mlxsw: spectrum: PTP: Support timestamping on Spectrum-1

On Spectrum-1, timestamps arrive through a pair of dedicated events:
MLXSW_TRAP_ID_PTP_ING_FIFO and _EGR_FIFO. The payload delivered with
those traps is contents of the timestamp FIFO at a given port in a given
direction. Add a Spectrum-1-specific handler for these two events which
decodes the timestamps and forwards them to the PTP module.

Add a function that parses a packet, dispatching to ptp_classify_raw(),
and decodes PTP message type, domain number, and sequence ID. Add a new
mlxsw dependency on the PTP classifier.

Add helpers that can store and retrieve unmatched timestamps and SKBs to
the hash table added in a preceding patch.

Add the matching code itself: upon arrival of a timestamp or a packet,
look up the corresponding unmatched entry, and match it up. If there is
none, add a new unmatched entry. This logic is the same on ingress as on
egress.

Packets and timestamps that never matched need to be eventually disposed
of. A garbage collector added in a follow-up patch will take care of
that. Since currently all this code is turned off, no crud will
accumulate in the hash table.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/Kconfig

@@ -84,6 +84,7 @@ config MLXSW_SPECTRUM
 	select OBJAGG
 	select MLXFW
 	imply PTP_1588_CLOCK
+	select NET_PTP_CLASSIFY if PTP_1588_CLOCK
 	default m
 	---help---
 	  This driver supports Mellanox Technologies Spectrum Ethernet

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -3970,6 +3970,46 @@ static void mlxsw_sp_pude_event_func(const struct mlxsw_reg_info *reg,
 	}
 }
 
+static void mlxsw_sp1_ptp_fifo_event_func(struct mlxsw_sp *mlxsw_sp,
+					  char *mtpptr_pl, bool ingress)
+{
+	u8 local_port;
+	u8 num_rec;
+	int i;
+
+	local_port = mlxsw_reg_mtpptr_local_port_get(mtpptr_pl);
+	num_rec = mlxsw_reg_mtpptr_num_rec_get(mtpptr_pl);
+	for (i = 0; i < num_rec; i++) {
+		u8 domain_number;
+		u8 message_type;
+		u16 sequence_id;
+		u64 timestamp;
+
+		mlxsw_reg_mtpptr_unpack(mtpptr_pl, i, &message_type,
+					&domain_number, &sequence_id,
+					&timestamp);
+		mlxsw_sp1_ptp_got_timestamp(mlxsw_sp, ingress, local_port,
+					    message_type, domain_number,
+					    sequence_id, timestamp);
+	}
+}
+
+static void mlxsw_sp1_ptp_ing_fifo_event_func(const struct mlxsw_reg_info *reg,
+					      char *mtpptr_pl, void *priv)
+{
+	struct mlxsw_sp *mlxsw_sp = priv;
+
+	mlxsw_sp1_ptp_fifo_event_func(mlxsw_sp, mtpptr_pl, true);
+}
+
+static void mlxsw_sp1_ptp_egr_fifo_event_func(const struct mlxsw_reg_info *reg,
+					      char *mtpptr_pl, void *priv)
+{
+	struct mlxsw_sp *mlxsw_sp = priv;
+
+	mlxsw_sp1_ptp_fifo_event_func(mlxsw_sp, mtpptr_pl, false);
+}
+
 void mlxsw_sp_rx_listener_no_mark_func(struct sk_buff *skb,
 				       u8 local_port, void *priv)
 {
@@ -4151,6 +4191,9 @@ static const struct mlxsw_listener mlxsw_sp_listener[] = {
 };
 
 static const struct mlxsw_listener mlxsw_sp1_listener[] = {
+	/* Events */
+	MLXSW_EVENTL(mlxsw_sp1_ptp_egr_fifo_event_func, PTP_EGR_FIFO, SP_PTP0),
+	MLXSW_EVENTL(mlxsw_sp1_ptp_ing_fifo_event_func, PTP_ING_FIFO, SP_PTP0),
 };
 
 static int mlxsw_sp_cpu_policers_set(struct mlxsw_core *mlxsw_core)

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -266,6 +266,11 @@ struct mlxsw_sp_port {
 	unsigned acl_rule_count;
 	struct mlxsw_sp_acl_block *ing_acl_block;
 	struct mlxsw_sp_acl_block *eg_acl_block;
+	struct {
+		struct hwtstamp_config hwtstamp_config;
+		u16 ing_types;
+		u16 egr_types;
+	} ptp;
 };
 
 struct mlxsw_sp_port_type_speed_ops {