Introduce PHY listing and link_topology tracking

Hello everyone,

This is V15 of the phy_link_topology series, aiming at improving support
for multiple PHYs being attached to the same MAC.

The main change in V15 is the introduction of patch 12, that drops a
non-needed check on the genl_info parameter passed on the ethnl
ops for strset. This extra check shouldn't be needed as the genl_info
shouldn't be NULL, but it tricks smatch into thinking it can, thus
generating some warnings in patch 13. Thanks Simon and Dan for the
report.

All other patches are left unchanged from V14, besides a net-next
rebase.

As a remainder, here's what the PHY listings would look like :
 - eth0 has a 88x3310 acting as media converter, and an SFP module with
   an embedded 88e1111 PHY
 - eth2 has a 88e1510 PHY

# ethtool --show-phys *

PHY for eth0:
PHY index: 1
Driver name: mv88x3310
PHY device name: f212a600.mdio-mii:00
Downstream SFP bus name: sfp-eth0
PHY id: 0
Upstream type: MAC

PHY for eth0:
PHY index: 2
Driver name: Marvell 88E1111
PHY device name: i2c:sfp-eth0:16
PHY id: 21040322
Upstream type: PHY
Upstream PHY index: 1
Upstream SFP name: sfp-eth0

PHY for eth2:
PHY index: 1
Driver name: Marvell 88E1510
PHY device name: f212a200.mdio-mii:00
PHY id: 21040593
Upstream type: MAC

Ethtool patches : https://github.com/minimaxwell/ethtool/tree/mc/topo-v14

Link to V14: https://lore.kernel.org/netdev/20240701131801.1227740-1-m...
Link to V13: https://lore.kernel.org/netdev/20240607071836.911403-1-ma...
Link to v12: https://lore.kernel.org/netdev/20240605124920.720690-1-ma...
Link to v11: https://lore.kernel.org/netdev/20240404093004.2552221-1-m...
Link to V10: https://lore.kernel.org/netdev/20240304151011.1610175-1-m...
Link to V9: https://lore.kernel.org/netdev/20240228114728.51861-1-max...
Link to V8: https://lore.kernel.org/netdev/20240220184217.3689988-1-m...
Link to V7: https://lore.kernel.org/netdev/20240213150431.1796171-1-m...
Link to V6: https://lore.kernel.org/netdev/20240126183851.2081418-1-m...
Link to V5: https://lore.kernel.org/netdev/20231221180047.1924733-1-m...
Link to V4: https://lore.kernel.org/netdev/20231215171237.1152563-1-m...
Link to V3: https://lore.kernel.org/netdev/20231201163704.1306431-1-m...
Link to V2: https://lore.kernel.org/netdev/20231117162323.626979-1-ma...
Link to V1: https://lore.kernel.org/netdev/20230907092407.647139-1-ma...

More discussions on specific issues that happened in 6.9-rc:

https://lore.kernel.org/netdev/20240412104615.3779632-1-m...
https://lore.kernel.org/netdev/20240429131008.439231-1-ma...
https://lore.kernel.org/netdev/20240507102822.2023826-1-m...


Maxime Chevallier (14):
  net: phy: Introduce ethernet link topology representation
  net: sfp: pass the phy_device when disconnecting an sfp module's PHY
  net: phy: add helpers to handle sfp phy connect/disconnect
  net: sfp: Add helper to return the SFP bus name
  net: ethtool: Allow passing a phy index for some commands
  netlink: specs: add phy-index as a header parameter
  net: ethtool: Introduce a command to list PHYs on an interface
  netlink: specs: add ethnl PHY_GET command set
  net: ethtool: plca: Target the command to the requested PHY
  net: ethtool: pse-pd: Target the command to the requested PHY
  net: ethtool: cable-test: Target the command to the requested PHY
  net: ethtool: strset: Remove unnecessary check on genl_info
  net: ethtool: strset: Allow querying phy stats by index
  Documentation: networking: document phy_link_topology

 Documentation/netlink/specs/ethtool.yaml      |  62 ++++
 Documentation/networking/ethtool-netlink.rst  |  52 +++
 Documentation/networking/index.rst            |   1 +
 .../networking/phy-link-topology.rst          | 121 +++++++
 MAINTAINERS                                   |   1 +
 drivers/net/phy/Makefile                      |   2 +-
 drivers/net/phy/marvell-88x2222.c             |   2 +
 drivers/net/phy/marvell.c                     |   2 +
 drivers/net/phy/marvell10g.c                  |   2 +
 drivers/net/phy/phy_device.c                  |  48 +++
 drivers/net/phy/phy_link_topology.c           | 105 ++++++
 drivers/net/phy/phylink.c                     |   3 +-
 drivers/net/phy/qcom/at803x.c                 |   2 +
 drivers/net/phy/qcom/qca807x.c                |   2 +
 drivers/net/phy/sfp-bus.c                     |  15 +-
 include/linux/netdevice.h                     |   4 +-
 include/linux/phy.h                           |   6 +
 include/linux/phy_link_topology.h             |  82 +++++
 include/linux/sfp.h                           |   8 +-
 include/uapi/linux/ethtool.h                  |  16 +
 include/uapi/linux/ethtool_netlink.h          |  21 ++
 net/core/dev.c                                |  15 +
 net/ethtool/Makefile                          |   3 +-
 net/ethtool/cabletest.c                       |  35 +-
 net/ethtool/netlink.c                         |  66 +++-
 net/ethtool/netlink.h                         |  33 ++
 net/ethtool/phy.c                             | 312 ++++++++++++++++++
 net/ethtool/plca.c                            |  30 +-
 net/ethtool/pse-pd.c                          |  30 +-
 net/ethtool/strset.c                          |  27 +-
 30 files changed, 1056 insertions(+), 52 deletions(-)
 create mode 100644 Documentation/networking/phy-link-topology.rst
 create mode 100644 drivers/net/phy/phy_link_topology.c
 create mode 100644 include/linux/phy_link_topology.h
 create mode 100644 net/ethtool/phy.c

-- 
2.45.1