From 144ed1763003c6a88a4b788cc5da1d8a1ddf061f Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Wed, 5 Oct 2016 09:30:42 -0700 Subject: [PATCH] i40e: correct check for reading TSYNINDX from the receive descriptor When hardware has taken a timestamp for a received packet, it indicates which RXTIME register the timestamp was placed in by some bits in the receive descriptor. It uses 3 bits, one to indicate if the descriptor index is valid (ie: there was a timestamp) and 2 bits to indicate which of the 4 registers to read. However, the driver currently does not check the TSYNVALID bit and only checks the index. It assumes a zero index means no timestamp, and a non zero index means a timestamp occurred. While this appears to be true, it prevents ever reading a timestamp in RXTIME[0], and causes the first timestamp the device captures to be ignored. Fix this by using the TSYNVALID bit correctly as the true indicator of whether the packet has an associated timestamp. Also rename the variable rsyn to tsyn as this is more descriptive and matches the register names. Change-ID: I4437e8f3a3df2c2ddb458b0fb61420f3dafc4c12 Signed-off-by: Jacob Keller Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index daade4fe80d6..c9eb6b852d66 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -1410,11 +1410,12 @@ void i40e_process_skb_fields(struct i40e_ring *rx_ring, u64 qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len); u32 rx_status = (qword & I40E_RXD_QW1_STATUS_MASK) >> I40E_RXD_QW1_STATUS_SHIFT; - u32 rsyn = (rx_status & I40E_RXD_QW1_STATUS_TSYNINDX_MASK) >> + u32 tsynvalid = rx_status & I40E_RXD_QW1_STATUS_TSYNVALID_MASK; + u32 tsyn = (rx_status & I40E_RXD_QW1_STATUS_TSYNINDX_MASK) >> I40E_RXD_QW1_STATUS_TSYNINDX_SHIFT; - if (unlikely(rsyn)) { - i40e_ptp_rx_hwtstamp(rx_ring->vsi->back, skb, rsyn); + if (unlikely(tsynvalid)) { + i40e_ptp_rx_hwtstamp(rx_ring->vsi->back, skb, tsyn); rx_ring->last_rx_timestamp = jiffies; } -- 2.20.1