diff options
Diffstat (limited to 'target/linux/generic/backport-5.15/790-v6.4-0012-net-dsa-mt7530-skip-locking-if-MDIO-bus-isn-t-presen.patch')
-rw-r--r-- | target/linux/generic/backport-5.15/790-v6.4-0012-net-dsa-mt7530-skip-locking-if-MDIO-bus-isn-t-presen.patch | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.15/790-v6.4-0012-net-dsa-mt7530-skip-locking-if-MDIO-bus-isn-t-presen.patch b/target/linux/generic/backport-5.15/790-v6.4-0012-net-dsa-mt7530-skip-locking-if-MDIO-bus-isn-t-presen.patch new file mode 100644 index 0000000000..95b7cc6afe --- /dev/null +++ b/target/linux/generic/backport-5.15/790-v6.4-0012-net-dsa-mt7530-skip-locking-if-MDIO-bus-isn-t-presen.patch @@ -0,0 +1,47 @@ +From 54d4147a121cec5004a673a58572da346e4458f8 Mon Sep 17 00:00:00 2001 +From: Daniel Golle <daniel@makrotopia.org> +Date: Mon, 3 Apr 2023 02:19:28 +0100 +Subject: [PATCH 15/16] net: dsa: mt7530: skip locking if MDIO bus isn't + present + +As MT7530 and MT7531 internally use 32-bit wide registers, each access +to any register of the switch requires several operations on the MDIO +bus. Hence if there is congruent access, e.g. due to PCS or PHY +polling, this can mess up and interfere with another ongoing register +access sequence. + +However, the MDIO bus mutex is only relevant for MDIO-connected +switches. Prepare switches which have there registers directly mapped +into the SoCs register space via MMIO which do not require such +locking. There we can simply use regmap's default locking mechanism. + +Hence guard mutex operations to only be performed in case of MDIO +connected switches. + +Signed-off-by: Daniel Golle <daniel@makrotopia.org> +Reviewed-by: Andrew Lunn <andrew@lunn.ch> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + drivers/net/dsa/mt7530.c | 6 ++++-- + 1 file changed, 4 insertions(+), 2 deletions(-) + +--- a/drivers/net/dsa/mt7530.c ++++ b/drivers/net/dsa/mt7530.c +@@ -144,13 +144,15 @@ err: + static void + mt7530_mutex_lock(struct mt7530_priv *priv) + { +- mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); ++ if (priv->bus) ++ mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); + } + + static void + mt7530_mutex_unlock(struct mt7530_priv *priv) + { +- mutex_unlock(&priv->bus->mdio_lock); ++ if (priv->bus) ++ mutex_unlock(&priv->bus->mdio_lock); + } + + static void |