net: phy: marvell: add support for MV88E6250 family internal PHYs

The embedded PHYs of the 88E6250 family switches are very basic - they
do not even have an Extended Address / Page register.

This adds support for the PHYs to the driver to set up PHY interrupts
and retrieve error stats. To deal with PHYs without a page register,
"simple" variants of all stat handling functions are introduced.

The code should work with all 88E6250 family switches (6250/6220/6071/
6070/6020). The PHY ID 0x01410db0 was read from a 88E6020, under the
assumption that all switches of this family use the same ID. The spec
only lists the prefix 0x01410c00 and leaves the last 10 bits as reserved,
but that seems too unspecific to be useful, as it would cover several
existing PHY IDs already supported by the driver; therefore, the ID read
from the actual hardware is used.

Signed-off-by: Matthias Schiffer <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Link: https://lore.kernel.org/r/0695f699c[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/phy/marvell.c

···
 #define LPA_PAUSE_ASYM_FIBER	0x100
 
 #define NB_FIBER_STATS	1
+#define NB_STAT_MAX	3
 
 MODULE_DESCRIPTION("Marvell PHY driver");
 MODULE_AUTHOR("Andy Fleming");
···
 	{ "phy_receive_errors_fiber", 1, 21, 16},
 };
 
+static_assert(ARRAY_SIZE(marvell_hw_stats) <= NB_STAT_MAX);
+
+/* "simple" stat list + corresponding marvell_get_*_simple functions are used
+ * on PHYs without a page register
+ */
+struct marvell_hw_stat_simple {
+	const char *string;
+	u8 reg;
+	u8 bits;
+};
+
+static const struct marvell_hw_stat_simple marvell_hw_stats_simple[] = {
+	{ "phy_receive_errors", 21, 16},
+};
+
+static_assert(ARRAY_SIZE(marvell_hw_stats_simple) <= NB_STAT_MAX);
+
 enum {
 	M88E3082_VCT_OFF,
 	M88E3082_VCT_PHASE1,
···
 };
 
 struct marvell_priv {
-	u64 stats[ARRAY_SIZE(marvell_hw_stats)];
+	u64 stats[NB_STAT_MAX];
 	char *hwmon_name;
 	struct device *hwmon_dev;
 	bool cable_test_tdr;
···
 		return ARRAY_SIZE(marvell_hw_stats) - NB_FIBER_STATS;
 }
 
+static int marvell_get_sset_count_simple(struct phy_device *phydev)
+{
+	return ARRAY_SIZE(marvell_hw_stats_simple);
+}
+
 static void marvell_get_strings(struct phy_device *phydev, u8 *data)
 {
 	int count = marvell_get_sset_count(phydev);
···
 	for (i = 0; i < count; i++) {
 		strscpy(data + i * ETH_GSTRING_LEN,
 			marvell_hw_stats[i].string, ETH_GSTRING_LEN);
+	}
+}
+
+static void marvell_get_strings_simple(struct phy_device *phydev, u8 *data)
+{
+	int count = marvell_get_sset_count_simple(phydev);
+	int i;
+
+	for (i = 0; i < count; i++) {
+		strscpy(data + i * ETH_GSTRING_LEN,
+			marvell_hw_stats_simple[i].string, ETH_GSTRING_LEN);
 	}
 }
 
···
 	return ret;
 }
 
+static u64 marvell_get_stat_simple(struct phy_device *phydev, int i)
+{
+	struct marvell_hw_stat_simple stat = marvell_hw_stats_simple[i];
+	struct marvell_priv *priv = phydev->priv;
+	int val;
+	u64 ret;
+
+	val = phy_read(phydev, stat.reg);
+	if (val < 0) {
+		ret = U64_MAX;
+	} else {
+		val = val & ((1 << stat.bits) - 1);
+		priv->stats[i] += val;
+		ret = priv->stats[i];
+	}
+
+	return ret;
+}
+
 static void marvell_get_stats(struct phy_device *phydev,
 			      struct ethtool_stats *stats, u64 *data)
 {
···
 
 	for (i = 0; i < count; i++)
 		data[i] = marvell_get_stat(phydev, i);
+}
+
+static void marvell_get_stats_simple(struct phy_device *phydev,
+				     struct ethtool_stats *stats, u64 *data)
+{
+	int count = marvell_get_sset_count_simple(phydev);
+	int i;
+
+	for (i = 0; i < count; i++)
+		data[i] = marvell_get_stat_simple(phydev, i);
 }
 
 static int m88e1510_loopback(struct phy_device *phydev, bool enable)
···
 		.get_stats = marvell_get_stats,
 	},
 	{
+		.phy_id = MARVELL_PHY_ID_88E6250_FAMILY,
+		.phy_id_mask = MARVELL_PHY_ID_MASK,
+		.name = "Marvell 88E6250 Family",
+		/* PHY_BASIC_FEATURES */
+		.probe = marvell_probe,
+		.aneg_done = marvell_aneg_done,
+		.config_intr = marvell_config_intr,
+		.handle_interrupt = marvell_handle_interrupt,
+		.resume = genphy_resume,
+		.suspend = genphy_suspend,
+		.get_sset_count = marvell_get_sset_count_simple,
+		.get_strings = marvell_get_strings_simple,
+		.get_stats = marvell_get_stats_simple,
+	},
+	{
 		.phy_id = MARVELL_PHY_ID_88E6341_FAMILY,
 		.phy_id_mask = MARVELL_PHY_ID_MASK,
 		.name = "Marvell 88E6341 Family",
···
 	{ MARVELL_PHY_ID_88E1540, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E1545, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E3016, MARVELL_PHY_ID_MASK },
+	{ MARVELL_PHY_ID_88E6250_FAMILY, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E6341_FAMILY, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E6390_FAMILY, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E6393_FAMILY, MARVELL_PHY_ID_MASK },

include/linux/marvell_phy.h

···
 /* Marvel 88E1111 in Finisar SFP module with modified PHY ID */
 #define MARVELL_PHY_ID_88E1111_FINISAR	0x01ff0cc0
 
+/* ID from 88E6020, assumed to be the same for the whole 6250 family */
+#define MARVELL_PHY_ID_88E6250_FAMILY	0x01410db0
 /* These Ethernet switch families contain embedded PHYs, but they do
  * not have a model ID. So the switch driver traps reads to the ID2
  * register and returns the switch family ID