Re: [RFC net-next 0/5] net: phy: add support for shared interrupts

[Ioana Ciornei]

On Sat, Oct 24, 2020 at 07:17:05PM +0200, Andrew Lunn wrote:
> > - Every PHY driver gains a .handle_interrupt() implementation that, for
> >   the most part, would look like below:
> > 
> > 	irq_status = phy_read(phydev, INTR_STATUS);
> > 	if (irq_status < 0) {
> > 		phy_error(phydev);
> > 		return IRQ_NONE;
> > 	}
> > 
> > 	if (irq_status == 0)
> > 		return IRQ_NONE;
> > 
> > 	phy_trigger_machine(phydev);
> > 
> > 	return IRQ_HANDLED;
> 
> Hi Ioana
> 
> It looks like phy_trigger_machine(phydev) could be left in the core,
> phy_interrupt(). It just needs to look at the return code, IRQ_HANDLED
> means trigger the state machine.

I tend to disagree that this would bring us any benefit.

Keeping the phy_trigger_machine() inside the phy_interrupt() would mean
that we are changing the convention of what the implementation of
.handle_interrupt() should do.

At the moment, there are drivers which use it to handle multiple
interrupt sources within the same PHY device (e.g. MACSEC, 1588, link
state). With your suggestion, when a MACSEC interrupt is received, the
PHY driver would be forced to return IRQ_NONE just so phylib does not
trigger the link state machine. I think this would eventually lead to
some "irq X: nobody cared".

Also, the vsc8584_handle_interrupt() already calls a wrapper over
phy_trigger_machine() called phy_mac_interrupt() which was intended for
MAC driver use only.

Ioana