Merge branch 'net-generic-selftest-support'

Oleksij Rempel says:

====================
provide generic net selftest support

changes v3:
- make more granular tests
- enable loopback for all PHYs by default
- fix allmodconfig build errors
- poll for link status update after switching to the loopback mode

changes v2:
- make generic selftests available for all networking devices.
- make use of net_selftest* on FEC, ag71xx and all DSA switches.
- add loopback support on more PHYs.

This patch set provides diagnostic capabilities for some iMX, ag71xx or
any DSA based devices. For proper functionality, PHY loopback support is
needed.
So far there is only initial infrastructure with basic tests.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/Kconfig

@@ -20,6 +20,7 @@ if NET_VENDOR_ATHEROS
 config AG71XX
 	tristate "Atheros AR7XXX/AR9XXX built-in ethernet mac support"
 	depends on ATH79
+	select NET_SELFTESTS
 	select PHYLINK
 	help
 	  If you wish to compile a kernel for AR7XXX/91XXX and enable

drivers/net/ethernet/atheros/ag71xx.c

@@ -37,6 +37,7 @@
 #include <linux/reset.h>
 #include <linux/clk.h>
 #include <linux/io.h>
+#include <net/selftests.h>
 
 /* For our NAPI weight bigger does *NOT* mean better - it means more
  * D-cache misses and lots more wasted cycles than we'll ever
@@ -497,12 +498,17 @@ static int ag71xx_ethtool_set_pauseparam(struct net_device *ndev,
 static void ag71xx_ethtool_get_strings(struct net_device *netdev, u32 sset,
 				       u8 *data)
 {
-	if (sset == ETH_SS_STATS) {
-		int i;
+	int i;
 
+	switch (sset) {
+	case ETH_SS_STATS:
 		for (i = 0; i < ARRAY_SIZE(ag71xx_statistics); i++)
 			memcpy(data + i * ETH_GSTRING_LEN,
 			       ag71xx_statistics[i].name, ETH_GSTRING_LEN);
+		break;
+	case ETH_SS_TEST:
+		net_selftest_get_strings(data);
+		break;
 	}
 }
 
@@ -519,9 +525,14 @@ static void ag71xx_ethtool_get_stats(struct net_device *ndev,
 
 static int ag71xx_ethtool_get_sset_count(struct net_device *ndev, int sset)
 {
-	if (sset == ETH_SS_STATS)
+	switch (sset) {
+	case ETH_SS_STATS:
 		return ARRAY_SIZE(ag71xx_statistics);
-	return -EOPNOTSUPP;
+	case ETH_SS_TEST:
+		return net_selftest_get_count();
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 static const struct ethtool_ops ag71xx_ethtool_ops = {
@@ -536,6 +547,7 @@ static const struct ethtool_ops ag71xx_ethtool_ops = {
 	.get_strings			= ag71xx_ethtool_get_strings,
 	.get_ethtool_stats		= ag71xx_ethtool_get_stats,
 	.get_sset_count			= ag71xx_ethtool_get_sset_count,
+	.self_test			= net_selftest,
 };
 
 static int ag71xx_mdio_wait_busy(struct ag71xx *ag)

drivers/net/ethernet/freescale/Kconfig

@@ -26,6 +26,7 @@ config FEC
 		   ARCH_MXC || SOC_IMX28 || COMPILE_TEST)
 	default ARCH_MXC || SOC_IMX28 if ARM
 	select CRC32
+	select NET_SELFTESTS
 	select PHYLIB
 	imply PTP_1588_CLOCK
 	help

drivers/net/ethernet/freescale/fec_main.c

@@ -38,6 +38,7 @@
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <net/ip.h>
+#include <net/selftests.h>
 #include <net/tso.h>
 #include <linux/tcp.h>
 #include <linux/udp.h>
@@ -2482,6 +2483,9 @@ static void fec_enet_get_strings(struct net_device *netdev,
 			memcpy(data + i * ETH_GSTRING_LEN,
 				fec_stats[i].name, ETH_GSTRING_LEN);
 		break;
+	case ETH_SS_TEST:
+		net_selftest_get_strings(data);
+		break;
 	}
 }
 
@@ -2490,6 +2494,8 @@ static int fec_enet_get_sset_count(struct net_device *dev, int sset)
 	switch (sset) {
 	case ETH_SS_STATS:
 		return ARRAY_SIZE(fec_stats);
+	case ETH_SS_TEST:
+		return net_selftest_get_count();
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -2741,6 +2747,7 @@ static const struct ethtool_ops fec_enet_ethtool_ops = {
 	.set_wol		= fec_enet_set_wol,
 	.get_link_ksettings	= phy_ethtool_get_link_ksettings,
 	.set_link_ksettings	= phy_ethtool_set_link_ksettings,
+	.self_test		= net_selftest,
 };
 
 static int fec_enet_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd)

drivers/net/phy/phy.c

@@ -701,7 +701,7 @@ int phy_start_cable_test_tdr(struct phy_device *phydev,
 }
 EXPORT_SYMBOL(phy_start_cable_test_tdr);
 
-static int phy_config_aneg(struct phy_device *phydev)
+int phy_config_aneg(struct phy_device *phydev)
 {
 	if (phydev->drv->config_aneg)
 		return phydev->drv->config_aneg(phydev);
@@ -714,6 +714,7 @@ static int phy_config_aneg(struct phy_device *phydev)
 
 	return genphy_config_aneg(phydev);
 }
+EXPORT_SYMBOL(phy_config_aneg);
 
 /**
  * phy_check_link_status - check link status and set state accordingly

drivers/net/phy/phy_device.c

@@ -1777,6 +1777,9 @@ int phy_loopback(struct phy_device *phydev, bool enable)
 	struct phy_driver *phydrv = to_phy_driver(phydev->mdio.dev.driver);
 	int ret = 0;
 
+	if (!phydrv)
+		return -ENODEV;
+
 	mutex_lock(&phydev->lock);
 
 	if (enable && phydev->loopback_enabled) {
@@ -1789,10 +1792,10 @@ int phy_loopback(struct phy_device *phydev, bool enable)
 		goto out;
 	}
 
-	if (phydev->drv && phydrv->set_loopback)
+	if (phydrv->set_loopback)
 		ret = phydrv->set_loopback(phydev, enable);
 	else
-		ret = -EOPNOTSUPP;
+		ret = genphy_loopback(phydev, enable);
 
 	if (ret)
 		goto out;
@@ -2562,8 +2565,32 @@ EXPORT_SYMBOL(genphy_resume);
 
 int genphy_loopback(struct phy_device *phydev, bool enable)
 {
-	return phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK,
-			  enable ? BMCR_LOOPBACK : 0);
+	if (enable) {
+		u16 val, ctl = BMCR_LOOPBACK;
+		int ret;
+
+		if (phydev->speed == SPEED_1000)
+			ctl |= BMCR_SPEED1000;
+		else if (phydev->speed == SPEED_100)
+			ctl |= BMCR_SPEED100;
+
+		if (phydev->duplex == DUPLEX_FULL)
+			ctl |= BMCR_FULLDPLX;
+
+		phy_modify(phydev, MII_BMCR, ~0, ctl);
+
+		ret = phy_read_poll_timeout(phydev, MII_BMSR, val,
+					    val & BMSR_LSTATUS,
+				    5000, 500000, true);
+		if (ret)
+			return ret;
+	} else {
+		phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, 0);
+
+		phy_config_aneg(phydev);
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL(genphy_loopback);
 

include/linux/phy.h

@@ -1410,6 +1410,7 @@ void phy_disconnect(struct phy_device *phydev);
 void phy_detach(struct phy_device *phydev);
 void phy_start(struct phy_device *phydev);
 void phy_stop(struct phy_device *phydev);
+int phy_config_aneg(struct phy_device *phydev);
 int phy_start_aneg(struct phy_device *phydev);
 int phy_aneg_done(struct phy_device *phydev);
 int phy_speed_down(struct phy_device *phydev, bool sync);

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

include/net/selftests.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_SELFTESTS
+#define _NET_SELFTESTS
+
+#include <linux/ethtool.h>
+
+void net_selftest(struct net_device *ndev, struct ethtool_test *etest,
+		  u64 *buf);
+int net_selftest_get_count(void);
+void net_selftest_get_strings(u8 *data);
+
+#endif /* _NET_SELFTESTS */

net/Kconfig

@@ -429,6 +429,10 @@ config GRO_CELLS
 config SOCK_VALIDATE_XMIT
 	bool
 
+config NET_SELFTESTS
+	def_tristate PHYLIB
+	depends on PHYLIB
+
 config NET_SOCK_MSG
 	bool
 	default n

net/core/Makefile

@@ -33,6 +33,7 @@ obj-$(CONFIG_NET_DEVLINK) += devlink.o
 obj-$(CONFIG_GRO_CELLS) += gro_cells.o
 obj-$(CONFIG_FAILOVER) += failover.o
 ifeq ($(CONFIG_INET),y)
+obj-$(CONFIG_NET_SELFTESTS) += selftests.o
 obj-$(CONFIG_NET_SOCK_MSG) += skmsg.o
 obj-$(CONFIG_BPF_SYSCALL) += sock_map.o
 endif

net/core/selftests.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 Synopsys, Inc. and/or its affiliates.
+ * stmmac Selftests Support
+ *
+ * Author: Jose Abreu <joabreu@synopsys.com>
+ *
+ * Ported from stmmac by:
+ * Copyright (C) 2021 Oleksij Rempel <o.rempel@pengutronix.de>
+ */
+
+#include <linux/phy.h>
+#include <net/selftests.h>
+#include <net/tcp.h>
+#include <net/udp.h>
+
+struct net_packet_attrs {
+	unsigned char *src;
+	unsigned char *dst;
+	u32 ip_src;
+	u32 ip_dst;
+	bool tcp;
+	u16 sport;
+	u16 dport;
+	int timeout;
+	int size;
+	int max_size;
+	u8 id;
+	u16 queue_mapping;
+};
+
+struct net_test_priv {
+	struct net_packet_attrs *packet;
+	struct packet_type pt;
+	struct completion comp;
+	int double_vlan;
+	int vlan_id;
+	int ok;
+};
+
+struct netsfhdr {
+	__be32 version;
+	__be64 magic;
+	u8 id;
+} __packed;
+
+static u8 net_test_next_id;
+
+#define NET_TEST_PKT_SIZE (sizeof(struct ethhdr) + sizeof(struct iphdr) + \
+			   sizeof(struct netsfhdr))
+#define NET_TEST_PKT_MAGIC	0xdeadcafecafedeadULL
+#define NET_LB_TIMEOUT		msecs_to_jiffies(200)
+
+static struct sk_buff *net_test_get_skb(struct net_device *ndev,
+					struct net_packet_attrs *attr)
+{
+	struct sk_buff *skb = NULL;
+	struct udphdr *uhdr = NULL;
+	struct tcphdr *thdr = NULL;
+	struct netsfhdr *shdr;
+	struct ethhdr *ehdr;
+	struct iphdr *ihdr;
+	int iplen, size;
+
+	size = attr->size + NET_TEST_PKT_SIZE;
+
+	if (attr->tcp)
+		size += sizeof(struct tcphdr);
+	else
+		size += sizeof(struct udphdr);
+
+	if (attr->max_size && attr->max_size > size)
+		size = attr->max_size;
+
+	skb = netdev_alloc_skb(ndev, size);
+	if (!skb)
+		return NULL;
+
+	prefetchw(skb->data);
+
+	ehdr = skb_push(skb, ETH_HLEN);
+	skb_reset_mac_header(skb);
+
+	skb_set_network_header(skb, skb->len);
+	ihdr = skb_put(skb, sizeof(*ihdr));
+
+	skb_set_transport_header(skb, skb->len);
+	if (attr->tcp)
+		thdr = skb_put(skb, sizeof(*thdr));
+	else
+		uhdr = skb_put(skb, sizeof(*uhdr));
+
+	eth_zero_addr(ehdr->h_dest);
+
+	if (attr->src)
+		ether_addr_copy(ehdr->h_source, attr->src);
+	if (attr->dst)
+		ether_addr_copy(ehdr->h_dest, attr->dst);
+
+	ehdr->h_proto = htons(ETH_P_IP);
+
+	if (attr->tcp) {
+		thdr->source = htons(attr->sport);
+		thdr->dest = htons(attr->dport);
+		thdr->doff = sizeof(struct tcphdr) / 4;
+		thdr->check = 0;
+	} else {
+		uhdr->source = htons(attr->sport);
+		uhdr->dest = htons(attr->dport);
+		uhdr->len = htons(sizeof(*shdr) + sizeof(*uhdr) + attr->size);
+		if (attr->max_size)
+			uhdr->len = htons(attr->max_size -
+					  (sizeof(*ihdr) + sizeof(*ehdr)));
+		uhdr->check = 0;
+	}
+
+	ihdr->ihl = 5;
+	ihdr->ttl = 32;
+	ihdr->version = 4;
+	if (attr->tcp)
+		ihdr->protocol = IPPROTO_TCP;
+	else
+		ihdr->protocol = IPPROTO_UDP;
+	iplen = sizeof(*ihdr) + sizeof(*shdr) + attr->size;
+	if (attr->tcp)
+		iplen += sizeof(*thdr);
+	else
+		iplen += sizeof(*uhdr);
+
+	if (attr->max_size)
+		iplen = attr->max_size - sizeof(*ehdr);
+
+	ihdr->tot_len = htons(iplen);
+	ihdr->frag_off = 0;
+	ihdr->saddr = htonl(attr->ip_src);
+	ihdr->daddr = htonl(attr->ip_dst);
+	ihdr->tos = 0;
+	ihdr->id = 0;
+	ip_send_check(ihdr);
+
+	shdr = skb_put(skb, sizeof(*shdr));
+	shdr->version = 0;
+	shdr->magic = cpu_to_be64(NET_TEST_PKT_MAGIC);
+	attr->id = net_test_next_id;
+	shdr->id = net_test_next_id++;
+
+	if (attr->size)
+		skb_put(skb, attr->size);
+	if (attr->max_size && attr->max_size > skb->len)
+		skb_put(skb, attr->max_size - skb->len);
+
+	skb->csum = 0;
+	skb->ip_summed = CHECKSUM_PARTIAL;
+	if (attr->tcp) {
+		thdr->check = ~tcp_v4_check(skb->len, ihdr->saddr,
+					    ihdr->daddr, 0);
+		skb->csum_start = skb_transport_header(skb) - skb->head;
+		skb->csum_offset = offsetof(struct tcphdr, check);
+	} else {
+		udp4_hwcsum(skb, ihdr->saddr, ihdr->daddr);
+	}
+
+	skb->protocol = htons(ETH_P_IP);
+	skb->pkt_type = PACKET_HOST;
+	skb->dev = ndev;
+
+	return skb;
+}
+
+static int net_test_loopback_validate(struct sk_buff *skb,
+				      struct net_device *ndev,
+				      struct packet_type *pt,
+				      struct net_device *orig_ndev)
+{
+	struct net_test_priv *tpriv = pt->af_packet_priv;
+	unsigned char *src = tpriv->packet->src;
+	unsigned char *dst = tpriv->packet->dst;
+	struct netsfhdr *shdr;
+	struct ethhdr *ehdr;
+	struct udphdr *uhdr;
+	struct tcphdr *thdr;
+	struct iphdr *ihdr;
+
+	skb = skb_unshare(skb, GFP_ATOMIC);
+	if (!skb)
+		goto out;
+
+	if (skb_linearize(skb))
+		goto out;
+	if (skb_headlen(skb) < (NET_TEST_PKT_SIZE - ETH_HLEN))
+		goto out;
+
+	ehdr = (struct ethhdr *)skb_mac_header(skb);
+	if (dst) {
+		if (!ether_addr_equal_unaligned(ehdr->h_dest, dst))
+			goto out;
+	}
+
+	if (src) {
+		if (!ether_addr_equal_unaligned(ehdr->h_source, src))
+			goto out;
+	}
+
+	ihdr = ip_hdr(skb);
+	if (tpriv->double_vlan)
+		ihdr = (struct iphdr *)(skb_network_header(skb) + 4);
+
+	if (tpriv->packet->tcp) {
+		if (ihdr->protocol != IPPROTO_TCP)
+			goto out;
+
+		thdr = (struct tcphdr *)((u8 *)ihdr + 4 * ihdr->ihl);
+		if (thdr->dest != htons(tpriv->packet->dport))
+			goto out;
+
+		shdr = (struct netsfhdr *)((u8 *)thdr + sizeof(*thdr));
+	} else {
+		if (ihdr->protocol != IPPROTO_UDP)
+			goto out;
+
+		uhdr = (struct udphdr *)((u8 *)ihdr + 4 * ihdr->ihl);
+		if (uhdr->dest != htons(tpriv->packet->dport))
+			goto out;
+
+		shdr = (struct netsfhdr *)((u8 *)uhdr + sizeof(*uhdr));
+	}
+
+	if (shdr->magic != cpu_to_be64(NET_TEST_PKT_MAGIC))
+		goto out;
+	if (tpriv->packet->id != shdr->id)
+		goto out;
+
+	tpriv->ok = true;
+	complete(&tpriv->comp);
+out:
+	kfree_skb(skb);
+	return 0;
+}
+
+static int __net_test_loopback(struct net_device *ndev,
+			       struct net_packet_attrs *attr)
+{
+	struct net_test_priv *tpriv;
+	struct sk_buff *skb = NULL;
+	int ret = 0;
+
+	tpriv = kzalloc(sizeof(*tpriv), GFP_KERNEL);
+	if (!tpriv)
+		return -ENOMEM;
+
+	tpriv->ok = false;
+	init_completion(&tpriv->comp);
+
+	tpriv->pt.type = htons(ETH_P_IP);
+	tpriv->pt.func = net_test_loopback_validate;
+	tpriv->pt.dev = ndev;
+	tpriv->pt.af_packet_priv = tpriv;
+	tpriv->packet = attr;
+	dev_add_pack(&tpriv->pt);
+
+	skb = net_test_get_skb(ndev, attr);
+	if (!skb) {
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+
+	ret = dev_direct_xmit(skb, attr->queue_mapping);
+	if (ret < 0) {
+		goto cleanup;
+	} else if (ret > 0) {
+		ret = -ENETUNREACH;
+		goto cleanup;
+	}
+
+	if (!attr->timeout)
+		attr->timeout = NET_LB_TIMEOUT;
+
+	wait_for_completion_timeout(&tpriv->comp, attr->timeout);
+	ret = tpriv->ok ? 0 : -ETIMEDOUT;
+
+cleanup:
+	dev_remove_pack(&tpriv->pt);
+	kfree(tpriv);
+	return ret;
+}
+
+static int net_test_netif_carrier(struct net_device *ndev)
+{
+	return netif_carrier_ok(ndev) ? 0 : -ENOLINK;
+}
+
+static int net_test_phy_phydev(struct net_device *ndev)
+{
+	return ndev->phydev ? 0 : -EOPNOTSUPP;
+}
+
+static int net_test_phy_loopback_enable(struct net_device *ndev)
+{
+	if (!ndev->phydev)
+		return -EOPNOTSUPP;
+
+	return phy_loopback(ndev->phydev, true);
+}
+
+static int net_test_phy_loopback_disable(struct net_device *ndev)
+{
+	if (!ndev->phydev)
+		return -EOPNOTSUPP;
+
+	return phy_loopback(ndev->phydev, false);
+}
+
+static int net_test_phy_loopback_udp(struct net_device *ndev)
+{
+	struct net_packet_attrs attr = { };
+
+	attr.dst = ndev->dev_addr;
+	return __net_test_loopback(ndev, &attr);
+}
+
+static int net_test_phy_loopback_tcp(struct net_device *ndev)
+{
+	struct net_packet_attrs attr = { };
+
+	attr.dst = ndev->dev_addr;
+	attr.tcp = true;
+	return __net_test_loopback(ndev, &attr);
+}
+
+static const struct net_test {
+	char name[ETH_GSTRING_LEN];
+	int (*fn)(struct net_device *ndev);
+} net_selftests[] = {
+	{
+		.name = "Carrier                       ",
+		.fn = net_test_netif_carrier,
+	}, {
+		.name = "PHY dev is present            ",
+		.fn = net_test_phy_phydev,
+	}, {
+		/* This test should be done before all PHY loopback test */
+		.name = "PHY internal loopback, enable ",
+		.fn = net_test_phy_loopback_enable,
+	}, {
+		.name = "PHY internal loopback, UDP    ",
+		.fn = net_test_phy_loopback_udp,
+	}, {
+		.name = "PHY internal loopback, TCP    ",
+		.fn = net_test_phy_loopback_tcp,
+	}, {
+		/* This test should be done after all PHY loopback test */
+		.name = "PHY internal loopback, disable",
+		.fn = net_test_phy_loopback_disable,
+	},
+};
+
+void net_selftest(struct net_device *ndev, struct ethtool_test *etest, u64 *buf)
+{
+	int count = net_selftest_get_count();
+	int i;
+
+	memset(buf, 0, sizeof(*buf) * count);
+	net_test_next_id = 0;
+
+	if (etest->flags != ETH_TEST_FL_OFFLINE) {
+		netdev_err(ndev, "Only offline tests are supported\n");
+		etest->flags |= ETH_TEST_FL_FAILED;
+		return;
+	}
+
+
+	for (i = 0; i < count; i++) {
+		buf[i] = net_selftests[i].fn(ndev);
+		if (buf[i] && (buf[i] != -EOPNOTSUPP))
+			etest->flags |= ETH_TEST_FL_FAILED;
+	}
+}
+EXPORT_SYMBOL_GPL(net_selftest);
+
+int net_selftest_get_count(void)
+{
+	return ARRAY_SIZE(net_selftests);
+}
+EXPORT_SYMBOL_GPL(net_selftest_get_count);
+
+void net_selftest_get_strings(u8 *data)
+{
+	u8 *p = data;
+	int i;
+
+	for (i = 0; i < net_selftest_get_count(); i++) {
+		snprintf(p, ETH_GSTRING_LEN, "%2d. %s", i + 1,
+			 net_selftests[i].name);
+		p += ETH_GSTRING_LEN;
+	}
+}
+EXPORT_SYMBOL_GPL(net_selftest_get_strings);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");

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 *****************************************/