Subject: Moving from 2.4 to 2.6 kernel

From: Chris Dumoulin <[email-masked]>
Date: Thu, 04 May 2006 13:32:33 -0400

I am trying to take a working embedded linux system from kernel 2.4 to 
2.6. The hardware is a custom board using a Virtex II Pro with PPC405 
processor.
The working system uses u-boot 1.1.1 with linux kernel 2.4.18.

I am using the same u-boot and I am trying to port linux kernel 2.6.15 
to our platform. Using the stuff from the working 2.4 kernel port and 
other PPC4xx platforms in the 2.6.15 code as examples, I believe I have 
done everything required to get the kernel booting. However, the kernel 
seems to hang after being uncompressed. Here is what I see after running 
bootm from u-boot:

## Booting image at 00400000 ...
   Image Name:   Linux-2.6.15 ICS
   Image Type:   PowerPC Linux Kernel Image (gzip compressed)
   Data Size:    605592 Bytes = 591.4 kB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK
## Loading RAMDisk Image at 00800000 ...
   Image Name:   SELF CRD
   Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
   Data Size:    1430581 Bytes =  1.4 MB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
   Loading Ramdisk to 03e5c000, end 03fb9435 ... OK

My first thought was that I was simply not setting up the console 
properly, and was not seeing the printk output, but I don't think I'm 
even getting that far. I tried flashing an LED in start_kernel (in the 
file init/main.c) and also in my platform_init function, but I get 
nothing. I think the kernel is hanging somewhere very early on, maybe 
when the MMU is enabled. I tried looking at the log buffer by following 
the steps in section 14.3.3 of the DULG (Linux Post Mortem Analysis), 
but I don't see anything there.

Any ideas would be appreciated.

Regards,
Chris
-- 
*--Christopher Dumoulin--*
Software Team Leader

<http://ics-ltd.com/>
<http://ics-ltd.com/>

Interactive Circuits and Systems Ltd.
5430 Canotek Road
Ottawa, ON
K1J 9G2
(613)749-9241
1-800-267-9794 (USA only)

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