Thanks; that was instructive. I hadn't read up on the 85xx debug exceptions yet.
For posterity, my issue was that even though the code is running out of ddr at this stage, u-boot has left the IVPR pointed at flash. So once head_e500.S invalidated the tlb entry for the flash region, the debug exception vector was inaccessible and a breakpoint sent the processor off the road. As a workaround, I modified u-boot to re-point IVPR when it relocates itself into ddr. Cheers, Kylo Fahd Abidi wrote: >Try the suggestions pointed out in here: > >http://www.ultsol.com/faq-P308.htm > >This is based off suggestions from another customer. Let me know if this >works for you or not. > >Fahd > >-----Original Message----- >From: Kylo Ginsberg [mailto:kylo at veriwave.com] >Sent: Tuesday, April 12, 2005 3:21 PM >To: linuxppc-embedded at ozlabs.org >Subject: bdi2000 + mpc8560ads, very early breakpoints > >I'm running a bdi2000 (with mpc85xx-gdb f/w 1.03) with a mpc8560ads >target, and I'm trying to set breakpoints early on in linux startup (in >the head_e500.S code that sets up tlb's). I'm setting the breakpoints >from within the bdi telnet interface. > >I can: >--succesfully hit a breakpoint set up to any instruction <= the address >of the first 'tlbwe'. >--single step (with the bdi "TI" command) past that 'tlbwe' as far as >I've cared to try > >I cannot: >--hit a breakpoint once the first 'tlbwe' has executed. If I attempt to > >do so, linux startup doesn't proceed, I lose further communication with >the target and the BDI claims "COP Freeze" and I have to reset the >target. > >Btw, the 'tlbwe' in question marks invalid the first tlb1 entry setup by > >u-boot, which pointed at flash address space. Code is running out of >ram at this point. > >I'm probably missing something very basic here. Any ideas? > >Thanks, >Kylo > >_______________________________________________ >Linuxppc-embedded mailing list >Linuxppc-embedded at ozlabs.org >https://ozlabs.org/mailman/listinfo/linuxppc-embedded > >_______________________________________________ >Linuxppc-embedded mailing list >Linuxppc-embedded at ozlabs.org >https://ozlabs.org/mailman/listinfo/linuxppc-embedded > > >
