Revert "net: dsa: move sja1110_process_meta_tstamp inside the tagging protocol driver"

This reverts commit 6d709cad.

The above change was done to avoid calling symbols exported by the
switch driver from the tagging protocol driver.

With the tagger-owned storage model, we have a new option on our hands,
and that is for the switch driver to provide a data consumer handler in
the form of a function pointer inside the ->connect_tag_protocol()
method. Having a function pointer avoids the problems of the exported
symbols approach.

By creating a handler for metadata frames holding TX timestamps on
SJA1110, we are able to eliminate an skb queue from the tagger data, and
replace it with a simple, and stateless, function pointer. This skb
queue is now handled exclusively by sja1105_ptp.c, which makes the code
easier to follow, as it used to be before the reverted patch.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -2714,6 +2714,7 @@ static int sja1105_connect_tag_protocol(struct dsa_switch *ds,
 	case DSA_TAG_PROTO_SJA1105:
 		tagger_data = sja1105_tagger_data(ds);
 		tagger_data->xmit_work_fn = sja1105_port_deferred_xmit;
+		tagger_data->meta_tstamp_handler = sja1110_process_meta_tstamp;
 		return 0;
 	default:
 		return -EPROTONOSUPPORT;

drivers/net/dsa/sja1105/sja1105_ptp.c

@@ -80,7 +80,7 @@ static int sja1105_change_rxtstamping(struct sja1105_private *priv,
 		tagger_data->stampable_skb = NULL;
 	}
 	ptp_cancel_worker_sync(ptp_data->clock);
-	skb_queue_purge(&tagger_data->skb_txtstamp_queue);
+	skb_queue_purge(&ptp_data->skb_txtstamp_queue);
 	skb_queue_purge(&ptp_data->skb_rxtstamp_queue);
 
 	return sja1105_static_config_reload(priv, SJA1105_RX_HWTSTAMPING);
@@ -456,15 +456,48 @@ bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
 	return priv->info->rxtstamp(ds, port, skb);
 }
 
+void sja1110_process_meta_tstamp(struct dsa_switch *ds, int port, u8 ts_id,
+				 enum sja1110_meta_tstamp dir, u64 tstamp)
+{
+	struct sja1105_private *priv = ds->priv;
+	struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
+	struct sk_buff *skb, *skb_tmp, *skb_match = NULL;
+	struct skb_shared_hwtstamps shwt = {0};
+
+	/* We don't care about RX timestamps on the CPU port */
+	if (dir == SJA1110_META_TSTAMP_RX)
+		return;
+
+	spin_lock(&ptp_data->skb_txtstamp_queue.lock);
+
+	skb_queue_walk_safe(&ptp_data->skb_txtstamp_queue, skb, skb_tmp) {
+		if (SJA1105_SKB_CB(skb)->ts_id != ts_id)
+			continue;
+
+		__skb_unlink(skb, &ptp_data->skb_txtstamp_queue);
+		skb_match = skb;
+
+		break;
+	}
+
+	spin_unlock(&ptp_data->skb_txtstamp_queue.lock);
+
+	if (WARN_ON(!skb_match))
+		return;
+
+	shwt.hwtstamp = ns_to_ktime(sja1105_ticks_to_ns(tstamp));
+	skb_complete_tx_timestamp(skb_match, &shwt);
+}
+
 /* In addition to cloning the skb which is done by the common
  * sja1105_port_txtstamp, we need to generate a timestamp ID and save the
  * packet to the TX timestamping queue.
  */
 void sja1110_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
 {
-	struct sja1105_tagger_data *tagger_data = sja1105_tagger_data(ds);
 	struct sk_buff *clone = SJA1105_SKB_CB(skb)->clone;
 	struct sja1105_private *priv = ds->priv;
+	struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
 	u8 ts_id;
 
 	skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
@@ -479,7 +512,7 @@ void sja1110_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
 
 	spin_unlock(&priv->ts_id_lock);
 
-	skb_queue_tail(&tagger_data->skb_txtstamp_queue, clone);
+	skb_queue_tail(&ptp_data->skb_txtstamp_queue, clone);
 }
 
 /* Called from dsa_skb_tx_timestamp. This callback is just to clone
@@ -919,6 +952,8 @@ int sja1105_ptp_clock_register(struct dsa_switch *ds)
 
 	/* Only used on SJA1105 */
 	skb_queue_head_init(&ptp_data->skb_rxtstamp_queue);
+	/* Only used on SJA1110 */
+	skb_queue_head_init(&ptp_data->skb_txtstamp_queue);
 
 	ptp_data->clock = ptp_clock_register(&ptp_data->caps, ds->dev);
 	if (IS_ERR_OR_NULL(ptp_data->clock))
@@ -934,7 +969,6 @@ int sja1105_ptp_clock_register(struct dsa_switch *ds)
 
 void sja1105_ptp_clock_unregister(struct dsa_switch *ds)
 {
-	struct sja1105_tagger_data *tagger_data = sja1105_tagger_data(ds);
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
 
@@ -943,7 +977,7 @@ void sja1105_ptp_clock_unregister(struct dsa_switch *ds)
 
 	del_timer_sync(&ptp_data->extts_timer);
 	ptp_cancel_worker_sync(ptp_data->clock);
-	skb_queue_purge(&tagger_data->skb_txtstamp_queue);
+	skb_queue_purge(&ptp_data->skb_txtstamp_queue);
 	skb_queue_purge(&ptp_data->skb_rxtstamp_queue);
 	ptp_clock_unregister(ptp_data->clock);
 	ptp_data->clock = NULL;

drivers/net/dsa/sja1105/sja1105_ptp.h

@@ -8,6 +8,21 @@
 
 #if IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP)
 
+/* Timestamps are in units of 8 ns clock ticks (equivalent to
+ * a fixed 125 MHz clock).
+ */
+#define SJA1105_TICK_NS			8
+
+static inline s64 ns_to_sja1105_ticks(s64 ns)
+{
+	return ns / SJA1105_TICK_NS;
+}
+
+static inline s64 sja1105_ticks_to_ns(s64 ticks)
+{
+	return ticks * SJA1105_TICK_NS;
+}
+
 /* Calculate the first base_time in the future that satisfies this
  * relationship:
  *
@@ -62,6 +77,10 @@ struct sja1105_ptp_data {
 	struct timer_list extts_timer;
 	/* Used only on SJA1105 to reconstruct partial timestamps */
 	struct sk_buff_head skb_rxtstamp_queue;
+	/* Used on SJA1110 where meta frames are generated only for
+	 * 2-step TX timestamps
+	 */
+	struct sk_buff_head skb_txtstamp_queue;
 	struct ptp_clock_info caps;
 	struct ptp_clock *clock;
 	struct sja1105_ptp_cmd cmd;
@@ -112,6 +131,9 @@ bool sja1105_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb);
 bool sja1110_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb);
 void sja1110_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb);
 
+void sja1110_process_meta_tstamp(struct dsa_switch *ds, int port, u8 ts_id,
+				 enum sja1110_meta_tstamp dir, u64 tstamp);
+
 #else
 
 struct sja1105_ptp_cmd;
@@ -178,6 +200,8 @@ static inline int sja1105_ptp_commit(struct dsa_switch *ds,
 #define sja1110_rxtstamp NULL
 #define sja1110_txtstamp NULL
 
+#define sja1110_process_meta_tstamp NULL
+
 #endif /* IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP) */
 
 #endif /* _SJA1105_PTP_H */

include/linux/dsa/sja1105.h

@@ -37,6 +37,11 @@
 
 #define SJA1105_HWTS_RX_EN			0
 
+enum sja1110_meta_tstamp {
+	SJA1110_META_TSTAMP_TX = 0,
+	SJA1110_META_TSTAMP_RX = 1,
+};
+
 struct sja1105_deferred_xmit_work {
 	struct dsa_port *dp;
 	struct sk_buff *skb;
@@ -51,12 +56,10 @@ struct sja1105_tagger_data {
 	 */
 	spinlock_t meta_lock;
 	unsigned long state;
-	/* Used on SJA1110 where meta frames are generated only for
-	 * 2-step TX timestamps
-	 */
-	struct sk_buff_head skb_txtstamp_queue;
 	struct kthread_worker *xmit_worker;
 	void (*xmit_work_fn)(struct kthread_work *work);
+	void (*meta_tstamp_handler)(struct dsa_switch *ds, int port, u8 ts_id,
+				    enum sja1110_meta_tstamp dir, u64 tstamp);
 };
 
 struct sja1105_skb_cb {
@@ -69,21 +72,6 @@ struct sja1105_skb_cb {
 #define SJA1105_SKB_CB(skb) \
 	((struct sja1105_skb_cb *)((skb)->cb))
 
-/* Timestamps are in units of 8 ns clock ticks (equivalent to
- * a fixed 125 MHz clock).
- */
-#define SJA1105_TICK_NS			8
-
-static inline s64 ns_to_sja1105_ticks(s64 ns)
-{
-	return ns / SJA1105_TICK_NS;
-}
-
-static inline s64 sja1105_ticks_to_ns(s64 ticks)
-{
-	return ticks * SJA1105_TICK_NS;
-}
-
 static inline struct sja1105_tagger_data *
 sja1105_tagger_data(struct dsa_switch *ds)
 {

net/dsa/tag_sja1105.c

@@ -4,7 +4,6 @@
 #include <linux/if_vlan.h>
 #include <linux/dsa/sja1105.h>
 #include <linux/dsa/8021q.h>
-#include <linux/skbuff.h>
 #include <linux/packing.h>
 #include "dsa_priv.h"
 
@@ -54,11 +53,6 @@
 #define SJA1110_TX_TRAILER_LEN			4
 #define SJA1110_MAX_PADDING_LEN			15
 
-enum sja1110_meta_tstamp {
-	SJA1110_META_TSTAMP_TX = 0,
-	SJA1110_META_TSTAMP_RX = 1,
-};
-
 /* Similar to is_link_local_ether_addr(hdr->h_dest) but also covers PTP */
 static inline bool sja1105_is_link_local(const struct sk_buff *skb)
 {
@@ -539,44 +533,12 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 					      is_meta);
 }
 
-static void sja1110_process_meta_tstamp(struct dsa_switch *ds, int port,
-					u8 ts_id, enum sja1110_meta_tstamp dir,
-					u64 tstamp)
-{
-	struct sja1105_tagger_data *tagger_data = sja1105_tagger_data(ds);
-	struct sk_buff *skb, *skb_tmp, *skb_match = NULL;
-	struct skb_shared_hwtstamps shwt = {0};
-
-	/* We don't care about RX timestamps on the CPU port */
-	if (dir == SJA1110_META_TSTAMP_RX)
-		return;
-
-	spin_lock(&tagger_data->skb_txtstamp_queue.lock);
-
-	skb_queue_walk_safe(&tagger_data->skb_txtstamp_queue, skb, skb_tmp) {
-		if (SJA1105_SKB_CB(skb)->ts_id != ts_id)
-			continue;
-
-		__skb_unlink(skb, &tagger_data->skb_txtstamp_queue);
-		skb_match = skb;
-
-		break;
-	}
-
-	spin_unlock(&tagger_data->skb_txtstamp_queue.lock);
-
-	if (WARN_ON(!skb_match))
-		return;
-
-	shwt.hwtstamp = ns_to_ktime(sja1105_ticks_to_ns(tstamp));
-	skb_complete_tx_timestamp(skb_match, &shwt);
-}
-
 static struct sk_buff *sja1110_rcv_meta(struct sk_buff *skb, u16 rx_header)
 {
 	u8 *buf = dsa_etype_header_pos_rx(skb) + SJA1110_HEADER_LEN;
 	int switch_id = SJA1110_RX_HEADER_SWITCH_ID(rx_header);
 	int n_ts = SJA1110_RX_HEADER_N_TS(rx_header);
+	struct sja1105_tagger_data *tagger_data;
 	struct net_device *master = skb->dev;
 	struct dsa_port *cpu_dp;
 	struct dsa_switch *ds;
@@ -590,6 +552,10 @@ static struct sk_buff *sja1110_rcv_meta(struct sk_buff *skb, u16 rx_header)
 		return NULL;
 	}
 
+	tagger_data = sja1105_tagger_data(ds);
+	if (!tagger_data->meta_tstamp_handler)
+		return NULL;
+
 	for (i = 0; i <= n_ts; i++) {
 		u8 ts_id, source_port, dir;
 		u64 tstamp;
@@ -599,7 +565,7 @@ static struct sk_buff *sja1110_rcv_meta(struct sk_buff *skb, u16 rx_header)
 		dir = (buf[1] & BIT(3)) >> 3;
 		tstamp = be64_to_cpu(*(__be64 *)(buf + 2));
 
-		sja1110_process_meta_tstamp(ds, source_port, ts_id, dir,
+		tagger_data->meta_tstamp_handler(ds, source_port, ts_id, dir,
 						 tstamp);
 
 		buf += SJA1110_META_TSTAMP_SIZE;
@@ -767,8 +733,6 @@ static int sja1105_connect(struct dsa_switch_tree *dst)
 			goto out;
 		}
 
-		/* Only used on SJA1110 */
-		skb_queue_head_init(&tagger_data->skb_txtstamp_queue);
 		spin_lock_init(&tagger_data->meta_lock);
 
 		xmit_worker = kthread_create_worker(0, "dsa%d:%d_xmit",