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>

1 files changed, 571 insertions, 0 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.c b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
new file mode 100644
index 000000000000..1b8f79b2c939
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
@@ -0,0 +1,571 @@
+/*
+ * Marvell 88E6xxx Switch hardware timestamping support
+ *
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * Copyright (c) 2017 National Instruments
+ *      Erik Hons <erik.hons@ni.com>
+ *      Brandon Streiff <brandon.streiff@ni.com>
+ *      Dane Wagner <dane.wagner@ni.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include "chip.h"
+#include "global2.h"
+#include "hwtstamp.h"
+#include "ptp.h"
+#include <linux/ptp_classify.h>
+
+#define SKB_PTP_TYPE(__skb) (*(unsigned int *)((__skb)->cb))
+
+static int mv88e6xxx_port_ptp_read(struct mv88e6xxx_chip *chip, int port,
+				   int addr, u16 *data, int len)
+{
+	if (!chip->info->ops->avb_ops->port_ptp_read)
+		return -EOPNOTSUPP;
+
+	return chip->info->ops->avb_ops->port_ptp_read(chip, port, addr,
+						       data, len);
+}
+
+static int mv88e6xxx_port_ptp_write(struct mv88e6xxx_chip *chip, int port,
+				    int addr, u16 data)
+{
+	if (!chip->info->ops->avb_ops->port_ptp_write)
+		return -EOPNOTSUPP;
+
+	return chip->info->ops->avb_ops->port_ptp_write(chip, port, addr,
+							data);
+}
+
+static int mv88e6xxx_ptp_write(struct mv88e6xxx_chip *chip, int addr,
+			       u16 data)
+{
+	if (!chip->info->ops->avb_ops->ptp_write)
+		return -EOPNOTSUPP;
+
+	return chip->info->ops->avb_ops->ptp_write(chip, addr, data);
+}
+
+/* TX_TSTAMP_TIMEOUT: This limits the time spent polling for a TX
+ * timestamp. When working properly, hardware will produce a timestamp
+ * within 1ms. Software may enounter delays due to MDIO contention, so
+ * the timeout is set accordingly.
+ */
+#define TX_TSTAMP_TIMEOUT	msecs_to_jiffies(20)
+
+int mv88e6xxx_get_ts_info(struct dsa_switch *ds, int port,
+			  struct ethtool_ts_info *info)
+{
+	struct mv88e6xxx_chip *chip = ds->priv;
+
+	if (!chip->info->ptp_support)
+		return -EOPNOTSUPP;
+
+	info->so_timestamping =
+		SOF_TIMESTAMPING_TX_HARDWARE |
+		SOF_TIMESTAMPING_RX_HARDWARE |
+		SOF_TIMESTAMPING_RAW_HARDWARE;
+	info->phc_index = ptp_clock_index(chip->ptp_clock);
+	info->tx_types =
+		(1 << HWTSTAMP_TX_OFF) |
+		(1 << HWTSTAMP_TX_ON);
+	info->rx_filters =
+		(1 << HWTSTAMP_FILTER_NONE) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_L4_EVENT) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_L4_SYNC) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_L2_EVENT) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_L2_SYNC) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
+		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ);
+
+	return 0;
+}
+
+static int mv88e6xxx_set_hwtstamp_config(struct mv88e6xxx_chip *chip, int port,
+					 struct hwtstamp_config *config)
+{
+	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
+	bool tstamp_enable = false;
+	u16 port_config0;
+	int err;
+
+	/* Prevent the TX/RX paths from trying to interact with the
+	 * timestamp hardware while we reconfigure it.
+	 */
+	clear_bit_unlock(MV88E6XXX_HWTSTAMP_ENABLED, &ps->state);
+
+	/* reserved for future extensions */
+	if (config->flags)
+		return -EINVAL;
+
+	switch (config->tx_type) {
+	case HWTSTAMP_TX_OFF:
+		tstamp_enable = false;
+		break;
+	case HWTSTAMP_TX_ON:
+		tstamp_enable = true;
+		break;
+	default:
+		return -ERANGE;
+	}
+
+	/* The switch supports timestamping both L2 and L4; one cannot be
+	 * disabled independently of the other.
+	 */
+	switch (config->rx_filter) {
+	case HWTSTAMP_FILTER_NONE:
+		tstamp_enable = false;
+		break;
+	case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
+	case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
+	case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
+	case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
+	case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
+	case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
+	case HWTSTAMP_FILTER_PTP_V2_EVENT:
+	case HWTSTAMP_FILTER_PTP_V2_SYNC:
+	case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
+		config->rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
+		break;
+	case HWTSTAMP_FILTER_ALL:
+	default:
+		config->rx_filter = HWTSTAMP_FILTER_NONE;
+		return -ERANGE;
+	}
+
+	if (tstamp_enable) {
+		/* Disable transportSpecific value matching, so that packets
+		 * with either 1588 (0) and 802.1AS (1) will be timestamped.
+		 */
+		port_config0 = MV88E6XXX_PORT_PTP_CFG0_DISABLE_TSPEC_MATCH;
+	} else {
+		/* Disable PTP. This disables both RX and TX timestamping. */
+		port_config0 = MV88E6XXX_PORT_PTP_CFG0_DISABLE_PTP;
+	}
+
+	mutex_lock(&chip->reg_lock);
+	err = mv88e6xxx_port_ptp_write(chip, port, MV88E6XXX_PORT_PTP_CFG0,
+				       port_config0);
+	mutex_unlock(&chip->reg_lock);
+
+	if (err < 0)
+		return err;
+
+	/* Once hardware has been configured, enable timestamp checks
+	 * in the RX/TX paths.
+	 */
+	if (tstamp_enable)
+		set_bit(MV88E6XXX_HWTSTAMP_ENABLED, &ps->state);
+
+	return 0;
+}
+
+int mv88e6xxx_port_hwtstamp_set(struct dsa_switch *ds, int port,
+				struct ifreq *ifr)
+{
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
+	struct hwtstamp_config config;
+	int err;
+
+	if (!chip->info->ptp_support)
+		return -EOPNOTSUPP;
+
+	if (port < 0 || port >= mv88e6xxx_num_ports(chip))
+		return -EINVAL;
+
+	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
+		return -EFAULT;
+
+	err = mv88e6xxx_set_hwtstamp_config(chip, port, &config);
+	if (err)
+		return err;
+
+	/* Save the chosen configuration to be returned later. */
+	memcpy(&ps->tstamp_config, &config, sizeof(config));
+
+	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
+		-EFAULT : 0;
+}
+
+int mv88e6xxx_port_hwtstamp_get(struct dsa_switch *ds, int port,
+				struct ifreq *ifr)
+{
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
+	struct hwtstamp_config *config = &ps->tstamp_config;
+
+	if (!chip->info->ptp_support)
+		return -EOPNOTSUPP;
+
+	if (port < 0 || port >= mv88e6xxx_num_ports(chip))
+		return -EINVAL;
+
+	return copy_to_user(ifr->ifr_data, config, sizeof(*config)) ?
+		-EFAULT : 0;
+}
+
+/* Get the start of the PTP header in this skb */
+static u8 *parse_ptp_header(struct sk_buff *skb, unsigned int type)
+{
+	u8 *data = skb_mac_header(skb);
+	unsigned int offset = 0;
+
+	if (type & PTP_CLASS_VLAN)
+		offset += VLAN_HLEN;
+
+	switch (type & PTP_CLASS_PMASK) {
+	case PTP_CLASS_IPV4:
+		offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
+		break;
+	case PTP_CLASS_IPV6:
+		offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
+		break;
+	case PTP_CLASS_L2:
+		offset += ETH_HLEN;
+		break;
+	default:
+		return NULL;
+	}
+
+	/* Ensure that the entire header is present in this packet. */
+	if (skb->len + ETH_HLEN < offset + 34)
+		return NULL;
+
+	return data + offset;
+}
+
+/* Returns a pointer to the PTP header if the caller should time stamp,
+ * or NULL if the caller should not.
+ */
+static u8 *mv88e6xxx_should_tstamp(struct mv88e6xxx_chip *chip, int port,
+				   struct sk_buff *skb, unsigned int type)
+{
+	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
+	u8 *hdr;
+
+	if (!chip->info->ptp_support)
+		return NULL;
+
+	if (port < 0 || port >= mv88e6xxx_num_ports(chip))
+		return NULL;
+
+	hdr = parse_ptp_header(skb, type);
+	if (!hdr)
+		return NULL;
+
+	if (!test_bit(MV88E6XXX_HWTSTAMP_ENABLED, &ps->state))
+		return NULL;
+
+	return hdr;
+}
+
+static int mv88e6xxx_ts_valid(u16 status)
+{
+	if (!(status & MV88E6XXX_PTP_TS_VALID))
+		return 0;
+	if (status & MV88E6XXX_PTP_TS_STATUS_MASK)
+		return 0;
+	return 1;
+}
+
+static int seq_match(struct sk_buff *skb, u16 ts_seqid)
+{
+	unsigned int type = SKB_PTP_TYPE(skb);
+	u8 *hdr = parse_ptp_header(skb, type);
+	__be16 *seqid;
+
+	seqid = (__be16 *)(hdr + OFF_PTP_SEQUENCE_ID);
+
+	return ts_seqid == ntohs(*seqid);
+}
+
+static void mv88e6xxx_get_rxts(struct mv88e6xxx_chip *chip,
+			       struct mv88e6xxx_port_hwtstamp *ps,
+			       struct sk_buff *skb, u16 reg,
+			       struct sk_buff_head *rxq)
+{
+	u16 buf[4] = { 0 }, status, timelo, timehi, seq_id;
+	struct skb_shared_hwtstamps *shwt;
+	int err;
+
+	mutex_lock(&chip->reg_lock);
+	err = mv88e6xxx_port_ptp_read(chip, ps->port_id,
+				      reg, buf, ARRAY_SIZE(buf));
+	mutex_unlock(&chip->reg_lock);
+	if (err)
+		pr_err("failed to get the receive time stamp\n");
+
+	status = buf[0];
+	timelo = buf[1];
+	timehi = buf[2];
+	seq_id = buf[3];
+
+	if (status & MV88E6XXX_PTP_TS_VALID) {
+		mutex_lock(&chip->reg_lock);
+		err = mv88e6xxx_port_ptp_write(chip, ps->port_id, reg, 0);
+		mutex_unlock(&chip->reg_lock);
+		if (err)
+			pr_err("failed to clear the receive status\n");
+	}
+	/* Since the device can only handle one time stamp at a time,
+	 * we purge any extra frames from the queue.
+	 */
+	for ( ; skb; skb = skb_dequeue(rxq)) {
+		if (mv88e6xxx_ts_valid(status) && seq_match(skb, seq_id)) {
+			u64 ns = timehi << 16 | timelo;
+
+			mutex_lock(&chip->reg_lock);
+			ns = timecounter_cyc2time(&chip->tstamp_tc, ns);
+			mutex_unlock(&chip->reg_lock);
+			shwt = skb_hwtstamps(skb);
+			memset(shwt, 0, sizeof(*shwt));
+			shwt->hwtstamp = ns_to_ktime(ns);
+			status &= ~MV88E6XXX_PTP_TS_VALID;
+		}
+		netif_rx_ni(skb);
+	}
+}
+
+static void mv88e6xxx_rxtstamp_work(struct mv88e6xxx_chip *chip,
+				    struct mv88e6xxx_port_hwtstamp *ps)
+{
+	struct sk_buff *skb;
+
+	skb = skb_dequeue(&ps->rx_queue);
+
+	if (skb)
+		mv88e6xxx_get_rxts(chip, ps, skb, MV88E6XXX_PORT_PTP_ARR0_STS,
+				   &ps->rx_queue);
+
+	skb = skb_dequeue(&ps->rx_queue2);
+	if (skb)
+		mv88e6xxx_get_rxts(chip, ps, skb, MV88E6XXX_PORT_PTP_ARR1_STS,
+				   &ps->rx_queue2);
+}
+
+static int is_pdelay_resp(u8 *msgtype)
+{
+	return (*msgtype & 0xf) == 3;
+}
+
+bool mv88e6xxx_port_rxtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb, unsigned int type)
+{
+	struct mv88e6xxx_port_hwtstamp *ps;
+	struct mv88e6xxx_chip *chip;
+	u8 *hdr;
+
+	chip = ds->priv;
+	ps = &chip->port_hwtstamp[port];
+
+	if (ps->tstamp_config.rx_filter != HWTSTAMP_FILTER_PTP_V2_EVENT)
+		return false;
+
+	hdr = mv88e6xxx_should_tstamp(chip, port, skb, type);
+	if (!hdr)
+		return false;
+
+	SKB_PTP_TYPE(skb) = type;
+
+	if (is_pdelay_resp(hdr))
+		skb_queue_tail(&ps->rx_queue2, skb);
+	else
+		skb_queue_tail(&ps->rx_queue, skb);
+
+	ptp_schedule_worker(chip->ptp_clock, 0);
+
+	return true;
+}
+
+static int mv88e6xxx_txtstamp_work(struct mv88e6xxx_chip *chip,
+				   struct mv88e6xxx_port_hwtstamp *ps)
+{
+	struct skb_shared_hwtstamps shhwtstamps;
+	u16 departure_block[4], status;
+	struct sk_buff *tmp_skb;
+	u32 time_raw;
+	int err;
+	u64 ns;
+
+	if (!ps->tx_skb)
+		return 0;
+
+	mutex_lock(&chip->reg_lock);
+	err = mv88e6xxx_port_ptp_read(chip, ps->port_id,
+				      MV88E6XXX_PORT_PTP_DEP_STS,
+				      departure_block,
+				      ARRAY_SIZE(departure_block));
+	mutex_unlock(&chip->reg_lock);
+
+	if (err)
+		goto free_and_clear_skb;
+
+	if (!(departure_block[0] & MV88E6XXX_PTP_TS_VALID)) {
+		if (time_is_before_jiffies(ps->tx_tstamp_start +
+					   TX_TSTAMP_TIMEOUT)) {
+			dev_warn(chip->dev, "p%d: clearing tx timestamp hang\n",
+				 ps->port_id);
+			goto free_and_clear_skb;
+		}
+		/* The timestamp should be available quickly, while getting it
+		 * is high priority and time bounded to only 10ms. A poll is
+		 * warranted so restart the work.
+		 */
+		return 1;
+	}
+
+	/* We have the timestamp; go ahead and clear valid now */
+	mutex_lock(&chip->reg_lock);
+	mv88e6xxx_port_ptp_write(chip, ps->port_id,
+				 MV88E6XXX_PORT_PTP_DEP_STS, 0);
+	mutex_unlock(&chip->reg_lock);
+
+	status = departure_block[0] & MV88E6XXX_PTP_TS_STATUS_MASK;
+	if (status != MV88E6XXX_PTP_TS_STATUS_NORMAL) {
+		dev_warn(chip->dev, "p%d: tx timestamp overrun\n", ps->port_id);
+		goto free_and_clear_skb;
+	}
+
+	if (departure_block[3] != ps->tx_seq_id) {
+		dev_warn(chip->dev, "p%d: unexpected seq. id\n", ps->port_id);
+		goto free_and_clear_skb;
+	}
+
+	memset(&shhwtstamps, 0, sizeof(shhwtstamps));
+	time_raw = ((u32)departure_block[2] << 16) | departure_block[1];
+	mutex_lock(&chip->reg_lock);
+	ns = timecounter_cyc2time(&chip->tstamp_tc, time_raw);
+	mutex_unlock(&chip->reg_lock);
+	shhwtstamps.hwtstamp = ns_to_ktime(ns);
+
+	dev_dbg(chip->dev,
+		"p%d: txtstamp %llx status 0x%04x skb ID 0x%04x hw ID 0x%04x\n",
+		ps->port_id, ktime_to_ns(shhwtstamps.hwtstamp),
+		departure_block[0], ps->tx_seq_id, departure_block[3]);
+
+	/* skb_complete_tx_timestamp() will free up the client to make
+	 * another timestamp-able transmit. We have to be ready for it
+	 * -- by clearing the ps->tx_skb "flag" -- beforehand.
+	 */
+
+	tmp_skb = ps->tx_skb;
+	ps->tx_skb = NULL;
+	clear_bit_unlock(MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS, &ps->state);
+	skb_complete_tx_timestamp(tmp_skb, &shhwtstamps);
+
+	return 0;
+
+free_and_clear_skb:
+	dev_kfree_skb_any(ps->tx_skb);
+	ps->tx_skb = NULL;
+	clear_bit_unlock(MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS, &ps->state);
+
+	return 0;
+}
+
+long mv88e6xxx_hwtstamp_work(struct ptp_clock_info *ptp)
+{
+	struct mv88e6xxx_chip *chip = ptp_to_chip(ptp);
+	struct dsa_switch *ds = chip->ds;
+	struct mv88e6xxx_port_hwtstamp *ps;
+	int i, restart = 0;
+
+	for (i = 0; i < ds->num_ports; i++) {
+		if (!dsa_is_user_port(ds, i))
+			continue;
+
+		ps = &chip->port_hwtstamp[i];
+		if (test_bit(MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS, &ps->state))
+			restart |= mv88e6xxx_txtstamp_work(chip, ps);
+
+		mv88e6xxx_rxtstamp_work(chip, ps);
+	}
+
+	return restart ? 1 : -1;
+}
+
+bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *clone, unsigned int type)
+{
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
+	__be16 *seq_ptr;
+	u8 *hdr;
+
+	if (!(skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP))
+		return false;
+
+	hdr = mv88e6xxx_should_tstamp(chip, port, clone, type);
+	if (!hdr)
+		return false;
+
+	seq_ptr = (__be16 *)(hdr + OFF_PTP_SEQUENCE_ID);
+
+	if (test_and_set_bit_lock(MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS,
+				  &ps->state))
+		return false;
+
+	ps->tx_skb = clone;
+	ps->tx_tstamp_start = jiffies;
+	ps->tx_seq_id = be16_to_cpup(seq_ptr);
+
+	ptp_schedule_worker(chip->ptp_clock, 0);
+	return true;
+}
+
+static int mv88e6xxx_hwtstamp_port_setup(struct mv88e6xxx_chip *chip, int port)
+{
+	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
+
+	ps->port_id = port;
+
+	skb_queue_head_init(&ps->rx_queue);
+	skb_queue_head_init(&ps->rx_queue2);
+
+	return mv88e6xxx_port_ptp_write(chip, port, MV88E6XXX_PORT_PTP_CFG0,
+					MV88E6XXX_PORT_PTP_CFG0_DISABLE_PTP);
+}
+
+int mv88e6xxx_hwtstamp_setup(struct mv88e6xxx_chip *chip)
+{
+	int err;
+	int i;
+
+	/* Disable timestamping on all ports. */
+	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
+		err = mv88e6xxx_hwtstamp_port_setup(chip, i);
+		if (err)
+			return err;
+	}
+
+	/* MV88E6XXX_PTP_MSG_TYPE is a mask of PTP message types to
+	 * timestamp. This affects all ports that have timestamping enabled,
+	 * but the timestamp config is per-port; thus we configure all events
+	 * here and only support the HWTSTAMP_FILTER_*_EVENT filter types.
+	 */
+	err = mv88e6xxx_ptp_write(chip, MV88E6XXX_PTP_MSGTYPE,
+				  MV88E6XXX_PTP_MSGTYPE_ALL_EVENT);
+	if (err)
+		return err;
+
+	/* Use ARRIVAL1 for peer delay response messages. */
+	err = mv88e6xxx_ptp_write(chip, MV88E6XXX_PTP_TS_ARRIVAL_PTR,
+				  MV88E6XXX_PTP_MSGTYPE_PDLAY_RES);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+void mv88e6xxx_hwtstamp_free(struct mv88e6xxx_chip *chip)
+{
+}