net: lan966x: Don't read RX timestamp if not needed

Whenever a frame was received to the CPU, the HW is timestamping the
frame. In the IFH(Inter Frame Header) it is found the nanosecond part
of the timestamps the SW is required to read from HW the second part.
But reading the second part it seems to be a expensive operations, so
so change this such to read the second part only when rx filter is
enabled.
Doing this change gives the RX a performance boost of ~70mbit.

before:
[  5]   0.00-10.01  sec   546 MBytes   457 Mbits/sec    0 sender

now:
[  5]   0.00-10.01  sec   652 MBytes   530 Mbits/sec    0 sender
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c

@@ -517,7 +517,7 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx,
 	if (likely(!(skb->dev->features & NETIF_F_RXFCS)))
 		skb_trim(skb, skb->len - ETH_FCS_LEN);
 
-	lan966x_ptp_rxtstamp(lan966x, skb, timestamp);
+	lan966x_ptp_rxtstamp(lan966x, skb, src_port, timestamp);
 	skb->protocol = eth_type_trans(skb, skb->dev);
 
 	if (lan966x->bridge_mask & BIT(src_port)) {

drivers/net/ethernet/microchip/lan966x/lan966x_main.c

@@ -668,7 +668,7 @@ static irqreturn_t lan966x_xtr_irq_handler(int irq, void *args)
 			*buf = val;
 		}
 
-		lan966x_ptp_rxtstamp(lan966x, skb, timestamp);
+		lan966x_ptp_rxtstamp(lan966x, skb, src_port, timestamp);
 		skb->protocol = eth_type_trans(skb, dev);
 
 		if (lan966x->bridge_mask & BIT(src_port)) {

drivers/net/ethernet/microchip/lan966x/lan966x_main.h

@@ -407,7 +407,8 @@ struct lan966x_port {
 	struct phy *serdes;
 	struct fwnode_handle *fwnode;
 
-	u8 ptp_cmd;
+	u8 ptp_tx_cmd;
+	bool ptp_rx_cmd;
 	u16 ts_id;
 	struct sk_buff_head tx_skbs;
 
@@ -527,7 +528,7 @@ void lan966x_ptp_deinit(struct lan966x *lan966x);
 int lan966x_ptp_hwtstamp_set(struct lan966x_port *port, struct ifreq *ifr);
 int lan966x_ptp_hwtstamp_get(struct lan966x_port *port, struct ifreq *ifr);
 void lan966x_ptp_rxtstamp(struct lan966x *lan966x, struct sk_buff *skb,
-			  u64 timestamp);
+			  u64 src_port, u64 timestamp);
 int lan966x_ptp_txtstamp_request(struct lan966x_port *port,
 				 struct sk_buff *skb);
 void lan966x_ptp_txtstamp_release(struct lan966x_port *port,

drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c

@@ -272,13 +272,13 @@ int lan966x_ptp_hwtstamp_set(struct lan966x_port *port, struct ifreq *ifr)
 
 	switch (cfg.tx_type) {
 	case HWTSTAMP_TX_ON:
-		port->ptp_cmd = IFH_REW_OP_TWO_STEP_PTP;
+		port->ptp_tx_cmd = IFH_REW_OP_TWO_STEP_PTP;
 		break;
 	case HWTSTAMP_TX_ONESTEP_SYNC:
-		port->ptp_cmd = IFH_REW_OP_ONE_STEP_PTP;
+		port->ptp_tx_cmd = IFH_REW_OP_ONE_STEP_PTP;
 		break;
 	case HWTSTAMP_TX_OFF:
-		port->ptp_cmd = IFH_REW_OP_NOOP;
+		port->ptp_tx_cmd = IFH_REW_OP_NOOP;
 		break;
 	default:
 		return -ERANGE;
@@ -286,6 +286,7 @@ int lan966x_ptp_hwtstamp_set(struct lan966x_port *port, struct ifreq *ifr)
 
 	switch (cfg.rx_filter) {
 	case HWTSTAMP_FILTER_NONE:
+		port->ptp_rx_cmd = false;
 		break;
 	case HWTSTAMP_FILTER_ALL:
 	case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
@@ -301,6 +302,7 @@ int lan966x_ptp_hwtstamp_set(struct lan966x_port *port, struct ifreq *ifr)
 	case HWTSTAMP_FILTER_PTP_V2_SYNC:
 	case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
 	case HWTSTAMP_FILTER_NTP_ALL:
+		port->ptp_rx_cmd = true;
 		cfg.rx_filter = HWTSTAMP_FILTER_ALL;
 		break;
 	default:
@@ -332,7 +334,7 @@ static int lan966x_ptp_classify(struct lan966x_port *port, struct sk_buff *skb)
 	u8 msgtype;
 	int type;
 
-	if (port->ptp_cmd == IFH_REW_OP_NOOP)
+	if (port->ptp_tx_cmd == IFH_REW_OP_NOOP)
 		return IFH_REW_OP_NOOP;
 
 	type = ptp_classify_raw(skb);
@@ -343,7 +345,7 @@ static int lan966x_ptp_classify(struct lan966x_port *port, struct sk_buff *skb)
 	if (!header)
 		return IFH_REW_OP_NOOP;
 
-	if (port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
+	if (port->ptp_tx_cmd == IFH_REW_OP_TWO_STEP_PTP)
 		return IFH_REW_OP_TWO_STEP_PTP;
 
 	/* If it is sync and run 1 step then set the correct operation,
@@ -1009,9 +1011,6 @@ static int lan966x_ptp_phc_init(struct lan966x *lan966x,
 	phc->index = index;
 	phc->lan966x = lan966x;
 
-	/* PTP Rx stamping is always enabled.  */
-	phc->hwtstamp_config.rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
-
 	return 0;
 }
 
@@ -1088,14 +1087,15 @@ void lan966x_ptp_deinit(struct lan966x *lan966x)
 }
 
 void lan966x_ptp_rxtstamp(struct lan966x *lan966x, struct sk_buff *skb,
-			  u64 timestamp)
+			  u64 src_port, u64 timestamp)
 {
 	struct skb_shared_hwtstamps *shhwtstamps;
 	struct lan966x_phc *phc;
 	struct timespec64 ts;
 	u64 full_ts_in_ns;
 
-	if (!lan966x->ptp)
+	if (!lan966x->ptp ||
+	    !lan966x->ports[src_port]->ptp_rx_cmd)
 		return;
 
 	phc = &lan966x->phc[LAN966X_PHC_PORT];