linux-stable.git/drivers/net/phy/phylink.c, branch linux-rolling-lts Linux kernel stable tree net: phylink: add missing supported link modes for the fixed-link 2025-11-19T16:31:11+00:00 Wei Fang wei.fang@nxp.com 2025-11-17T10:29:43+00:00 e31a11be41cd134f245c01d1329e7bc89aba78fb Pause, Asym_Pause and Autoneg bits are not set when pl->supported is initialized, so these link modes will not work for the fixed-link. This leads to a TCP performance degradation issue observed on the i.MX943 platform. The switch CPU port of i.MX943 is connected to an ENETC MAC, this link is a fixed link and the link speed is 2.5Gbps. And one of the switch user ports is the RGMII interface, and its link speed is 1Gbps. If the flow-control of the fixed link is not enabled, we can easily observe the iperf performance of TCP packets is very low. Because the inbound rate on the CPU port is greater than the outbound rate on the user port, the switch is prone to congestion, leading to the loss of some TCP packets and requiring multiple retransmissions. Solving this problem should be as simple as setting the Asym_Pause and Pause bits. The reason why the Autoneg bit needs to be set, Russell has gave a very good explanation in the thread [1], see below. "As the advertising and lp_advertising bitmasks have to be non-empty, and the swphy reports aneg capable, aneg complete, and AN enabled, then for consistency with that state, Autoneg should be set. This is how it was prior to the blamed commit." Fixes: de7d3f87be3c ("net: phylink: Use phy_caps_lookup for fixed-link configuration") Link: https://lore.kernel.org/aRjqLN8eQDIQfBjS@shell.armlinux.org.uk # [1] Signed-off-by: Wei Fang <wei.fang@nxp.com> Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com> Link: https://patch.msgid.link/20251117102943.1862680-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Pause, Asym_Pause and Autoneg bits are not set when pl->supported is
initialized, so these link modes will not work for the fixed-link. This
leads to a TCP performance degradation issue observed on the i.MX943
platform.

The switch CPU port of i.MX943 is connected to an ENETC MAC, this link
is a fixed link and the link speed is 2.5Gbps. And one of the switch
user ports is the RGMII interface, and its link speed is 1Gbps. If the
flow-control of the fixed link is not enabled, we can easily observe
the iperf performance of TCP packets is very low. Because the inbound
rate on the CPU port is greater than the outbound rate on the user port,
the switch is prone to congestion, leading to the loss of some TCP
packets and requiring multiple retransmissions.

Solving this problem should be as simple as setting the Asym_Pause and
Pause bits. The reason why the Autoneg bit needs to be set, Russell
has gave a very good explanation in the thread [1], see below.

"As the advertising and lp_advertising bitmasks have to be non-empty,
and the swphy reports aneg capable, aneg complete, and AN enabled, then
for consistency with that state, Autoneg should be set. This is how it
was prior to the blamed commit."

Fixes: de7d3f87be3c ("net: phylink: Use phy_caps_lookup for fixed-link configuration")
Link: https://lore.kernel.org/aRjqLN8eQDIQfBjS@shell.armlinux.org.uk # [1]
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20251117102943.1862680-1-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phylink: use sfp_get_module_caps() 2025-09-22T23:05:15+00:00 Russell King (Oracle) rmk+kernel@armlinux.org.uk 2025-09-16T21:46:57+00:00 cab1165195406a0a28153d61bd14967d8efb67f7 Use sfp_get_module_caps() to get SFP module's capabilities. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/E1uydVp-000000061WW-08YM@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Use sfp_get_module_caps() to get SFP module's capabilities.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1uydVp-000000061WW-08YM@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phylink: warn if deprecated array-style fixed-link binding is used 2025-09-16T01:15:41+00:00 Heiner Kallweit hkallweit1@gmail.com 2025-09-12T19:07:16+00:00 4689a42904299d054e59fc9d59e8e00884ffcf87 The array-style fixed-link binding has been marked deprecated for more than 10 yrs, but still there's a number of users. Print a warning when usage of the deprecated binding is detected. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://patch.msgid.link/cc823d38-2a2c-4c83-9a27-d7f25d61a2de@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The array-style fixed-link binding has been marked deprecated for more
than 10 yrs, but still there's a number of users. Print a warning when
usage of the deprecated binding is detected.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/cc823d38-2a2c-4c83-9a27-d7f25d61a2de@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phy: transfer phy_config_inband() locking responsibility to phylink 2025-09-06T00:49:43+00:00 Vladimir Oltean vladimir.oltean@nxp.com 2025-09-04T12:52:38+00:00 e2a10daba84968f6b5777d150985fd7d6abc9c84 Problem description =================== Lockdep reports a possible circular locking dependency (AB/BA) between &pl->state_mutex and &phy->lock, as follows. phylink_resolve() // acquires &pl->state_mutex -> phylink_major_config() -> phy_config_inband() // acquires &pl->phydev->lock whereas all the other call sites where &pl->state_mutex and &pl->phydev->lock have the locking scheme reversed. Everywhere else, &pl->phydev->lock is acquired at the top level, and &pl->state_mutex at the lower level. A clear example is phylink_bringup_phy(). The outlier is the newly introduced phy_config_inband() and the existing lock order is the correct one. To understand why it cannot be the other way around, it is sufficient to consider phylink_phy_change(), phylink's callback from the PHY device's phy->phy_link_change() virtual method, invoked by the PHY state machine. phy_link_up() and phy_link_down(), the (indirect) callers of phylink_phy_change(), are called with &phydev->lock acquired. Then phylink_phy_change() acquires its own &pl->state_mutex, to serialize changes made to its pl->phy_state and pl->link_config. So all other instances of &pl->state_mutex and &phydev->lock must be consistent with this order. Problem impact ============== I think the kernel runs a serious deadlock risk if an existing phylink_resolve() thread, which results in a phy_config_inband() call, is concurrent with a phy_link_up() or phy_link_down() call, which will deadlock on &pl->state_mutex in phylink_phy_change(). Practically speaking, the impact may be limited by the slow speed of the medium auto-negotiation protocol, which makes it unlikely for the current state to still be unresolved when a new one is detected, but I think the problem is there. Nonetheless, the problem was discovered using lockdep. Proposed solution ================= Practically speaking, the phy_config_inband() requirement of having phydev->lock acquired must transfer to the caller (phylink is the only caller). There, it must bubble up until immediately before &pl->state_mutex is acquired, for the cases where that takes place. Solution details, considerations, notes ======================================= This is the phy_config_inband() call graph: sfp_upstream_ops :: connect_phy() | v phylink_sfp_connect_phy() | v phylink_sfp_config_phy() | | sfp_upstream_ops :: module_insert() | | | v | phylink_sfp_module_insert() | | | | sfp_upstream_ops :: module_start() | | | | | v | | phylink_sfp_module_start() | | | | v v | phylink_sfp_config_optical() phylink_start() | | | phylink_resume() v v | | phylink_sfp_set_config() | | | v v v phylink_mac_initial_config() | phylink_resolve() | | phylink_ethtool_ksettings_set() v v v phylink_major_config() | v phy_config_inband() phylink_major_config() caller #1, phylink_mac_initial_config(), does not acquire &pl->state_mutex nor do its callers. It must acquire &pl->phydev->lock prior to calling phylink_major_config(). phylink_major_config() caller #2, phylink_resolve() acquires &pl->state_mutex, thus also needs to acquire &pl->phydev->lock. phylink_major_config() caller #3, phylink_ethtool_ksettings_set(), is completely uninteresting, because it only calls phylink_major_config() if pl->phydev is NULL (otherwise it calls phy_ethtool_ksettings_set()). We need to change nothing there. Other solutions =============== The lock inversion between &pl->state_mutex and &pl->phydev->lock has occurred at least once before, as seen in commit c718af2d00a3 ("net: phylink: fix ethtool -A with attached PHYs"). The solution there was to simply not call phy_set_asym_pause() under the &pl->state_mutex. That cannot be extended to our case though, where the phy_config_inband() call is much deeper inside the &pl->state_mutex section. Fixes: 5fd0f1a02e75 ("net: phylink: add negotiation of in-band capabilities") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/20250904125238.193990-2-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Problem description
===================

Lockdep reports a possible circular locking dependency (AB/BA) between
&pl->state_mutex and &phy->lock, as follows.

phylink_resolve() // acquires &pl->state_mutex
-> phylink_major_config()
   -> phy_config_inband() // acquires &pl->phydev->lock

whereas all the other call sites where &pl->state_mutex and
&pl->phydev->lock have the locking scheme reversed. Everywhere else,
&pl->phydev->lock is acquired at the top level, and &pl->state_mutex at
the lower level. A clear example is phylink_bringup_phy().

The outlier is the newly introduced phy_config_inband() and the existing
lock order is the correct one. To understand why it cannot be the other
way around, it is sufficient to consider phylink_phy_change(), phylink's
callback from the PHY device's phy->phy_link_change() virtual method,
invoked by the PHY state machine.

phy_link_up() and phy_link_down(), the (indirect) callers of
phylink_phy_change(), are called with &phydev->lock acquired.
Then phylink_phy_change() acquires its own &pl->state_mutex, to
serialize changes made to its pl->phy_state and pl->link_config.
So all other instances of &pl->state_mutex and &phydev->lock must be
consistent with this order.

Problem impact
==============

I think the kernel runs a serious deadlock risk if an existing
phylink_resolve() thread, which results in a phy_config_inband() call,
is concurrent with a phy_link_up() or phy_link_down() call, which will
deadlock on &pl->state_mutex in phylink_phy_change(). Practically
speaking, the impact may be limited by the slow speed of the medium
auto-negotiation protocol, which makes it unlikely for the current state
to still be unresolved when a new one is detected, but I think the
problem is there. Nonetheless, the problem was discovered using lockdep.

Proposed solution
=================

Practically speaking, the phy_config_inband() requirement of having
phydev->lock acquired must transfer to the caller (phylink is the only
caller). There, it must bubble up until immediately before
&pl->state_mutex is acquired, for the cases where that takes place.

Solution details, considerations, notes
=======================================

This is the phy_config_inband() call graph:

                          sfp_upstream_ops :: connect_phy()
                          |
                          v
                          phylink_sfp_connect_phy()
                          |
                          v
                          phylink_sfp_config_phy()
                          |
                          |   sfp_upstream_ops :: module_insert()
                          |   |
                          |   v
                          |   phylink_sfp_module_insert()
                          |   |
                          |   |   sfp_upstream_ops :: module_start()
                          |   |   |
                          |   |   v
                          |   |   phylink_sfp_module_start()
                          |   |   |
                          |   v   v
                          |   phylink_sfp_config_optical()
 phylink_start()          |   |
   |   phylink_resume()   v   v
   |   |  phylink_sfp_set_config()
   |   |  |
   v   v  v
 phylink_mac_initial_config()
   |   phylink_resolve()
   |   |  phylink_ethtool_ksettings_set()
   v   v  v
   phylink_major_config()
            |
            v
    phy_config_inband()

phylink_major_config() caller #1, phylink_mac_initial_config(), does not
acquire &pl->state_mutex nor do its callers. It must acquire
&pl->phydev->lock prior to calling phylink_major_config().

phylink_major_config() caller #2, phylink_resolve() acquires
&pl->state_mutex, thus also needs to acquire &pl->phydev->lock.

phylink_major_config() caller #3, phylink_ethtool_ksettings_set(), is
completely uninteresting, because it only calls phylink_major_config()
if pl->phydev is NULL (otherwise it calls phy_ethtool_ksettings_set()).
We need to change nothing there.

Other solutions
===============

The lock inversion between &pl->state_mutex and &pl->phydev->lock has
occurred at least once before, as seen in commit c718af2d00a3 ("net:
phylink: fix ethtool -A with attached PHYs"). The solution there was to
simply not call phy_set_asym_pause() under the &pl->state_mutex. That
cannot be extended to our case though, where the phy_config_inband()
call is much deeper inside the &pl->state_mutex section.

Fixes: 5fd0f1a02e75 ("net: phylink: add negotiation of in-band capabilities")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/20250904125238.193990-2-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phylink: add lock for serializing concurrent pl->phydev writes with resolver 2025-09-06T00:49:43+00:00 Vladimir Oltean vladimir.oltean@nxp.com 2025-09-04T12:52:37+00:00 0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3 Currently phylink_resolve() protects itself against concurrent phylink_bringup_phy() or phylink_disconnect_phy() calls which modify pl->phydev by relying on pl->state_mutex. The problem is that in phylink_resolve(), pl->state_mutex is in a lock inversion state with pl->phydev->lock. So pl->phydev->lock needs to be acquired prior to pl->state_mutex. But that requires dereferencing pl->phydev in the first place, and without pl->state_mutex, that is racy. Hence the reason for the extra lock. Currently it is redundant, but it will serve a functional purpose once mutex_lock(&phy->lock) will be moved outside of the mutex_lock(&pl->state_mutex) section. Another alternative considered would have been to let phylink_resolve() acquire the rtnl_mutex, which is also held when phylink_bringup_phy() and phylink_disconnect_phy() are called. But since phylink_disconnect_phy() runs under rtnl_lock(), it would deadlock with phylink_resolve() when calling flush_work(&pl->resolve). Additionally, it would have been undesirable because it would have unnecessarily blocked many other call paths as well in the entire kernel, so the smaller-scoped lock was preferred. Link: https://lore.kernel.org/netdev/aLb6puGVzR29GpPx@shell.armlinux.org.uk/ Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/20250904125238.193990-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Currently phylink_resolve() protects itself against concurrent
phylink_bringup_phy() or phylink_disconnect_phy() calls which modify
pl->phydev by relying on pl->state_mutex.

The problem is that in phylink_resolve(), pl->state_mutex is in a lock
inversion state with pl->phydev->lock. So pl->phydev->lock needs to be
acquired prior to pl->state_mutex. But that requires dereferencing
pl->phydev in the first place, and without pl->state_mutex, that is
racy.

Hence the reason for the extra lock. Currently it is redundant, but it
will serve a functional purpose once mutex_lock(&phy->lock) will be
moved outside of the mutex_lock(&pl->state_mutex) section.

Another alternative considered would have been to let phylink_resolve()
acquire the rtnl_mutex, which is also held when phylink_bringup_phy()
and phylink_disconnect_phy() are called. But since phylink_disconnect_phy()
runs under rtnl_lock(), it would deadlock with phylink_resolve() when
calling flush_work(&pl->resolve). Additionally, it would have been
undesirable because it would have unnecessarily blocked many other call
paths as well in the entire kernel, so the smaller-scoped lock was
preferred.

Link: https://lore.kernel.org/netdev/aLb6puGVzR29GpPx@shell.armlinux.org.uk/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/20250904125238.193990-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phylink: move PHY interrupt request to non-fail path 2025-09-03T23:37:42+00:00 Russell King (Oracle) rmk+kernel@armlinux.org.uk 2025-09-01T11:52:56+00:00 3bc32fd9db47a20f38b0783364fdb2f2f1c97220 The blamed commit added code which could return an error after we requested the PHY interrupt. When we return an error, the caller will call phy_detach() which fails to free the interrupt. Rearrange the code such that failing operations happen before the interrupt is requested, thereby allowing phy_detach() to be used. Note that replacing phy_detach() with phy_disconnect() in these paths could lead to freeing an interrupt which was never requested. Fixes: 1942b1c6f687 ("net: phylink: make configuring clock-stop dependent on MAC support") Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://patch.msgid.link/E1ut35k-00000001UEl-0iq6@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The blamed commit added code which could return an error after we
requested the PHY interrupt. When we return an error, the caller
will call phy_detach() which fails to free the interrupt.

Rearrange the code such that failing operations happen before the
interrupt is requested, thereby allowing phy_detach() to be used.

Note that replacing phy_detach() with phy_disconnect() in these
paths could lead to freeing an interrupt which was never requested.

Fixes: 1942b1c6f687 ("net: phylink: make configuring clock-stop dependent on MAC support")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/E1ut35k-00000001UEl-0iq6@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phylink: disable autoneg for interfaces that have no inband 2025-09-02T23:23:14+00:00 Russell King (Oracle) rmk+kernel@armlinux.org.uk 2025-08-31T17:34:43+00:00 a21202743f9ce4063e86b99cccaef48ef9813379 Mathew reports that as a result of commit 6561f0e547be ("net: pcs: pcs-lynx: implement pcs_inband_caps() method"), 10G SFP modules no longer work with the Lynx PCS. This problem is not specific to the Lynx PCS, but is caused by commit df874f9e52c3 ("net: phylink: add pcs_inband_caps() method") which added validation of the autoneg state to the optical SFP configuration path. Fix this by handling interface modes that fundamentally have no inband negotiation more correctly - if we only have a single interface mode, clear the Autoneg support bit and the advertising mask. If the module can operate with several different interface modes, autoneg may be supported for other modes, so leave the support mask alone and just clear the Autoneg bit in the advertising mask. This restores 10G optical module functionality with PCS that supply their inband support, and makes ethtool output look sane. Reported-by: Mathew McBride <matt@traverse.com.au> Closes: https://lore.kernel.org/r/025c0ebe-5537-4fa3-b05a-8b835e5ad317@app.fastmail.com Fixes: df874f9e52c3 ("net: phylink: add pcs_inband_caps() method") Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> Link: https://patch.msgid.link/E1uslwx-00000001SPB-2kiM@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Mathew reports that as a result of commit 6561f0e547be ("net: pcs:
pcs-lynx: implement pcs_inband_caps() method"), 10G SFP modules no
longer work with the Lynx PCS.

This problem is not specific to the Lynx PCS, but is caused by commit
df874f9e52c3 ("net: phylink: add pcs_inband_caps() method") which added
validation of the autoneg state to the optical SFP configuration path.

Fix this by handling interface modes that fundamentally have no
inband negotiation more correctly - if we only have a single interface
mode, clear the Autoneg support bit and the advertising mask. If the
module can operate with several different interface modes, autoneg may
be supported for other modes, so leave the support mask alone and just
clear the Autoneg bit in the advertising mask.

This restores 10G optical module functionality with PCS that supply
their inband support, and makes ethtool output look sane.

Reported-by: Mathew McBride <matt@traverse.com.au>
Closes: https://lore.kernel.org/r/025c0ebe-5537-4fa3-b05a-8b835e5ad317@app.fastmail.com
Fixes: df874f9e52c3 ("net: phylink: add pcs_inband_caps() method")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/E1uslwx-00000001SPB-2kiM@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phylink: provide phylink_get_inband_type() 2025-09-02T23:23:14+00:00 Russell King (Oracle) rmk+kernel@armlinux.org.uk 2025-08-31T17:34:38+00:00 1bd905dfea9897eafef532000702e63a66849f54 Provide a function to get the type of the inband signalling used for a PHY interface type. This will be used in the subsequent patch to address problems with 10G optical modules. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://patch.msgid.link/E1uslws-00000001SP5-1R2R@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Provide a function to get the type of the inband signalling used for
a PHY interface type. This will be used in the subsequent patch to
address problems with 10G optical modules.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/E1uslws-00000001SP5-1R2R@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phy: MII-Lite PHY interface mode 2025-07-10T02:32:30+00:00 Kamil Horák - 2N kamilh@axis.com 2025-07-08T09:01:37+00:00 67c0170566b55b1f6ee3567c94ff679104277e2d Some Broadcom PHYs are capable to operate in simplified MII mode, without TXER, RXER, CRS and COL signals as defined for the MII. The MII-Lite mode can be used on most Ethernet controllers with full MII interface by just leaving the input signals (RXER, CRS, COL) inactive. The absence of COL signal makes half-duplex link modes impossible but does not interfere with BroadR-Reach link modes on Broadcom PHYs, because they are all full-duplex only. Add MII-Lite interface mode, especially for Broadcom two-wire PHYs. Signed-off-by: Kamil Horák - 2N <kamilh@axis.com> Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/20250708090140.61355-2-kamilh@axis.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Some Broadcom PHYs are capable to operate in simplified MII mode,
without TXER, RXER, CRS and COL signals as defined for the MII.
The MII-Lite mode can be used on most Ethernet controllers with full
MII interface by just leaving the input signals (RXER, CRS, COL)
inactive. The absence of COL signal makes half-duplex link modes
impossible but does not interfere with BroadR-Reach link modes on
Broadcom PHYs, because they are all full-duplex only.

Add MII-Lite interface mode, especially for Broadcom two-wire PHYs.

Signed-off-by: Kamil Horák - 2N <kamilh@axis.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/20250708090140.61355-2-kamilh@axis.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: phylink: add phylink_sfp_select_interface_speed() 2025-07-08T02:02:36+00:00 Russell King (Oracle) rmk+kernel@armlinux.org.uk 2025-07-02T09:44:34+00:00 320164a6e172137bcefea669f0ff6ee3f4c8611e Add phylink_sfp_select_interface_speed() which attempts to select the SFP interface based on the ethtool speed when autoneg is turned off. This allows users to turn off autoneg for SFPs that support multiple interface modes, and have an appropriate interface mode selected. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com> Link: https://patch.msgid.link/E1uWu14-005KXo-IO@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Add phylink_sfp_select_interface_speed() which attempts to select the
SFP interface based on the ethtool speed when autoneg is turned off.
This allows users to turn off autoneg for SFPs that support multiple
interface modes, and have an appropriate interface mode selected.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/E1uWu14-005KXo-IO@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>