net: dsa: enable selftest support for all switches by default

Most of generic selftest should be able to work with probably all ethernet
controllers. The DSA switches are not exception, so enable it by default at
least for DSA.

This patch was tested with SJA1105 and AR9331.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

include/net/dsa.h

@@ -577,6 +577,8 @@ struct dsa_switch_ops {
 					 int port, uint64_t *data);
 	void	(*get_stats64)(struct dsa_switch *ds, int port,
 				   struct rtnl_link_stats64 *s);
+	void	(*self_test)(struct dsa_switch *ds, int port,
+			     struct ethtool_test *etest, u64 *data);
 
 	/*
 	 * ethtool Wake-on-LAN

net/dsa/Kconfig

@@ -9,6 +9,7 @@ menuconfig NET_DSA
 	select NET_SWITCHDEV
 	select PHYLINK
 	select NET_DEVLINK
+	select NET_SELFTESTS
 	help
 	  Say Y if you want to enable support for the hardware switches supported
 	  by the Distributed Switch Architecture.

net/dsa/slave.c

@@ -15,6 +15,7 @@
 #include <linux/mdio.h>
 #include <net/rtnetlink.h>
 #include <net/pkt_cls.h>
+#include <net/selftests.h>
 #include <net/tc_act/tc_mirred.h>
 #include <linux/if_bridge.h>
 #include <linux/if_hsr.h>
@@ -748,7 +749,10 @@ static void dsa_slave_get_strings(struct net_device *dev,
 		if (ds->ops->get_strings)
 			ds->ops->get_strings(ds, dp->index, stringset,
 					     data + 4 * len);
+	} else if (stringset ==  ETH_SS_TEST) {
+		net_selftest_get_strings(data);
 	}
+
 }
 
 static void dsa_slave_get_ethtool_stats(struct net_device *dev,
@@ -794,11 +798,27 @@ static int dsa_slave_get_sset_count(struct net_device *dev, int sset)
 			count += ds->ops->get_sset_count(ds, dp->index, sset);
 
 		return count;
+	} else if (sset ==  ETH_SS_TEST) {
+		return net_selftest_get_count();
 	}
 
 	return -EOPNOTSUPP;
 }
 
+static void dsa_slave_net_selftest(struct net_device *ndev,
+				   struct ethtool_test *etest, u64 *buf)
+{
+	struct dsa_port *dp = dsa_slave_to_port(ndev);
+	struct dsa_switch *ds = dp->ds;
+
+	if (ds->ops->self_test) {
+		ds->ops->self_test(ds, dp->index, etest, buf);
+		return;
+	}
+
+	net_selftest(ndev, etest, buf);
+}
+
 static void dsa_slave_get_wol(struct net_device *dev, struct ethtool_wolinfo *w)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
@@ -1630,6 +1650,7 @@ static const struct ethtool_ops dsa_slave_ethtool_ops = {
 	.get_rxnfc		= dsa_slave_get_rxnfc,
 	.set_rxnfc		= dsa_slave_set_rxnfc,
 	.get_ts_info		= dsa_slave_get_ts_info,
+	.self_test		= dsa_slave_net_selftest,
 };
 
 /* legacy way, bypassing the bridge *****************************************/