Merge branch 'net-stmmac-only-use-mac-loopback-for-selftests'

Maxime Chevallier says:

====================
net: stmmac: only use MAC loopback for selftests

stmmac selftests currently use PHY loopback when a PHY is attached, and
fallback to MAC loopback otherwise. PHY loopback however isn't ideal nor
necessary for the tests we are running, that only stress the internal
stmmac features.

Some PHYs bring the carrier state down when in loopback mode, which will
prevent any packet transmission even for ourselves, making selftests
fail for non-stmmac related reasons.

Let's rely only on MAC-side loopback for selftests, making it clear that
any problem found with stmmac selftests are indeed caused by the stmmac
driver, and not external factors.

This was tested on :

 - Cyclone V with RGMII link to KSZ9031
 - Cyclone V with 1000BaseX
 - imx8mp with RGMII link to KSZ9131
 - stm32mp157& with RGMII link to RTL8211F
 - Allwinner H2+ with an internal PHY
====================

Link: https://patch.msgid.link/20260728155728.1193169-1-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c

@@ -11,7 +11,6 @@
 #include <linux/crc32.h>
 #include <linux/ethtool.h>
 #include <linux/ip.h>
-#include <linux/phy.h>
 #include <linux/udp.h>
 #include <net/pkt_cls.h>
 #include <net/pkt_sched.h>
@@ -374,25 +373,6 @@ static int stmmac_test_mac_loopback(struct stmmac_priv *priv)
 	return __stmmac_test_loopback(priv, &attr);
 }
 
-static int stmmac_test_phy_loopback(struct stmmac_priv *priv)
-{
-	struct stmmac_packet_attrs attr = { };
-	int ret;
-
-	if (!priv->dev->phydev)
-		return -EOPNOTSUPP;
-
-	ret = phy_loopback(priv->dev->phydev, true, 0);
-	if (ret)
-		return ret;
-
-	attr.dst = priv->dev->dev_addr;
-	ret = __stmmac_test_loopback(priv, &attr);
-
-	phy_loopback(priv->dev->phydev, false, 0);
-	return ret;
-}
-
 static int stmmac_test_mmc(struct stmmac_priv *priv)
 {
 	struct stmmac_counters initial, final;
@@ -735,13 +715,13 @@ static int stmmac_test_flowctrl_validate(struct sk_buff *skb,
 static int stmmac_test_flowctrl(struct stmmac_priv *priv)
 {
 	unsigned char paddr[ETH_ALEN] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x01};
-	struct phy_device *phydev = priv->dev->phydev;
 	u32 rx_cnt = priv->plat->rx_queues_to_use;
+	struct mac_device_info *mac = priv->hw;
 	struct stmmac_test_priv *tpriv;
 	unsigned int pkt_count;
 	int i, ret = 0;
 
-	if (!phydev || (!phydev->pause && !phydev->asym_pause))
+	if (!(mac->link.caps & MAC_SYM_PAUSE))
 		return -EOPNOTSUPP;
 
 	tpriv = kzalloc_obj(*tpriv);
@@ -1815,10 +1795,6 @@ static int stmmac_test_tbs(struct stmmac_priv *priv)
 	return ret;
 }
 
-#define STMMAC_LOOPBACK_NONE	0
-#define STMMAC_LOOPBACK_MAC	1
-#define STMMAC_LOOPBACK_PHY	2
-
 static const struct stmmac_test {
 	char name[ETH_GSTRING_LEN];
 	int lb;
@@ -1826,131 +1802,96 @@ static const struct stmmac_test {
 } stmmac_selftests[] = {
 	{
 		.name = "MAC Loopback               ",
-		.lb = STMMAC_LOOPBACK_MAC,
 		.fn = stmmac_test_mac_loopback,
-	}, {
-		.name = "PHY Loopback               ",
-		.lb = STMMAC_LOOPBACK_NONE, /* Test will handle it */
-		.fn = stmmac_test_phy_loopback,
 	}, {
 		.name = "MMC Counters               ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_mmc,
 	}, {
 		.name = "EEE                        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_eee,
 	}, {
 		.name = "Hash Filter MC             ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_hfilt,
 	}, {
 		.name = "Perfect Filter UC          ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_pfilt,
 	}, {
 		.name = "MC Filter                  ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_mcfilt,
 	}, {
 		.name = "UC Filter                  ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_ucfilt,
 	}, {
 		.name = "Flow Control               ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_flowctrl,
 	}, {
 		.name = "RSS                        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_rss,
 	}, {
 		.name = "VLAN Filtering             ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_vlanfilt,
 	}, {
 		.name = "VLAN Filtering (perf)      ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_vlanfilt_perfect,
 	}, {
 		.name = "Double VLAN Filter         ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_dvlanfilt,
 	}, {
 		.name = "Double VLAN Filter (perf)  ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_dvlanfilt_perfect,
 	}, {
 		.name = "Flexible RX Parser         ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_rxp,
 	}, {
 		.name = "SA Insertion (desc)        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_desc_sai,
 	}, {
 		.name = "SA Replacement (desc)      ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_desc_sar,
 	}, {
 		.name = "SA Insertion (reg)         ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_reg_sai,
 	}, {
 		.name = "SA Replacement (reg)       ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_reg_sar,
 	}, {
 		.name = "VLAN TX Insertion          ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_vlanoff,
 	}, {
 		.name = "SVLAN TX Insertion         ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_svlanoff,
 	}, {
 		.name = "L3 DA Filtering            ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_l3filt_da,
 	}, {
 		.name = "L3 SA Filtering            ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_l3filt_sa,
 	}, {
 		.name = "L4 DA TCP Filtering        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_l4filt_da_tcp,
 	}, {
 		.name = "L4 SA TCP Filtering        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_l4filt_sa_tcp,
 	}, {
 		.name = "L4 DA UDP Filtering        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_l4filt_da_udp,
 	}, {
 		.name = "L4 SA UDP Filtering        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_l4filt_sa_udp,
 	}, {
 		.name = "ARP Offload                ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_arpoffload,
 	}, {
 		.name = "Jumbo Frame                ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_jumbo,
 	}, {
 		.name = "Multichannel Jumbo         ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_mjumbo,
 	}, {
 		.name = "Split Header               ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_sph,
 	}, {
 		.name = "TBS (ETF Scheduler)        ",
-		.lb = STMMAC_LOOPBACK_PHY,
 		.fn = stmmac_test_tbs,
 	},
 };
@@ -1978,57 +1919,21 @@ void stmmac_selftest_run(struct net_device *dev,
 	/* Wait for queues drain */
 	msleep(200);
 
+	ret = stmmac_set_mac_loopback(priv, priv->ioaddr, true);
+	if (ret) {
+		netdev_err(priv->dev, "Loopback is not supported\n");
+		etest->flags |= ETH_TEST_FL_FAILED;
+		return;
+	}
+
 	for (i = 0; i < count; i++) {
-		ret = 0;
-
-		switch (stmmac_selftests[i].lb) {
-		case STMMAC_LOOPBACK_PHY:
-			ret = -EOPNOTSUPP;
-			if (dev->phydev)
-				ret = phy_loopback(dev->phydev, true, 0);
-			if (!ret)
-				break;
-			fallthrough;
-		case STMMAC_LOOPBACK_MAC:
-			ret = stmmac_set_mac_loopback(priv, priv->ioaddr, true);
-			break;
-		case STMMAC_LOOPBACK_NONE:
-			break;
-		default:
-			ret = -EOPNOTSUPP;
-			break;
-		}
-
-		/*
-		 * First tests will always be MAC / PHY loopback. If any of
-		 * them is not supported we abort earlier.
-		 */
-		if (ret) {
-			netdev_err(priv->dev, "Loopback is not supported\n");
-			etest->flags |= ETH_TEST_FL_FAILED;
-			break;
-		}
-
 		ret = stmmac_selftests[i].fn(priv);
 		if (ret && (ret != -EOPNOTSUPP))
 			etest->flags |= ETH_TEST_FL_FAILED;
 		buf[i] = ret;
-
-		switch (stmmac_selftests[i].lb) {
-		case STMMAC_LOOPBACK_PHY:
-			ret = -EOPNOTSUPP;
-			if (dev->phydev)
-				ret = phy_loopback(dev->phydev, false, 0);
-			if (!ret)
-				break;
-			fallthrough;
-		case STMMAC_LOOPBACK_MAC:
-			stmmac_set_mac_loopback(priv, priv->ioaddr, false);
-			break;
-		default:
-			break;
-		}
 	}
+
+	stmmac_set_mac_loopback(priv, priv->ioaddr, false);
 }
 
 void stmmac_selftest_get_strings(struct stmmac_priv *priv, u8 *data)