[U-Boot] mcf5445x watchdog support in U-Boot

From: Matthew Lear <matt@bubblegen.co.uk>
To: u-boot@lists.denx.de
Subject: [U-Boot] mcf5445x watchdog support in U-Boot
Date: Thu, 18 Jun 2009 14:40:14 +0100	[thread overview]
Message-ID: <a646eb1edd6dc97da36aa184cb8d67a4.squirrel@webmail.plus.net> (raw)
In-Reply-To: <4791E710007FEB4BBF83775D787F462F08A83E55@az33exm22.fsl.freescale.net>

Hi TsiChung,

I can supply you my patch for a watchdog driver implementation for 5445x
to test with if you like? I've not fed it back to Freescale yet. Will do
though. It's based on 2.6.29.

Is there a mechanism to allow U-Boot to indicate to Linux that it has
enabled the watchdog (eg as part of the bd_info struct maybe)? Just a
thought... It could then be kicked at kernel arch init and then repeatedly
by Linux user space via /dev/watchdog if required by the application. The
reason I suggested kicking the watchdog in arch init is to give Linux a
chance to boot (kernel and user) before the watchdog times out. Obviously
several things could prevent this (eg tasks that take time before user
space starts for example fsck etc).

I'm sure other U-Boot developers/maintainers have thought about this..?
Thoughts?

In any case, I need to enable the watchdog in U-Boot for a mcf54451 based
platform because need it in our system (we're using an mcf54455 evb as
reference hw). I'm happy to help in the development / testing etc. Please
just let me know.

Best regards,
--  Matt

> Matt,
>
> Yes. I am planning to enable watchdog in mcf5445x in u-boot. Need to
> investigate more in booting linux and the transition to starting the
> linux kernel of watchdog behavior to make sure it is not causing problem
> to the linux kernel.
>
> Best Regards,
> TsiChung
>
>
> -----Original Message-----
> From: Matthew Lear [mailto:matt at bubblegen.co.uk]
> Sent: Monday, June 15, 2009 7:59 AM
> To: Liew Tsi Chung-R5AAHP; u-boot at lists.denx.de
> Subject: mcf5445x watchdog support in U-Boot
>
> Hi TsiChung et al,
>
> I was wondering if there are plans to support and utilise the watchdog
> in the mcf5445x devices within U-Boot?
>
> I've ported a kernel driver from the bitshrine gpp
> (http://www.bitshrine.org/gpp/linux-2.6.25-mcfv4e-watchdog.patch) so
> that it hooks into my 54455 hw (Freescale EVB), however I'd like to
> configure and enable the watchdog in U-Boot with the intention that once
> Linux starts, the responsibility of kicking the watchdog resides with a
> user space app -> driver.
>
> Thoughts?
>
> Much appreciated.
> --  Matt
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