hi wolfgang, El Tue, Dec 08, 2009 at 09:33:18PM +0100 Wolfgang Denk ha dit:
> In message <20091208151358.gd31...@darwin> you wrote: > > > > i am starting to look at this issue and it seems i need some more guidance: > > > > before relocating U-Boot to RAM for ARM920T processors a jump to the > > label *lowlevel_init* is performed, where RAM timings are supposed to > > be set up. in the patch i sent these operations are performed in > > assembly and you asked me to rewrite them in C. > > > > i'm relativly new to low-level setup, so i apologize if the following > > question sounds plain stupid to you: is C really available at this > > point? if my interpretation of the code in cpu/arm920t/start.S is > > correct, C code starts at start_armboot, after relocation of > > U-Boot. and after that point i'd think it's to late to change RAM > > timings as U-Boot is running from RAM. > > After relocation we have a full-blown, "normal" C runtime environment. > Before that, you can use C as well, if you mind the restrictions (like > data and bss not being available/writable yet, no real stack, etc.). > > > could you please give some advice to clear my confusion and maybe > > provide a pointer to a board/cpu which handles low-level setup in > > the intended way? > > If you check theinit code in cpu/arm920t/start.S you will notice that > one of the really early things it does is calling coloured_LED_init() > and red_LED_on(). Note that these functions are implemented in C. thanks a lot for your explications and for providing an example best regards -- Matthias Kaehlcke Embedded Linux Developer Barcelona Insanity: doing the same thing over and over again and expecting different results (Albert Einstein) .''`. using free software / Debian GNU/Linux | http://debian.org : :' : `. `'` gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `- _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot