net: dsa: add PTP solution in core driver

Added PTP solution in core driver. Now only gPTP was supported.

- ethernet_api like get_capabilities and get_ptp_clock
  were supported in port driver.

- For TX timestamp, added new dsa_api port_txtstamp for device
  to handle. Device driver might put pkt in queue, and reported
  timestamp after completing transmitting on hardware.

- For RX timestamp, the timestamp could be given to pkt in tag
  driver or device driver.

Signed-off-by: Yangbo Lu <[email protected]>

Author: yangbolu1991

include/zephyr/net/dsa_core.h

@@ -117,6 +117,13 @@ struct dsa_api {
 	/** Port generates random mac address */
 	void (*port_generate_random_mac)(uint8_t *mac_addr);
 
+#if defined(CONFIG_NET_L2_PTP) || defined(__DOXYGEN__)
+	/**
+	 * Port TX timestamp handling
+	 * @kconfig_dep{CONFIG_NET_L2_PTP}
+	 */
+	int (*port_txtstamp)(const struct device *dev, struct net_pkt *pkt);
+#endif
 	/** Switch setup */
 	int (*switch_setup)(const struct dsa_switch_context *dsa_switch_ctx);
 
@@ -142,6 +149,13 @@ struct dsa_port_config {
 	const int tag_proto;
 	/** Ethernet device connected to the port */
 	const struct device *ethernet_connection;
+#if defined(CONFIG_NET_L2_PTP) || defined(__DOXYGEN__)
+	/**
+	 * PTP clock used on the port
+	 * @kconfig_dep{CONFIG_NET_L2_PTP}
+	 */
+	const struct device *ptp_clock;
+#endif
 	/** Instance specific config */
 	void *prv_config;
 };

subsys/net/l2/ethernet/dsa/dsa_core.c

@@ -29,11 +29,42 @@ int dsa_xmit(const struct device *dev, struct net_pkt *pkt)
 	struct net_if *iface_conduit = dsa_switch_ctx->iface_conduit;
 	const struct device *dev_conduit = net_if_get_device(iface_conduit);
 	const struct ethernet_api *eth_api_conduit = dev_conduit->api;
+	struct net_pkt *dsa_pkt;
+	struct net_pkt *clone;
+	int ret;
+
+#ifdef CONFIG_NET_L2_PTP
+	/* Handle TX timestamp if defines */
+	if (ntohs(NET_ETH_HDR(pkt)->type) == NET_ETH_PTYPE_PTP &&
+	    dsa_switch_ctx->dapi->port_txtstamp != NULL) {
+		ret = dsa_switch_ctx->dapi->port_txtstamp(dev, pkt);
+		if (ret != 0) {
+			return ret;
+		}
+	}
+#endif
+	/*
+	 * In case of using TX pkt in other places, pkt should not be changed.
+	 * Here just clone pkt to use for tagging and sending.
+	 * It could be optimized here for performance in the future if some mechanism
+	 * implemented marks whether the pkt data will be accessed or not in other
+	 * places after sending.
+	 */
+	clone = net_pkt_clone(pkt, K_NO_WAIT);
+	if (clone == NULL) {
+		return -ENOBUFS;
+	}
+
 	/* Tag protocol handles pkt first */
-	struct net_pkt *dsa_pkt = dsa_tag_xmit(iface, pkt);
+	dsa_pkt = dsa_tag_xmit(iface, clone);
 
 	/* Transmit from conduit port */
-	return eth_api_conduit->send(dev_conduit, dsa_pkt);
+	ret = eth_api_conduit->send(dev_conduit, dsa_pkt);
+
+	/* Release the cloned pkt */
+	net_pkt_unref(clone);
+
+	return ret;
 }
 
 int dsa_eth_init(struct net_if *iface)

subsys/net/l2/ethernet/dsa/dsa_port.c

@@ -122,8 +122,33 @@ static const struct device *dsa_port_get_phy(const struct device *dev)
 	return cfg->phy_dev;
 }
 
+#ifdef CONFIG_NET_L2_PTP
+const struct device *dsa_port_get_ptp_clock(const struct device *dev)
+{
+	const struct dsa_port_config *cfg = dev->config;
+
+	return cfg->ptp_clock;
+}
+#endif
+
+enum ethernet_hw_caps dsa_port_get_capabilities(const struct device *dev)
+{
+	uint32_t caps = 0;
+
+#ifdef CONFIG_NET_L2_PTP
+	if (dsa_port_get_ptp_clock(dev) != NULL) {
+		caps |= ETHERNET_PTP;
+	}
+#endif
+	return caps;
+}
+
 const struct ethernet_api dsa_eth_api = {
 	.iface_api.init = dsa_port_iface_init,
 	.get_phy = dsa_port_get_phy,
 	.send = dsa_xmit,
+#ifdef CONFIG_NET_L2_PTP
+	.get_ptp_clock = dsa_port_get_ptp_clock,
+#endif
+	.get_capabilities = dsa_port_get_capabilities,
 };