[U-Boot] imx: Vybrid VF610 mac address issue

[Wang Huan-B18965]

Hi, Benoit,

> -----Original Message-----
> From: Benoît Thébaudeau [mailto:benoit.thebaudeau at advansee.com]
> Sent: Thursday, June 06, 2013 5:46 AM
> To: Fabio Estevam
> Cc: Andy Voltz; u-boot at lists.denx.de; Stefano Babic; Wang Huan-B18965
> Subject: Re: [U-Boot] imx: Vybrid VF610 mac address issue
> 
> On Wednesday, June 5, 2013 11:16:17 PM, Benoît Thébaudeau wrote:
> > Hi Andy, Fabio,
> >
> > On Wednesday, June 5, 2013 11:13:52 PM, Fabio Estevam wrote:
> > > Hi Andy,
> > >
> > > On Wed, Jun 5, 2013 at 5:54 PM, Andy Voltz <andy.voltz at timesys.com>
> wrote:
> > > > I recently tried booting the VF610 support on the Tower board,
> but
> > > > the mac address is reversed in Linux userspace. DHCP/BOOTP seems
> > > > to work properly in u-boot.
> > > >
> > > > I'm booting this kernel:
> > > > https://github.com/Timesys/linux-timesys/
> > > > ref: 2c4ead2dd6da019f5052a69b12c8f5b6b71f8dca
> > > >
> > > > I haven't yet seen how the address is passed to the kernel, but
> > > > our previous u-boot support does not have this issue with the
> same
> > > > kernel. That u-boot branch is also on our github.
> > >
> > > The MAC address is read in the imx_get_mac_from_fuse() function in
> > > arch/arm/cpu/armv7/vf610/generic.c
> > >
> > > Try printing all the elements of mac[] array in this function and
> > > check if the logic is correct there.
> >
> > You probably had programmed the fuses with a MAC address on your
> > board, and then replaced the existing U-Boot with the mainline
> > version. These 2 U-Boot-s may interpret the MAC fuses in a different
> > way. Especially, note that VF610 interprets the MAC fuses with
> > reversed endianness compared to i.MX6 in mainline U-Boot. This is
> > documented in doc/README.<SoC>. There may be the same difference
> > between VF610 in mainline U-Boot and the other version of U-Boot that
> > you used first.
> 
> But if there is such a difference between U-Boot editions, it might be
> worth considering to make mainline U-Boot more consistent with
> Freescale's or others'
> before it is too much widespread. It is especially important if people
> change the U-Boot edition on their board.
> 
> Stefano, Alison, what do you think?
> 
> Alison, have you checked if your implementation in mainline is
> consistent with Freescale's? There may be a difference both for which
> fuse word is used for high/low parts of the MAC address (i.e. word-
> level endianness that I was talking about above), and for the byte-
> level endianness inside each fuse word.
[Alison Wang] Thanks for your comments. In Vybrid's RM, there is no specific descriptions about
how to program the mac address in the OTP Bank4 Word2(OCOTP_MAC0) and OTP Bank4 Word3(OCOTP_MAC1).
So I think it is not formulary which fuse word is used for high/low parts of the MAC address
(i.e. word-level endianness), and for the byte-level endianness inside each fuse word.
Through reading the doc/README.vf610, I think the user could program the fuses correctly.


Best Regards,
Alison Wang