From fba863b816049b03f3fbb07b10ebdcfe5c4141f7 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Wed, 7 Apr 2021 17:51:56 +0200 Subject: [PATCH] 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: Heiner Kallweit Signed-off-by: Jakub Kicinski --- 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 a009d1769b08..73d29fd5e03d 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 8e2cf84b2318..98fb441dd72e 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 */