dp83640: fix phy status frame event parsing

If two eternal time stamp events occur at nearly the same time, the
phyter will add an extra word into the status frame. This commit fixes
the parsing code to recognize and skip over the extra word.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>

drivers/net/phy/dp83640.c

@@ -543,11 +543,20 @@ static void recalibrate(struct dp83640_clock *clock)
 
 /* time stamping methods */
 
-static void decode_evnt(struct dp83640_private *dp83640,
-			struct phy_txts *phy_txts, u16 ests)
+static int decode_evnt(struct dp83640_private *dp83640,
+		       void *data, u16 ests)
 {
+	struct phy_txts *phy_txts;
 	struct ptp_clock_event event;
 	int words = (ests >> EVNT_TS_LEN_SHIFT) & EVNT_TS_LEN_MASK;
+	u16 ext_status = 0;
+
+	if (ests & MULT_EVNT) {
+		ext_status = *(u16 *) data;
+		data += sizeof(ext_status);
+	}
+
+	phy_txts = data;
 
 	switch (words) { /* fall through in every case */
 	case 3:
@@ -565,6 +574,9 @@ static void decode_evnt(struct dp83640_private *dp83640,
 	event.timestamp = phy2txts(&dp83640->edata);
 
 	ptp_clock_event(dp83640->clock->ptp_clock, &event);
+
+	words = ext_status ? words + 2 : words + 1;
+	return words * sizeof(u16);
 }
 
 static void decode_rxts(struct dp83640_private *dp83640,
@@ -643,9 +655,7 @@ static void decode_status_frame(struct dp83640_private *dp83640,
 
 		} else if (PSF_EVNT == type && len >= sizeof(*phy_txts)) {
 
-			phy_txts = (struct phy_txts *) ptr;
-			decode_evnt(dp83640, phy_txts, ests);
-			size = sizeof(*phy_txts);
+			size = decode_evnt(dp83640, ptr, ests);
 
 		} else {
 			size = 0;