linux.git/drivers/net/phy/phy_caps.c, branch v6.16

net: phy: phy_caps: Don't skip better duplex macth on non-exact match

2025-06-12T15:00:53+00:00

When performing a non-exact phy_caps lookup, we are looking for a
supported mode that matches as closely as possible the passed speed/duplex.

Blamed patch broke that logic by returning a match too early in case
the caller asks for half-duplex, as a full-duplex linkmode may match
first, and returned as a non-exact match without even trying to mach on
half-duplex modes.

Reported-by: Jijie Shao 
Closes: https://lore.kernel.org/netdev/20250603102500.4ec743cf@fedora/T/#m22ed60ca635c67dc7d9cbb47e8995b2beb5c1576
Tested-by: Jijie Shao 
Reviewed-by: Larysa Zaremba 
Fixes: fc81e257d19f ("net: phy: phy_caps: Allow looking-up link caps based on speed and duplex")
Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250606094321.483602-1-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski

net: phylink: Use phy_caps to get an interface's capabilities and modes

2025-03-18T08:03:12+00:00

Phylink has internal code to get the MAC capabilities of a given PHY
interface (what are the supported speed and duplex).

Extract that into phy_caps, but use the link_capa for conversion. Add an
internal phylink helper for the link caps -> mac caps conversion, and
use this in phylink_caps_to_linkmodes().

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-14-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phylink: Convert capabilities to linkmodes using phy_caps

2025-03-18T08:03:12+00:00

phylink_caps_to_linkmodes() is used to derive a list of linkmodes that
can be conceivably exposed using a given set of speeds and duplex
through phylink's MAC capabilities.

This list can be derived from the link_caps array in phy_caps, provided
we convert the MAC capabilities into a LINK_CAPA bitmask first.

Introduce an internal phylink helper phylink_caps_to_link_caps() to
convert from MAC capabilities into phy_caps, then  phy_caps_linkmodes()
to do the link_caps -> linkmodes conversion.

This avoids having to update phylink for every new linkmode.

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-13-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phy: phy_caps: Allow looking-up link caps based on speed and duplex

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

As the link_caps array is efficient for  lookups,
implement a function for speed/duplex lookups that matches a given
mask. This replicates to some extent the phy_lookup_settings()
behaviour, matching full link_capabilities instead of a single linkmode.

phy.c's phy_santize_settings() and phylink's
phylink_ethtool_ksettings_set() performs such lookup using the
phy_settings table, but are only interested in the actual speed/duplex
that were matched, rathet than the individual linkmode.

Similar to phy_lookup_settings(), the newly introduced phy_caps_lookup()
will run through the link_caps[] array by descending speed/duplex order.

If the link_capabilities for a given  tuple intersects the
passed linkmodes, we consider that a match.

Similar to phy_lookup_settings(), we also allow passing an 'exact'
boolean, allowing non-exact match. Here, we MUST always match the
linkmodes mask, but we allow matching on lower speed settings.

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-8-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phy: phy_caps: Implement link_capabilities lookup by linkmode

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

In several occasions, phylib needs to lookup a set of matching speed and
duplex against a given linkmode set. Instead of relying on the
phy_settings array and thus iterate over the whole linkmodes list, use
the link_capabilities array to lookup these matches, as we aren't
interested in the actual link setting that matches but rather the speed
and duplex for that setting.

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-7-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phy: phy_caps: Introduce phy_caps_valid

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

With the link_capabilities array, it's trivial to validate a given mask
againts a  tuple. Create a helper for that purpose, and
use it to replace a phy_settings lookup in phy_check_valid();

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-6-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phy: phy_caps: Move __set_linkmode_max_speed to phy_caps

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

Convert the __set_linkmode_max_speed to use the link_capabilities array.
This makes it easy to clamp the linkmodes to a given max speed.
Introduce a new helper phy_caps_linkmode_max_speed to replace the
previous one that used phy_settings.

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-5-maxime.chevallier@bootlin.com
Signed-off-by: Paolo Abeni

net: phy: phy_caps: Move phy_speeds to phy_caps

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

Use the newly introduced link_capabilities array to derive the list of
possible speeds when given a combination of linkmodes. As
link_capabilities is indexed by speed, we don't have to iterate the
whole phy_settings array.

Signed-off-by: Maxime Chevallier 
Link: https://patch.msgid.link/20250307173611.129125-4-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