Re: [PATCH v2 1/3] net: eth-uclass: Introduce NET_PREFER_ROM_MAC_ADDR

[Detlev Casanova <detlev.casanova@collabora.com>]

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On Monday, April 22, 2024 3:47:21 P.M. EDT Marek Vasut wrote:
> On 4/22/24 3:56 PM, Detlev Casanova wrote:
> > On some boards, a MAC address is set based on the CPU ID or other
> > information. This is usually done in the misc_init_r() function.
> > 
> > This becomes a problem for net devices that are probed after the call to
> > misc_init_r(), for example, when the ethernet is on a PCI port, which
> > needs to be enumerated.
> > 
> > In this case, misc_init_r() will set the ethaddr variable, then, when
> > the ethernet device is probed, if it has a ROM address, u-boot will warn
> > about a MAC address mismatch and use the misc_init_r() address instead
> > of the one in ROM.
> > 
> > The operating system later will most likely use the ROM MAC address,
> > which can be confusing.
> > 
> > To avoid that, this commit introduces NET_PREFER_ROM_MAC_ADDR that can
> > be set for boards that have such an interface.
> > 
> > Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> 
> Won't the system pick ROM MAC if $ethaddr is not set ?

Yes, and in the case of rockchip, misc_init_r() will set an $ethaddr based on 
the cpuid, which makes the eth driver use that instead of the ROM one.

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