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From:   Horatiu Vultur <horatiu.vultur@microchip.com>
To:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <andrew@lunn.ch>, <hkallweit1@gmail.com>, <linux@armlinux.org.uk>,
        <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <richardcochran@gmail.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>
Subject: [PATCH net-next v3] net: micrel: Change to receive timestamp in the frame for lan8841
Date:   Thu, 15 Jun 2023 11:47:40 +0200
Message-ID: <20230615094740.627051-1-horatiu.vultur@microchip.com>
MIME-Version: 1.0
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Precedence: bulk

Currently for each timestamp frame, the SW needs to go and read the
received timestamp over the MDIO bus. But the HW has the capability
to store the received nanoseconds part and the least significant two
bits of the seconds in the reserved field of the PTP header. In this
way we could save few MDIO transactions (actually a little more
transactions because the access to the PTP registers are indirect)
for each received frame.

Instead of reading the rest of seconds part of the timestamp of the
frame using MDIO transactions schedule PTP worker thread to read the
seconds part every 500ms and then for each of the received frames use
this information. Because if for example running with 512 frames per
second, there is no point to read 512 times the second part.

Doing all these changes will give a great CPU usage performance.
Running ptp4l with logSyncInterval of -9 will give a ~60% CPU
improvement.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>

---
v2->v3:
- create back a single patch instead of patch series because the
  optimization will modify mostly the first patch.
- use ptp worker thread to read the second part instead of allocating a
  new work.

v1->v2:
- create a patch series instead of single patch.
- add optimization for reading the second part of the received timestamp,
  read the second twice per second instead of for each frame.
---
 drivers/net/phy/micrel.c | 250 ++++++++++++++++++++++++---------------
 1 file changed, 154 insertions(+), 96 deletions(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 0ff4fd9f1a183..83ef4988bc87d 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -254,6 +254,9 @@
 #define PS_TO_REG				200
 #define FIFO_SIZE				8
 
+/* Delay used to get the second part from the LTC */
+#define LAN8841_GET_SEC_LTC_DELAY		(500 * NSEC_PER_MSEC)
+
 struct kszphy_hw_stat {
 	const char *string;
 	u8 reg;
@@ -321,6 +324,10 @@ struct kszphy_ptp_priv {
 	/* Lock for ptp_clock */
 	struct mutex ptp_lock;
 	struct ptp_pin_desc *pin_config;
+
+	s64 seconds;
+	/* Lock for accessing seconds */
+	spinlock_t seconds_lock;
 };
 
 struct kszphy_priv {
@@ -3502,6 +3509,9 @@ static int lan8814_probe(struct phy_device *phydev)
 #define LAN8841_PTP_CMD_CTL_PTP_RESET		BIT(0)
 #define LAN8841_PTP_RX_PARSE_CONFIG		368
 #define LAN8841_PTP_TX_PARSE_CONFIG		432
+#define LAN8841_PTP_RX_MODE			381
+#define LAN8841_PTP_INSERT_TS_EN		BIT(0)
+#define LAN8841_PTP_INSERT_TS_32BIT		BIT(1)
 
 static int lan8841_config_init(struct phy_device *phydev)
 {
@@ -3650,68 +3660,18 @@ static void lan8841_ptp_process_tx_ts(struct kszphy_ptp_priv *ptp_priv)
 		lan8814_match_tx_skb(ptp_priv, sec, nsec, seq);
 }
 
-#define LAN8841_PTP_RX_INGRESS_SEC_LO			389
-#define LAN8841_PTP_RX_INGRESS_SEC_HI			388
-#define LAN8841_PTP_RX_INGRESS_NS_LO			387
-#define LAN8841_PTP_RX_INGRESS_NS_HI			386
-#define LAN8841_PTP_RX_INGRESS_NSEC_HI_VALID		BIT(15)
-#define LAN8841_PTP_RX_MSG_HEADER2			391
-
-static struct lan8814_ptp_rx_ts *lan8841_ptp_get_rx_ts(struct kszphy_ptp_priv *ptp_priv)
-{
-	struct phy_device *phydev = ptp_priv->phydev;
-	struct lan8814_ptp_rx_ts *rx_ts;
-	u32 sec, nsec;
-	u16 seq;
-
-	nsec = phy_read_mmd(phydev, 2, LAN8841_PTP_RX_INGRESS_NS_HI);
-	if (!(nsec & LAN8841_PTP_RX_INGRESS_NSEC_HI_VALID))
-		return NULL;
-
-	nsec = ((nsec & 0x3fff) << 16);
-	nsec = nsec | phy_read_mmd(phydev, 2, LAN8841_PTP_RX_INGRESS_NS_LO);
-
-	sec = phy_read_mmd(phydev, 2, LAN8841_PTP_RX_INGRESS_SEC_HI);
-	sec = sec << 16;
-	sec = sec | phy_read_mmd(phydev, 2, LAN8841_PTP_RX_INGRESS_SEC_LO);
-
-	seq = phy_read_mmd(phydev, 2, LAN8841_PTP_RX_MSG_HEADER2);
-
-	rx_ts = kzalloc(sizeof(*rx_ts), GFP_KERNEL);
-	if (!rx_ts)
-		return NULL;
-
-	rx_ts->seconds = sec;
-	rx_ts->nsec = nsec;
-	rx_ts->seq_id = seq;
-
-	return rx_ts;
-}
-
-static void lan8841_ptp_process_rx_ts(struct kszphy_ptp_priv *ptp_priv)
-{
-	struct lan8814_ptp_rx_ts *rx_ts;
-
-	while ((rx_ts = lan8841_ptp_get_rx_ts(ptp_priv)) != NULL)
-		lan8814_match_rx_ts(ptp_priv, rx_ts);
-}
-
 #define LAN8841_PTP_INT_STS			259
 #define LAN8841_PTP_INT_STS_PTP_TX_TS_OVRFL_INT	BIT(13)
 #define LAN8841_PTP_INT_STS_PTP_TX_TS_INT	BIT(12)
-#define LAN8841_PTP_INT_STS_PTP_RX_TS_OVRFL_INT	BIT(9)
-#define LAN8841_PTP_INT_STS_PTP_RX_TS_INT	BIT(8)
 #define LAN8841_PTP_INT_STS_PTP_GPIO_CAP_INT	BIT(2)
 
-static void lan8841_ptp_flush_fifo(struct kszphy_ptp_priv *ptp_priv, bool egress)
+static void lan8841_ptp_flush_fifo(struct kszphy_ptp_priv *ptp_priv)
 {
 	struct phy_device *phydev = ptp_priv->phydev;
 	int i;
 
 	for (i = 0; i < FIFO_SIZE; ++i)
-		phy_read_mmd(phydev, 2,
-			     egress ? LAN8841_PTP_TX_MSG_HEADER2 :
-				      LAN8841_PTP_RX_MSG_HEADER2);
+		phy_read_mmd(phydev, 2, LAN8841_PTP_TX_MSG_HEADER2);
 
 	phy_read_mmd(phydev, 2, LAN8841_PTP_INT_STS);
 }
@@ -3789,23 +3749,17 @@ static void lan8841_handle_ptp_interrupt(struct phy_device *phydev)
 		if (status & LAN8841_PTP_INT_STS_PTP_TX_TS_INT)
 			lan8841_ptp_process_tx_ts(ptp_priv);
 
-		if (status & LAN8841_PTP_INT_STS_PTP_RX_TS_INT)
-			lan8841_ptp_process_rx_ts(ptp_priv);
-
 		if (status & LAN8841_PTP_INT_STS_PTP_GPIO_CAP_INT)
 			lan8841_gpio_process_cap(ptp_priv);
 
 		if (status & LAN8841_PTP_INT_STS_PTP_TX_TS_OVRFL_INT) {
-			lan8841_ptp_flush_fifo(ptp_priv, true);
+			lan8841_ptp_flush_fifo(ptp_priv);
 			skb_queue_purge(&ptp_priv->tx_queue);
 		}
 
-		if (status & LAN8841_PTP_INT_STS_PTP_RX_TS_OVRFL_INT) {
-			lan8841_ptp_flush_fifo(ptp_priv, false);
-			skb_queue_purge(&ptp_priv->rx_queue);
-		}
-
-	} while (status);
+	} while (status & (LAN8841_PTP_INT_STS_PTP_TX_TS_INT |
+			   LAN8841_PTP_INT_STS_PTP_GPIO_CAP_INT |
+			   LAN8841_PTP_INT_STS_PTP_TX_TS_OVRFL_INT));
 }
 
 #define LAN8841_INTS_PTP		BIT(9)
@@ -3869,32 +3823,46 @@ static int lan8841_ts_info(struct mii_timestamper *mii_ts,
 #define LAN8841_PTP_INT_EN			260
 #define LAN8841_PTP_INT_EN_PTP_TX_TS_OVRFL_EN	BIT(13)
 #define LAN8841_PTP_INT_EN_PTP_TX_TS_EN		BIT(12)
-#define LAN8841_PTP_INT_EN_PTP_RX_TS_OVRFL_EN	BIT(9)
-#define LAN8841_PTP_INT_EN_PTP_RX_TS_EN		BIT(8)
 
-static void lan8841_ptp_enable_int(struct kszphy_ptp_priv *ptp_priv,
-				   bool enable)
+static void lan8841_ptp_enable_processing(struct kszphy_ptp_priv *ptp_priv,
+					  bool enable)
 {
 	struct phy_device *phydev = ptp_priv->phydev;
 
-	if (enable)
-		/* Enable interrupts */
+	if (enable) {
+		/* Enable interrupts on the TX side */
 		phy_modify_mmd(phydev, 2, LAN8841_PTP_INT_EN,
 			       LAN8841_PTP_INT_EN_PTP_TX_TS_OVRFL_EN |
-			       LAN8841_PTP_INT_EN_PTP_RX_TS_OVRFL_EN |
-			       LAN8841_PTP_INT_EN_PTP_TX_TS_EN |
-			       LAN8841_PTP_INT_EN_PTP_RX_TS_EN,
+			       LAN8841_PTP_INT_EN_PTP_TX_TS_EN,
 			       LAN8841_PTP_INT_EN_PTP_TX_TS_OVRFL_EN |
-			       LAN8841_PTP_INT_EN_PTP_RX_TS_OVRFL_EN |
-			       LAN8841_PTP_INT_EN_PTP_TX_TS_EN |
-			       LAN8841_PTP_INT_EN_PTP_RX_TS_EN);
-	else
-		/* Disable interrupts */
+			       LAN8841_PTP_INT_EN_PTP_TX_TS_EN);
+
+		/* Enable the modification of the frame on RX side,
+		 * this will add the ns and 2 bits of sec in the reserved field
+		 * of the PTP header
+		 */
+		phy_modify_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG,
+			       LAN8841_PTP_RX_MODE,
+			       LAN8841_PTP_INSERT_TS_EN |
+			       LAN8841_PTP_INSERT_TS_32BIT,
+			       LAN8841_PTP_INSERT_TS_EN |
+			       LAN8841_PTP_INSERT_TS_32BIT);
+
+		ptp_schedule_worker(ptp_priv->ptp_clock, 0);
+	} else {
+		/* Disable interrupts on the TX side */
 		phy_modify_mmd(phydev, 2, LAN8841_PTP_INT_EN,
 			       LAN8841_PTP_INT_EN_PTP_TX_TS_OVRFL_EN |
-			       LAN8841_PTP_INT_EN_PTP_RX_TS_OVRFL_EN |
-			       LAN8841_PTP_INT_EN_PTP_TX_TS_EN |
-			       LAN8841_PTP_INT_EN_PTP_RX_TS_EN, 0);
+			       LAN8841_PTP_INT_EN_PTP_TX_TS_EN, 0);
+
+		/* Disable modification of the RX frames */
+		phy_modify_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG,
+			       LAN8841_PTP_RX_MODE,
+			       LAN8841_PTP_INSERT_TS_EN |
+			       LAN8841_PTP_INSERT_TS_32BIT, 0);
+
+		ptp_cancel_worker_sync(ptp_priv->ptp_clock);
+	}
 }
 
 #define LAN8841_PTP_RX_TIMESTAMP_EN		379
@@ -3905,7 +3873,6 @@ static int lan8841_hwtstamp(struct mii_timestamper *mii_ts, struct ifreq *ifr)
 {
 	struct kszphy_ptp_priv *ptp_priv = container_of(mii_ts, struct kszphy_ptp_priv, mii_ts);
 	struct phy_device *phydev = ptp_priv->phydev;
-	struct lan8814_ptp_rx_ts *rx_ts, *tmp;
 	struct hwtstamp_config config;
 	int txcfg = 0, rxcfg = 0;
 	int pkt_ts_enable;
@@ -3969,24 +3936,61 @@ static int lan8841_hwtstamp(struct mii_timestamper *mii_ts, struct ifreq *ifr)
 				PTP_TX_MOD_TX_PTP_SYNC_TS_INSERT_ : 0);
 
 	/* Now enable/disable the timestamping */
-	lan8841_ptp_enable_int(ptp_priv,
-			       config.rx_filter != HWTSTAMP_FILTER_NONE);
-
-	/* In case of multiple starts and stops, these needs to be cleared */
-	list_for_each_entry_safe(rx_ts, tmp, &ptp_priv->rx_ts_list, list) {
-		list_del(&rx_ts->list);
-		kfree(rx_ts);
-	}
+	lan8841_ptp_enable_processing(ptp_priv,
+				      config.rx_filter != HWTSTAMP_FILTER_NONE);
 
-	skb_queue_purge(&ptp_priv->rx_queue);
 	skb_queue_purge(&ptp_priv->tx_queue);
 
-	lan8841_ptp_flush_fifo(ptp_priv, false);
-	lan8841_ptp_flush_fifo(ptp_priv, true);
+	lan8841_ptp_flush_fifo(ptp_priv);
 
 	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ? -EFAULT : 0;
 }
 
+static bool lan8841_rxtstamp(struct mii_timestamper *mii_ts,
+			     struct sk_buff *skb, int type)
+{
+	struct kszphy_ptp_priv *ptp_priv =
+			container_of(mii_ts, struct kszphy_ptp_priv, mii_ts);
+	struct ptp_header *header = ptp_parse_header(skb, type);
+	struct skb_shared_hwtstamps *shhwtstamps;
+	struct timespec64 ts;
+	unsigned long flags;
+	u32 ts_header;
+
+	if (!header)
+		return false;
+
+	if (ptp_priv->rx_filter == HWTSTAMP_FILTER_NONE ||
+	    type == PTP_CLASS_NONE)
+		return false;
+
+	if ((type & ptp_priv->version) == 0 || (type & ptp_priv->layer) == 0)
+		return false;
+
+	spin_lock_irqsave(&ptp_priv->seconds_lock, flags);
+	ts.tv_sec = ptp_priv->seconds;
+	spin_unlock_irqrestore(&ptp_priv->seconds_lock, flags);
+	ts_header = __be32_to_cpu(header->reserved2);
+
+	shhwtstamps = skb_hwtstamps(skb);
+	memset(shhwtstamps, 0, sizeof(*shhwtstamps));
+
+	/* Check for any wrap arounds for the second part */
+	if ((ts.tv_sec & GENMASK(1, 0)) == 0 && (ts_header >> 30) == 3)
+		ts.tv_sec -= GENMASK(1, 0) + 1;
+	else if ((ts.tv_sec & GENMASK(1, 0)) == 3 && (ts_header >> 30) == 0)
+		ts.tv_sec += 1;
+
+	shhwtstamps->hwtstamp =
+		ktime_set((ts.tv_sec & ~(GENMASK(1, 0))) | ts_header >> 30,
+			  ts_header & GENMASK(29, 0));
+	header->reserved2 = 0;
+
+	netif_rx(skb);
+
+	return true;
+}
+
 #define LAN8841_EVENT_A		0
 #define LAN8841_EVENT_B		1
 #define LAN8841_PTP_LTC_TARGET_SEC_HI(event)	((event) == LAN8841_EVENT_A ? 278 : 288)
@@ -4071,6 +4075,7 @@ static int lan8841_ptp_settime64(struct ptp_clock_info *ptp,
 	struct kszphy_ptp_priv *ptp_priv = container_of(ptp, struct kszphy_ptp_priv,
 							ptp_clock_info);
 	struct phy_device *phydev = ptp_priv->phydev;
+	unsigned long flags;
 	int ret;
 
 	/* Set the value to be stored */
@@ -4087,6 +4092,10 @@ static int lan8841_ptp_settime64(struct ptp_clock_info *ptp,
 	ret = lan8841_ptp_update_target(ptp_priv, ts);
 	mutex_unlock(&ptp_priv->ptp_lock);
 
+	spin_lock_irqsave(&ptp_priv->seconds_lock, flags);
+	ptp_priv->seconds = ts->tv_sec;
+	spin_unlock_irqrestore(&ptp_priv->seconds_lock, flags);
+
 	return ret;
 }
 
@@ -4127,6 +4136,30 @@ static int lan8841_ptp_gettime64(struct ptp_clock_info *ptp,
 	return 0;
 }
 
+static void lan8841_ptp_getseconds(struct ptp_clock_info *ptp,
+				   struct timespec64 *ts)
+{
+	struct kszphy_ptp_priv *ptp_priv = container_of(ptp, struct kszphy_ptp_priv,
+							ptp_clock_info);
+	struct phy_device *phydev = ptp_priv->phydev;
+	time64_t s;
+
+	mutex_lock(&ptp_priv->ptp_lock);
+	/* Issue the command to read the LTC */
+	phy_write_mmd(phydev, 2, LAN8841_PTP_CMD_CTL,
+		      LAN8841_PTP_CMD_CTL_PTP_LTC_READ);
+
+	/* Read the LTC */
+	s = phy_read_mmd(phydev, 2, LAN8841_PTP_LTC_RD_SEC_HI);
+	s <<= 16;
+	s |= phy_read_mmd(phydev, 2, LAN8841_PTP_LTC_RD_SEC_MID);
+	s <<= 16;
+	s |= phy_read_mmd(phydev, 2, LAN8841_PTP_LTC_RD_SEC_LO);
+	mutex_unlock(&ptp_priv->ptp_lock);
+
+	set_normalized_timespec64(ts, s, 0);
+}
+
 #define LAN8841_PTP_LTC_STEP_ADJ_LO			276
 #define LAN8841_PTP_LTC_STEP_ADJ_HI			275
 #define LAN8841_PTP_LTC_STEP_ADJ_DIR			BIT(15)
@@ -4629,6 +4662,22 @@ static int lan8841_ptp_enable(struct ptp_clock_info *ptp,
 	return 0;
 }
 
+static long lan8841_ptp_do_aux_work(struct ptp_clock_info *ptp)
+{
+	struct kszphy_ptp_priv *ptp_priv = container_of(ptp, struct kszphy_ptp_priv,
+							ptp_clock_info);
+	struct timespec64 ts;
+	unsigned long flags;
+
+	lan8841_ptp_getseconds(&ptp_priv->ptp_clock_info, &ts);
+
+	spin_lock_irqsave(&ptp_priv->seconds_lock, flags);
+	ptp_priv->seconds = ts.tv_sec;
+	spin_unlock_irqrestore(&ptp_priv->seconds_lock, flags);
+
+	return nsecs_to_jiffies(LAN8841_GET_SEC_LTC_DELAY);
+}
+
 static struct ptp_clock_info lan8841_ptp_clock_info = {
 	.owner		= THIS_MODULE,
 	.name		= "lan8841 ptp",
@@ -4639,6 +4688,7 @@ static struct ptp_clock_info lan8841_ptp_clock_info = {
 	.adjfine	= lan8841_ptp_adjfine,
 	.verify         = lan8841_ptp_verify,
 	.enable         = lan8841_ptp_enable,
+	.do_aux_work	= lan8841_ptp_do_aux_work,
 	.n_per_out      = LAN8841_PTP_GPIO_NUM,
 	.n_ext_ts       = LAN8841_PTP_GPIO_NUM,
 	.n_pins         = LAN8841_PTP_GPIO_NUM,
@@ -4699,13 +4749,11 @@ static int lan8841_probe(struct phy_device *phydev)
 
 	/* Initialize the SW */
 	skb_queue_head_init(&ptp_priv->tx_queue);
-	skb_queue_head_init(&ptp_priv->rx_queue);
-	INIT_LIST_HEAD(&ptp_priv->rx_ts_list);
-	spin_lock_init(&ptp_priv->rx_ts_lock);
 	ptp_priv->phydev = phydev;
 	mutex_init(&ptp_priv->ptp_lock);
+	spin_lock_init(&ptp_priv->seconds_lock);
 
-	ptp_priv->mii_ts.rxtstamp = lan8814_rxtstamp;
+	ptp_priv->mii_ts.rxtstamp = lan8841_rxtstamp;
 	ptp_priv->mii_ts.txtstamp = lan8814_txtstamp;
 	ptp_priv->mii_ts.hwtstamp = lan8841_hwtstamp;
 	ptp_priv->mii_ts.ts_info = lan8841_ts_info;
@@ -4715,6 +4763,16 @@ static int lan8841_probe(struct phy_device *phydev)
 	return 0;
 }
 
+static int lan8841_suspend(struct phy_device *phydev)
+{
+	struct kszphy_priv *priv = phydev->priv;
+	struct kszphy_ptp_priv *ptp_priv = &priv->ptp_priv;
+
+	ptp_cancel_worker_sync(ptp_priv->ptp_clock);
+
+	return genphy_suspend(phydev);
+}
+
 static struct phy_driver ksphy_driver[] = {
 {
 	.phy_id		= PHY_ID_KS8737,
@@ -4938,7 +4996,7 @@ static struct phy_driver ksphy_driver[] = {
 	.get_sset_count = kszphy_get_sset_count,
 	.get_strings	= kszphy_get_strings,
 	.get_stats	= kszphy_get_stats,
-	.suspend	= genphy_suspend,
+	.suspend	= lan8841_suspend,
 	.resume		= genphy_resume,
 	.cable_test_start	= lan8814_cable_test_start,
 	.cable_test_get_status	= ksz886x_cable_test_get_status,
-- 
2.38.0