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Commit 0066c8b6 authored by Kshitiz Gupta's avatar Kshitiz Gupta Committed by Jeff Kirsher
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igb: fix adjusting PTP timestamps for Tx/Rx latency 



Fix PHY delay compensation math in igb_ptp_tx_hwtstamp() and
igb_ptp_rx_rgtstamp. Add PHY delay compensation in
igb_ptp_rx_pktstamp().

In the IGB driver, there are two functions that retrieve timestamps
received by the PHY - igb_ptp_rx_rgtstamp() and igb_ptp_rx_pktstamp().
The previous commit only changed igb_ptp_rx_rgtstamp(), and the change
was incorrect.

There are two instances in which PHY delay compensations should be
made:

- Before the packet transmission over the PHY, the latency between
  when the packet is timestamped and transmission of the packets,
  should be an add operation, but it is currently a subtract.

- After the packets are received from the PHY, the latency between
  the receiving and timestamping of the packets should be a subtract
  operation, but it is currently an add.

Signed-off-by: default avatarKshitiz Gupta <kshitiz.gupta@ni.com>
Fixes: 3f544d2a (igb: adjust ptp timestamps for tx/rx latency)
Tested-by: default avatarAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent a1560dd7

drivers/net/ethernet/intel/igb/igb_ptp.c

+23 −3
Original line number Diff line number Diff line
@@ -744,7 +744,8 @@ static void igb_ptp_tx_hwtstamp(struct igb_adapter *adapter) 
		}

	}



	shhwtstamps.hwtstamp = ktime_sub_ns(shhwtstamps.hwtstamp, adjust);

	shhwtstamps.hwtstamp =

		ktime_add_ns(shhwtstamps.hwtstamp, adjust);



	skb_tstamp_tx(adapter->ptp_tx_skb, &shhwtstamps);

	dev_kfree_skb_any(adapter->ptp_tx_skb);
@@ -767,13 +768,32 @@ void igb_ptp_rx_pktstamp(struct igb_q_vector *q_vector, 
			 struct sk_buff *skb)

{

	__le64 *regval = (__le64 *)va;

	struct igb_adapter *adapter = q_vector->adapter;

	int adjust = 0;



	/* The timestamp is recorded in little endian format.

	 * DWORD: 0        1        2        3

	 * Field: Reserved Reserved SYSTIML  SYSTIMH

	 */

	igb_ptp_systim_to_hwtstamp(q_vector->adapter, skb_hwtstamps(skb),

	igb_ptp_systim_to_hwtstamp(adapter, skb_hwtstamps(skb),

				   le64_to_cpu(regval[1]));



	/* adjust timestamp for the RX latency based on link speed */

	if (adapter->hw.mac.type == e1000_i210) {

		switch (adapter->link_speed) {

		case SPEED_10:

			adjust = IGB_I210_RX_LATENCY_10;

			break;

		case SPEED_100:

			adjust = IGB_I210_RX_LATENCY_100;

			break;

		case SPEED_1000:

			adjust = IGB_I210_RX_LATENCY_1000;

			break;

		}

	}

	skb_hwtstamps(skb)->hwtstamp =

		ktime_sub_ns(skb_hwtstamps(skb)->hwtstamp, adjust);

}



/**
@@ -825,7 +845,7 @@ void igb_ptp_rx_rgtstamp(struct igb_q_vector *q_vector, 
		}

	}

	skb_hwtstamps(skb)->hwtstamp =

		ktime_add_ns(skb_hwtstamps(skb)->hwtstamp, adjust);

		ktime_sub_ns(skb_hwtstamps(skb)->hwtstamp, adjust);



	/* Update the last_rx_timestamp timer in order to enable watchdog check

	 * for error case of latched timestamp on a dropped packet.