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/*
* Copyright (C) 2009 Samsung Electronics
* Heungjun Kim <riverful.kim@samsung.com>
* Inki Dae <inki.dae@samsung.com>
* Minkyu Kang <mk7.kang@samsung.com>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <asm/io.h>
#include <asm/arch/pwm.h>
#include <asm/arch/clk.h>
#define PRESCALER_1 (16 - 1) /* prescaler of timer 2, 3, 4 */
#define MUX_DIV_2 1 /* 1/2 period */
#define MUX_DIV_4 2 /* 1/4 period */
#define MUX_DIV_8 3 /* 1/8 period */
#define MUX_DIV_16 4 /* 1/16 period */
#define MUX4_DIV_SHIFT 16
#define TCON_TIMER4_SHIFT 20
static unsigned long count_value;
/* Internal tick units */
static unsigned long long timestamp; /* Monotonic incrementing timer */
static unsigned long lastdec; /* Last decremneter snapshot */
/* 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();
}
int timer_init(void)
{
struct s5p_timer *const timer = s5p_get_base_timer();
u32 val;
/*
* @ PWM Timer 4
* Timer Freq(HZ) =
* PWM_CLK / { (prescaler_value + 1) * (divider_value) }
*/
/* set prescaler : 16 */
/* set divider : 2 */
writel((PRESCALER_1 & 0xff) << 8, &timer->tcfg0);
writel((MUX_DIV_2 & 0xf) << MUX4_DIV_SHIFT, &timer->tcfg1);
/* count_value = 2085937.5(HZ) (per 1 sec)*/
count_value = get_pwm_clk() / ((PRESCALER_1 + 1) *
(MUX_DIV_2 + 1));
/* count_value / 100 = 20859.375(HZ) (per 10 msec) */
count_value = count_value / 100;
/* set count value */
writel(count_value, &timer->tcntb4);
lastdec = count_value;
val = (readl(&timer->tcon) & ~(0x07 << TCON_TIMER4_SHIFT)) |
TCON4_AUTO_RELOAD;
/* auto reload & manual update */
writel(val | TCON4_UPDATE, &timer->tcon);
/* start PWM timer 4 */
writel(val | TCON4_START, &timer->tcon);
timestamp = 0;
return 0;
}
/*
* timer without interrupts
*/
void reset_timer(void)
{
reset_timer_masked();
}
unsigned long get_timer(unsigned long base)
{
return get_timer_masked() - base;
}
void set_timer(unsigned long t)
{
timestamp = t;
}
/* delay x useconds */
void __udelay(unsigned long usec)
{
struct s5p_timer *const timer = s5p_get_base_timer();
unsigned long tmo, tmp;
count_value = readl(&timer->tcntb4);
if (usec >= 1000) {
/*
* if "big" number, spread normalization
* to seconds
* 1. start to normalize for usec to ticks per sec
* 2. find number of "ticks" to wait to achieve target
* 3. finish normalize.
*/
tmo = usec / 1000;
tmo *= (CONFIG_SYS_HZ * count_value / 10);
tmo /= 1000;
} else {
/* else small number, don't kill it prior to HZ multiply */
tmo = usec * CONFIG_SYS_HZ * count_value / 10;
tmo /= (1000 * 1000);
}
/* get current timestamp */
tmp = get_timer(0);
/* if setting this fordward will roll time stamp */
/* reset "advancing" timestamp to 0, set lastdec value */
/* else, set advancing stamp wake up time */
if ((tmo + tmp + 1) < tmp)
reset_timer_masked();
else
tmo += tmp;
/* loop till event */
while (get_timer_masked() < tmo)
; /* nop */
}
void reset_timer_masked(void)
{
struct s5p_timer *const timer = s5p_get_base_timer();
/* reset time */
lastdec = readl(&timer->tcnto4);
timestamp = 0;
}
unsigned long get_timer_masked(void)
{
struct s5p_timer *const timer = s5p_get_base_timer();
unsigned long now = readl(&timer->tcnto4);
if (lastdec >= now)
timestamp += lastdec - now;
else
timestamp += lastdec + count_value - now;
lastdec = now;
return timestamp;
}
/*
* 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;
}
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