net: Introduce a new MII time stamping interface.

Currently the stack supports time stamping in PHY devices. However,
there are newer, non-PHY devices that can snoop an MII bus and provide
time stamps. In order to support such devices, this patch introduces
a new interface to be used by both PHY and non-PHY devices.

In addition, the one and only user of the old PHY time stamping API is
converted to the new interface.

Signed-off-by: Richard Cochran <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/dp83640.c

···
 	struct list_head list;
 	struct dp83640_clock *clock;
 	struct phy_device *phydev;
+	struct mii_timestamper mii_ts;
 	struct delayed_work ts_work;
 	int hwts_tx_en;
 	int hwts_rx_en;
···
 	}
 }
 
-static int dp83640_hwtstamp(struct phy_device *phydev, struct ifreq *ifr)
+static int dp83640_hwtstamp(struct mii_timestamper *mii_ts, struct ifreq *ifr)
 {
-	struct dp83640_private *dp83640 = phydev->priv;
+	struct dp83640_private *dp83640 =
+		container_of(mii_ts, struct dp83640_private, mii_ts);
 	struct hwtstamp_config cfg;
 	u16 txcfg0, rxcfg0;
 
···
 
 	mutex_lock(&dp83640->clock->extreg_lock);
 
-	ext_write(0, phydev, PAGE5, PTP_TXCFG0, txcfg0);
-	ext_write(0, phydev, PAGE5, PTP_RXCFG0, rxcfg0);
+	ext_write(0, dp83640->phydev, PAGE5, PTP_TXCFG0, txcfg0);
+	ext_write(0, dp83640->phydev, PAGE5, PTP_RXCFG0, rxcfg0);
 
 	mutex_unlock(&dp83640->clock->extreg_lock);
 
···
 		schedule_delayed_work(&dp83640->ts_work, SKB_TIMESTAMP_TIMEOUT);
 }
 
-static bool dp83640_rxtstamp(struct phy_device *phydev,
+static bool dp83640_rxtstamp(struct mii_timestamper *mii_ts,
 			     struct sk_buff *skb, int type)
 {
-	struct dp83640_private *dp83640 = phydev->priv;
+	struct dp83640_private *dp83640 =
+		container_of(mii_ts, struct dp83640_private, mii_ts);
 	struct dp83640_skb_info *skb_info = (struct dp83640_skb_info *)skb->cb;
 	struct list_head *this, *next;
 	struct rxts *rxts;
···
 	return true;
 }
 
-static void dp83640_txtstamp(struct phy_device *phydev,
+static void dp83640_txtstamp(struct mii_timestamper *mii_ts,
 			     struct sk_buff *skb, int type)
 {
 	struct dp83640_skb_info *skb_info = (struct dp83640_skb_info *)skb->cb;
-	struct dp83640_private *dp83640 = phydev->priv;
+	struct dp83640_private *dp83640 =
+		container_of(mii_ts, struct dp83640_private, mii_ts);
 
 	switch (dp83640->hwts_tx_en) {
 
···
 	}
 }
 
-static int dp83640_ts_info(struct phy_device *dev, struct ethtool_ts_info *info)
+static int dp83640_ts_info(struct mii_timestamper *mii_ts,
+			   struct ethtool_ts_info *info)
 {
-	struct dp83640_private *dp83640 = dev->priv;
+	struct dp83640_private *dp83640 =
+		container_of(mii_ts, struct dp83640_private, mii_ts);
 
 	info->so_timestamping =
 		SOF_TIMESTAMPING_TX_HARDWARE |
···
 		goto no_memory;
 
 	dp83640->phydev = phydev;
-	INIT_DELAYED_WORK(&dp83640->ts_work, rx_timestamp_work);
+	dp83640->mii_ts.rxtstamp = dp83640_rxtstamp;
+	dp83640->mii_ts.txtstamp = dp83640_txtstamp;
+	dp83640->mii_ts.hwtstamp = dp83640_hwtstamp;
+	dp83640->mii_ts.ts_info  = dp83640_ts_info;
 
+	INIT_DELAYED_WORK(&dp83640->ts_work, rx_timestamp_work);
 	INIT_LIST_HEAD(&dp83640->rxts);
 	INIT_LIST_HEAD(&dp83640->rxpool);
 	for (i = 0; i < MAX_RXTS; i++)
 		list_add(&dp83640->rx_pool_data[i].list, &dp83640->rxpool);
 
+	phydev->mii_ts = &dp83640->mii_ts;
 	phydev->priv = dp83640;
 
 	spin_lock_init(&dp83640->rx_lock);
···
 	if (phydev->mdio.addr == BROADCAST_ADDR)
 		return;
 
+	phydev->mii_ts = NULL;
+
 	enable_status_frames(phydev, false);
 	cancel_delayed_work_sync(&dp83640->ts_work);
 
···
 	.config_init	= dp83640_config_init,
 	.ack_interrupt  = dp83640_ack_interrupt,
 	.config_intr    = dp83640_config_intr,
-	.ts_info	= dp83640_ts_info,
-	.hwtstamp	= dp83640_hwtstamp,
-	.rxtstamp	= dp83640_rxtstamp,
-	.txtstamp	= dp83640_txtstamp,
 };
 
 static int __init dp83640_init(void)

drivers/net/phy/phy.c

···
 		return 0;
 
 	case SIOCSHWTSTAMP:
-		if (phydev->drv && phydev->drv->hwtstamp)
-			return phydev->drv->hwtstamp(phydev, ifr);
+		if (phydev->mii_ts && phydev->mii_ts->hwtstamp)
+			return phydev->mii_ts->hwtstamp(phydev->mii_ts, ifr);
 		/* fall through */
 
 	default:

drivers/net/phy/phy_device.c

···
 			netif_carrier_off(netdev);
 	}
 	phydev->adjust_link(netdev);
+	if (phydev->mii_ts && phydev->mii_ts->link_state)
+		phydev->mii_ts->link_state(phydev->mii_ts, phydev);
 }
 
 /**

include/linux/mii_timestamper.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Support for generic time stamping devices on MII buses.
+ * Copyright (C) 2018 Richard Cochran <[e-mail]>
+ */
+#ifndef _LINUX_MII_TIMESTAMPER_H
+#define _LINUX_MII_TIMESTAMPER_H
+
+#include <linux/device.h>
+#include <linux/ethtool.h>
+#include <linux/skbuff.h>
+
+struct phy_device;
+
+/**
+ * struct mii_timestamper - Callback interface to MII time stamping devices.
+ *
+ * @rxtstamp:	Requests a Rx timestamp for 'skb'.  If the skb is accepted,
+ *		the MII time stamping device promises to deliver it using
+ *		netif_rx() as soon as a timestamp becomes available. One of
+ *		the PTP_CLASS_ values is passed in 'type'.  The function
+ *		must return true if the skb is accepted for delivery.
+ *
+ * @txtstamp:	Requests a Tx timestamp for 'skb'.  The MII time stamping
+ *		device promises to deliver it using skb_complete_tx_timestamp()
+ *		as soon as a timestamp becomes available. One of the PTP_CLASS_
+ *		values is passed in 'type'.
+ *
+ * @hwtstamp:	Handles SIOCSHWTSTAMP ioctl for hardware time stamping.
+ *
+ * @link_state: Allows the device to respond to changes in the link
+ *		state.  The caller invokes this function while holding
+ *		the phy_device mutex.
+ *
+ * @ts_info:	Handles ethtool queries for hardware time stamping.
+ *
+ * Drivers for PHY time stamping devices should embed their
+ * mii_timestamper within a private structure, obtaining a reference
+ * to it using container_of().
+ */
+struct mii_timestamper {
+	bool (*rxtstamp)(struct mii_timestamper *mii_ts,
+			 struct sk_buff *skb, int type);
+
+	void (*txtstamp)(struct mii_timestamper *mii_ts,
+			 struct sk_buff *skb, int type);
+
+	int  (*hwtstamp)(struct mii_timestamper *mii_ts,
+			 struct ifreq *ifreq);
+
+	void (*link_state)(struct mii_timestamper *mii_ts,
+			   struct phy_device *phydev);
+
+	int  (*ts_info)(struct mii_timestamper *mii_ts,
+			struct ethtool_ts_info *ts_info);
+};
+
+#endif

include/linux/phy.h

···
 #include <linux/linkmode.h>
 #include <linux/mdio.h>
 #include <linux/mii.h>
+#include <linux/mii_timestamper.h>
 #include <linux/module.h>
 #include <linux/timer.h>
 #include <linux/workqueue.h>
···
 	struct sfp_bus *sfp_bus;
 	struct phylink *phylink;
 	struct net_device *attached_dev;
+	struct mii_timestamper *mii_ts;
 
 	u8 mdix;
 	u8 mdix_ctrl;
···
 	 * phy_id_mask.
 	 */
 	int (*match_phy_device)(struct phy_device *phydev);
-
-	/* Handles ethtool queries for hardware time stamping. */
-	int (*ts_info)(struct phy_device *phydev, struct ethtool_ts_info *ti);
-
-	/* Handles SIOCSHWTSTAMP ioctl for hardware time stamping. */
-	int  (*hwtstamp)(struct phy_device *phydev, struct ifreq *ifr);
-
-	/*
-	 * Requests a Rx timestamp for 'skb'. If the skb is accepted,
-	 * the phy driver promises to deliver it using netif_rx() as
-	 * soon as a timestamp becomes available. One of the
-	 * PTP_CLASS_ values is passed in 'type'. The function must
-	 * return true if the skb is accepted for delivery.
-	 */
-	bool (*rxtstamp)(struct phy_device *dev, struct sk_buff *skb, int type);
-
-	/*
-	 * Requests a Tx timestamp for 'skb'. The phy driver promises
-	 * to deliver it using skb_complete_tx_timestamp() as soon as a
-	 * timestamp becomes available. One of the PTP_CLASS_ values
-	 * is passed in 'type'.
-	 */
-	void (*txtstamp)(struct phy_device *dev, struct sk_buff *skb, int type);
 
 	/* Some devices (e.g. qnap TS-119P II) require PHY register changes to
 	 * enable Wake on LAN, so set_wol is provided to be called in the
···
  */
 static inline bool phy_has_hwtstamp(struct phy_device *phydev)
 {
-	return phydev && phydev->drv && phydev->drv->hwtstamp;
+	return phydev && phydev->mii_ts && phydev->mii_ts->hwtstamp;
 }
 
 /**
···
  */
 static inline bool phy_has_rxtstamp(struct phy_device *phydev)
 {
-	return phydev && phydev->drv && phydev->drv->rxtstamp;
+	return phydev && phydev->mii_ts && phydev->mii_ts->rxtstamp;
 }
 
 /**
···
  */
 static inline bool phy_has_tsinfo(struct phy_device *phydev)
 {
-	return phydev && phydev->drv && phydev->drv->ts_info;
+	return phydev && phydev->mii_ts && phydev->mii_ts->ts_info;
 }
 
 /**
···
  */
 static inline bool phy_has_txtstamp(struct phy_device *phydev)
 {
-	return phydev && phydev->drv && phydev->drv->txtstamp;
+	return phydev && phydev->mii_ts && phydev->mii_ts->txtstamp;
 }
 
 static inline int phy_hwtstamp(struct phy_device *phydev, struct ifreq *ifr)
 {
-	return phydev->drv->hwtstamp(phydev, ifr);
+	return phydev->mii_ts->hwtstamp(phydev->mii_ts, ifr);
 }
 
 static inline bool phy_rxtstamp(struct phy_device *phydev, struct sk_buff *skb,
 				int type)
 {
-	return phydev->drv->rxtstamp(phydev, skb, type);
+	return phydev->mii_ts->rxtstamp(phydev->mii_ts, skb, type);
 }
 
 static inline int phy_ts_info(struct phy_device *phydev,
 			      struct ethtool_ts_info *tsinfo)
 {
-	return phydev->drv->ts_info(phydev, tsinfo);
+	return phydev->mii_ts->ts_info(phydev->mii_ts, tsinfo);
 }
 
 static inline void phy_txtstamp(struct phy_device *phydev, struct sk_buff *skb,
 				int type)
 {
-	phydev->drv->txtstamp(phydev, skb, type);
+	phydev->mii_ts->txtstamp(phydev->mii_ts, skb, type);
 }
 
 /**

net/core/timestamping.c

···
 static unsigned int classify(const struct sk_buff *skb)
 {
 	if (likely(skb->dev && skb->dev->phydev &&
-		   skb->dev->phydev->drv))
+		   skb->dev->phydev->mii_ts))
 		return ptp_classify_raw(skb);
 	else
 		return PTP_CLASS_NONE;
···
 
 void skb_clone_tx_timestamp(struct sk_buff *skb)
 {
-	struct phy_device *phydev;
+	struct mii_timestamper *mii_ts;
 	struct sk_buff *clone;
 	unsigned int type;
 
···
 	if (type == PTP_CLASS_NONE)
 		return;
 
-	phydev = skb->dev->phydev;
-	if (likely(phydev->drv->txtstamp)) {
+	mii_ts = skb->dev->phydev->mii_ts;
+	if (likely(mii_ts->txtstamp)) {
 		clone = skb_clone_sk(skb);
 		if (!clone)
 			return;
-		phydev->drv->txtstamp(phydev, clone, type);
+		mii_ts->txtstamp(mii_ts, clone, type);
 	}
 }
 EXPORT_SYMBOL_GPL(skb_clone_tx_timestamp);
 
 bool skb_defer_rx_timestamp(struct sk_buff *skb)
 {
-	struct phy_device *phydev;
+	struct mii_timestamper *mii_ts;
 	unsigned int type;
 
-	if (!skb->dev || !skb->dev->phydev || !skb->dev->phydev->drv)
+	if (!skb->dev || !skb->dev->phydev || !skb->dev->phydev->mii_ts)
 		return false;
 
 	if (skb_headroom(skb) < ETH_HLEN)
···
 	if (type == PTP_CLASS_NONE)
 		return false;
 
-	phydev = skb->dev->phydev;
-	if (likely(phydev->drv->rxtstamp))
-		return phydev->drv->rxtstamp(phydev, skb, type);
+	mii_ts = skb->dev->phydev->mii_ts;
+	if (likely(mii_ts->rxtstamp))
+		return mii_ts->rxtstamp(mii_ts, skb, type);
 
 	return false;
 }