[U-Boot] [PATCH 1/6] net: gem: Add support for reading MAC from I2C EEPROM

[Joe Hershberger]

Hi Michal,

On Mon, Feb 15, 2016 at 11:41 AM, Michal Simek <monstr at monstr.eu> wrote:
> Hi Joe,
>
> 2016-02-15 17:01 GMT+01:00 Joe Hershberger <joe.hershberger at gmail.com>:
>>
>> Hi Bin,
>>
>> On Sun, Feb 14, 2016 at 6:00 AM, Bin Meng <bmeng.cn at gmail.com> wrote:
>> > Hi Michal,
>> >
>> > On Sun, Feb 14, 2016 at 6:03 PM, Michal Simek <monstr at monstr.eu> wrote:
>> >> Hi Bin,
>> >>
>> >> 2016-02-14 3:25 GMT+01:00 Bin Meng <bmeng.cn at gmail.com>:
>> >>>
>> >>> Hi Michal,
>> >>>
>> >>> On Sat, Feb 13, 2016 at 6:39 PM, Michal Simek <monstr at monstr.eu>
>> >>> wrote:
>> >>> > Add support for reading MAC address from I2C EEPROM.
>> >>> >
>> >>>
>> >>> Is this a feature provided by the GEM MAC IP?
>> >>>
>> >>> > Signed-off-by: Michal Simek <monstr at monstr.eu>
>> >>> > ---
>> >>> >
>> >>> >  drivers/net/zynq_gem.c | 16 ++++++++++++++++
>> >>> >  1 file changed, 16 insertions(+)
>> >>> >
>> >>> > diff --git a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c
>> >>> > index b3821c31a91d..ace60c901cb5 100644
>> >>> > --- a/drivers/net/zynq_gem.c
>> >>> > +++ b/drivers/net/zynq_gem.c
>> >>> > @@ -627,6 +627,21 @@ static int zynq_gem_remove(struct udevice *dev)
>> >>> >         return 0;
>> >>> >  }
>> >>> >
>> >>> > +static int zynq_gem_read_rom_hwaddr(struct udevice *dev)
>> >>> > +{
>> >>> > +#if defined(CONFIG_ZYNQ_GEM_EEPROM_ADDR) && \
>> >>> > +    defined(CONFIG_ZYNQ_GEM_I2C_MAC_OFFSET)
>> >>> > +       struct eth_pdata *pdata = dev_get_platdata(dev);
>> >>> > +
>> >>> > +       if (eeprom_read(CONFIG_ZYNQ_GEM_EEPROM_ADDR,
>> >>> > +                       CONFIG_ZYNQ_GEM_I2C_MAC_OFFSET,
>> >>> > +                       pdata->enetaddr,
>> >>> > ARRAY_SIZE(pdata->enetaddr)))
>> >>>
>> >>> This call to eeprom_read() looks to me a board-specific feature, that
>> >>> an on-board eeprom is used to store the MAC address for the GEM?
>> >>>
>> >>
>> >> Right. it is board specific feature I can
>> >> The question is if this should really go to board specific file
>> >> or to be the part of DT binding. I didn't look at the kernel if someone
>> >> has
>> >> some sort of eeprom binding for this case
>> >> but I expect local mac addresses via DT are used. Or passing via
>> >> command
>> >> line does it.
>> >>
>> >> Anyway there is mac_read_from_eeprom() but it is ancient one.
>> >> Do you any preference for the name of function?
>> >
>> > I think the intention of the read_rom_hwaddr op is to read the MAC
>> > address via the ethernet controller defined mechanism (eg: e1000 can
>> > read its MAC address from either an EEPROM or an SPI flash), or via
>> > SoC defined mechanism (eg: the ethernet IP is only seen on a specific
>> > SoC, and reading the MAC address only makes sense on that specific
>> > SoC). If this is a board-specific mechanism, I don't think we should
>> > put the codes into driver's read_rom_hwaddr(). Again, if it is
>> > board-specific, we may not come up with a standard DT binding for such
>> > stuff, unless we can enumerate all possible ways for storing MAC
>> > address on a board (EEPROM, SPI flash, eMMC, SD)?
>>
>> Did you see this: https://patchwork.ozlabs.org/patch/573373/
>>
>> This is the concept I had in mind for handling this sort of thing.
>
>
> This also works for me. I have no problem with both ways. It means this one
> or setting
> up variable in board init file.
> Also is there any hook that mac address will be updated in DTS file
> (local-mac-address)
> to be the same in u-boot and in Linux.

I'm not aware of a common way.

-Joe