Re: [PATCH v3 4/4] arm: kirkwood: Pogoplug-V4 : Add board implementation files

Tony Dinh
2022-01-19T23:24:23Z

fHi Stefan,

On Wed, Jan 19, 2022 at 6:37 AM Stefan Roese <sr@denx.de> wrote:
>
> Hi Tony,
>
> On 1/19/22 02:31, Tony Dinh wrote:
>
> <snip>
>
> >>> +#if defined(CONFIG_RESET_PHY_R)
> >>> +/* Configure and initialize PHY */
> >>> +void reset_phy(void)
> >>> +{
> >>> + u16 reg;
> >>> + int phyaddr;
> >>> + char *name = "ethernet-controller@72000";
> >>> + char *eth0_path = "/ocp@f1000000/ethernet-controller@72000";
> >>> +
> >>> + if (miiphy_set_current_dev(name))
> >>> + return;
> >>> +
> >>> + phyaddr = fdt_get_phy_addr(eth0_path);
> >>> + if (phyaddr < 0)
> >>> + return;
> >>> +
> >>> + /*
> >>> + * Enable RGMII delay on Tx and Rx for CPU port
> >>> + * Ref: sec 4.7.2 of chip datasheet
> >>> + */
> >>> + miiphy_write(name, phyaddr, MV88E1116_PGADR_REG, 2);
> >>> + miiphy_read(name, phyaddr, MV88E1116_MAC_CTRL_REG, &reg);
> >>> + reg |= (MV88E1116_RGMII_RXTM_CTRL | MV88E1116_RGMII_TXTM_CTRL);
> >>> + miiphy_write(name, phyaddr, MV88E1116_MAC_CTRL_REG, reg);
> >>> + miiphy_write(name, phyaddr, MV88E1116_PGADR_REG, 0);
> >>
> >> Please take a look at drivers/net/phy/marvell.c / m88e1310_config().
> >> Here you will find (amongst others):
> >>
> >> /* Set RGMII delay */
> >> phy_write(phydev, MDIO_DEVAD_NONE, MIIM_88E1310_PHY_PAGE, 0x0002);
> >> reg = phy_read(phydev, MDIO_DEVAD_NONE, MIIM_88E1310_PHY_RGMII_CTRL);
> >> reg |= 0x0030;
> >> phy_write(phydev, MDIO_DEVAD_NONE, MIIM_88E1310_PHY_RGMII_CTRL, reg);
> >>
> >> Can't you use the Marvell PHY driver instead of this ad-hoc
> >> implementation? I didn't check the compatibilty of your PHY and this
> >> driver though.
> >
> > Thanks for the advice. Marek had a similar comment regarding this code.
> >
> > https://lists.denx.de/pipermail/u-boot/2021-December/470019.html
> >
> > Marek said,
> > "There the m88e1118_config() method already does one thing of what you
> > are doing here: enabling rgmii delays. It also sets LED config, but
> > does not reset the PHY. You can add call to phy_reset() there..."
> >
> > Currently, all other Kirkwood boards also use this old ad-hoc
> > implementation. And the PHY addr is different in some of these boards.
> > If we add phy_reset() in m88e1118_config(), we would need to make sure
> > all existing boards that use the driver will work... OTOH, perhaps we
> > can keep the phy_reset() call in each Kirkwood board...
>
> I should be checked, if this phy_reset() is really necessary. Perhaps
> by checking in the Linux Kernel code as well and the documentation of
> the PHY.

I believe it is necessary. During testing Kirwood boards with Marvel
Alaska chip, if the PHY reset call is timed out, we don't have a
network. But I will try without phy_reset() using the new driver to
see how it behaves.

> > Sounds like an approach that will potentially touch a common area, so
> > I think it is best that I will do the modernization and more testing
> > in a separate patch series, after we're done with this Pogo V4 board.
> >
> > Does that sound reasonable?
>
> Yes, I'm fine with this approach. Let's handle this in some follow-up
> patches ( from you ;) ).

I will :)

Also, I will resend this series to rearrange the patch order.

Thanks,
Tony

> Thanks,
> Stefan