From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Debugging kernel on mpc7448 From: Cajus Pollmeier To: Linuxppc-dev@lists.ozlabs.org Content-Type: text/plain; charset="UTF-8" Date: Wed, 03 Nov 2010 16:02:28 +0100 Message-ID: <1288796548.3609.49.camel@frost> Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello there, I'm currently trying to get a kernel upgrade from 2.6.11 to 2.6.31 working with u-boot/cuImage.c2k on a custom marvell discovery 3 board. In the moment, the following steps work: * u-boot (1.1.4, not changeable in the moment) runs from flash and offers a prompt * loading cuImage.c2k * running the code of wrapper.c until calling vmlinux.addr * entering __start in head_32.S and running until early_init gets called The systems then hangs until the watchdog resets the board. In this early stage, I've no output to the serial console - which is the only way to see what's going on there without having a development board with single step capabilities. To track it until early_init, I tried to place a stupid "blr" in head_32.S, in order to get back to wrapper.c - which writes out a message to the serial console in case the kernel "accidently" gets back to it. >>From now on, I'm not sure if early_init is properly called. The blr after the call is either not reached or there's something going on which is beyond my limited knowledge of ppc assembler. Maybe u-boot gets overwritten, but the blr isn't even reached if I change early_init by just returning 0U immediately. Hmm. Any pointers to help debugging would be really appreciated ;-) Cheers, Cajus