[U-Boot] Query on MAC address for OMAP3 boards

[Wolfgang Denk]

Dear Mani,

In message <19F8576C6E063C45BE387C64729E739404327A0A22 at dbde02.ent.ti.com> you wrote:
> 
> I am seeing an issue with the OMAP3 EVM boards.
> 
> The MAC address for the SMC911x Ethernet chip is passed from u-boot to the =
> kernel using the
> SMC911x chip memory - "addrh" and "addrl" registers on the SMC chip.

If that is really the case, then I would not rely on this feature, as
it is a  violation  of  U-Boot  design  philosophy  which  says  that
hardware  (including  MAC address registers) must only be initialized
if actually used by U-Boot commands itself. On a  system  which  does
not  performa  nay  network  related  functions  in  U-Boot,  such an
initialization should not happen.

> Scenario 2:
> The ipaddr, serverip and ethaddr environment variables are correct.
> The linux image(uImage) and the ramdisk are both stored on the nand flash. After powering on the
> board, if the uImage and ramdisk is copied from the nand( no network commands are issued).
>
> Linux boots up but the MAC address when linux boots up, the MAC address seen on the linux
> prompt is different.

This is a well-known problem of the Linux Ethernet driver.

And this has been discussed here many, many times before. Please
search the mailing list archives for details.

> The reason seems to be that the MAC address is not initialized in the SMC911x chipset if no
> network commands are issued. I tested it by issuing a 'dchp' commands in scenario 2 and it works
> fine.
>
> Please suggest how to fix this issue.

Define a method for U-Boot to pass the MAC address to Linux, and fix
the Linux driver.

If you are interested in a seminal solution you  might  want  combine
your  efforts  with Grant Likely's recent efforts to introduce device
tree support for ARM Linux. If we had this, the simple solution would
be that U-Boot fills in the correct MAC address in  the  device  tree
passed to Linux.

Best regards,

Wolfgang Denk

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