[U-Boot-Users] lastest 1.1.3 CONFIG_SKIP problems with arm920t on rm9200 : pending in queue patch leads to unacceptable slowdown

[Mathieu Deschamps <mathieu.deschamps@com2gether.net>]

Hello,

I'd like to bring your attention on the patch submitted by Anders which is 
pending in the commit queue. On my config it leads to huge slowdown (x10 
slower)  when executing standalone codes in Uboot, whereas its ok under
Linux environnement. 

The problem is set when overriding lowlevel_init function in defining a new 
void one in $(UB-1.1.3)/board/at91rm9200zeph/at91rm9200zeph.c. Indeed, this 
was fine and prevented linker error (undef symb) but it also prevent the I/D 
cache flush and the MMU disabling from happening. 

Is this slowndown happens because of the MMU being activated or because of the 
cache being not flush ? I just can't tell. But in the opposite of Ander's 
reply, calling cpu_init_crit (without calling lowlevel_init of course) has to 
happen even when defining true CONFIG_SKIP_LOWLEVEL_INIT setup. 

Doing so, and testing it for a while it breaks nothing for me.  

In the end, my patch submission on the 20th is valid and workeable 
whether you start standalone application or not (if Linux has started ).



Mathieu Deschamps



On Tuesday 20 September 2005 11:36, you wrote:
> Mathieu Deschamps <mathieu.deschamps@com2gether.net> schreibt:
> >===========
> >--- cpu/arm920t/start.S.orig        2005-09-19 16:35:45.000000000 +0200
> >+++ cpu/arm920t/start.S     2005-09-20 09:09:33.000000000 +0200
> >@@ -156,9 +156,7 @@
> >         * we do sys-critical inits only at reboot,
> >         * not when booting from ram!
> >         */
> >-#ifndef CONFIG_SKIP_LOWLEVEL_INIT
> >        bl      cpu_init_crit
> >-#endif
>
> Calling cpu_init_crit when CONFIG_SKIP_LOWLEVEL_INIT is defined
> doesn't look right and is sure to break e.g. the at91rm9200dk.
>
> >@@ -262,9 +260,11 @@
> >         * find a lowlevel_init.S in your board directory.
> >         */
> >        mov     ip, lr
> >+
> >+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
> >        bl      lowlevel_init
> >+#endif
>
> A slightly different version (making lowlevel_init do noting
> when CONFIG_SKIP_LOWLEVEL_INIT is defined) is included in my
> "[PATCH 1/5] CSB637 - add KB920x support" submitted on the
> 2005-08-25 (pending in Wolfgang's queue).
>
> Cheers
>  Anders