ethoc: limit the number of buffers to 128

Only 128 buffer descriptors are supported in the core. Limit the
number in case we have more memory.
Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethoc.c

@@ -662,8 +662,8 @@ static int ethoc_open(struct net_device *dev)
 	if (ret)
 		return ret;
 
-	/* calculate the number of TX/RX buffers */
-	num_bd = (dev->mem_end - dev->mem_start + 1) / ETHOC_BUFSIZ;
+	/* calculate the number of TX/RX buffers, maximum 128 supported */
+	num_bd = min(128, (dev->mem_end - dev->mem_start + 1) / ETHOC_BUFSIZ);
 	priv->num_tx = max(min_tx, num_bd / 4);
 	priv->num_rx = num_bd - priv->num_tx;
 	ethoc_write(priv, TX_BD_NUM, priv->num_tx);