net: stmmac: separate the tas basetime calculation function

Separate the TAS basetime calculation function so that it can be
called by other functions.
Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -349,6 +349,9 @@ void stmmac_enable_rx_queue(struct stmmac_priv *priv, u32 queue);
 void stmmac_disable_tx_queue(struct stmmac_priv *priv, u32 queue);
 void stmmac_enable_tx_queue(struct stmmac_priv *priv, u32 queue);
 int stmmac_xsk_wakeup(struct net_device *dev, u32 queue, u32 flags);
+struct timespec64 stmmac_calc_tas_basetime(ktime_t old_base_time,
+					   ktime_t current_time,
+					   u64 cycle_time);
 
 #if IS_ENABLED(CONFIG_STMMAC_SELFTESTS)
 void stmmac_selftest_run(struct net_device *dev,

drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c

@@ -711,6 +711,29 @@ static int tc_setup_cls(struct stmmac_priv *priv,
 	return ret;
 }
 
+struct timespec64 stmmac_calc_tas_basetime(ktime_t old_base_time,
+					   ktime_t current_time,
+					   u64 cycle_time)
+{
+	struct timespec64 time;
+
+	if (ktime_after(old_base_time, current_time)) {
+		time = ktime_to_timespec64(old_base_time);
+	} else {
+		s64 n;
+		ktime_t base_time;
+
+		n = div64_s64(ktime_sub_ns(current_time, old_base_time),
+			      cycle_time);
+		base_time = ktime_add_ns(old_base_time,
+					 (n + 1) * cycle_time);
+
+		time = ktime_to_timespec64(base_time);
+	}
+
+	return time;
+}
+
 static int tc_setup_taprio(struct stmmac_priv *priv,
 			   struct tc_taprio_qopt_offload *qopt)
 {
@@ -814,19 +837,8 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 	/* Adjust for real system time */
 	priv->ptp_clock_ops.gettime64(&priv->ptp_clock_ops, &current_time);
 	current_time_ns = timespec64_to_ktime(current_time);
-	if (ktime_after(qopt->base_time, current_time_ns)) {
-		time = ktime_to_timespec64(qopt->base_time);
-	} else {
-		ktime_t base_time;
-		s64 n;
-
-		n = div64_s64(ktime_sub_ns(current_time_ns, qopt->base_time),
+	time = stmmac_calc_tas_basetime(qopt->base_time, current_time_ns,
 					qopt->cycle_time);
-		base_time = ktime_add_ns(qopt->base_time,
-					 (n + 1) * qopt->cycle_time);
-
-		time = ktime_to_timespec64(base_time);
-	}
 
 	priv->plat->est->btr[0] = (u32)time.tv_nsec;
 	priv->plat->est->btr[1] = (u32)time.tv_sec;