Date:   Fri, 26 Feb 2021 10:10:31 +0100
From:   Daniel González Cabanelas <dgcbueu@...il.com>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, gregkh@...uxfoundation.org,
        netdev@...r.kernel.org,
        Álvaro Fernández Rojas <noltari@...il.com>
Subject: Re: [PATCH v2] bcm63xx_enet: fix internal phy IRQ assignment

El vie, 26 feb 2021 a las 8:13, Heiner Kallweit
(<hkallweit1@...il.com>) escribió:
>
> On 25.02.2021 23:28, Daniel González Cabanelas wrote:
> > El jue, 25 feb 2021 a las 21:05, Heiner Kallweit
> > (<hkallweit1@...il.com>) escribió:
> >>
> >> On 25.02.2021 17:36, Daniel González Cabanelas wrote:
> >>> El jue, 25 feb 2021 a las 8:22, Heiner Kallweit
> >>> (<hkallweit1@...il.com>) escribió:
> >>>>
> >>>> On 25.02.2021 00:54, Daniel González Cabanelas wrote:
> >>>>> El mié, 24 feb 2021 a las 23:01, Florian Fainelli
> >>>>> (<f.fainelli@...il.com>) escribió:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> On 2/24/2021 1:44 PM, Heiner Kallweit wrote:
> >>>>>>> On 24.02.2021 16:44, Daniel González Cabanelas wrote:
> >>>>>>>> The current bcm63xx_enet driver doesn't asign the internal phy IRQ. As a
> >>>>>>>> result of this it works in polling mode.
> >>>>>>>>
> >>>>>>>> Fix it using the phy_device structure to assign the platform IRQ.
> >>>>>>>>
> >>>>>>>> Tested under a BCM6348 board. Kernel dmesg before the patch:
> >>>>>>>>    Broadcom BCM63XX (1) bcm63xx_enet-0:01: attached PHY driver [Broadcom
> >>>>>>>>               BCM63XX (1)] (mii_bus:phy_addr=bcm63xx_enet-0:01, irq=POLL)
> >>>>>>>>
> >>>>>>>> After the patch:
> >>>>>>>>    Broadcom BCM63XX (1) bcm63xx_enet-0:01: attached PHY driver [Broadcom
> >>>>>>>>               BCM63XX (1)] (mii_bus:phy_addr=bcm63xx_enet-0:01, irq=17)
> >>>>>>>>
> >>>>>>>> Pluging and uplugging the ethernet cable now generates interrupts and the
> >>>>>>>> PHY goes up and down as expected.
> >>>>>>>>
> >>>>>>>> Signed-off-by: Daniel González Cabanelas <dgcbueu@...il.com>
> >>>>>>>> ---
> >>>>>>>> changes in V2:
> >>>>>>>>   - snippet moved after the mdiobus registration
> >>>>>>>>   - added missing brackets
> >>>>>>>>
> >>>>>>>>  drivers/net/ethernet/broadcom/bcm63xx_enet.c | 13 +++++++++++--
> >>>>>>>>  1 file changed, 11 insertions(+), 2 deletions(-)
> >>>>>>>>
> >>>>>>>> diff --git a/drivers/net/ethernet/broadcom/bcm63xx_enet.c b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
> >>>>>>>> index fd876721316..dd218722560 100644
> >>>>>>>> --- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
> >>>>>>>> +++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
> >>>>>>>> @@ -1818,10 +1818,19 @@ static int bcm_enet_probe(struct platform_device *pdev)
> >>>>>>>>               * if a slave is not present on hw */
> >>>>>>>>              bus->phy_mask = ~(1 << priv->phy_id);
> >>>>>>>>
> >>>>>>>> -            if (priv->has_phy_interrupt)
> >>>>>>>> +            ret = mdiobus_register(bus);
> >>>>>>>> +
> >>>>>>>> +            if (priv->has_phy_interrupt) {
> >>>>>>>> +                    phydev = mdiobus_get_phy(bus, priv->phy_id);
> >>>>>>>> +                    if (!phydev) {
> >>>>>>>> +                            dev_err(&dev->dev, "no PHY found\n");
> >>>>>>>> +                            goto out_unregister_mdio;
> >>>>>>>> +                    }
> >>>>>>>> +
> >>>>>>>>                      bus->irq[priv->phy_id] = priv->phy_interrupt;
> >>>>>>>> +                    phydev->irq = priv->phy_interrupt;
> >>>>>>>> +            }
> >>>>>>>>
> >>>>>>>> -            ret = mdiobus_register(bus);
> >>>>>>>
> >>>>>>> You shouldn't have to set phydev->irq, this is done by phy_device_create().
> >>>>>>> For this to work bus->irq[] needs to be set before calling mdiobus_register().
> >>>>>>
> >>>>>> Yes good point, and that is what the unchanged code does actually.
> >>>>>> Daniel, any idea why that is not working?
> >>>>>
> >>>>> Hi Florian, I don't know. bus->irq[] has no effect, only assigning the
> >>>>> IRQ through phydev->irq works.
> >>>>>
> >>>>> I can resend the patch  without the bus->irq[] line since it's
> >>>>> pointless in this scenario.
> >>>>>
> >>>>
> >>>> It's still an ugly workaround and a proper root cause analysis should be done
> >>>> first. I can only imagine that phydev->irq is overwritten in phy_probe()
> >>>> because phy_drv_supports_irq() is false. Can you please check whether
> >>>> phydev->irq is properly set in phy_device_create(), and if yes, whether
> >>>> it's reset to PHY_POLL in phy_probe()?.
> >>>>
> >>>
> >>> Hi Heiner, I added some kernel prints:
> >>>
> >>> [    2.712519] libphy: Fixed MDIO Bus: probed
> >>> [    2.721969] =======phy_device_create===========
> >>> [    2.726841] phy_device_create: dev->irq = 17
> >>> [    2.726841]
> >>> [    2.832620] =======phy_probe===========
> >>> [    2.836846] phy_probe: phydev->irq = 17
> >>> [    2.840950] phy_probe: phy_drv_supports_irq = 0, phy_interrupt_is_valid = 1
> >>> [    2.848267] phy_probe: phydev->irq = -1
> >>> [    2.848267]
> >>> [    2.854059] =======phy_probe===========
> >>> [    2.858174] phy_probe: phydev->irq = -1
> >>> [    2.862253] phy_probe: phydev->irq = -1
> >>> [    2.862253]
> >>> [    2.868121] libphy: bcm63xx_enet MII bus: probed
> >>> [    2.873320] Broadcom BCM63XX (1) bcm63xx_enet-0:01: attached PHY
> >>> driver [Broadcom BCM63XX (1)] (mii_bus:phy_addr=bcm63xx_enet-0:01,
> >>> irq=POLL)
> >>>
> >>> Currently using kernel 5.4.99. I still have no idea what's going on.
> >>>
> >> Thanks for debugging. This confirms my assumption that the interrupt
> >> is overwritten in phy_probe(). I'm just scratching my head how
> >> phy_drv_supports_irq() can return 0. In 5.4.99 it's defined as:
> >>
> >> static bool phy_drv_supports_irq(struct phy_driver *phydrv)
> >> {
> >>         return phydrv->config_intr && phydrv->ack_interrupt;
> >> }
> >>
> >> And that's the PHY driver:
> >>
> >> static struct phy_driver bcm63xx_driver[] = {
> >> {
> >>         .phy_id         = 0x00406000,
> >>         .phy_id_mask    = 0xfffffc00,
> >>         .name           = "Broadcom BCM63XX (1)",
> >>         /* PHY_BASIC_FEATURES */
> >>         .flags          = PHY_IS_INTERNAL,
> >>         .config_init    = bcm63xx_config_init,
> >>         .ack_interrupt  = bcm_phy_ack_intr,
> >>         .config_intr    = bcm63xx_config_intr,
> >> }
> >>
> >> So both callbacks are set. Can you extend your debugging and check
> >> in phy_drv_supports_irq() which of the callbacks is missing?
> >>
> >
> > Hi, both callbacks are missing on the first check. However on the next
> > calls they're there.
> >
> > [    2.263909] libphy: Fixed MDIO Bus: probed
> > [    2.273026] =======phy_device_create===========
> > [    2.277908] phy_device_create: dev->irq = 17
> > [    2.277908]
> > [    2.373104] =======phy_probe===========
> > [    2.377336] phy_probe: phydev->irq = 17
> > [    2.381445] phy_drv_supports_irq: phydrv->config_intr = 0,
> > phydrv->ack_interrupt = 0
> > [    2.389554] phydev->irq = PHY_POLL;
> > [    2.393186] phy_probe: phydev->irq = -1
> > [    2.393186]
> > [    2.398987] =======phy_probe===========
> > [    2.403108] phy_probe: phydev->irq = -1
> > [    2.407195] phy_drv_supports_irq: phydrv->config_intr = 1,
> > phydrv->ack_interrupt = 1
> > [    2.415314] phy_probe: phydev->irq = -1
> > [    2.415314]
> > [    2.421189] libphy: bcm63xx_enet MII bus: probed
> > [    2.426129] =======phy_connect===========
> > [    2.430410] phy_drv_supports_irq: phydrv->config_intr = 1,
> > phydrv->ack_interrupt = 1
> > [    2.438537] phy_connect: phy_drv_supports_irq = 1
> > [    2.438537]
> > [    2.445284] Broadcom BCM63XX (1) bcm63xx_enet-0:01: attached PHY
> > driver [Broadcom BCM63XX (1)] (mii_bus:phy_addr=bcm63xx_enet-0:01,
> > irq=POLL)
> >
>
> I'd like to understand why the phy_device is probed twice,
> with which drivers it's probed.
> Could you please add printing phydrv->name to phy_probe() ?
>

Hi Heiner, indeed there are two different probed devices. The B53
switch driver is causing this issue.

[    2.269595] libphy: Fixed MDIO Bus: probed
[    2.278706] =======phy_device_create===========
[    2.283594] phy_device_create: dev->irq = 17
[    2.283594]
[    2.379554] =======phy_probe===========
[    2.383780] phy_probe: phydrv->name = Broadcom B53 (3)
[    2.389235] phy_probe: phydev->irq = 17
[    2.393332] phy_drv_supports_irq: phydrv->config_intr = 0,
phydrv->ack_interrupt = 0
[    2.401445] phydev->irq = PHY_POLL
[    2.405080] phy_probe: phydev->irq = -1
[    2.405080]
[    2.410878] =======phy_probe===========
[    2.414996] phy_probe: phydrv->name = Broadcom BCM63XX (1)
[    2.420791] phy_probe: phydev->irq = -1
[    2.424876] phy_drv_supports_irq: phydrv->config_intr = 1,
phydrv->ack_interrupt = 1
[    2.432994] phy_probe: phydev->irq = -1
[    2.432994]
[    2.438862] libphy: bcm63xx_enet MII bus: probed
[    2.443809] =======phy_connect===========
[    2.448092] phy_drv_supports_irq: phydrv->config_intr = 1,
phydrv->ack_interrupt = 1
[    2.456215] phy_connect: phy_drv_supports_irq = 1
[    2.456215]
[    2.462961] Broadcom BCM63XX (1) bcm63xx_enet-0:01: attached PHY
driver [Broadcom BCM63XX (1)] (mii_bus:phy_addr=bcm63xx_enet-0:01,
irq=POLL)

The board has no switch, it's a driver for other boards in OpenWrt. I
forgot it wasn't upstreamed:
https://github.com/openwrt/openwrt/tree/master/target/linux/generic/files/drivers/net/phy/b53

I tested a kernel compiled without this driver, now the IRQ is
detected as it should be:

[    2.270707] libphy: Fixed MDIO Bus: probed
[    2.279715] =======phy_device_create===========
[    2.284600] phy_device_create: dev->irq = 17
[    2.284600]
[    2.373763] =======phy_probe===========
[    2.377989] phy_probe: phydrv->name = Broadcom BCM63XX (1)
[    2.383803] phy_probe: phydev->irq = 17
[    2.387888] phy_drv_supports_irq: phydrv->config_intr = 1,
phydrv->ack_interrupt = 1
[    2.396007] phy_probe: phydev->irq = 17
[    2.396007]
[    2.401877] libphy: bcm63xx_enet MII bus: probed
[    2.406820] =======phy_connect===========
[    2.411099] phy_drv_supports_irq: phydrv->config_intr = 1,
phydrv->ack_interrupt = 1
[    2.419226] phy_connect: phy_drv_supports_irq = 1
[    2.419226]
[    2.429857] Broadcom BCM63XX (1) bcm63xx_enet-0:01: attached PHY
driver [Broadcom BCM63XX (1)] (mii_bus:phy_addr=bcm63xx_enet-0:01,
irq=17)

Then, maybe this is an OpenWrt bug itself?

Regards
Daniel

>
> > I also added the prints to phy_connect.
> >
> >> Last but not least: Do you use a mainline kernel, or is it maybe
> >> a modified downstream kernel? In the latter case, please check
> >> in your kernel sources whether both callbacks are set.
> >>
> >
> > It's a modified kernel, and the the callbacks are set. BTW I also
> > tested the kernel with no patches concerning to the ethernet driver.
> >
> > Regards,
> > Daniel
> >
> >>
> >>
> >>>> On which kernel version do you face this problem?
> >>>>
> >>> The kernel version 4.4 works ok. The minimum version where I found the
> >>> problem were the kernel 4.9.111, now using 5.4. And 5.10 also tested.
> >>>
> >>> Regards
> >>> Daniel
> >>>
> >>>>> Regards
> >>>>>> --
> >>>>>> Florian
> >>>>
> >>
>

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