mlxbf_gige: add support to display pause frame counters

This patch updates the mlxbf_gige driver to support the
"get_pause_stats()" callback, which enables display of
pause frame counters via "ethtool -I -a oob_net0".

The pause frame counters are only enabled if the "counters_en"
bit is asserted in the LLU general config register. The driver
will only report stats, and thus overwrite the default stats
state of ETHTOOL_STAT_NOT_SET, if "counters_en" is asserted.

Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com>
Signed-off-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/20240305212137.3525-1-davthompson@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_ethtool.c

@@ -124,6 +124,41 @@ static void mlxbf_gige_get_pauseparam(struct net_device *netdev,
 	pause->tx_pause = 1;
 }
 
+static bool mlxbf_gige_llu_counters_enabled(struct mlxbf_gige *priv)
+{
+	u32 data;
+
+	if (priv->hw_version == MLXBF_GIGE_VERSION_BF2) {
+		data = readl(priv->llu_base + MLXBF_GIGE_BF2_LLU_GENERAL_CONFIG);
+		if (data & MLXBF_GIGE_BF2_LLU_COUNTERS_EN)
+			return true;
+	} else {
+		data = readl(priv->llu_base + MLXBF_GIGE_BF3_LLU_GENERAL_CONFIG);
+		if (data & MLXBF_GIGE_BF3_LLU_COUNTERS_EN)
+			return true;
+	}
+
+	return false;
+}
+
+static void mlxbf_gige_get_pause_stats(struct net_device *netdev,
+				       struct ethtool_pause_stats *pause_stats)
+{
+	struct mlxbf_gige *priv = netdev_priv(netdev);
+	u64 data_lo, data_hi;
+
+	/* Read LLU counters to provide stats only if counters are enabled */
+	if (mlxbf_gige_llu_counters_enabled(priv)) {
+		data_lo = readl(priv->llu_base + MLXBF_GIGE_TX_PAUSE_CNT_LO);
+		data_hi = readl(priv->llu_base + MLXBF_GIGE_TX_PAUSE_CNT_HI);
+		pause_stats->tx_pause_frames = (data_hi << 32) | data_lo;
+
+		data_lo = readl(priv->llu_base + MLXBF_GIGE_RX_PAUSE_CNT_LO);
+		data_hi = readl(priv->llu_base + MLXBF_GIGE_RX_PAUSE_CNT_HI);
+		pause_stats->rx_pause_frames = (data_hi << 32) | data_lo;
+	}
+}
+
 const struct ethtool_ops mlxbf_gige_ethtool_ops = {
 	.get_link		= ethtool_op_get_link,
 	.get_ringparam		= mlxbf_gige_get_ringparam,
@@ -134,6 +169,7 @@ const struct ethtool_ops mlxbf_gige_ethtool_ops = {
 	.get_ethtool_stats      = mlxbf_gige_get_ethtool_stats,
 	.nway_reset		= phy_ethtool_nway_reset,
 	.get_pauseparam		= mlxbf_gige_get_pauseparam,
+	.get_pause_stats	= mlxbf_gige_get_pause_stats,
 	.get_link_ksettings	= phy_ethtool_get_link_ksettings,
 	.set_link_ksettings	= phy_ethtool_set_link_ksettings,
 };

drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_regs.h

@@ -99,4 +99,34 @@
 #define MLXBF_GIGE_100M_IPG_SIZE                      119
 #define MLXBF_GIGE_10M_IPG_SIZE                       1199
 
+/* Offsets into OOB LLU block for pause frame counters */
+#define MLXBF_GIGE_BF2_TX_PAUSE_CNT_HI                0x33d8
+#define MLXBF_GIGE_BF2_TX_PAUSE_CNT_LO                0x33dc
+#define MLXBF_GIGE_BF2_RX_PAUSE_CNT_HI                0x3210
+#define MLXBF_GIGE_BF2_RX_PAUSE_CNT_LO                0x3214
+
+#define MLXBF_GIGE_BF3_TX_PAUSE_CNT_HI                0x3a88
+#define MLXBF_GIGE_BF3_TX_PAUSE_CNT_LO                0x3a8c
+#define MLXBF_GIGE_BF3_RX_PAUSE_CNT_HI                0x38c0
+#define MLXBF_GIGE_BF3_RX_PAUSE_CNT_LO                0x38c4
+
+#define MLXBF_GIGE_TX_PAUSE_CNT_HI ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_TX_PAUSE_CNT_HI :    \
+				    MLXBF_GIGE_BF3_TX_PAUSE_CNT_HI)
+#define MLXBF_GIGE_TX_PAUSE_CNT_LO ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_TX_PAUSE_CNT_LO : \
+				    MLXBF_GIGE_BF3_TX_PAUSE_CNT_LO)
+#define MLXBF_GIGE_RX_PAUSE_CNT_HI ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_RX_PAUSE_CNT_HI : \
+				    MLXBF_GIGE_BF3_RX_PAUSE_CNT_HI)
+#define MLXBF_GIGE_RX_PAUSE_CNT_LO ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_RX_PAUSE_CNT_LO : \
+				    MLXBF_GIGE_BF3_RX_PAUSE_CNT_LO)
+
+#define MLXBF_GIGE_BF2_LLU_GENERAL_CONFIG             0x2110
+#define MLXBF_GIGE_BF3_LLU_GENERAL_CONFIG             0x2030
+
+#define MLXBF_GIGE_BF2_LLU_COUNTERS_EN                BIT(0)
+#define MLXBF_GIGE_BF3_LLU_COUNTERS_EN                BIT(4)
+
 #endif /* !defined(__MLXBF_GIGE_REGS_H__) */