang <mk7.kang@samsung.com>
*/
#include <common.h>
#include <div64.h>
#include <time.h>
#include <asm/io.h>
#include <asm/arch/pwm.h>
#include <asm/arch/clk.h>
/* Use the old PWM interface for now */
#undef CONFIG_DM_PWM
#include <pwm.h>
DECLARE_GLOBAL_DATA_PTR;
unsigned long get_current_tick(void);
static void reset_timer_masked(void);
/* macro to read the 16 bit timer */
static inline struct s5p_timer *s5p_get_base_timer(void)
{
return (struct s5p_timer *)samsung_get_base_timer();
}
/**
* Read the countdown timer.
*
* This operates at 1MHz and counts downwards. It will wrap about every
* hour (2^32 microseconds).
*
* @return current value of timer
*/
static unsigned long timer_get_us_down(void)
{
struct s5p_timer *const timer = s5p_get_base_timer();
return readl(&timer->tcnto4);
}
int timer_init(void)
{
/* PWM Timer 4 */
pwm_init(4, MUX_DIV_4, 0);
pwm_config(4, 100000, 100000);
pwm_enable(4);
/* Use this as the current monotonic time in us */
gd->arch.timer_reset_value = 0;
/* Use this as the last timer value we saw */
gd->arch.lastinc = timer_get_us_down();
reset_timer_masked();
return 0;
}
/*
* timer without interrupts
*/
unsigned long get_timer(unsigned long base)
{
unsigned long long time_ms;
ulong now = timer_get_us_down();
/*
* Increment the time by the amount elapsed since the last read.
* The timer may have wrapped around, but it makes no difference to
* our arithmetic here.
*/
gd->arch.timer_reset_value += gd->arch.lastinc - now;
gd->arch.lastinc = now;
/* Divide by 1000 to convert from us to ms */
time_ms = gd->arch.timer_reset_value;
do_div(time_ms, 1000);
return time_ms - base;
}
unsigned long __attribute__((no_instrument_function)) timer_get_us(void)
{
static unsigned long base_time_us;
struct s5p_timer *const timer =
(struct s5p_timer *)samsung_get_base_timer();
unsigned long now_downward_us = readl(&timer->tcnto4);
if (!base_time_us)
base_time_us = now_downward_us;
/* Note that this timer counts downward. */
return base_time_us - now_downward_us;
}
/* delay x useconds */
void __udelay(unsigned long usec)
{
unsigned long count_value;
count_value = timer_get_us_down();
while ((int)(count_value - timer_get_us_down()) < (int)usec)
;
}
static void reset_timer_masked(void)
{
struct s5p_timer *const timer = s5p_get_base_timer();
/* reset time */
gd->arch.lastinc = readl(&timer->tcnto4);
gd->arch.tbl = 0;
}
/*
* This function is derived from PowerPC code (read timebase as long long).
* On ARM it just returns the timer value.
*/
unsigned long long get_ticks(void)
{
return get_timer(0);
}
/*
* This function is derived from PowerPC code (timebase clock frequency).
* On ARM it returns the number of timer ticks per second.
*/
unsigned long get_tbclk(void)
{
return CONFIG_SYS_HZ;
}