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[net-next,1/3] net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM

Message ID cd2c3325-d742-29a7-9310-899bec0061ca@gmail.com (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series net: make PHY PM ops a no-op if MAC driver manages PHY PM | expand


Context Check Description
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netdev/tree_selection success Clearly marked for net-next
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netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 637 this patch: 637
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 32 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 553 this patch: 553
netdev/header_inline success Link

Commit Message

Heiner Kallweit April 7, 2021, 3:51 p.m. UTC
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>
 drivers/net/phy/phy_device.c | 6 ++++++
 include/linux/phy.h          | 2 ++
 2 files changed, 8 insertions(+)
diff mbox series


diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index a009d1769..73d29fd5e 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 8e2cf84b2..98fb441dd 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 */