Message-ID: <c9e72b62-3b4e-6214-f807-b24ec506cb56@gmail.com>
Date:   Fri, 26 Feb 2021 10:32:44 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Daniel González Cabanelas <dgcbueu@...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

On 26.02.2021 10:10, Daniel González Cabanelas wrote:
> 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)

Is this an out-of-tree driver? I can't find this string in any
DSA or PHY driver.


> [    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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