[U-Boot-Users] [PATCH] ppc: Add CONFIG_TOP_HIDE option to hide memory area that doesn't get "touched"

[Stefan Roese]

Hi Matthias,

On Saturday 22 March 2008, Matthias Fuchs wrote:
> I followed this discussion. The DU440 board will also need this fix.
> On the PMC440 board we reserved the top memory region for
> some PCI accessable shared memory. I will check how we can
> handle skipping the top 256 bytes and provide a patch for both of our
> 440EPx boards soon.

Good.

> I did not get into much depth with this issue, but your fix will make the
> logbuffer ram and pram unaligned to a page boundary. I am not sure if this
> is a good idea. Let's say you want to ioremap the pram under Linux you
> cannot let the mapped region end at log bufferbuffer start address because
> it just lost its alignment on a 4k page boundary.

Good point. If nobody objects I'll change the size of CFG_MEM_TOP_HIDE from 
256 to 4k in the next patch version.

Thanks.

Best regards,
Stefan

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