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Diffstat (limited to 'cpu/arm1176/s3c64xx/timer.c')
| -rw-r--r-- | cpu/arm1176/s3c64xx/timer.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/cpu/arm1176/s3c64xx/timer.c b/cpu/arm1176/s3c64xx/timer.c new file mode 100644 index 0000000..22a5b77 --- /dev/null +++ b/cpu/arm1176/s3c64xx/timer.c @@ -0,0 +1,177 @@ +/* + * (C) Copyright 2003 + * Texas Instruments <www.ti.com> + * + * (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 2002-2004 + * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de> + * + * (C) Copyright 2004 + * Philippe Robin, ARM Ltd. <philippe.robin@arm.com> + * + * (C) Copyright 2008 + * Guennadi Liakhovetki, DENX Software Engineering, <lg@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/proc-armv/ptrace.h> +#include <s3c6400.h> +#include <div64.h> + +static ulong timer_load_val; + +#define PRESCALER 167 + +static s3c64xx_timers *s3c64xx_get_base_timers(void) +{ + return (s3c64xx_timers *)ELFIN_TIMER_BASE; +} + +/* macro to read the 16 bit timer */ +static inline ulong read_timer(void) +{ + s3c64xx_timers *const timers = s3c64xx_get_base_timers(); + + return timers->TCNTO4; +} + +/* Internal tick units */ +/* Last decremneter snapshot */ +static unsigned long lastdec; +/* Monotonic incrementing timer */ +static unsigned long long timestamp; + +int timer_init(void) +{ + s3c64xx_timers *const timers = s3c64xx_get_base_timers(); + + /* use PWM Timer 4 because it has no output */ + /* + * We use the following scheme for the timer: + * Prescaler is hard fixed at 167, divider at 1/4. + * This gives at PCLK frequency 66MHz approx. 10us ticks + * The timer is set to wrap after 100s, at 66MHz this obviously + * happens after 10,000,000 ticks. A long variable can thus + * keep values up to 40,000s, i.e., 11 hours. This should be + * enough for most uses:-) Possible optimizations: select a + * binary-friendly frequency, e.g., 1ms / 128. Also calculate + * the prescaler automatically for other PCLK frequencies. + */ + timers->TCFG0 = PRESCALER << 8; + if (timer_load_val == 0) { + timer_load_val = get_PCLK() / PRESCALER * (100 / 4); /* 100s */ + timers->TCFG1 = (timers->TCFG1 & ~0xf0000) | 0x20000; + } + + /* load value for 10 ms timeout */ + lastdec = timers->TCNTB4 = timer_load_val; + /* auto load, manual update of Timer 4 */ + timers->TCON = (timers->TCON & ~0x00700000) | TCON_4_AUTO | + TCON_4_UPDATE; + + /* auto load, start Timer 4 */ + timers->TCON = (timers->TCON & ~0x00700000) | TCON_4_AUTO | COUNT_4_ON; + timestamp = 0; + + return 0; +} + +/* + * timer without interrupts + */ + +/* + * 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) +{ + ulong now = read_timer(); + + if (lastdec >= now) { + /* normal mode */ + timestamp += lastdec - now; + } else { + /* we have an overflow ... */ + timestamp += lastdec + timer_load_val - now; + } + lastdec = now; + + return timestamp; +} + +/* + * 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) +{ + /* We overrun in 100s */ + return (ulong)(timer_load_val / 100); +} + +void reset_timer_masked(void) +{ + /* reset time */ + lastdec = read_timer(); + timestamp = 0; +} + +void reset_timer(void) +{ + reset_timer_masked(); +} + +ulong get_timer_masked(void) +{ + unsigned long long res = get_ticks(); + do_div (res, (timer_load_val / (100 * CONFIG_SYS_HZ))); + return res; +} + +ulong get_timer(ulong base) +{ + return get_timer_masked() - base; +} + +void set_timer(ulong t) +{ + timestamp = t * (timer_load_val / (100 * CONFIG_SYS_HZ)); +} + +void udelay(unsigned long usec) +{ + unsigned long long tmp; + ulong tmo; + + tmo = (usec + 9) / 10; + tmp = get_ticks() + tmo; /* get current timestamp */ + + while (get_ticks() < tmp)/* loop till event */ + /*NOP*/; +} |