Jon Smirl wrote: > On 11/13/07, Benjamin Herrenschmidt <[EMAIL PROTECTED]> wrote: >>> That's why Dominic wants to get OpenOCD running on the PowerPC. All we >>> need is the programming documentation for controlling the CPU via the >>> debug hardware. >> Note that this is basically different for every CPU around. > > I'd like to get it for the MPC5200 because of the project I am working > on, an open source audio device. It would be nice if there was a cheap > hardware debugger available for hackers to use on it. Maybe one of the > Freescale developers will see this and send me the right docs. > > Is it radically different? Dominic has been able to support every ARM > 7/9 chip he can get his hands on without too much trouble once the > core support was written. I don't think he has ARM 11 working yet. > >>> Obviously this documentation exist, all of the commercial vendors had >>> to have it to develop their debuggers. Maybe it is already out there >>> and we just don't know where to look. >> Ben.
DISCLAIMER: Extrapolating grossly from almost no knowledge! My understanding is that the Freescale PPC debugger interface is based on the JTAG interface using a proprietary command set. Basically, if you do their magic BDM (JTAG extension) command, you get into an internal scan chain that allows you to read/write the processor internals (registers). The problems are many... * The documentation is only available under NDA, a problem for open source debuggers. * The scan chain is different on every processor, and may be different on different revisions of the same processor. * If you mess up with JTAG, you will probably burn up the CPU. Very literally. I've seen it done. Twice. (Thankfully not my screwup, and it wasn't a PPC so it deserved to die. ;-) The internal scan chain is probably safer, but YMMV. gvb _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
