net: systemport: Dynamically allocate number of TX rings

In preparation for adding SYSTEMPORT Lite, which has twice as less transmit
queues than SYSTEMPORT make sure we do allocate TX rings based on the
systemport,txq property to get an appropriate memory footprint.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bcmsysport.c

@@ -1752,6 +1752,10 @@ static int bcm_sysport_probe(struct platform_device *pdev)
 	if (of_property_read_u32(dn, "systemport,num-rxq", &rxq))
 		rxq = 1;
 
+	/* Sanity check the number of transmit queues */
+	if (!txq || txq > TDMA_NUM_RINGS)
+		return -EINVAL;
+
 	dev = alloc_etherdev_mqs(sizeof(*priv), txq, rxq);
 	if (!dev)
 		return -ENOMEM;
@@ -1759,6 +1763,13 @@ static int bcm_sysport_probe(struct platform_device *pdev)
 	/* Initialize private members */
 	priv = netdev_priv(dev);
 
+	/* Allocate number of TX rings */
+	priv->tx_rings = devm_kcalloc(&pdev->dev, txq,
+				      sizeof(struct bcm_sysport_tx_ring),
+				      GFP_KERNEL);
+	if (!priv->tx_rings)
+		return -ENOMEM;
+
 	priv->irq0 = platform_get_irq(pdev, 0);
 	priv->irq1 = platform_get_irq(pdev, 1);
 	priv->wol_irq = platform_get_irq(pdev, 2);

drivers/net/ethernet/broadcom/bcmsysport.h

@@ -659,7 +659,7 @@ struct bcm_sysport_priv {
 	int			wol_irq;
 
 	/* Transmit rings */
-	struct bcm_sysport_tx_ring tx_rings[TDMA_NUM_RINGS];
+	struct bcm_sysport_tx_ring *tx_rings;
 
 	/* Receive queue */
 	void __iomem		*rx_bds;