[U-Boot] [PATCH V2 4/5] net: fec: sharing MDIO for two enet controllers

[Jagan Teki]

On Thu, Mar 22, 2018 at 12:09 AM, Joe Hershberger
<joe.hershberger at ni.com> wrote:
> On Wed, Mar 21, 2018 at 1:29 PM, Jagan Teki <jagannadh.teki at gmail.com> wrote:
>> On Wed, Mar 21, 2018 at 6:54 PM, Peng Fan <peng.fan at nxp.com> wrote:
>>>> >> >
>>>> >> >
>>>> >> >> -----Original Message-----
>>>> >> >> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
>>>> >> >> Sent: 2018年3月21日 17:19
>>>> >> >> To: Peng Fan <peng.fan at nxp.com>
>>>> >> >> Cc: Joe Hershberger <joe.hershberger at ni.com>; Fabio Estevam
>>>> >> >> <fabio.estevam at nxp.com>; U-Boot Mailing List
>>>> >> >> <u-boot at lists.denx.de>
>>>> >> >> Subject: Re: [U-Boot] [PATCH V2 4/5] net: fec: sharing MDIO for
>>>> >> >> two enet controllers
>>>> >> >>
>>>> >> >> On Wed, Mar 21, 2018 at 2:31 PM, Peng Fan <peng.fan at nxp.com>
>>>> wrote:
>>>> >> >> > On i.MX6SX, 6UL and 7D, there are two enet controllers each has
>>>> >> >> > a MDIO port. But Some boards share one MDIO port for the two enets.
>>>> >> >> > So introduce a configuration CONFIG_FEC_MXC_MDIO_BASE to
>>>> >> >> > indicate the MDIO port for sharing.
>>>> >> >> >
>>>> >> >> > To i.MX28, adapt to use the new config
>>>> >> >> >
>>>> >> >> > Signed-off-by: Peng Fan <peng.fan at nxp.com>
>>>> >> >> > Acked-by: Joe Hershberger <joe.hershberger at ni.com>
>>>> >> >> > Cc: Fabio Estevam <fabio.estevam at nxp.com>
>>>> >> >> > ---
>>>> >> >> >
>>>> >> >> > V2:
>>>> >> >> >  adapt mx28 to use FEC_MXC_MDIO_BASE
>>>> >> >> >
>>>> >> >> >  drivers/net/Kconfig       | 9 ++++++++-
>>>> >> >> >  drivers/net/fec_mxc.c     | 8 ++++++--
>>>> >> >> >  include/configs/mx28evk.h | 1 +
>>>> >> >> >  3 files changed, 15 insertions(+), 3 deletions(-)
>>>> >> >> >
>>>> >> >> > diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index
>>>> >> >> > de1947ccc1..c5fd6f648a 100644
>>>> >> >> > --- a/drivers/net/Kconfig
>>>> >> >> > +++ b/drivers/net/Kconfig
>>>> >> >> > @@ -147,9 +147,16 @@ config ETHOC
>>>> >> >> >         help
>>>> >> >> >           This MAC is present in OpenRISC and Xtensa XTFPGA
>>>> boards.
>>>> >> >> >
>>>> >> >> > +config FEC_MXC_MDIO_BASE
>>>> >> >> > +       hex "MDIO base address for the FEC controller"
>>>> >> >> > +       depends on FEC_MXC
>>>> >> >> > +       help
>>>> >> >> > +         This specifies the MDIO registers base address. It is used
>>>> when
>>>> >> >> > +         two FEC controllers share MDIO bus.
>>>> >> >>
>>>> >> >> How about retrieving this from dt? we have board that support dt
>>>> >> >> along with dm supporting.
>>>> >> >
>>>> >> > It's ok to retrieve the info from dt, but we are not only support
>>>> >> > dt, we also need to support non-dt case. Define FEC_MXC_MDIO_BASE
>>>> >> > is the simplest method to achieve that I think.
>>>> >>
>>>> >> But patch adds the same for DM case which usually retrieve the info
>>>> >> from dt, point here is to get rid of ifdef and new CONFIG_ ie where
>>>> >> DM and dts play smart atleast.
>>>> >
>>>> > The uboot fec_mxc driver or net driver is not that sync with linux
>>>> > code, Using dt here, need to parse phy-handle = <&ethphy0>;, then
>>>> > parse ethphy0 parent to get reg, I just think this like hack.
>>>>
>>>> No, I think we can do this with adding new DM MDIO similar to DM PHY which
>>>> recently done. May be some sort of efforts but it is permanent.
>>> We do not have that driver now, so could we first have this patch? When
>>> DM MDIO ready, this piece code could be removed then?
>>
>> ie. up to Joe. Honestly this macro become removed in future, my point
>> here is why we need to maintain dead macro instead of adding proper
>> maintainable stuff. I'm pretty sure adding DM_MDIO is straight forward
>> and as of now just add what we need and rest will implement future.
>> You may become victim to others to move DM_ETH as soon as possible :)
>
> It would be ideal if you wanted to implement DM MDIO, but I can also
> appreciate that this is not already there for you to use. As I
> commented when I acked this, the I'm OK with this approach at this
> time due to the state of the DM support in eth.

As I said before, its your decision.

>
> As a side note, maybe moving other boards that use this NIC to DM_ETH
> and removing non-DM support would be a better cleanup to start with.

To be honest this can't be predictable (until you make a note on
MIGRATION deadline), I still see new boards from i.MX still can't use
dt.