[U-Boot-Users] PPC: How to access RAM location 0x0 (unmapped) ?

[KokHow Teh]

The reason of the crash was because I put get_ram_size() before the sdram
controller was initialized. I don't know how it works in sbc8240 but this
is what I get in tqm8260:

        /* We must be able to test a location outsize the maximum legal size
         * to find out THAT we are outside; but this address still has to be
         * mapped by the controller. That means, that the initial mapping has
         * to be (at least) twice as large as the maximum expected size.
         */

      Now it works.

Thanks.


Wolfgang Denk <wd at denx.de>@denx.de on 04/28/2005 01:55:16 PM

Sent by:    wd at denx.de


To:    "KokHow Teh" <KokHow.Teh at marconi.com>
cc:    u-boot-users at lists.sourceforge.net

Subject:    Re: [U-Boot-Users] PPC: How to access RAM location 0x0
       (unmapped) ?


In message <OF5DF9F216.6A5D85BA-ON48256FF1.0012D4AD at uk.marconicomms.com>
you wrote:
>
>       board/sbc8240.c initdram() calls get_ram_size() with CFG_SDRAM_BASE
> = 0. Put it into board/mpc8260ads/mpc8260ads.c. and it crashes....

Then either don't do that, or fix it. There are many, many PPC boards
using get_ram_size() with CFG_SDRAM_BASE==0 which just work fine.

There is no reason why this should be any problem.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
That was the thing about deserts. They had their  own  gravity.  They
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