Commit fba863b8 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Jakub Kicinski
Browse files

net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM 



Resume callback of the PHY driver is called after the one for the MAC
driver. The PHY driver resume callback calls phy_init_hw(), and this is
potentially problematic if the MAC driver calls phy_start() in its resume
callback. One issue was reported with the fec driver and a KSZ8081 PHY
which seems to become unstable if a soft reset is triggered during aneg.

The new flag allows MAC drivers to indicate that they take care of
suspending/resuming the PHY. Then the MAC PM callbacks can handle
any dependency between MAC and PHY PM.

Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a7150e38

drivers/net/phy/phy_device.c

+6 −0
Original line number Diff line number Diff line
@@ -273,6 +273,9 @@ static __maybe_unused int mdio_bus_phy_suspend(struct device *dev) 
{

	struct phy_device *phydev = to_phy_device(dev);



	if (phydev->mac_managed_pm)

		return 0;



	/* We must stop the state machine manually, otherwise it stops out of

	 * control, possibly with the phydev->lock held. Upon resume, netdev

	 * may call phy routines that try to grab the same lock, and that may
@@ -294,6 +297,9 @@ static __maybe_unused int mdio_bus_phy_resume(struct device *dev) 
	struct phy_device *phydev = to_phy_device(dev);

	int ret;



	if (phydev->mac_managed_pm)

		return 0;



	if (!phydev->suspended_by_mdio_bus)

		goto no_resume;

include/linux/phy.h

+2 −0
Original line number Diff line number Diff line
@@ -493,6 +493,7 @@ struct macsec_ops; 
 * @loopback_enabled: Set true if this PHY has been loopbacked successfully.

 * @downshifted_rate: Set true if link speed has been downshifted.

 * @is_on_sfp_module: Set true if PHY is located on an SFP module.

 * @mac_managed_pm: Set true if MAC driver takes of suspending/resuming PHY

 * @state: State of the PHY for management purposes

 * @dev_flags: Device-specific flags used by the PHY driver.

 * @irq: IRQ number of the PHY's interrupt (-1 if none)
@@ -567,6 +568,7 @@ struct phy_device { 
	unsigned loopback_enabled:1;

	unsigned downshifted_rate:1;

	unsigned is_on_sfp_module:1;

	unsigned mac_managed_pm:1;



	unsigned autoneg:1;

	/* The most recently read link state */