Merge branch 'ocelot-ptp'

Yangbo Lu says:

====================
Support Ocelot PTP Sync one-step timestamping

This patch-set is to support Ocelot PTP Sync one-step timestamping.
Actually before that, this patch-set cleans up and optimizes the
DSA slave tx timestamp request handling process.

Changes for v2:
	- Split tx timestamp optimization patch.
	- Updated doc patch.
	- Freed skb->cb usage in dsa core driver, and moved to device
	  drivers.
	- Other minor fixes.
Changes for v3:
	- Switched sequence of patch #3 and #4 with rebasing to fix build.
	- Replaced hard coded 48 of memset(skb->cb, 0, 48) with sizeof().
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

18 files changed, 230 insertions, 180 deletions

diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst
index f682e88fa87e..7db3985359bc 100644
--- a/Documentation/networking/timestamping.rst
+++ b/Documentation/networking/timestamping.rst
@@ -630,30 +630,45 @@ hardware timestamping on it. This is because the SO_TIMESTAMPING API does not
 allow the delivery of multiple hardware timestamps for the same packet, so
 anybody else except for the DSA switch port must be prevented from doing so.
 
-In code, DSA provides for most of the infrastructure for timestamping already,
-in generic code: a BPF classifier (``ptp_classify_raw``) is used to identify
-PTP event messages (any other packets, including PTP general messages, are not
-timestamped), and provides two hooks to drivers:
-
-- ``.port_txtstamp()``: The driver is passed a clone of the timestampable skb
-  to be transmitted, before actually transmitting it. Typically, a switch will
-  have a PTP TX timestamp register (or sometimes a FIFO) where the timestamp
-  becomes available. There may be an IRQ that is raised upon this timestamp's
-  availability, or the driver might have to poll after invoking
-  ``dev_queue_xmit()`` towards the host interface. Either way, in the
-  ``.port_txtstamp()`` method, the driver only needs to save the clone for
-  later use (when the timestamp becomes available). Each skb is annotated with
-  a pointer to its clone, in ``DSA_SKB_CB(skb)->clone``, to ease the driver's
-  job of keeping track of which clone belongs to which skb.
-
-- ``.port_rxtstamp()``: The original (and only) timestampable skb is provided
-  to the driver, for it to annotate it with a timestamp, if that is immediately
-  available, or defer to later. On reception, timestamps might either be
-  available in-band (through metadata in the DSA header, or attached in other
-  ways to the packet), or out-of-band (through another RX timestamping FIFO).
-  Deferral on RX is typically necessary when retrieving the timestamp needs a
-  sleepable context. In that case, it is the responsibility of the DSA driver
-  to call ``netif_rx_ni()`` on the freshly timestamped skb.
+In the generic layer, DSA provides the following infrastructure for PTP
+timestamping:
+
+- ``.port_txtstamp()``: a hook called prior to the transmission of
+  packets with a hardware TX timestamping request from user space.
+  This is required for two-step timestamping, since the hardware
+  timestamp becomes available after the actual MAC transmission, so the
+  driver must be prepared to correlate the timestamp with the original
+  packet so that it can re-enqueue the packet back into the socket's
+  error queue. To save the packet for when the timestamp becomes
+  available, the driver can call ``skb_clone_sk`` , save the clone pointer
+  in skb->cb and enqueue a tx skb queue. Typically, a switch will have a
+  PTP TX timestamp register (or sometimes a FIFO) where the timestamp
+  becomes available. In case of a FIFO, the hardware might store
+  key-value pairs of PTP sequence ID/message type/domain number and the
+  actual timestamp. To perform the correlation correctly between the
+  packets in a queue waiting for timestamping and the actual timestamps,
+  drivers can use a BPF classifier (``ptp_classify_raw``) to identify
+  the PTP transport type, and ``ptp_parse_header`` to interpret the PTP
+  header fields. There may be an IRQ that is raised upon this
+  timestamp's availability, or the driver might have to poll after
+  invoking ``dev_queue_xmit()`` towards the host interface.
+  One-step TX timestamping do not require packet cloning, since there is
+  no follow-up message required by the PTP protocol (because the
+  TX timestamp is embedded into the packet by the MAC), and therefore
+  user space does not expect the packet annotated with the TX timestamp
+  to be re-enqueued into its socket's error queue.
+
+- ``.port_rxtstamp()``: On RX, the BPF classifier is run by DSA to
+  identify PTP event messages (any other packets, including PTP general
+  messages, are not timestamped). The original (and only) timestampable
+  skb is provided to the driver, for it to annotate it with a timestamp,
+  if that is immediately available, or defer to later. On reception,
+  timestamps might either be available in-band (through metadata in the
+  DSA header, or attached in other ways to the packet), or out-of-band
+  (through another RX timestamping FIFO). Deferral on RX is typically
+  necessary when retrieving the timestamp needs a sleepable context. In
+  that case, it is the responsibility of the DSA driver to call
+  ``netif_rx_ni()`` on the freshly timestamped skb.
 
 3.2.2 Ethernet PHYs
 ^^^^^^^^^^^^^^^^^^^
diff --git a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
index 69dd9a2e8bb6..40b41c794dfa 100644
--- a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
+++ b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
@@ -373,30 +373,38 @@ long hellcreek_hwtstamp_work(struct ptp_clock_info *ptp)
 	return restart ? 1 : -1;
 }
 
-bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone, unsigned int type)
+void hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb)
 {
 	struct hellcreek *hellcreek = ds->priv;
 	struct hellcreek_port_hwtstamp *ps;
 	struct ptp_header *hdr;
+	struct sk_buff *clone;
+	unsigned int type;
 
 	ps = &hellcreek->ports[port].port_hwtstamp;
 
-	/* Check if the driver is expected to do HW timestamping */
-	if (!(skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP))
-		return false;
+	type = ptp_classify_raw(skb);
+	if (type == PTP_CLASS_NONE)
+		return;
 
 	/* Make sure the message is a PTP message that needs to be timestamped
 	 * and the interaction with the HW timestamping is enabled. If not, stop
 	 * here
 	 */
-	hdr = hellcreek_should_tstamp(hellcreek, port, clone, type);
+	hdr = hellcreek_should_tstamp(hellcreek, port, skb, type);
 	if (!hdr)
-		return false;
+		return;
+
+	clone = skb_clone_sk(skb);
+	if (!clone)
+		return;
 
 	if (test_and_set_bit_lock(HELLCREEK_HWTSTAMP_TX_IN_PROGRESS,
-				  &ps->state))
-		return false;
+				  &ps->state)) {
+		kfree_skb(clone);
+		return;
+	}
 
 	ps->tx_skb = clone;
 
@@ -406,8 +414,6 @@ bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
 	ps->tx_tstamp_start = jiffies;
 
 	ptp_schedule_worker(hellcreek->ptp_clock, 0);
-
-	return true;
 }
 
 bool hellcreek_port_rxtstamp(struct dsa_switch *ds, int port,
diff --git a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h
index c0745ffa1ebb..71af77efb28b 100644
--- a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h
+++ b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h
@@ -44,8 +44,8 @@ int hellcreek_port_hwtstamp_get(struct dsa_switch *ds, int port,
 
 bool hellcreek_port_rxtstamp(struct dsa_switch *ds, int port,
 			     struct sk_buff *clone, unsigned int type);
-bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone, unsigned int type);
+void hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb);
 
 int hellcreek_get_ts_info(struct dsa_switch *ds, int port,
 			  struct ethtool_ts_info *info);
diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.c b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
index 094d17a1d037..8f74ffc7a279 100644
--- a/drivers/net/dsa/mv88e6xxx/hwtstamp.c
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
@@ -468,30 +468,38 @@ long mv88e6xxx_hwtstamp_work(struct ptp_clock_info *ptp)
 	return restart ? 1 : -1;
 }
 
-bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone, unsigned int type)
+void mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
 	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
 	struct ptp_header *hdr;
+	struct sk_buff *clone;
+	unsigned int type;
 
-	if (!(skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP))
-		return false;
+	type = ptp_classify_raw(skb);
+	if (type == PTP_CLASS_NONE)
+		return;
 
-	hdr = mv88e6xxx_should_tstamp(chip, port, clone, type);
+	hdr = mv88e6xxx_should_tstamp(chip, port, skb, type);
 	if (!hdr)
-		return false;
+		return;
+
+	clone = skb_clone_sk(skb);
+	if (!clone)
+		return;
 
 	if (test_and_set_bit_lock(MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS,
-				  &ps->state))
-		return false;
+				  &ps->state)) {
+		kfree_skb(clone);
+		return;
+	}
 
 	ps->tx_skb = clone;
 	ps->tx_tstamp_start = jiffies;
 	ps->tx_seq_id = be16_to_cpu(hdr->sequence_id);
 
 	ptp_schedule_worker(chip->ptp_clock, 0);
-	return true;
 }
 
 int mv88e6165_global_disable(struct mv88e6xxx_chip *chip)
diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.h b/drivers/net/dsa/mv88e6xxx/hwtstamp.h
index 9da9f197ba02..cf7fb6d660b1 100644
--- a/drivers/net/dsa/mv88e6xxx/hwtstamp.h
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.h
@@ -117,8 +117,8 @@ int mv88e6xxx_port_hwtstamp_get(struct dsa_switch *ds, int port,
 
 bool mv88e6xxx_port_rxtstamp(struct dsa_switch *ds, int port,
 			     struct sk_buff *clone, unsigned int type);
-bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone, unsigned int type);
+void mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb);
 
 int mv88e6xxx_get_ts_info(struct dsa_switch *ds, int port,
 			  struct ethtool_ts_info *info);
@@ -151,11 +151,9 @@ static inline bool mv88e6xxx_port_rxtstamp(struct dsa_switch *ds, int port,
 	return false;
 }
 
-static inline bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
-					   struct sk_buff *clone,
-					   unsigned int type)
+static inline void mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
+					   struct sk_buff *skb)
 {
-	return false;
 }
 
 static inline int mv88e6xxx_get_ts_info(struct dsa_switch *ds, int port,
diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 6b5442be0230..ce607fbaaa3a 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -1395,19 +1395,20 @@ static bool felix_rxtstamp(struct dsa_switch *ds, int port,
 	return false;
 }
 
-static bool felix_txtstamp(struct dsa_switch *ds, int port,
-			   struct sk_buff *clone, unsigned int type)
+static void felix_txtstamp(struct dsa_switch *ds, int port,
+			   struct sk_buff *skb)
 {
 	struct ocelot *ocelot = ds->priv;
-	struct ocelot_port *ocelot_port = ocelot->ports[port];
+	struct sk_buff *clone = NULL;
 
-	if (ocelot->ptp && (skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP) &&
-	    ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
-		ocelot_port_add_txtstamp_skb(ocelot, port, clone);
-		return true;
-	}
+	if (!ocelot->ptp)
+		return;
 
-	return false;
+	if (ocelot_port_txtstamp_request(ocelot, port, skb, &clone))
+		return;
+
+	if (clone)
+		OCELOT_SKB_CB(skb)->clone = clone;
 }
 
 static int felix_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index d9c198ca0197..405024b637d6 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -3137,7 +3137,7 @@ static void sja1105_port_deferred_xmit(struct kthread_work *work)
 	struct sk_buff *skb;
 
 	while ((skb = skb_dequeue(&sp->xmit_queue)) != NULL) {
-		struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
+		struct sk_buff *clone = SJA1105_SKB_CB(skb)->clone;
 
 		mutex_lock(&priv->mgmt_lock);
 
diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.c b/drivers/net/dsa/sja1105/sja1105_ptp.c
index 1b90570b257b..0bc566b9e958 100644
--- a/drivers/net/dsa/sja1105/sja1105_ptp.c
+++ b/drivers/net/dsa/sja1105/sja1105_ptp.c
@@ -431,20 +431,24 @@ bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
 	return true;
 }
 
-/* Called from dsa_skb_tx_timestamp. This callback is just to make DSA clone
- * the skb and have it available in DSA_SKB_CB in the .port_deferred_xmit
+/* Called from dsa_skb_tx_timestamp. This callback is just to clone
+ * the skb and have it available in SJA1105_SKB_CB in the .port_deferred_xmit
  * callback, where we will timestamp it synchronously.
  */
-bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
-			   struct sk_buff *skb, unsigned int type)
+void sja1105_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
 {
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_port *sp = &priv->ports[port];
+	struct sk_buff *clone;
 
 	if (!sp->hwts_tx_en)
-		return false;
+		return;
 
-	return true;
+	clone = skb_clone_sk(skb);
+	if (!clone)
+		return;
+
+	SJA1105_SKB_CB(skb)->clone = clone;
 }
 
 static int sja1105_ptp_reset(struct dsa_switch *ds)
diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.h b/drivers/net/dsa/sja1105/sja1105_ptp.h
index 3daa33e98e77..34f97f58a355 100644
--- a/drivers/net/dsa/sja1105/sja1105_ptp.h
+++ b/drivers/net/dsa/sja1105/sja1105_ptp.h
@@ -104,8 +104,8 @@ void sja1105_ptp_txtstamp_skb(struct dsa_switch *ds, int slot,
 bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
 			   struct sk_buff *skb, unsigned int type);
 
-bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
-			   struct sk_buff *skb, unsigned int type);
+void sja1105_port_txtstamp(struct dsa_switch *ds, int port,
+			   struct sk_buff *skb);
 
 int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr);
 
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 8d06ffaf318a..0c4283319d7f 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -6,6 +6,7 @@
  */
 #include <linux/dsa/ocelot.h>
 #include <linux/if_bridge.h>
+#include <linux/ptp_classify.h>
 #include <soc/mscc/ocelot_vcap.h>
 #include "ocelot.h"
 #include "ocelot_vcap.h"
@@ -530,22 +531,92 @@ void ocelot_port_disable(struct ocelot *ocelot, int port)
 }
 EXPORT_SYMBOL(ocelot_port_disable);
 
-void ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,
-				  struct sk_buff *clone)
+static void ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,
+					 struct sk_buff *clone)
 {
 	struct ocelot_port *ocelot_port = ocelot->ports[port];
 
 	spin_lock(&ocelot_port->ts_id_lock);
 
 	skb_shinfo(clone)->tx_flags |= SKBTX_IN_PROGRESS;
-	/* Store timestamp ID in cb[0] of sk_buff */
-	clone->cb[0] = ocelot_port->ts_id;
+	/* Store timestamp ID in OCELOT_SKB_CB(clone)->ts_id */
+	OCELOT_SKB_CB(clone)->ts_id = ocelot_port->ts_id;
 	ocelot_port->ts_id = (ocelot_port->ts_id + 1) % 4;
 	skb_queue_tail(&ocelot_port->tx_skbs, clone);
 
 	spin_unlock(&ocelot_port->ts_id_lock);
 }
-EXPORT_SYMBOL(ocelot_port_add_txtstamp_skb);
+
+u32 ocelot_ptp_rew_op(struct sk_buff *skb)
+{
+	struct sk_buff *clone = OCELOT_SKB_CB(skb)->clone;
+	u8 ptp_cmd = OCELOT_SKB_CB(skb)->ptp_cmd;
+	u32 rew_op = 0;
+
+	if (ptp_cmd == IFH_REW_OP_TWO_STEP_PTP && clone) {
+		rew_op = ptp_cmd;
+		rew_op |= OCELOT_SKB_CB(clone)->ts_id << 3;
+	} else if (ptp_cmd == IFH_REW_OP_ORIGIN_PTP) {
+		rew_op = ptp_cmd;
+	}
+
+	return rew_op;
+}
+EXPORT_SYMBOL(ocelot_ptp_rew_op);
+
+static bool ocelot_ptp_is_onestep_sync(struct sk_buff *skb)
+{
+	struct ptp_header *hdr;
+	unsigned int ptp_class;
+	u8 msgtype, twostep;
+
+	ptp_class = ptp_classify_raw(skb);
+	if (ptp_class == PTP_CLASS_NONE)
+		return false;
+
+	hdr = ptp_parse_header(skb, ptp_class);
+	if (!hdr)
+		return false;
+
+	msgtype = ptp_get_msgtype(hdr, ptp_class);
+	twostep = hdr->flag_field[0] & 0x2;
+
+	if (msgtype == PTP_MSGTYPE_SYNC && twostep == 0)
+		return true;
+
+	return false;
+}
+
+int ocelot_port_txtstamp_request(struct ocelot *ocelot, int port,
+				 struct sk_buff *skb,
+				 struct sk_buff **clone)
+{
+	struct ocelot_port *ocelot_port = ocelot->ports[port];
+	u8 ptp_cmd = ocelot_port->ptp_cmd;
+
+	/* Store ptp_cmd in OCELOT_SKB_CB(skb)->ptp_cmd */
+	if (ptp_cmd == IFH_REW_OP_ORIGIN_PTP) {
+		if (ocelot_ptp_is_onestep_sync(skb)) {
+			OCELOT_SKB_CB(skb)->ptp_cmd = ptp_cmd;
+			return 0;
+		}
+
+		/* Fall back to two-step timestamping */
+		ptp_cmd = IFH_REW_OP_TWO_STEP_PTP;
+	}
+
+	if (ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
+		*clone = skb_clone_sk(skb);
+		if (!(*clone))
+			return -ENOMEM;
+
+		ocelot_port_add_txtstamp_skb(ocelot, port, *clone);
+		OCELOT_SKB_CB(skb)->ptp_cmd = ptp_cmd;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(ocelot_port_txtstamp_request);
 
 static void ocelot_get_hwtimestamp(struct ocelot *ocelot,
 				   struct timespec64 *ts)
@@ -604,7 +675,7 @@ void ocelot_get_txtstamp(struct ocelot *ocelot)
 		spin_lock_irqsave(&port->tx_skbs.lock, flags);
 
 		skb_queue_walk_safe(&port->tx_skbs, skb, skb_tmp) {
-			if (skb->cb[0] != id)
+			if (OCELOT_SKB_CB(skb)->ts_id != id)
 				continue;
 			__skb_unlink(skb, &port->tx_skbs);
 			skb_match = skb;
diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c
index 36f32a4d9b0f..aad33d22c33f 100644
--- a/drivers/net/ethernet/mscc/ocelot_net.c
+++ b/drivers/net/ethernet/mscc/ocelot_net.c
@@ -507,21 +507,17 @@ static netdev_tx_t ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	/* Check if timestamping is needed */
 	if (ocelot->ptp && (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
-		rew_op = ocelot_port->ptp_cmd;
+		struct sk_buff *clone = NULL;
 
-		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
-			struct sk_buff *clone;
-
-			clone = skb_clone_sk(skb);
-			if (!clone) {
-				kfree_skb(skb);
-				return NETDEV_TX_OK;
-			}
+		if (ocelot_port_txtstamp_request(ocelot, port, skb, &clone)) {
+			kfree_skb(skb);
+			return NETDEV_TX_OK;
+		}
 
-			ocelot_port_add_txtstamp_skb(ocelot, port, clone);
+		if (clone)
+			OCELOT_SKB_CB(skb)->clone = clone;
 
-			rew_op |= clone->cb[0] << 3;
-		}
+		rew_op = ocelot_ptp_rew_op(skb);
 	}
 
 	ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h
index dd93735ae228..1eb84562b311 100644
--- a/include/linux/dsa/sja1105.h
+++ b/include/linux/dsa/sja1105.h
@@ -47,11 +47,12 @@ struct sja1105_tagger_data {
 };
 
 struct sja1105_skb_cb {
+	struct sk_buff *clone;
 	u32 meta_tstamp;
 };
 
 #define SJA1105_SKB_CB(skb) \
-	((struct sja1105_skb_cb *)DSA_SKB_CB_PRIV(skb))
+	((struct sja1105_skb_cb *)((skb)->cb))
 
 struct sja1105_port {
 	u16 subvlan_map[DSA_8021Q_N_SUBVLAN];
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 507082959aa4..e1a2610a0e06 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -117,20 +117,6 @@ struct dsa_netdevice_ops {
 #define MODULE_ALIAS_DSA_TAG_DRIVER(__proto)				\
 	MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __stringify(__proto##_VALUE))
 
-struct dsa_skb_cb {
-	struct sk_buff *clone;
-};
-
-struct __dsa_skb_cb {
-	struct dsa_skb_cb cb;
-	u8 priv[48 - sizeof(struct dsa_skb_cb)];
-};
-
-#define DSA_SKB_CB(skb) ((struct dsa_skb_cb *)((skb)->cb))
-
-#define DSA_SKB_CB_PRIV(skb)			\
-	((void *)(skb)->cb + offsetof(struct __dsa_skb_cb, priv))
-
 struct dsa_switch_tree {
 	struct list_head	list;
 
@@ -740,8 +726,8 @@ struct dsa_switch_ops {
 				     struct ifreq *ifr);
 	int	(*port_hwtstamp_set)(struct dsa_switch *ds, int port,
 				     struct ifreq *ifr);
-	bool	(*port_txtstamp)(struct dsa_switch *ds, int port,
-				 struct sk_buff *clone, unsigned int type);
+	void	(*port_txtstamp)(struct dsa_switch *ds, int port,
+				 struct sk_buff *skb);
 	bool	(*port_rxtstamp)(struct dsa_switch *ds, int port,
 				 struct sk_buff *skb, unsigned int type);
 
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index 68cdc7ceaf4d..2f5ce4d4fdbf 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -689,6 +689,15 @@ struct ocelot_policer {
 	u32 burst; /* bytes */
 };
 
+struct ocelot_skb_cb {
+	struct sk_buff *clone;
+	u8 ptp_cmd;
+	u8 ts_id;
+};
+
+#define OCELOT_SKB_CB(skb) \
+	((struct ocelot_skb_cb *)((skb)->cb))
+
 #define ocelot_read_ix(ocelot, reg, gi, ri) __ocelot_read_ix(ocelot, reg, reg##_GSZ * (gi) + reg##_RSZ * (ri))
 #define ocelot_read_gix(ocelot, reg, gi) __ocelot_read_ix(ocelot, reg, reg##_GSZ * (gi))
 #define ocelot_read_rix(ocelot, reg, ri) __ocelot_read_ix(ocelot, reg, reg##_RSZ * (ri))
@@ -740,15 +749,16 @@ u32 __ocelot_target_read_ix(struct ocelot *ocelot, enum ocelot_target target,
 void __ocelot_target_write_ix(struct ocelot *ocelot, enum ocelot_target target,
 			      u32 val, u32 reg, u32 offset);
 
-/* Packet I/O */
 #if IS_ENABLED(CONFIG_MSCC_OCELOT_SWITCH_LIB)
 
+/* Packet I/O */
 bool ocelot_can_inject(struct ocelot *ocelot, int grp);
 void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 			      u32 rew_op, struct sk_buff *skb);
 int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp, struct sk_buff **skb);
 void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp);
 
+u32 ocelot_ptp_rew_op(struct sk_buff *skb);
 #else
 
 static inline bool ocelot_can_inject(struct ocelot *ocelot, int grp)
@@ -772,6 +782,10 @@ static inline void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp)
 {
 }
 
+static inline u32 ocelot_ptp_rew_op(struct sk_buff *skb)
+{
+	return 0;
+}
 #endif
 
 /* Hardware initialization */
@@ -820,8 +834,9 @@ int ocelot_vlan_add(struct ocelot *ocelot, int port, u16 vid, bool pvid,
 int ocelot_vlan_del(struct ocelot *ocelot, int port, u16 vid);
 int ocelot_hwstamp_get(struct ocelot *ocelot, int port, struct ifreq *ifr);
 int ocelot_hwstamp_set(struct ocelot *ocelot, int port, struct ifreq *ifr);
-void ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,
-				  struct sk_buff *clone);
+int ocelot_port_txtstamp_request(struct ocelot *ocelot, int port,
+				 struct sk_buff *skb,
+				 struct sk_buff **clone);
 void ocelot_get_txtstamp(struct ocelot *ocelot);
 void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu);
 int ocelot_get_max_mtu(struct ocelot *ocelot, int port);
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index cbc2bd643ab2..5baba7021427 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -111,6 +111,8 @@ config NET_DSA_TAG_RTL4_A
 
 config NET_DSA_TAG_OCELOT
 	tristate "Tag driver for Ocelot family of switches, using NPI port"
+	depends on MSCC_OCELOT_SWITCH_LIB || \
+		   (MSCC_OCELOT_SWITCH_LIB=n && COMPILE_TEST)
 	select PACKING
 	help
 	  Say Y or M if you want to enable NPI tagging for the Ocelot switches
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 77b33bd161b8..8c0f3c6ab365 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -20,7 +20,6 @@
 #include <linux/if_bridge.h>
 #include <linux/if_hsr.h>
 #include <linux/netpoll.h>
-#include <linux/ptp_classify.h>
 
 #include "dsa_priv.h"
 
@@ -556,26 +555,14 @@ static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
 				 struct sk_buff *skb)
 {
 	struct dsa_switch *ds = p->dp->ds;
-	struct sk_buff *clone;
-	unsigned int type;
 
-	type = ptp_classify_raw(skb);
-	if (type == PTP_CLASS_NONE)
+	if (!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))
 		return;
 
 	if (!ds->ops->port_txtstamp)
 		return;
 
-	clone = skb_clone_sk(skb);
-	if (!clone)
-		return;
-
-	if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type)) {
-		DSA_SKB_CB(skb)->clone = clone;
-		return;
-	}
-
-	kfree_skb(clone);
+	ds->ops->port_txtstamp(ds, p->dp->index, skb);
 }
 
 netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev)
@@ -627,11 +614,9 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	dev_sw_netstats_tx_add(dev, 1, skb->len);
 
-	DSA_SKB_CB(skb)->clone = NULL;
+	memset(skb->cb, 0, sizeof(skb->cb));
 
-	/* Identify PTP protocol packets, clone them, and pass them to the
-	 * switch driver
-	 */
+	/* Handle tx timestamp if any */
 	dsa_skb_tx_timestamp(p, skb);
 
 	if (dsa_realloc_skb(skb, dev)) {
diff --git a/net/dsa/tag_ocelot.c b/net/dsa/tag_ocelot.c
index f9df9cac81c5..91f0fd1242cd 100644
--- a/net/dsa/tag_ocelot.c
+++ b/net/dsa/tag_ocelot.c
@@ -5,33 +5,14 @@
 #include <soc/mscc/ocelot.h>
 #include "dsa_priv.h"
 
-static void ocelot_xmit_ptp(struct dsa_port *dp, void *injection,
-			    struct sk_buff *clone)
-{
-	struct ocelot *ocelot = dp->ds->priv;
-	struct ocelot_port *ocelot_port;
-	u64 rew_op;
-
-	ocelot_port = ocelot->ports[dp->index];
-	rew_op = ocelot_port->ptp_cmd;
-
-	/* Retrieve timestamp ID populated inside skb->cb[0] of the
-	 * clone by ocelot_port_add_txtstamp_skb
-	 */
-	if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
-		rew_op |= clone->cb[0] << 3;
-
-	ocelot_ifh_set_rew_op(injection, rew_op);
-}
-
 static void ocelot_xmit_common(struct sk_buff *skb, struct net_device *netdev,
 			       __be32 ifh_prefix, void **ifh)
 {
 	struct dsa_port *dp = dsa_slave_to_port(netdev);
-	struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
 	struct dsa_switch *ds = dp->ds;
 	void *injection;
 	__be32 *prefix;
+	u32 rew_op = 0;
 
 	injection = skb_push(skb, OCELOT_TAG_LEN);
 	prefix = skb_push(skb, OCELOT_SHORT_PREFIX_LEN);
@@ -42,9 +23,9 @@ static void ocelot_xmit_common(struct sk_buff *skb, struct net_device *netdev,
 	ocelot_ifh_set_src(injection, ds->num_ports);
 	ocelot_ifh_set_qos_class(injection, skb->priority);
 
-	/* TX timestamping was requested */
-	if (clone)
-		ocelot_xmit_ptp(dp, injection, clone);
+	rew_op = ocelot_ptp_rew_op(skb);
+	if (rew_op)
+		ocelot_ifh_set_rew_op(injection, rew_op);
 
 	*ifh = injection;
 }
diff --git a/net/dsa/tag_ocelot_8021q.c b/net/dsa/tag_ocelot_8021q.c
index 5f3e8e124a82..62a93303bd63 100644
--- a/net/dsa/tag_ocelot_8021q.c
+++ b/net/dsa/tag_ocelot_8021q.c
@@ -13,32 +13,6 @@
 #include <soc/mscc/ocelot_ptp.h>
 #include "dsa_priv.h"
 
-static struct sk_buff *ocelot_xmit_ptp(struct dsa_port *dp,
-				       struct sk_buff *skb,
-				       struct sk_buff *clone)
-{
-	struct ocelot *ocelot = dp->ds->priv;
-	struct ocelot_port *ocelot_port;
-	int port = dp->index;
-	u32 rew_op;
-
-	if (!ocelot_can_inject(ocelot, 0))
-		return NULL;
-
-	ocelot_port = ocelot->ports[port];
-	rew_op = ocelot_port->ptp_cmd;
-
-	/* Retrieve timestamp ID populated inside skb->cb[0] of the
-	 * clone by ocelot_port_add_txtstamp_skb
-	 */
-	if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
-		rew_op |= clone->cb[0] << 3;
-
-	ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
-
-	return NULL;
-}
-
 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 				   struct net_device *netdev)
 {
@@ -46,11 +20,18 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 	u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
 	u16 queue_mapping = skb_get_queue_mapping(skb);
 	u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
-	struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
+	struct ocelot *ocelot = dp->ds->priv;
+	int port = dp->index;
+	u32 rew_op = 0;
+
+	rew_op = ocelot_ptp_rew_op(skb);
+	if (rew_op) {
+		if (!ocelot_can_inject(ocelot, 0))
+			return NULL;
 
-	/* TX timestamping was requested, so inject through MMIO */
-	if (clone)
-		return ocelot_xmit_ptp(dp, skb, clone);
+		ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
+		return NULL;
+	}
 
 	return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
 			      ((pcp << VLAN_PRIO_SHIFT) | tx_vid));