net: bcmgenet: synchronize EXT_RGMII_OOB_CTRL access

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@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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index becc717aad131e0f8577be688db50b0e764b1da9..7c56f76bad115e3afbad6c717ebe7f9628b2b386 100644 (file)
--- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
@@ -264,6 +264,7 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
         * block for the interface to work
         */
        if (priv->ext_phy) {
+               mutex_lock(&phydev->lock);
                reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
                reg &= ~ID_MODE_DIS;
                reg |= id_mode_dis;
@@ -272,6 +273,7 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
                else
                        reg |= RGMII_MODE_EN;
                bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
+               mutex_unlock(&phydev->lock);
        }
 
        if (init)