[PATCH net-next 09/11] net: dsa: debugfs: add port mdb

[Vivien Didelot]

Add a debug filesystem "mdb" entry to query a port's hardware MDB
entries through the .port_mdb_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.

Signed-off-by: Vivien Didelot <vivien.dide...@savoirfairelinux.com>
---
 net/dsa/debugfs.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/net/dsa/debugfs.c b/net/dsa/debugfs.c
index 8204c62dc9c1..98c5068d20da 100644
--- a/net/dsa/debugfs.c
+++ b/net/dsa/debugfs.c
@@ -140,6 +140,20 @@ static const struct dsa_debugfs_ops dsa_debugfs_fdb_ops = {
        .read = dsa_debugfs_fdb_read,
 };
 
+static int dsa_debugfs_mdb_read(struct dsa_switch *ds, int id,
+                               struct seq_file *seq)
+{
+       if (!ds->ops->port_mdb_dump)
+               return -EOPNOTSUPP;
+
+       /* same callback as for FDB dump */
+       return ds->ops->port_mdb_dump(ds, id, dsa_debugfs_fdb_dump_cb, seq);
+}
+
+static const struct dsa_debugfs_ops dsa_debugfs_mdb_ops = {
+       .read = dsa_debugfs_mdb_read,
+};
+
 static void dsa_debugfs_regs_read_count(struct dsa_switch *ds, int id,
                                        struct seq_file *seq, int count)
 {
@@ -289,6 +303,11 @@ static int dsa_debugfs_create_port(struct dsa_switch *ds, 
int port)
        if (err)
                return err;
 
+       err = dsa_debugfs_create_file(ds, dir, "mdb", port,
+                                     &dsa_debugfs_mdb_ops);
+       if (err)
+               return err;
+
        err = dsa_debugfs_create_file(ds, dir, "regs", port,
                                      &dsa_debugfs_regs_ops);
        if (err)
-- 
2.14.0