[PATCH] PPC: Enable the Watchdog vector for 405

Josh Boyer jwboyer at gmail.com
Tue Oct 2 03:32:47 EST 2012

On Mon, Oct 1, 2012 at 12:25 PM, Jason Gunthorpe
<jgunthorpe at obsidianresearch.com> wrote:
> On Mon, Oct 01, 2012 at 08:16:29AM -0400, Josh Boyer wrote:
>> On Sun, Sep 30, 2012 at 7:27 PM, Jason Gunthorpe
>> <jgunthorpe at obsidianresearch.com> wrote:
>> > Move the body of the PIT exception out of line to make room.
>> What boards did you test this on?  What driver are you using for the
>> watchdog?
> Tested on a 405F6 core (Xilinx's variant), the board is custom, and
> the control for the watchdog SPRs was bundled into a watchdog driver
> for the board's watchdog controller.
>> >  /* 0x1020 - Watchdog Timer (WDT) Exception
>> >  */
>> > -#ifdef CONFIG_BOOKE_WDT
>> >         CRITICAL_EXCEPTION(0x1020, WDTException, WatchdogException)
>> > -#else
>> > -       CRITICAL_EXCEPTION(0x1020, WDTException, unknown_exception)
>> > -#endif
>> > -#endif
>> Please leave this wrapped in CONFIG_BOOKE_WDT.  I don't agree with
>> unconditionally enabling this for every 405 chip out there.
> What are you concerned with? If some core varient does not put a
> watchdog there, then you still get a panic from the default watchdog
> exception handler..

I'm concerned with the fact that you've moved PIT and now enabled
something that's been enabled for years.  There's no need to do it like

>> > -#ifdef CONFIG_BOOKE_WDT
>> > +#if defined(CONFIG_BOOKE_WDT) | defined(CONFIG_40x)
>> Pretty sure you meant || here?  Thought if you just enable the existing
>> config option, I don't think you'd need to edit this file at all.
> Yes, I didn't want to use BOOKE_WDT because I have not tested that
> driver, nor do I want that driver included in my kernel.. I think the
> watchdog driver in use should be orthogonal to having the exception
> wired in?

And it certainly can be.  Just make the driver a module and don't
install it or load it.  The #ifdef will still evaluate to true.


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