calling bios interrupt

calling bios interrupt

[Jozef Kutej]

Hello.

Can someone help me solve my problem with on board watch dog timer that 
need to call bios interrupt? Here's how to update watch dog timer.

mov ax,6f02h
mov bl, 30	;number of seconds
int 15h

How can i do this in kernel so that i can write wdt driver?

Thank you.

Jozef Kutej.

Re: calling bios interrupt

[Alan Cox]

On Iau, 2006-02-02 at 08:48 +0100, Jozef Kutej wrote:
> Hello.
> 
> Can someone help me solve my problem with on board watch dog timer that 
> need to call bios interrupt? Here's how to update watch dog timer.
> 
> mov ax,6f02h
> mov bl, 30	;number of seconds
> int 15h
> 
> How can i do this in kernel so that i can write wdt driver?

You need to drive the hardware directly. Ask the vendor for the hardware
info, or alternatively you might want to try using a library like lrmi
in user space to call it and log the I/O instructions it tries to
execute.

Re: calling bios interrupt

[linux-os (Dick Johnson)]

On Thu, 2 Feb 2006, Alan Cox wrote:

> On Iau, 2006-02-02 at 08:48 +0100, Jozef Kutej wrote:
>> Hello.
>>
>> Can someone help me solve my problem with on board watch dog timer that
>> need to call bios interrupt? Here's how to update watch dog timer.
>>
>> mov ax,6f02h
>> mov bl, 30	;number of seconds
>> int 15h
>>
>> How can i do this in kernel so that i can write wdt driver?
>
> You need to drive the hardware directly. Ask the vendor for the hardware
> info, or alternatively you might want to try using a library like lrmi
> in user space to call it and log the I/O instructions it tries to
> execute.
>

Also, if the machine has a floppy, boot DOS. Write the above snippit
of code using DOS debug. Step through it. Watch what register(s) get
written...

A>debug
- a100
- mov ax,6f02
- mov bl, ff
- int 15
- int 3

rip 100
- t ; trace the steps.

Once the timer gets written, the machine will reboot when it
times-out. Therefore use a large timeout value as above 0xff.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.13.4 on an i686 machine (5589.66 BogoMips).
Warning : 98.36% of all statistics are fiction.
_
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Thank you.

Re: calling bios interrupt

[Vishal Soni]

On 2/2/06, Jozef Kutej <jozef.kutej@slovanet.net> wrote:
> Hello.
>
> Can someone help me solve my problem with on board watch dog timer that
> need to call bios interrupt? Here's how to update watch dog timer.
>
> mov ax,6f02h
> mov bl, 30      ;number of seconds
> int 15h
>
> How can i do this in kernel so that i can write wdt driver?
>
> Thank you.
CMIIW, is it not that for using BIOS interrupt one has to do the same
by entering in real mode or else real mode interrupt handler, would be
replaced with an appropriate exception handler by Linux.
check this : http://www.mega-tokyo.com/forum/index.php?board=1;action=display;threadid=8997;start=0#msg77808

like when i try to use int 10h in one of my kernel modules and try to
insert it with insmod i get Floating Point Exception.

And one has to use vm86() system call and save the register context as
given in below url to achieve the results.
http://x86.ddj.com/articles/pmbasics/tspec_a1_doc.htm
>
> Jozef Kutej.
> -