net: dsa: tag_sja1105: split sja1105_tagger_data into private and public sections

The sja1105 driver messes with the tagging protocol's state when PTP RX
timestamping is enabled/disabled. This is fundamentally necessary
because the tagger needs to know what to do when it receives a PTP
packet. If RX timestamping is enabled, then a metadata follow-up frame
is expected, and this holds the (partial) timestamp. So the tagger plays
hide-and-seek with the network stack until it also gets the metadata
frame, and then presents a single packet, the timestamped PTP packet.
But when RX timestamping isn't enabled, there is no metadata frame
expected, so the hide-and-seek game must be turned off and the packet
must be delivered right away to the network stack.

Considering this, we create a pseudo isolation by devising two tagger
methods callable by the switch: one to get the RX timestamping state,
and one to set it. Since we can't export symbols between the tagger and
the switch driver, these methods are exposed through function pointers.

After this change, the public portion of the sja1105_tagger_data
contains only function pointers.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 14 deletions

diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.c b/drivers/net/dsa/sja1105/sja1105_ptp.c
index a9f7e4ae0bb2..be3068a935af 100644
--- a/drivers/net/dsa/sja1105/sja1105_ptp.c
+++ b/drivers/net/dsa/sja1105/sja1105_ptp.c
@@ -58,11 +58,10 @@ enum sja1105_ptp_clk_mode {
 #define ptp_data_to_sja1105(d) \
 		container_of((d), struct sja1105_private, ptp_data)
 
-/* Must be called only with the tagger_data->state bit
- * SJA1105_HWTS_RX_EN cleared
+/* Must be called only while the RX timestamping state of the tagger
+ * is turned off
  */
 static int sja1105_change_rxtstamping(struct sja1105_private *priv,
-				      struct sja1105_tagger_data *tagger_data,
 				      bool on)
 {
 	struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
@@ -74,11 +73,6 @@ static int sja1105_change_rxtstamping(struct sja1105_private *priv,
 	general_params->send_meta1 = on;
 	general_params->send_meta0 = on;
 
-	/* Initialize the meta state machine to a known state */
-	if (tagger_data->stampable_skb) {
-		kfree_skb(tagger_data->stampable_skb);
-		tagger_data->stampable_skb = NULL;
-	}
 	ptp_cancel_worker_sync(ptp_data->clock);
 	skb_queue_purge(&ptp_data->skb_txtstamp_queue);
 	skb_queue_purge(&ptp_data->skb_rxtstamp_queue);
@@ -117,17 +111,17 @@ int sja1105_hwtstamp_set(struct dsa_switch *ds, int port, struct ifreq *ifr)
 		break;
 	}
 
-	if (rx_on != test_bit(SJA1105_HWTS_RX_EN, &tagger_data->state)) {
-		clear_bit(SJA1105_HWTS_RX_EN, &tagger_data->state);
+	if (rx_on != tagger_data->rxtstamp_get_state(ds)) {
+		tagger_data->rxtstamp_set_state(ds, false);
 
-		rc = sja1105_change_rxtstamping(priv, tagger_data, rx_on);
+		rc = sja1105_change_rxtstamping(priv, rx_on);
 		if (rc < 0) {
 			dev_err(ds->dev,
 				"Failed to change RX timestamping: %d\n", rc);
 			return rc;
 		}
 		if (rx_on)
-			set_bit(SJA1105_HWTS_RX_EN, &tagger_data->state);
+			tagger_data->rxtstamp_set_state(ds, true);
 	}
 
 	if (copy_to_user(ifr->ifr_data, &config, sizeof(config)))
@@ -146,7 +140,7 @@ int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr)
 		config.tx_type = HWTSTAMP_TX_ON;
 	else
 		config.tx_type = HWTSTAMP_TX_OFF;
-	if (test_bit(SJA1105_HWTS_RX_EN, &tagger_data->state))
+	if (tagger_data->rxtstamp_get_state(ds))
 		config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
 	else
 		config.rx_filter = HWTSTAMP_FILTER_NONE;
@@ -423,7 +417,7 @@ bool sja1105_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
 
-	if (!test_bit(SJA1105_HWTS_RX_EN, &tagger_data->state))
+	if (!tagger_data->rxtstamp_get_state(ds))
 		return false;
 
 	/* We need to read the full PTP clock to reconstruct the Rx