memory dump on mips

[Andi <opencode@gmx.net>]

Hi list,

we are working on an embedded Linux device with a Sigma SMP8634 (MIPS
4KEc 300MHz CPU) mounted on it. Unfortunately we don't have access to
the kernel running on the system.

We figured out, that the bootloader loads the kernel image to 0x90020000
(physical address). So it should be possible to read the image from that
address later on in Linux. We are not sure if our approach does not work
because of the memory protection that the SMP8634 offers, or if we do
something wrong.

This approach for a kernel module works on ARM9 (with MMU):
<code>
memory = ioremap_nocache(0x90020000, 20);
char byte = readb(memory);
</code>

Well, on mips this just throws 0x00.
Is this supposed to work on mips as well? Or do I have to deal with
"remap_pfn_range" or even VMA and "vm_ops->nopage"?


Thank you very much in advance

Regards,

andi