[U-Boot-Users] New x86 board booted...now the hard part

Daniel Engström daniel at omicron.se
Mon May 26 08:35:20 CEST 2003

On 2003.05.23 21:00 Marc Singer wrote:
> Yipee!  It boots.
Very good, now there are three of us.

>   1) Daniel, do you think that the 'fs' overrides in mem_init are
>      necessary when ds == fs?
No, that's a left-over from AMDs 16bit code kit which need to use segment 

>   2) How would you expect to override mem_init on another x86 board?
Conditional compilation of sc520_asm.S it is, after all, sc520-specific.
The defines in sc520_asm.S and sc520.c are not there yet, but they should
look like most othe U-boot code:

#ifdef CONFIG_SC520



I think it is cleaner to do this kind of things in the makefile, but it is 
how the U-boot amkefiles are done.

>      It seems to me that we'd be better off with a BSP entry point for
>      RAM initialization that calls the appropriate library
>      function(s).

mem_init is the BSP entry point for RAM initialization. Calling library 
before mem_init is done is not advisabe.

>   3) We ought to be able to share serial driver code between x86 and
>      the risc processors as long as we abstract port accesses the
>      way that the Linux kernel does.  Has this been discussed?

Sure, we should be able to share. No, I have not investigated how that 
would be done.
When I started the 386-port, I looked in a few directories under cpu/* for 
cpu/i386 should contain. All CPU-subdirs I checked contined a serial 
driver, so I
borrowed a 16550 version (from the 405GP i think) and included it slightly 
in cpu/i386.

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