| Message ID | 4e6d1cbba2ff16cad5b9ac48ccdf4407f45c7857.1680105013.git.daniel@makrotopia.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | net: dsa: add support for MT7988 | expand |
On Wed, Mar 29, 2023 at 04:59:47PM +0100, Daniel Golle wrote: > 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> Andrew
diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c index ce2665abaaf57..c6fad2d156160 100644 --- a/drivers/net/dsa/mt7530.c +++ b/drivers/net/dsa/mt7530.c @@ -145,13 +145,15 @@ core_write_mmd_indirect(struct mt7530_priv *priv, int prtad, 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
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> --- drivers/net/dsa/mt7530.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)