[PATCH net-next] net: dsa: Add ndo_get_phys_port_name() for CPU port

[Florian Fainelli]

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.faine...@gmail.com>
---
 include/net/dsa.h |  5 +++++
 net/dsa/master.c  | 56 ++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index b3eefe8e18fd..2f1daf29131a 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -208,6 +208,11 @@ struct dsa_port {
         * Original copy of the master netdev ethtool_ops
         */
        const struct ethtool_ops *orig_ethtool_ops;
+
+       /*
+        * Original copy of the master netdev net_device_ops
+        */
+       const struct net_device_ops *orig_ndo_ops;
 };
 
 struct dsa_switch {
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);
 
-- 
2.17.1