Re: [PATCH net-next 2/3] net: ethernet: oa_tc6: deliver the PHY interrupt to phylib

On 03/09/26 7:24 pm, Andrew Lunn wrote:

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On Thu, Sep 03, 2026 at 06:32:26PM +0530, Parthiban Veerasooran wrote:

quoted

Hi Andrew,

Thank you for reviewing this patch series.

On 02/09/26 6:13 am, Andrew Lunn wrote:

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On Tue, Sep 01, 2026 at 06:39:47PM +0530, Parthiban Veerasooran wrote:

quoted

The integrated PHY has no dedicated interrupt line; its interrupt is
delivered in-band as the PHYINT bit in STATUS0, which raises the MAC-PHY
SPI interrupt via the extended status. phy_mac_interrupt() only triggers
a link-status re-read and cannot make the PHY driver read and acknowledge
its interrupt source registers, so expose the PHY interrupt to phylib as a
nested virtual IRQ instead.

Use dummy_irq_chip as the irqchip, map a virtual IRQ and assign it to
phydev->irq before phy_connect_direct() so phylib enters interrupt mode
and uses the PHY driver's config_intr/handle_interrupt. Unmask PHYINT in
INT_MASK0, and when it is seen in the extended status, dispatch
handle_nested_irq() synchronously from the sleepable threaded IRQ. PHYINT
is level triggered, so acking the PHY source there clears it before the
next data chunk, avoiding a storm.

     9.2.8.7 PHYINT

     Physical Layer Interrupt. When set, this bit indicates a service
     request from the underlying physical layer block.  Many physical
     layer implementations support an interrupt output for signaling
     events to the station controller. This bit is optional and will be
     implemented only if the underlying physical layer supports
     generating interrupts to a higher level. When implemented, this bit
     shall be cleared by acknowledging the underlying physical layer
     interrupt source(s). When not implemented, this bit shall be
     reserved with a read- only value of zero.

At the moment, phylib is polling the PHY. That is guaranteed to work.

The standard indicates this interrupt is optional. It might not be
implemented. phylib assumes that if there is an interrupt, the
interrupt works, and it does not poll. So any hardware which does not
implement this interrupt is now broken.

Please find a way not to break other devices.

Thank you for pointing it out. PHYINT is optional per the OA TC6 standard
(section 9.2.8.7), and unconditionally setting up the virtual IRQ breaks
devices that do not implement it.

I checked both the OA TC6 standard (V1.1) and the LAN8650/1 datasheet, and
there is no capability register bit to detect PHYINT support at runtime.

I also did a quick check of the standard and could not find an
indication if interrupts were support. So a quirks flag does seem to
be the correct solution.

Thank you for the confirmation. I will implement it in the next version.

Best regards,
Parthiban V>

    Andrew