Re: v2 [PATCH 1/1] net: phy: marvell: avoid bringing down fibre link when autoneg is bypassed

[Mateusz Polchlopek]

On 10/3/2024 9:14 AM, Qingtao Cao wrote:
> Hi Mateusz,
>
> Please see my inline relies.
>
> On Thu, Oct 3, 2024 at 4:54 PM Mateusz Polchlopek 
> <mateusz.polchlopek@xxxxxxxxx <mailto:mateusz.polchlopek@xxxxxxxxx>> wrote:
>
>
>     On 10/3/2024 6:45 AM, Qingtao Cao wrote:
>      > On 88E151x the SGMII autoneg bypass mode defaults to be enabled.
>     When it is
>      > activated, the device assumes a link-up status with existing
>     configuration
>      > in BMCR, avoid bringing down the fibre link in this case
>      >
>      > Test case:
>      > 1. Two 88E151x connected with SFP, both enable autoneg, link is
>     up with speed
>      >     1000M
>
>     checkpatch.pl <http://checkpatch.pl> complains about this line, it
>     exceeds 75 chars allowed for
>     commit msg. Please adjust.
>
>      > 2. Disable autoneg on one device and explicitly set its speed to
>     1000M
>      > 3. The fibre link can still up with this change, otherwise not.
>      >
>      > Signed-off-by: Qingtao Cao <qingtao.cao@xxxxxxxx
>     <mailto:qingtao.cao@xxxxxxxx>>
>      > ---
>      >   drivers/net/phy/marvell.c | 23 ++++++++++++++++++++++-
>      >   1 file changed, 22 insertions(+), 1 deletion(-)
>      >
>      > diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
>      > index 9964bf3dea2f..e3a8ad8b08dd 100644
>      > --- a/drivers/net/phy/marvell.c
>      > +++ b/drivers/net/phy/marvell.c
>      > @@ -195,6 +195,10 @@
>      >
>      >   #define MII_88E1510_MSCR_2          0x15
>      >
>      > +#define MII_88E1510_FSCR2            0x1a
>
>     Please use GENMASK_ULL for creating mask.
>
>
> The serial interface autoneg bypass mode and active status are just two 
> separate bit in the FSCR2 register, instead of complicated masks, so I 
> think BIT() serves them right.

Ach, sorry, the GENMASK_ULL usage is not applicable here.

>      > +#define MII_88E1510_FSCR2_BYPASS_ENABLE      BIT(6)
>      > +#define MII_88E1510_FSCR2_BYPASS_STATUS      BIT(5)
>      > +
>      >   #define MII_VCT5_TX_RX_MDI0_COUPLING        0x10
>      >   #define MII_VCT5_TX_RX_MDI1_COUPLING        0x11
>      >   #define MII_VCT5_TX_RX_MDI2_COUPLING        0x12
>      > @@ -1623,11 +1627,28 @@ static void
>     fiber_lpa_mod_linkmode_lpa_t(unsigned long *advertising, u32 lpa)
>      >   static int marvell_read_status_page_an(struct phy_device *phydev,
>      >                                      int fiber, int status)
>      >   {
>      > +     int fscr2;
>      >       int lpa;
>      >       int err;
>      >
>      >       if (!(status & MII_M1011_PHY_STATUS_RESOLVED)) {
>      > -             phydev->link = 0;
>      > +             if (!fiber) {
>      > +                     phydev->link = 0;
>      > +             } else {
>      > +                     fscr2 = phy_read(phydev, MII_88E1510_FSCR2);
>      > +                     if (fscr2 > 0) {
>      > +                             if ((fscr2 &
>     MII_88E1510_FSCR2_BYPASS_ENABLE) &&
>      > +                                 (fscr2 &
>     MII_88E1510_FSCR2_BYPASS_STATUS)) {
>      > +                                     if
>     (genphy_read_status_fixed(phydev) < 0)
>      > +                                             phydev->link = 0;
>      > +                             } else {
>      > +                                     phydev->link = 0;
>      > +                             }
>      > +                     } else {
>      > +                             phydev->link = 0;
>      > +                     }
>      > +             }
>      > +
>      >               return 0;
>      >       }
>      >
>
>     So many levels of indentation... Couldn't it be merged somehow? I do not
>     know, maybe create local variable, store the current state of
>     phydev->link, then set phydev->link = 0 and restore it from local
>     variable only if (fiber && fscr2 > 0 && (fscr2 &
>     MII_88E1510_FSCR2_BYPASS_ENABLE) && (fscr2 &
>     MII_88E1510_FSCR2_BYPASS_STATUS) && genphy_read_status_fixed(phydev)
>      >=0
>     ) ...
>
>     or other way? Now you have 5 (!) levels of indentation and almost
>     everywhere you just set phydev->link to 0 depends on the condition.
>
>
> Thanks for the feedback, please check the v3 patch just sent.

I will take a look but a general rule is to wait a little bit longer (at
least two working days?) before sending next version of patch. It is
mainly to give a chance for taking a look by others. Thanks

>     BTW. We put "v2" inside the tag in the topic and specify the tree, so
>     instead of:
>     v2 [PATCH 1/1] net: phy: marvell: avoid bringing down fibre link when
>     autoneg is bypassed
>
>     it should be:
>     [PATCH net-next v2 1/1] net: phy: marvell: avoid bringing down fibre
>     link when autoneg is bypassed
>
>
> Thanks again, also improved in the v3 patch header.
>
> Warm regards,
> Qingtao