[U-Boot] [PATCH] at91: Don't initialize watchdog if CONFIG_SYS_WDTC_WDMR_VAL is undefined

[Wolfgang Denk]

Dear Alexander Stein,

In message <201007220817.17441.alexander.stein at systec-electronic.com> you wrote:
> 
> > This seems the wrong approach to me - when CONFIG_HW_WATCHDOG is
> > defined and requires CONFIG_SYS_WDTC_WDMR_VAL, but the latter is
> > missing, than this should raise n error condition. We must not
> > silently ignore errors.
> 
> Well, my problem is, that CONFIG_SYS_WDTC_WDMR_VAL is used to program the 
> internal watchdog. But this watchdog can only be programmed once until a reset 
> occurs. So there is no possibility for linux to reprogram it.

This is normal. Any watchdog that is worth the name will behave
similar.

> So, if CONFIG_SYS_WDTC_WDMR_VAL is not defined and the watchdog is not 
> programed using my patch, the watchdog still runs with default settings 
> (timeout of 16s). So a user may choose to trigger the watchdog from u-boot 
> (define CONFIG_AT91SAM9_WATCHDOG and CONFIG_HW_WATCHDOG) or let it run 
> silently. To summarize, CONFIG_SYS_WDTC_WDMR_VAL is not needed to use 
> CONFIG_AT91SAM9_WATCHDOG and CONFIG_HW_WATCHDOG.

Then the subject is misleading - it suggests you do not initialize /
let run the watchdog at all if CONFIG_SYS_WDTC_WDMR_VAL is undefined.


I think we should make sure that everything is in a sane and
consistent state - if CONFIG_HW_WATCHDOG (and
CONFIG_AT91SAM9_WATCHDOG) are set, this indicates that U-Boot is
supposed to use the watchdog, which in turn means they should
initialize it.

Best regards,

Wolfgang Denk

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