Re: Kernel oops when initializing ethernet driver

["Patrick Huesmann" <tricknology@gmx.de>]

> Hi Patrick,
>
> Patrick Huesmann wrote:
> > Hi,
> >
> >
> >>>Interestingly, the kernel only crashes when accessing that one
> >>
> >>particular
> >>
> >>>register (at offset 0x0040). Every other register in that range can be
> >>>written to and read from w/o problems.
> >>
> >>So that sounds like a hardware problem, doesn't it.  This is one of
> those
> >>things where the FPGA has a hard PPC core and a bunch of VHDL
> >>peripherals?
> >
> >
> > Yes, exactly. The peripherals are connected to the PPC core via the OPB
> > (on-chip peripheral bus) and now I must assume that the address decode /
> > "chip" select logic within that OPB is buggy or not configured right.
> >
>
> AFAIK Xilinx recommends to use PLB version of the ethernet controller.
> For performance reasons at least.
>
> >
> >>The good thing there is that the VHDL isn't much harder
> >>to fix than C code.  That would be my wild guess - the VHDL is not
> >>decoding the address correctly.
> >
> >
> > I don't even know if we have the VHDL source - the peripherals are
> > ready-to-go logic units that are just inserted in the FPGA design.
> >
> Do you use EDK to build your design?
> >
> >>However, also check that you are not accidentally writing past 0x0040.
> >>For instance, if 0x0040 is a byte address and you write 16 bits you'll
> >>be writing to 0x0040 and 0x0041.
> >
> >
> > It is a 32-bit access at 0x0040.
> >
> > Thanks,
> > Patrick
> >
>
> In your kernel boot messages do you see a line similar to:
>
> eth0: Xilinx EMAC #0 at 0x60000000 mapped to 0xC9015000, irq=30
>
> Is the physical address in your log the one you expect?
>
>
> Best regards,
> Andrei
>


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