Re: 8xx bus monitoring

[Robin Gilks <robin.gilks@tait.co.nz>]

Pantelis Antoniou wrote:
> Robin Gilks wrote:
> 
>> Greetings
>>
>> System is a MPC859 based controller.
>>
>> I'm trying to determine whether a peripheral is not responding to 
>> memory fetches by using the bus monitor feature on the Transfer 
>> Acknowledge (TA) signal. This is set to the maximum count in the Bus 
>> Monitor Timeout (BMT) in the System Protect Control Register (SYPCR). 
>> The monitoring is enabled by setting the Bus Monitor Enable (BME) bit 
>> in SYPCR as well.
>>
>> I understand that I can use the Transfer Error Status Register (TESR) 
>> to read the fact that I have had a timeout by checking the Data 
>> Transfer Monitor Timeout (DTMT) bit in this register.
>>
>> The problem is, how do I know any error has occured so I know to look 
>> at  the TESR. I can't see a way of generating an exception from this 
>> condition.
>>
>> Any help appreciated.
>>
> 
> You get a machine check exception.
> 
> It's pretty obvious then :)
> 

Using a 2.4.22 based kernel, as far as I can see a machine check should 
be trapped (its only allowed to cause a reset in the reboot code I 
think). Assuming I got it right and it really is trapped, how come I 
always get a reset:-((

Any pointers to the code that does setup for causing an exception 
(rather than reset) would be appreciated.

-- 
Robin Gilks
Senior Design Engineer          Phone: (+64)(3) 357 1569
Tait Electronics                Fax  :  (+64)(3) 359 4632
PO Box 1645 Christchurch        Email : robin.gilks@tait.co.nz
New Zealand

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