[U-Boot-Users] AT91 Kernel oops when loading kernel from dataflash.

[Ulf Samuelsson]

Raúl Sánchez Siles wrote:
>   Hello all:
>
>   This is the first time I write to the list, and I appreciate the
> big help it gives us users.
>
>   We're using an AT91RM9200 based board called Portux920T. We have
> now a quite stable kernel and u-boot configuration which I attach. We
> manage to include a dataflash inside the portux board and get it to
> work. At least almost, please read on.
>
>   When doing big transfers in memory (10M), we have some kernel
> oopses(see panic.log.zip attached). The oops comes up in the function
> __wake_up_common in the file kernel/sched.c
>
>   The steps to reproduce this are the following:
>
>   1- Start the first bootloader (used the binary provided by atmel).
>   2- Make the first bootloader start u-boot(1.1.6).
>   3- U-boot downloads kernel(2.6.18) from _dataflash_ into RAM.
>   4- Rest of booting till shell prompt.
>   5- Execute for example: dd if=/dev/zero of=/root/borrar bs=1k
>   count=10k 6- Oops!

You do not say that you are loading a ramdisk.
Do you have the file system in dataflash?
If not, I do not see how this can be influenced by the dd command...
If it is, then the 4 MB flash seems small for a 10 MB copy!

I can see two scenarios where the dataflash can cause problems.

1) The dataflash blocksize is not 1024 bytes, it is 1056 bytes
2) You are running the dataflash > 5 Mbps
    The PDC of the SPI must not be starved of bus cycles,
    or you are in trouble unless the H/W manages chipselect through GP I/O.

I would try

$ dd if=/dev/zero of=/root/borrar bs=1056 count=10k

to start with, abnd if this works, start digging.


>
>   If we substitute step 3 for U-boot downloads kernel from _parallel
> flash_ into RAM, the Oops won't happen.
>
>   The kernel has been patched with the latest maxim(2.6.18) patchset
> for the AT91RM9200 microcontroller. The u-boot configuration is also
> attached (portux920T.h).
>
>   We have also tried using different first stage bootloaders we could
> find. Even we compile it ourselves using the RAM initialisation code
> taken from the u-boot. We also have tested several toolchains, from
> emdebian to the one provided by portux.
>
>   We have 64MB Ram and we have tried using 64MB 32bit wide and 32MB
> 16bit wide. Flash and Dataflash are both 4MB.
>   We will much appreciated whatever info or test that could take out
> from this works but... situation. Thank you very much.
>
>   Regards,
>
>
>
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Best Regards,
Ulf Samuelsson
ulf at atmel.com
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