Re: MMU failure, Virtex4-FX60

["Grant Likely" <grant.likely@secretlab.ca>]

On 1/7/08, Robert Woodworth <rwoodworth@securics.com> wrote:
> Hello!
>
> I'm building a new Virtex4-FX60 device.  I have built it with the new
> MPMC3 and a 256MB SO-DIMM.  It works successfully with a "mem-test" type
> embedded program.
>
> I cannot get it to boot a Linux kernel.  I have traced it down to the
> MMU not getting mapped correctly.
>
> I can load the kernel via jtag, get the pre-boot messages on the serial
> but then when it tries to jump to 0xc0002218 (start_here: head_4xxx.S)
> it fails with a "Machine check exception; invalid instruction address".
>
> Using the debugger and examining the memory once the mmu is suppose to
> be configured, I see that it is not mapping 0xc0000000  to the proper
> location.  I'm sure I've set something up wrong in my FPGA and I need to
> re-synthesize.  But what?

Hmmm, I haven't seen that failure mode before.  MMU handling on an of
my virtex platforms has never been a problem.  Take a look at the TLB
registers to see how they are configured to see if the mappings are
really getting written.

What kernel version are you using?

Cheers,
g.

-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
grant.likely@secretlab.ca
(403) 399-0195