net: stmmac: Introduce selftests support

We add support for selftests on stmmac driver with 9 basic sanity checks
for now:
	- MAC Loopback
	- PHY Loopback
	- MMC Counters
	- EEE
	- Hash Filter Multicast
	- Perfect Filter Unicast
	- Multicast Filter All
	- Unicast Filter All
	- Flow Control

This allows for fast tracking of regressions in the driver and helps in
spotting mis-configuration of HW.

Changes from v1:
	- Fix build error as module (David)
	- Check for link status before running tests
Changes from RFC v2:
	- Return proper error code in stmmac_test_mmc (Corentin)
	- Use only 1 MMC counter in stmmac_test_mmc (Alexandre)
Changes from RFC v1:
	- Change test_loopback to test_mac_loopback (Andrew)
	- Change timeout to retries (Andrew)
	- Add MC/UC filter tests (Andrew)
	- Only test in offline mode (Andrew)
	- Do not call phy_loopback twice (Alexandre)

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Corentin Labbe <clabbe.montjoie@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -13,6 +13,15 @@ config STMMAC_ETH
 
 if STMMAC_ETH
 
+config STMMAC_SELFTESTS
+	bool "Support for STMMAC Selftests"
+	depends on STMMAC_ETH
+	default n
+	---help---
+	  This adds support for STMMAC Selftests using ethtool. Enable this
+	  feature if you are facing problems with your HW and submit the test
+	  results to the netdev Mailing List.
+
 config STMMAC_PLATFORM
 	tristate "STMMAC Platform bus support"
 	depends on STMMAC_ETH

drivers/net/ethernet/stmicro/stmmac/Makefile

@@ -8,6 +8,8 @@ stmmac-objs:= stmmac_main.o stmmac_ethtool.o stmmac_mdio.o ring_mode.o	\
 	      stmmac_tc.o dwxgmac2_core.o dwxgmac2_dma.o dwxgmac2_descs.o \
 	      $(stmmac-y)
 
+stmmac-$(CONFIG_STMMAC_SELFTESTS) += stmmac_selftests.o
+
 # Ordering matters. Generic driver must be last.
 obj-$(CONFIG_STMMAC_PLATFORM)	+= stmmac-platform.o
 obj-$(CONFIG_DWMAC_ANARION)	+= dwmac-anarion.o

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -229,4 +229,26 @@ int stmmac_dvr_probe(struct device *device,
 void stmmac_disable_eee_mode(struct stmmac_priv *priv);
 bool stmmac_eee_init(struct stmmac_priv *priv);
 
+#if IS_ENABLED(CONFIG_STMMAC_SELFTESTS)
+void stmmac_selftest_run(struct net_device *dev,
+			 struct ethtool_test *etest, u64 *buf);
+void stmmac_selftest_get_strings(struct stmmac_priv *priv, u8 *data);
+int stmmac_selftest_get_count(struct stmmac_priv *priv);
+#else
+static inline void stmmac_selftest_run(struct net_device *dev,
+				       struct ethtool_test *etest, u64 *buf)
+{
+	/* Not enabled */
+}
+static inline void stmmac_selftest_get_strings(struct stmmac_priv *priv,
+					       u8 *data)
+{
+	/* Not enabled */
+}
+static inline int stmmac_selftest_get_count(struct stmmac_priv *priv)
+{
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_STMMAC_SELFTESTS */
+
 #endif /* __STMMAC_H__ */

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

@@ -589,6 +589,8 @@ static int stmmac_get_sset_count(struct net_device *netdev, int sset)
 		}
 
 		return len;
+	case ETH_SS_TEST:
+		return stmmac_selftest_get_count(priv);
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -625,6 +627,9 @@ static void stmmac_get_strings(struct net_device *dev, u32 stringset, u8 *data)
 			p += ETH_GSTRING_LEN;
 		}
 		break;
+	case ETH_SS_TEST:
+		stmmac_selftest_get_strings(priv, p);
+		break;
 	default:
 		WARN_ON(1);
 		break;
@@ -890,6 +895,7 @@ static const struct ethtool_ops stmmac_ethtool_ops = {
 	.nway_reset = phy_ethtool_nway_reset,
 	.get_pauseparam = stmmac_get_pauseparam,
 	.set_pauseparam = stmmac_set_pauseparam,
+	.self_test = stmmac_selftest_run,
 	.get_ethtool_stats = stmmac_get_ethtool_stats,
 	.get_strings = stmmac_get_strings,
 	.get_wol = stmmac_get_wol,