From: Heiner Kallweit hkallweit1@gmail.com
[ Upstream commit fba863b816049b03f3fbb07b10ebdcfe5c4141f7 ]
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: Heiner Kallweit hkallweit1@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/phy/phy_device.c | 6 ++++++ include/linux/phy.h | 2 ++ 2 files changed, 8 insertions(+)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index cc38e326405a..af2e1759b523 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -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;
diff --git a/include/linux/phy.h b/include/linux/phy.h index 1a12e4436b5b..8644b097dea3 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -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 */