[PATCH net-next 11/11] net: dsa: debugfs: add port vlan

[Vivien Didelot]

Add a debug filesystem "vlan" entry to query a port's hardware VLAN
entries through the .port_vlan_dump switch operation.

This is really convenient to query directly the hardware or inspect DSA
or CPU links, since these ports are not exposed to userspace.

Here are the VLAN entries for a CPU port:

    # cat port5/vlan
    vid 1
    vid 42  pvid

Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
---
 net/dsa/debugfs.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/net/dsa/debugfs.c b/net/dsa/debugfs.c
index 98c5068d20da..b00942368d29 100644
--- a/net/dsa/debugfs.c
+++ b/net/dsa/debugfs.c
@@ -286,6 +286,34 @@ static const struct dsa_debugfs_ops dsa_debugfs_tree_ops = {
 	.read = dsa_debugfs_tree_read,
 };
 
+static int dsa_debugfs_vlan_dump_cb(u16 vid, bool pvid, bool untagged,
+				    void *data)
+{
+	struct seq_file *seq = data;
+
+	seq_printf(seq, "vid %d", vid);
+	if (pvid)
+		seq_puts(seq, "  pvid");
+	if (untagged)
+		seq_puts(seq, "  untagged");
+	seq_puts(seq, "\n");
+
+	return 0;
+}
+
+static int dsa_debugfs_vlan_read(struct dsa_switch *ds, int id,
+				 struct seq_file *seq)
+{
+	if (!ds->ops->port_vlan_dump)
+		return -EOPNOTSUPP;
+
+	return ds->ops->port_vlan_dump(ds, id, dsa_debugfs_vlan_dump_cb, seq);
+}
+
+static const struct dsa_debugfs_ops dsa_debugfs_vlan_ops = {
+	.read = dsa_debugfs_vlan_read,
+};
+
 static int dsa_debugfs_create_port(struct dsa_switch *ds, int port)
 {
 	struct dentry *dir;
@@ -318,6 +346,11 @@ static int dsa_debugfs_create_port(struct dsa_switch *ds, int port)
 	if (err)
 		return err;
 
+	err = dsa_debugfs_create_file(ds, dir, "vlan", port,
+				      &dsa_debugfs_vlan_ops);
+	if (err)
+		return err;
+
 	return 0;
 }
 
-- 
2.14.0