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Diffstat (limited to 'cpu/arm926ejs/versatile/timer.c')
| -rw-r--r-- | cpu/arm926ejs/versatile/timer.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/cpu/arm926ejs/versatile/timer.c b/cpu/arm926ejs/versatile/timer.c new file mode 100644 index 000000000..32872d2b6 --- /dev/null +++ b/cpu/arm926ejs/versatile/timer.c @@ -0,0 +1,175 @@ +/* + * (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, <gj@denx.de> + * + * (C) Copyright 2004 + * Philippe Robin, ARM Ltd. <philippe.robin@arm.com> + * + * 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 <arm926ejs.h> + +#define TIMER_LOAD_VAL 0xffffffff + +/* macro to read the 32 bit timer */ +#define READ_TIMER (*(volatile ulong *)(CFG_TIMERBASE+4)) + +static ulong timestamp; +static ulong lastdec; + +/* nothing really to do with interrupts, just starts up a counter. */ +int timer_init (void) +{ + *(volatile ulong *)(CFG_TIMERBASE + 0) = CFG_TIMER_RELOAD; /* TimerLoad */ + *(volatile ulong *)(CFG_TIMERBASE + 4) = CFG_TIMER_RELOAD; /* TimerValue */ + *(volatile ulong *)(CFG_TIMERBASE + 8) = 0x8C; + + /* init the timestamp and lastdec value */ + reset_timer_masked(); + + 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 AND perserve advance timstamp value */ +void udelay (unsigned long usec) +{ + ulong tmo, tmp; + + if(usec >= 1000){ /* if "big" number, spread normalization to seconds */ + tmo = usec / 1000; /* start to normalize for usec to ticks per sec */ + tmo *= CFG_HZ; /* find number of "ticks" to wait to achieve target */ + tmo /= 1000; /* finish normalize. */ + }else{ /* else small number, don't kill it prior to HZ multiply */ + tmo = usec * CFG_HZ; + tmo /= (1000*1000); + } + + tmp = get_timer (0); /* get current timestamp */ + if( (tmo + tmp + 1) < tmp ) /* if setting this fordward will roll time stamp */ + reset_timer_masked (); /* reset "advancing" timestamp to 0, set lastdec value */ + else + tmo += tmp; /* else, set advancing stamp wake up time */ + + while (get_timer_masked () < tmo)/* loop till event */ + /*NOP*/; +} + +void reset_timer_masked (void) +{ + /* reset time */ + lastdec = READ_TIMER; /* capure current decrementer value time */ + timestamp = 0; /* start "advancing" time stamp from 0 */ +} + +ulong get_timer_masked (void) +{ + ulong now = READ_TIMER; /* current tick value */ + + if (lastdec >= now) { /* normal mode (non roll) */ + /* normal mode */ + timestamp += lastdec - now; /* move stamp fordward with absoulte diff ticks */ + } else { /* we have overflow of the count down timer */ + /* nts = ts + ld + (TLV - now) + * ts=old stamp, ld=time that passed before passing through -1 + * (TLV-now) amount of time after passing though -1 + * nts = new "advancing time stamp"...it could also roll and cause problems. + */ + timestamp += lastdec + TIMER_LOAD_VAL - now; + } + lastdec = now; + + return timestamp; +} + +/* waits specified delay value and resets timestamp */ +void udelay_masked (unsigned long usec) +{ + ulong tmo; + ulong endtime; + signed long diff; + + if (usec >= 1000) { /* if "big" number, spread normalization to seconds */ + tmo = usec / 1000; /* start to normalize for usec to ticks per sec */ + tmo *= CFG_HZ; /* find number of "ticks" to wait to achieve target */ + tmo /= 1000; /* finish normalize. */ + } else { /* else small number, don't kill it prior to HZ multiply */ + tmo = usec * CFG_HZ; + tmo /= (1000*1000); + } + + endtime = get_timer_masked () + tmo; + + do { + ulong now = get_timer_masked (); + diff = endtime - now; + } while (diff >= 0); +} + +/* + * 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) +{ + ulong tbclk; + + tbclk = CFG_HZ; + return tbclk; +} |