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/*
* (C) Copyright 2004
* Texas Instruments <www.ti.com>
* Jian Zhang <jzhang@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
* Gary Jennejohn, DENX Software Engineering, <gj@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>
#define TIMER_LOAD_VAL 0xffffffff
/* macro to read the 32 bit timer */
#define READ_TIMER (*(volatile ulong *)(CFG_TIMERBASE+8))
static ulong timestamp;
static ulong lastdec;
static void reset_timer_masked (void);
/* nothing really to do with cpu, just starts up a counter. */
int cpu_init (void)
{
int32_t val;
/* Start the decrementer ticking down from 0xffffffff */
*((int32_t *) (CFG_TIMERBASE + LOAD_TIM)) = TIMER_LOAD_VAL;
val = MPUTIM_ST | MPUTIM_AR | MPUTIM_CLOCK_ENABLE | (CFG_PVT << MPUTIM_PTV_BIT);
*((int32_t *) (CFG_TIMERBASE + CNTL_TIMER)) = val;
/* init the timestamp and lastdec value */
reset_timer_masked();
return (0);
}
static void reset_timer_masked (void)
{
/* reset time */
lastdec = READ_TIMER; /* capure current decrementer value time */
timestamp = 0; /* start "advancing" time stamp from 0 */
}
#ifdef CFG_UDELAY
static ulong get_timer_masked (void);
static ulong get_timer (ulong base);
/* 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) < 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*/;
}
static 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;
}
static ulong get_timer (ulong base)
{
return get_timer_masked () - base;
}
#endif /* CFG_UDELAY */
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