X-Git-Url: http://rtime.felk.cvut.cz/gitweb/socketcan-devel.git/blobdiff_plain/8318d250ba03d48ffd8f6709bb15e982a33cb06c..0c427ca3c10ee393978e87fb191bab55512480c4:/kernel/2.6/drivers/net/can/sja1000/sja1000.c

diff --git a/kernel/2.6/drivers/net/can/sja1000/sja1000.c b/kernel/2.6/drivers/net/can/sja1000/sja1000.c
index c868829..5ba308d 100644
--- a/kernel/2.6/drivers/net/can/sja1000/sja1000.c
+++ b/kernel/2.6/drivers/net/can/sja1000/sja1000.c
@@ -88,6 +88,27 @@ static struct can_bittiming_const sja1000_bittiming_const = {
 	.brp_inc = 1,
 };
 
+static void sja1000_write_cmdreg(struct sja1000_priv *priv, u8 val)
+{
+	/* the command register needs some locking on SMP systems */
+
+#ifdef CONFIG_SMP
+
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->cmdreg_lock, flags);
+	priv->write_reg(priv, REG_CMR, val);
+	priv->read_reg(priv, REG_SR);
+	spin_unlock_irqrestore(&priv->cmdreg_lock, flags);
+
+#else
+
+	/* write to the command register without locking */
+	priv->write_reg(priv, REG_CMR, val);
+
+#endif
+}
+
 static int sja1000_probe_chip(struct net_device *dev)
 {
 	struct sja1000_priv *priv = netdev_priv(dev);
@@ -305,7 +326,7 @@ static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
 
 	can_put_echo_skb(skb, dev, 0);
 
-	priv->write_reg(priv, REG_CMR, CMD_TR);
+	sja1000_write_cmdreg(priv, CMD_TR);
 
 	return NETDEV_TX_OK;
 }
@@ -358,7 +379,7 @@ static void sja1000_rx(struct net_device *dev)
 	cf->can_id = id;
 
 	/* release receive buffer */
-	priv->write_reg(priv, REG_CMR, CMD_RRB);
+	sja1000_write_cmdreg(priv, CMD_RRB);
 
 	netif_rx(skb);
 
@@ -393,7 +414,7 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 		stats->rx_over_errors++;
 		stats->rx_errors++;
-		priv->write_reg(priv, REG_CMR, CMD_CDO);	/* clear bit */
+		sja1000_write_cmdreg(priv, CMD_CDO);	/* clear bit */
 	}
 
 	if (isrc & IRQ_EI) {