[PATCH RESEND net-next v17 00/10] net: phy_port: SFP modules representation and phy_port listing

Maxime Chevallier posted 10 patches 2 weeks ago
Documentation/netlink/specs/ethtool.yaml      |  55 +++
Documentation/networking/ethtool-netlink.rst  |  34 ++
Documentation/networking/phy-port.rst         |  26 +-
MAINTAINERS                                   |   1 +
drivers/net/phy/phy-caps.h                    |   2 +
drivers/net/phy/phy_caps.c                    |  26 ++
drivers/net/phy/phy_device.c                  | 186 +++++++--
drivers/net/phy/phy_link_topology.c           | 101 ++++-
drivers/net/phy/phylink.c                     | 128 +++++-
include/linux/phy.h                           |  10 +
include/linux/phy_link_topology.h             |  44 ++
include/linux/phy_port.h                      |   5 +
.../uapi/linux/ethtool_netlink_generated.h    |  22 +
net/core/dev.c                                |   1 +
net/ethtool/Makefile                          |   2 +-
net/ethtool/netlink.c                         |  25 ++
net/ethtool/netlink.h                         |   8 +
net/ethtool/port.c                            | 382 ++++++++++++++++++
18 files changed, 1020 insertions(+), 38 deletions(-)
create mode 100644 net/ethtool/port.c
[PATCH RESEND net-next v17 00/10] net: phy_port: SFP modules representation and phy_port listing
Posted by Maxime Chevallier 2 weeks ago
Hello everyone,

Here's V17 (again) for the phy_port improved SFP support and netlink
interface. Resending as some of yesterday's patches didn't feel like
going to the netdev list...

V17 addresses the port_id wrapparound with the xarray insertion, and the
missing comment during the ethtool header regen from the YNL specs.

This work extends on the recent addition of phy_port representation to enable
listing the front-facing ports of an interface. For now, we don't control
these ports, we merely list their presence and their capabilities.

As the most common use-case of multi-port interfaces is combo-ports that
provide both RJ45 and SFP connectors on a single MAC, there's a lot of
SFP stuff in this series.

This series is in 2 main parts. The first one aims at representing the
SFP cages and modules using phy_port, as combo-ports with RJ45 + SFP are
by far the most common cases for multi-connector setups.

The second part is the netlink interface to list those ports, now that
most use-cases are covered.

Let's see what we can do with some examples of the new ethtool API :

- Get MII interfaces supported by an empty SFP cage :

# ethtool --show-ports eth3

Port for eth3:
	Port id: 1
	Supported MII interfaces : sgmii, 1000base-x, 2500base-x
	Port type: sfp

- Get Combo-ports supported modes, on each port :

# ethtool --show-ports eth1

Port for eth1:
	Port id: 1
	Supported link modes:  10baseT/Half 10baseT/Full
	                       100baseT/Half 100baseT/Full
	                       1000baseT/Full
	                       10000baseT/Full
	                       2500baseT/Full
	                       5000baseT/Full

	Port type: mdi

Port for eth1:
	Port id: 2
	Supported MII interfaces : 10gbase-r
	Port type: sfp

- Get Achievable linkmodes on a SFP module (combo port with a DAC in the
SFP cage)

# ethtool --show-ports eth1

Port for eth1:
	Port id: 1
	Supported link modes:  10baseT/Half 10baseT/Full
	                       100baseT/Half 100baseT/Full
	                       1000baseT/Full
	                       10000baseT/Full
	                       2500baseT/Full
	                       5000baseT/Full
	Port type: mdi

Port for eth1:
	Port id: 2
	Supported MII interfaces : 10gbase-r
	Port type: sfp

Port for eth1:
	Port id: 3
	Upstream id: 2
	Supported link modes:  10000baseCR/Full
	Port type: mdi

Note that here, we have 3 ports :
 - The Copper port
 - The SFP Cage itself, marked as 'occupied'
 - The SFP module

This series builds on top of phy_port and phy_link_topology to allow
tracking the ports of an interface. We maintain a list of supported
linkmodes/interfaces on each port, which allows for fine-grained
reporting of each port's capability.

What this series doesn't do :
 - We don't support selecting which port is active. This is the next step.
 - We only support PHY-driven combo ports. The end-goal of this whole
   journey that started with phy_link_topology is to get support for MII
   muxes, such as the one we have on the Turris Omnia. This will eventually
   be upstreamed as well.

If you want to play around with it, here's [1] the patched ethtool that I've
been using to produce the outputs above.

Thanks !

Maxime

[1] : https://github.com/minimaxwell/ethtool/tree/mc/ethtool_port

Changelog :

Changes in v17:
 - Handle port index wraparound
 - Regen the ethtool headers, now with the comment :)

Changes in v16:
https://lore.kernel.org/r/20260902212135.1805948-1-maxime.chevallier@bootlin.com
 - unregister phy_ports at phy_detach
 - typos in patch 1 (of -> or)
 - Fix the netlink specs

Changes in v15:
https://lore.kernel.org/netdev/20260801074332.98755-1-maxime.chevallier@bootlin.com/
 - Fail on port access for ops-locked devices
 - Use a direct phy_port pointer for upstream tracking
 - Addressed the kdoc issues

Changes in v14:
https://lore.kernel.org/netdev/20260720174808.139573-1-maxime.chevallier@bootlin.com/
 - Added a big comment on the first patch for the topo alloc potential
   races
 - Fixed the multi-buff DUMP on last patch with a separate iterator for
   dumps
 - Fixed some typos in the documentation

Changes in V13:
V13: https://lore.kernel.org/r/20260701110427.143945-1-maxime.chevallier@bootlin.com
 - Rebase on net-next
 - Fix the SFP bus cleanup path in patch 5

Changes in V12:
V12: https://lore.kernel.org/r/20260615153907.862987-1-maxime.chevallier@bootlin.com
 - Rebased on net-next, including fixes on the phy probing and cleanup
   paths
 - Rebased on Jakub's netdev_ops_locked changes in phy_link_topology
 - Fixed some typos reported by Andrew and sashiko in the documentation

Changes in v11:
V11:https://lore.kernel.org/r/20260521121040.1199622-1-maxime.chevallier@bootlin.com
 - Aggregated Andrew's reviews :)
 - Removed the "vacant" field, replaced it with "upstream_port"

Changes in V10:
V10: https://lore.kernel.org/r/20260513130521.1064094-1-maxime.chevallier@bootlin.com
 - Rebase on net-next
 - Rename phylink/phy_device sfp_bus_port to sfp_cage_port
 - Sashiko's reviews were mostly unrealistic or wrong :(

Changes in V9:
V9: https://lore.kernel.org/r/20260403123755.175742-1-maxime.chevallier@bootlin.com
 - Added missing netlink doc updates for u8->u32 conversion
 - Removed dead code with a condition that can never be true in
   phylink's mod_port code
 - Fixed the error path in phy_sfp_connect_phy

Changes in v8:
V8: https://lore.kernel.org/r/20260325081937.571115-1-maxime.chevallier@bootlin.com
 - Set the new phydev.has_sfp_mod_phy field when we're sure that no
   errors occured
 - Fix formatting of the copyright info in ethnl port
 - Use a policy to validate the range of port_id
 - Use GENL_REQ_ATTR_CHECK
 - alpha-sort headers
 - use u32 in netlink messages
 - return better error codes
 - don't check the skb len, the core does that

Changes in V7:
V7: https://lore.kernel.org/all/20260309152747.702373-1-maxime.chevallier@bootlin.com/
 - Changed the port cleanup path to use list_for_each_entry_continue_reverse
 - Adjusted the cleanup path in phylink for the port vacant state
 - Pass the right cmd for the netlink dump message

Changes in V6:
V6: https://lore.kernel.org/r/20260304145444.442334-1-maxime.chevallier@bootlin.com
 - Added some comments in th mod_port cleanup
 - changed some kmalloc to kmalloc_obj
 - Removed some phy_link_topo_del_port that wasn't needed

Changes in V5:
V5: https://lore.kernel.org/r/20260205092317.755906-1-maxime.chevallier@bootlin.com
 - Fixed a check on a potentially un-initialized pointer, reported by
   Simon
 - Fixed a documentation formatting issue
 - Remove a stray pr_info
 - Rebased on net-next

Changes in V4:
V4 : https://lore.kernel.org/netdev/20260203172839.548524-1-maxime.chevallier@bootlin.com/
 - Add a cleanup patch for the of port parsing
 - Added a match to sync the port's linkmodes with the PHY's for OF
   ports
 - Added RTNL assert in the port_get topo helper
 - nullify the bus port for phylink support
 - Fix some typos

Changes in V3:
V3: https://lore.kernel.org/netdev/20260201151249.642015-1-maxime.chevallier@bootlin.com/
 - Remove the sfp bus ops for nophy, and use .module_start() as
   suggested by Russell
 - Added missing cleanup for the topology, as per AI review
 - Fixed a few typos as per Romain's review
 - Changed "occupied" to "vacant" as per Romain's review
 - Added missing checks for null ports, per AI review

Changes in V2:
V2: https://lore.kernel.org/netdev/20260128204526.170927-1-maxime.chevallier@bootlin.com/
 - Fix the cleanup path of phy_link_topo_add_phy, as per AI review
 - Fix the cleanup path of phy_sfp_probe, as per AI review
 - Fix the call-site of the disconnect_nophy sfp bus ops, per AI review
 - Fix the netdev-less case uin phylink, per AI review
 - Fix the prototype of phy_link_topo_get_port for the stubs
 - Dropped patch 11. It ended-up breaking 'allnoconfig', so instead we
   built a phy_interface_names array in net/ethtool/netlink.c
 - Fix an ethool-netlink spec discrepancy with the type of an attribute
 - Fix the size computation in the netlink port API
 - Fix the cleanup path in the netlink port API

V1: https://lore.kernel.org/netdev/20260127134202.8208-1-maxime.chevallier@bootlin.com/



Maxime Chevallier (10):
  net: phy: phy_link_topology: Add a helper for opportunistic alloc
  net: phy: phy_link_topology: Track ports in phy_link_topology
  net: phylink: Register a phy_port for MAC-driven SFP cages
  net: phy: Create SFP phy_port before registering upstream
  net: phy: Represent PHY-less SFP modules with phy_port
  net: phy: phy_port: Store information about a port's upstream
  net: phy: phy_link_topology: Add a helper to retrieve ports
  netlink: specs: Add ethernet port listing with ethtool
  net: ethtool: Introduce ethtool command to list ports
  Documentation: networking: Update the phy_port infrastructure
    description

 Documentation/netlink/specs/ethtool.yaml      |  55 +++
 Documentation/networking/ethtool-netlink.rst  |  34 ++
 Documentation/networking/phy-port.rst         |  26 +-
 MAINTAINERS                                   |   1 +
 drivers/net/phy/phy-caps.h                    |   2 +
 drivers/net/phy/phy_caps.c                    |  26 ++
 drivers/net/phy/phy_device.c                  | 186 +++++++--
 drivers/net/phy/phy_link_topology.c           | 101 ++++-
 drivers/net/phy/phylink.c                     | 128 +++++-
 include/linux/phy.h                           |  10 +
 include/linux/phy_link_topology.h             |  44 ++
 include/linux/phy_port.h                      |   5 +
 .../uapi/linux/ethtool_netlink_generated.h    |  22 +
 net/core/dev.c                                |   1 +
 net/ethtool/Makefile                          |   2 +-
 net/ethtool/netlink.c                         |  25 ++
 net/ethtool/netlink.h                         |   8 +
 net/ethtool/port.c                            | 382 ++++++++++++++++++
 18 files changed, 1020 insertions(+), 38 deletions(-)
 create mode 100644 net/ethtool/port.c

-- 
2.55.0
Re: [PATCH RESEND net-next v17 00/10] net: phy_port: SFP modules representation and phy_port listing
Posted by Aleksei Sviridkin 17 hours ago
Hi Maxime,

I ran v17 on a Keenetic KN-1012 (MT7981B + MT7531). Switch port 5
(lan4) goes either to an SFP cage or to an EN8811H copper PHY, and the
bootloader picks one devicetree variant per boot. The series was
backported to OpenWrt's 6.18 kernel together with the phy_port base and
its fixes, with PROVE_LOCKING and DEBUG_ATOMIC_SLEEP enabled.

Copper variant: lan4 lists one mdi port, id 1, with 100/1000/2500baseT,
the same modes the PHY reports. The EN8811H attaches late, after the
netdev is registered, because it waits for its firmware. The port still
shows up, and traffic passes. The other user ports each list one mdi
port.

With a small netlink client I also checked the calls the ethtool CLI
can't make. An unfiltered dump returns the five ports and then DONE.
A dump filtered on a netdev without a topology returns nothing and a
clean DONE. A DO with a valid PORT_ID returns the port. An unknown id
gives ENODEV, id 0 gives ERANGE from the policy, and a request with no
id gives EINVAL. lockdep stayed clean and debug_locks stayed 1.

SFP variant, with the cage port and a module port:

  Port for lan4:
          Port id: 1
          Supported MII interfaces : sgmii, 1000base-x, 2500base-x
          Port type: sfp

  Port for lan4:
          Port id: 3
          Upstream id: 1
          Supported link modes:  2500baseX/Full
                                 1000baseX/Full
          Port type: mdi

That is a passive DAC. A GPON ONU stick gives 1000baseX/Full, and
phylink moves to 1000base-x. On every removal the module port goes away
and the cage port stays. Every insert gets a new id, with no stale or
duplicate entry. I tried a replug within one second, two fast
out/in cycles, and swapping the DAC for the ONU with no pause. The
double cycle didn't manage an insert while the previous probe was still
running, since a hand can't beat the ~0.9s probe. lockdep stayed clean
throughout.

Over the DAC at 1000base-X to a UniFi UDR7 (whose SFP+ path goes
through its CPU), iperf3 gives 926 Mbit/s board to UDR7 and 606 Mbit/s
back, with no interface errors, no link drops and lockdep clean. I also pulled
the DAC while a ping6 flood was running and plugged it back in: the
module port went away, came back with a new id, and the link and
traffic recovered.

Not covered:
- A module with its own PHY (06/10): neither of my modules probed one.
- A dump that spans more than one skb: five ports fit in one.

Three notes:

The ethtool branch linked in the cover still reads PORT_VACANT and a u8
port type, while v17 has UPSTREAM_PORT (u32) in that slot and a u32
type. I adapted it locally. Could you push the ethtool you used for the
cover letter?

The raw supported-modes of a PHY's default port also carry the
Autoneg, TP and MII bits, e.g. "... 1000baseT/Full Autoneg TP MII
2500baseT/Full" on lan4. ethtool hides them, but MII on an mdi port
looks odd to anyone reading the attribute directly. Is that intended?

A module port follows the netdev's admin state rather than module
presence. With lan4 down, a module sitting in the cage isn't listed,
because sfp_module_stop() runs phylink_del_sfp_mod_port(). After ifup
it comes back under a new id, so every ifdown/ifup renumbers it. Is
that intended? From userspace, "port 3 upstream 1" isn't stable across
an ifup.

Tested-by: Aleksei Sviridkin <f@lex.la>

Aleksei