[PATCH net-next v2 1/9] ice: dpll: notify TSPLL lock status from the periodic work only

[Ivan Vecera <ivecera@redhat.com>]

ice_dpll_tspll_state_on_dpll_set() notifies the TSPLL device from a
callback of the TIME_REF pin. This pin belongs to an external DPLL and the
DPLL core is going to run its callbacks under a lock of the pin's owner,
which does not cover the TSPLL device.

Only update dpll_state in the callback, so a device get reports the new
state right away, and leave prev_dpll_state to
ice_dpll_periodic_work_e825(), which then sends the notification. It now
arrives up to 500 ms later and after the reply to the request.

Refresh dpll_state on every run of the work, as the state written by the
callback can be transient and the lock status can return to
prev_dpll_state before the next run. No notification is sent in this case.

Reviewed-by: Petr Oros <poros@redhat.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
Changes in v2:
- Merged the two comments in ice_dpll_tspll_state_on_dpll_set() (Sashiko)
---
 drivers/net/ethernet/intel/ice/ice_dpll.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_dpll.c b/drivers/net/ethernet/intel/ice/ice_dpll.c
index ade1fb3dd06743..0877827a6521cc 100644
--- a/drivers/net/ethernet/intel/ice/ice_dpll.c
+++ b/drivers/net/ethernet/intel/ice/ice_dpll.c
@@ -2914,7 +2914,6 @@ ice_dpll_tspll_state_on_dpll_set(const struct dpll_pin *pin, void *pin_priv,
 	struct ice_dpll_pin *p = pin_priv;
 	struct ice_pf *pf = p->pf;
 	enum ice_clk_src clk_src;
-	bool changed = false;
 	struct ice_dpll *tp;
 	int ret;
 
@@ -2939,23 +2938,16 @@ ice_dpll_tspll_state_on_dpll_set(const struct dpll_pin *pin, void *pin_priv,
 
 		new_state = ice_dpll_tspll_lock_status_get(pf, false);
 
-		/* Sync the cached lock state to what we just observed from HW
-		 * so ice_dpll_periodic_work_e825() (cached path) does not emit
-		 * a spurious UNLOCKED notification between now and the next
-		 * PTP monitor tick.
+		/* Sync the cached lock state to what we just observed from HW.
+		 * ice_dpll_periodic_work_e825() reads it (cached path),
+		 * compares it with prev_dpll_state and sends the notification.
+		 * dpll_state lets a device get report it right away.
 		 */
 		WRITE_ONCE(pf->ptp.tspll_locked,
 			   new_state == DPLL_LOCK_STATUS_LOCKED);
-
-		if (tp->prev_dpll_state != new_state) {
-			tp->dpll_state = new_state;
-			tp->prev_dpll_state = new_state;
-			changed = true;
-		}
+		tp->dpll_state = new_state;
 	}
 	mutex_unlock(&pf->dplls.lock);
-	if (changed)
-		__dpll_device_change_ntf(tp->dpll);
 	/* TSPLL reconfiguration may complete before lock is reacquired.
 	 * PTP periodic monitoring tracks and restores the final lock state.
 	 */
@@ -3372,8 +3364,8 @@ static void ice_dpll_periodic_work_e825(struct ice_pf *pf)
 	mutex_lock(&pf->dplls.lock);
 	new_state = ice_dpll_tspll_lock_status_get(pf, true);
 
+	tp->dpll_state = new_state;
 	if (tp->prev_dpll_state != new_state) {
-		tp->dpll_state = new_state;
 		tp->prev_dpll_state = new_state;
 		changed = true;
 	}
-- 
2.56.0