Linux boot fails after MMU (MPC8260)

Linux boot fails after MMU (MPC8260)

[Christian.Peter]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1614 bytes --]

Hi

I try to boot linux 2.4.0test8 on a custom 8260 board. It fails to start the kernel (no output) and
i think it hangs somewhere after the mmu initialization (ppc/kernel/head.S).
My knowledge of the mmu and the 8260 is not very good, therefore i'm not sure!
A prior co-worker (unfortunately not in the company anymore) had successfully started the kernel
on a SBC8260 board with a vxworks bootloader and some patches for the mbxboot.
I have near the same configuration, some difference in the vxworks bootloader (chip-select, IMMR 0x0f00000), but
i set this new in mbxboot/head_8260.S to the following values.

Memory Map
----------
0x00000000     60x SDRAM
0x20000008     some LEDs
0xFE000000     Flash
IMMR           0xF0000000

Currently i'm debugging with 2 LEDs on the board and i can switch the LED's on and off until
the RFI. After RFI the code should jump to start_here, but it never gets there.

  ppc/kernel/head.S

  mfmsr r0
  ori r0,r0,MSR_DR|MSR_IR
  mtspr SRR1,r0
  lis r0,start_here@h
  ori r0,r0,start_here@l
  mtspr SRR0,r0
  SYNC
  RFI                       /* enables MMU */

This is a extract of the terminal output.

  TFTP_CLIENT...
  Starting at 0x400000...

  CPU/CPM/BUS: 165/132/66 Mhz

  Ethernet (in decimal): 0:160:30:1:4:5

  loaded at:     00400000 0040B274
  board data at: 00FFFFC0 00FFFFEC
  relocated to:  00200100 0020012C
  zimage at:     0040B274 0047F33D
  avail ram:     00480000 01000000

  Linux/PPC load:
  Uncompressing Linux...
  done.
  Now booting the kernel

Is this a configuration problem (memory map)? Any ideas or suggestions?

Many thanks in advance.

Chris

Re: Linux boot fails after MMU (MPC8260)

[Dan Malek]

Christian.Peter@ascom.ch wrote:
>
> Hi
>
> I try to boot linux 2.4.0test8 on a custom 8260 board.

Where did you get the sources?  There have been some problems with
the 8260 due to other 60x/7xx generic changes in the sources.

> My knowledge of the mmu and the 8260 is not very good,

Don't worry about it.  There is nothing wrong with the MMU code,
it is elsewhere.  If you are trying to use VisionICE or anything
other than the Abatron BDI2000 for JTAG debugging, they become
useless once the MMU is enabled.  This appears like an MMU bug,
but it is really a debugger bug.

For now, the only working version of Linux on the 8260 is from
the MontaVista web site.  It is a -test2 version.  If you have
access to the FSM Labs BitKeeper sources, I will be updating these
for the 8260 before the end of the week.


	-- Dan

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Linux boot fails after MMU (MPC8260)

[David Schleef]

On Thu, Jan 04, 2001 at 01:24:15PM -0500, Dan Malek wrote:
>
> For now, the only working version of Linux on the 8260 is from
> the MontaVista web site.  It is a -test2 version.

Don't be so pessimistic... =)  I've been running the bitkeeper
kernel on an 8260 for several months now, synchronizing every
few weeks.  Works fine, except for the occasional bug hunt.


> If you have
> access to the FSM Labs BitKeeper sources, I will be updating these
> for the 8260 before the end of the week.

I have an ever-increasing patch that I should probably clean
up and send to you, but I keep putting it off.  Even in its
current hackish form, it should be useful for bug hunting.
Let me know.





dave...


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Linux boot fails after MMU (MPC8260)

[Dan Malek]

David Schleef wrote:

> Don't be so pessimistic... =)  I've been running the bitkeeper
> kernel on an 8260 for several months now, synchronizing every
> few weeks.  Works fine, except for the occasional bug hunt.

I'm still breaking it on a regular basis, so I don't want to
imply it will always work :-).  I try not to check it in that
way, but sometimes I do just so I don't lose anything or get
too far behind.  I'm glad it is working for you.

> I have an ever-increasing patch that I should probably clean
> up and send to you, but I keep putting it off.

Well, it is much nicer to receive small patches that are easy
to incorporate and test.  Please don't wait too long.

Thanks.


	-- Dan

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/