Actually I solved this problem by disabling the MMU, but I'd like to fix that and understand why it doesn't work when MMU is turned on.
MMU's initialization code looks like that (for the 0x30000000 address): X_ARM_MMU_SECTION(0x300, 0x300, 256, ARM_UNCACHEABLE, ARM_UNBUFFERABLE, ARM_ACCESS_PERM_RW_RW); /* External CS2 * So it's look like a direct mapping is used. That's why I don't understand why that does not work... Regards, Jeremy -----Message d'origine----- De : [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] De la part de Andrew Lunn Envoyé : vendredi 7 mars 2008 11:14 À : J?r?my Alles Cc : 'eCos Discussion' Objet : Re: [ECOS] MMU, chip select on AT91 On Fri, Mar 07, 2008 at 11:03:31AM +0100, J?r?my Alles wrote: > Hi, > > I?m using a AT91 processor on a AT91RM9200DK board. I?m using a port that > someone in my company did some years ago. Here is my problem: I would like > to use the graphic possibilities of the board. In the development kit, I > have an example driver (source code and bin file). > > If I run the bin file from Zooboot it works fine. > If I build the driver (using arm-elf-gcc) and launch it from Redboot (using > eCos environment) it doesn?t work anymore. > > I?ve traced down the problem to the chip select line 2 (NCS2). This chip > select should be enable when I access data at 0x30000000 but it?s not. I was > thinking that it might be a problem with the MMU initialization that is done > in eCos in AT91 common code. There is no port for the AT91RM9200DK in anonymous CVS. Without the code i cannot say what the MMU is doing. However it does sound like an MMU problem. Andrew -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
