From: Daniel Hua daniel.hua@ni.com
[ Upstream commit 3a53285228165225a7f76c7d5ff1ddc0213ce0e4 ]
Problem description: After ethernet cable connect and disconnect for several iterations on a device with i210, tx timestamp will stop being put into the socket.
Steps to reproduce: 1. Setup a device with i210 and wire it to a 802.1AS capable switch ( Extreme Networks Summit x440 is used in our case) 2. Have the gptp daemon running on the device and make sure it is synced with the switch 3. Have the switch disable and enable the port, wait for the device gets resynced with the switch 4. Iterates step 3 until the device is not albe to get resynced 5. Review the log in dmesg and you will see warning message "igb : clearing Tx timestamp hang"
Root cause: If ptp_tx_work() gets scheduled just before the port gets disabled, a LINK DOWN event will be processed before ptp_tx_work(), which may cause timeout in ptp_tx_work(). In the timeout logic, the TSYNCTXCTL's TXTT bit (Transmit timestamp valid bit) is not cleared, causing no new timestamp loaded to TXSTMP register. Consequently therefore, no new interrupt is triggerred by TSICR.TXTS bit and no more Tx timestamp send to the socket.
Signed-off-by: Daniel Hua daniel.hua@ni.com Tested-by: Aaron Brown aaron.f.brown@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/net/ethernet/intel/igb/igb_ptp.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c index 841c2a083349..0746b19ec6d3 100644 --- a/drivers/net/ethernet/intel/igb/igb_ptp.c +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c @@ -643,6 +643,10 @@ static void igb_ptp_tx_work(struct work_struct *work) adapter->ptp_tx_skb = NULL; clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state); adapter->tx_hwtstamp_timeouts++; + /* Clear the tx valid bit in TSYNCTXCTL register to enable + * interrupt + */ + rd32(E1000_TXSTMPH); dev_warn(&adapter->pdev->dev, "clearing Tx timestamp hang\n"); return; } @@ -717,6 +721,7 @@ void igb_ptp_rx_hang(struct igb_adapter *adapter) */ void igb_ptp_tx_hang(struct igb_adapter *adapter) { + struct e1000_hw *hw = &adapter->hw; bool timeout = time_is_before_jiffies(adapter->ptp_tx_start + IGB_PTP_TX_TIMEOUT);
@@ -736,6 +741,10 @@ void igb_ptp_tx_hang(struct igb_adapter *adapter) adapter->ptp_tx_skb = NULL; clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state); adapter->tx_hwtstamp_timeouts++; + /* Clear the tx valid bit in TSYNCTXCTL register to enable + * interrupt + */ + rd32(E1000_TXSTMPH); dev_warn(&adapter->pdev->dev, "clearing Tx timestamp hang\n"); } }