linux-kernel - [PATCH net 3/3] net: bcmgenet: reapply manual settings to the PHY

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Message-Id: <1572980846-37707-4-git-send-email-opendmb@gmail.com>
Date:   Tue,  5 Nov 2019 11:07:26 -0800
From:   Doug Berger <opendmb@...il.com>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list@...adcom.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Doug Berger <opendmb@...il.com>
Subject: [PATCH net 3/3] net: bcmgenet: reapply manual settings to the PHY

The phy_init_hw() function may reset the PHY to a configuration
that does not match manual network settings stored in the phydev
structure. If the phy state machine is polled rather than event
driven this can create a timing hazard where the phy state machine
might alter the settings stored in the phydev structure from the
value read from the BMCR.

This commit follows invocations of phy_init_hw() by the bcmgenet
driver with invocations of the genphy_config_aneg() function to
ensure that the BMCR is written to match the settings held in the
phydev structure. This prevents the risk of manual settings being
accidentally altered.

Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file")
Signed-off-by: Doug Berger <opendmb@...il.com>
---
 drivers/net/ethernet/broadcom/genet/bcmgenet.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index b5255dd08265..1de51811fcb4 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -2612,8 +2612,10 @@ static void bcmgenet_irq_task(struct work_struct *work)
 	spin_unlock_irq(&priv->lock);
 
 	if (status & UMAC_IRQ_PHY_DET_R &&
-	    priv->dev->phydev->autoneg != AUTONEG_ENABLE)
+	    priv->dev->phydev->autoneg != AUTONEG_ENABLE) {
 		phy_init_hw(priv->dev->phydev);
+		genphy_config_aneg(priv->dev->phydev);
+	}
 
 	/* Link UP/DOWN event */
 	if (status & UMAC_IRQ_LINK_EVENT)
@@ -3634,6 +3636,7 @@ static int bcmgenet_resume(struct device *d)
 	phy_init_hw(dev->phydev);
 
 	/* Speed settings must be restored */
+	genphy_config_aneg(dev->phydev);
 	bcmgenet_mii_config(priv->dev, false);
 
 	bcmgenet_set_hw_addr(priv, dev->dev_addr);
-- 
2.7.4