mlxsw: spectrum: Support time stamping on Spectrum-2

As opposed to Spectrum-1, in which time stamps arrive through a pair of
dedicated events into a queue and later are being matched to the
corresponding packets, in Spectrum-2 we are reading the time stamps
directly from the CQE. Software can get the time stamp in UTC format
using CQEv2.

Add a time stamp field to 'struct mlxsw_skb_cb'. In
mlxsw_pci_cqe_{rdq,sdq}_handle() extract the time stamp from the CQE into
the new time stamp field. Note that the time stamp in the CQE is
represented by 38 bits, which is a short representation of UTC time.
Software should create the full time stamp using the global UTC clock.
Read UTC clock from hardware only for PTP packets which were trapped to CPU
with PTP0 trap ID (event packets).

Use the time stamp from the SKB when packet is received or transmitted.

Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 1 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c
index 0e4bd6315ea5..50527adc5b5a 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/pci.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/pci.c
@@ -513,9 +513,26 @@ static unsigned int mlxsw_pci_read32_off(struct mlxsw_pci *mlxsw_pci,
 	return ioread32be(mlxsw_pci->hw_addr + off);
 }
 
+static void mlxsw_pci_skb_cb_ts_set(struct mlxsw_pci *mlxsw_pci,
+				    struct sk_buff *skb,
+				    enum mlxsw_pci_cqe_v cqe_v, char *cqe)
+{
+	if (cqe_v != MLXSW_PCI_CQE_V2)
+		return;
+
+	if (mlxsw_pci_cqe2_time_stamp_type_get(cqe) !=
+	    MLXSW_PCI_CQE_TIME_STAMP_TYPE_UTC)
+		return;
+
+	mlxsw_skb_cb(skb)->cqe_ts.sec = mlxsw_pci_cqe2_time_stamp_sec_get(cqe);
+	mlxsw_skb_cb(skb)->cqe_ts.nsec =
+		mlxsw_pci_cqe2_time_stamp_nsec_get(cqe);
+}
+
 static void mlxsw_pci_cqe_sdq_handle(struct mlxsw_pci *mlxsw_pci,
 				     struct mlxsw_pci_queue *q,
 				     u16 consumer_counter_limit,
+				     enum mlxsw_pci_cqe_v cqe_v,
 				     char *cqe)
 {
 	struct pci_dev *pdev = mlxsw_pci->pdev;
@@ -535,6 +552,7 @@ static void mlxsw_pci_cqe_sdq_handle(struct mlxsw_pci *mlxsw_pci,
 
 	if (unlikely(!tx_info.is_emad &&
 		     skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
+		mlxsw_pci_skb_cb_ts_set(mlxsw_pci, skb, cqe_v, cqe);
 		mlxsw_core_ptp_transmitted(mlxsw_pci->core, skb,
 					   tx_info.local_port);
 		skb = NULL;
@@ -655,6 +673,8 @@ static void mlxsw_pci_cqe_rdq_handle(struct mlxsw_pci *mlxsw_pci,
 		mlxsw_pci_cqe_rdq_md_tx_port_init(skb, cqe);
 	}
 
+	mlxsw_pci_skb_cb_ts_set(mlxsw_pci, skb, cqe_v, cqe);
+
 	byte_count = mlxsw_pci_cqe_byte_count_get(cqe);
 	if (mlxsw_pci_cqe_crc_get(cqe_v, cqe))
 		byte_count -= ETH_FCS_LEN;
@@ -706,7 +726,7 @@ static void mlxsw_pci_cq_tasklet(struct tasklet_struct *t)
 
 			sdq = mlxsw_pci_sdq_get(mlxsw_pci, dqn);
 			mlxsw_pci_cqe_sdq_handle(mlxsw_pci, sdq,
-						 wqe_counter, ncqe);
+						 wqe_counter, q->u.cq.v, ncqe);
 			q->u.cq.comp_sdq_count++;
 		} else {
 			struct mlxsw_pci_queue *rdq;