net: dsa: mv88e6xxx: add rx/tx timestamping support

This patch implements RX/TX timestamping support.

The Marvell PTP hardware supports RX timestamping individual message
types, but for simplicity we only support the EVENT receive filter since
few if any clients bother with the more specific filter types.

checkpatch and reverse Christmas tree changes by Andrew Lunn.

Re-factor duplicated code paths and avoid IfOk anti-pattern, use the
common ptp worker thread from the class layer and time stamp UDP/IPv4
frames as well as Layer-2 frame by Richard Cochran.

Signed-off-by: Brandon Streiff <brandon.streiff@ni.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/Makefile

@@ -7,6 +7,7 @@ mv88e6xxx-objs += global1_vtu.o
 mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_GLOBAL2) += global2.o
 mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_GLOBAL2) += global2_avb.o
 mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_GLOBAL2) += global2_scratch.o
+mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_PTP) += hwtstamp.o
 mv88e6xxx-objs += phy.o
 mv88e6xxx-objs += port.o
 mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_PTP) += ptp.o

drivers/net/dsa/mv88e6xxx/chip.c

@@ -36,6 +36,7 @@
 #include "chip.h"
 #include "global1.h"
 #include "global2.h"
+#include "hwtstamp.h"
 #include "phy.h"
 #include "port.h"
 #include "ptp.h"
@@ -2093,11 +2094,15 @@ static int mv88e6xxx_setup(struct dsa_switch *ds)
 	if (err)
 		goto unlock;
 
-	/* Setup PTP Hardware Clock */
+	/* Setup PTP Hardware Clock and timestamping */
 	if (chip->info->ptp_support) {
 		err = mv88e6xxx_ptp_setup(chip);
 		if (err)
 			goto unlock;
+
+		err = mv88e6xxx_hwtstamp_setup(chip);
+		if (err)
+			goto unlock;
 	}
 
 unlock:
@@ -3932,6 +3937,11 @@ static const struct dsa_switch_ops mv88e6xxx_switch_ops = {
 	.port_mdb_del           = mv88e6xxx_port_mdb_del,
 	.crosschip_bridge_join	= mv88e6xxx_crosschip_bridge_join,
 	.crosschip_bridge_leave	= mv88e6xxx_crosschip_bridge_leave,
+	.port_hwtstamp_set	= mv88e6xxx_port_hwtstamp_set,
+	.port_hwtstamp_get	= mv88e6xxx_port_hwtstamp_get,
+	.port_txtstamp		= mv88e6xxx_port_txtstamp,
+	.port_rxtstamp		= mv88e6xxx_port_rxtstamp,
+	.get_ts_info		= mv88e6xxx_get_ts_info,
 };
 
 static struct dsa_switch_driver mv88e6xxx_switch_drv = {
@@ -4074,8 +4084,10 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
 	struct dsa_switch *ds = dev_get_drvdata(&mdiodev->dev);
 	struct mv88e6xxx_chip *chip = ds->priv;
 
-	if (chip->info->ptp_support)
+	if (chip->info->ptp_support) {
+		mv88e6xxx_hwtstamp_free(chip);
 		mv88e6xxx_ptp_free(chip);
+	}
 
 	mv88e6xxx_phy_destroy(chip);
 	mv88e6xxx_unregister_switch(chip);

drivers/net/dsa/mv88e6xxx/chip.h

@@ -164,6 +164,32 @@ struct mv88e6xxx_irq {
 	unsigned int nirqs;
 };
 
+/* state flags for mv88e6xxx_port_hwtstamp::state */
+enum {
+	MV88E6XXX_HWTSTAMP_ENABLED,
+	MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS,
+};
+
+struct mv88e6xxx_port_hwtstamp {
+	/* Port index */
+	int port_id;
+
+	/* Timestamping state */
+	unsigned long state;
+
+	/* Resources for receive timestamping */
+	struct sk_buff_head rx_queue;
+	struct sk_buff_head rx_queue2;
+
+	/* Resources for transmit timestamping */
+	unsigned long tx_tstamp_start;
+	struct sk_buff *tx_skb;
+	u16 tx_seq_id;
+
+	/* Current timestamp configuration */
+	struct hwtstamp_config tstamp_config;
+};
+
 struct mv88e6xxx_chip {
 	const struct mv88e6xxx_info *info;
 
@@ -236,6 +262,9 @@ struct mv88e6xxx_chip {
 	struct ptp_pin_desc	pin_config[MV88E6XXX_MAX_GPIO];
 	u16 trig_config;
 	u16 evcap_config;
+
+	/* Per-port timestamping resources. */
+	struct mv88e6xxx_port_hwtstamp port_hwtstamp[DSA_MAX_PORTS];
 };
 
 struct mv88e6xxx_bus_ops {