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

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@intel.com <mailto:mateusz.polchlopek@intel.com>> 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@digi.com
    <mailto:qingtao.cao@digi.com>>
     > ---
     >   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