[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 12:51 PM, Michal Simek <monstr at monstr.eu> wrote:
> Hi,
>
> 2016-02-15 18:53 GMT+01:00 Joe Hershberger <joe.hershberger at gmail.com>:
>>
>> 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.
>
>
> Anyway you are network custodian and I believe you will tell me which way to
> go to implement
> this mac address reading from eeprom. :-)

Unless someone can compel me otherwise, I think the reference that I
sent should be the way for now.