[ECOS] FW: Problems with virtual vectors

Robert Cragie rcc@jennic.com
Mon Mar 15 09:29:00 GMT 2004


I have solved this problem - it turned out to be a hardware memory mapping
issue not a software issue.

My assumption now is that there are no problems associated with this area.

Robert Cragie, Design Engineer
_______________________________________________________________
Jennic Ltd, Furnival Street, Sheffield, S1 4QT,  UK
http://www.jennic.com  Tel: +44 (0) 114 281 2655
_______________________________________________________________

-----Original Message-----
From: Robert Cragie [mailto:rcc@jennic.com]
Sent: 10 March 2004 19:48
To: ECOS; OpenRISC
Subject: Problems with virtual vectors


I am trying to debug some failing code for eCos on an OpenRISC platform.

Basically, I am using the same configuration as a previous build which
worked fine before with the following differences:

Debug UART is at 0x30000000 instead of 0x90000000
RAM starts at 0xf0000000 instead of 0x00000000
UART interrupt is on interrupt 6 not 2

I have a very simple bootstrapper at 0x100 (where the OpenRISC jumps to on
reset) which set the EPH bit in the SR to relocate the exception vectors to
0xf0000000, then jumps to 0xf0000100. The code is externally loaded in RAM
prior to the bootstrapper running.

What happens is this:

enter:
hal_if_init(), which calls
cyg_hal_plf_comms_init, which calls
set_debug_comm(CYGNUM_HAL_VIRTUAL_VECTOR_DEBUG_CHANNEL).

In this function, it seems to fail to return from a call to
CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_IRQ_DISABLE);

The values I record are:

__chan = 0xf0008828
*__chan = 0xf0008828
(*__chan)[5] = 0x00000000

I am assuming 5 is the index into the table for the control function, but
this seems to be NULL. Or am I barking completely up the wrong tree? I do
find the virtual vector stuff very arcane! I will try and work out what the
working code does tomorrow but any help would be appreciated.

Robert Cragie, Design Engineer
_______________________________________________________________
Jennic Ltd, Furnival Street, Sheffield, S1 4QT,  UK
http://www.jennic.com  Tel: +44 (0) 114 281 2655
_______________________________________________________________


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss



More information about the Ecos-discuss mailing list