MTD Mapping driver - out of vmalloc space

Chris Elston chris.elston at
Tue Apr 12 20:07:38 EST 2005

> > How about setting PAGE_OFFSET to 0x80000000, that is 2G/2G split?
> > It would make enough virtual address space. I've never tried on PPC,
> > so I don't know the side effect of this. 
> This is the ideal solution.  It works fine with the caveat that
> you have to be very aware of the virtual memory map of your board
> port when doing this.  On ppc32, we have very fine grained options
> for manipulating this and other parameters under Advanced Options.
> If the original poster can provide more details then we can tell
> him the exact settings to use.

Thanks for everyone's input on this, I've moved the kernel virtual
base address to 0xa0000000, and it works fine now.  

I'm still not convinced that this is a future proof solution 
though.  What happens when I get a board with 512MB Flash 1GB SDRAM?
I can push the top of the SDRAM out to the high mem area, but I'll 
have to encroach further into user space to map the Flash.  There's
no good reason that the whole of the Flash need be mapped at the same
time. (Perhaps performance?)



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