e100: Support RXFCS feature flag.

This allows e100 to be configured to append the
Ethernet FCS to the skb.

Useful for sniffing networks.
Signed-off-by: NBen Greear <greearb@candelatech.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e100.c

@@ -1075,7 +1075,7 @@ static void e100_get_defaults(struct nic *nic)
 	/* Template for a freshly allocated RFD */
 	nic->blank_rfd.command = 0;
 	nic->blank_rfd.rbd = cpu_to_le32(0xFFFFFFFF);
-	nic->blank_rfd.size = cpu_to_le16(VLAN_ETH_FRAME_LEN);
+	nic->blank_rfd.size = cpu_to_le16(VLAN_ETH_FRAME_LEN + ETH_FCS_LEN);
 
 	/* MII setup */
 	nic->mii.phy_id_mask = 0x1F;
@@ -1089,6 +1089,7 @@ static void e100_configure(struct nic *nic, struct cb *cb, struct sk_buff *skb)
 {
 	struct config *config = &cb->u.config;
 	u8 *c = (u8 *)config;
+	struct net_device *netdev = nic->netdev;
 
 	cb->command = cpu_to_le16(cb_config);
 
@@ -1132,6 +1133,9 @@ static void e100_configure(struct nic *nic, struct cb *cb, struct sk_buff *skb)
 		config->promiscuous_mode = 0x1;		/* 1=on, 0=off */
 	}
 
+	if (unlikely(netdev->features & NETIF_F_RXFCS))
+		config->rx_crc_transfer = 0x1;	/* 1=save, 0=discard */
+
 	if (nic->flags & multicast_all)
 		config->multicast_all = 0x1;		/* 1=accept, 0=no */
 
@@ -1881,7 +1885,7 @@ static inline void e100_start_receiver(struct nic *nic, struct rx *rx)
 	}
 }
 
-#define RFD_BUF_LEN (sizeof(struct rfd) + VLAN_ETH_FRAME_LEN)
+#define RFD_BUF_LEN (sizeof(struct rfd) + VLAN_ETH_FRAME_LEN + ETH_FCS_LEN)
 static int e100_rx_alloc_skb(struct nic *nic, struct rx *rx)
 {
 	if (!(rx->skb = netdev_alloc_skb_ip_align(nic->netdev, RFD_BUF_LEN)))
@@ -1919,6 +1923,7 @@ static int e100_rx_indicate(struct nic *nic, struct rx *rx,
 	struct sk_buff *skb = rx->skb;
 	struct rfd *rfd = (struct rfd *)skb->data;
 	u16 rfd_status, actual_size;
+	u16 fcs_pad = 0;
 
 	if (unlikely(work_done && *work_done >= work_to_do))
 		return -EAGAIN;
@@ -1951,6 +1956,8 @@ static int e100_rx_indicate(struct nic *nic, struct rx *rx,
 	}
 
 	/* Get actual data size */
+	if (unlikely(dev->features & NETIF_F_RXFCS))
+		fcs_pad = 4;
 	actual_size = le16_to_cpu(rfd->actual_size) & 0x3FFF;
 	if (unlikely(actual_size > RFD_BUF_LEN - sizeof(struct rfd)))
 		actual_size = RFD_BUF_LEN - sizeof(struct rfd);
@@ -1980,13 +1987,13 @@ static int e100_rx_indicate(struct nic *nic, struct rx *rx,
 	if (unlikely(!(rfd_status & cb_ok))) {
 		/* Don't indicate if hardware indicates errors */
 		dev_kfree_skb_any(skb);
-	} else if (actual_size > ETH_DATA_LEN + VLAN_ETH_HLEN) {
+	} else if (actual_size > ETH_DATA_LEN + VLAN_ETH_HLEN + fcs_pad) {
 		/* Don't indicate oversized frames */
 		nic->rx_over_length_errors++;
 		dev_kfree_skb_any(skb);
 	} else {
 		dev->stats.rx_packets++;
-		dev->stats.rx_bytes += actual_size;
+		dev->stats.rx_bytes += (actual_size - fcs_pad);
 		netif_receive_skb(skb);
 		if (work_done)
 			(*work_done)++;
@@ -2058,7 +2065,8 @@ static void e100_rx_clean(struct nic *nic, unsigned int *work_done,
 		pci_dma_sync_single_for_device(nic->pdev,
 			old_before_last_rx->dma_addr, sizeof(struct rfd),
 			PCI_DMA_BIDIRECTIONAL);
-		old_before_last_rfd->size = cpu_to_le16(VLAN_ETH_FRAME_LEN);
+		old_before_last_rfd->size = cpu_to_le16(VLAN_ETH_FRAME_LEN
+							+ ETH_FCS_LEN);
 		pci_dma_sync_single_for_device(nic->pdev,
 			old_before_last_rx->dma_addr, sizeof(struct rfd),
 			PCI_DMA_BIDIRECTIONAL);
@@ -2729,6 +2737,20 @@ static int e100_close(struct net_device *netdev)
 	return 0;
 }
 
+static int e100_set_features(struct net_device *netdev,
+			     netdev_features_t features)
+{
+	struct nic *nic = netdev_priv(netdev);
+	netdev_features_t changed = features ^ netdev->features;
+
+	if (!(changed & (NETIF_F_RXFCS)))
+		return 0;
+
+	netdev->features = features;
+	e100_exec_cb(nic, NULL, e100_configure);
+	return 0;
+}
+
 static const struct net_device_ops e100_netdev_ops = {
 	.ndo_open		= e100_open,
 	.ndo_stop		= e100_close,
@@ -2742,6 +2764,7 @@ static const struct net_device_ops e100_netdev_ops = {
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	.ndo_poll_controller	= e100_netpoll,
 #endif
+	.ndo_set_features	= e100_set_features,
 };
 
 static int __devinit e100_probe(struct pci_dev *pdev,
@@ -2754,6 +2777,8 @@ static int __devinit e100_probe(struct pci_dev *pdev,
 	if (!(netdev = alloc_etherdev(sizeof(struct nic))))
 		return -ENOMEM;
 
+	netdev->hw_features |= NETIF_F_RXFCS;
+
 	netdev->netdev_ops = &e100_netdev_ops;
 	SET_ETHTOOL_OPS(netdev, &e100_ethtool_ops);
 	netdev->watchdog_timeo = E100_WATCHDOG_PERIOD;