1 files changed, 41 insertions, 7 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
index 726579c0098c..30061598912b 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
@@ -658,6 +658,9 @@ static bool ice_ptp_tx_tstamp(struct ice_ptp_tx *tx)
 	struct ice_ptp_port *ptp_port;
 	bool ts_handled = true;
 	struct ice_pf *pf;
+	struct ice_hw *hw;
+	u64 tstamp_ready;
+	int err;
 	u8 idx;
 
 	if (!tx->init)
@@ -665,6 +668,12 @@ static bool ice_ptp_tx_tstamp(struct ice_ptp_tx *tx)
 
 	ptp_port = container_of(tx, struct ice_ptp_port, tx);
 	pf = ptp_port_to_pf(ptp_port);
+	hw = &pf->hw;
+
+	/* Read the Tx ready status first */
+	err = ice_get_phy_tx_tstamp_ready(hw, tx->block, &tstamp_ready);
+	if (err)
+		return false;
 
 	for_each_set_bit(idx, tx->in_use, tx->len) {
 		struct skb_shared_hwtstamps shhwtstamps = {};
@@ -672,7 +681,6 @@ static bool ice_ptp_tx_tstamp(struct ice_ptp_tx *tx)
 		u64 raw_tstamp = 0, tstamp;
 		bool drop_ts = false;
 		struct sk_buff *skb;
-		int err;
 
 		/* Drop packets which have waited for more than 2 seconds */
 		if (time_is_before_jiffies(tx->tstamps[idx].start + 2 * HZ)) {
@@ -680,27 +688,47 @@ static bool ice_ptp_tx_tstamp(struct ice_ptp_tx *tx)
 
 			/* Count the number of Tx timestamps that timed out */
 			pf->ptp.tx_hwtstamp_timeouts++;
+		}
 
-			goto skip_ts_read;
+		/* Only read a timestamp from the PHY if its marked as ready
+		 * by the tstamp_ready register. This avoids unnecessary
+		 * reading of timestamps which are not yet valid. This is
+		 * important as we must read all timestamps which are valid
+		 * and only timestamps which are valid during each interrupt.
+		 * If we do not, the hardware logic for generating a new
+		 * interrupt can get stuck on some devices.
+		 */
+		if (!(tstamp_ready & BIT_ULL(phy_idx))) {
+			if (drop_ts)
+				goto skip_ts_read;
+
+			continue;
 		}
 
 		ice_trace(tx_tstamp_fw_req, tx->tstamps[idx].skb, idx);
 
-		err = ice_read_phy_tstamp(&pf->hw, tx->block, phy_idx,
-					  &raw_tstamp);
+		err = ice_read_phy_tstamp(hw, tx->block, phy_idx, &raw_tstamp);
 		if (err)
 			continue;
 
 		ice_trace(tx_tstamp_fw_done, tx->tstamps[idx].skb, idx);
 
-		/* Check if the timestamp is invalid or stale */
-		if (!(raw_tstamp & ICE_PTP_TS_VALID) ||
+		/* For PHYs which don't implement a proper timestamp ready
+		 * bitmap, verify that the timestamp value is different
+		 * from the last cached timestamp. If it is not, skip this for
+		 * now assuming it hasn't yet been captured by hardware.
+		 */
+		if (!drop_ts && tx->verify_cached &&
 		    raw_tstamp == tx->tstamps[idx].cached_tstamp)
 			continue;
 
+		/* Discard any timestamp value without the valid bit set */
+		if (!(raw_tstamp & ICE_PTP_TS_VALID))
+			drop_ts = true;
+
 skip_ts_read:
 		spin_lock(&tx->lock);
-		if (raw_tstamp)
+		if (tx->verify_cached && raw_tstamp)
 			tx->tstamps[idx].cached_tstamp = raw_tstamp;
 		clear_bit(idx, tx->in_use);
 		skb = tx->tstamps[idx].skb;
@@ -836,6 +864,7 @@ ice_ptp_init_tx_e822(struct ice_pf *pf, struct ice_ptp_tx *tx, u8 port)
 	tx->block = port / ICE_PORTS_PER_QUAD;
 	tx->offset = (port % ICE_PORTS_PER_QUAD) * INDEX_PER_PORT_E822;
 	tx->len = INDEX_PER_PORT_E822;
+	tx->verify_cached = 0;
 
 	return ice_ptp_alloc_tx_tracker(tx);
 }
@@ -854,6 +883,11 @@ ice_ptp_init_tx_e810(struct ice_pf *pf, struct ice_ptp_tx *tx)
 	tx->block = pf->hw.port_info->lport;
 	tx->offset = 0;
 	tx->len = INDEX_PER_PORT_E810;
+	/* The E810 PHY does not provide a timestamp ready bitmap. Instead,
+	 * verify new timestamps against cached copy of the last read
+	 * timestamp.
+	 */
+	tx->verify_cached = 1;
 
 	return ice_ptp_alloc_tx_tracker(tx);
 }