[PATCH net-next v2 08/10] net: ethernet: ti: cpts: move rx timestamp processing to ptp worker only

[Grygorii Strashko]

Once CPTS IRQ will be enabled the CPTS irq handler may compete with netif
RX sofirq path and so RX timestamp might not be ready at the moment packet
is processed. As result, packet has to be deferred and processed later.

This patch moves RX timestamp processing tx timestamp processing to PTP
worker always the same way as it's been done for TX timestamps.

  napi_rx->cpts_rx_timestamp
   if ptp_packet then
      push to rxq
      ptp_schedule_worker()

  do_aux_work->cpts_overflow_check
    cpts_process_events()

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---
 drivers/net/ethernet/ti/cpsw.c     |  14 +--
 drivers/net/ethernet/ti/cpsw_new.c |  13 ++-
 drivers/net/ethernet/ti/cpts.c     | 132 ++++++++++++++++++-----------
 drivers/net/ethernet/ti/cpts.h     |   3 +-
 4 files changed, 104 insertions(+), 58 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index c2c5bf87da01..ce2155394830 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -433,17 +433,21 @@ static void cpsw_rx_handler(void *token, int len, int status)
 	skb->dev = ndev;
 	if (status & CPDMA_RX_VLAN_ENCAP)
 		cpsw_rx_vlan_encap(skb);
-	if (priv->rx_ts_enabled)
-		cpts_rx_timestamp(cpsw->cpts, skb);
-	skb->protocol = eth_type_trans(skb, ndev);
 
 	/* unmap page as no netstack skb page recycling */
 	page_pool_release_page(pool, page);
-	netif_receive_skb(skb);
-
 	ndev->stats.rx_bytes += len;
 	ndev->stats.rx_packets++;
 
+	ret = 0;
+	if (priv->rx_ts_enabled)
+		ret = cpts_rx_timestamp(cpsw->cpts, skb);
+
+	if (!ret) {
+		skb->protocol = eth_type_trans(skb, ndev);
+		netif_receive_skb(skb);
+	}
+
 requeue:
 	xmeta = page_address(new_page) + CPSW_XMETA_OFFSET;
 	xmeta->ndev = ndev;
diff --git a/drivers/net/ethernet/ti/cpsw_new.c b/drivers/net/ethernet/ti/cpsw_new.c
index 9209e613257d..8561f0e3b769 100644
--- a/drivers/net/ethernet/ti/cpsw_new.c
+++ b/drivers/net/ethernet/ti/cpsw_new.c
@@ -375,17 +375,22 @@ static void cpsw_rx_handler(void *token, int len, int status)
 	skb->dev = ndev;
 	if (status & CPDMA_RX_VLAN_ENCAP)
 		cpsw_rx_vlan_encap(skb);
-	if (priv->rx_ts_enabled)
-		cpts_rx_timestamp(cpsw->cpts, skb);
-	skb->protocol = eth_type_trans(skb, ndev);
 
 	/* unmap page as no netstack skb page recycling */
 	page_pool_release_page(pool, page);
-	netif_receive_skb(skb);
 
 	ndev->stats.rx_bytes += len;
 	ndev->stats.rx_packets++;
 
+	ret = 0;
+	if (priv->rx_ts_enabled)
+		ret = cpts_rx_timestamp(cpsw->cpts, skb);
+
+	if (!ret) {
+		skb->protocol = eth_type_trans(skb, ndev);
+		netif_receive_skb(skb);
+	}
+
 requeue:
 	xmeta = page_address(new_page) + CPSW_XMETA_OFFSET;
 	xmeta->ndev = ndev;
diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index 3cfa0f78287b..fe70eb677b88 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -311,6 +311,66 @@ static bool cpts_match_tx_ts(struct cpts *cpts, struct cpts_event *event)
 	return found;
 }
 
+static bool cpts_match_rx_ts(struct cpts *cpts, struct cpts_event *event)
+{
+	struct sk_buff_head rxq_list;
+	struct sk_buff_head tempq;
+	struct sk_buff *skb, *tmp;
+	unsigned long flags;
+	bool found = false;
+	u32 mtype_seqid;
+
+	mtype_seqid = event->high &
+		      ((MESSAGE_TYPE_MASK << MESSAGE_TYPE_SHIFT) |
+		       (SEQUENCE_ID_MASK << SEQUENCE_ID_SHIFT) |
+		       (EVENT_TYPE_MASK << EVENT_TYPE_SHIFT));
+
+	__skb_queue_head_init(&rxq_list);
+	__skb_queue_head_init(&tempq);
+
+	spin_lock_irqsave(&cpts->rxq.lock, flags);
+	skb_queue_splice_init(&cpts->rxq, &rxq_list);
+	spin_unlock_irqrestore(&cpts->rxq.lock, flags);
+
+	skb_queue_walk_safe(&rxq_list, skb, tmp) {
+		struct skb_shared_hwtstamps *ssh;
+		struct cpts_skb_cb_data *skb_cb =
+					(struct cpts_skb_cb_data *)skb->cb;
+
+		if (mtype_seqid == skb_cb->skb_mtype_seqid) {
+			__skb_unlink(skb, &rxq_list);
+			ssh = skb_hwtstamps(skb);
+			memset(ssh, 0, sizeof(*ssh));
+			ssh->hwtstamp = ns_to_ktime(event->timestamp);
+			found = true;
+			dev_dbg(cpts->dev, "match rx timestamp mtype_seqid %08x\n",
+				mtype_seqid);
+			__skb_queue_tail(&tempq, skb);
+			break;
+		}
+
+		if (time_after(jiffies, skb_cb->tmo)) {
+			/* timeout any expired skbs */
+			dev_dbg(cpts->dev, "expiring rx timestamp\n");
+			__skb_unlink(skb, &rxq_list);
+			__skb_queue_tail(&tempq, skb);
+		}
+	}
+
+	spin_lock_irqsave(&cpts->rxq.lock, flags);
+	skb_queue_splice(&rxq_list, &cpts->rxq);
+	spin_unlock_irqrestore(&cpts->rxq.lock, flags);
+
+	local_bh_disable();
+	while ((skb = __skb_dequeue(&tempq))) {
+		skb->protocol = eth_type_trans(skb, skb->dev);
+		netif_receive_skb(skb);
+	}
+	local_bh_enable();
+
+	return found;
+}
+
 static void cpts_process_events(struct cpts *cpts)
 {
 	struct list_head *this, *next;
@@ -318,6 +378,7 @@ static void cpts_process_events(struct cpts *cpts)
 	LIST_HEAD(events_free);
 	unsigned long flags;
 	LIST_HEAD(events);
+	int type;
 
 	spin_lock_irqsave(&cpts->lock, flags);
 	list_splice_init(&cpts->events, &events);
@@ -325,8 +386,18 @@ static void cpts_process_events(struct cpts *cpts)
 
 	list_for_each_safe(this, next, &events) {
 		event = list_entry(this, struct cpts_event, list);
-		if (cpts_match_tx_ts(cpts, event) ||
-		    time_after(jiffies, event->tmo)) {
+		type = event_type(event);
+
+		if (type == CPTS_EV_TX &&
+		    (cpts_match_tx_ts(cpts, event) ||
+		     time_after(jiffies, event->tmo))) {
+			list_del_init(&event->list);
+			list_add(&event->list, &events_free);
+		}
+
+		if (type == CPTS_EV_RX &&
+		    (cpts_match_rx_ts(cpts, event) ||
+		     time_after(jiffies, event->tmo))) {
 			list_del_init(&event->list);
 			list_add(&event->list, &events_free);
 		}
@@ -422,64 +493,27 @@ static int cpts_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
 	return 1;
 }
 
-static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb,
-			int ev_type, u32 skb_mtype_seqid)
-{
-	struct list_head *this, *next;
-	struct cpts_event *event;
-	unsigned long flags;
-	u32 mtype_seqid;
-	u64 ns = 0;
-
-	cpts_fifo_read(cpts, -1);
-	spin_lock_irqsave(&cpts->lock, flags);
-	list_for_each_safe(this, next, &cpts->events) {
-		event = list_entry(this, struct cpts_event, list);
-		if (event_expired(event)) {
-			list_del_init(&event->list);
-			list_add(&event->list, &cpts->pool);
-			continue;
-		}
-
-		mtype_seqid = event->high &
-			      ((MESSAGE_TYPE_MASK << MESSAGE_TYPE_SHIFT) |
-			       (SEQUENCE_ID_MASK << SEQUENCE_ID_SHIFT) |
-			       (EVENT_TYPE_MASK << EVENT_TYPE_SHIFT));
-
-		if (mtype_seqid == skb_mtype_seqid) {
-			ns = event->timestamp;
-			list_del_init(&event->list);
-			list_add(&event->list, &cpts->pool);
-			break;
-		}
-	}
-	spin_unlock_irqrestore(&cpts->lock, flags);
-
-	return ns;
-}
-
-void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
+int cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 {
 	struct cpts_skb_cb_data *skb_cb = (struct cpts_skb_cb_data *)skb->cb;
-	struct skb_shared_hwtstamps *ssh;
 	int ret;
-	u64 ns;
 
 	ret = cpts_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
 	if (!ret)
-		return;
+		return 0;
 
 	skb_cb->skb_mtype_seqid |= (CPTS_EV_RX << EVENT_TYPE_SHIFT);
 
 	dev_dbg(cpts->dev, "%s mtype seqid %08x\n",
 		__func__, skb_cb->skb_mtype_seqid);
 
-	ns = cpts_find_ts(cpts, skb, CPTS_EV_RX, skb_cb->skb_mtype_seqid);
-	if (!ns)
-		return;
-	ssh = skb_hwtstamps(skb);
-	memset(ssh, 0, sizeof(*ssh));
-	ssh->hwtstamp = ns_to_ktime(ns);
+	/* Always defer RX TS processing to PTP worker */
+	/* get the timestamp for timeouts */
+	skb_cb->tmo = jiffies + msecs_to_jiffies(CPTS_SKB_RX_TX_TMO);
+	skb_queue_tail(&cpts->rxq, skb);
+	ptp_schedule_worker(cpts->clock, 0);
+
+	return 1;
 }
 EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
 
@@ -514,6 +548,7 @@ int cpts_register(struct cpts *cpts)
 	int err, i;
 
 	skb_queue_head_init(&cpts->txq);
+	skb_queue_head_init(&cpts->rxq);
 	INIT_LIST_HEAD(&cpts->events);
 	INIT_LIST_HEAD(&cpts->pool);
 	for (i = 0; i < CPTS_MAX_EVENTS; i++)
@@ -556,6 +591,7 @@ void cpts_unregister(struct cpts *cpts)
 
 	/* Drop all packet */
 	skb_queue_purge(&cpts->txq);
+	skb_queue_purge(&cpts->rxq);
 
 	clk_disable(cpts->refclk);
 }
diff --git a/drivers/net/ethernet/ti/cpts.h b/drivers/net/ethernet/ti/cpts.h
index f16e14d67f5f..993b4cfa4e86 100644
--- a/drivers/net/ethernet/ti/cpts.h
+++ b/drivers/net/ethernet/ti/cpts.h
@@ -115,12 +115,13 @@ struct cpts {
 	struct cpts_event pool_data[CPTS_MAX_EVENTS];
 	unsigned long ov_check_period;
 	struct sk_buff_head txq;
+	struct sk_buff_head rxq;
 	u64 cur_timestamp;
 	u32 mult_new;
 	struct mutex ptp_clk_mutex; /* sync PTP interface and worker */
 };
 
-void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb);
+int cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb);
 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb);
 int cpts_register(struct cpts *cpts);
 void cpts_unregister(struct cpts *cpts);
-- 
2.17.1