net: bcmgenet: synchronize EXT_RGMII_OOB_CTRL access

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@vger.kernel.org
Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index 9ada89355747554dc458c311f96333866cf7bc66..86a4aa72b3d4b3ca16aee15e0567036a6a2f6504 100644 (file)
--- 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>
@@ -275,6 +275,7 @@ 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) {
@@ -286,6 +287,7 @@ 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);