[U-Boot-Users] [PATCH] fixed reset command on mpc8xx

[U-Boot-Users] [PATCH] fixed reset command on mpc8xx

[Andreas Oberritter]

This patch does reset on 8xx like the linux kernel does it. Works
without crashing u-boot unlike the previous version. Tested on mpc823.

Changelog:

Patch by Andreas Oberritter, 19 July 03
 - fixed reset command on mpc8xx
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[U-Boot-Users] [PATCH] fixed reset command on mpc8xx

[Wolfgang Denk]

Dear Andreas,

in message <1058581655.1560.31.camel@localhost> you wrote:
> 
> This patch does reset on 8xx like the linux kernel does it. Works
> without crashing u-boot unlike the previous version. Tested on mpc823.

There is no  problem  with  U-Boots  implementation  of  the  "reset"
command  when  you configure your board correctly. Therefore I see no
need to "fix" anything. I reject this patch.

> +	dummy = immap->im_clkrst.res[0];
> +

I know that the Linux kernel uses this implementation, but it is IMHO
a very bad idea to rely on the behaviour when writing to  a  reserved
area in the dual ported RAM. The next version of 8xx processors might
use this area for something.

If you feel the current implementation needs improvment, please  feel
free to implement what we use for the 8260 in our Linux kernel source
tree:

- Get base address mapped by BR0/OR0
- Enable CheckStop Reset
- Invalidate BR0 mapping
- Set MSR and cause reset by attemting to access the base address
  formerly mapped by BR0/OR0


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
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