[U-Boot] Watchdog support for ppc4xx

[Mark Maestas]

Thanks Stefan, 

I actually determined that after the git repository build did the same
thing.  I changed it to use the SPRN_TCR and SPRN_TSR values but I did
see in processor.h where TSR and TCR are defined so I will modify it
based on those values.  The watchdog reset notification is very useful
and we have done that with red boot on a different project so I will
make an attempt to implement the same functionality.  Basically you need
to detect if the watchdog did force a reset and ideally how long the
system was running before it reset to determine which partition to boot
in a dual partition setup.  

Thanks for the quick response.  I will work to create a patch for this
functionality according to the u-boot standards.

Mark


-----Original Message-----
From: Stefan Roese [mailto:sr at denx.de] 
Sent: Thursday, May 20, 2010 4:55 AM
To: u-boot at lists.denx.de
Cc: Mark Maestas
Subject: Re: [U-Boot] Watchdog support for ppc4xx

Hi Mark,

On Thursday 20 May 2010 00:27:50 Mark Maestas wrote:
> I have a question about watchdog support for PPC_4xx.  When I define
> CONFIG_WATCHDOG in canyonlands.h, I get an error when building
> cpu_init.c.  The error code reads:
> 
> {standard input}: Assembler messages:
> {standard input}:133: Error: unsupported relocation against tcr
> {standard input}:141: Error: unsupported relocation against tcr
> {standard input}:146: Error: unsupported relocation against tsr
> {standard input}:154: Error: unsupported relocation against tsr
> make[1]: *** [cpu_init.o] Error 1
> 
> Shouldn't this work?

It *should*. But unfortunately it doesn't. I just checked this here
myself. I 
get the same error. Seems that the "tcr/tsr" defines need to be
converted to 
upper-case. It would be great if you could send a patch for this.

> Also I would like to determine in u-boot if a
> reset was caused by the watchdog timer using the TSR WRS field.  If it
> was reset by the watchdog we will boot into a failsafe partition to
> protect against system update errors.
> 
> Has anyone done something like this?

Such a detection is not implemented for PPC4xx. Not sure if it's
implemented 
for any other architecture.

Cheers,
Stefan

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