From: Vladimir Oltean vladimir.oltean@nxp.com
[ Upstream commit ed1fe1bebe18884b11e5536b5ac42e3a48960835 ]
There are multi-generational drivers like mv88e6xxx which have code like this:
int mv88e6xxx_port_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr) { if (!chip->info->ptp_support) return -EOPNOTSUPP;
... }
DSA wants to deny PTP timestamping on the master if the switch supports timestamping too. However it currently relies on the presence of the port_hwtstamp_get() callback to determine PTP capability, and this clearly does not work in that case (method is present but returns -EOPNOTSUPP).
We should not deny PTP on the DSA master for those switches which truly do not support hardware timestamping.
Create a dsa_port_supports_hwtstamp() method which actually probes for support by calling port_hwtstamp_get() and seeing whether that returned -EOPNOTSUPP or not.
Fixes: f685e609a301 ("net: dsa: Deny PTP on master if switch supports it") Link: https://patchwork.kernel.org/project/netdevbpf/patch/20221110124345.3901389-... Reported-by: Fabio Estevam festevam@gmail.com Reported-by: Steffen Bätz steffen@innosonix.de Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Tested-by: Fabio Estevam festevam@denx.de Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/dsa/dsa_priv.h | 1 + net/dsa/master.c | 3 +-- net/dsa/port.c | 16 ++++++++++++++++ 3 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h index d9722e49864b..acea875c05e5 100644 --- a/net/dsa/dsa_priv.h +++ b/net/dsa/dsa_priv.h @@ -201,6 +201,7 @@ static inline struct net_device *dsa_master_find_slave(struct net_device *dev, }
/* port.c */ +bool dsa_port_supports_hwtstamp(struct dsa_port *dp, struct ifreq *ifr); void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp, const struct dsa_device_ops *tag_ops); int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age); diff --git a/net/dsa/master.c b/net/dsa/master.c index 2851e44c4cf0..46b1f0455a7b 100644 --- a/net/dsa/master.c +++ b/net/dsa/master.c @@ -204,8 +204,7 @@ static int dsa_master_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) * switch in the tree that is PTP capable. */ list_for_each_entry(dp, &dst->ports, list) - if (dp->ds->ops->port_hwtstamp_get || - dp->ds->ops->port_hwtstamp_set) + if (dsa_port_supports_hwtstamp(dp, ifr)) return -EBUSY; break; } diff --git a/net/dsa/port.c b/net/dsa/port.c index a8895ee3cd60..9ac87063cca8 100644 --- a/net/dsa/port.c +++ b/net/dsa/port.c @@ -109,6 +109,22 @@ static bool dsa_port_can_configure_learning(struct dsa_port *dp) return !err; }
+bool dsa_port_supports_hwtstamp(struct dsa_port *dp, struct ifreq *ifr) +{ + struct dsa_switch *ds = dp->ds; + int err; + + if (!ds->ops->port_hwtstamp_get || !ds->ops->port_hwtstamp_set) + return false; + + /* "See through" shim implementations of the "get" method. + * This will clobber the ifreq structure, but we will either return an + * error, or the master will overwrite it with proper values. + */ + err = ds->ops->port_hwtstamp_get(ds, dp->index, ifr); + return err != -EOPNOTSUPP; +} + int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age) { struct dsa_switch *ds = dp->ds;