net: ll_temac: fix checksum offload logic

The current checksum offload code does not work and this corrects
that functionality. It also updates the interrupt coallescing
initialization so than there are fewer interrupts and performance
is increased.

Signed-off-by: Brian Hill <brian.hill@xilinx.com>
Signed-off-by: John Linn <john.linn@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ll_temac_main.c b/drivers/net/ll_temac_main.c
index 1bb6e60..fbd07de 100644
--- a/drivers/net/ll_temac_main.c
+++ b/drivers/net/ll_temac_main.c
@@ -245,7 +245,7 @@
 					  CHNL_CTRL_IRQ_COAL_EN);
 	/* 0x10220483 */
 	/* 0x00100483 */
-	lp->dma_out(lp, RX_CHNL_CTRL, 0xff010000 |
+	lp->dma_out(lp, RX_CHNL_CTRL, 0xff070000 |
 					  CHNL_CTRL_IRQ_EN |
 					  CHNL_CTRL_IRQ_DLY_EN |
 					  CHNL_CTRL_IRQ_COAL_EN |
@@ -574,6 +574,10 @@
 		if (cur_p->app4)
 			dev_kfree_skb_irq((struct sk_buff *)cur_p->app4);
 		cur_p->app0 = 0;
+		cur_p->app1 = 0;
+		cur_p->app2 = 0;
+		cur_p->app3 = 0;
+		cur_p->app4 = 0;
 
 		ndev->stats.tx_packets++;
 		ndev->stats.tx_bytes += cur_p->len;
@@ -589,6 +593,29 @@
 	netif_wake_queue(ndev);
 }
 
+static inline int temac_check_tx_bd_space(struct temac_local *lp, int num_frag)
+{
+	struct cdmac_bd *cur_p;
+	int tail;
+
+	tail = lp->tx_bd_tail;
+	cur_p = &lp->tx_bd_v[tail];
+
+	do {
+		if (cur_p->app0)
+			return NETDEV_TX_BUSY;
+
+		tail++;
+		if (tail >= TX_BD_NUM)
+			tail = 0;
+
+		cur_p = &lp->tx_bd_v[tail];
+		num_frag--;
+	} while (num_frag >= 0);
+
+	return 0;
+}
+
 static int temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
 	struct temac_local *lp = netdev_priv(ndev);
@@ -603,7 +630,7 @@
 	start_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
 	cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
 
-	if (cur_p->app0 & STS_CTRL_APP0_CMPLT) {
+	if (temac_check_tx_bd_space(lp, num_frag)) {
 		if (!netif_queue_stopped(ndev)) {
 			netif_stop_queue(ndev);
 			return NETDEV_TX_BUSY;
@@ -613,29 +640,14 @@
 
 	cur_p->app0 = 0;
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		const struct iphdr *ip = ip_hdr(skb);
-		int length = 0, start = 0, insert = 0;
+		unsigned int csum_start_off = skb_transport_offset(skb);
+		unsigned int csum_index_off = csum_start_off + skb->csum_offset;
 
-		switch (ip->protocol) {
-		case IPPROTO_TCP:
-			start = sizeof(struct iphdr) + ETH_HLEN;
-			insert = sizeof(struct iphdr) + ETH_HLEN + 16;
-			length = ip->tot_len - sizeof(struct iphdr);
-			break;
-		case IPPROTO_UDP:
-			start = sizeof(struct iphdr) + ETH_HLEN;
-			insert = sizeof(struct iphdr) + ETH_HLEN + 6;
-			length = ip->tot_len - sizeof(struct iphdr);
-			break;
-		default:
-			break;
-		}
-		cur_p->app1 = ((start << 16) | insert);
-		cur_p->app2 = csum_tcpudp_magic(ip->saddr, ip->daddr,
-						length, ip->protocol, 0);
-		skb->data[insert] = 0;
-		skb->data[insert + 1] = 0;
+		cur_p->app0 |= 1; /* TX Checksum Enabled */
+		cur_p->app1 = (csum_start_off << 16) | csum_index_off;
+		cur_p->app2 = 0;  /* initial checksum seed */
 	}
+
 	cur_p->app0 |= STS_CTRL_APP0_SOP;
 	cur_p->len = skb_headlen(skb);
 	cur_p->phys = dma_map_single(ndev->dev.parent, skb->data, skb->len,
@@ -699,6 +711,15 @@
 		skb->protocol = eth_type_trans(skb, ndev);
 		skb->ip_summed = CHECKSUM_NONE;
 
+		/* if we're doing rx csum offload, set it up */
+		if (((lp->temac_features & TEMAC_FEATURE_RX_CSUM) != 0) &&
+			(skb->protocol == __constant_htons(ETH_P_IP)) &&
+			(skb->len > 64)) {
+
+			skb->csum = cur_p->app3 & 0xFFFF;
+			skb->ip_summed = CHECKSUM_COMPLETE;
+		}
+
 		netif_rx(skb);
 
 		ndev->stats.rx_packets++;
@@ -883,6 +904,7 @@
 	struct temac_local *lp;
 	struct net_device *ndev;
 	const void *addr;
+	__be32 *p;
 	int size, rc = 0;
 
 	/* Init network device structure */
@@ -926,6 +948,18 @@
 		goto nodev;
 	}
 
+	/* Setup checksum offload, but default to off if not specified */
+	lp->temac_features = 0;
+	p = (__be32 *)of_get_property(op->dev.of_node, "xlnx,txcsum", NULL);
+	if (p && be32_to_cpu(*p)) {
+		lp->temac_features |= TEMAC_FEATURE_TX_CSUM;
+		/* Can checksum TCP/UDP over IPv4. */
+		ndev->features |= NETIF_F_IP_CSUM;
+	}
+	p = (__be32 *)of_get_property(op->dev.of_node, "xlnx,rxcsum", NULL);
+	if (p && be32_to_cpu(*p))
+		lp->temac_features |= TEMAC_FEATURE_RX_CSUM;
+
 	/* Find the DMA node, map the DMA registers, and decode the DMA IRQs */
 	np = of_parse_phandle(op->node, "llink-connected", 0);
 	if (!np) {