On Sat, Apr 25, 2009 at 03:13, Alessio Sangalli [off-list ref] wrote:

Hi I am working on a framebuffer that uses the system memory.

What I mean here is that I need to pass mem=120M to a system that has
128MB to "reserve" 8MB of memory for the framebuffer; then I program the
hardware to use that region of memory.

The reason I do this is that it seems impossible to kmalloc more that
4MB of contiguos physical memory with the Linux Kernel.

Bottom line, I do not know how to map those 8MB back to userspace. If
userspace opens mmaps /dev/mem and writes to the appropriate location it
can access the fb perfectly.

Any hints? All of this is on ARM9.

Alternatively, you could use__alloc_bootmem() in the early platform
code to reserve
the memory, cfr. arch/powerpc/platforms/ps3/setup.c

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

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