[PATCH v7 net-next 0/8] dpll/ice: Add generic DPLL type and full TX reference clock control for E825

[Grzegorz Nitka <grzegorz.nitka@intel.com>]

NOTE: This series is intentionally submitted on net-next (not
intel-wired-lan) as early feedback of DPLL subsystem changes is
welcomed. In the past possible approaches were discussed in [1].

This series adds TX reference clock support for E825 devices and exposes
TX clock selection and synchronization status via the Linux DPLL
subsystem.

Here is the high-level connection diagram for E825 device:
  +------------------------------------------------------------------+
  |                                                                  |
  |                           +-----------------------------+        |
  |                           |                             |        |
  |                           |         MAC                 |        |
  |                           |+------------+-----+         |        |
  |                           ||RX/1588 |PHC|tspll<----\    |        |
+---+----+                    ||MUX     +---+-^---|    |    |        |
| E | RX >--------------------->              |   >--\ |    |        |
| T |    |    /---------------->              |   >-\| |    |        |
| H |----+    |               |+---------+----^---+ || |    |        |
| 1 | TX <----|----------------+TX MUX   < OCXO   | || |    |        |
|   |PLL |    |               ||         |--------| || |    |        |
+---+----+    |           /----+         <-ext_ref<-||-|----|------ext_ref
| E | RX >----/           |   ||         |--------+ || |    |        |
| T |    |                |   ||         <  SyncE | || |    |        |
| H |----+                |   |+-----------^------+ || |    |        |
| 2 | TX <----------------/   |            | /------||-/    |        |
|   |PLL |                    +------------|-|------||------+        |
+---+----+                              /--/ |      ||               |
| . | RX >---                           |    |      ||               |
| . |    |                   +----------|----|------||--+            |
| . |----+                   |        +-^-+--^+     ||  |            |
|   | TX <---                |        |EEC|PPS|     ||  |            |
|   |PLL |                   |        +-------+     ||  |            |
+---+----+                   |        |       <-CLK0/|  |            |
| E | RX >---                |        |  DPLL |      |  |            |
| T |    |                   |        |       <-CLK1-/  |            |
| H |----+                   |        |       |         |            |
| X | TX <---                |        |       <---SMA---<            |
|   |PLL |                   |        |       |         |            |
+---+----+                   |        |       <---GPS---<            |
  |                          |        |       |         |            |
  |                          |        |       <---...---<            |
  |                          |        |       |         |            |
  |                          |        +-------+         |            |
  |                          | External timing module   |            |
  |                          +--------------------------+            |
  +------------------------------------------------------------------+

E825 hardware contains a dedicated TX clock domain with per-port source
selection behavior that is distinct from PPS handling and from board-level
EEC distribution. TX reference clock selection is device-wide, shared
across ports, and mediated by firmware as part of link bring-up. As a
result, TX clock selection intent may differ from effective hardware
configuration, and software must verify outcome after link-up.

To support this, the series extends the DPLL core and the ice driver
incrementally. The series also introduces DPLL_TYPE_GENERIC as a broad
UAPI class for DPLL instances outside PPS/EEC categories. The intent is
to keep type naming reusable and scalable across different ASIC
topologies while preserving functional discoverability via
driver/device context and pin topology.

This follows netdev discussion guidance that UAPI type naming should avoid
location-specific or vendor-specific taxonomy, because such labels do not
scale across different ASIC designs. The function of a given DPLL instance
is already discoverable from driver/device context and pin topology, and
does not require an additional narrow type identifier in UAPI.

At the same time, a separate DPLL object is still needed for E825 TX clock
control/reporting semantics. Using DPLL_TYPE_GENERIC provides a reusable
class for devices outside PPS/EEC without overfitting UAPI naming to one
topology.

The relevant discussion is in [2].

Series content
- add a new generic DPLL type for devices outside PPS/EEC classes;
- relax DPLL pin registration rules for firmware-described shared pins
  and extend pin notifications with a source identifier;
- allow dynamic state control of SyncE reference pins where hardware
  supports it;
- add CPI infrastructure for PHY-side TX clock control on E825C;
- introduce a TX-clock DPLL device and TX reference clock pins
  (EXT_EREF0 and SYNCE) in the ice driver;
- extend the Restart Auto-Negotiation command to carry a TX reference
  clock index;
- implement hardware-backed TX reference clock switching, post-link
  verification, and TX synchronization reporting.

TXCLK pins report TX reference topology only. Actual synchronization
success is reported via DPLL lock status, updated after hardware
verification: external TX references report LOCKED, while the internal
ENET/TXCO source reports UNLOCKED.

This provides reliable TX reference selection and observability on E825
devices using standard DPLL interfaces, without conflating user intent
with effective hardware behavior.

[1] https://lore.kernel.org/netdev/20250905160333.715c34ac@kernel.org/
[2] https://lore.kernel.org/netdev/20260402230626.3826719-1-grzegorz.nitka@intel.com/

Changes in v7:
- rebased
- replace TXC-specific DPLL type with DPLL_TYPE_GENERIC (patch 1/8)
- update TXC framework to use DPLL_TYPE_GENERIC instead of DPLL_TYPE_GENERIC
  (patch 5/8)
- AI-review: added short trailing comment to the local mutex declaration
  to satisfy checkpatch report (patch 6/8)

Changes in v6:
 - rebased
 - AI-review: fix unprotected concurrent access to shared clock
   bitmap (patch 8/8)
 - AI-review: fix potential issue in tx-clk pin state request handling
   ('already set' early-exit based now on tx_clk_req comparison, patch 8/8)
 - AI-review: CPI transaction serialization (patch 6/8) 

Changes in v5:
 - rebased
 - reworded cover letter
 - replace 'ntfy_src' new argument name with 'src_clk_id' and use it
   consistently in DPLL notification calls (patch 3/8)
 - reworded commit message (patch 5/8)
 - use FIELD_PREP/GENMSK macros instead of struct bitfields (patch 6/8)
 - reworded commit message (patch 5/8, patch 8/8)
 - refactor the code to avoid sleeping while DPLL mutex is held (using
   work_queue, patch 8/8)
 - added TXCLK pins and TXC DPLL notifications (patch 8/8)
 - removed 'unused clock disable' mechanism from the scope of this series

Changes in v4:
 - rebased
 - edited, shortened the commit message in 3/8 patch
 - moved ice_get_ctrl_pf to the header file (patch 8/8) and
   removed duplicated static definitions from ice_ptp and ice_txlck
   modules
 - add NULL/invalid pointer checker for returned pointer from
   ice_get_ctrl_pf (patch 8/8)
 - edited error message in case AN restart failure (patch 8/8)

Changes in v3:
- improved commit message (patch 1/8, AI review comment)
- improved deinitialization path in ice_dpll_deinit_txclk_pins to
  avoid potential NULL dereference. NULL checking moved to
  ice_dpll_unregister_pins (patch 5/8, found by AI review)
- removed redundant semicolon (patch 6/8)

Changes in v2:
- rebased
- added autogenerated DPLL files (patch 1/8)
- fixed checkpatch 'parenthesis alignment' warning (patch 2/8)
- fixed error path in ice_dpll_init_txclk_pins (AI warning, patch 5/8)
- fixed kdoc warnings (patch 6/8, patch 8/8)

Grzegorz Nitka (8):
  dpll: add generic DPLL type
  dpll: allow registering FW-identified pin with a different DPLL
  dpll: extend pin notifier and netlink events with notification source
    ID
  dpll: zl3073x: allow SyncE_Ref pin state change
  ice: introduce TXC DPLL device and TX ref clock pin framework for E825
  ice: implement CPI support for E825C
  ice: add Tx reference clock index handling to AN restart command
  ice: implement E825 TX ref clock control and TXC hardware sync status

 .../devicetree/bindings/dpll/dpll-device.yaml |   2 +-
 Documentation/netlink/specs/dpll.yaml         |   3 +
 drivers/dpll/dpll_core.c                      |  32 +-
 drivers/dpll/dpll_core.h                      |   3 +-
 drivers/dpll/dpll_netlink.c                   |  10 +-
 drivers/dpll/dpll_netlink.h                   |   4 +-
 drivers/dpll/dpll_nl.c                        |   2 +-
 drivers/dpll/zl3073x/prop.c                   |   9 +
 drivers/net/ethernet/intel/ice/Makefile       |   2 +-
 drivers/net/ethernet/intel/ice/ice.h          |  12 +
 drivers/net/ethernet/intel/ice/ice_adapter.c  |   4 +
 drivers/net/ethernet/intel/ice/ice_adapter.h  |   7 +
 .../net/ethernet/intel/ice/ice_adminq_cmd.h   |   2 +
 drivers/net/ethernet/intel/ice/ice_common.c   |   5 +-
 drivers/net/ethernet/intel/ice/ice_common.h   |   2 +-
 drivers/net/ethernet/intel/ice/ice_cpi.c      | 364 +++++++++++++++++
 drivers/net/ethernet/intel/ice/ice_cpi.h      |  61 +++
 drivers/net/ethernet/intel/ice/ice_dpll.c     | 380 ++++++++++++++++--
 drivers/net/ethernet/intel/ice/ice_dpll.h     |  10 +
 drivers/net/ethernet/intel/ice/ice_lib.c      |   3 +-
 drivers/net/ethernet/intel/ice/ice_ptp.c      |  26 +-
 drivers/net/ethernet/intel/ice/ice_ptp.h      |   7 +
 drivers/net/ethernet/intel/ice/ice_ptp_hw.c   |  37 ++
 drivers/net/ethernet/intel/ice/ice_ptp_hw.h   |  34 ++
 drivers/net/ethernet/intel/ice/ice_sbq_cmd.h  |   5 +-
 drivers/net/ethernet/intel/ice/ice_txclk.c    | 251 ++++++++++++
 drivers/net/ethernet/intel/ice/ice_txclk.h    |  38 ++
 drivers/net/ethernet/intel/ice/ice_type.h     |   2 +
 include/linux/dpll.h                          |   1 +
 include/uapi/linux/dpll.h                     |   2 +
 30 files changed, 1266 insertions(+), 54 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/ice/ice_cpi.c
 create mode 100644 drivers/net/ethernet/intel/ice/ice_cpi.h
 create mode 100644 drivers/net/ethernet/intel/ice/ice_txclk.c
 create mode 100644 drivers/net/ethernet/intel/ice/ice_txclk.h


base-commit: 790ead9394860e7d70c5e0e50a35b243e909a618
-- 
2.39.3