net: dsa: mt7530: implement .get_stats64

It was reported that the internally calculated counter might differ from
the real one from the Switch MIB. This can happen if the switch directly
forward packets between the ports or offload small packets like ARP
request. In such case, the kernel counter will desync compared to the
real one transmitted and received by the Switch.

To correctly provide the real info to the kernel, implement .get_stats64
that will directly read the current MIB counter from the switch
register.

Signed-off-by: Christian Marangi <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: Ansuel

drivers/net/dsa/mt7530.c

@@ -906,6 +906,51 @@ static void mt7530_get_rmon_stats(struct dsa_switch *ds, int port,
 	*ranges = mt7530_rmon_ranges;
 }
 
+static void mt7530_get_stats64(struct dsa_switch *ds, int port,
+			       struct rtnl_link_stats64 *storage)
+{
+	struct mt7530_priv *priv = ds->priv;
+	uint64_t data;
+
+	/* MIB counter doesn't provide a FramesTransmittedOK but instead
+	 * provide stats for Unicast, Broadcast and Multicast frames separately.
+	 * To simulate a global frame counter, read Unicast and addition Multicast
+	 * and Broadcast later
+	 */
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_RX_UNICAST, 1,
+			       &storage->rx_packets);
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_RX_MULTICAST, 1,
+			       &storage->multicast);
+	storage->rx_packets += storage->multicast;
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_RX_BROADCAST, 1,
+			       &data);
+	storage->rx_packets += data;
+
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_TX_UNICAST, 1,
+			       &storage->tx_packets);
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_TX_MULTICAST, 1,
+			       &data);
+	storage->tx_packets += data;
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_TX_BROADCAST, 1,
+			       &data);
+	storage->tx_packets += data;
+
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_RX_BYTES, 2,
+			       &storage->rx_bytes);
+
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_TX_BYTES, 2,
+			       &storage->tx_bytes);
+
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_RX_DROP, 1,
+			       &storage->rx_dropped);
+
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_TX_DROP, 1,
+			       &storage->tx_dropped);
+
+	mt7530_read_port_stats(priv, port, MT7530_PORT_MIB_RX_CRC_ERR, 1,
+			       &storage->rx_crc_errors);
+}
+
 static void mt7530_get_eth_ctrl_stats(struct dsa_switch *ds, int port,
 				      struct ethtool_eth_ctrl_stats *ctrl_stats)
 {
@@ -3207,6 +3252,7 @@ const struct dsa_switch_ops mt7530_switch_ops = {
 	.get_eth_mac_stats	= mt7530_get_eth_mac_stats,
 	.get_rmon_stats		= mt7530_get_rmon_stats,
 	.get_eth_ctrl_stats	= mt7530_get_eth_ctrl_stats,
+	.get_stats64		= mt7530_get_stats64,
 	.set_ageing_time	= mt7530_set_ageing_time,
 	.port_enable		= mt7530_port_enable,
 	.port_disable		= mt7530_port_disable,