Grant,

I've pulled the latest git and built a mpc5200_simple system with a 
minimal dts.
There's not a single char put on the console ....



Grant Likely schrieb:
> On Sun, Mar 16, 2008 at 1:15 PM, André Schwarz
> <Andre.Schwarz@matrix-vision.de> wrote:
>   
>> All,
>>
>>  I'm quite stuck in getting our MPC5200B based systems work on 2.6.24+
>>  ... maybe someone could give me some hints.
>>  Up to now the systems have been running on 2.6.19 without any problems.
>>
>>  This is what I've done so far :
>>
>>  - get a recent system with 2.6.19 running and keep the toolchain (gcc
>>  4.0) including RFS uImage.
>>  - latest bootloader (u-boot 1.3.2) is running fine with dtb support.
>>  - Kernel and RFS images are available via bootp/tftp
>>  - device tree blob seems ok, i.e. u-boot can display the blob and fill
>>  in all clocks correctly.
>>  - Kernel gets called with Kernel, RFS and dtb on suitable adresses
>>  (0x100000, 0x600000, 0x5F0000).
>>  - nothing more happens. It looks like the console isn't working properly
>>  - maybe worse ...
>>     
>
> Can you either halt the processor or reset the board and access memory
> after this point?  You should see if you can access __log_buf (Look in
> System.map for the address and subtract 0xc0000000 to get the physical
> address).   __log_buf should give you clues about how far booting
> progresses.
>
>   
(c033d4b4 b __log_buf) yields all zeroes - nothing logged at all.

Examining the CPU state with the bdi shows :

    Target CPU        : MPC8280/8220/5200 (Zeppo)
    Target state      : debug mode
    Debug entry cause : COP halt
    Current PC        : 0xc000552c
    Current CR        : 0x48000042
    Current MSR       : 0x00009032
    Current LR        : 0xc00166c0

The program counter shows the adress of "irq_set_virq_count" which has a 
BUG() macro. Looks like this one evaluates to true.

What do you think ?

>>  The kernel has been build using the "MPC5200 simple" setup. I've added
>>  our board identifier "mv,mvbluecougar" to the list of supported boards
>>  in the "mpc52xx_simple.c" file. This identifier is used in the dtb as
>>  well of course. This should be enough along with a valid device tree
>>  blob, isn't it ? Did I miss anything already ?
>>     
>
> Yes, this should be enough (on a side note; it should probably be
> "matrix-vision,bluecougar" unless of''mv' is your company's stock
> ticker symbol).
>
>   
>>  As far as I did understand by reading the docs it should be possible
>>  running a general MPC52xx kernel with a custom dtb ? Is this correct ?
>>     
>
> That is correct.
>
>   
>>  The dts file has already been reduced to a minimum, i.e. only the cpu,
>>  pic, xlb and a few nodes like psc1 and psc2 are present. No bestcomm,
>>  pci, ata or "advanced" features like mtd partitions. All I want to get
>>  working is the serial console on "/dev/ttyPSC0".
>>     
>
> Cheers,
> g.
>
>   

regards,
Andre


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