Re: [PATCH] net: phy: Don't disable irqs on shutdown if WoL is enabled

On Wed, Aug 09, 2023 at 06:44:18PM +0300, Ioana Ciornei wrote:

On Wed, Aug 09, 2023 at 03:29:17PM +0100, Russell King (Oracle) wrote:

quoted

On Wed, Aug 09, 2023 at 05:21:55PM +0300, Ioana Ciornei wrote:

quoted

That's a perfect summary of the problem that I was trying to fix.

The board in question is a LS1021ATSN which has two AR8031 PHYs that
share an interrupt line. In case only one of the PHYs is probed and
there are pending interrupts on the PHY#2 an IRQ storm will happen
since there is no entity to clear the interrupt from PHY#2's registers.
PHY#1's driver will get stuck in .handle_interrupt() indefinitely.

So I have two further questions:
1. Is WoL able to be supported on this hardware?

I don't know if anyone cares about WoL on the AR8031 PHYs from this
board.

Both of the PHYs are used in conjuction with 2 eTSEC controllers - which
use the driver in drivers/net/ethernet/freescale/gianfar.c.

The Ethernet controller does have WoL support, which means that WoL could
still be supported on the board even though we would forbid WoL on the
AR8031 PHYs.

quoted

2. AR8031 has a seperate WOL_INT signal that can be used to wake up the
   system. Is this used in the hardware design?

No, WOL_INT is not connected.

Okay, so we don't need to care about WoL for your hardware setup.

Thinking about this, I wonder whether we could solve your issue by
disabling interrupts when the PHY is probed, rather than disabling
them on shutdown - something like this? (not build tested)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 3e9909b30938..4d1a37487923 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c

@@ -3216,6 +3216,8 @@ static int phy_probe(struct device *dev)
 			goto out;
 	}
 
+        phy_disable_interrupts(phydev);
+
 	/* Start out supporting everything. Eventually,
 	 * a controller will attach, and may modify one
 	 * or both of these values

@@ -3333,16 +3335,6 @@ static int phy_remove(struct device *dev)
 	return 0;
 }
 
-static void phy_shutdown(struct device *dev)
-{
-	struct phy_device *phydev = to_phy_device(dev);
-
-	if (phydev->state == PHY_READY || !phydev->attached_dev)
-		return;
-
-	phy_disable_interrupts(phydev);
-}
-
 /**
  * phy_driver_register - register a phy_driver with the PHY layer
  * @new_driver: new phy_driver to register

@@ -3376,7 +3368,6 @@ int phy_driver_register(struct phy_driver *new_driver, struct module *owner)
 	new_driver->mdiodrv.driver.bus = &mdio_bus_type;
 	new_driver->mdiodrv.driver.probe = phy_probe;
 	new_driver->mdiodrv.driver.remove = phy_remove;
-	new_driver->mdiodrv.driver.shutdown = phy_shutdown;
 	new_driver->mdiodrv.driver.owner = owner;
 	new_driver->mdiodrv.driver.probe_type = PROBE_FORCE_SYNCHRONOUS;
 

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