linux-stable.git/drivers/net/phy/phy_device.c, branch linux-6.16.y

net: phy: Don't register LEDs for genphy

2025-07-15T00:53:09+00:00

If a PHY has no driver, the genphy driver is probed/removed directly in
phy_attach/detach. If the PHY's ofnode has an "leds" subnode, then the
LEDs will be (un)registered when probing/removing the genphy driver.
This could occur if the leds are for a non-generic driver that isn't
loaded for whatever reason. Synchronously removing the PHY device in
phy_detach leads to the following deadlock:

rtnl_lock()
ndo_close()
    ...
    phy_detach()
        phy_remove()
            phy_leds_unregister()
                led_classdev_unregister()
                    led_trigger_set()
                        netdev_trigger_deactivate()
                            unregister_netdevice_notifier()
                                rtnl_lock()

There is a corresponding deadlock on the open/register side of things
(and that one is reported by lockdep), but it requires a race while this
one is deterministic.

Generic PHYs do not support LEDs anyway, so don't bother registering
them.

Fixes: 01e5b728e9e4 ("net: phy: Add a binding for PHY LEDs")
Signed-off-by: Sean Anderson 
Link: https://patch.msgid.link/20250707195803.666097-1-sean.anderson@linux.dev
Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-05-28T08:11:15+00:00

Merge in late fixes to prepare for the 6.16 net-next PR.

No conflicts nor adjacent changes.

Signed-off-by: Paolo Abeni

net: phy: clear phydev->devlink when the link is deleted

2025-05-28T00:10:25+00:00

There is a potential crash issue when disabling and re-enabling the
network port. When disabling the network port, phy_detach() calls
device_link_del() to remove the device link, but it does not clear
phydev->devlink, so phydev->devlink is not a NULL pointer. Then the
network port is re-enabled, but if phy_attach_direct() fails before
calling device_link_add(), the code jumps to the "error" label and
calls phy_detach(). Since phydev->devlink retains the old value from
the previous attach/detach cycle, device_link_del() uses the old value,
which accesses a NULL pointer and causes a crash. The simplified crash
log is as follows.

[   24.702421] Call trace:
[   24.704856]  device_link_put_kref+0x20/0x120
[   24.709124]  device_link_del+0x30/0x48
[   24.712864]  phy_detach+0x24/0x168
[   24.716261]  phy_attach_direct+0x168/0x3a4
[   24.720352]  phylink_fwnode_phy_connect+0xc8/0x14c
[   24.725140]  phylink_of_phy_connect+0x1c/0x34

Therefore, phydev->devlink needs to be cleared when the device link is
deleted.

Fixes: bc66fa87d4fd ("net: phy: Add link between phy dev and mac dev")
Signed-off-by: Wei Fang 
Reviewed-by: Andrew Lunn 
Reviewed-by: Florian Fainelli 
Link: https://patch.msgid.link/20250523083759.3741168-1-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski

net: phy: introduce genphy_match_phy_device()

2025-05-21T22:56:10+00:00

Introduce new API, genphy_match_phy_device(), to provide a way to check
to match a PHY driver for a PHY device based on the info stored in the
PHY device struct.

The function generalize the logic used in phy_bus_match() to check the
PHY ID whether if C45 or C22 ID should be used for matching.

This is useful for custom .match_phy_device function that wants to use
the generic logic under some condition. (example a PHY is already setup
and provide the correct PHY ID)

Reviewed-by: Russell King (Oracle) 
Signed-off-by: Christian Marangi 
Link: https://patch.msgid.link/20250517201353.5137-5-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski

net: phy: pass PHY driver to .match_phy_device OP

2025-05-21T22:56:09+00:00

Pass PHY driver pointer to .match_phy_device OP in addition to phydev.
Having access to the PHY driver struct might be useful to check the
PHY ID of the driver is being matched for in case the PHY ID scanned in
the phydev is not consistent.

A scenario for this is a PHY that change PHY ID after a firmware is
loaded, in such case, the PHY ID stored in PHY device struct is not
valid anymore and PHY will manually scan the ID in the match_phy_device
function.

Having the PHY driver info is also useful for those PHY driver that
implement multiple simple .match_phy_device OP to match specific MMD PHY
ID. With this extra info if the parsing logic is the same, the matching
function can be generalized by using the phy_id in the PHY driver
instead of hardcoding.

Rust wrapper callback is updated to align to the new match_phy_device
arguments.

Suggested-by: Russell King (Oracle) 
Reviewed-by: Russell King (Oracle) 
Signed-off-by: Christian Marangi 
Reviewed-by: Benno Lossin  # for Rust
Reviewed-by: FUJITA Tomonori 
Link: https://patch.msgid.link/20250517201353.5137-2-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski

net: phy: make mdio consumer / device layer a separate module

2025-05-20T10:22:47+00:00

After having factored out the provider part from mdio_bus.c, we can
make the mdio consumer / device layer a separate module. This also
allows to remove Kconfig symbol MDIO_DEVICE.
The module init / exit functions from mdio_bus.c no longer have to be
called from phy_device.c. The link order defined in
drivers/net/phy/Makefile ensures that init / exit functions are called
in the right order.

Signed-off-by: Heiner Kallweit 
Link: https://patch.msgid.link/dba6b156-5748-44ce-b5e2-e8dc2fcee5a7@gmail.com
Signed-off-by: Paolo Abeni

net: phy: Refactor fwnode_get_phy_node()

2025-05-05T23:50:26+00:00

Refactor to check if the fwnode we got is correct and return if so,
otherwise do additional checks. Using same pattern in all conditionals
makes it slightly easier to read and understand.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20250430143802.3714405-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jakub Kicinski

net: phy: Add helper for getting MAC termination resistance

2025-04-23T00:49:48+00:00

Add helper which returns the MAC termination resistance value. Modifying
the resistance to an appropriate value can reduce signal reflections and
therefore improve signal quality.

Reviewed-by: Russell King (Oracle) 
Signed-off-by: Dimitri Fedrau 
Link: https://patch.msgid.link/20250416-dp83822-mac-impedance-v3-3-028ac426cddb@liebherr.com
Signed-off-by: Jakub Kicinski

net: phy: remove device_phy_find_device

2025-04-15T15:26:04+00:00

AFAICS this function has never had a user.

Signed-off-by: Heiner Kallweit 
Reviewed-by: Andrew Lunn 
Link: https://patch.msgid.link/ab7b8094-2eea-4e82-a047-fd60117f220b@gmail.com
Signed-off-by: Jakub Kicinski

net: phy: allow MDIO bus PM ops to start/stop state machine for phylink-controlled PHY

2025-04-10T00:56:08+00:00

DSA has 2 kinds of drivers:

1. Those who call dsa_switch_suspend() and dsa_switch_resume() from
   their device PM ops: qca8k-8xxx, bcm_sf2, microchip ksz
2. Those who don't: all others. The above methods should be optional.

For type 1, dsa_switch_suspend() calls dsa_user_suspend() -> phylink_stop(),
and dsa_switch_resume() calls dsa_user_resume() -> phylink_start().
These seem good candidates for setting mac_managed_pm = true because
that is essentially its definition [1], but that does not seem to be the
biggest problem for now, and is not what this change focuses on.

Talking strictly about the 2nd category of DSA drivers here (which
do not have MAC managed PM, meaning that for their attached PHYs,
mdio_bus_phy_suspend() and mdio_bus_phy_resume() should run in full),
I have noticed that the following warning from mdio_bus_phy_resume() is
triggered:

	WARN_ON(phydev->state != PHY_HALTED && phydev->state != PHY_READY &&
		phydev->state != PHY_UP);

because the PHY state machine is running.

It's running as a result of a previous dsa_user_open() -> ... ->
phylink_start() -> phy_start() having been initiated by the user.

The previous mdio_bus_phy_suspend() was supposed to have called
phy_stop_machine(), but it didn't. So this is why the PHY is in state
PHY_NOLINK by the time mdio_bus_phy_resume() runs.

mdio_bus_phy_suspend() did not call phy_stop_machine() because for
phylink, the phydev->adjust_link function pointer is NULL. This seems a
technicality introduced by commit fddd91016d16 ("phylib: fix PAL state
machine restart on resume"). That commit was written before phylink
existed, and was intended to avoid crashing with consumer drivers which
don't use the PHY state machine - phylink always does, when using a PHY.
But phylink itself has historically not been developed with
suspend/resume in mind, and apparently not tested too much in that
scenario, allowing this bug to exist unnoticed for so long. Plus, prior
to the WARN_ON(), it would have likely been invisible.

This issue is not in fact restricted to type 2 DSA drivers (according to
the above ad-hoc classification), but can be extrapolated to any MAC
driver with phylink and MDIO-bus-managed PHY PM ops. DSA is just where
the issue was reported. Assuming mac_managed_pm is set correctly, a
quick search indicates the following other drivers might be affected:

$ grep -Zlr PHYLINK_NETDEV drivers/ | xargs -0 grep -L mac_managed_pm
drivers/net/ethernet/atheros/ag71xx.c
drivers/net/ethernet/microchip/sparx5/sparx5_main.c
drivers/net/ethernet/microchip/lan966x/lan966x_main.c
drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
drivers/net/ethernet/freescale/ucc_geth.c
drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
drivers/net/ethernet/marvell/mvneta.c
drivers/net/ethernet/marvell/prestera/prestera_main.c
drivers/net/ethernet/mediatek/mtk_eth_soc.c
drivers/net/ethernet/altera/altera_tse_main.c
drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c
drivers/net/ethernet/meta/fbnic/fbnic_phylink.c
drivers/net/ethernet/tehuti/tn40_phy.c
drivers/net/ethernet/mscc/ocelot_net.c

Make the existing conditions dependent on the PHY device having a
phydev->phy_link_change() implementation equal to the default
phy_link_change() provided by phylib. Otherwise, we implicitly know that
the phydev has the phylink-provided phylink_phy_change() callback, and
when phylink is used, the PHY state machine always needs to be stopped/
started on the suspend/resume path. The code is structured as such that
if phydev->phy_link_change() is absent, it is a matter of time until the
kernel will crash - no need to further complicate the test.

Thus, for the situation where the PM is not managed by the MAC, we will
make the MDIO bus PM ops treat identically the phylink-controlled PHYs
with the phylib-controlled PHYs where an adjust_link() callback is
supplied. In both cases, the MDIO bus PM ops should stop and restart the
PHY state machine.

[1] https://lore.kernel.org/netdev/Z-1tiW9zjcoFkhwc@shell.armlinux.org.uk/

Fixes: 744d23c71af3 ("net: phy: Warn about incorrect mdio_bus_phy_resume() state")
Reported-by: Wei Fang 
Tested-by: Wei Fang 
Signed-off-by: Vladimir Oltean 
Link: https://patch.msgid.link/20250407094042.2155633-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski