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17659d7de9
In some circumstances, reset_timer_masked() was called be timer_init() in order to perform architecture specific timer initialisation. In such cases, the required code in reset_timer_masked() has been moved into timer_init()
161 lines
4.1 KiB
C
161 lines
4.1 KiB
C
/*
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* (C) Copyright 2003
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* Texas Instruments <www.ti.com>
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*
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* (C) Copyright 2002
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* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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* Marius Groeger <mgroeger@sysgo.de>
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*
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* (C) Copyright 2002
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* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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* Alex Zuepke <azu@sysgo.de>
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*
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* (C) Copyright 2002-2004
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* Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
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*
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* (C) Copyright 2004
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* Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
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*
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* (C) Copyright 2008
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* Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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#include <asm/proc-armv/ptrace.h>
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#include <asm/arch/s3c6400.h>
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#include <div64.h>
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static ulong timer_load_val;
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#define PRESCALER 167
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static s3c64xx_timers *s3c64xx_get_base_timers(void)
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{
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return (s3c64xx_timers *)ELFIN_TIMER_BASE;
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}
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/* macro to read the 16 bit timer */
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static inline ulong read_timer(void)
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{
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s3c64xx_timers *const timers = s3c64xx_get_base_timers();
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return timers->TCNTO4;
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}
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/* Internal tick units */
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/* Last decremneter snapshot */
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static unsigned long lastdec;
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/* Monotonic incrementing timer */
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static unsigned long long timestamp;
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int timer_init(void)
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{
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s3c64xx_timers *const timers = s3c64xx_get_base_timers();
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/* use PWM Timer 4 because it has no output */
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/*
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* We use the following scheme for the timer:
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* Prescaler is hard fixed at 167, divider at 1/4.
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* This gives at PCLK frequency 66MHz approx. 10us ticks
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* The timer is set to wrap after 100s, at 66MHz this obviously
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* happens after 10,000,000 ticks. A long variable can thus
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* keep values up to 40,000s, i.e., 11 hours. This should be
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* enough for most uses:-) Possible optimizations: select a
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* binary-friendly frequency, e.g., 1ms / 128. Also calculate
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* the prescaler automatically for other PCLK frequencies.
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*/
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timers->TCFG0 = PRESCALER << 8;
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if (timer_load_val == 0) {
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timer_load_val = get_PCLK() / PRESCALER * (100 / 4); /* 100s */
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timers->TCFG1 = (timers->TCFG1 & ~0xf0000) | 0x20000;
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}
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/* load value for 10 ms timeout */
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lastdec = timers->TCNTB4 = timer_load_val;
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/* auto load, manual update of Timer 4 */
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timers->TCON = (timers->TCON & ~0x00700000) | TCON_4_AUTO |
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TCON_4_UPDATE;
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/* auto load, start Timer 4 */
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timers->TCON = (timers->TCON & ~0x00700000) | TCON_4_AUTO | COUNT_4_ON;
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timestamp = 0;
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return 0;
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}
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/*
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* timer without interrupts
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*/
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/*
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* This function is derived from PowerPC code (read timebase as long long).
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* On ARM it just returns the timer value.
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*/
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unsigned long long get_ticks(void)
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{
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ulong now = read_timer();
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if (lastdec >= now) {
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/* normal mode */
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timestamp += lastdec - now;
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} else {
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/* we have an overflow ... */
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timestamp += lastdec + timer_load_val - now;
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}
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lastdec = now;
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return timestamp;
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}
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/*
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* This function is derived from PowerPC code (timebase clock frequency).
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* On ARM it returns the number of timer ticks per second.
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*/
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ulong get_tbclk(void)
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{
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/* We overrun in 100s */
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return (ulong)(timer_load_val / 100);
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}
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ulong get_timer_masked(void)
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{
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unsigned long long res = get_ticks();
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do_div (res, (timer_load_val / (100 * CONFIG_SYS_HZ)));
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return res;
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}
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ulong get_timer(ulong base)
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{
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return get_timer_masked() - base;
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}
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void __udelay(unsigned long usec)
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{
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unsigned long long tmp;
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ulong tmo;
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tmo = (usec + 9) / 10;
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tmp = get_ticks() + tmo; /* get current timestamp */
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while (get_ticks() < tmp)/* loop till event */
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/*NOP*/;
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}
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