net: mscc: ocelot: support PTP Sync one-step timestamping

Although HWTSTAMP_TX_ONESTEP_SYNC existed in ioctl for hardware timestamp
configuration, the PTP Sync one-step timestamping had never been supported.

This patch is to truely support it. The hardware timestamp request type is
stored in DSA_SKB_CB_PRIV first byte per skb, so that corresponding
configuration could be done during transmitting. Non-onestep-Sync packet
with one-step timestamp request should fall back to use two-step timestamp.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>

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"
@@ -546,19 +547,75 @@ static void ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,
 	spin_unlock(&ocelot_port->ts_id_lock);
 }
 
+bool ocelot_ptp_rew_op(struct sk_buff *skb, struct sk_buff *clone, u32 *rew_op)
+{
+	/* For two-step timestamp, retrieve ptp_cmd in DSA_SKB_CB_PRIV
+	 * and timestamp ID in clone->cb[0].
+	 * For one-step timestamp, retrieve ptp_cmd in DSA_SKB_CB_PRIV.
+	 */
+	u8 *ptp_cmd = DSA_SKB_CB_PRIV(skb);
+
+	if (clone) {
+		*rew_op = *ptp_cmd;
+		*rew_op |= clone->cb[0] << 3;
+	} else if (*ptp_cmd) {
+		*rew_op = *ptp_cmd;
+	} else {
+		return false;
+	}
+
+	return true;
+}
+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 first byte of DSA_SKB_CB_PRIV per skb */
+	if (ptp_cmd == IFH_REW_OP_ORIGIN_PTP) {
+		if (ocelot_ptp_is_onestep_sync(skb)) {
+			*(u8 *)DSA_SKB_CB_PRIV(skb) = 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);
+		*(u8 *)DSA_SKB_CB_PRIV(skb) = ptp_cmd;
 	}
 
 	return 0;

drivers/net/ethernet/mscc/ocelot_net.c

@@ -514,10 +514,7 @@ static netdev_tx_t ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
 			return NETDEV_TX_OK;
 		}
 
-		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
-			rew_op = ocelot_port->ptp_cmd;
-			rew_op |= clone->cb[0] << 3;
-		}
+		ocelot_ptp_rew_op(skb, clone, &rew_op);
 	}
 
 	ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);

include/soc/mscc/ocelot.h

@@ -820,6 +820,7 @@ 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);
+bool ocelot_ptp_rew_op(struct sk_buff *skb, struct sk_buff *clone, u32 *rew_op);
 int ocelot_port_txtstamp_request(struct ocelot *ocelot, int port,
 				 struct sk_buff *skb,
 				 struct sk_buff **clone);

net/dsa/tag_ocelot.c

@@ -5,25 +5,6 @@
 #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)
 {
@@ -32,6 +13,7 @@ static void ocelot_xmit_common(struct sk_buff *skb, struct net_device *netdev,
 	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 +24,8 @@ 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);
+	if (ocelot_ptp_rew_op(skb, clone, &rew_op))
+		ocelot_ifh_set_rew_op(injection, rew_op);
 
 	*ifh = injection;
 }

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)
 {
@@ -47,10 +21,17 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 	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;
+
+	if (ocelot_ptp_rew_op(skb, clone, &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));