linux-stable.git/drivers/net/phy/phy_device.c, branch v6.15

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

net: phy: move phy_link_change() prior to mdio_bus_phy_may_suspend()

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

In an upcoming change, mdio_bus_phy_may_suspend() will need to
distinguish a phylib-based PHY client from a phylink PHY client.
For that, it will need to compare the phydev->phy_link_change() function
pointer with the eponymous phy_link_change() provided by phylib.

To avoid forward function declarations, the default PHY link state
change method should be moved upwards. There is no functional change
associated with this patch, it is only to reduce the noise from a real
bug fix.

Signed-off-by: Vladimir Oltean 
Reviewed-by: Russell King (Oracle) 
Link: https://patch.msgid.link/20250407093900.2155112-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski

net: phy: Support speed selection for PHY loopback

2025-03-20T07:45:08+00:00

phy_loopback() leaves it to the PHY driver to select the speed of the
loopback mode. Thus, the speed of the loopback mode depends on the PHY
driver in use.

Add support for speed selection to phy_loopback() to enable loopback
with defined speeds. Ensure that link up is signaled if speed changes
as speed is not allowed to change during link up. Link down and up is
necessary for a new speed.

Signed-off-by: Gerhard Engleder 
Link: https://patch.msgid.link/20250312203010.47429-3-gerhard@engleder-embedded.com
Signed-off-by: Paolo Abeni

net: phy: Allow loopback speed selection for PHY drivers

2025-03-20T07:45:08+00:00

PHY drivers support loopback mode, but it is not possible to select the
speed of the loopback mode. The speed is chosen by the set_loopback()
operation of the PHY driver. Same is valid for genphy_loopback().

There are PHYs that support loopback with different speeds. Extend
set_loopback() to make loopback speed selection possible.

Signed-off-by: Gerhard Engleder 
Reviewed-by: Andrew Lunn 
Link: https://patch.msgid.link/20250312203010.47429-2-gerhard@engleder-embedded.com
Signed-off-by: Paolo Abeni

net: phy: phy_device: Use link_capabilities lookup for PHY aneg config

2025-03-18T08:03:11+00:00

When configuring PHY advertising with autoneg disabled, we lookd for an
exact linkmode to advertise and configure for the requested Speed and
Duplex, specially at or over 1G.

Using phy_caps_lookup allows us to build a list of the supported
linkmodes at that speed that we can advertise instead of the first mode
that matches.

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-9-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phy: Use an internal, searchable storage for the linkmodes

2025-03-18T08:03:11+00:00

The canonical definition for all the link modes is in linux/ethtool.h,
which is complemented by the link_mode_params array stored in
net/ethtool/common.h . That array contains all the metadata about each
of these modes, including the Speed and Duplex information.

Phylib and phylink needs that information as well for internal
management of the link, which was done by duplicating that information
in locally-stored arrays and lookup functions. This makes it easy for
developpers adding new modes to forget modifying phylib and phylink
accordingly.

However, the link_mode_params array in net/ethtool/common.c is fairly
inefficient to search through, as it isn't sorted in any manner. Phylib
and phylink perform a lot of lookup operations, mostly to filter modes
by speed and/or duplex.

We therefore introduce the link_caps private array in phy_caps.c, that
indexes linkmodes in a more efficient manner. Each element associated a
tuple  to a bitfield of all the linkmodes runs at these
speed/duplex.

We end-up with an array that's fairly short, easily addressable and that
it optimised for the typical use-cases of phylib/phylink.

That array is initialized at the same time as phylib. As the
link_mode_params array is part of the net stack, which phylink depends
on, it should always be accessible from phylib.

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-3-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phy: move PHY package code from phy_device.c to own source file

2025-03-06T03:13:52+00:00

This patch is the first step in moving the PHY package related code
to its own source file. No functional change intended.

Signed-off-by: Heiner Kallweit 
Link: https://patch.msgid.link/57df5c19-fbcd-45a7-9afd-cd4f74d7fa76@gmail.com
Signed-off-by: Jakub Kicinski

net: phy: add phylib-internal.h

2025-02-25T03:14:31+00:00

This patch is a starting point for moving phylib-internal
declarations to a private header file.

Signed-off-by: Heiner Kallweit 
Link: https://patch.msgid.link/082eacd2-a888-4716-8797-b3491ce02820@gmail.com
Signed-off-by: Jakub Kicinski

net: phy: remove disabled EEE modes from advertising_eee in phy_probe

2025-02-19T02:07:09+00:00

A PHY driver may populate eee_disabled_modes in its probe or get_features
callback, therefore filter the EEE advertisement read from the PHY.

Signed-off-by: Heiner Kallweit 
Reviewed-by: Andrew Lunn 
Reviewed-by: Russell King (Oracle) 
Link: https://patch.msgid.link/493f3e2e-9cfc-445d-adbe-58d9c117a489@gmail.com
Signed-off-by: Jakub Kicinski

net: phy: Add helper for getting tx amplitude gain

2025-02-18T00:40:42+00:00

Add helper which returns the tx amplitude gain defined in device tree.
Modifying it can be necessary to compensate losses on the PCB and
connector, so the voltages measured on the RJ45 pins are conforming.

Signed-off-by: Dimitri Fedrau 
Reviewed-by: Andrew Lunn 
Link: https://patch.msgid.link/20250214-dp83822-tx-swing-v5-2-02ca72620599@liebherr.com
Signed-off-by: Jakub Kicinski