[PATCH net-next 3/3] net: phy: micrel: Add QUSGMII support and PCH extension

[Maxime Chevallier]

This commit adds support for the PCH extension in the Lan8814 PHY,
allowing the PHY to report RX timestamps to the MAC in the ethernet
preamble.

When using the PCH extension, the PHY will only report the nanoseconds
part of the timestamp in-band, and the seconds part out-of-band.
The main goal in the end is to lower the pressure on the MDIO bus, which
may get pushed to its limit on 48 ports switches doing PTP at a high
rate.

Signed-off-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
---
 drivers/net/phy/micrel.c | 84 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 80 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 9b6973581989..d8084174c5a7 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -149,6 +149,10 @@
 #define LTC_HARD_RESET				0x023F
 #define LTC_HARD_RESET_				BIT(0)
 
+#define TSU_GENERAL_CONFIG			0x2C0
+#define TSU_GENERAL_CONFIG_TSU_ENABLE_		BIT(0)
+#define TSU_GENERAL_CONFIG_TSU_ENABLE_PCH_	BIT(1)
+
 #define TSU_HARD_RESET				0x02C1
 #define TSU_HARD_RESET_				BIT(0)
 
@@ -174,6 +178,7 @@
 
 #define PTP_OPERATING_MODE			0x0241
 #define PTP_OPERATING_MODE_STANDALONE_		BIT(0)
+#define PTP_OPERATING_MODE_PCH_			BIT(1)
 
 #define PTP_TX_MOD				0x028F
 #define PTP_TX_MOD_TX_PTP_SYNC_TS_INSERT_	BIT(12)
@@ -2360,6 +2365,16 @@ static void lan8814_ptp_rx_ts_get(struct phy_device *phydev,
 	*seq_id = lanphy_read_page_reg(phydev, 5, PTP_RX_MSG_HEADER2);
 }
 
+static void lan8814_ptp_rx_ts_get_partial(struct phy_device *phydev,
+					  u32 *seconds, u16 *seq_id)
+{
+	*seconds = lanphy_read_page_reg(phydev, 5, PTP_RX_INGRESS_SEC_HI);
+	*seconds = (*seconds << 16) |
+		   lanphy_read_page_reg(phydev, 5, PTP_RX_INGRESS_SEC_LO);
+
+	*seq_id = lanphy_read_page_reg(phydev, 5, PTP_RX_MSG_HEADER2);
+}
+
 static void lan8814_ptp_tx_ts_get(struct phy_device *phydev,
 				  u32 *seconds, u32 *nano_seconds, u16 *seq_id)
 {
@@ -2504,6 +2519,12 @@ static int lan8814_hwtstamp(struct mii_timestamper *mii_ts,
 	lan8814_flush_fifo(ptp_priv->phydev, false);
 	lan8814_flush_fifo(ptp_priv->phydev, true);
 
+	if (phydev->interface == PHY_INTERFACE_MODE_QUSGMII &&
+	    ptp_priv->hwts_tx_type == HWTSTAMP_TX_ON)
+		phy_inband_ext_set_available(phydev, PHY_INBAND_EXT_PCH_TIMESTAMP);
+	else
+		phy_inband_ext_set_unavailable(phydev, PHY_INBAND_EXT_PCH_TIMESTAMP);
+
 	return 0;
 }
 
@@ -2917,8 +2938,20 @@ static bool lan8814_match_skb(struct kszphy_ptp_priv *ptp_priv,
 
 	if (ret) {
 		shhwtstamps = skb_hwtstamps(skb);
-		memset(shhwtstamps, 0, sizeof(*shhwtstamps));
-		shhwtstamps->hwtstamp = ktime_set(rx_ts->seconds, rx_ts->nsec);
+
+		if (phy_inband_ext_enabled(ptp_priv->phydev, PHY_INBAND_EXT_PCH_TIMESTAMP)) {
+			/* When using the PCH extension, we get the seconds part
+			 * from MDIO accesses, but the seconds part gets
+			 * set by the MAC driver according to the PCH data in the
+			 * preamble
+			 */
+			struct timespec64 ts = ktime_to_timespec64(shhwtstamps->hwtstamp);
+
+			shhwtstamps->hwtstamp = ktime_set(rx_ts->seconds, ts.tv_nsec);
+		} else {
+			memset(shhwtstamps, 0, sizeof(*shhwtstamps));
+			shhwtstamps->hwtstamp = ktime_set(rx_ts->seconds, rx_ts->nsec);
+		}
 		netif_rx(skb);
 	}
 
@@ -2953,8 +2986,18 @@ static void lan8814_get_rx_ts(struct kszphy_ptp_priv *ptp_priv)
 		if (!rx_ts)
 			return;
 
-		lan8814_ptp_rx_ts_get(phydev, &rx_ts->seconds, &rx_ts->nsec,
-				      &rx_ts->seq_id);
+		/* When using PCH mode, the nanoseconds part of the timestamp is
+		 * transmitted inband through the ethernet preamble. We only need
+		 * to retrieve the seconds part along with the seq_id, the MAC
+		 * driver will fill-in the nanoseconds part itself
+		 */
+		if (phy_inband_ext_enabled(ptp_priv->phydev, PHY_INBAND_EXT_PCH_TIMESTAMP))
+			lan8814_ptp_rx_ts_get_partial(phydev, &rx_ts->seconds,
+						      &rx_ts->seq_id);
+		else
+			lan8814_ptp_rx_ts_get(phydev, &rx_ts->seconds,
+					      &rx_ts->nsec, &rx_ts->seq_id);
+
 		lan8814_match_rx_ts(ptp_priv, rx_ts);
 
 		/* If other timestamps are available in the FIFO,
@@ -3240,6 +3283,37 @@ static void lan8814_setup_led(struct phy_device *phydev, int val)
 	lanphy_write_page_reg(phydev, 5, LAN8814_LED_CTRL_1, temp);
 }
 
+static int lan8814_set_inband_ext(struct phy_device *phydev,
+				  enum phy_inband_ext ext, bool enable)
+{
+	u32 tsu_cfg;
+
+	if (ext != PHY_INBAND_EXT_PCH_TIMESTAMP)
+		return -EOPNOTSUPP;
+
+	tsu_cfg = ~TSU_GENERAL_CONFIG_TSU_ENABLE_;
+
+	lanphy_write_page_reg(phydev, 5, TSU_GENERAL_CONFIG, tsu_cfg);
+
+	if (enable) {
+		lanphy_write_page_reg(phydev, 4, PTP_OPERATING_MODE,
+				      PTP_OPERATING_MODE_PCH_);
+
+		tsu_cfg |= TSU_GENERAL_CONFIG_TSU_ENABLE_PCH_;
+	} else {
+		lanphy_write_page_reg(phydev, 4, PTP_OPERATING_MODE,
+				      PTP_OPERATING_MODE_STANDALONE_);
+
+		tsu_cfg &= ~TSU_GENERAL_CONFIG_TSU_ENABLE_PCH_;
+	}
+
+	tsu_cfg |= TSU_GENERAL_CONFIG_TSU_ENABLE_;
+
+	lanphy_write_page_reg(phydev, 5, TSU_GENERAL_CONFIG, tsu_cfg);
+
+	return 0;
+}
+
 static int lan8814_config_init(struct phy_device *phydev)
 {
 	struct kszphy_priv *lan8814 = phydev->priv;
@@ -4805,6 +4879,7 @@ static struct phy_driver ksphy_driver[] = {
 	.phy_id_mask	= MICREL_PHY_ID_MASK,
 	.name		= "Microchip INDY Gigabit Quad PHY",
 	.flags          = PHY_POLL_CABLE_TEST,
+	.inband_ext	= PHY_INBAND_EXT_PCH_TIMESTAMP,
 	.config_init	= lan8814_config_init,
 	.driver_data	= &lan8814_type,
 	.probe		= lan8814_probe,
@@ -4819,6 +4894,7 @@ static struct phy_driver ksphy_driver[] = {
 	.handle_interrupt = lan8814_handle_interrupt,
 	.cable_test_start	= lan8814_cable_test_start,
 	.cable_test_get_status	= ksz886x_cable_test_get_status,
+	.set_inband_ext = lan8814_set_inband_ext,
 }, {
 	.phy_id		= PHY_ID_LAN8804,
 	.phy_id_mask	= MICREL_PHY_ID_MASK,
-- 
2.43.0