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/*
* (C) Copyright 2007
* Sascha Hauer, Pengutronix
*
* (C) Copyright 2008-2009 Freescale Semiconductor, Inc.
*
* 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 <div64.h>
#include <asm/arch/imx-regs.h>
#include <asm/arch/crm_regs.h>
#include <asm/arch/clock.h>
DECLARE_GLOBAL_DATA_PTR;
#define timestamp (gd->arch.tbl)
#define lastinc (gd->arch.lastinc)
/* General purpose timers bitfields */
#define GPTCR_SWR (1<<15) /* Software reset */
#define GPTCR_FRR (1<<9) /* Freerun / restart */
#define GPTCR_CLKSOURCE_32 (4<<6) /* Clock source */
#define GPTCR_TEN (1) /* Timer enable */
/*
* "time" is measured in 1 / CONFIG_SYS_HZ seconds,
* "tick" is internal timer period
*/
/* ~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, MXC_CLK32);
return tick;
}
static inline unsigned long long us_to_tick(unsigned long long us)
{
us = us * MXC_CLK32 + 999999;
do_div(us, 1000000);
return us;
}
/*
* nothing really to do with interrupts, just starts up a counter.
* The 32KHz 32-bit timer overruns in 134217 seconds
*/
int timer_init(void)
{
int i;
struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
struct ccm_regs *ccm = (struct ccm_regs *)CCM_BASE_ADDR;
/* setup GP Timer 1 */
writel(GPTCR_SWR, &gpt->ctrl);
writel(readl(&ccm->cgr1) | 3 << MXC_CCM_CGR1_GPT_OFFSET, &ccm->cgr1);
for (i = 0; i < 100; i++)
writel(0, &gpt->ctrl); /* We have no udelay by now */
writel(0, &gpt->pre); /* prescaler = 1 */
/* Freerun Mode, 32KHz input */
writel(readl(&gpt->ctrl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR,
&gpt->ctrl);
writel(readl(&gpt->ctrl) | GPTCR_TEN, &gpt->ctrl);
return 0;
}
unsigned long long get_ticks(void)
{
struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
ulong now = readl(&gpt->counter); /* 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 / MXC_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;
}
/* 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*/;
}
/*
* This function is derived from PowerPC code (timebase clock frequency).
* On ARM it returns the number of timer ticks per second.
*/
ulong get_tbclk(void)
{
return MXC_CLK32;
}
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