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/*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Alex Zuepke <azu@sysgo.de>
*
* (C) Copyright 2002
* Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
*
* (C) Copyright 2009
* Ilya Yanok, Emcraft Systems Ltd, <yanok@emcraft.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 <div64.h>
#include <asm/io.h>
#include <asm/arch/imx-regs.h>
/* General purpose timers bitfields */
#define GPTCR_SWR (1 << 15) /* Software reset */
#define GPTCR_FRR (1 << 8) /* Freerun / restart */
#define GPTCR_CLKSOURCE_32 (4 << 1) /* Clock source */
#define GPTCR_TEN 1 /* Timer enable */
static ulong timestamp;
static ulong lastinc;
/*
* "time" is measured in 1 / CONFIG_SYS_HZ seconds,
* "tick" is internal timer period
*/
#ifdef CONFIG_MX27_TIMER_HIGH_PRECISION
/* ~0.4% error - measured with stop-watch on 100s boot-delay */
static inline unsigned long long tick_to_time(unsigned long long tick)
{
tick *= CONFIG_SYS_HZ;
do_div(tick, CONFIG_MX27_CLK32);
return tick;
}
static inline unsigned long long time_to_tick(unsigned long long time)
{
time *= CONFIG_MX27_CLK32;
do_div(time, CONFIG_SYS_HZ);
return time;
}
static inline unsigned long long us_to_tick(unsigned long long us)
{
us = us * CONFIG_MX27_CLK32 + 999999;
do_div(us, 1000000);
return us;
}
#else
/* ~2% error */
#define TICK_PER_TIME ((CONFIG_MX27_CLK32 + CONFIG_SYS_HZ / 2) / \
CONFIG_SYS_HZ)
#define US_PER_TICK (1000000 / CONFIG_MX27_CLK32)
static inline unsigned long long tick_to_time(unsigned long long tick)
{
do_div(tick, TICK_PER_TIME);
return tick;
}
static inline unsigned long long time_to_tick(unsigned long long time)
{
return time * TICK_PER_TIME;
}
static inline unsigned long long us_to_tick(unsigned long long us)
{
us += US_PER_TICK - 1;
do_div(us, US_PER_TICK);
return us;
}
#endif
/* nothing really to do with interrupts, just starts up a counter. */
/* The 32768Hz 32-bit timer overruns in 131072 seconds */
int timer_init(void)
{
int i;
struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE;
struct pll_regs *pll = (struct pll_regs *)IMX_PLL_BASE;
/* setup GP Timer 1 */
writel(GPTCR_SWR, ®s->gpt_tctl);
writel(readl(&pll->pccr0) | PCCR0_GPT1_EN, &pll->pccr0);
writel(readl(&pll->pccr1) | PCCR1_PERCLK1_EN, &pll->pccr1);
for (i = 0; i < 100; i++)
writel(0, ®s->gpt_tctl); /* We have no udelay by now */
writel(0, ®s->gpt_tprer); /* 32Khz */
/* Freerun Mode, PERCLK1 input */
writel(readl(®s->gpt_tctl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR,
®s->gpt_tctl);
writel(readl(®s->gpt_tctl) | GPTCR_TEN, ®s->gpt_tctl);
return 0;
}
void reset_timer_masked(void)
{
struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE;
/* reset time */
/* capture current incrementer value time */
lastinc = readl(®s->gpt_tcn);
timestamp = 0; /* start "advancing" time stamp from 0 */
}
void reset_timer(void)
{
reset_timer_masked();
}
unsigned long long get_ticks (void)
{
struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE;
ulong now = readl(®s->gpt_tcn); /* current tick value */
if (now >= lastinc) {
/*
* normal mode (non roll)
* move stamp forward with absolut diff ticks
*/
timestamp += (now - lastinc);
} else {
/* we have rollover of incrementer */
timestamp += (0xFFFFFFFF - lastinc) + now;
}
lastinc = now;
return timestamp;
}
ulong get_timer_masked (void)
{
/*
* get_ticks() returns a long long (64 bit), it wraps in
* 2^64 / CONFIG_MX27_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
* 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in
* 5 * 10^6 days - long enough.
*/
return tick_to_time(get_ticks());
}
ulong get_timer (ulong base)
{
return get_timer_masked () - base;
}
void set_timer (ulong t)
{
timestamp = time_to_tick(t);
}
/* delay x useconds AND preserve advance timstamp value */
void __udelay (unsigned long usec)
{
unsigned long long tmp;
ulong tmo;
tmo = us_to_tick(usec);
tmp = get_ticks() + tmo; /* get current timestamp */
while (get_ticks() < tmp) /* loop till event */
/*NOP*/;
}
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