From 933ada560b678726835566fbff8a044fa9800175 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 14 Apr 2021 09:18:22 +0200 Subject: 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 --- README | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'README') 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 -- cgit v1.2.3