[RFC PATCH v8 06/10] netdev: expose DPLL pin handle for netdevice

[Arkadiusz Kubalewski <arkadiusz.kubalewski@xxxxxxxxx>]

From: Jiri Pirko <jiri@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@xxxxxxxxx>
---
 drivers/dpll/dpll_netlink.c  | 28 ++++++++++++++++++--------
 include/linux/dpll.h         | 20 +++++++++++++++++++
 include/linux/netdevice.h    | 10 ++++++++++
 include/uapi/linux/if_link.h |  2 ++
 net/core/dev.c               | 22 +++++++++++++++++++++
 net/core/rtnetlink.c         | 38 ++++++++++++++++++++++++++++++++++++
 6 files changed, 112 insertions(+), 8 deletions(-)

diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index 44d9699c9e6c..e6efc17aaf26 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c
@@ -214,10 +214,9 @@ dpll_msg_add_pin_parents(struct sk_buff *msg, struct dpll_pin *pin,
 		nest = nla_nest_start(msg, DPLL_A_PIN_PARENT);
 		if (!nest)
 			return -EMSGSIZE;
-		if (nla_put_u32(msg, DPLL_A_PIN_ID, ppin->id)) {
-			ret = -EMSGSIZE;
+		ret = dpll_msg_add_pin_handle(msg, ppin);
+		if (ret)
 			goto nest_cancel;
-		}
 		if (nla_put_u8(msg, DPLL_A_PIN_STATE, state)) {
 			ret = -EMSGSIZE;
 			goto nest_cancel;
@@ -274,8 +273,9 @@ dpll_cmd_pin_fill_details(struct sk_buff *msg, struct dpll_pin *pin,
 	const struct dpll_pin_properties *prop = pin->prop;
 	int ret;
 
-	if (nla_put_u32(msg, DPLL_A_PIN_ID, pin->id))
-		return -EMSGSIZE;
+	ret = dpll_msg_add_pin_handle(msg, pin);
+	if (ret)
+		return ret;
 	if (nla_put_string(msg, DPLL_A_MODULE_NAME, module_name(pin->module)))
 		return -EMSGSIZE;
 	if (nla_put_64bit(msg, DPLL_A_CLOCK_ID, sizeof(pin->clock_id),
@@ -301,6 +301,20 @@ dpll_cmd_pin_fill_details(struct sk_buff *msg, struct dpll_pin *pin,
 	return 0;
 }
 
+size_t dpll_msg_pin_handle_size(struct dpll_pin *pin)
+{
+	return nla_total_size(4); /* DPLL_A_PIN_ID */
+}
+EXPORT_SYMBOL_GPL(dpll_msg_pin_handle_size);
+
+int dpll_msg_add_pin_handle(struct sk_buff *msg, struct dpll_pin *pin)
+{
+	if (nla_put_u32(msg, DPLL_A_PIN_ID, pin->id))
+		return -EMSGSIZE;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dpll_msg_add_pin_handle);
+
 static int
 __dpll_cmd_pin_dump_one(struct sk_buff *msg, struct dpll_pin *pin,
 			struct netlink_ext_ack *extack)
@@ -690,9 +704,7 @@ dpll_pin_find_from_nlattr(struct genl_info *info, struct sk_buff *skb)
 			    panel_label_attr, package_label_attr);
 	if (!pin)
 		return -EINVAL;
-	if (nla_put_u32(skb, DPLL_A_PIN_ID, pin->id))
-		return -EMSGSIZE;
-	return 0;
+	return dpll_msg_add_pin_handle(skb, pin);
 }
 
 int dpll_nl_pin_id_get_doit(struct sk_buff *skb, struct genl_info *info)
diff --git a/include/linux/dpll.h b/include/linux/dpll.h
index a18bcaa13553..8d085dc92cdd 100644
--- a/include/linux/dpll.h
+++ b/include/linux/dpll.h
@@ -108,6 +108,26 @@ 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);
 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 08fbd4622ccf..c57723b12f75 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -34,6 +34,7 @@
 #include <linux/rculist.h>
 #include <linux/workqueue.h>
 #include <linux/dynamic_queue_limits.h>
+#include <linux/dpll.h>
 
 #include <net/net_namespace.h>
 #ifdef CONFIG_DCB
@@ -2055,6 +2056,9 @@ 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.
  */
@@ -2411,6 +2415,10 @@ 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)
 
@@ -3954,6 +3962,8 @@ 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);
 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);
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 0f6a0fe09bdb..be03c8292cd7 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -377,6 +377,8 @@ enum {
 	IFLA_GSO_IPV4_MAX_SIZE,
 	IFLA_GRO_IPV4_MAX_SIZE,
 
+	IFLA_DPLL_PIN,
+
 	__IFLA_MAX
 };
 
diff --git a/net/core/dev.c b/net/core/dev.c
index 99d99b247bc9..7ae0ce75a5c7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8993,6 +8993,28 @@ 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.
  *
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 41de3a2f29e1..ebe9ae8608fc 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1052,6 +1052,16 @@ 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 */
+
+	if (dev->dpll_pin)
+		size += dpll_msg_pin_handle_size(dev->dpll_pin);
+
+	return size;
+}
+
 static noinline size_t if_nlmsg_size(const struct net_device *dev,
 				     u32 ext_filter_mask)
 {
@@ -1108,6 +1118,7 @@ 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;
 }
 
@@ -1769,6 +1780,30 @@ 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;
+
+	if (dev->dpll_pin) {
+		ret = dpll_msg_add_pin_handle(skb, dev->dpll_pin);
+		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,
@@ -1911,6 +1946,9 @@ 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;
 
-- 
2.37.3