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

This email, including any attachments, is only for the intended
addressee.  It is subject to copyright, is confidential and may be
the subject of legal or other privilege, none of which is waived or
lost by reason of this transmission.
If the receiver is not the intended addressee, please accept our
apologies, notify us by return, delete all copies and perform no
other act on the email.
Unfortunately, we cannot warrant that the email has not been
 altered or corrupted during transmission.

More information about the Linuxppc-embedded mailing list