net: dsa: wire up devlink info get

Allow the DSA drivers to implement the devlink call to get info info,
e.g. driver name, firmware version, ASIC ID, etc.

v2:
Combine declaration and the assignment on a single line.
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -612,11 +612,14 @@ struct dsa_switch_ops {
 	bool	(*port_rxtstamp)(struct dsa_switch *ds, int port,
 				 struct sk_buff *skb, unsigned int type);
 
-	/* Devlink parameters */
+	/* Devlink parameters, etc */
 	int	(*devlink_param_get)(struct dsa_switch *ds, u32 id,
 				     struct devlink_param_gset_ctx *ctx);
 	int	(*devlink_param_set)(struct dsa_switch *ds, u32 id,
 				     struct devlink_param_gset_ctx *ctx);
+	int	(*devlink_info_get)(struct dsa_switch *ds,
+				    struct devlink_info_req *req,
+				    struct netlink_ext_ack *extack);
 
 	/*
 	 * MTU change functionality. Switches can also adjust their MRU through

net/dsa/dsa2.c

@@ -21,9 +21,6 @@
 static DEFINE_MUTEX(dsa2_mutex);
 LIST_HEAD(dsa_tree_list);
 
-static const struct devlink_ops dsa_devlink_ops = {
-};
-
 struct dsa_switch *dsa_switch_find(int tree_index, int sw_index)
 {
 	struct dsa_switch_tree *dst;
@@ -382,6 +379,22 @@ static void dsa_port_teardown(struct dsa_port *dp)
 	dp->setup = false;
 }
 
+static int dsa_devlink_info_get(struct devlink *dl,
+				struct devlink_info_req *req,
+				struct netlink_ext_ack *extack)
+{
+	struct dsa_switch *ds = dsa_devlink_to_ds(dl);
+
+	if (ds->ops->devlink_info_get)
+		return ds->ops->devlink_info_get(ds, req, extack);
+
+	return -EOPNOTSUPP;
+}
+
+static const struct devlink_ops dsa_devlink_ops = {
+	.info_get = dsa_devlink_info_get,
+};
+
 static int dsa_switch_setup(struct dsa_switch *ds)
 {
 	struct dsa_devlink_priv *dl_priv;