diff options
Diffstat (limited to 'arch/arm/imx-common/timer.c')
| -rw-r--r-- | arch/arm/imx-common/timer.c | 149 | 
1 files changed, 149 insertions, 0 deletions
| diff --git a/arch/arm/imx-common/timer.c b/arch/arm/imx-common/timer.c new file mode 100644 index 000000000..e2725e1a6 --- /dev/null +++ b/arch/arm/imx-common/timer.c @@ -0,0 +1,149 @@ +/* + * (C) Copyright 2007 + * Sascha Hauer, Pengutronix + * + * (C) Copyright 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> + +/* General purpose timers registers */ +struct mxc_gpt { +	unsigned int control; +	unsigned int prescaler; +	unsigned int status; +	unsigned int nouse[6]; +	unsigned int counter; +}; + +static struct mxc_gpt *cur_gpt = (struct mxc_gpt *)GPT1_BASE_ADDR; + +/* 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 */ +#define CLK_32KHZ		32768		/* 32Khz input */ + +DECLARE_GLOBAL_DATA_PTR; + +#define timestamp (gd->tbl) +#define lastinc (gd->lastinc) + +static inline unsigned long long tick_to_time(unsigned long long tick) +{ +	tick *= CONFIG_SYS_HZ; +	do_div(tick, CLK_32KHZ); + +	return tick; +} + +static inline unsigned long long us_to_tick(unsigned long long usec) +{ +	usec = usec * CLK_32KHZ + 999999; +	do_div(usec, 1000000); + +	return usec; +} + +int timer_init(void) +{ +	int i; +	ulong val; + +	/* setup GP Timer 1 */ +	__raw_writel(GPTCR_SWR, &cur_gpt->control); + +	/* We have no udelay by now */ +	for (i = 0; i < 100; i++) +		__raw_writel(0, &cur_gpt->control); + +	__raw_writel(0, &cur_gpt->prescaler); /* 32Khz */ + +	/* Freerun Mode, PERCLK1 input */ +	i = __raw_readl(&cur_gpt->control); +	__raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control); + +	val = __raw_readl(&cur_gpt->counter); +	lastinc = val / (CLK_32KHZ / CONFIG_SYS_HZ); +	timestamp = 0; + +	return 0; +} + +unsigned long long get_ticks(void) +{ +	ulong now = __raw_readl(&cur_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 / CONFIG_MX25_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 CLK_32KHZ; +} |