RE: [Intel-wired-lan] [PATCH v7 net-next 8/8] ice: implement E825 TX ref clock control and TXC hardware sync status

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf
> Of Grzegorz Nitka
> Sent: Thursday, April 30, 2026 11:43 AM
> To: netdev@xxxxxxxxxxxxxxx
> Cc: Vecera, Ivan <ivecera@xxxxxxxxxx>; vadim.fedorenko@xxxxxxxxx;
> kuba@xxxxxxxxxx; jiri@xxxxxxxxxxx; edumazet@xxxxxxxxxx; Kitszel,
> Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; richardcochran@xxxxxxxxx;
> donald.hunter@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Kubalewski,
> Arkadiusz <arkadiusz.kubalewski@xxxxxxxxx>; andrew+netdev@xxxxxxx;
> intel-wired-lan@xxxxxxxxxxxxxxxx; horms@xxxxxxxxxx;
> Prathosh.Satish@xxxxxxxxxxxxx; Nguyen, Anthony L
> <anthony.l.nguyen@xxxxxxxxx>; pabeni@xxxxxxxxxx; davem@xxxxxxxxxxxxx
> Subject: [Intel-wired-lan] [PATCH v7 net-next 8/8] ice: implement E825
> TX ref clock control and TXC hardware sync status
> 
> Build on the previously introduced TXC DPLL framework and implement
> full TX reference clock control and hardware-backed synchronization
> status reporting for E825 devices.
> 
> E825 firmware may accept or override TX reference clock requests based
> on device-wide routing constraints and link conditions. For this
> reason, TX reference selection and synchronization status must be
> observed from hardware rather than inferred from user intent.
> 
> This change implements TX reference switching using a deferred worker,
> triggered by DPLL TXCLK pin operations. Pin set callbacks express
> selection intent and schedule the operation asynchronously; firmware
> commands and autonegotiation restarts are executed outside of DPLL
> context.
> 
> After link-up, the effective TX reference clock is read back from
> hardware and software state is reconciled accordingly. TXCLK pin state
> reflects only the selected reference clock topology:
> - External references (SYNCE, EREF0) are represented as TXCLK pins
> - The internal ENET/TXCO clock has no pin representation; when
> selected,
>   all TXCLK pins are reported DISCONNECTED
> 
> Actual hardware synchronization result is reported exclusively via the
> TXC DPLL lock status:
> - LOCKED when an external TX reference is in use
> - UNLOCKED when falling back to ENET/TXCO
> 
> This separation allows userspace to distinguish between TX reference
> selection and successful synchronization, matching the DPLL subsystem
> model where pin state describes topology and device lock status
> describes signal quality.
> 
> With this change, TX reference clocks on E825 devices can be reliably
> selected, verified against hardware state, and monitored for effective
> synchronization via standard DPLL interfaces.
> 
> Reviewed-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@xxxxxxxxx>
> Signed-off-by: Grzegorz Nitka <grzegorz.nitka@xxxxxxxxx>
> ---
>  drivers/net/ethernet/intel/ice/Makefile     |   2 +-
>  drivers/net/ethernet/intel/ice/ice.h        |  12 +
>  drivers/net/ethernet/intel/ice/ice_dpll.c   | 110 ++++++++-
>  drivers/net/ethernet/intel/ice/ice_dpll.h   |   4 +
>  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 |  27 +++
> drivers/net/ethernet/intel/ice/ice_txclk.c  | 255 ++++++++++++++++++++
> drivers/net/ethernet/intel/ice/ice_txclk.h  |  38 +++
>  10 files changed, 499 insertions(+), 19 deletions(-)  create mode
> 100644 drivers/net/ethernet/intel/ice/ice_txclk.c
>  create mode 100644 drivers/net/ethernet/intel/ice/ice_txclk.h
> 
> diff --git a/drivers/net/ethernet/intel/ice/Makefile
> b/drivers/net/ethernet/intel/ice/Makefile
> index 38db476ab2ec..95fd0c49800f 100644
> --- a/drivers/net/ethernet/intel/ice/Makefile
> +++ b/drivers/net/ethernet/intel/ice/Makefile
> @@ -54,7 +54,7 @@ ice-$(CONFIG_PCI_IOV) +=	\
>  	ice_vf_mbx.o		\
>  	ice_vf_vsi_vlan_ops.o	\
>  	ice_vf_lib.o

...

> 
> +/**
> + * ice_dpll_txclk_work - apply a pending TX reference clock change
> + * @work: work_struct embedded in struct ice_dplls
> + *
> + * This worker executes an outstanding TX reference clock switch
> +request
> + * that was previously queued via the DPLL TXCLK pin set callback.
> + *
> + * The worker performs only the operational part of the switch,
> issuing
> + * the necessary firmware commands to request a new TX reference
> clock
> + * selection (e.g. triggering an AN restart). It does not verify
> +whether
> + * the requested clock was ultimately accepted by the hardware.
> + *
> + * Hardware verification, software state reconciliation, pin state
> + * notification, and TXC DPLL lock-status updates are performed
> later,
> + * after link-up, by ice_txclk_update_and_notify().
> + *
> + * Context:
> + *   - Runs in process context on pf->dplls.wq and may sleep.
> + *   - Serializes access to shared TXCLK state using pf->dplls.lock.
> + */
> +static void ice_dpll_txclk_work(struct work_struct *work) {
> +	struct ice_dplls *dplls =
> +		container_of(work, struct ice_dplls, txclk_work);
> +	struct ice_pf *pf = container_of(dplls, struct ice_pf, dplls);
> +	enum ice_e825c_ref_clk clk;
> +	bool do_switch;
> +
> +	mutex_lock(&pf->dplls.lock);
> +	do_switch  = pf->dplls.txclk_switch_requested;
Two stray spaces.

> +	clk = pf->ptp.port.tx_clk_req;
> +	pf->dplls.txclk_switch_requested  = false;
Two stray spaces.

> +	mutex_unlock(&pf->dplls.lock);
> +
> +	if (do_switch)
> +		ice_txclk_set_clk(pf, clk);
> +}
> +

...

> --
> 2.39.3