[PATCH net-next v4 05/10] net: ethernet: ti: cpts: optimize packet to event matching

[Grygorii Strashko]

Now the CPTS driver performs packet (skb) parsing every time when it needs
to match packet to CPTS event (including ptp_classify_raw() calls).

This patch optimizes matching process by parsing packet only once upon
arrival and stores PTP specific data in skb->cb using the same fromat as in
CPTS HW event. As result, all future matching reduces to comparing two u32
values.

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
---
 drivers/net/ethernet/ti/cpts.c | 91 ++++++++++++++++++++++------------
 1 file changed, 58 insertions(+), 33 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index 1f738bb3df74..6efb809d58ed 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -23,15 +23,13 @@
 #define CPTS_SKB_TX_WORK_TIMEOUT 1 /* jiffies */
 
 struct cpts_skb_cb_data {
+	u32 skb_mtype_seqid;
 	unsigned long tmo;
 };
 
 #define cpts_read32(c, r)	readl_relaxed(&c->reg->r)
 #define cpts_write32(c, v, r)	writel_relaxed(v, &c->reg->r)
 
-static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
-		      u16 ts_seqid, u8 ts_msgtype);
-
 static int event_expired(struct cpts_event *event)
 {
 	return time_after(jiffies, event->tmo);
@@ -97,29 +95,29 @@ static void cpts_purge_txq(struct cpts *cpts)
 static bool cpts_match_tx_ts(struct cpts *cpts, struct cpts_event *event)
 {
 	struct sk_buff *skb, *tmp;
-	u16 seqid;
-	u8 mtype;
 	bool found = false;
+	u32 mtype_seqid;
 
-	mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
-	seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
+	mtype_seqid = event->high &
+		      ((MESSAGE_TYPE_MASK << MESSAGE_TYPE_SHIFT) |
+		       (SEQUENCE_ID_MASK << SEQUENCE_ID_SHIFT) |
+		       (EVENT_TYPE_MASK << EVENT_TYPE_SHIFT));
 
 	/* no need to grab txq.lock as access is always done under cpts->lock */
 	skb_queue_walk_safe(&cpts->txq, skb, tmp) {
 		struct skb_shared_hwtstamps ssh;
-		unsigned int class = ptp_classify_raw(skb);
 		struct cpts_skb_cb_data *skb_cb =
 					(struct cpts_skb_cb_data *)skb->cb;
 
-		if (cpts_match(skb, class, seqid, mtype)) {
+		if (mtype_seqid == skb_cb->skb_mtype_seqid) {
 			memset(&ssh, 0, sizeof(ssh));
 			ssh.hwtstamp = ns_to_ktime(event->timestamp);
 			skb_tstamp_tx(skb, &ssh);
 			found = true;
 			__skb_unlink(skb, &cpts->txq);
 			dev_consume_skb_any(skb);
-			dev_dbg(cpts->dev, "match tx timestamp mtype %u seqid %04x\n",
-				mtype, seqid);
+			dev_dbg(cpts->dev, "match tx timestamp mtype_seqid %08x\n",
+				mtype_seqid);
 			break;
 		}
 
@@ -338,12 +336,15 @@ static const struct ptp_clock_info cpts_info = {
 	.do_aux_work	= cpts_overflow_check,
 };
 
-static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
-		      u16 ts_seqid, u8 ts_msgtype)
+static int cpts_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
 {
-	u16 *seqid;
-	unsigned int offset = 0;
+	unsigned int ptp_class = ptp_classify_raw(skb);
 	u8 *msgtype, *data = skb->data;
+	unsigned int offset = 0;
+	u16 *seqid;
+
+	if (ptp_class == PTP_CLASS_NONE)
+		return 0;
 
 	if (ptp_class & PTP_CLASS_VLAN)
 		offset += VLAN_HLEN;
@@ -371,22 +372,20 @@ static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
 		msgtype = data + offset;
 
 	seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
+	*mtype_seqid = (*msgtype & MESSAGE_TYPE_MASK) << MESSAGE_TYPE_SHIFT;
+	*mtype_seqid |= (ntohs(*seqid) & SEQUENCE_ID_MASK) << SEQUENCE_ID_SHIFT;
 
-	return (ts_msgtype == (*msgtype & 0xf) && ts_seqid == ntohs(*seqid));
+	return 1;
 }
 
-static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
+static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb,
+			int ev_type, u32 skb_mtype_seqid)
 {
-	u64 ns = 0;
-	struct cpts_event *event;
 	struct list_head *this, *next;
-	unsigned int class = ptp_classify_raw(skb);
+	struct cpts_event *event;
 	unsigned long flags;
-	u16 seqid;
-	u8 mtype;
-
-	if (class == PTP_CLASS_NONE)
-		return 0;
+	u32 mtype_seqid;
+	u64 ns = 0;
 
 	spin_lock_irqsave(&cpts->lock, flags);
 	cpts_fifo_read(cpts, -1);
@@ -397,10 +396,13 @@ static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
 			list_add(&event->list, &cpts->pool);
 			continue;
 		}
-		mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
-		seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
-		if (ev_type == event_type(event) &&
-		    cpts_match(skb, class, seqid, mtype)) {
+
+		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);
@@ -427,10 +429,21 @@ static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
 
 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 {
-	u64 ns;
+	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;
+
+	skb_cb->skb_mtype_seqid |= (CPTS_EV_RX << EVENT_TYPE_SHIFT);
 
-	ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
+	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);
@@ -441,12 +454,24 @@ EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
 
 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 {
-	u64 ns;
+	struct cpts_skb_cb_data *skb_cb = (struct cpts_skb_cb_data *)skb->cb;
 	struct skb_shared_hwtstamps ssh;
+	int ret;
+	u64 ns;
 
 	if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
 		return;
-	ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
+
+	ret = cpts_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
+	if (!ret)
+		return;
+
+	skb_cb->skb_mtype_seqid |= (CPTS_EV_TX << 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_TX, skb_cb->skb_mtype_seqid);
 	if (!ns)
 		return;
 	memset(&ssh, 0, sizeof(ssh));
-- 
2.17.1