GEODE CS5535/CS5536 Watchdog Timer question

[Kushal Koolwal]

> Good discussion of these issues in the thread at:
> http://marc.info/?l=linux-kernel&m=120050717608600&w=2
I have been researching and doing trial and error (based on the above email discussion) since last couple of days to resolve my Geode Watchdog question and I would really appreciate if you can answer my simple questions (see last).

First I will provide details of my findings. 
Note: This info might be useful for people running General Software BIOS on LX/CS5536 platform to cross-check with.

Kernel: 2.6.26 git kernel
Debian Stable (etch)

Case 1:
With  CONFIG_GEODE_MFGPT_TIMER(y) and CONFIG_GEODE_WDT(m) enabled:
 - I get system hang during as noted in the above email thread.

Case 2:
Workaround based on the discussion:
With  CONFIG_GEODE_MFGPT_TIMER(y) and CONFIG_GEODE_WDT(m) enabled and mfgpt_irq=8
- The system boots fine and here is interrupt output:

dmesg:

[    0.102468] geode-mfgpt:  6 MFGPT timers available.

[    0.102549] geode-mfgpt:  Registered timer 1

[    0.102649] mfgpt-timer:  registering the MFGPT timer as a clock event.

cat /proc/interrupts
           CPU0       
  0:         26    XT-PIC-XT        timer
  1:          9    XT-PIC-XT        i8042
  2:          0    XT-PIC-XT        cascade
  3:          3    XT-PIC-XT      
  4:          3    XT-PIC-XT      
  8:       4829    XT-PIC-XT        mfgpt-timer
  9:        392    XT-PIC-XT        yenta, ehci_hcd:usb1, yenta, ohci_hcd:usb2
 11:        361    XT-PIC-XT        eth1, eth0
 12:        105    XT-PIC-XT        i8042
 14:       2178    XT-PIC-XT        ide0
NMI:          0   Non-maskable interrupts
LOC:          0   Local timer interrupts
TRM:          0   Thermal event interrupts
SPU:          0   Spurious interrupts
ERR:          0
MIS:          0

Case 3:
With just CONFIG_GEODE_WDT(m) enabled and disabling CONFIG_GEODE_MFGPT_TIMER
- system boots fine and I can use the geodewdt WATCGDOG. Here are some outputs:
dmesg:
[    0.102468] geode-mfgpt:  6 MFGPT timers available.
[    0.102549] geode-mfgpt:  Registered timer 1

cat /proc/interrupts
           CPU0       
  0:       8868    XT-PIC-XT        timer
  1:          9    XT-PIC-XT        i8042
  2:          0    XT-PIC-XT        cascade
  3:          3    XT-PIC-XT      
  4:          3    XT-PIC-XT      
  9:        350    XT-PIC-XT        ohci_hcd:usb1, ehci_hcd:usb2
 11:        172    XT-PIC-XT        eth1, eth0
 12:        105    XT-PIC-XT        i8042
 14:       2308    XT-PIC-XT        ide0
NMI:          0   Non-maskable interrupts
LOC:          0   Local timer interrupts
TRM:          0   Thermal event interrupts
SPU:          0   Spurious interrupts
ERR:          0
MIS:          0

Now my question which I had asked in my first post:

Are CONFIG_GEODE_MFGPT_TIMER and CONFIG_GEODE_WDT dependent on each other functionality wise?

Based on this email http://www.gossamer-threads.com/lists/linux/kernel/866676 it seems that we can disable CONFIG_GEODE_MFGPT_TIMER for BIOSes that are having trouble.

Will I loose some of my watchdog functionality by disabling the MFGPT timers?

I apologize for not being familiar with the watchdog territory. This is my first stab at getting the watchdog working on our boards.

Thank you for your time.

Kushal Koolwal

I do blog at http://blogs.koolwal.net/



> Date: Mon, 23 Jun 2008 23:56:52 +0100
> From: ilp at lkml.darkvoyage.org.uk
> To: kushalkoolwal at hotmail.com
> CC: linux-geode at bombadil.infradead.org
> Subject: Re: GEODE CS5535/CS5536 Watchdog Timer question
> 
> Kushal Koolwal wrote:
> > Perhaps for now I got my partial answer:
> > 
> > Enabling CONFIG_GEODE_MFGPT_TIMER causes a system hang during boot.
> 
> Good discussion of these issues in the thread at:
> http://marc.info/?l=linux-kernel&m=120050717608600&w=2
> 
> FWIW, I have both enabled, no hangs on boot and a working watchdog.
> 
> Iain

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