1 files changed, 102 insertions, 40 deletions

diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c b/drivers/net/ethernet/intel/igc/igc_ptp.c
index 4e10ced736db..32ef112f8291 100644
--- a/drivers/net/ethernet/intel/igc/igc_ptp.c
+++ b/drivers/net/ethernet/intel/igc/igc_ptp.c
@@ -536,9 +536,34 @@ static void igc_ptp_enable_rx_timestamp(struct igc_adapter *adapter)
 	wr32(IGC_TSYNCRXCTL, val);
 }
 
+static void igc_ptp_clear_tx_tstamp(struct igc_adapter *adapter)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&adapter->ptp_tx_lock, flags);
+
+	dev_kfree_skb_any(adapter->ptp_tx_skb);
+	adapter->ptp_tx_skb = NULL;
+
+	spin_unlock_irqrestore(&adapter->ptp_tx_lock, flags);
+}
+
 static void igc_ptp_disable_tx_timestamp(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
+	int i;
+
+	/* Clear the flags first to avoid new packets to be enqueued
+	 * for TX timestamping.
+	 */
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct igc_ring *tx_ring = adapter->tx_ring[i];
+
+		clear_bit(IGC_RING_FLAG_TX_HWTSTAMP, &tx_ring->flags);
+	}
+
+	/* Now we can clean the pending TX timestamp requests. */
+	igc_ptp_clear_tx_tstamp(adapter);
 
 	wr32(IGC_TSYNCTXCTL, 0);
 }
@@ -546,12 +571,23 @@ static void igc_ptp_disable_tx_timestamp(struct igc_adapter *adapter)
 static void igc_ptp_enable_tx_timestamp(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
+	int i;
 
 	wr32(IGC_TSYNCTXCTL, IGC_TSYNCTXCTL_ENABLED | IGC_TSYNCTXCTL_TXSYNSIG);
 
 	/* Read TXSTMP registers to discard any timestamp previously stored. */
 	rd32(IGC_TXSTMPL);
 	rd32(IGC_TXSTMPH);
+
+	/* The hardware is ready to accept TX timestamp requests,
+	 * notify the transmit path.
+	 */
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct igc_ring *tx_ring = adapter->tx_ring[i];
+
+		set_bit(IGC_RING_FLAG_TX_HWTSTAMP, &tx_ring->flags);
+	}
+
 }
 
 /**
@@ -603,6 +639,7 @@ static int igc_ptp_set_timestamp_mode(struct igc_adapter *adapter,
 	return 0;
 }
 
+/* Requires adapter->ptp_tx_lock held by caller. */
 static void igc_ptp_tx_timeout(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
@@ -610,7 +647,6 @@ static void igc_ptp_tx_timeout(struct igc_adapter *adapter)
 	dev_kfree_skb_any(adapter->ptp_tx_skb);
 	adapter->ptp_tx_skb = NULL;
 	adapter->tx_hwtstamp_timeouts++;
-	clear_bit_unlock(__IGC_PTP_TX_IN_PROGRESS, &adapter->state);
 	/* Clear the tx valid bit in TSYNCTXCTL register to enable interrupt. */
 	rd32(IGC_TXSTMPH);
 	netdev_warn(adapter->netdev, "Tx timestamp timeout\n");
@@ -618,20 +654,20 @@ static void igc_ptp_tx_timeout(struct igc_adapter *adapter)
 
 void igc_ptp_tx_hang(struct igc_adapter *adapter)
 {
-	bool timeout = time_is_before_jiffies(adapter->ptp_tx_start +
-					      IGC_PTP_TX_TIMEOUT);
+	unsigned long flags;
 
-	if (!test_bit(__IGC_PTP_TX_IN_PROGRESS, &adapter->state))
-		return;
+	spin_lock_irqsave(&adapter->ptp_tx_lock, flags);
 
-	/* If we haven't received a timestamp within the timeout, it is
-	 * reasonable to assume that it will never occur, so we can unlock the
-	 * timestamp bit when this occurs.
-	 */
-	if (timeout) {
-		cancel_work_sync(&adapter->ptp_tx_work);
-		igc_ptp_tx_timeout(adapter);
-	}
+	if (!adapter->ptp_tx_skb)
+		goto unlock;
+
+	if (time_is_after_jiffies(adapter->ptp_tx_start + IGC_PTP_TX_TIMEOUT))
+		goto unlock;
+
+	igc_ptp_tx_timeout(adapter);
+
+unlock:
+	spin_unlock_irqrestore(&adapter->ptp_tx_lock, flags);
 }
 
 /**
@@ -641,20 +677,57 @@ void igc_ptp_tx_hang(struct igc_adapter *adapter)
  * If we were asked to do hardware stamping and such a time stamp is
  * available, then it must have been for this skb here because we only
  * allow only one such packet into the queue.
+ *
+ * Context: Expects adapter->ptp_tx_lock to be held by caller.
  */
 static void igc_ptp_tx_hwtstamp(struct igc_adapter *adapter)
 {
 	struct sk_buff *skb = adapter->ptp_tx_skb;
 	struct skb_shared_hwtstamps shhwtstamps;
 	struct igc_hw *hw = &adapter->hw;
+	u32 tsynctxctl;
 	int adjust = 0;
 	u64 regval;
 
 	if (WARN_ON_ONCE(!skb))
 		return;
 
-	regval = rd32(IGC_TXSTMPL);
-	regval |= (u64)rd32(IGC_TXSTMPH) << 32;
+	tsynctxctl = rd32(IGC_TSYNCTXCTL);
+	tsynctxctl &= IGC_TSYNCTXCTL_TXTT_0;
+	if (tsynctxctl) {
+		regval = rd32(IGC_TXSTMPL);
+		regval |= (u64)rd32(IGC_TXSTMPH) << 32;
+	} else {
+		/* There's a bug in the hardware that could cause
+		 * missing interrupts for TX timestamping. The issue
+		 * is that for new interrupts to be triggered, the
+		 * IGC_TXSTMPH_0 register must be read.
+		 *
+		 * To avoid discarding a valid timestamp that just
+		 * happened at the "wrong" time, we need to confirm
+		 * that there was no timestamp captured, we do that by
+		 * assuming that no two timestamps in sequence have
+		 * the same nanosecond value.
+		 *
+		 * So, we read the "low" register, read the "high"
+		 * register (to latch a new timestamp) and read the
+		 * "low" register again, if "old" and "new" versions
+		 * of the "low" register are different, a valid
+		 * timestamp was captured, we can read the "high"
+		 * register again.
+		 */
+		u32 txstmpl_old, txstmpl_new;
+
+		txstmpl_old = rd32(IGC_TXSTMPL);
+		rd32(IGC_TXSTMPH);
+		txstmpl_new = rd32(IGC_TXSTMPL);
+
+		if (txstmpl_old == txstmpl_new)
+			return;
+
+		regval = txstmpl_new;
+		regval |= (u64)rd32(IGC_TXSTMPH) << 32;
+	}
 	if (igc_ptp_systim_to_hwtstamp(adapter, &shhwtstamps, regval))
 		return;
 
@@ -676,13 +749,7 @@ static void igc_ptp_tx_hwtstamp(struct igc_adapter *adapter)
 	shhwtstamps.hwtstamp =
 		ktime_add_ns(shhwtstamps.hwtstamp, adjust);
 
-	/* Clear the lock early before calling skb_tstamp_tx so that
-	 * applications are not woken up before the lock bit is clear. We use
-	 * a copy of the skb pointer to ensure other threads can't change it
-	 * while we're notifying the stack.
-	 */
 	adapter->ptp_tx_skb = NULL;
-	clear_bit_unlock(__IGC_PTP_TX_IN_PROGRESS, &adapter->state);
 
 	/* Notify the stack and free the skb after we've unlocked */
 	skb_tstamp_tx(skb, &shhwtstamps);
@@ -690,27 +757,25 @@ static void igc_ptp_tx_hwtstamp(struct igc_adapter *adapter)
 }
 
 /**
- * igc_ptp_tx_work
- * @work: pointer to work struct
+ * igc_ptp_tx_tstamp_event
+ * @adapter: board private structure
  *
- * This work function polls the TSYNCTXCTL valid bit to determine when a
- * timestamp has been taken for the current stored skb.
+ * Called when a TX timestamp interrupt happens to retrieve the
+ * timestamp and send it up to the socket.
  */
-static void igc_ptp_tx_work(struct work_struct *work)
+void igc_ptp_tx_tstamp_event(struct igc_adapter *adapter)
 {
-	struct igc_adapter *adapter = container_of(work, struct igc_adapter,
-						   ptp_tx_work);
-	struct igc_hw *hw = &adapter->hw;
-	u32 tsynctxctl;
+	unsigned long flags;
 
-	if (!test_bit(__IGC_PTP_TX_IN_PROGRESS, &adapter->state))
-		return;
+	spin_lock_irqsave(&adapter->ptp_tx_lock, flags);
 
-	tsynctxctl = rd32(IGC_TSYNCTXCTL);
-	if (WARN_ON_ONCE(!(tsynctxctl & IGC_TSYNCTXCTL_TXTT_0)))
-		return;
+	if (!adapter->ptp_tx_skb)
+		goto unlock;
 
 	igc_ptp_tx_hwtstamp(adapter);
+
+unlock:
+	spin_unlock_irqrestore(&adapter->ptp_tx_lock, flags);
 }
 
 /**
@@ -959,8 +1024,8 @@ void igc_ptp_init(struct igc_adapter *adapter)
 		return;
 	}
 
+	spin_lock_init(&adapter->ptp_tx_lock);
 	spin_lock_init(&adapter->tmreg_lock);
-	INIT_WORK(&adapter->ptp_tx_work, igc_ptp_tx_work);
 
 	adapter->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
 	adapter->tstamp_config.tx_type = HWTSTAMP_TX_OFF;
@@ -1020,10 +1085,7 @@ void igc_ptp_suspend(struct igc_adapter *adapter)
 	if (!(adapter->ptp_flags & IGC_PTP_ENABLED))
 		return;
 
-	cancel_work_sync(&adapter->ptp_tx_work);
-	dev_kfree_skb_any(adapter->ptp_tx_skb);
-	adapter->ptp_tx_skb = NULL;
-	clear_bit_unlock(__IGC_PTP_TX_IN_PROGRESS, &adapter->state);
+	igc_ptp_clear_tx_tstamp(adapter);
 
 	if (pci_device_is_present(adapter->pdev)) {
 		igc_ptp_time_save(adapter);