Porting to a new board

[Allen Kennedy Jr.]

Thanks for the great idea to start with a loaded image in ram.

I was able to get it to run, but I can't get the Ethernet to work.
I'm not entirely sure where to begin looking.

I hit devinfo and get:
<snip>
     `---- imx27-fec
          `---- miibus0
          `---- eth0
<...>
drivers:
<...>
SMSC LAN83C185
SMSC LAN8187
SMSC LAN8700
SMSC LAN911x Internal PHY
SMSC LAN8710/LAN8720
fec_imx
Generic PHY
</snip>

This would seem to indicate to me that the drivers are loading. And
that the register happened.
But I'm not sure where to go from here.

In another thread... the advice was given to check the MII address,
although I'm not sure how to interpret the data sheet.
It looks as though the address is 31.  But I could be wrong.  When I
try 31, and do a DHCP the processor hangs.
So I tried 0, and the processor hangs.

Is there a "scan the bus mode" I can use in the fec driver?  I don't
see one, but I may be looking in the wrong spot.

What else can I check?

thanks


On Thu, Sep 19, 2013 at 2:35 AM, Sascha Hauer <s.hauer at pengutronix.de> wrote:
> On Wed, Sep 18, 2013 at 04:44:29PM -0500, Allen Kennedy Jr. wrote:
>> Hello,
>>   I have read the documentation but I believe it to be out of date, as it
>> does not match up with the source from the git tree.
>
> Yes, you're most probably right :(
>
>>
>>   To that end, I am trying to add a new board, and I can not figure out how
>> to do so.  My board uses the mx27 processor, and so I am attempting to
>> closely mimic one of the other mx27 boards, when following the steps here:
>> http://barebox.org/documentation/barebox-2011.05.0/dev_board.html
>>
>> I find the following inconsistencies:
>> 1. include/configs/<boardname>.h  -
>> the configs directory does not exist.
>> 2. modify arch/<architecture>/Kconfig
>>
>>    - add your board (MACH_*) to the list
>>    - add your default text base address for this architecture
>>    (ARCH_TEXT_BASE)
>>    - add BOARDINFO with valueable info for your board
>>
>> None of this exists.
>>
>> 3. modify arch/<architecture>/Makefile:
>>
>>    - add board-$(MACH_*) = <your board_dir>
>>
>>
>> This does not exist
>>
>> And my board will not show up in the menu config.
>>
>> Also I am finding it difficult to locate where I set things like flash
>> size, ram size, etc...  u-boot has a much simpler (if not less documented)
>> layout when it came to boards.  Alas I can not use u-boot, because of the
>> nand flash limitations, and thus why I am attempting to use barebox.
>
> Look at arch/arm/boards/pcm038/. It should contain enough information to
> get you started. To hooking your board up to the build system look at
> arch/arm/boards/Makefile and arch/arm/mach-imx/Kconfig.
>
>>
>> And finally there seems to be some confusiton both in the code and the
>> documentation about the difference between a board and a machine.  What is
>> the difference?
>
> What we have is:
>
> - board: The PCB in front of you
> - SoC: The System on Chip from vendors like Freescale, Marvell,...
> - Architecture: Arm, PowerPC, Mips
> - subarchitecture: i.MX, PXA, usually a subarchitecture is one of
>   arch/*/mach-*
>
> 'machine' is sometimes used for 'SoC', sometimes for 'board' and
> sometimes for 'subarchitecture'. The term shouldn't be used.
>
>>
>> I'm sorry that there is a lot here, but I can not find the proper
>> documentation to answer these questions.
>>
>>
>> Also, for those that are curious, or can help me get around this issue.  I
>> attempting to get this going on a board with an mx27 booted from NAND
>> flash, so I believe I have to use the PBL option to setup and copy out of
>> nand to do the real booting.  If there is any advice on this, I would
>> appreciate it.  I have no other bootloader, only bare metal and a JTAG
>> device.
>
> You don't need the PBL option (you can use it if you want to, it will
> make your binary smaller).
>
> Basically what I would do is:
>
> - Start with a nearly empty lowlevel.c (copy from
>   arch/arm/boards/pcm038/lowlevel.c, remove SDRAM setup
> - Setup the SDRAM via JTAG, make sure it works
> - Figure out a way to send signs of life from your board (setup early
>   UART, flash a LED), add this to early code
> - upload the binary via JTAG to the already configured SDRAM, make it
>   work.
>
> This way you can get a working binary without having the complex process
> of loading from NAND flash before seeing anything. Also with the working
> binary you can use barebox to flash itself to NAND.
>
> Hope that helps.
>
> Sascha
>
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