Re: RAM size configuration in IXP425

[Marc Singer <elf@xxxxxxxxx>]

On Fri, Feb 04, 2005 at 07:51:39AM +0530, Manasvini wrote:
> Hi all,
> I am using an IXP425 based board which is configured with 64 MB RAM.When
> the board is reset and redboot comes up, it shows only 32 MB of RAM.In
> the kernel configuration , in  General Setup->default kernel command
> string : when i set mem=32M@0x00000000 and run all my applications it
> works fine, except that my system requires more system RAM than that.
> 
> when i modify this to mem=64M@0x00000000 the kernel boots up fine and
> some applications ( that together consume less than 32 MB of RAM)run
> ok.even 'top' shows about 62 MB of total memory
> 
> But when I load some other RAM intensive applications I get oops errors,
> or kernel panic (unable to handle paging request at virtual address or
> kernel null pointer dereferencing ).
> 
> Is there some other configuration option that I need to setup for using
> the whole 64 MB or something else that I have missed out?Does whatever
> redboot shows  have anything to do with how much RAM we have access to
> in the system?.
> Thanks in advance,
> Manasvini

I don't know about your specific situation.  I believe that some of
the ixp kernels are completely hardwired.  The command line, for
example, is not passed from the boot loader.  Your hack might be a
good start, but the loader needs to initialize the SDRAM controller
properly.

I've been working on a new boot loader
<http://wiki.buici.com/bin/view/Projects/ApexBootloader> and it now
runs on the ixp42x.  I don't have 64MiB hardware, so I haven't made
that change.  It ought to be a one-liner, though.

APEX uses ATAGS to pass memory information to the kernel.  If your
kernel doesn't read atags, then it isn't that much of a help.


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