net: dsa: sja1105: Add a global sja1105_tagger_data structure

This will be used to keep state for RX timestamping. It is global
because the switch serializes timestampable and meta frames when
trapping them towards the CPU port (lower port indices have higher
priority) and therefore having one state machine per port would create
unnecessary complications.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105.h

@@ -103,6 +103,7 @@ struct sja1105_private {
 	 * the switch doesn't confuse them with one another.
 	 */
 	struct mutex mgmt_lock;
+	struct sja1105_tagger_data tagger_data;
 };
 
 #include "sja1105_dynamic_config.h"

drivers/net/dsa/sja1105/sja1105_main.c

@@ -1828,6 +1828,7 @@ static int sja1105_check_device_id(struct sja1105_private *priv)
 
 static int sja1105_probe(struct spi_device *spi)
 {
+	struct sja1105_tagger_data *tagger_data;
 	struct device *dev = &spi->dev;
 	struct sja1105_private *priv;
 	struct dsa_switch *ds;
@@ -1882,12 +1883,16 @@ static int sja1105_probe(struct spi_device *spi)
 	ds->priv = priv;
 	priv->ds = ds;
 
+	tagger_data = &priv->tagger_data;
+	skb_queue_head_init(&tagger_data->skb_rxtstamp_queue);
+
 	/* Connections between dsa_port and sja1105_port */
 	for (i = 0; i < SJA1105_NUM_PORTS; i++) {
 		struct sja1105_port *sp = &priv->ports[i];
 
 		ds->ports[i].priv = sp;
 		sp->dp = &ds->ports[i];
+		sp->data = tagger_data;
 	}
 	mutex_init(&priv->mgmt_lock);