net: Let the active time stamping layer be selectable.

Add the ETHTOOL_MSG_TS_SET ethtool netlink socket, and add checks in the
ioctl and time stamping paths to respect the currently selected time
stamping layer.

Add a preferred-timestamp devicetree binding to select the preferred
hardware timestamp layer between PHY and MAC. The choice of using
devicetree binding has been made as the PTP precision and quality depends
of external things, like adjustable clock, or the lack of a temperature
compensated crystal or specific features. Even if the preferred timestamp
is a configuration it is hardly related to the design oh the board.

Introduce a NETDEV_CHANGE_HWTSTAMP netdev notifier to let MAC or DSA know
when a hwtstamp change happen. This is useful to manage packet trap in that
case like done by the lan966x driver.

Change the API to select MAC default time stamping instead of the PHY.
Indeed the PHY is closer to the wire therefore theoretically it have less
delay than the MAC timestamping but the reality is different. Due to lower
time stamping clock frequency, latency in the MDIO bus and no PHC hardware
synchronization between different PHY, the PHY PTP is often less precise
than the MAC. The exception is for PHY designed specially for PTP case but
these board are not very widespread. For not breaking the compatibility I
introduce a whitelist to reference all current PHY that support
time stamping and let them keep the old API behavior.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>

Documentation/networking/ethtool-netlink.rst

@@ -2028,6 +2028,18 @@ Kernel response contents:
   ``ETHTOOL_A_TS_LAYER``   u32     available hardware timestamping
   =======================  ======  ===================================
 
+TS_SET
+======
+
+Gets transceiver module parameters.
+
+Request contents:
+
+  =============================  ======  ==============================
+  ``ETHTOOL_A_TS_HEADER``        nested  request header
+  ``ETHTOOL_A_TS_LAYER``         u32     set hardware timestamping
+  =============================  ======  ==============================
+
 Request translation
 ===================
 
@@ -2136,4 +2148,5 @@ are netlink only.
   n/a                                 ``ETHTOOL_MSG_MM_SET``
   n/a                                 ``ETHTOOL_MSG_TS_GET``
   n/a                                 ``ETHTOOL_MSG_TSLIST_GET``
+  n/a                                 ``ETHTOOL_MSG_TS_SET``
   =================================== =====================================

drivers/net/phy/phy_device.c

@@ -34,6 +34,8 @@
 #include <linux/string.h>
 #include <linux/uaccess.h>
 #include <linux/unistd.h>
+#include <linux/of.h>
+#include <uapi/linux/net_tstamp.h>
 
 MODULE_DESCRIPTION("PHY library");
 MODULE_AUTHOR("Andy Fleming");
@@ -1408,6 +1410,83 @@ int phy_sfp_probe(struct phy_device *phydev,
 }
 EXPORT_SYMBOL(phy_sfp_probe);
 
+/**
+ * A whitelist for PHYs selected as default timesetamping.
+ * Its use is to keep compatibility with old PTP API which is selecting
+ * these PHYs as default timestamping.
+ * The new API is selecting the MAC as default timestamping.
+ */
+const char * const phy_timestamping_whitelist[] = {
+	"Broadcom BCM5411",
+	"Broadcom BCM5421",
+	"Broadcom BCM54210E",
+	"Broadcom BCM5461",
+	"Broadcom BCM54612E",
+	"Broadcom BCM5464",
+	"Broadcom BCM5481",
+	"Broadcom BCM54810",
+	"Broadcom BCM54811",
+	"Broadcom BCM5482",
+	"Broadcom BCM50610",
+	"Broadcom BCM50610M",
+	"Broadcom BCM57780",
+	"Broadcom BCM5395",
+	"Broadcom BCM53125",
+	"Broadcom BCM53128",
+	"Broadcom BCM89610",
+	"NatSemi DP83640",
+	"Microchip LAN8841 Gigabit PHY"
+	"Microchip INDY Gigabit Quad PHY",
+	"Microsemi GE VSC856X SyncE",
+	"Microsemi GE VSC8575 SyncE",
+	"Microsemi GE VSC8582 SyncE",
+	"Microsemi GE VSC8584 SyncE",
+	"NXP C45 TJA1103",
+	NULL,
+};
+
+static void of_set_timestamp(struct net_device *netdev, struct phy_device *phydev)
+{
+	struct device_node *node = phydev->mdio.dev.of_node;
+	const struct ethtool_ops *ops = netdev->ethtool_ops;
+	const char *s;
+	enum timestamping_layer ts_layer = 0;
+	int i;
+
+	/* Backward compatibility to old API */
+	for (i = 0; phy_timestamping_whitelist[i] != NULL; i++)
+	{
+		if (!strcmp(phy_timestamping_whitelist[i],
+			    phydev->drv->name)) {
+			if (phy_has_hwtstamp(phydev))
+				ts_layer = SOF_PHY_TIMESTAMPING;
+			else if (ops->get_ts_info)
+				ts_layer = SOF_MAC_TIMESTAMPING;
+			goto out;
+		}
+	}
+
+	if (ops->get_ts_info)
+		ts_layer = SOF_MAC_TIMESTAMPING;
+	else if (phy_has_hwtstamp(phydev))
+		ts_layer = SOF_PHY_TIMESTAMPING;
+
+	if (of_property_read_string(node, "preferred-timestamp", &s))
+		goto out;
+
+	if (!s)
+		goto out;
+
+	if (phy_has_hwtstamp(phydev) && !strcmp(s, "phy"))
+		ts_layer = SOF_PHY_TIMESTAMPING;
+
+	if (ops->get_ts_info && !strcmp(s, "mac"))
+		ts_layer = SOF_MAC_TIMESTAMPING;
+
+out:
+	netdev->selected_timestamping_layer = ts_layer;
+}
+
 /**
  * phy_attach_direct - attach a network device to a given PHY device pointer
  * @dev: network device to attach
@@ -1481,6 +1560,8 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
 
 	phydev->phy_link_change = phy_link_change;
 	if (dev) {
+		of_set_timestamp(dev, phydev);
+
 		phydev->attached_dev = dev;
 		dev->phydev = phydev;
 
@@ -1811,6 +1892,10 @@ void phy_detach(struct phy_device *phydev)
 
 	phy_suspend(phydev);
 	if (dev) {
+		if (dev->ethtool_ops->get_ts_info)
+			dev->selected_timestamping_layer = SOF_MAC_TIMESTAMPING;
+		else
+			dev->selected_timestamping_layer = 0;
 		phydev->attached_dev->phydev = NULL;
 		phydev->attached_dev = NULL;
 	}

include/linux/netdevice.h

@@ -48,6 +48,7 @@
 #include <uapi/linux/if_bonding.h>
 #include <uapi/linux/pkt_cls.h>
 #include <uapi/linux/netdev.h>
+#include <uapi/linux/net_tstamp.h>
 #include <linux/hashtable.h>
 #include <linux/rbtree.h>
 #include <net/net_trackers.h>
@@ -2019,6 +2020,9 @@ enum netdev_ml_priv_type {
  *
  *	@threaded:	napi threaded mode is enabled
  *
+ *	@selected_timestamping_layer:	Tracks whether the MAC or the PHY
+ *					performs packet time stamping.
+ *
  *	@net_notifier_list:	List of per-net netdev notifier block
  *				that follow this device when it is moved
  *				to another network namespace.
@@ -2388,6 +2392,8 @@ struct net_device {
 	unsigned		wol_enabled:1;
 	unsigned		threaded:1;
 
+	enum timestamping_layer selected_timestamping_layer;
+
 	struct list_head	net_notifier_list;
 
 #if IS_ENABLED(CONFIG_MACSEC)
@@ -2879,6 +2885,7 @@ enum netdev_cmd {
 	NETDEV_OFFLOAD_XSTATS_REPORT_DELTA,
 	NETDEV_XDP_FEAT_CHANGE,
 	NETDEV_PRE_CHANGE_HWTSTAMP,
+	NETDEV_CHANGE_HWTSTAMP,
 };
 const char *netdev_cmd_to_name(enum netdev_cmd cmd);
 
@@ -2934,6 +2941,11 @@ struct netdev_notifier_hwtstamp_info {
 	struct kernel_hwtstamp_config *config;
 };
 
+struct netdev_notifier_hwtstamp_layer {
+	struct netdev_notifier_info info; /* must be first */
+	enum timestamping_layer ts_layer;
+};
+
 enum netdev_offload_xstats_type {
 	NETDEV_OFFLOAD_XSTATS_TYPE_L3 = 1,
 };

include/uapi/linux/ethtool_netlink.h

@@ -41,6 +41,7 @@ enum {
 	ETHTOOL_MSG_TSINFO_GET,
 	ETHTOOL_MSG_TSLIST_GET,
 	ETHTOOL_MSG_TS_GET,
+	ETHTOOL_MSG_TS_SET,
 	ETHTOOL_MSG_CABLE_TEST_ACT,
 	ETHTOOL_MSG_CABLE_TEST_TDR_ACT,
 	ETHTOOL_MSG_TUNNEL_INFO_GET,
@@ -96,6 +97,7 @@ enum {
 	ETHTOOL_MSG_TSINFO_GET_REPLY,
 	ETHTOOL_MSG_TSLIST_GET_REPLY,
 	ETHTOOL_MSG_TS_GET_REPLY,
+	ETHTOOL_MSG_TS_NTF,
 	ETHTOOL_MSG_CABLE_TEST_NTF,
 	ETHTOOL_MSG_CABLE_TEST_TDR_NTF,
 	ETHTOOL_MSG_TUNNEL_INFO_GET_REPLY,

net/core/dev.c

@@ -1612,7 +1612,7 @@ const char *netdev_cmd_to_name(enum netdev_cmd cmd)
 	N(SVLAN_FILTER_PUSH_INFO) N(SVLAN_FILTER_DROP_INFO)
 	N(PRE_CHANGEADDR) N(OFFLOAD_XSTATS_ENABLE) N(OFFLOAD_XSTATS_DISABLE)
 	N(OFFLOAD_XSTATS_REPORT_USED) N(OFFLOAD_XSTATS_REPORT_DELTA)
-	N(XDP_FEAT_CHANGE) N(PRE_CHANGE_HWTSTAMP)
+	N(XDP_FEAT_CHANGE) N(PRE_CHANGE_HWTSTAMP) N(CHANGE_HWTSTAMP)
 	}
 #undef N
 	return "UNKNOWN_NETDEV_EVENT";

net/core/dev_ioctl.c

@@ -7,6 +7,7 @@
 #include <linux/net_tstamp.h>
 #include <linux/wireless.h>
 #include <linux/if_bridge.h>
+#include <linux/phy.h>
 #include <net/dsa.h>
 #include <net/wext.h>
 
@@ -252,9 +253,60 @@ static int dev_eth_ioctl(struct net_device *dev,
 	return ops->ndo_eth_ioctl(dev, ifr, cmd);
 }
 
+static int __dev_eth_ioctl(struct net_device *dev,
+			   struct ifreq *ifr, unsigned int cmd)
+{
+	struct netdev_notifier_hwtstamp_layer hwtstamp_layer = {
+		.info.dev = dev,
+		.ts_layer = dev->selected_timestamping_layer,
+	};
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct netlink_ext_ack extack = {};
+	int err;
+
+	if (!netif_device_present(dev))
+		return -ENODEV;
+
+	switch (dev->selected_timestamping_layer) {
+	case SOF_MAC_TIMESTAMPING:
+		if (ops->ndo_do_ioctl == phy_do_ioctl) {
+			/* Some drivers set .ndo_do_ioctl to phy_do_ioctl. */
+			return -EOPNOTSUPP;
+		} else {
+			err = dev_eth_ioctl(dev, ifr, cmd);
+			if (err)
+				goto out;
+		}
+		break;
+
+	case SOF_PHY_TIMESTAMPING:
+		if (phy_has_hwtstamp(dev->phydev)) {
+			err = phy_mii_ioctl(dev->phydev, ifr, cmd);
+			if (err)
+				goto out;
+		} else {
+			return -ENODEV;
+		}
+		break;
+	}
+
+	hwtstamp_layer.info.extack = &extack;
+
+	err = call_netdevice_notifiers_info(NETDEV_CHANGE_HWTSTAMP,
+					    &hwtstamp_layer.info);
+	err = notifier_to_errno(err);
+	if (err) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
+	}
+
+out:
+	return err;
+}
+
 static int dev_get_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 {
-	return dev_eth_ioctl(dev, ifr, SIOCGHWTSTAMP);
+	return __dev_eth_ioctl(dev, ifr, SIOCGHWTSTAMP);
 }
 
 static int dev_set_hwtstamp(struct net_device *dev, struct ifreq *ifr)
@@ -288,7 +340,7 @@ static int dev_set_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 		return err;
 	}
 
-	return dev_eth_ioctl(dev, ifr, SIOCSHWTSTAMP);
+	return __dev_eth_ioctl(dev, ifr, SIOCSHWTSTAMP);
 }
 
 static int dev_siocbond(struct net_device *dev,

net/core/timestamping.c

@@ -28,6 +28,9 @@ void skb_clone_tx_timestamp(struct sk_buff *skb)
 	if (!skb->sk)
 		return;
 
+	if (skb->dev->selected_timestamping_layer != SOF_PHY_TIMESTAMPING)
+		return;
+
 	type = classify(skb);
 	if (type == PTP_CLASS_NONE)
 		return;
@@ -50,6 +53,9 @@ bool skb_defer_rx_timestamp(struct sk_buff *skb)
 	if (!skb->dev || !skb->dev->phydev || !skb->dev->phydev->mii_ts)
 		return false;
 
+	if (skb->dev->selected_timestamping_layer != SOF_PHY_TIMESTAMPING)
+		return false;
+
 	if (skb_headroom(skb) < ETH_HLEN)
 		return false;
 

net/ethtool/common.c

@@ -637,10 +637,17 @@ int __ethtool_get_ts_info(struct net_device *dev, struct ethtool_ts_info *info)
 	memset(info, 0, sizeof(*info));
 	info->cmd = ETHTOOL_GET_TS_INFO;
 
-	if (phy_has_tsinfo(phydev))
-		return phy_ts_info(phydev, info);
-	if (ops->get_ts_info)
-		return ops->get_ts_info(dev, info);
+	switch (dev->selected_timestamping_layer) {
+	case SOF_MAC_TIMESTAMPING:
+		if (ops->get_ts_info)
+			return ops->get_ts_info(dev, info);
+		break;
+
+	case SOF_PHY_TIMESTAMPING:
+		if (phy_has_tsinfo(phydev))
+			return phy_ts_info(phydev, info);
+		return -ENODEV;
+	}
 
 	info->so_timestamping = SOF_TIMESTAMPING_RX_SOFTWARE |
 				SOF_TIMESTAMPING_SOFTWARE;

net/ethtool/netlink.c

@@ -294,6 +294,7 @@ ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
 	[ETHTOOL_MSG_FEC_SET]		= &ethnl_fec_request_ops,
 	[ETHTOOL_MSG_TSINFO_GET]	= &ethnl_tsinfo_request_ops,
 	[ETHTOOL_MSG_TS_GET]		= &ethnl_ts_request_ops,
+	[ETHTOOL_MSG_TS_SET]		= &ethnl_ts_request_ops,
 	[ETHTOOL_MSG_TSLIST_GET]	= &ethnl_tslist_request_ops,
 	[ETHTOOL_MSG_MODULE_EEPROM_GET]	= &ethnl_module_eeprom_request_ops,
 	[ETHTOOL_MSG_STATS_GET]		= &ethnl_stats_request_ops,
@@ -671,6 +672,7 @@ ethnl_default_notify_ops[ETHTOOL_MSG_KERNEL_MAX + 1] = {
 	[ETHTOOL_MSG_MODULE_NTF]	= &ethnl_module_request_ops,
 	[ETHTOOL_MSG_PLCA_NTF]		= &ethnl_plca_cfg_request_ops,
 	[ETHTOOL_MSG_MM_NTF]		= &ethnl_mm_request_ops,
+	[ETHTOOL_MSG_TS_NTF]		= &ethnl_ts_request_ops,
 };
 
 /* default notification handler */
@@ -766,6 +768,7 @@ static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_MODULE_NTF]	= ethnl_default_notify,
 	[ETHTOOL_MSG_PLCA_NTF]		= ethnl_default_notify,
 	[ETHTOOL_MSG_MM_NTF]		= ethnl_default_notify,
+	[ETHTOOL_MSG_TS_NTF]		= ethnl_default_notify,
 };
 
 void ethtool_notify(struct net_device *dev, unsigned int cmd, const void *data)
@@ -1031,6 +1034,13 @@ static const struct genl_ops ethtool_genl_ops[] = {
 		.policy = ethnl_ts_get_policy,
 		.maxattr = ARRAY_SIZE(ethnl_ts_get_policy) - 1,
 	},
+	{
+		.cmd	= ETHTOOL_MSG_TS_SET,
+		.flags	= GENL_UNS_ADMIN_PERM,
+		.doit	= ethnl_default_set_doit,
+		.policy = ethnl_ts_set_policy,
+		.maxattr = ARRAY_SIZE(ethnl_ts_set_policy) - 1,
+	},
 	{
 		.cmd	= ETHTOOL_MSG_CABLE_TEST_ACT,
 		.flags	= GENL_UNS_ADMIN_PERM,

net/ethtool/netlink.h

@@ -426,6 +426,7 @@ extern const struct nla_policy ethnl_eee_get_policy[ETHTOOL_A_EEE_HEADER + 1];
 extern const struct nla_policy ethnl_eee_set_policy[ETHTOOL_A_EEE_TX_LPI_TIMER + 1];
 extern const struct nla_policy ethnl_tsinfo_get_policy[ETHTOOL_A_TSINFO_HEADER + 1];
 extern const struct nla_policy ethnl_ts_get_policy[ETHTOOL_A_TS_HEADER + 1];
+extern const struct nla_policy ethnl_ts_set_policy[ETHTOOL_A_TS_LAYER + 1];
 extern const struct nla_policy ethnl_cable_test_act_policy[ETHTOOL_A_CABLE_TEST_HEADER + 1];
 extern const struct nla_policy ethnl_cable_test_tdr_act_policy[ETHTOOL_A_CABLE_TEST_TDR_CFG + 1];
 extern const struct nla_policy ethnl_tunnel_info_get_policy[ETHTOOL_A_TUNNEL_INFO_HEADER + 1];