u-boot-brain/cpu/pxa/timer.c
Ingo van Lil 3eb90bad65 Generic udelay() with watchdog support
According to the PPC reference implementation the udelay() function is
responsible for resetting the watchdog timer as frequently as needed.
Most other architectures do not meet that requirement, so long-running
operations might result in a watchdog reset.

This patch adds a generic udelay() function which takes care of
resetting the watchdog before calling an architecture-specific
__udelay().

Signed-off-by: Ingo van Lil <inguin@gmx.de>
2009-12-05 01:08:53 +01:00

129 lines
2.6 KiB
C

/*
* (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>
*
* 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/arch/pxa-regs.h>
#include <div64.h>
#ifdef CONFIG_USE_IRQ
#error: interrupts not implemented yet
#endif
#if defined(CONFIG_PXA27X) || defined(CONFIG_CPU_MONAHANS)
#define TIMER_FREQ_HZ 3250000
#elif defined(CONFIG_PXA250)
#define TIMER_FREQ_HZ 3686400
#else
#error "Timer frequency unknown - please config PXA CPU type"
#endif
static inline unsigned long long tick_to_time(unsigned long long tick)
{
tick *= CONFIG_SYS_HZ;
do_div(tick, TIMER_FREQ_HZ);
return tick;
}
static inline unsigned long long us_to_tick(unsigned long long us)
{
us = us * TIMER_FREQ_HZ + 999999;
do_div(us, 1000000);
return us;
}
int timer_init (void)
{
reset_timer();
return 0;
}
void reset_timer (void)
{
reset_timer_masked ();
}
ulong get_timer (ulong base)
{
return get_timer_masked () - base;
}
void set_timer (ulong t)
{
/* nop */
}
void __udelay (unsigned long usec)
{
udelay_masked (usec);
}
void reset_timer_masked (void)
{
OSCR = 0;
}
ulong get_timer_masked (void)
{
return tick_to_time(get_ticks());
}
void udelay_masked (unsigned long usec)
{
unsigned long long tmp;
ulong tmo;
tmo = us_to_tick(usec);
tmp = get_ticks() + tmo; /* get current timestamp */
while (get_ticks() < tmp) /* loop till event */
/*NOP*/;
}
/*
* 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 OSCR;
}
/*
* 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 = TIMER_FREQ_HZ;
return tbclk;
}