--- drivers/net/can/sja1000/sja1000.c

+++ drivers/net/can/sja1000/sja1000.c

@@ -84,6 +84,20 @@ static struct can_bittiming_const sja100

.brp_inc = 1,

};

+static void sja1000_write_cmdreg(struct sja1000_priv *priv, u8 val)

+{

+ unsigned long flags;

+

+ /*

+ * The command register needs some locking and time to settle

+ * the write_reg() operation - especially on SMP systems.

+ */

+ 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);

+}

+

static int sja1000_probe_chip(struct net_device *dev)

{

struct sja1000_priv *priv = netdev_priv(dev);

@@ -279,7 +293,7 @@ static netdev_tx_t sja1000_start_xmit(st

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;

}

@@ -334,7 +348,7 @@ static void sja1000_rx(struct net_device

cf->data[i++] = 0;

/* release receive buffer */

- priv->write_reg(priv, REG_CMR, CMD_RRB);

+ sja1000_write_cmdreg(priv, CMD_RRB);

netif_rx(skb);

@@ -368,7 +382,7 @@ static int sja1000_err(struct net_device

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) {