can: sja1000: fix network statistics update

The member "tx_bytes" of "struct net_device_stats" should be
incremented when the interrupt is done and an "arbitration
lost error" is a TX error and the statistics should be updated
accordingly.
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/can/sja1000/sja1000.c

@@ -242,7 +242,6 @@ static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
 					    struct net_device *dev)
 {
 	struct sja1000_priv *priv = netdev_priv(dev);
-	struct net_device_stats *stats = &dev->stats;
 	struct can_frame *cf = (struct can_frame *)skb->data;
 	uint8_t fi;
 	uint8_t dlc;
@@ -276,7 +275,6 @@ static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
 	for (i = 0; i < dlc; i++)
 		priv->write_reg(priv, dreg++, cf->data[i]);
 
-	stats->tx_bytes += dlc;
 	dev->trans_start = jiffies;
 
 	can_put_echo_skb(skb, dev, 0);
@@ -427,7 +425,7 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 		dev_dbg(dev->dev.parent, "arbitration lost interrupt\n");
 		alc = priv->read_reg(priv, REG_ALC);
 		priv->can.can_stats.arbitration_lost++;
-		stats->rx_errors++;
+		stats->tx_errors++;
 		cf->can_id |= CAN_ERR_LOSTARB;
 		cf->data[0] = alc & 0x1f;
 	}
@@ -484,6 +482,7 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id)
 
 		if (isrc & IRQ_TI) {
 			/* transmission complete interrupt */
+			stats->tx_bytes += priv->read_reg(priv, REG_FI) & 0xf;
 			stats->tx_packets++;
 			can_get_echo_skb(dev, 0);
 			netif_wake_queue(dev);