8xx bus monitoring
Robin Gilks
robin.gilks at tait.co.nz
Mon Jan 31 09:15:45 EST 2005
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 at tait.co.nz
New Zealand
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