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>

drivers/dpll/dpll_netlink.c

@@ -47,6 +47,18 @@ dpll_msg_add_dev_parent_handle(struct sk_buff *msg, u32 id)
 	return 0;
 }
 
+/**
+ * dpll_msg_pin_handle_size - get size of pin handle attribute for given pin
+ * @pin: pin pointer
+ *
+ * Return: byte size of pin handle attribute for given pin.
+ */
+size_t dpll_msg_pin_handle_size(struct dpll_pin *pin)
+{
+	return pin ? nla_total_size(4) : 0; /* DPLL_A_PIN_ID */
+}
+EXPORT_SYMBOL_GPL(dpll_msg_pin_handle_size);
+
 /**
  * dpll_msg_add_pin_handle - attach pin handle attribute to a given message
  * @msg: pointer to sk_buff message to attach a pin handle
@@ -56,8 +68,7 @@ dpll_msg_add_dev_parent_handle(struct sk_buff *msg, u32 id)
  * * 0 - success
  * * -EMSGSIZE - no space in message to attach pin handle
  */
-static int
-dpll_msg_add_pin_handle(struct sk_buff *msg, struct dpll_pin *pin)
+int dpll_msg_add_pin_handle(struct sk_buff *msg, struct dpll_pin *pin)
 {
 	if (!pin)
 		return 0;
@@ -65,6 +76,7 @@ dpll_msg_add_pin_handle(struct sk_buff *msg, struct dpll_pin *pin)
 		return -EMSGSIZE;
 	return 0;
 }
+EXPORT_SYMBOL_GPL(dpll_msg_add_pin_handle);
 
 static int
 dpll_msg_add_mode(struct sk_buff *msg, struct dpll_device *dpll,

include/linux/dpll.h

@@ -101,6 +101,21 @@ struct dpll_pin_properties {
 	struct dpll_pin_frequency *freq_supported;
 };
 
+#if IS_ENABLED(CONFIG_DPLL)
+size_t dpll_msg_pin_handle_size(struct dpll_pin *pin);
+int dpll_msg_add_pin_handle(struct sk_buff *msg, struct dpll_pin *pin);
+#else
+static inline size_t dpll_msg_pin_handle_size(struct dpll_pin *pin)
+{
+	return 0;
+}
+
+static inline int dpll_msg_add_pin_handle(struct sk_buff *msg, struct dpll_pin *pin)
+{
+	return 0;
+}
+#endif
+
 struct dpll_device *
 dpll_device_get(u64 clock_id, u32 dev_driver_id, struct module *module);
 

include/linux/netdevice.h

@@ -79,6 +79,8 @@ struct xdp_buff;
 struct xdp_frame;
 struct xdp_metadata_ops;
 struct xdp_md;
+/* DPLL specific */
+struct dpll_pin;
 
 typedef u32 xdp_features_t;
 
@@ -2049,6 +2051,9 @@ enum netdev_ml_priv_type {
  *			SET_NETDEV_DEVLINK_PORT macro. This pointer is static
  *			during the time netdevice is registered.
  *
+ *	@dpll_pin: Pointer to the SyncE source pin of a DPLL subsystem,
+ *		   where the clock is recovered.
+ *
  *	FIXME: cleanup struct net_device such that network protocol info
  *	moves out.
  */
@@ -2405,6 +2410,10 @@ struct net_device {
 	struct rtnl_hw_stats64	*offload_xstats_l3;
 
 	struct devlink_port	*devlink_port;
+
+#if IS_ENABLED(CONFIG_DPLL)
+	struct dpll_pin		*dpll_pin;
+#endif
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 
@@ -3940,6 +3949,18 @@ int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name);
 int dev_get_port_parent_id(struct net_device *dev,
 			   struct netdev_phys_item_id *ppid, bool recurse);
 bool netdev_port_same_parent_id(struct net_device *a, struct net_device *b);
+void netdev_dpll_pin_set(struct net_device *dev, struct dpll_pin *dpll_pin);
+void netdev_dpll_pin_clear(struct net_device *dev);
+
+static inline struct dpll_pin *netdev_dpll_pin(const struct net_device *dev)
+{
+#if IS_ENABLED(CONFIG_DPLL)
+	return dev->dpll_pin;
+#else
+	return NULL;
+#endif
+}
+
 struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *dev, bool *again);
 struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 				    struct netdev_queue *txq, int *ret);

include/uapi/linux/if_link.h

@@ -376,7 +376,7 @@ enum {
 
 	IFLA_GSO_IPV4_MAX_SIZE,
 	IFLA_GRO_IPV4_MAX_SIZE,
-
+	IFLA_DPLL_PIN,
 	__IFLA_MAX
 };
 

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.
  *

net/core/rtnetlink.c

@@ -57,6 +57,7 @@
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/addrconf.h>
 #endif
+#include <linux/dpll.h>
 
 #include "dev.h"
 
@@ -1055,6 +1056,15 @@ static size_t rtnl_devlink_port_size(const struct net_device *dev)
 	return size;
 }
 
+static size_t rtnl_dpll_pin_size(const struct net_device *dev)
+{
+	size_t size = nla_total_size(0); /* nest IFLA_DPLL_PIN */
+
+	size += dpll_msg_pin_handle_size(netdev_dpll_pin(dev));
+
+	return size;
+}
+
 static noinline size_t if_nlmsg_size(const struct net_device *dev,
 				     u32 ext_filter_mask)
 {
@@ -1111,6 +1121,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + rtnl_prop_list_size(dev)
 	       + nla_total_size(MAX_ADDR_LEN) /* IFLA_PERM_ADDRESS */
 	       + rtnl_devlink_port_size(dev)
+	       + rtnl_dpll_pin_size(dev)
 	       + 0;
 }
 
@@ -1774,6 +1785,28 @@ static int rtnl_fill_devlink_port(struct sk_buff *skb,
 	return ret;
 }
 
+static int rtnl_fill_dpll_pin(struct sk_buff *skb,
+			      const struct net_device *dev)
+{
+	struct nlattr *dpll_pin_nest;
+	int ret;
+
+	dpll_pin_nest = nla_nest_start(skb, IFLA_DPLL_PIN);
+	if (!dpll_pin_nest)
+		return -EMSGSIZE;
+
+	ret = dpll_msg_add_pin_handle(skb, netdev_dpll_pin(dev));
+	if (ret < 0)
+		goto nest_cancel;
+
+	nla_nest_end(skb, dpll_pin_nest);
+	return 0;
+
+nest_cancel:
+	nla_nest_cancel(skb, dpll_pin_nest);
+	return ret;
+}
+
 static int rtnl_fill_ifinfo(struct sk_buff *skb,
 			    struct net_device *dev, struct net *src_net,
 			    int type, u32 pid, u32 seq, u32 change,
@@ -1916,6 +1949,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
 	if (rtnl_fill_devlink_port(skb, dev))
 		goto nla_put_failure;
 
+	if (rtnl_fill_dpll_pin(skb, dev))
+		goto nla_put_failure;
+
 	nlmsg_end(skb, nlh);
 	return 0;