bbram access problems

Tobias Otto-Adamczak toa at
Thu Dec 12 09:09:11 EST 2002

Jörn Engel, 2002-12-12, 14:45h:

> > We're trying to use BBRAM on a VersaLogic VSBC-6 m-b.  We use the slram
> > driver and the 2.4.18 kernel.  The problem is that we can't acces the
> > entire memory of the BBRAM, just the first 64k page.
>                                              ^^^
> >
> > Other problem: we added to our lilo.conf:
> >
> > append="slram=BBRAM,0xE0000,+0x10000"
>                               ^^^^^^^^
> If you can read hex, you will notice that you told slram to map 64k.
> Change the append line in your /etc/lilo.conf.

I think its correct because that BBRAM (how much is it, anyway ?) is
mapped page-wise into the physical memory space from 0xE0000 - 0xEFFFF
and you have to select pages if you want to access more than the first

> > append="slram=BBRAM,0xE0000,+0x10000"
>                       ^^^^^^^
> slram took memory from the first Megabyte. Is this correct? Does you
> machine have only 896k of memory plus the bbram? I doubt it. ;-)

According to the manual, that address looks fine. Geoffroy, it also says
"CMOS setup is used to choose between DRAM and PC/104 for three sections
of memory from 0C0000h to 0EFFFFh." (p.52) Did you do the right settings

> Figure out, how much memory you have, how much bbram and where the
> bbram starts in the address range. Then you can come back or - better
> yet - read up what the "slram=" and "mem=" parameters do.
> Understanding the problem beats having it solved by someone else. :-)

Other question: does the slram driver map this area in when it is
already covered by the kernel ?


More information about the linux-mtd mailing list