Early UART setup on 2.6 kernel for mpc85xx

[Scott Wood]

On Mon, Aug 13, 2007 at 07:09:40AM -0400, Morrison, Tom wrote:
> >> In order to debug the kernel 2.6, I want setup serial port with 
> >> UART on mpc85xx as early as possible. I add the register access 
> >> code at the beginning of  platform_init(). For example, I try 
> >> to write THR register(0xe0004500). However the system just 
> >> hanging there with this line.

Make sure there's a mapping in the TLB for that address.

> FWIW, you really can't debug the earliest init code 
> because most of that is in assembly. Get a JTAG emulator
> (BDI or Lauterbach) and start stepping through.

It's quite possible to debug assembly code without JTAG. :-)

-Scott