net: dsa: Add support for DSA specific notifiers

In preparation for communicating a given DSA network device's port
number and switch index, create a specialized DSA notifier and two
events: DSA_PORT_REGISTER and DSA_PORT_UNREGISTER that communicate: the
slave network device (slave_dev), port number and switch number in the
tree.

This will be later used for network device drivers like bcmsysport which
needs to cooperate with its DSA network devices to set-up queue mapping
and scheduling.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 0 deletions

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 51ca2a524a27..832c659ff993 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -14,6 +14,7 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/notifier.h>
 #include <linux/of.h>
 #include <linux/of_mdio.h>
 #include <linux/of_platform.h>
@@ -261,6 +262,28 @@ bool dsa_schedule_work(struct work_struct *work)
         return queue_work(dsa_owq, work);
 }
 
+static ATOMIC_NOTIFIER_HEAD(dsa_notif_chain);
+
+int register_dsa_notifier(struct notifier_block *nb)
+{
+        return atomic_notifier_chain_register(&dsa_notif_chain, nb);
+}
+EXPORT_SYMBOL_GPL(register_dsa_notifier);
+
+int unregister_dsa_notifier(struct notifier_block *nb)
+{
+        return atomic_notifier_chain_unregister(&dsa_notif_chain, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_dsa_notifier);
+
+int call_dsa_notifiers(unsigned long val, struct net_device *dev,
+                       struct dsa_notifier_info *info)
+{
+        info->dev = dev;
+        return atomic_notifier_call_chain(&dsa_notif_chain, val, info);
+}
+EXPORT_SYMBOL_GPL(call_dsa_notifiers);
+
 static int __init dsa_init_module(void)
 {
         int rc;