net/macb: add TX checksum offload feature

Signed-off-by: NCyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb.c

@@ -1525,6 +1525,10 @@ static void macb_configure_dma(struct macb *bp)
 			dmacfg = GEM_BFINS(FBLDO, bp->dma_burst_length, dmacfg);
 		dmacfg |= GEM_BIT(TXPBMS) | GEM_BF(RXBMS, -1L);
 		dmacfg &= ~GEM_BIT(ENDIA);
+		if (bp->dev->features & NETIF_F_HW_CSUM)
+			dmacfg |= GEM_BIT(TXCOEN);
+		else
+			dmacfg &= ~GEM_BIT(TXCOEN);
 		netdev_dbg(bp->dev, "Cadence configure DMA with 0x%08x\n",
 			   dmacfg);
 		gem_writel(bp, DMACFG, dmacfg);
@@ -1925,6 +1929,27 @@ int macb_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 }
 EXPORT_SYMBOL_GPL(macb_ioctl);
 
+static int macb_set_features(struct net_device *netdev,
+			     netdev_features_t features)
+{
+	struct macb *bp = netdev_priv(netdev);
+	netdev_features_t changed = features ^ netdev->features;
+
+	/* TX checksum offload */
+	if ((changed & NETIF_F_HW_CSUM) && macb_is_gem(bp)) {
+		u32 dmacfg;
+
+		dmacfg = gem_readl(bp, DMACFG);
+		if (features & NETIF_F_HW_CSUM)
+			dmacfg |= GEM_BIT(TXCOEN);
+		else
+			dmacfg &= ~GEM_BIT(TXCOEN);
+		gem_writel(bp, DMACFG, dmacfg);
+	}
+
+	return 0;
+}
+
 static const struct net_device_ops macb_netdev_ops = {
 	.ndo_open		= macb_open,
 	.ndo_stop		= macb_close,
@@ -1938,6 +1963,7 @@ static const struct net_device_ops macb_netdev_ops = {
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	.ndo_poll_controller	= macb_poll_controller,
 #endif
+	.ndo_set_features	= macb_set_features,
 };
 
 #if defined(CONFIG_OF)
@@ -2122,6 +2148,9 @@ static int __init macb_probe(struct platform_device *pdev)
 
 	/* Set features */
 	dev->hw_features = NETIF_F_SG;
+	/* Checksum offload is only available on gem with packet buffer */
+	if (macb_is_gem(bp) && !(bp->caps & MACB_CAPS_FIFO_MODE))
+		dev->hw_features |= NETIF_F_HW_CSUM;
 	if (bp->caps & MACB_CAPS_SG_DISABLED)
 		dev->hw_features &= ~NETIF_F_SG;
 	dev->features = dev->hw_features;