[LEDE-DEV] [RFC] AR8327 driver: implementing get_port_stats function

[Daniel Gonzalez Cabanelas]

Currently the switch LED trigger only shows link status, but not traffic activity by blinking
the LEDs on the AR8316/AR8327 switch. It turns out that the get_port_stats is missing.

I've made this patch, which works ok. But I'm not sure if there is any reason to not implement this 
function. And probably the function ar8xxx_sw_get_port_stats can be improved.

There are a few boards with an  AR8316/AR8327 switch that need this trigger, usually on the WAN port.
As said without get_port_stats the light stays always fixed, like if there wasn't traffic activity. We can use 
the netdev trigger but then the light is always on even when the cable is unplugged, and there isn't the
possibility of using a second LED trigger on the same port for indicating a reduced link speed.

diff --git a/target/linux/generic/files/drivers/net/phy/ar8216.c b/target/linux/generic/files/drivers/net/phy/ar8216.c
index 37877d5..ffaa77e 100644
--- a/target/linux/generic/files/drivers/net/phy/ar8216.c
+++ b/target/linux/generic/files/drivers/net/phy/ar8216.c
@@ -1001,6 +1001,41 @@ ar8xxx_sw_get_port_link(struct switch_dev *dev, int port,
 	return 0;
 }
 
+int
+ar8xxx_sw_get_port_stats(struct switch_dev *dev, int port,
+		       struct switch_port_stats *stats)
+{
+	struct ar8xxx_priv *priv = swdev_to_ar8xxx(dev);
+	const struct ar8xxx_chip *chip = priv->chip;
+	u64 *mib_stats, mib_data;
+	const char *mib_name;
+	int i;
+
+	if (!ar8xxx_has_mib_counters(priv))
+		return -EOPNOTSUPP;
+
+	if (port >= dev->ports)
+		return -EINVAL;
+
+	mutex_lock(&priv->mib_lock);
+
+	ar8xxx_mib_fetch_port_stat(priv, port, false);
+
+	mib_stats = &priv->mib_stats[port * chip->num_mibs];
+	for (i = 0; i < chip->num_mibs; i++) {
+		mib_name = chip->mib_decs[i].name;
+		mib_data = mib_stats[i];
+		if (!strcmp(mib_name, "TxByte"))
+			stats->tx_bytes = mib_data;
+		if (!strcmp(mib_name, "RxGoodByte"))
+			stats->rx_bytes = mib_data;
+	}
+
+	mutex_unlock(&priv->mib_lock);
+
+	return 0;
+}
+
 static int
 ar8xxx_sw_get_ports(struct switch_dev *dev, struct switch_val *val)
 {
@@ -1696,6 +1731,7 @@ static const struct switch_dev_ops ar8xxx_sw_ops = {
 	.apply_config = ar8xxx_sw_hw_apply,
 	.reset_switch = ar8xxx_sw_reset_switch,
 	.get_port_link = ar8xxx_sw_get_port_link,
+	.get_port_stats = ar8xxx_sw_get_port_stats,
 };
 
 static const struct ar8xxx_chip ar8216_chip = {
diff --git a/target/linux/generic/files/drivers/net/phy/ar8216.h b/target/linux/generic/files/drivers/net/phy/ar8216.h
index d9508b9..8b05cf3 100644
--- a/target/linux/generic/files/drivers/net/phy/ar8216.h
+++ b/target/linux/generic/files/drivers/net/phy/ar8216.h
@@ -538,6 +538,9 @@ int
 ar8xxx_sw_get_port_link(struct switch_dev *dev, int port,
 			struct switch_port_link *link);
 int
+ar8xxx_sw_get_port_stats(struct switch_dev *dev,
+		       int port, struct switch_port_stats *stats);
+int
 ar8xxx_sw_set_port_reset_mib(struct switch_dev *dev,
                              const struct switch_attr *attr,
                              struct switch_val *val);
diff --git a/target/linux/generic/files/drivers/net/phy/ar8327.c b/target/linux/generic/files/drivers/net/phy/ar8327.c
index 9b40cd7..e82563f 100644
--- a/target/linux/generic/files/drivers/net/phy/ar8327.c
+++ b/target/linux/generic/files/drivers/net/phy/ar8327.c
@@ -1372,6 +1372,7 @@ static const struct switch_dev_ops ar8327_sw_ops = {
 	.apply_config = ar8327_sw_hw_apply,
 	.reset_switch = ar8xxx_sw_reset_switch,
 	.get_port_link = ar8xxx_sw_get_port_link,
+	.get_port_stats = ar8xxx_sw_get_port_stats,
 };
 
 const struct ar8xxx_chip ar8327_chip = {