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/*
* (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;
#define TIMER_ENABLE (1 << 7)
#define TIMER_MODE_MSK (1 << 6)
#define TIMER_MODE_FR (0 << 6)
#define TIMER_MODE_PD (1 << 6)
#define TIMER_INT_EN (1 << 5)
#define TIMER_PRS_MSK (3 << 2)
#define TIMER_PRS_8S (1 << 3)
#define TIMER_SIZE_MSK (1 << 2)
#define TIMER_ONE_SHT (1 << 0)
int timer_init (void)
{
ulong tmr_ctrl_val;
/* 1st disable the Timer */
tmr_ctrl_val = *(volatile ulong *)(CFG_TIMERBASE + 8);
tmr_ctrl_val &= ~TIMER_ENABLE;
*(volatile ulong *)(CFG_TIMERBASE + 8) = tmr_ctrl_val;
/*
* The Timer Control Register has one Undefined/Shouldn't Use Bit
* So we should do read/modify/write Operation
*/
/*
* Timer Mode : Free Running
* Interrupt : Disabled
* Prescale : 8 Stage, Clk/256
* Tmr Siz : 16 Bit Counter
* Tmr in Wrapping Mode
*/
tmr_ctrl_val = *(volatile ulong *)(CFG_TIMERBASE + 8);
tmr_ctrl_val &= ~(TIMER_MODE_MSK | TIMER_INT_EN | TIMER_PRS_MSK | TIMER_SIZE_MSK | TIMER_ONE_SHT );
tmr_ctrl_val |= (TIMER_ENABLE | TIMER_PRS_8S);
*(volatile ulong *)(CFG_TIMERBASE + 8) = tmr_ctrl_val;
/* 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;
}
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