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Dockstar watchdog supported?

Posted by astker 
Dockstar watchdog supported?
May 26, 2012 09:27PM
Watchdog was mentioned in a post by restamp at http://forum.doozan.com/read.php?3,6965,7566#msg-7566, can someone please confirm whether dockstar have watchdog? Is watchdog supported in emDebian or davygravy's Debian 3.3.2 kernel? How do I enable watchdog?

Thanks
Re: Dockstar watchdog supported?
May 26, 2012 11:52PM
astker, I think the hardware watchdog timer is integral to the Marvel chipset, at least the 88f5182 and 88f6281 architectures. Whether the Debian kernel uses it is anyone's guess.

The details of the timer can be found in this document:

http://www.marvell.com/embedded-processors/kirkwood/assets/FS_88F6180_9x_6281_OpenSource.pdf

Start reading around page 283.

Frankly, when I was playing around with this on my SheevaPlug in 2009, I was concerned about a kernel panic occurring which would lock up the machine. I wanted to ensure a panic would result in a reboot instead of a hang, so I cobbled together a user level program to activate it using /dev/mem. If you want to take a look at my program, see:

http://cboh.org/SheevaPlug/hw-wdt.c

Note that the way the timer registers are accessed is really a kludge. Ideally, the watchdog should be accessible from a special device via ioctls, or perhaps from the /proc file system. The idea of controlling the watchdog from a user process is good, though, as it will detect a user-level lockout where the kernel is still functional.

It is unlikely (but not out of the question) that the timer control registers are located in the same location in the Debian/Dockstar /dev/mem address space today that they were in the original Ubuntu/SheevaPlug circa 2009, so the program might require some changes to make it functional again today. And, in any event, today's kernels seem to be fairly solid. I'm simply not seeing any panics, like I occasionally did with the early Ubuntu kernels, so perhaps this is overkill. Whatever, I haven't bothered to port it to my Dockstar or Pogoplug machines.

This is probably not the answer you were looking for, but I hope it is a starting point if you are interested in pursuing it.
dpffan
Re: Dockstar watchdog supported?
May 29, 2012 07:05AM
mach-kirkwood's common.c
303 /*****************************************************************************
304  * Watchdog
305  ****************************************************************************/
306 void __init kirkwood_wdt_init(void)
307 {
308         orion_wdt_init(kirkwood_tclk);
309 }
310 
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