u-boot/arch/arm/cpu/arm926ejs/omap/timer.c

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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, <garyj@denx.de>
*
* (C) Copyright 2004
* Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#define TIMER_CLOCK (CONFIG_SYS_CLK_FREQ / (2 << CONFIG_SYS_PTV))
#define TIMER_LOAD_VAL 0xffffffff
/* macro to read the 32 bit timer */
#define READ_TIMER readl(CONFIG_SYS_TIMERBASE+8) \
/ (TIMER_CLOCK / CONFIG_SYS_HZ)
DECLARE_GLOBAL_DATA_PTR;
#define timestamp gd->arch.tbl
#define lastdec gd->arch.lastinc
int timer_init (void)
{
int32_t val;
/* Start the decrementer ticking down from 0xffffffff */
*((int32_t *) (CONFIG_SYS_TIMERBASE + LOAD_TIM)) = TIMER_LOAD_VAL;
val = MPUTIM_ST | MPUTIM_AR | MPUTIM_CLOCK_ENABLE | (CONFIG_SYS_PTV << MPUTIM_PTV_BIT);
*((int32_t *) (CONFIG_SYS_TIMERBASE + CNTL_TIMER)) = val;
/* init the timestamp and lastdec value */
reset_timer_masked();
return 0;
}
/*
* timer without interrupts
*/
ulong get_timer (ulong base)
{
return get_timer_masked () - base;
}
/* delay x useconds AND preserve advance timestamp 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 *= CONFIG_SYS_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 * CONFIG_SYS_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 / (TIMER_CLOCK /
CONFIG_SYS_HZ)) - 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 *= CONFIG_SYS_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 * CONFIG_SYS_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)
{
return CONFIG_SYS_HZ;
}