[RFC,v2,2/2] net: Add support for NTB virtual ethernet device

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 0c2bd80..9bf8a71 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -178,6 +178,10 @@  config NETPOLL_TRAP
 config NET_POLL_CONTROLLER
 	def_bool NETPOLL
 
+config NTB_NETDEV
+	tristate "Virtual Ethernet over NTB"
+	depends on NTB
+
 config RIONET
 	tristate "RapidIO Ethernet over messaging driver support"
 	depends on RAPIDIO
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 3d375ca..9890148 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -69,3 +69,4 @@  obj-$(CONFIG_USB_IPHETH)        += usb/
 obj-$(CONFIG_USB_CDC_PHONET)   += usb/
 
 obj-$(CONFIG_HYPERV_NET) += hyperv/
+obj-$(CONFIG_NTB_NETDEV) += ntb_netdev.o
diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c
new file mode 100644
index 0000000..cb19a0b
--- /dev/null
+++ b/drivers/net/ntb_netdev.c
@@ -0,0 +1,417 @@ 
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ *   redistributing this file, you may do so under either license.
+ *
+ *   GPL LICENSE SUMMARY
+ *
+ *   Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of version 2 of the GNU General Public License as
+ *   published by the Free Software Foundation.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *   General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *   The full GNU General Public License is included in this distribution
+ *   in the file called LICENSE.GPL.
+ *
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copy
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel PCIe NTB Network Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason@intel.com>
+ */
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/ntb.h>
+
+#define NTB_NETDEV_VER	"0.5"
+
+MODULE_DESCRIPTION(KBUILD_MODNAME);
+MODULE_VERSION(NTB_NETDEV_VER);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Intel Corporation");
+
+struct ntb_netdev {
+	struct list_head list;
+	struct pci_dev *pdev;
+	struct net_device *ndev;
+	struct ntb_transport_qp *qp;
+};
+
+#define	NTB_TX_TIMEOUT_MS	1000
+#define	NTB_RXQ_SIZE		100
+
+static LIST_HEAD(dev_list);
+
+static void ntb_netdev_event_handler(void *data, int status)
+{
+	struct net_device *ndev = data;
+	struct ntb_netdev *dev = netdev_priv(ndev);
+
+	netdev_dbg(ndev, "Event %x, Link %x\n", status,
+		   ntb_transport_link_query(dev->qp));
+
+	/* Currently, only link status event is supported */
+	if (status)
+		netif_carrier_on(ndev);
+	else
+		netif_carrier_off(ndev);
+}
+
+static void ntb_netdev_rx_handler(void *data, struct ntb_transport_qp *qp)
+{
+	struct net_device *ndev = data;
+	struct sk_buff *skb;
+	int len, rc;
+
+	while ((skb = ntb_transport_rx_dequeue(qp, &len))) {
+		netdev_dbg(ndev, "%s: %d byte payload received\n", __func__,
+			   len);
+
+		skb_put(skb, len);
+		skb->protocol = eth_type_trans(skb, ndev);
+		skb->ip_summed = CHECKSUM_NONE;
+
+		if (netif_rx(skb) == NET_RX_DROP) {
+			ndev->stats.rx_errors++;
+			ndev->stats.rx_dropped++;
+		} else {
+			ndev->stats.rx_packets++;
+			ndev->stats.rx_bytes += len;
+		}
+
+		skb = netdev_alloc_skb(ndev, ndev->mtu + ETH_HLEN);
+		if (!skb) {
+			ndev->stats.rx_errors++;
+			ndev->stats.rx_frame_errors++;
+			break;
+		}
+
+		rc = ntb_transport_rx_enqueue(qp, skb, skb->data,
+					      ndev->mtu + ETH_HLEN);
+		if (rc) {
+			ndev->stats.rx_errors++;
+			ndev->stats.rx_fifo_errors++;
+			break;
+		}
+	}
+}
+
+static void ntb_netdev_tx_handler(void *data, struct ntb_transport_qp *qp)
+{
+	struct net_device *ndev = data;
+	struct sk_buff *skb;
+	int len;
+
+	while ((skb = ntb_transport_tx_dequeue(qp, &len))) {
+		ndev->stats.tx_packets++;
+		ndev->stats.tx_bytes += skb->len;
+		dev_kfree_skb(skb);
+	}
+
+	if (ndev && netif_queue_stopped(ndev))
+		netif_wake_queue(ndev);
+}
+
+static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
+					 struct net_device *ndev)
+{
+	struct ntb_netdev *dev = netdev_priv(ndev);
+	int rc;
+
+	netdev_dbg(ndev, "ntb_transport_tx_enqueue\n");
+
+	rc = ntb_transport_tx_enqueue(dev->qp, skb, skb->data, skb->len);
+	if (rc)
+		goto err;
+
+	return NETDEV_TX_OK;
+
+err:
+	ndev->stats.tx_dropped++;
+	ndev->stats.tx_errors++;
+	netif_stop_queue(ndev);
+	return NETDEV_TX_BUSY;
+}
+
+static int ntb_netdev_open(struct net_device *ndev)
+{
+	struct ntb_netdev *dev = netdev_priv(ndev);
+	struct sk_buff *skb;
+	int rc, i, len;
+
+	/* Add some empty rx bufs */
+	for (i = 0; i < NTB_RXQ_SIZE; i++) {
+		skb = netdev_alloc_skb(ndev, ndev->mtu + ETH_HLEN);
+		if (!skb) {
+			rc = -ENOMEM;
+			goto err;
+		}
+
+		rc = ntb_transport_rx_enqueue(dev->qp, skb, skb->data,
+					      ndev->mtu + ETH_HLEN);
+		if (rc == -EINVAL)
+			goto err;
+	}
+
+	netif_carrier_off(ndev);
+	ntb_transport_link_up(dev->qp);
+
+	return 0;
+
+err:
+	while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
+		dev_kfree_skb(skb);
+	return rc;
+}
+
+static int ntb_netdev_close(struct net_device *ndev)
+{
+	struct ntb_netdev *dev = netdev_priv(ndev);
+	struct sk_buff *skb;
+	int len;
+
+	ntb_transport_link_down(dev->qp);
+
+	while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
+		dev_kfree_skb(skb);
+
+	return 0;
+}
+
+static int ntb_netdev_change_mtu(struct net_device *ndev, int new_mtu)
+{
+	struct ntb_netdev *dev = netdev_priv(ndev);
+	struct sk_buff *skb;
+	int len, rc;
+
+	if (new_mtu > ntb_transport_max_size(dev->qp) - ETH_HLEN)
+		return -EINVAL;
+
+	if (!netif_running(ndev)) {
+		ndev->mtu = new_mtu;
+		return 0;
+	}
+
+	/* Bring down the link and dispose of posted rx entries */
+	ntb_transport_link_down(dev->qp);
+
+	if (ndev->mtu < new_mtu) {
+		int i;
+
+		for (i = 0; (skb = ntb_transport_rx_remove(dev->qp, &len)); i++)
+			dev_kfree_skb(skb);
+
+		for (; i; i--) {
+			skb = netdev_alloc_skb(ndev, new_mtu + ETH_HLEN);
+			if (!skb) {
+				rc = -ENOMEM;
+				goto err;
+			}
+
+			rc = ntb_transport_rx_enqueue(dev->qp, skb, skb->data,
+						      new_mtu + ETH_HLEN);
+			if (rc) {
+				dev_kfree_skb(skb);
+				goto err;
+			}
+		}
+	}
+
+	ndev->mtu = new_mtu;
+
+	ntb_transport_link_up(dev->qp);
+
+	return 0;
+
+err:
+	ntb_transport_link_down(dev->qp);
+
+	while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
+		dev_kfree_skb(skb);
+
+	netdev_err(ndev, "Error changing MTU, device inoperable\n");
+	return rc;
+}
+
+static void ntb_netdev_tx_timeout(struct net_device *ndev)
+{
+	if (netif_running(ndev))
+		netif_wake_queue(ndev);
+}
+
+static const struct net_device_ops ntb_netdev_ops = {
+	.ndo_open = ntb_netdev_open,
+	.ndo_stop = ntb_netdev_close,
+	.ndo_start_xmit = ntb_netdev_start_xmit,
+	.ndo_change_mtu = ntb_netdev_change_mtu,
+	.ndo_tx_timeout = ntb_netdev_tx_timeout,
+	.ndo_set_mac_address = eth_mac_addr,
+};
+
+static void ntb_get_drvinfo(struct net_device *ndev,
+			    struct ethtool_drvinfo *info)
+{
+	struct ntb_netdev *dev = netdev_priv(ndev);
+
+	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
+	strlcpy(info->version, NTB_NETDEV_VER, sizeof(info->version));
+	strlcpy(info->bus_info, pci_name(dev->pdev), sizeof(info->bus_info));
+}
+
+static int ntb_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+	cmd->supported = SUPPORTED_Backplane;
+	cmd->advertising = ADVERTISED_Backplane;
+	cmd->speed = SPEED_UNKNOWN;
+	ethtool_cmd_speed_set(cmd, SPEED_UNKNOWN);
+	cmd->duplex = DUPLEX_FULL;
+	cmd->port = PORT_OTHER;
+	cmd->phy_address = 0;
+	cmd->transceiver = XCVR_DUMMY1;
+	cmd->autoneg = AUTONEG_ENABLE;
+	cmd->maxtxpkt = 0;
+	cmd->maxrxpkt = 0;
+
+	return 0;
+}
+
+static const struct ethtool_ops ntb_ethtool_ops = {
+	.get_drvinfo = ntb_get_drvinfo,
+	.get_link = ethtool_op_get_link,
+	.get_settings = ntb_get_settings,
+};
+
+static const struct ntb_queue_handlers ntb_netdev_handlers = {
+	.tx_handler = ntb_netdev_tx_handler,
+	.rx_handler = ntb_netdev_rx_handler,
+	.event_handler = ntb_netdev_event_handler,
+};
+
+static int __devinit ntb_netdev_probe(struct pci_dev *pdev)
+{
+	struct net_device *ndev;
+	struct ntb_netdev *dev;
+	int rc;
+
+	ndev = alloc_etherdev(sizeof(struct ntb_netdev));
+	if (!ndev)
+		return -ENOMEM;
+
+	dev = netdev_priv(ndev);
+	dev->ndev = ndev;
+	dev->pdev = pdev;
+	BUG_ON(!dev->pdev);
+	ndev->features = NETIF_F_HIGHDMA;
+
+	//ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
+
+	ndev->hw_features = ndev->features;
+	ndev->watchdog_timeo = msecs_to_jiffies(NTB_TX_TIMEOUT_MS);
+
+	random_ether_addr(ndev->perm_addr);
+	memcpy(ndev->dev_addr, ndev->perm_addr, ndev->addr_len);
+
+	ndev->netdev_ops = &ntb_netdev_ops;
+	SET_ETHTOOL_OPS(ndev, &ntb_ethtool_ops);
+
+	dev->qp = ntb_transport_create_queue(ndev, pdev, &ntb_netdev_handlers);
+	if (!dev->qp) {
+		rc = -EIO;
+		goto err;
+	}
+
+	ndev->mtu = ntb_transport_max_size(dev->qp) - ETH_HLEN;
+
+	rc = register_netdev(ndev);
+	if (rc)
+		goto err1;
+
+	list_add(&dev->list, &dev_list);
+	pr_info("%s: %s created\n", KBUILD_MODNAME, ndev->name);
+	return 0;
+
+err1:
+	ntb_transport_free_queue(dev->qp);
+err:
+	free_netdev(ndev);
+	return rc;
+}
+
+static void __exit ntb_netdev_remove(struct pci_dev *pdev)
+{
+	struct net_device *ndev;
+	struct ntb_netdev *dev;
+
+	list_for_each_entry(dev, &dev_list, list) {
+		if (dev->pdev == pdev)
+			break;
+	}
+	if (dev == NULL)
+		return;
+
+	ndev = dev->ndev;
+
+	unregister_netdev(ndev);
+	ntb_transport_free_queue(dev->qp);
+	free_netdev(ndev);
+}
+
+static struct ntb_client ntb_netdev_client = {
+	.name = KBUILD_MODNAME,
+	.probe = ntb_netdev_probe,
+	.remove = ntb_netdev_remove,
+};
+
+static int __init ntb_netdev_init_module(void)
+{
+	return register_ntb_client(&ntb_netdev_client);
+}
+
+module_init(ntb_netdev_init_module);
+
+static void __exit ntb_netdev_exit_module(void)
+{
+	unregister_ntb_client(&ntb_netdev_client);
+	pr_info("%s: Driver removed\n", KBUILD_MODNAME);
+}
+
+module_exit(ntb_netdev_exit_module);