[U-Boot] Watchdog support.

[Wolfgang Denk]

Dear "Luigi 'Comio' Mantellini",

In message <200809141313.51807.luigi.mantellini at idf-hit.com> you wrote:
> 
> Anyway, I'm not sure that the common infrastructure covers all scenarios. For 
> example in /common/main.c we have the code:

As menrioned before, I'm not so sure about the MIPS implementation,
but this is in proiduction use in several PowerPC boards.

> int readline_into_buffer (const char *const prompt, char * buffer)
> {
> ...

> if I enable CONFIG_BOOT_RETRY_TIME or CONFIG_SHOW_ACTIVITY the while loops
> iterate a call to tstc() to check the presence of a char in the input buffer. 
> If tstc doesn't reset the watchdog (like ns16550 driver in my case) we could 
> have a watchdog timeout.

He. I see what you mean. Well, U-Boot makes no attempts (yet) to
implement actual watchdog checking for the U-Boot code itself. We
just make sure that the watchdog gets triggered. This is done in the
timer interrupt; see "lib_ppc/interrupts.c":

116 void timer_interrupt (struct pt_regs *regs)
117 {
...
126 #if defined(CONFIG_WATCHDOG) || defined (CONFIG_HW_WATCHDOG)
127         if ((timestamp % (CFG_WATCHDOG_FREQ)) == 0)
128                 WATCHDOG_RESET ();
129 #endif    /* CONFIG_WATCHDOG || CONFIG_HW_WATCHDOG */

So specific watchdog triggering is only necessary for those parts  of
the code that have to be run with interrupts switched off.

> Ok I patched the serial line driver in order to call the WATCHDOG_RESET 
> function... but I will not cover all code flows.

That should not be necessary.


Best regards,

Wolfgang Denk

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