[U-Boot] [PATCH v7 00/15] SiFive FU540 Support

[Bin Meng]

On Tue, Feb 12, 2019 at 5:09 PM Andreas Schwab <schwab at suse.de> wrote:
>
> On Feb 12 2019, Bin Meng <bmeng.cn at gmail.com> wrote:
>
> > On Tue, Feb 12, 2019 at 4:34 PM Andreas Schwab <schwab at suse.de> wrote:
> >>
> >> On Feb 12 2019, Anup Patel <anup at brainfault.org> wrote:
> >>
> >> > This is because we don't have place to put U-Boot environment
> >> > variables as of now on Unleashed board. This will be solved once
> >> > we have SPI driver and SPI_MMC driver for Unleased board.
> >>
> >> Isn't the MAC part of the initial DT?
> >>
> >
> > My understanding is that U-Boot should fixup the DT using the
> > <ethaddr> environment value, before jumping to Linux.
>
> But where does it get the env var from?  Why would it need to modify the
> MAC?
>

The env var is stored in whatever supported media in U-Boot. Not like
PCI NICs which normally have EEPROM to store pre-flashed MAC address
by their vendors, for most embedded network controllers in the SoC,
normally there is no hardware provided mechanism to ensure a unique
MAC address, instead it relies on software to program one to the
hardware before bringing it up. In the U-Boot case, it's the <ethaddr>
env.

Regards,
Bin