netdev - Re: [PATCH v2] bcm63xx_enet: fix internal phy IRQ assignment

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Date:   Thu, 25 Feb 2021 08:22:22 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Daniel González Cabanelas <dgcbueu@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>
Cc:     "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 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()?.

On which kernel version do you face this problem?

> Regards
>> --
>> Florian