From: Andrew Lunn <andrew@lunn.ch>
Date: Wed, 27 May 2020 00:21:42 +0200
Subject: net : phy: marvell: Speedup TDR data retrieval by only changing page
 once
Patch-mainline: v5.8-rc1
Git-commit: a618e86da91d259374caff065cc557899dc181ce
References: bsc#1176447

Getting the TDR data requires a large number of MDIO bus
transactions. The number can however be reduced if the page is only
changed once. Add the needed locking to allow this, and make use of
unlocked read/write methods where needed.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/phy/marvell.c |   31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -1751,15 +1751,12 @@ static int marvell_vct5_wait_complete(st
 	int val;
 
 	for (i = 0; i < 32; i++) {
-		val = phy_read_paged(phydev, MII_MARVELL_VCT5_PAGE,
-				     MII_VCT5_CTRL);
+		val = __phy_read(phydev, MII_VCT5_CTRL);
 		if (val < 0)
 			return val;
 
 		if (val & MII_VCT5_CTRL_COMPLETE)
 			return 0;
-
-		usleep_range(1000, 2000);
 	}
 
 	phydev_err(phydev, "Timeout while waiting for cable test to finish\n");
@@ -1773,7 +1770,7 @@ static int marvell_vct5_amplitude(struct
 	int reg;
 
 	reg = MII_VCT5_TX_RX_MDI0_COUPLING + pair;
-	val = phy_read_paged(phydev, MII_MARVELL_VCT5_PAGE, reg);
+	val = __phy_read(phydev, reg);
 
 	if (val < 0)
 		return 0;
@@ -1805,9 +1802,8 @@ static int marvell_vct5_amplitude_distan
 	int mV;
 	int i;
 
-	err = phy_write_paged(phydev, MII_MARVELL_VCT5_PAGE,
-			      MII_VCT5_SAMPLE_POINT_DISTANCE,
-			      distance);
+	err = __phy_write(phydev, MII_VCT5_SAMPLE_POINT_DISTANCE,
+			  distance);
 	if (err)
 		return err;
 
@@ -1816,8 +1812,7 @@ static int marvell_vct5_amplitude_distan
 		MII_VCT5_CTRL_SAMPLES_DEFAULT |
 		MII_VCT5_CTRL_SAMPLE_POINT |
 		MII_VCT5_CTRL_PEEK_HYST_DEFAULT;
-	err = phy_write_paged(phydev, MII_MARVELL_VCT5_PAGE,
-			      MII_VCT5_CTRL, reg);
+	err = __phy_write(phydev, MII_VCT5_CTRL, reg);
 	if (err)
 		return err;
 
@@ -1840,6 +1835,7 @@ static int marvell_vct5_amplitude_graph(
 {
 	struct marvell_priv *priv = phydev->priv;
 	int distance;
+	int page;
 	int err;
 	u16 reg;
 
@@ -1853,16 +1849,27 @@ static int marvell_vct5_amplitude_graph(
 	if (err)
 		return err;
 
+	/* Reading the TDR data is very MDIO heavy. We need to optimize
+	 * access to keep the time to a minimum. So lock the bus once,
+	 * and don't release it until complete. We can then avoid having
+	 * to change the page for every access, greatly speeding things
+	 * up.
+	 */
+	page = phy_select_page(phydev, MII_MARVELL_VCT5_PAGE);
+	if (page < 0)
+		return page;
+
 	for (distance = priv->first;
 	     distance <= priv->last;
 	     distance += priv->step) {
 		err = marvell_vct5_amplitude_distance(phydev, distance,
 						      priv->pair);
 		if (err)
-			return err;
+			goto restore_page;
 	}
 
-	return 0;
+restore_page:
+	return phy_restore_page(phydev, page, err);
 }
 
 static int marvell_cable_test_start_common(struct phy_device *phydev)