netdev - [PATCH stable 6.1 2/4] net: bcmgenet: synchronize EXT_RGMII_OOB

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Message-Id: <20240515170227.1679927-3-florian.fainelli@broadcom.com>
Date: Wed, 15 May 2024 10:02:25 -0700
From: Florian Fainelli <florian.fainelli@...adcom.com>
To: linux-kernel@...r.kernel.org
Cc: broonie@...nel.org,
	Doug Berger <opendmb@...il.com>,
	stable@...r.kernel.org,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	"David S . Miller" <davem@...emloft.net>,
	Florian Fainelli <f.fainelli@...il.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org (open list:BROADCOM GENET ETHERNET DRIVER),
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Sasha Levin <sashal@...nel.org>
Subject: [PATCH stable 6.1 2/4] net: bcmgenet: synchronize EXT_RGMII_OOB_CTRL access

From: Doug Berger <opendmb@...il.com>

commit d85cf67a339685beae1d0aee27b7f61da95455be upstream

The EXT_RGMII_OOB_CTRL register can be written from different
contexts. It is predominantly written from the adjust_link
handler which is synchronized by the phydev->lock, but can
also be written from a different context when configuring the
mii in bcmgenet_mii_config().

The chances of contention are quite low, but it is conceivable
that adjust_link could occur during resume when WoL is enabled
so use the phydev->lock synchronizer in bcmgenet_mii_config()
to be sure.

Fixes: afe3f907d20f ("net: bcmgenet: power on MII block for all MII modes")
Cc: stable@...r.kernel.org
Signed-off-by: Doug Berger <opendmb@...il.com>
Acked-by: Florian Fainelli <florian.fainelli@...adcom.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Florian Fainelli <florian.fainelli@...adcom.com>
---
 drivers/net/ethernet/broadcom/genet/bcmmii.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index cc3afb605b1e..07bb7a4e517c 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
@@ -2,7 +2,7 @@
 /*
  * Broadcom GENET MDIO routines
  *
- * Copyright (c) 2014-2017 Broadcom
+ * Copyright (c) 2014-2024 Broadcom
  */
 
 #include <linux/acpi.h>
@@ -274,6 +274,7 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
 	 * block for the interface to work, unconditionally clear the
 	 * Out-of-band disable since we do not need it.
 	 */
+	mutex_lock(&phydev->lock);
 	reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
 	reg &= ~OOB_DISABLE;
 	if (priv->ext_phy) {
@@ -285,6 +286,7 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
 			reg |= RGMII_MODE_EN;
 	}
 	bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
+	mutex_unlock(&phydev->lock);
 
 	if (init)
 		dev_info(kdev, "configuring instance for %s\n", phy_name);
-- 
2.34.1