Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking updates from David Miller:

 1) Seccomp BPF filters can now be JIT'd, from Alexei Starovoitov.

 2) Multiqueue support in xen-netback and xen-netfront, from Andrew J
    Benniston.

 3) Allow tweaking of aggregation settings in cdc_ncm driver, from Bjørn
    Mork.

 4) BPF now has a "random" opcode, from Chema Gonzalez.

 5) Add more BPF documentation and improve test framework, from Daniel
    Borkmann.

 6) Support TCP fastopen over ipv6, from Daniel Lee.

 7) Add software TSO helper functions and use them to support software
    TSO in mvneta and mv643xx_eth drivers.  From Ezequiel Garcia.

 8) Support software TSO in fec driver too, from Nimrod Andy.

 9) Add Broadcom SYSTEMPORT driver, from Florian Fainelli.

10) Handle broadcasts more gracefully over macvlan when there are large
    numbers of interfaces configured, from Herbert Xu.

11) Allow more control over fwmark used for non-socket based responses,
    from Lorenzo Colitti.

12) Do TCP congestion window limiting based upon measurements, from Neal
    Cardwell.

13) Support busy polling in SCTP, from Neal Horman.

14) Allow RSS key to be configured via ethtool, from Venkata Duvvuru.

15) Bridge promisc mode handling improvements from Vlad Yasevich.

16) Don't use inetpeer entries to implement ID generation any more, it
    performs poorly, from Eric Dumazet.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1522 commits)
  rtnetlink: fix userspace API breakage for iproute2 < v3.9.0
  tcp: fixing TLP's FIN recovery
  net: fec: Add software TSO support
  net: fec: Add Scatter/gather support
  net: fec: Increase buffer descriptor entry number
  net: fec: Factorize feature setting
  net: fec: Enable IP header hardware checksum
  net: fec: Factorize the .xmit transmit function
  bridge: fix compile error when compiling without IPv6 support
  bridge: fix smatch warning / potential null pointer dereference
  via-rhine: fix full-duplex with autoneg disable
  bnx2x: Enlarge the dorq threshold for VFs
  bnx2x: Check for UNDI in uncommon branch
  bnx2x: Fix 1G-baseT link
  bnx2x: Fix link for KR with swapped polarity lane
  sctp: Fix sk_ack_backlog wrap-around problem
  net/core: Add VF link state control policy
  net/fsl: xgmac_mdio is dependent on OF_MDIO
  net/fsl: Make xgmac_mdio read error message useful
  net_sched: drr: warn when qdisc is not work conserving
  ...

1 files changed, 971 insertions, 0 deletions

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
new file mode 100644
index 000000000000..04b0f84612f0
--- /dev/null
+++ b/drivers/net/can/usb/gs_usb.c
@@ -0,0 +1,971 @@
+/* CAN driver for Geschwister Schneider USB/CAN devices.
+ *
+ * Copyright (C) 2013 Geschwister Schneider Technologie-,
+ * Entwicklungs- und Vertriebs UG (Haftungsbeschränkt).
+ *
+ * Many thanks to all socketcan devs!
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; version 2 of the License.
+ *
+ * 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.
+ */
+
+#include <linux/init.h>
+#include <linux/signal.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/usb.h>
+
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+
+/* Device specific constants */
+#define USB_GSUSB_1_VENDOR_ID      0x1d50
+#define USB_GSUSB_1_PRODUCT_ID     0x606f
+
+#define GSUSB_ENDPOINT_IN          1
+#define GSUSB_ENDPOINT_OUT         2
+
+/* Device specific constants */
+enum gs_usb_breq {
+	GS_USB_BREQ_HOST_FORMAT = 0,
+	GS_USB_BREQ_BITTIMING,
+	GS_USB_BREQ_MODE,
+	GS_USB_BREQ_BERR,
+	GS_USB_BREQ_BT_CONST,
+	GS_USB_BREQ_DEVICE_CONFIG
+};
+
+enum gs_can_mode {
+	/* reset a channel. turns it off */
+	GS_CAN_MODE_RESET = 0,
+	/* starts a channel */
+	GS_CAN_MODE_START
+};
+
+enum gs_can_state {
+	GS_CAN_STATE_ERROR_ACTIVE = 0,
+	GS_CAN_STATE_ERROR_WARNING,
+	GS_CAN_STATE_ERROR_PASSIVE,
+	GS_CAN_STATE_BUS_OFF,
+	GS_CAN_STATE_STOPPED,
+	GS_CAN_STATE_SLEEPING
+};
+
+/* data types passed between host and device */
+struct gs_host_config {
+	u32 byte_order;
+} __packed;
+/* All data exchanged between host and device is exchanged in host byte order,
+ * thanks to the struct gs_host_config byte_order member, which is sent first
+ * to indicate the desired byte order.
+ */
+
+struct gs_device_config {
+	u8 reserved1;
+	u8 reserved2;
+	u8 reserved3;
+	u8 icount;
+	u32 sw_version;
+	u32 hw_version;
+} __packed;
+
+#define GS_CAN_MODE_NORMAL               0
+#define GS_CAN_MODE_LISTEN_ONLY          (1<<0)
+#define GS_CAN_MODE_LOOP_BACK            (1<<1)
+#define GS_CAN_MODE_TRIPLE_SAMPLE        (1<<2)
+#define GS_CAN_MODE_ONE_SHOT             (1<<3)
+
+struct gs_device_mode {
+	u32 mode;
+	u32 flags;
+} __packed;
+
+struct gs_device_state {
+	u32 state;
+	u32 rxerr;
+	u32 txerr;
+} __packed;
+
+struct gs_device_bittiming {
+	u32 prop_seg;
+	u32 phase_seg1;
+	u32 phase_seg2;
+	u32 sjw;
+	u32 brp;
+} __packed;
+
+#define GS_CAN_FEATURE_LISTEN_ONLY      (1<<0)
+#define GS_CAN_FEATURE_LOOP_BACK        (1<<1)
+#define GS_CAN_FEATURE_TRIPLE_SAMPLE    (1<<2)
+#define GS_CAN_FEATURE_ONE_SHOT         (1<<3)
+
+struct gs_device_bt_const {
+	u32 feature;
+	u32 fclk_can;
+	u32 tseg1_min;
+	u32 tseg1_max;
+	u32 tseg2_min;
+	u32 tseg2_max;
+	u32 sjw_max;
+	u32 brp_min;
+	u32 brp_max;
+	u32 brp_inc;
+} __packed;
+
+#define GS_CAN_FLAG_OVERFLOW 1
+
+struct gs_host_frame {
+	u32 echo_id;
+	u32 can_id;
+
+	u8 can_dlc;
+	u8 channel;
+	u8 flags;
+	u8 reserved;
+
+	u8 data[8];
+} __packed;
+/* The GS USB devices make use of the same flags and masks as in
+ * linux/can.h and linux/can/error.h, and no additional mapping is necessary.
+ */
+
+/* Only send a max of GS_MAX_TX_URBS frames per channel at a time. */
+#define GS_MAX_TX_URBS 10
+/* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
+#define GS_MAX_RX_URBS 30
+/* Maximum number of interfaces the driver supports per device.
+ * Current hardware only supports 2 interfaces. The future may vary.
+ */
+#define GS_MAX_INTF 2
+
+struct gs_tx_context {
+	struct gs_can *dev;
+	unsigned int echo_id;
+};
+
+struct gs_can {
+	struct can_priv can; /* must be the first member */
+
+	struct gs_usb *parent;
+
+	struct net_device *netdev;
+	struct usb_device *udev;
+	struct usb_interface *iface;
+
+	struct can_bittiming_const bt_const;
+	unsigned int channel;	/* channel number */
+
+	/* This lock prevents a race condition between xmit and recieve. */
+	spinlock_t tx_ctx_lock;
+	struct gs_tx_context tx_context[GS_MAX_TX_URBS];
+
+	struct usb_anchor tx_submitted;
+	atomic_t active_tx_urbs;
+};
+
+/* usb interface struct */
+struct gs_usb {
+	struct gs_can *canch[GS_MAX_INTF];
+	struct usb_anchor rx_submitted;
+	atomic_t active_channels;
+	struct usb_device *udev;
+};
+
+/* 'allocate' a tx context.
+ * returns a valid tx context or NULL if there is no space.
+ */
+static struct gs_tx_context *gs_alloc_tx_context(struct gs_can *dev)
+{
+	int i = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->tx_ctx_lock, flags);
+
+	for (; i < GS_MAX_TX_URBS; i++) {
+		if (dev->tx_context[i].echo_id == GS_MAX_TX_URBS) {
+			dev->tx_context[i].echo_id = i;
+			spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
+			return &dev->tx_context[i];
+		}
+	}
+
+	spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
+	return NULL;
+}
+
+/* releases a tx context
+ */
+static void gs_free_tx_context(struct gs_tx_context *txc)
+{
+	txc->echo_id = GS_MAX_TX_URBS;
+}
+
+/* Get a tx context by id.
+ */
+static struct gs_tx_context *gs_get_tx_context(struct gs_can *dev, unsigned int id)
+{
+	unsigned long flags;
+
+	if (id < GS_MAX_TX_URBS) {
+		spin_lock_irqsave(&dev->tx_ctx_lock, flags);
+		if (dev->tx_context[id].echo_id == id) {
+			spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
+			return &dev->tx_context[id];
+		}
+		spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
+	}
+	return NULL;
+}
+
+static int gs_cmd_reset(struct gs_usb *gsusb, struct gs_can *gsdev)
+{
+	struct gs_device_mode *dm;
+	struct usb_interface *intf = gsdev->iface;
+	int rc;
+
+	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
+	if (!dm)
+		return -ENOMEM;
+
+	dm->mode = GS_CAN_MODE_RESET;
+
+	rc = usb_control_msg(interface_to_usbdev(intf),
+			     usb_sndctrlpipe(interface_to_usbdev(intf), 0),
+			     GS_USB_BREQ_MODE,
+			     USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+			     gsdev->channel,
+			     0,
+			     dm,
+			     sizeof(*dm),
+			     1000);
+
+	return rc;
+}
+
+static void gs_update_state(struct gs_can *dev, struct can_frame *cf)
+{
+	struct can_device_stats *can_stats = &dev->can.can_stats;
+
+	if (cf->can_id & CAN_ERR_RESTARTED) {
+		dev->can.state = CAN_STATE_ERROR_ACTIVE;
+		can_stats->restarts++;
+	} else if (cf->can_id & CAN_ERR_BUSOFF) {
+		dev->can.state = CAN_STATE_BUS_OFF;
+		can_stats->bus_off++;
+	} else if (cf->can_id & CAN_ERR_CRTL) {
+		if ((cf->data[1] & CAN_ERR_CRTL_TX_WARNING) ||
+		    (cf->data[1] & CAN_ERR_CRTL_RX_WARNING)) {
+			dev->can.state = CAN_STATE_ERROR_WARNING;
+			can_stats->error_warning++;
+		} else if ((cf->data[1] & CAN_ERR_CRTL_TX_PASSIVE) ||
+			   (cf->data[1] & CAN_ERR_CRTL_RX_PASSIVE)) {
+			dev->can.state = CAN_STATE_ERROR_PASSIVE;
+			can_stats->error_passive++;
+		} else {
+			dev->can.state = CAN_STATE_ERROR_ACTIVE;
+		}
+	}
+}
+
+static void gs_usb_recieve_bulk_callback(struct urb *urb)
+{
+	struct gs_usb *usbcan = urb->context;
+	struct gs_can *dev;
+	struct net_device *netdev;
+	int rc;
+	struct net_device_stats *stats;
+	struct gs_host_frame *hf = urb->transfer_buffer;
+	struct gs_tx_context *txc;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	BUG_ON(!usbcan);
+
+	switch (urb->status) {
+	case 0: /* success */
+		break;
+	case -ENOENT:
+	case -ESHUTDOWN:
+		return;
+	default:
+		/* do not resubmit aborted urbs. eg: when device goes down */
+		return;
+	}
+
+	/* device reports out of range channel id */
+	if (hf->channel >= GS_MAX_INTF)
+		goto resubmit_urb;
+
+	dev = usbcan->canch[hf->channel];
+
+	netdev = dev->netdev;
+	stats = &netdev->stats;
+
+	if (!netif_device_present(netdev))
+		return;
+
+	if (hf->echo_id == -1) { /* normal rx */
+		skb = alloc_can_skb(dev->netdev, &cf);
+		if (!skb)
+			return;
+
+		cf->can_id = hf->can_id;
+
+		cf->can_dlc = get_can_dlc(hf->can_dlc);
+		memcpy(cf->data, hf->data, 8);
+
+		/* ERROR frames tell us information about the controller */
+		if (hf->can_id & CAN_ERR_FLAG)
+			gs_update_state(dev, cf);
+
+		netdev->stats.rx_packets++;
+		netdev->stats.rx_bytes += hf->can_dlc;
+
+		netif_rx(skb);
+	} else { /* echo_id == hf->echo_id */
+		if (hf->echo_id >= GS_MAX_TX_URBS) {
+			netdev_err(netdev,
+				   "Unexpected out of range echo id %d\n",
+				   hf->echo_id);
+			goto resubmit_urb;
+		}
+
+		netdev->stats.tx_packets++;
+		netdev->stats.tx_bytes += hf->can_dlc;
+
+		txc = gs_get_tx_context(dev, hf->echo_id);
+
+		/* bad devices send bad echo_ids. */
+		if (!txc) {
+			netdev_err(netdev,
+				   "Unexpected unused echo id %d\n",
+				   hf->echo_id);
+			goto resubmit_urb;
+		}
+
+		can_get_echo_skb(netdev, hf->echo_id);
+
+		gs_free_tx_context(txc);
+
+		netif_wake_queue(netdev);
+	}
+
+	if (hf->flags & GS_CAN_FLAG_OVERFLOW) {
+		skb = alloc_can_err_skb(netdev, &cf);
+		if (!skb)
+			goto resubmit_urb;
+
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->can_dlc = CAN_ERR_DLC;
+		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		stats->rx_over_errors++;
+		stats->rx_errors++;
+		netif_rx(skb);
+	}
+
+ resubmit_urb:
+	usb_fill_bulk_urb(urb,
+			  usbcan->udev,
+			  usb_rcvbulkpipe(usbcan->udev, GSUSB_ENDPOINT_IN),
+			  hf,
+			  sizeof(struct gs_host_frame),
+			  gs_usb_recieve_bulk_callback,
+			  usbcan
+			  );
+
+	rc = usb_submit_urb(urb, GFP_ATOMIC);
+
+	/* USB failure take down all interfaces */
+	if (rc == -ENODEV) {
+		for (rc = 0; rc < GS_MAX_INTF; rc++) {
+			if (usbcan->canch[rc])
+				netif_device_detach(usbcan->canch[rc]->netdev);
+		}
+	}
+}
+
+static int gs_usb_set_bittiming(struct net_device *netdev)
+{
+	struct gs_can *dev = netdev_priv(netdev);
+	struct can_bittiming *bt = &dev->can.bittiming;
+	struct usb_interface *intf = dev->iface;
+	int rc;
+	struct gs_device_bittiming *dbt;
+
+	dbt = kmalloc(sizeof(*dbt), GFP_KERNEL);
+	if (!dbt)
+		return -ENOMEM;
+
+	dbt->prop_seg = bt->prop_seg;
+	dbt->phase_seg1 = bt->phase_seg1;
+	dbt->phase_seg2 = bt->phase_seg2;
+	dbt->sjw = bt->sjw;
+	dbt->brp = bt->brp;
+
+	/* request bit timings */
+	rc = usb_control_msg(interface_to_usbdev(intf),
+			     usb_sndctrlpipe(interface_to_usbdev(intf), 0),
+			     GS_USB_BREQ_BITTIMING,
+			     USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+			     dev->channel,
+			     0,
+			     dbt,
+			     sizeof(*dbt),
+			     1000);
+
+	kfree(dbt);
+
+	if (rc < 0)
+		dev_err(netdev->dev.parent, "Couldn't set bittimings (err=%d)",
+			rc);
+
+	return rc;
+}
+
+static void gs_usb_xmit_callback(struct urb *urb)
+{
+	struct gs_tx_context *txc = urb->context;
+	struct gs_can *dev = txc->dev;
+	struct net_device *netdev = dev->netdev;
+
+	if (urb->status)
+		netdev_info(netdev, "usb xmit fail %d\n", txc->echo_id);
+
+	usb_free_coherent(urb->dev,
+			  urb->transfer_buffer_length,
+			  urb->transfer_buffer,
+			  urb->transfer_dma);
+
+	atomic_dec(&dev->active_tx_urbs);
+
+	if (!netif_device_present(netdev))
+		return;
+
+	if (netif_queue_stopped(netdev))
+		netif_wake_queue(netdev);
+}
+
+static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+	struct gs_can *dev = netdev_priv(netdev);
+	struct net_device_stats *stats = &dev->netdev->stats;
+	struct urb *urb;
+	struct gs_host_frame *hf;
+	struct can_frame *cf;
+	int rc;
+	unsigned int idx;
+	struct gs_tx_context *txc;
+
+	if (can_dropped_invalid_skb(netdev, skb))
+		return NETDEV_TX_OK;
+
+	/* find an empty context to keep track of transmission */
+	txc = gs_alloc_tx_context(dev);
+	if (!txc)
+		return NETDEV_TX_BUSY;
+
+	/* create a URB, and a buffer for it */
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb) {
+		netdev_err(netdev, "No memory left for URB\n");
+		goto nomem_urb;
+	}
+
+	hf = usb_alloc_coherent(dev->udev, sizeof(*hf), GFP_ATOMIC,
+				&urb->transfer_dma);
+	if (!hf) {
+		netdev_err(netdev, "No memory left for USB buffer\n");
+		goto nomem_hf;
+	}
+
+	idx = txc->echo_id;
+
+	if (idx >= GS_MAX_TX_URBS) {
+		netdev_err(netdev, "Invalid tx context %d\n", idx);
+		goto badidx;
+	}
+
+	hf->echo_id = idx;
+	hf->channel = dev->channel;
+
+	cf = (struct can_frame *)skb->data;
+
+	hf->can_id = cf->can_id;
+	hf->can_dlc = cf->can_dlc;
+	memcpy(hf->data, cf->data, cf->can_dlc);
+
+	usb_fill_bulk_urb(urb, dev->udev,
+			  usb_sndbulkpipe(dev->udev, GSUSB_ENDPOINT_OUT),
+			  hf,
+			  sizeof(*hf),
+			  gs_usb_xmit_callback,
+			  txc);
+
+	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	usb_anchor_urb(urb, &dev->tx_submitted);
+
+	can_put_echo_skb(skb, netdev, idx);
+
+	atomic_inc(&dev->active_tx_urbs);
+
+	rc = usb_submit_urb(urb, GFP_ATOMIC);
+	if (unlikely(rc)) {			/* usb send failed */
+		atomic_dec(&dev->active_tx_urbs);
+
+		can_free_echo_skb(netdev, idx);
+		gs_free_tx_context(txc);
+
+		usb_unanchor_urb(urb);
+		usb_free_coherent(dev->udev,
+				  sizeof(*hf),
+				  hf,
+				  urb->transfer_dma);
+
+
+		if (rc == -ENODEV) {
+			netif_device_detach(netdev);
+		} else {
+			netdev_err(netdev, "usb_submit failed (err=%d)\n", rc);
+			stats->tx_dropped++;
+		}
+	} else {
+		/* Slow down tx path */
+		if (atomic_read(&dev->active_tx_urbs) >= GS_MAX_TX_URBS)
+			netif_stop_queue(netdev);
+	}
+
+	/* let usb core take care of this urb */
+	usb_free_urb(urb);
+
+	return NETDEV_TX_OK;
+
+ badidx:
+	usb_free_coherent(dev->udev,
+			  sizeof(*hf),
+			  hf,
+			  urb->transfer_dma);
+ nomem_hf:
+	usb_free_urb(urb);
+
+ nomem_urb:
+	gs_free_tx_context(txc);
+	dev_kfree_skb(skb);
+	stats->tx_dropped++;
+	return NETDEV_TX_OK;
+}
+
+static int gs_can_open(struct net_device *netdev)
+{
+	struct gs_can *dev = netdev_priv(netdev);
+	struct gs_usb *parent = dev->parent;
+	int rc, i;
+	struct gs_device_mode *dm;
+	u32 ctrlmode;
+
+	rc = open_candev(netdev);
+	if (rc)
+		return rc;
+
+	if (atomic_add_return(1, &parent->active_channels) == 1) {
+		for (i = 0; i < GS_MAX_RX_URBS; i++) {
+			struct urb *urb;
+			u8 *buf;
+
+			/* alloc rx urb */
+			urb = usb_alloc_urb(0, GFP_KERNEL);
+			if (!urb) {
+				netdev_err(netdev,
+					   "No memory left for URB\n");
+				return -ENOMEM;
+			}
+
+			/* alloc rx buffer */
+			buf = usb_alloc_coherent(dev->udev,
+						 sizeof(struct gs_host_frame),
+						 GFP_KERNEL,
+						 &urb->transfer_dma);
+			if (!buf) {
+				netdev_err(netdev,
+					   "No memory left for USB buffer\n");
+				usb_free_urb(urb);
+				return -ENOMEM;
+			}
+
+			/* fill, anchor, and submit rx urb */
+			usb_fill_bulk_urb(urb,
+					  dev->udev,
+					  usb_rcvbulkpipe(dev->udev,
+							  GSUSB_ENDPOINT_IN),
+					  buf,
+					  sizeof(struct gs_host_frame),
+					  gs_usb_recieve_bulk_callback,
+					  parent);
+			urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+			usb_anchor_urb(urb, &parent->rx_submitted);
+
+			rc = usb_submit_urb(urb, GFP_KERNEL);
+			if (rc) {
+				if (rc == -ENODEV)
+					netif_device_detach(dev->netdev);
+
+				netdev_err(netdev,
+					   "usb_submit failed (err=%d)\n",
+					   rc);
+
+				usb_unanchor_urb(urb);
+				break;
+			}
+
+			/* Drop reference,
+			 * USB core will take care of freeing it
+			 */
+			usb_free_urb(urb);
+		}
+	}
+
+	dm = kmalloc(sizeof(*dm), GFP_KERNEL);
+	if (!dm)
+		return -ENOMEM;
+
+	/* flags */
+	ctrlmode = dev->can.ctrlmode;
+	dm->flags = 0;
+
+	if (ctrlmode & CAN_CTRLMODE_LOOPBACK)
+		dm->flags |= GS_CAN_MODE_LOOP_BACK;
+	else if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		dm->flags |= GS_CAN_MODE_LISTEN_ONLY;
+
+	/* Controller is not allowed to retry TX
+	 * this mode is unavailable on atmels uc3c hardware
+	 */
+	if (ctrlmode & CAN_CTRLMODE_ONE_SHOT)
+		dm->flags |= GS_CAN_MODE_ONE_SHOT;
+
+	if (ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+		dm->flags |= GS_CAN_MODE_TRIPLE_SAMPLE;
+
+	/* finally start device */
+	dm->mode = GS_CAN_MODE_START;
+	rc = usb_control_msg(interface_to_usbdev(dev->iface),
+			     usb_sndctrlpipe(interface_to_usbdev(dev->iface), 0),
+			     GS_USB_BREQ_MODE,
+			     USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+			     dev->channel,
+			     0,
+			     dm,
+			     sizeof(*dm),
+			     1000);
+
+	if (rc < 0) {
+		netdev_err(netdev, "Couldn't start device (err=%d)\n", rc);
+		kfree(dm);
+		return rc;
+	}
+
+	kfree(dm);
+
+	dev->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
+		netif_start_queue(netdev);
+
+	return 0;
+}
+
+static int gs_can_close(struct net_device *netdev)
+{
+	int rc;
+	struct gs_can *dev = netdev_priv(netdev);
+	struct gs_usb *parent = dev->parent;
+
+	netif_stop_queue(netdev);
+
+	/* Stop polling */
+	if (atomic_dec_and_test(&parent->active_channels))
+		usb_kill_anchored_urbs(&parent->rx_submitted);
+
+	/* Stop sending URBs */
+	usb_kill_anchored_urbs(&dev->tx_submitted);
+	atomic_set(&dev->active_tx_urbs, 0);
+
+	/* reset the device */
+	rc = gs_cmd_reset(parent, dev);
+	if (rc < 0)
+		netdev_warn(netdev, "Couldn't shutdown device (err=%d)", rc);
+
+	/* reset tx contexts */
+	for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
+		dev->tx_context[rc].dev = dev;
+		dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
+	}
+
+	/* close the netdev */
+	close_candev(netdev);
+
+	return 0;
+}
+
+static const struct net_device_ops gs_usb_netdev_ops = {
+	.ndo_open = gs_can_open,
+	.ndo_stop = gs_can_close,
+	.ndo_start_xmit = gs_can_start_xmit,
+};
+
+static struct gs_can *gs_make_candev(unsigned int channel, struct usb_interface *intf)
+{
+	struct gs_can *dev;
+	struct net_device *netdev;
+	int rc;
+	struct gs_device_bt_const *bt_const;
+
+	bt_const = kmalloc(sizeof(*bt_const), GFP_KERNEL);
+	if (!bt_const)
+		return ERR_PTR(-ENOMEM);
+
+	/* fetch bit timing constants */
+	rc = usb_control_msg(interface_to_usbdev(intf),
+			     usb_rcvctrlpipe(interface_to_usbdev(intf), 0),
+			     GS_USB_BREQ_BT_CONST,
+			     USB_DIR_IN|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+			     channel,
+			     0,
+			     bt_const,
+			     sizeof(*bt_const),
+			     1000);
+
+	if (rc < 0) {
+		dev_err(&intf->dev,
+			"Couldn't get bit timing const for channel (err=%d)\n",
+			rc);
+		kfree(bt_const);
+		return ERR_PTR(rc);
+	}
+
+	/* create netdev */
+	netdev = alloc_candev(sizeof(struct gs_can), GS_MAX_TX_URBS);
+	if (!netdev) {
+		dev_err(&intf->dev, "Couldn't allocate candev\n");
+		kfree(bt_const);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	dev = netdev_priv(netdev);
+
+	netdev->netdev_ops = &gs_usb_netdev_ops;
+
+	netdev->flags |= IFF_ECHO; /* we support full roundtrip echo */
+
+	/* dev settup */
+	strcpy(dev->bt_const.name, "gs_usb");
+	dev->bt_const.tseg1_min = bt_const->tseg1_min;
+	dev->bt_const.tseg1_max = bt_const->tseg1_max;
+	dev->bt_const.tseg2_min = bt_const->tseg2_min;
+	dev->bt_const.tseg2_max = bt_const->tseg2_max;
+	dev->bt_const.sjw_max = bt_const->sjw_max;
+	dev->bt_const.brp_min = bt_const->brp_min;
+	dev->bt_const.brp_max = bt_const->brp_max;
+	dev->bt_const.brp_inc = bt_const->brp_inc;
+
+	dev->udev = interface_to_usbdev(intf);
+	dev->iface = intf;
+	dev->netdev = netdev;
+	dev->channel = channel;
+
+	init_usb_anchor(&dev->tx_submitted);
+	atomic_set(&dev->active_tx_urbs, 0);
+	spin_lock_init(&dev->tx_ctx_lock);
+	for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
+		dev->tx_context[rc].dev = dev;
+		dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
+	}
+
+	/* can settup */
+	dev->can.state = CAN_STATE_STOPPED;
+	dev->can.clock.freq = bt_const->fclk_can;
+	dev->can.bittiming_const = &dev->bt_const;
+	dev->can.do_set_bittiming = gs_usb_set_bittiming;
+
+	dev->can.ctrlmode_supported = 0;
+
+	if (bt_const->feature & GS_CAN_FEATURE_LISTEN_ONLY)
+		dev->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
+
+	if (bt_const->feature & GS_CAN_FEATURE_LOOP_BACK)
+		dev->can.ctrlmode_supported |= CAN_CTRLMODE_LOOPBACK;
+
+	if (bt_const->feature & GS_CAN_FEATURE_TRIPLE_SAMPLE)
+		dev->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
+
+	if (bt_const->feature & GS_CAN_FEATURE_ONE_SHOT)
+		dev->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;
+
+	kfree(bt_const);
+
+	SET_NETDEV_DEV(netdev, &intf->dev);
+
+	rc = register_candev(dev->netdev);
+	if (rc) {
+		free_candev(dev->netdev);
+		dev_err(&intf->dev, "Couldn't register candev (err=%d)\n", rc);
+		return ERR_PTR(rc);
+	}
+
+	return dev;
+}
+
+static void gs_destroy_candev(struct gs_can *dev)
+{
+	unregister_candev(dev->netdev);
+	free_candev(dev->netdev);
+	usb_kill_anchored_urbs(&dev->tx_submitted);
+	kfree(dev);
+}
+
+static int gs_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	struct gs_usb *dev;
+	int rc = -ENOMEM;
+	unsigned int icount, i;
+	struct gs_host_config *hconf;
+	struct gs_device_config *dconf;
+
+	hconf = kmalloc(sizeof(*hconf), GFP_KERNEL);
+	if (!hconf)
+		return -ENOMEM;
+
+	hconf->byte_order = 0x0000beef;
+
+	/* send host config */
+	rc = usb_control_msg(interface_to_usbdev(intf),
+			     usb_sndctrlpipe(interface_to_usbdev(intf), 0),
+			     GS_USB_BREQ_HOST_FORMAT,
+			     USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+			     1,
+			     intf->altsetting[0].desc.bInterfaceNumber,
+			     hconf,
+			     sizeof(*hconf),
+			     1000);
+
+	kfree(hconf);
+
+	if (rc < 0) {
+		dev_err(&intf->dev, "Couldn't send data format (err=%d)\n",
+			rc);
+		return rc;
+	}
+
+	dconf = kmalloc(sizeof(*dconf), GFP_KERNEL);
+	if (!dconf)
+		return -ENOMEM;
+
+	/* read device config */
+	rc = usb_control_msg(interface_to_usbdev(intf),
+			     usb_rcvctrlpipe(interface_to_usbdev(intf), 0),
+			     GS_USB_BREQ_DEVICE_CONFIG,
+			     USB_DIR_IN|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+			     1,
+			     intf->altsetting[0].desc.bInterfaceNumber,
+			     dconf,
+			     sizeof(*dconf),
+			     1000);
+	if (rc < 0) {
+		dev_err(&intf->dev, "Couldn't get device config: (err=%d)\n",
+			rc);
+
+		kfree(dconf);
+
+		return rc;
+	}
+
+	icount = dconf->icount+1;
+
+	kfree(dconf);
+
+	dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);
+
+	if (icount > GS_MAX_INTF) {
+		dev_err(&intf->dev,
+			"Driver cannot handle more that %d CAN interfaces\n",
+			GS_MAX_INTF);
+		return -EINVAL;
+	}
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	init_usb_anchor(&dev->rx_submitted);
+
+	atomic_set(&dev->active_channels, 0);
+
+	usb_set_intfdata(intf, dev);
+	dev->udev = interface_to_usbdev(intf);
+
+	for (i = 0; i < icount; i++) {
+		dev->canch[i] = gs_make_candev(i, intf);
+		if (IS_ERR_OR_NULL(dev->canch[i])) {
+			/* on failure destroy previously created candevs */
+			icount = i;
+			for (i = 0; i < icount; i++) {
+				gs_destroy_candev(dev->canch[i]);
+				dev->canch[i] = NULL;
+			}
+			kfree(dev);
+			return rc;
+		}
+		dev->canch[i]->parent = dev;
+	}
+
+	return 0;
+}
+
+static void gs_usb_disconnect(struct usb_interface *intf)
+{
+	unsigned i;
+	struct gs_usb *dev = usb_get_intfdata(intf);
+	usb_set_intfdata(intf, NULL);
+
+	if (!dev) {
+		dev_err(&intf->dev, "Disconnect (nodata)\n");
+		return;
+	}
+
+	for (i = 0; i < GS_MAX_INTF; i++) {
+		struct gs_can *can = dev->canch[i];
+
+		if (!can)
+			continue;
+
+		gs_destroy_candev(can);
+	}
+
+	usb_kill_anchored_urbs(&dev->rx_submitted);
+}
+
+static const struct usb_device_id gs_usb_table[] = {
+	{USB_DEVICE(USB_GSUSB_1_VENDOR_ID, USB_GSUSB_1_PRODUCT_ID)},
+	{} /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, gs_usb_table);
+
+static struct usb_driver gs_usb_driver = {
+	.name       = "gs_usb",
+	.probe      = gs_usb_probe,
+	.disconnect = gs_usb_disconnect,
+	.id_table   = gs_usb_table,
+};
+
+module_usb_driver(gs_usb_driver);
+
+MODULE_AUTHOR("Maximilian Schneider <mws@schneidersoft.net>");
+MODULE_DESCRIPTION(
+"Socket CAN device driver for Geschwister Schneider Technologie-, "
+"Entwicklungs- und Vertriebs UG. USB2.0 to CAN interfaces.");
+MODULE_LICENSE("GPL v2");