Messages in this thread | | | Subject | Re: [PATCH v3] watchdog: Add watchdog timer support for the WinSystems EBC-C384 | From | Guenter Roeck <> | Date | Wed, 27 Jan 2016 17:51:50 -0800 |
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On 01/27/2016 04:18 PM, William Breathitt Gray wrote: > On Tue, Jan 26, 2016 at 09:02:45PM -0800, Guenter Roeck wrote: >>> Unfortunately, the sensors-detect only reported "No" for each Super I/O >>> chip test, while the superiotool gave an unhelpful "No Super I/O chip >>> detected" message. >>> >> >> Too bad. That suggests that the watchdog may in fact be implemented in the fpga. > > I received a response from WinSystems: the watchdog timer is implemented > in the Lattice FPGA (base address 0x298), along with other WinSystems > firmware. I was offered two methods of identifying the chip. > > The first method is to use a 16-bit read of the register at port address > 0x29E to get the version number of the watchdog timer; my machine > reported a value of 0x0009. Unfortunately, I don't believe this method > is very reliable since the version number may not be consistent across > these motherboards, and the same value could easily happen to be > returned by an unknown hardware. > > The second method is slightly more involved so I'll quote WinSystems: > >> 8-bit read of 299h – save this value >> 8-bit write of 60h to 299h >> 16-bit read of 29ah should return the base address of the WDT which is 564h >> 8-bit write of saved value to 299h - don’t want t accidentally change the WDT base address > > If the system does return a value of 0x564, then it's pretty safe to say > that the watchdog timer is implemented on the chip. However, I'm not > sure it would be safe to send write commands to a port address until the > hardware has been identified; this second method may not be the best > route either. > > What do you think? > Let's stick with DMI.
Thanks, Guenter
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