netdev: expose DPLL pin handle for netdevice

In case netdevice represents a SyncE port, the user needs to understand
the connection between netdevice and associated DPLL pin. There might me
multiple netdevices pointing to the same pin, in case of VF/SF
implementation.

Add a IFLA Netlink attribute to nest the DPLL pin handle, similar to
how it is implemented for devlink port. Add a struct dpll_pin pointer
to netdev and protect access to it by RTNL. Expose netdev_dpll_pin_set()
and netdev_dpll_pin_clear() helpers to the drivers so they can set/clear
the DPLL pin relationship to netdev.

Note that during the lifetime of struct dpll_pin the pin handle does not
change. Therefore it is save to access it lockless. It is drivers
responsibility to call netdev_dpll_pin_clear() before dpll_pin_put().

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index ccff2b6ef958..cc03a5758d2d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9023,6 +9023,28 @@ bool netdev_port_same_parent_id(struct net_device *a, struct net_device *b)
 }
 EXPORT_SYMBOL(netdev_port_same_parent_id);
 
+static void netdev_dpll_pin_assign(struct net_device *dev, struct dpll_pin *dpll_pin)
+{
+#if IS_ENABLED(CONFIG_DPLL)
+	rtnl_lock();
+	dev->dpll_pin = dpll_pin;
+	rtnl_unlock();
+#endif
+}
+
+void netdev_dpll_pin_set(struct net_device *dev, struct dpll_pin *dpll_pin)
+{
+	WARN_ON(!dpll_pin);
+	netdev_dpll_pin_assign(dev, dpll_pin);
+}
+EXPORT_SYMBOL(netdev_dpll_pin_set);
+
+void netdev_dpll_pin_clear(struct net_device *dev)
+{
+	netdev_dpll_pin_assign(dev, NULL);
+}
+EXPORT_SYMBOL(netdev_dpll_pin_clear);
+
 /**
  *	dev_change_proto_down - set carrier according to proto_down.
  *