[PATCH stable 6.1 2/4] net: bcmgenet: synchronize EXT_RGMII_OOB_CTRL access

Florian Fainelli
2024-05-15T17:02:37Z

From: Doug Berger <opendmb@gmail.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@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: Florian Fainelli <florian.fainelli@broadcom.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