[U-Boot-Users] Reset issue on mpc85xx

[U-Boot-Users] Reset issue on mpc85xx

[urwithsughosh at gmail.com]

Hello,
    I am working on a custom board having mpc8560 and mpc8540. On
    porting the v1.3.0-rc1 u-boot, i get a peculiar issue. The board
    does not reset on giving the 'reset' command. This is observed
    only on the release candidate version of u-boot. I've also ported
    the 1.2.0 release and there it works fine.

    I tried debugging the issue by putting some debug statements, in
    the board.c file after the init_sequence, and what i observe is
    that the msr register is getting cleared. But the 1.2.0 version
    shows the correct value, i.e 0x1200 which is programmed in the
    start.S. After setting the MSR[DE] bit in the do_reset function
    along with the DBCR0 register settings, the board resets correctly. 

    Am i missing something. Please throw some light on it.

-- 
sughosh

[U-Boot-Users] Reset issue on mpc85xx

[urwithsughosh at gmail.com]

On Fri Sep 14, 2007 at 02:54:31PM -0400, urwithsughosh at gmail.com wrote:

> I am working on a custom board having mpc8560 and mpc8540. On
> porting the v1.3.0-rc1 u-boot, i get a peculiar issue. The board
> does not reset on giving the 'reset' command. 

  I think the issue lies in the start.S file. The MSR is getting
  cleared before jumping out of the last 4k page to _start_cont, where
  SRR1 (which is 0x0) gets written to the MSR.

  Earlier the initialisation of the MSR was done in _start, which was
  after the jump out of the last 4k page. Now the MSR value gets
  overwritten on jumping out of the last page. 
 
  Is there any specific reason as to why the MSR initialisation is
  moved in the last 4k page.
    
-- 
sughosh