From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3975C701.FB6B19D9@lucent.com> Date: Wed, 19 Jul 2000 10:19:29 -0500 From: Tom Roberts MIME-Version: 1.0 To: clark@esteem.com, linuxppc-embedded@lists.linuxppc.org Subject: Re: Do I shoot myself in the foot first or HEAD.S? References: <1.5.4.32.20000719011945.006845c0@pop.esteem.com> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: clark@esteem.com wrote: > 3. What do I need to do in the ROM before jumping to HEAD.S other than > programming the ram timmings in the UPM( I assume HEAD.S is where everything > starts )? My startup code at 0xFFF00100 simply loads values into r3-r7 and then jumps to physical address 0 (where vmlinux was loaded). But our hardware is initialized from the host, not the on-board CPUs. > 4. Has any one managed to get an EST VisionICE in circuit emulator to work > with linuxPPc? If so How? Would I be better off using the GNU Debuger? I never figured out how to use any of that stuff. I debugged head.S by using r11 and r12 (otherwise unused) to poke cookies into low memory, and traced through head.S until it took off (:-)). But my architecture may be different from yours -- I have a PPC board which plugs into a host which can read/write the on-board RAM via the PCI bus. So I could always dump memory on the board. I had to develop custom console and network drivers using that PCI memory-to-memory interface. I debugged them using our proprietary OS, so once I threaded through head.S it was a short trip to a bash console prompt. Once you get to start_kernel() I doubt any debugger will be of much use (gdb perhaps, because it understands memory mapping, but the ICE won't). Several people have said "don't change head.S". I found I had to, because my board is not anything like any of the CONFIG choices. I did, at least, move it into my private directory and symlink it back where it belongs; ditto for the half-dozen other files I had to change. Tom Roberts tjroberts@lucent.com ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/