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author | Wolfgang Denk <wd@denx.de> | 2009-02-01 21:38:07 +0100 |
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committer | Wolfgang Denk <wd@denx.de> | 2009-02-01 21:38:07 +0100 |
commit | 6c6e042ab3bbfb5428e4cdeb38fa27728c63afdd (patch) | |
tree | 0458ea450c3674b3d7aba64157e346f1d2553278 /cpu/arm926ejs/nomadik/timer.c | |
parent | ee924e00300bd1136589b2d5f8ad1f008df01bd4 (diff) | |
parent | 4e69087a1d6ef2eca6f46026cf5e7399b6c9e7c0 (diff) | |
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Merge branch 'master' of git://git.denx.de/u-boot-arm
Diffstat (limited to 'cpu/arm926ejs/nomadik/timer.c')
-rw-r--r-- | cpu/arm926ejs/nomadik/timer.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/cpu/arm926ejs/nomadik/timer.c b/cpu/arm926ejs/nomadik/timer.c new file mode 100644 index 0000000..2b2208c --- /dev/null +++ b/cpu/arm926ejs/nomadik/timer.c @@ -0,0 +1,183 @@ +/* + * (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 <asm/io.h> +#include <arm926ejs.h> + +#define TIMER_LOAD_VAL 0xffffffff + +/* macro to read the 32 bit timer */ +#define READ_TIMER readl(CONFIG_SYS_TIMERBASE + 20) + +static ulong timestamp; +static ulong lastdec; + +/* nothing really to do with interrupts, just starts up a counter. */ +int timer_init(void) +{ + /* Load timer with initial value */ + writel(TIMER_LOAD_VAL, CONFIG_SYS_TIMERBASE + 16); + + /* + * Set timer to be enabled, free-running, no interrupts, 256 divider, + * 32-bit, wrap-mode + */ + writel(0x8a, CONFIG_SYS_TIMERBASE + 24); + + /* 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 */ + tmo *= CONFIG_SYS_HZ; /* find number of "ticks" */ + tmo /= 1000; /* finish normalize. */ + } else { + /* small number, don't kill it prior to HZ multiply */ + tmo = usec * CONFIG_SYS_HZ; + tmo /= (1000 * 1000); + } + + tmp = get_timer(0); /* get current timestamp */ + if ((tmo + tmp + 1) < tmp) /* will roll time stamp? */ + reset_timer_masked(); /* reset to 0, set lastdec value */ + else + tmo += tmp; + + while (get_timer_masked() < tmo) + /* nothing */ ; +} + +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) */ + /* move stamp fordward */ + timestamp += lastdec - now; + } else { + /* + * An overflow is expected. + * 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 + */ + 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; + + if (usec >= 1000) { + /* if "big" number, spread normalization to seconds */ + tmo = usec / 1000; /* start to normalize */ + tmo *= CONFIG_SYS_HZ; /* find number of "ticks" */ + tmo /= 1000; /* finish normalize. */ + } else { + /* else small number, don't kill it prior to HZ multiply */ + tmo = usec * CONFIG_SYS_HZ; + tmo /= (1000*1000); + } + + reset_timer_masked(); + /* set "advancing" timestamp to 0, set lastdec vaule */ + + while (get_timer_masked() < tmo) + /* nothing */ ; +} + +/* + * 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 = CONFIG_SYS_HZ; + return tbclk; +} |