[PATCH net-next 0/2] net: phy: Eliminate unnecessary soft

[PATCH net-next 0/2] net: phy: Eliminate unnecessary soft

[Florian Fainelli]

Hi all,

This patch series eliminates unnecessary software resets of the PHY.
This should hopefully not break anybody's hardware; but I would
appreciate testing to make sure this is is the case.

Sorry for this long email list, I wanted to make sure I reached out to
all people who made changes to the Marvell PHY driver.

Thank you!

Changes since RFT:

- added Tested-by tags from Wang, Dongsheng, Andrew, Chris and Clemens

Florian Fainelli (2):
  net: phy: Stop with excessive soft reset
  net: phy: marvell: Avoid unnecessary soft reset

 drivers/net/phy/marvell.c    | 63 ++++++++++++------------------------
 drivers/net/phy/phy_device.c |  2 --
 2 files changed, 21 insertions(+), 44 deletions(-)

-- 
2.17.1

[PATCH net-next 1/2] net: phy: Stop with excessive soft reset

[Florian Fainelli]

While consolidating the PHY reset in phy_init_hw() an unconditionaly
BMCR soft-reset I became quite trigger happy with those. This was later
on deactivated for the Generic PHY driver on the premise that a prior
software entity (e.g: bootloader) might have applied workarounds in
commit 0878fff1f42c ("net: phy: Do not perform software reset for
Generic PHY").

Since we have a hook to wire-up a soft_reset callback, just use that and
get rid of the call to genphy_soft_reset() entirely. This speeds up
initialization and link establishment for most PHYs out there that do
not require a reset.

Fixes: 87aa9f9c61ad ("net: phy: consolidate PHY reset in phy_init_hw()")
Tested-by: Wang, Dongsheng <dongsheng.wang@hxt-semitech.com>
Tested-by: Chris Healy <cphealy@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/phy/phy_device.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index af64a9320fb0..ee676d75fe02 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -880,8 +880,6 @@ int phy_init_hw(struct phy_device *phydev)
 
 	if (phydev->drv->soft_reset)
 		ret = phydev->drv->soft_reset(phydev);
-	else
-		ret = genphy_soft_reset(phydev);
 
 	if (ret < 0)
 		return ret;
-- 
2.17.1

[PATCH net-next 2/2] net: phy: marvell: Avoid unnecessary soft reset

[Florian Fainelli]

The BMCR.RESET bit on the Marvell PHYs has a special meaning in that
it commits the register writes into the HW for it to latch and be
configured appropriately. Doing software resets causes link drops, and
this is unnecessary disruption if nothing changed.

Determine from marvell_set_polarity()'s return code whether the register value
was changed and if it was, propagate that to the logic that hits the software
reset bit.

This avoids doing unnecessary soft reset if the PHY is configured in
the same state it was previously, this also eliminates the need for a
m88e1111_config_aneg() function since it now is the same as
marvell_config_aneg().

Tested-by: Wang, Dongsheng <dongsheng.wang@hxt-semitech.com>
Tested-by: Chris Healy <cphealy@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/phy/marvell.c | 63 +++++++++++++--------------------------
 1 file changed, 21 insertions(+), 42 deletions(-)

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index f7c69ca34056..b55a7376bfdc 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -265,7 +265,7 @@ static int marvell_set_polarity(struct phy_device *phydev, int polarity)
 			return err;
 	}
 
-	return 0;
+	return val != reg;
 }
 
 static int marvell_set_downshift(struct phy_device *phydev, bool enable,
@@ -287,12 +287,15 @@ static int marvell_set_downshift(struct phy_device *phydev, bool enable,
 
 static int marvell_config_aneg(struct phy_device *phydev)
 {
+	int changed = 0;
 	int err;
 
 	err = marvell_set_polarity(phydev, phydev->mdix_ctrl);
 	if (err < 0)
 		return err;
 
+	changed = err;
+
 	err = phy_write(phydev, MII_M1111_PHY_LED_CONTROL,
 			MII_M1111_PHY_LED_DIRECT);
 	if (err < 0)
@@ -302,7 +305,7 @@ static int marvell_config_aneg(struct phy_device *phydev)
 	if (err < 0)
 		return err;
 
-	if (phydev->autoneg != AUTONEG_ENABLE) {
+	if (phydev->autoneg != AUTONEG_ENABLE || changed) {
 		/* A write to speed/duplex bits (that is performed by
 		 * genphy_config_aneg() call above) must be followed by
 		 * a software reset. Otherwise, the write has no effect.
@@ -350,42 +353,6 @@ static int m88e1101_config_aneg(struct phy_device *phydev)
 	return marvell_config_aneg(phydev);
 }
 
-static int m88e1111_config_aneg(struct phy_device *phydev)
-{
-	int err;
-
-	/* The Marvell PHY has an errata which requires
-	 * that certain registers get written in order
-	 * to restart autonegotiation
-	 */
-	err = genphy_soft_reset(phydev);
-
-	err = marvell_set_polarity(phydev, phydev->mdix_ctrl);
-	if (err < 0)
-		return err;
-
-	err = phy_write(phydev, MII_M1111_PHY_LED_CONTROL,
-			MII_M1111_PHY_LED_DIRECT);
-	if (err < 0)
-		return err;
-
-	err = genphy_config_aneg(phydev);
-	if (err < 0)
-		return err;
-
-	if (phydev->autoneg != AUTONEG_ENABLE) {
-		/* A write to speed/duplex bits (that is performed by
-		 * genphy_config_aneg() call above) must be followed by
-		 * a software reset. Otherwise, the write has no effect.
-		 */
-		err = genphy_soft_reset(phydev);
-		if (err < 0)
-			return err;
-	}
-
-	return 0;
-}
-
 #ifdef CONFIG_OF_MDIO
 /* Set and/or override some configuration registers based on the
  * marvell,reg-init property stored in the of_node for the phydev.
@@ -479,6 +446,7 @@ static int m88e1121_config_aneg_rgmii_delays(struct phy_device *phydev)
 
 static int m88e1121_config_aneg(struct phy_device *phydev)
 {
+	int changed = 0;
 	int err = 0;
 
 	if (phy_interface_is_rgmii(phydev)) {
@@ -487,15 +455,26 @@ static int m88e1121_config_aneg(struct phy_device *phydev)
 			return err;
 	}
 
-	err = genphy_soft_reset(phydev);
+	err = marvell_set_polarity(phydev, phydev->mdix_ctrl);
 	if (err < 0)
 		return err;
 
-	err = marvell_set_polarity(phydev, phydev->mdix_ctrl);
+	changed = err;
+
+	err = genphy_config_aneg(phydev);
 	if (err < 0)
 		return err;
 
-	return genphy_config_aneg(phydev);
+	if (phydev->autoneg != autoneg || changed) {
+		/* A software reset is used to ensure a "commit" of the
+		 * changes is done.
+		 */
+		err = genphy_soft_reset(phydev);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
 }
 
 static int m88e1318_config_aneg(struct phy_device *phydev)
@@ -2067,7 +2046,7 @@ static struct phy_driver marvell_drivers[] = {
 		.flags = PHY_HAS_INTERRUPT,
 		.probe = marvell_probe,
 		.config_init = &m88e1111_config_init,
-		.config_aneg = &m88e1111_config_aneg,
+		.config_aneg = &marvell_config_aneg,
 		.read_status = &marvell_read_status,
 		.ack_interrupt = &marvell_ack_interrupt,
 		.config_intr = &marvell_config_intr,
-- 
2.17.1

Re: [PATCH net-next 0/2] net: phy: Eliminate unnecessary soft

[David Miller]

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Tue, 25 Sep 2018 11:28:44 -0700

> This patch series eliminates unnecessary software resets of the PHY.
> This should hopefully not break anybody's hardware; but I would
> appreciate testing to make sure this is is the case.
> 
> Sorry for this long email list, I wanted to make sure I reached out to
> all people who made changes to the Marvell PHY driver.
> 
> Thank you!
> 
> Changes since RFT:
> 
> - added Tested-by tags from Wang, Dongsheng, Andrew, Chris and Clemens

Series applied.