Re: [PATCH net-next 00/19] net: phy: add support for shared interrupts (part 1)

[Ioana Ciornei <ciorneiioana@gmail.com>]

On Sat, Oct 31, 2020 at 11:18:18AM +0100, Heiner Kallweit wrote:
> On 31.10.2020 00:36, 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)
> >>
> >> Here I have a concern, bits may be set even if the respective interrupt
> >> source isn't enabled. Therefore we may falsely blame a device to have
> >> triggered the interrupt. irq_status should be masked with the actually
> >> enabled irq source bits.
> > 
> > Hi Heiner
> > 
> Hi Andrew,
> 
> > I would say that is a driver implementation detail, for each driver to
> > handle how it needs to handle it. I've seen some hardware where the
> > interrupt status is already masked with the interrupt enabled
> > bits. I've soon other hardware where it is not.
> > 
> Sure, I just wanted to add the comment before others simply copy and
> paste this (pseudo) code. And in patch 9 (aquantia) and 18 (realtek)
> it is used as is. And IIRC at least the Aquantia PHY doesn't mask
> the interrupt status.
> 

Hi Heiner,

If I understand correctly what you are suggesting, the
.handle_interrupt() for the aquantia would look like this:

static irqreturn_t aqr_handle_interrupt(struct phy_device *phydev)
{
	int irq_status;

	irq_status = phy_read_mmd(phydev, MDIO_MMD_AN, MDIO_AN_TX_VEND_INT_STATUS2);
	if (irq_status < 0) {
		phy_error(phydev);
		return IRQ_NONE;
	}

	if (!(irq_status & MDIO_AN_TX_VEND_INT_STATUS2_MASK))
		return IRQ_NONE;

	phy_trigger_machine(phydev);

	return IRQ_HANDLED;
}

So only return IRQ_HANDLED when one of the bits from INT_STATUS
corresponding with the enabled interrupts are set, not if any other link
status bit is set.

Ok, I'll send a v2 with these kind of changes.

Ioana