[U-Boot] [PATCH] net/phy: Fix phy_connect() for phy addr 0

[Joe Hershberger]

Hi Marek,

On Tue, Dec 17, 2019 at 1:39 AM Marek Vasut <marex at denx.de> wrote:
>
> On 11/7/19 9:04 PM, Joe Hershberger wrote:
> > On Thu, Nov 7, 2019 at 1:16 PM Tom Rini <trini at konsulko.com> wrote:
> >>
> >> On Tue, Nov 05, 2019 at 04:05:11AM +0000, Priyanka Jain wrote:
> >>
> >>> Fix 'mask' calculation in phy_connect() for phy addr '0'.
> >>> 'mask' is getting set to '0xffffffff' for phy addr '0'
> >>> in phy_connect() whereas expected value is '0'.
> >>>
> >>>
> >>> Signed-off-by: Priyanka Jain <priyanka.jain at nxp.com>
> >>
> >> Reported-by: tetsu-aoki via github
> >
> > Acked-by: Joe Hershberger <joe.hershberger at ni.com>
>
> Sadly, this breaks systems where a PHY is at address 0.
> I have such an STM32MP1 system with LAN8720 PHY and since this patch, I
> cannot use ethernet. Please revert.

It seems like a case that shouldn't have worked before. What about
this board requires the mask to be all 'f's, other than specifying the
wrong phy address? It seems that in your case the phy address is not
actually 0 (or the computed mask would find it), but your board dts
may be setting it to 0 as an "unknown" value, but the correct unknown
value should be "-1". It seems the issue is with these boards.

Cheers,
-Joe