net: dsa: Add ndo_get_phys_port_name() for CPU port

There is not currently way to infer the port number through sysfs that
is being used as the CPU port number. Overlay a ndo_get_phys_port_name()
operation onto the DSA master network device in order to retrieve that
information.

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

1 files changed, 55 insertions, 1 deletions

diff --git a/net/dsa/master.c b/net/dsa/master.c
index 71bb15f491c8..79e97d2f2d9b 100644
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -126,6 +126,17 @@ static void dsa_master_get_strings(struct net_device *dev, uint32_t stringset,
         }
 }
 
+static int dsa_master_get_phys_port_name(struct net_device *dev,
+                                         char *name, size_t len)
+{
+        struct dsa_port *cpu_dp = dev->dsa_ptr;
+
+        if (snprintf(name, len, "p%d", cpu_dp->index) >= len)
+                return -EINVAL;
+
+        return 0;
+}
+
 static int dsa_master_ethtool_setup(struct net_device *dev)
 {
         struct dsa_port *cpu_dp = dev->dsa_ptr;
@@ -158,6 +169,38 @@ static void dsa_master_ethtool_teardown(struct net_device *dev)
         cpu_dp->orig_ethtool_ops = NULL;
 }
 
+static int dsa_master_ndo_setup(struct net_device *dev)
+{
+        struct dsa_port *cpu_dp = dev->dsa_ptr;
+        struct dsa_switch *ds = cpu_dp->ds;
+        struct net_device_ops *ops;
+
+        if (dev->netdev_ops->ndo_get_phys_port_name)
+                return 0;
+
+        ops = devm_kzalloc(ds->dev, sizeof(*ops), GFP_KERNEL);
+        if (!ops)
+                return -ENOMEM;
+
+        cpu_dp->orig_ndo_ops = dev->netdev_ops;
+        if (cpu_dp->orig_ndo_ops)
+                memcpy(ops, cpu_dp->orig_ndo_ops, sizeof(*ops));
+
+        ops->ndo_get_phys_port_name = dsa_master_get_phys_port_name;
+
+        dev->netdev_ops  = ops;
+
+        return 0;
+}
+
+static void dsa_master_ndo_teardown(struct net_device *dev)
+{
+        struct dsa_port *cpu_dp = dev->dsa_ptr;
+
+        dev->netdev_ops = cpu_dp->orig_ndo_ops;
+        cpu_dp->orig_ndo_ops = NULL;
+}
+
 static ssize_t tagging_show(struct device *d, struct device_attribute *attr,
                             char *buf)
 {
@@ -223,16 +266,27 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
         if (ret)
                 return ret;
 
+        ret = dsa_master_ndo_setup(dev);
+        if (ret)
+                goto out_err_ethtool_teardown;
+
         ret = sysfs_create_group(&dev->dev.kobj, &dsa_group);
         if (ret)
-                dsa_master_ethtool_teardown(dev);
+                goto out_err_ndo_teardown;
+
+        return ret;
 
+out_err_ndo_teardown:
+        dsa_master_ndo_teardown(dev);
+out_err_ethtool_teardown:
+        dsa_master_ethtool_teardown(dev);
         return ret;
 }
 
 void dsa_master_teardown(struct net_device *dev)
 {
         sysfs_remove_group(&dev->dev.kobj, &dsa_group);
+        dsa_master_ndo_teardown(dev);
         dsa_master_ethtool_teardown(dev);
         dsa_master_reset_mtu(dev);