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

[Jon Mason <jon.mason@intel.com>]

A virtual ethernet device that uses the NTB transport API to send/receive data.

Signed-off-by: Jon Mason <jon.mason@intel.com>
---
 drivers/net/Kconfig      |    4 +
 drivers/net/Makefile     |    1 +
 drivers/net/ntb_netdev.c |  411 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 416 insertions(+), 0 deletions(-)
 create mode 100644 drivers/net/ntb_netdev.c

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..bcbd9d4
--- /dev/null
+++ b/drivers/net/ntb_netdev.c
@@ -0,0 +1,411 @@
+/*
+ * 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/ntb.h>
+
+#define NTB_NETDEV_VER	"0.4"
+
+MODULE_DESCRIPTION(KBUILD_MODNAME);
+MODULE_VERSION(NTB_NETDEV_VER);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Intel Corporation");
+
+struct ntb_netdev {
+	struct net_device *ndev;
+	struct ntb_transport_qp *qp;
+};
+
+#define	NTB_TX_TIMEOUT_MS	1000
+#define	NTB_RXQ_SIZE		100
+
+static struct net_device *netdev;
+
+static void ntb_netdev_event_handler(int status)
+{
+	struct ntb_netdev *dev = netdev_priv(netdev);
+
+	pr_debug("%s: Event %x, Link %x\n", KBUILD_MODNAME, status,
+		 ntb_transport_link_query(dev->qp));
+
+	/* Currently, only link status event is supported */
+	if (status)
+		netif_carrier_on(netdev);
+	else
+		netif_carrier_off(netdev);
+}
+
+static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp)
+{
+	struct net_device *ndev = netdev;
+	struct sk_buff *skb;
+	int len, rc;
+
+	while ((skb = ntb_transport_rx_dequeue(qp, &len))) {
+		pr_debug("%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++;
+			pr_err("%s: No skb\n", __func__);
+			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++;
+			pr_err("%s: error re-enqueuing\n", __func__);
+			break;
+		}
+	}
+}
+
+static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp)
+{
+	struct net_device *ndev = netdev;
+	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 (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;
+
+	pr_debug("%s: ntb_transport_tx_enqueue\n", KBUILD_MODNAME);
+
+	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)))
+		kfree(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)))
+		kfree(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++)
+			kfree(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) {
+				kfree(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)))
+		kfree(skb);
+
+	pr_err("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(__attribute__((unused)) struct net_device *dev,
+			    struct ethtool_drvinfo *info)
+{
+	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
+	strlcpy(info->version, NTB_NETDEV_VER, sizeof(info->version));
+}
+
+static const char ntb_nic_stats[][ETH_GSTRING_LEN] = {
+	"rx_packets", "rx_bytes", "rx_errors", "rx_dropped", "rx_length_errors",
+	"rx_frame_errors", "rx_fifo_errors",
+	"tx_packets", "tx_bytes", "tx_errors", "tx_dropped",
+};
+
+static int ntb_get_stats_count(__attribute__((unused)) struct net_device *dev)
+{
+	return ARRAY_SIZE(ntb_nic_stats);
+}
+
+static int ntb_get_sset_count(struct net_device *dev, int sset)
+{
+	switch (sset) {
+	case ETH_SS_STATS:
+		return ntb_get_stats_count(dev);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static void ntb_get_strings(__attribute__((unused)) struct net_device *dev,
+			    u32 sset, u8 *data)
+{
+	switch (sset) {
+	case ETH_SS_STATS:
+		memcpy(data, *ntb_nic_stats, sizeof(ntb_nic_stats));
+	}
+}
+
+static void
+ntb_get_ethtool_stats(struct net_device *dev,
+		      __attribute__((unused)) struct ethtool_stats *stats,
+		      u64 *data)
+{
+	int i = 0;
+
+	data[i++] = dev->stats.rx_packets;
+	data[i++] = dev->stats.rx_bytes;
+	data[i++] = dev->stats.rx_errors;
+	data[i++] = dev->stats.rx_dropped;
+	data[i++] = dev->stats.rx_length_errors;
+	data[i++] = dev->stats.rx_frame_errors;
+	data[i++] = dev->stats.rx_fifo_errors;
+	data[i++] = dev->stats.tx_packets;
+	data[i++] = dev->stats.tx_bytes;
+	data[i++] = dev->stats.tx_errors;
+	data[i++] = dev->stats.tx_dropped;
+}
+
+static const struct ethtool_ops ntb_ethtool_ops = {
+	.get_drvinfo = ntb_get_drvinfo,
+	.get_sset_count = ntb_get_sset_count,
+	.get_strings = ntb_get_strings,
+	.get_ethtool_stats = ntb_get_ethtool_stats,
+	.get_link = ethtool_op_get_link,
+};
+
+static int __init ntb_netdev_init_module(void)
+{
+	struct ntb_netdev *dev;
+	int rc;
+
+	pr_info("%s: Probe\n", KBUILD_MODNAME);
+
+	netdev = alloc_etherdev(sizeof(struct ntb_netdev));
+	if (!netdev)
+		return -ENOMEM;
+
+	dev = netdev_priv(netdev);
+	dev->ndev = netdev;
+	netdev->features = NETIF_F_HIGHDMA;
+
+	netdev->hw_features = netdev->features;
+	netdev->watchdog_timeo = msecs_to_jiffies(NTB_TX_TIMEOUT_MS);
+
+	random_ether_addr(netdev->perm_addr);
+	memcpy(netdev->dev_addr, netdev->perm_addr, netdev->addr_len);
+
+	netdev->netdev_ops = &ntb_netdev_ops;
+	SET_ETHTOOL_OPS(netdev, &ntb_ethtool_ops);
+
+	dev->qp = ntb_transport_create_queue(ntb_netdev_rx_handler,
+					     ntb_netdev_tx_handler,
+					     ntb_netdev_event_handler);
+	if (!dev->qp) {
+		rc = -EIO;
+		goto err;
+	}
+
+	netdev->mtu = ntb_transport_max_size(dev->qp) - ETH_HLEN;
+
+	rc = register_netdev(netdev);
+	if (rc)
+		goto err1;
+
+	pr_info("%s: %s created\n", KBUILD_MODNAME, netdev->name);
+	return 0;
+
+err1:
+	ntb_transport_free_queue(dev->qp);
+err:
+	free_netdev(netdev);
+	return rc;
+}
+module_init(ntb_netdev_init_module);
+
+static void __exit ntb_netdev_exit_module(void)
+{
+	struct ntb_netdev *dev = netdev_priv(netdev);
+
+	unregister_netdev(netdev);
+	ntb_transport_free_queue(dev->qp);
+	free_netdev(netdev);
+
+	pr_info("%s: Driver removed\n", KBUILD_MODNAME);
+}
+module_exit(ntb_netdev_exit_module);
-- 
1.7.5.4