netdev - [PATCH net-next 1/7] ice: Check for PTP HW lock more frequently

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Date:   Mon, 14 Nov 2022 15:42:44 -0800
From:   Tony Nguyen <anthony.l.nguyen@...el.com>
To:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        edumazet@...gle.com
Cc:     Karol Kolacinski <karol.kolacinski@...el.com>,
        netdev@...r.kernel.org, anthony.l.nguyen@...el.com,
        richardcochran@...il.com, Gurucharan G <gurucharanx.g@...el.com>
Subject: [PATCH net-next 1/7] ice: Check for PTP HW lock more frequently

From: Karol Kolacinski <karol.kolacinski@...el.com>

It was observed that PTP HW semaphore can be held for ~50 ms in worst
case.
SW should wait longer and check more frequently if the HW lock is held.

Signed-off-by: Karol Kolacinski <karol.kolacinski@...el.com>
Tested-by: Gurucharan G <gurucharanx.g@...el.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@...el.com>
---
 drivers/net/ethernet/intel/ice/ice_ptp_hw.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp_hw.c b/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
index 772b1f566d6e..1f8dd50db524 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
@@ -2963,16 +2963,18 @@ bool ice_ptp_lock(struct ice_hw *hw)
 	u32 hw_lock;
 	int i;
 
-#define MAX_TRIES 5
+#define MAX_TRIES 15
 
 	for (i = 0; i < MAX_TRIES; i++) {
 		hw_lock = rd32(hw, PFTSYN_SEM + (PFTSYN_SEM_BYTES * hw->pf_id));
 		hw_lock = hw_lock & PFTSYN_SEM_BUSY_M;
-		if (!hw_lock)
-			break;
+		if (hw_lock) {
+			/* Somebody is holding the lock */
+			usleep_range(5000, 6000);
+			continue;
+		}
 
-		/* Somebody is holding the lock */
-		usleep_range(10000, 20000);
+		break;
 	}
 
 	return !hw_lock;
-- 
2.35.1