diff options
Diffstat (limited to 'arch/arm/cpu/armv7/omap-common/timer.c')
| -rw-r--r-- | arch/arm/cpu/armv7/omap-common/timer.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/omap-common/timer.c b/arch/arm/cpu/armv7/omap-common/timer.c new file mode 100644 index 0000000..69e285f --- /dev/null +++ b/arch/arm/cpu/armv7/omap-common/timer.c @@ -0,0 +1,143 @@ +/* + * (C) Copyright 2008 + * Texas Instruments + * + * Richard Woodruff <r-woodruff2@ti.com> + * Syed Moahmmed Khasim <khasim@ti.com> + * + * (C) Copyright 2002 + * Sysgo Real-Time Solutions, GmbH <www.elinos.com> + * Marius Groeger <mgroeger@sysgo.de> + * Alex Zuepke <azu@sysgo.de> + * + * (C) Copyright 2002 + * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de> + * + * 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> + +static ulong timestamp; +static ulong lastinc; +static struct gptimer *timer_base = (struct gptimer *)CONFIG_SYS_TIMERBASE; + +/* + * Nothing really to do with interrupts, just starts up a counter. + * We run the counter with 13MHz, divided by 8, resulting in timer + * frequency of 1.625MHz. With 32bit counter register, counter + * overflows in ~44min + */ + +/* 13MHz / 8 = 1.625MHz */ +#define TIMER_CLOCK (V_SCLK / (2 << CONFIG_SYS_PTV)) +#define TIMER_LOAD_VAL 0xffffffff + +int timer_init(void) +{ + /* start the counter ticking up, reload value on overflow */ + writel(TIMER_LOAD_VAL, &timer_base->tldr); + /* enable timer */ + writel((CONFIG_SYS_PTV << 2) | TCLR_PRE | TCLR_AR | TCLR_ST, + &timer_base->tclr); + + reset_timer_masked(); /* init the timestamp and lastinc value */ + + return 0; +} + +/* + * timer without interrupts + */ +void reset_timer(void) +{ + reset_timer_masked(); +} + +ulong get_timer(ulong base) +{ + return get_timer_masked() - base; +} + +void set_timer(ulong t) +{ + timestamp = t; +} + +/* delay x useconds */ +void __udelay(unsigned long usec) +{ +#if defined(CONFIG_OMAP44XX) + /* TODO temporary hack until OMAP4 clock setup routines are present */ + if (usec > 1000) + usec = usec/1000; +#endif + long tmo = usec * (TIMER_CLOCK / 1000) / 1000; + unsigned long now, last = readl(&timer_base->tcrr); + + while (tmo > 0) { + now = readl(&timer_base->tcrr); + if (last > now) /* count up timer overflow */ + tmo -= TIMER_LOAD_VAL - last + now; + else + tmo -= now - last; + last = now; + } +} + +void reset_timer_masked(void) +{ + /* reset time, capture current incrementer value time */ + lastinc = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ); + timestamp = 0; /* start "advancing" time stamp from 0 */ +} + +ulong get_timer_masked(void) +{ + /* current tick value */ + ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ); + + if (now >= lastinc) /* normal mode (non roll) */ + /* move stamp fordward with absoulte diff ticks */ + timestamp += (now - lastinc); + else /* we have rollover of incrementer */ + timestamp += ((TIMER_LOAD_VAL / (TIMER_CLOCK / CONFIG_SYS_HZ)) + - lastinc) + now; + lastinc = 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. + */ +ulong get_tbclk(void) +{ + return CONFIG_SYS_HZ; +} |