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 --- README | 9 +++++++++ arch/m68k/lib/time.c | 2 +- arch/powerpc/lib/interrupts.c | 2 +- drivers/timer/mpc83xx_timer.c | 2 +- 4 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/README b/README index a565748e43..ad13092bbb 100644 --- a/README +++ b/README @@ -747,6 +747,15 @@ The following options need to be configured: SoC, then define this variable and provide board specific code for the "hw_watchdog_reset" function.
+ CONFIG_SYS_WATCHDOG_FREQ + Some platforms automatically call WATCHDOG_RESET() + from the timer interrupt handler every + CONFIG_SYS_WATCHDOG_FREQ interrupts. If not set by the + board configuration file, a default of CONFIG_SYS_HZ/2 + (i.e. 500) is used. Setting CONFIG_SYS_WATCHDOG_FREQ + to 0 disables calling WATCHDOG_RESET() from the timer + interrupt. + - Real-Time Clock:
When CONFIG_CMD_DATE is selected, the type of the RTC diff --git a/arch/m68k/lib/time.c b/arch/m68k/lib/time.c index cbe29e72a8..ebb2ac54db 100644 --- a/arch/m68k/lib/time.c +++ b/arch/m68k/lib/time.c @@ -71,7 +71,7 @@ void dtimer_interrupt(void *not_used) timestamp++;
#if defined(CONFIG_WATCHDOG) || defined (CONFIG_HW_WATCHDOG) - if ((timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0) { + if (CONFIG_SYS_WATCHDOG_FREQ && (timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0) { WATCHDOG_RESET (); } #endif /* CONFIG_WATCHDOG || CONFIG_HW_WATCHDOG */ diff --git a/arch/powerpc/lib/interrupts.c b/arch/powerpc/lib/interrupts.c index 73f270002c..5ba4cd0c13 100644 --- a/arch/powerpc/lib/interrupts.c +++ b/arch/powerpc/lib/interrupts.c @@ -80,7 +80,7 @@ void timer_interrupt(struct pt_regs *regs) timestamp++;
#if defined(CONFIG_WATCHDOG) || defined (CONFIG_HW_WATCHDOG) - if ((timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0) + if (CONFIG_SYS_WATCHDOG_FREQ && (timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0) WATCHDOG_RESET (); #endif /* CONFIG_WATCHDOG || CONFIG_HW_WATCHDOG */
diff --git a/drivers/timer/mpc83xx_timer.c b/drivers/timer/mpc83xx_timer.c index 9adb4b4cab..952293195f 100644 --- a/drivers/timer/mpc83xx_timer.c +++ b/drivers/timer/mpc83xx_timer.c @@ -175,7 +175,7 @@ void timer_interrupt(struct pt_regs *regs) priv->timestamp++;
#if defined(CONFIG_WATCHDOG) || defined(CONFIG_HW_WATCHDOG) - if ((priv->timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0) + if (CONFIG_SYS_WATCHDOG_FREQ && (priv->timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0) WATCHDOG_RESET(); #endif /* CONFIG_WATCHDOG || CONFIG_HW_WATCHDOG */