[U-Boot-Users] The problem on porting to similar FADS860 board

Wolfgang Denk wd at denx.de
Tue May 13 10:15:38 CEST 2003

Dear John,

in message <001d01c31902$4c141780$844da93d at john> you wrote:
> I've checked the archives, but have not found anyone using the 860 with my
> problem.
> I have a MPC860 board ported from FADS860 board. ( TEXT_BASE is also 0x2800000,
> but IMMR is 0x2200000). I have vxworks run OK on it. But when I am porting

Don;t do thiis. There is good reason NOT to  chose  an  IMMR  address
below 0xF0000000 - at least if you intend to run Linux one day.

> For Example as following:  (ELDK1.0 + U-boot-0.3.0)
> --------------------------------------------------------
> located in /cpu/mpc8xx/start.S
>  .globl _start
>  .extern testLed
> _start:
>  lis r3, 0x220 /* my IMMR addr is 0x2200000 */
>  ori r3, r3, 0x0000
>  mtspr 638, r3  /*IMMR SPR is 638*/
>  bl  testLed  /* this is to light LEDs on board(PA0 - PA3)*/
> ----------------------------------------------------------
> located in /cpu/mpc8xx/cpu_init.c
> void testLed(void)
> {
>  int i,k;
>  for(k=0;k<5;k++)
>  {

This cannot work. You added your code much too early, where no  stack
has been set up yet.

My recommendation is not to change cpu/mpc8xx/start.S  if  you  don't
know EXACTLY what you are doing. If you want to insert your own debug
code written in C, then you cannot do this before the comment reading
"let  the C-code set up the rest" (but then you can alos include your
code in cpu_init_f().

Also, you should get yourself a BDI2000 so you can debug your system.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
There are bugs and then there are bugs.  And then there are bugs.
                                                    - Karl Lehenbauer

More information about the U-Boot mailing list