dsa: mv88x6xxx: Refactor getting a single statistic

Move the code to retrieve a statistics counter into a function of its
own, so it can later be reused.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx.c

@@ -681,52 +681,61 @@ static void _mv88e6xxx_get_strings(struct dsa_switch *ds,
 	}
 }
 
-static void _mv88e6xxx_get_ethtool_stats(struct dsa_switch *ds,
-					 int nr_stats,
+static uint64_t _mv88e6xxx_get_ethtool_stat(struct dsa_switch *ds,
+					    int stat,
 					    struct mv88e6xxx_hw_stat *stats,
-					 int port, uint64_t *data)
+					    int port)
 {
-	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
-	int ret;
-	int i;
-
-	mutex_lock(&ps->smi_mutex);
-
-	ret = _mv88e6xxx_stats_snapshot(ds, port);
-	if (ret < 0) {
-		mutex_unlock(&ps->smi_mutex);
-		return;
-	}
-
-	/* Read each of the counters. */
-	for (i = 0; i < nr_stats; i++) {
-		struct mv88e6xxx_hw_stat *s = stats + i;
+	struct mv88e6xxx_hw_stat *s = stats + stat;
 	u32 low;
 	u32 high = 0;
+	int ret;
+	u64 value;
 
 	if (s->reg >= 0x100) {
 		ret = _mv88e6xxx_reg_read(ds, REG_PORT(port),
 					  s->reg - 0x100);
 		if (ret < 0)
-				goto error;
+			return UINT64_MAX;
+
 		low = ret;
 		if (s->sizeof_stat == 4) {
 			ret = _mv88e6xxx_reg_read(ds, REG_PORT(port),
 						  s->reg - 0x100 + 1);
 			if (ret < 0)
-					goto error;
+				return UINT64_MAX;
 			high = ret;
 		}
-			data[i] = (((u64)high) << 16) | low;
-			continue;
-		}
+	} else {
 		_mv88e6xxx_stats_read(ds, s->reg, &low);
 		if (s->sizeof_stat == 8)
 			_mv88e6xxx_stats_read(ds, s->reg + 1, &high);
+	}
+	value = (((u64)high) << 16) | low;
+	return value;
+}
+
+static void _mv88e6xxx_get_ethtool_stats(struct dsa_switch *ds,
+					 int nr_stats,
+					 struct mv88e6xxx_hw_stat *stats,
+					 int port, uint64_t *data)
+{
+	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+	int ret;
+	int i;
+
+	mutex_lock(&ps->smi_mutex);
 
-		data[i] = (((u64)high) << 32) | low;
+	ret = _mv88e6xxx_stats_snapshot(ds, port);
+	if (ret < 0) {
+		mutex_unlock(&ps->smi_mutex);
+		return;
 	}
-error:
+
+	/* Read each of the counters. */
+	for (i = 0; i < nr_stats; i++)
+		data[i] = _mv88e6xxx_get_ethtool_stat(ds, i, stats, port);
+
 	mutex_unlock(&ps->smi_mutex);
 }
 

drivers/net/dsa/mv88e6xxx.h

@@ -11,6 +11,10 @@
 #ifndef __MV88E6XXX_H
 #define __MV88E6XXX_H
 
+#ifndef UINT64_MAX
+#define UINT64_MAX		(u64)(~((u64)0))
+#endif
+
 #define SMI_CMD			0x00
 #define SMI_CMD_BUSY		BIT(15)
 #define SMI_CMD_CLAUSE_22	BIT(12)