diff mbox series

[v2,net-next,6/6] net : phy: marvell: Speedup TDR data retrieval by only changing page once

Message ID 20200524152747.745893-7-andrew@lunn.ch
State Superseded
Delegated to: David Miller
Headers show
Series Raw PHY TDR data | expand

Commit Message

Andrew Lunn May 24, 2020, 3:27 p.m. UTC 
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>
---
 drivers/net/phy/marvell.c | 56 +++++++++++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 14 deletions(-)

Comments

Andrew Lunn May 24, 2020, 4:52 p.m. UTC | #1 
On Sun, May 24, 2020 at 05:27:46PM +0200, Andrew Lunn wrote:
> 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.

I've somehow squashed two patches together to from this patch. Which
then explains the 7/6 patch.

Please review the rest of the patches, i will collect comments, and
then repost with this fixed.

     Andrew
diff mbox series

Patch

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index 7e1d95337a28..e9e9d5e688ed 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -214,6 +214,11 @@ 
 #define MII_VCT5_TX_PULSE_CTRL_MAX_AMP			BIT(7)
 #define MII_VCT5_TX_PULSE_CTRL_GT_140m_46_86mV		(0x6 << 0)
 
+/* For TDR measurements less than 11 meters, a short pulse should be
+ * used.
+ */
+#define TDR_SHORT_CABLE_LENGTH	11
+
 #define MII_VCT7_PAIR_0_DISTANCE	0x10
 #define MII_VCT7_PAIR_1_DISTANCE	0x11
 #define MII_VCT7_PAIR_2_DISTANCE	0x12
@@ -1751,15 +1756,12 @@  static int marvell_vct5_wait_complete(struct phy_device *phydev)
 	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 +1775,7 @@  static int marvell_vct5_amplitude(struct phy_device *phydev, int pair)
 	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 +1807,8 @@  static int marvell_vct5_amplitude_distance(struct phy_device *phydev,
 	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 +1817,7 @@  static int marvell_vct5_amplitude_distance(struct phy_device *phydev,
 		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;
 
@@ -1840,29 +1840,57 @@  static int marvell_vct5_amplitude_graph(struct phy_device *phydev)
 {
 	struct marvell_priv *priv = phydev->priv;
 	int distance;
+	u16 width;
+	int page;
 	int err;
 	u16 reg;
 
+	if (priv->first <= TDR_SHORT_CABLE_LENGTH)
+		width = MII_VCT5_TX_PULSE_CTRL_PULSE_WIDTH_32nS;
+	else
+		width = MII_VCT5_TX_PULSE_CTRL_PULSE_WIDTH_128nS;
+
 	reg = MII_VCT5_TX_PULSE_CTRL_GT_140m_46_86mV |
 		MII_VCT5_TX_PULSE_CTRL_DONT_WAIT_LINK_DOWN |
-		MII_VCT5_TX_PULSE_CTRL_MAX_AMP |
-		MII_VCT5_TX_PULSE_CTRL_PULSE_WIDTH_32nS;
+		MII_VCT5_TX_PULSE_CTRL_MAX_AMP | width;
 
 	err = phy_write_paged(phydev, MII_MARVELL_VCT5_PAGE,
 			      MII_VCT5_TX_PULSE_CTRL, reg);
 	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;
+
+		if (distance > TDR_SHORT_CABLE_LENGTH &&
+		    width == MII_VCT5_TX_PULSE_CTRL_PULSE_WIDTH_32nS) {
+			width = MII_VCT5_TX_PULSE_CTRL_PULSE_WIDTH_128nS;
+			reg = MII_VCT5_TX_PULSE_CTRL_GT_140m_46_86mV |
+				MII_VCT5_TX_PULSE_CTRL_DONT_WAIT_LINK_DOWN |
+				MII_VCT5_TX_PULSE_CTRL_MAX_AMP | width;
+			err = __phy_write(phydev, MII_VCT5_TX_PULSE_CTRL, reg);
+			if (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)