u-boot/arch/powerpc/lib/interrupts.c
Rasmus Villemoes 933ada560b allow opting out of WATCHDOG_RESET() from timer interrupt
Having WATCHDOG_RESET() called automatically from the timer interrupt
runs counter to the idea of a watchdog device - if the board runs into
an infinite loops with interrupts still enabled, the watchdog will
never fire.

When using CONFIG_(SPL_)WDT, the watchdog_reset function is a lot more
complicated than just poking a few SOC-specific registers - it
involves accessing all kinds of global data, and if the interrupt
happens at the wrong time (say, in the middle of an WATCHDOG_RESET()
call from ordinary code), that can end up corrupting said global data.

Allow the board to opt out of calling WATCHDOG_RESET() from the timer
interrupt handler by setting CONFIG_SYS_WATCHDOG_FREQ to 0 - as that
setting is currently nonsensical (it would be compile-time
divide-by-zero), it cannot affect any existing boards.

Add documentation for both the existing and extended meaning of
CONFIG_SYS_WATCHDOG_FREQ.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
2021-04-27 08:28:07 +02:00

96 lines
1.9 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2000-2002
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* (C) Copyright 2003
* Gleb Natapov <gnatapov@mrv.com>
*/
#include <common.h>
#include <irq_func.h>
#include <asm/processor.h>
#include <watchdog.h>
#ifdef CONFIG_LED_STATUS
#include <status_led.h>
#endif
#include <asm/ptrace.h>
#ifndef CONFIG_MPC83XX_TIMER
#ifndef CONFIG_SYS_WATCHDOG_FREQ
#define CONFIG_SYS_WATCHDOG_FREQ (CONFIG_SYS_HZ / 2)
#endif
static unsigned decrementer_count; /* count value for 1e6/HZ microseconds */
static __inline__ unsigned long get_dec (void)
{
unsigned long val;
asm volatile ("mfdec %0":"=r" (val):);
return val;
}
static __inline__ void set_dec (unsigned long val)
{
if (val)
asm volatile ("mtdec %0"::"r" (val));
}
#endif /* !CONFIG_MPC83XX_TIMER */
void enable_interrupts(void)
{
set_msr (get_msr () | MSR_EE);
}
/* returns flag if MSR_EE was set before */
int disable_interrupts(void)
{
ulong msr = get_msr ();
set_msr (msr & ~MSR_EE);
return ((msr & MSR_EE) != 0);
}
#ifndef CONFIG_MPC83XX_TIMER
int interrupt_init(void)
{
/* call cpu specific function from $(CPU)/interrupts.c */
interrupt_init_cpu (&decrementer_count);
set_dec (decrementer_count);
set_msr (get_msr () | MSR_EE);
return (0);
}
static volatile ulong timestamp = 0;
void timer_interrupt(struct pt_regs *regs)
{
/* call cpu specific function from $(CPU)/interrupts.c */
timer_interrupt_cpu (regs);
/* Restore Decrementer Count */
set_dec (decrementer_count);
timestamp++;
#if defined(CONFIG_WATCHDOG) || defined (CONFIG_HW_WATCHDOG)
if (CONFIG_SYS_WATCHDOG_FREQ && (timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0)
WATCHDOG_RESET ();
#endif /* CONFIG_WATCHDOG || CONFIG_HW_WATCHDOG */
#ifdef CONFIG_LED_STATUS
status_led_tick(timestamp);
#endif /* CONFIG_LED_STATUS */
}
ulong get_timer (ulong base)
{
return (timestamp - base);
}
#endif /* !CONFIG_MPC83XX_TIMER */