net: Add the possibility to support a selected hwtstamp in netdevice

Introduce the description of a hwtstamp provider, mainly defined with a
the hwtstamp source and the phydev pointer.

Add a hwtstamp provider description within the netdev structure to
allow saving the hwtstamp we want to use. This prepares for future
support of an ethtool netlink command to select the desired hwtstamp
provider. By default, the old API that does not support hwtstamp
selectability is used, meaning the hwtstamp provider pointer is unset.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 86 insertions, 7 deletions

diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 1f09930fca26..087a57b7e4fa 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -6,6 +6,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/net_tstamp.h>
 #include <linux/phylib_stubs.h>
+#include <linux/ptp_clock_kernel.h>
 #include <linux/wireless.h>
 #include <linux/if_bridge.h>
 #include <net/dsa_stubs.h>
@@ -269,6 +270,21 @@ static int dev_eth_ioctl(struct net_device *dev,
 int dev_get_hwtstamp_phylib(struct net_device *dev,
 			    struct kernel_hwtstamp_config *cfg)
 {
+	struct hwtstamp_provider *hwprov;
+
+	hwprov = rtnl_dereference(dev->hwprov);
+	if (hwprov) {
+		cfg->qualifier = hwprov->desc.qualifier;
+		if (hwprov->source == HWTSTAMP_SOURCE_PHYLIB &&
+		    hwprov->phydev)
+			return phy_hwtstamp_get(hwprov->phydev, cfg);
+
+		if (hwprov->source == HWTSTAMP_SOURCE_NETDEV)
+			return dev->netdev_ops->ndo_hwtstamp_get(dev, cfg);
+
+		return -EOPNOTSUPP;
+	}
+
 	if (phy_is_default_hwtstamp(dev->phydev))
 		return phy_hwtstamp_get(dev->phydev, cfg);
 
@@ -324,11 +340,32 @@ int dev_set_hwtstamp_phylib(struct net_device *dev,
 			    struct netlink_ext_ack *extack)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
-	bool phy_ts = phy_is_default_hwtstamp(dev->phydev);
 	struct kernel_hwtstamp_config old_cfg = {};
+	struct hwtstamp_provider *hwprov;
+	struct phy_device *phydev;
 	bool changed = false;
+	bool phy_ts;
 	int err;
 
+	hwprov = rtnl_dereference(dev->hwprov);
+	if (hwprov) {
+		if (hwprov->source == HWTSTAMP_SOURCE_PHYLIB &&
+		    hwprov->phydev) {
+			phy_ts = true;
+			phydev = hwprov->phydev;
+		} else if (hwprov->source == HWTSTAMP_SOURCE_NETDEV) {
+			phy_ts = false;
+		} else {
+			return -EOPNOTSUPP;
+		}
+
+		cfg->qualifier = hwprov->desc.qualifier;
+	} else {
+		phy_ts = phy_is_default_hwtstamp(dev->phydev);
+		if (phy_ts)
+			phydev = dev->phydev;
+	}
+
 	cfg->source = phy_ts ? HWTSTAMP_SOURCE_PHYLIB : HWTSTAMP_SOURCE_NETDEV;
 
 	if (phy_ts && dev->see_all_hwtstamp_requests) {
@@ -350,7 +387,7 @@ int dev_set_hwtstamp_phylib(struct net_device *dev,
 		changed = kernel_hwtstamp_config_changed(&old_cfg, cfg);
 
 	if (phy_ts) {
-		err = phy_hwtstamp_set(dev->phydev, cfg, extack);
+		err = phy_hwtstamp_set(phydev, cfg, extack);
 		if (err) {
 			if (changed)
 				ops->ndo_hwtstamp_set(dev, &old_cfg, NULL);
diff --git a/net/core/timestamping.c b/net/core/timestamping.c
index 3717fb152ecc..a50a7ef49ae8 100644
--- a/net/core/timestamping.c
+++ b/net/core/timestamping.c
@@ -9,6 +9,7 @@
 #include <linux/ptp_classify.h>
 #include <linux/skbuff.h>
 #include <linux/export.h>
+#include <linux/ptp_clock_kernel.h>
 
 static unsigned int classify(const struct sk_buff *skb)
 {
@@ -21,19 +22,39 @@ static unsigned int classify(const struct sk_buff *skb)
 
 void skb_clone_tx_timestamp(struct sk_buff *skb)
 {
+	struct hwtstamp_provider *hwprov;
 	struct mii_timestamper *mii_ts;
+	struct phy_device *phydev;
 	struct sk_buff *clone;
 	unsigned int type;
 
-	if (!skb->sk || !skb->dev ||
-	    !phy_is_default_hwtstamp(skb->dev->phydev))
+	if (!skb->sk || !skb->dev)
 		return;
 
+	rcu_read_lock();
+	hwprov = rcu_dereference(skb->dev->hwprov);
+	if (hwprov) {
+		if (hwprov->source != HWTSTAMP_SOURCE_PHYLIB ||
+		    !hwprov->phydev) {
+			rcu_read_unlock();
+			return;
+		}
+
+		phydev = hwprov->phydev;
+	} else {
+		phydev = skb->dev->phydev;
+		if (!phy_is_default_hwtstamp(phydev)) {
+			rcu_read_unlock();
+			return;
+		}
+	}
+	rcu_read_unlock();
+
 	type = classify(skb);
 	if (type == PTP_CLASS_NONE)
 		return;
 
-	mii_ts = skb->dev->phydev->mii_ts;
+	mii_ts = phydev->mii_ts;
 	if (likely(mii_ts->txtstamp)) {
 		clone = skb_clone_sk(skb);
 		if (!clone)
@@ -45,12 +66,33 @@ EXPORT_SYMBOL_GPL(skb_clone_tx_timestamp);
 
 bool skb_defer_rx_timestamp(struct sk_buff *skb)
 {
+	struct hwtstamp_provider *hwprov;
 	struct mii_timestamper *mii_ts;
+	struct phy_device *phydev;
 	unsigned int type;
 
-	if (!skb->dev || !phy_is_default_hwtstamp(skb->dev->phydev))
+	if (!skb->dev)
 		return false;
 
+	rcu_read_lock();
+	hwprov = rcu_dereference(skb->dev->hwprov);
+	if (hwprov) {
+		if (hwprov->source != HWTSTAMP_SOURCE_PHYLIB ||
+		    !hwprov->phydev) {
+			rcu_read_unlock();
+			return false;
+		}
+
+		phydev = hwprov->phydev;
+	} else {
+		phydev = skb->dev->phydev;
+		if (!phy_is_default_hwtstamp(phydev)) {
+			rcu_read_unlock();
+			return false;
+		}
+	}
+	rcu_read_unlock();
+
 	if (skb_headroom(skb) < ETH_HLEN)
 		return false;
 
@@ -63,7 +105,7 @@ bool skb_defer_rx_timestamp(struct sk_buff *skb)
 	if (type == PTP_CLASS_NONE)
 		return false;
 
-	mii_ts = skb->dev->phydev->mii_ts;
+	mii_ts = phydev->mii_ts;
 	if (likely(mii_ts->rxtstamp))
 		return mii_ts->rxtstamp(mii_ts, skb, type);