can: Add driver for esd CAN-USB/2 device
authorMatthias Fuchs <matthias.fuchs@esd.eu>
Tue, 3 Aug 2010 02:55:23 +0000 (02:55 +0000)
committerDavid S. Miller <davem@davemloft.net>
Tue, 3 Aug 2010 23:37:58 +0000 (16:37 -0700)
This patch adds a driver for esd's USB high speed
CAN interface. The driver supports devices with
multiple CAN interfaces.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/can/usb/Kconfig
drivers/net/can/usb/Makefile
drivers/net/can/usb/esd_usb2.c [new file with mode: 0644]

index 97ff6fe..0452549 100644 (file)
@@ -7,4 +7,10 @@ config CAN_EMS_USB
          This driver is for the one channel CPC-USB/ARM7 CAN/USB interface
          from EMS Dr. Thomas Wuensche (http://www.ems-wuensche.de).
 
+config CAN_ESD_USB2
+        tristate "ESD USB/2 CAN/USB interface"
+        ---help---
+          This driver supports the CAN-USB/2 interface
+          from esd electronic system design gmbh (http://www.esd.eu).
+
 endmenu
index 0afd51d..fce3cf1 100644 (file)
@@ -3,5 +3,6 @@
 #
 
 obj-$(CONFIG_CAN_EMS_USB) += ems_usb.o
+obj-$(CONFIG_CAN_ESD_USB2) += esd_usb2.o
 
 ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
diff --git a/drivers/net/can/usb/esd_usb2.c b/drivers/net/can/usb/esd_usb2.c
new file mode 100644 (file)
index 0000000..05a5275
--- /dev/null
@@ -0,0 +1,1132 @@
+/*
+ * CAN driver for esd CAN-USB/2
+ *
+ * Copyright (C) 2010 Matthias Fuchs <matthias.fuchs@esd.eu>, esd gmbh
+ *
+ * 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.
+ *
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include <linux/init.h>
+#include <linux/signal.h>
+#include <linux/slab.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>
+
+MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd.eu>");
+MODULE_DESCRIPTION("CAN driver for esd CAN-USB/2 interfaces");
+MODULE_LICENSE("GPL v2");
+
+/* Define these values to match your devices */
+#define USB_ESDGMBH_VENDOR_ID  0x0ab4
+#define USB_CANUSB2_PRODUCT_ID 0x0010
+
+#define ESD_USB2_CAN_CLOCK     60000000
+#define ESD_USB2_MAX_NETS      2
+
+/* USB2 commands */
+#define CMD_VERSION            1 /* also used for VERSION_REPLY */
+#define CMD_CAN_RX             2 /* device to host only */
+#define CMD_CAN_TX             3 /* also used for TX_DONE */
+#define CMD_SETBAUD            4 /* also used for SETBAUD_REPLY */
+#define CMD_TS                 5 /* also used for TS_REPLY */
+#define CMD_IDADD              6 /* also used for IDADD_REPLY */
+
+/* esd CAN message flags - dlc field */
+#define ESD_RTR                        0x10
+
+/* esd CAN message flags - id field */
+#define ESD_EXTID              0x20000000
+#define ESD_EVENT              0x40000000
+#define ESD_IDMASK             0x1fffffff
+
+/* esd CAN event ids used by this driver */
+#define ESD_EV_CAN_ERROR_EXT   2
+
+/* baudrate message flags */
+#define ESD_USB2_UBR           0x80000000
+#define ESD_USB2_LOM           0x40000000
+#define ESD_USB2_NO_BAUDRATE   0x7fffffff
+#define ESD_USB2_TSEG1_MIN     1
+#define ESD_USB2_TSEG1_MAX     16
+#define ESD_USB2_TSEG1_SHIFT   16
+#define ESD_USB2_TSEG2_MIN     1
+#define ESD_USB2_TSEG2_MAX     8
+#define ESD_USB2_TSEG2_SHIFT   20
+#define ESD_USB2_SJW_MAX       4
+#define ESD_USB2_SJW_SHIFT     14
+#define ESD_USB2_BRP_MIN       1
+#define ESD_USB2_BRP_MAX       1024
+#define ESD_USB2_BRP_INC       1
+#define ESD_USB2_3_SAMPLES     0x00800000
+
+/* esd IDADD message */
+#define ESD_ID_ENABLE          0x80
+#define ESD_MAX_ID_SEGMENT     64
+
+/* SJA1000 ECC register (emulated by usb2 firmware) */
+#define SJA1000_ECC_SEG                0x1F
+#define SJA1000_ECC_DIR                0x20
+#define SJA1000_ECC_ERR                0x06
+#define SJA1000_ECC_BIT                0x00
+#define SJA1000_ECC_FORM       0x40
+#define SJA1000_ECC_STUFF      0x80
+#define SJA1000_ECC_MASK       0xc0
+
+/* esd bus state event codes */
+#define ESD_BUSSTATE_MASK      0xc0
+#define ESD_BUSSTATE_WARN      0x40
+#define ESD_BUSSTATE_ERRPASSIVE        0x80
+#define ESD_BUSSTATE_BUSOFF    0xc0
+
+#define RX_BUFFER_SIZE         1024
+#define MAX_RX_URBS            4
+#define MAX_TX_URBS            16 /* must be power of 2 */
+
+struct header_msg {
+       u8 len; /* len is always the total message length in 32bit words */
+       u8 cmd;
+       u8 rsvd[2];
+};
+
+struct version_msg {
+       u8 len;
+       u8 cmd;
+       u8 rsvd;
+       u8 flags;
+       __le32 drv_version;
+};
+
+struct version_reply_msg {
+       u8 len;
+       u8 cmd;
+       u8 nets;
+       u8 features;
+       __le32 version;
+       u8 name[16];
+       __le32 rsvd;
+       __le32 ts;
+};
+
+struct rx_msg {
+       u8 len;
+       u8 cmd;
+       u8 net;
+       u8 dlc;
+       __le32 ts;
+       __le32 id; /* upper 3 bits contain flags */
+       u8 data[8];
+};
+
+struct tx_msg {
+       u8 len;
+       u8 cmd;
+       u8 net;
+       u8 dlc;
+       __le32 hnd;
+       __le32 id; /* upper 3 bits contain flags */
+       u8 data[8];
+};
+
+struct tx_done_msg {
+       u8 len;
+       u8 cmd;
+       u8 net;
+       u8 status;
+       __le32 hnd;
+       __le32 ts;
+};
+
+struct id_filter_msg {
+       u8 len;
+       u8 cmd;
+       u8 net;
+       u8 option;
+       __le32 mask[ESD_MAX_ID_SEGMENT + 1];
+};
+
+struct set_baudrate_msg {
+       u8 len;
+       u8 cmd;
+       u8 net;
+       u8 rsvd;
+       __le32 baud;
+};
+
+/* Main message type used between library and application */
+struct __attribute__ ((packed)) esd_usb2_msg {
+       union {
+               struct header_msg hdr;
+               struct version_msg version;
+               struct version_reply_msg version_reply;
+               struct rx_msg rx;
+               struct tx_msg tx;
+               struct tx_done_msg txdone;
+               struct set_baudrate_msg setbaud;
+               struct id_filter_msg filter;
+       } msg;
+};
+
+static struct usb_device_id esd_usb2_table[] = {
+       {USB_DEVICE(USB_ESDGMBH_VENDOR_ID, USB_CANUSB2_PRODUCT_ID)},
+       {}
+};
+MODULE_DEVICE_TABLE(usb, esd_usb2_table);
+
+struct esd_usb2_net_priv;
+
+struct esd_tx_urb_context {
+       struct esd_usb2_net_priv *priv;
+       u32 echo_index;
+       int dlc;
+};
+
+struct esd_usb2 {
+       struct usb_device *udev;
+       struct esd_usb2_net_priv *nets[ESD_USB2_MAX_NETS];
+
+       struct usb_anchor rx_submitted;
+
+       int net_count;
+       u32 version;
+       int rxinitdone;
+};
+
+struct esd_usb2_net_priv {
+       struct can_priv can; /* must be the first member */
+
+       atomic_t active_tx_jobs;
+       struct usb_anchor tx_submitted;
+       struct esd_tx_urb_context tx_contexts[MAX_TX_URBS];
+
+       int open_time;
+       struct esd_usb2 *usb2;
+       struct net_device *netdev;
+       int index;
+       u8 old_state;
+       struct can_berr_counter bec;
+};
+
+static void esd_usb2_rx_event(struct esd_usb2_net_priv *priv,
+                             struct esd_usb2_msg *msg)
+{
+       struct net_device_stats *stats = &priv->netdev->stats;
+       struct can_frame *cf;
+       struct sk_buff *skb;
+       u32 id = le32_to_cpu(msg->msg.rx.id) & ESD_IDMASK;
+
+       if (id == ESD_EV_CAN_ERROR_EXT) {
+               u8 state = msg->msg.rx.data[0];
+               u8 ecc = msg->msg.rx.data[1];
+               u8 txerr = msg->msg.rx.data[2];
+               u8 rxerr = msg->msg.rx.data[3];
+
+               skb = alloc_can_err_skb(priv->netdev, &cf);
+               if (skb == NULL) {
+                       stats->rx_dropped++;
+                       return;
+               }
+
+               if (state != priv->old_state) {
+                       priv->old_state = state;
+
+                       switch (state & ESD_BUSSTATE_MASK) {
+                       case ESD_BUSSTATE_BUSOFF:
+                               priv->can.state = CAN_STATE_BUS_OFF;
+                               cf->can_id |= CAN_ERR_BUSOFF;
+                               can_bus_off(priv->netdev);
+                               break;
+                       case ESD_BUSSTATE_WARN:
+                               priv->can.state = CAN_STATE_ERROR_WARNING;
+                               priv->can.can_stats.error_warning++;
+                               break;
+                       case ESD_BUSSTATE_ERRPASSIVE:
+                               priv->can.state = CAN_STATE_ERROR_PASSIVE;
+                               priv->can.can_stats.error_passive++;
+                               break;
+                       default:
+                               priv->can.state = CAN_STATE_ERROR_ACTIVE;
+                               break;
+                       }
+               } else {
+                       priv->can.can_stats.bus_error++;
+                       stats->rx_errors++;
+
+                       cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+                       switch (ecc & SJA1000_ECC_MASK) {
+                       case SJA1000_ECC_BIT:
+                               cf->data[2] |= CAN_ERR_PROT_BIT;
+                               break;
+                       case SJA1000_ECC_FORM:
+                               cf->data[2] |= CAN_ERR_PROT_FORM;
+                               break;
+                       case SJA1000_ECC_STUFF:
+                               cf->data[2] |= CAN_ERR_PROT_STUFF;
+                               break;
+                       default:
+                               cf->data[2] |= CAN_ERR_PROT_UNSPEC;
+                               cf->data[3] = ecc & SJA1000_ECC_SEG;
+                               break;
+                       }
+
+                       /* Error occured during transmission? */
+                       if (!(ecc & SJA1000_ECC_DIR))
+                               cf->data[2] |= CAN_ERR_PROT_TX;
+
+                       if (priv->can.state == CAN_STATE_ERROR_WARNING ||
+                           priv->can.state == CAN_STATE_ERROR_PASSIVE) {
+                               cf->data[1] = (txerr > rxerr) ?
+                                       CAN_ERR_CRTL_TX_PASSIVE :
+                                       CAN_ERR_CRTL_RX_PASSIVE;
+                       }
+                       cf->data[6] = txerr;
+                       cf->data[7] = rxerr;
+               }
+
+               netif_rx(skb);
+
+               priv->bec.txerr = txerr;
+               priv->bec.rxerr = rxerr;
+
+               stats->rx_packets++;
+               stats->rx_bytes += cf->can_dlc;
+       }
+}
+
+static void esd_usb2_rx_can_msg(struct esd_usb2_net_priv *priv,
+                               struct esd_usb2_msg *msg)
+{
+       struct net_device_stats *stats = &priv->netdev->stats;
+       struct can_frame *cf;
+       struct sk_buff *skb;
+       int i;
+       u32 id;
+
+       if (!netif_device_present(priv->netdev))
+               return;
+
+       id = le32_to_cpu(msg->msg.rx.id);
+
+       if (id & ESD_EVENT) {
+               esd_usb2_rx_event(priv, msg);
+       } else {
+               skb = alloc_can_skb(priv->netdev, &cf);
+               if (skb == NULL) {
+                       stats->rx_dropped++;
+                       return;
+               }
+
+               cf->can_id = id & ESD_IDMASK;
+               cf->can_dlc = get_can_dlc(msg->msg.rx.dlc);
+
+               if (id & ESD_EXTID)
+                       cf->can_id |= CAN_EFF_FLAG;
+
+               if (msg->msg.rx.dlc & ESD_RTR) {
+                       cf->can_id |= CAN_RTR_FLAG;
+               } else {
+                       for (i = 0; i < cf->can_dlc; i++)
+                               cf->data[i] = msg->msg.rx.data[i];
+               }
+
+               netif_rx(skb);
+
+               stats->rx_packets++;
+               stats->rx_bytes += cf->can_dlc;
+       }
+
+       return;
+}
+
+static void esd_usb2_tx_done_msg(struct esd_usb2_net_priv *priv,
+                                struct esd_usb2_msg *msg)
+{
+       struct net_device_stats *stats = &priv->netdev->stats;
+       struct net_device *netdev = priv->netdev;
+       struct esd_tx_urb_context *context;
+
+       if (!netif_device_present(netdev))
+               return;
+
+       context = &priv->tx_contexts[msg->msg.txdone.hnd & (MAX_TX_URBS - 1)];
+
+       if (!msg->msg.txdone.status) {
+               stats->tx_packets++;
+               stats->tx_bytes += context->dlc;
+               can_get_echo_skb(netdev, context->echo_index);
+       } else {
+               stats->tx_errors++;
+               can_free_echo_skb(netdev, context->echo_index);
+       }
+
+       /* Release context */
+       context->echo_index = MAX_TX_URBS;
+       atomic_dec(&priv->active_tx_jobs);
+
+       netif_wake_queue(netdev);
+}
+
+static void esd_usb2_read_bulk_callback(struct urb *urb)
+{
+       struct esd_usb2 *dev = urb->context;
+       int retval;
+       int pos = 0;
+       int i;
+
+       switch (urb->status) {
+       case 0: /* success */
+               break;
+
+       case -ENOENT:
+       case -ESHUTDOWN:
+               return;
+
+       default:
+               dev_info(dev->udev->dev.parent,
+                        "Rx URB aborted (%d)\n", urb->status);
+               goto resubmit_urb;
+       }
+
+       while (pos < urb->actual_length) {
+               struct esd_usb2_msg *msg;
+
+               msg = (struct esd_usb2_msg *)(urb->transfer_buffer + pos);
+
+               switch (msg->msg.hdr.cmd) {
+               case CMD_CAN_RX:
+                       esd_usb2_rx_can_msg(dev->nets[msg->msg.rx.net], msg);
+                       break;
+
+               case CMD_CAN_TX:
+                       esd_usb2_tx_done_msg(dev->nets[msg->msg.txdone.net],
+                                            msg);
+                       break;
+               }
+
+               pos += msg->msg.hdr.len << 2;
+
+               if (pos > urb->actual_length) {
+                       dev_err(dev->udev->dev.parent, "format error\n");
+                       break;
+               }
+       }
+
+resubmit_urb:
+       usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 1),
+                         urb->transfer_buffer, RX_BUFFER_SIZE,
+                         esd_usb2_read_bulk_callback, dev);
+
+       retval = usb_submit_urb(urb, GFP_ATOMIC);
+       if (retval == -ENODEV) {
+               for (i = 0; i < dev->net_count; i++) {
+                       if (dev->nets[i])
+                               netif_device_detach(dev->nets[i]->netdev);
+               }
+       } else if (retval) {
+               dev_err(dev->udev->dev.parent,
+                       "failed resubmitting read bulk urb: %d\n", retval);
+       }
+
+       return;
+}
+
+/*
+ * callback for bulk IN urb
+ */
+static void esd_usb2_write_bulk_callback(struct urb *urb)
+{
+       struct esd_tx_urb_context *context = urb->context;
+       struct esd_usb2_net_priv *priv;
+       struct esd_usb2 *dev;
+       struct net_device *netdev;
+       size_t size = sizeof(struct esd_usb2_msg);
+
+       WARN_ON(!context);
+
+       priv = context->priv;
+       netdev = priv->netdev;
+       dev = priv->usb2;
+
+       /* free up our allocated buffer */
+       usb_free_coherent(urb->dev, size,
+                         urb->transfer_buffer, urb->transfer_dma);
+
+       if (!netif_device_present(netdev))
+               return;
+
+       if (urb->status)
+               dev_info(netdev->dev.parent, "Tx URB aborted (%d)\n",
+                        urb->status);
+
+       netdev->trans_start = jiffies;
+}
+
+static ssize_t show_firmware(struct device *d,
+                            struct device_attribute *attr, char *buf)
+{
+       struct usb_interface *intf = to_usb_interface(d);
+       struct esd_usb2 *dev = usb_get_intfdata(intf);
+
+       return sprintf(buf, "%d.%d.%d\n",
+                      (dev->version >> 12) & 0xf,
+                      (dev->version >> 8) & 0xf,
+                      dev->version & 0xff);
+}
+static DEVICE_ATTR(firmware, S_IRUGO, show_firmware, NULL);
+
+static ssize_t show_hardware(struct device *d,
+                            struct device_attribute *attr, char *buf)
+{
+       struct usb_interface *intf = to_usb_interface(d);
+       struct esd_usb2 *dev = usb_get_intfdata(intf);
+
+       return sprintf(buf, "%d.%d.%d\n",
+                      (dev->version >> 28) & 0xf,
+                      (dev->version >> 24) & 0xf,
+                      (dev->version >> 16) & 0xff);
+}
+static DEVICE_ATTR(hardware, S_IRUGO, show_hardware, NULL);
+
+static ssize_t show_nets(struct device *d,
+                        struct device_attribute *attr, char *buf)
+{
+       struct usb_interface *intf = to_usb_interface(d);
+       struct esd_usb2 *dev = usb_get_intfdata(intf);
+
+       return sprintf(buf, "%d", dev->net_count);
+}
+static DEVICE_ATTR(nets, S_IRUGO, show_nets, NULL);
+
+static int esd_usb2_send_msg(struct esd_usb2 *dev, struct esd_usb2_msg *msg)
+{
+       int actual_length;
+
+       return usb_bulk_msg(dev->udev,
+                           usb_sndbulkpipe(dev->udev, 2),
+                           msg,
+                           msg->msg.hdr.len << 2,
+                           &actual_length,
+                           1000);
+}
+
+static int esd_usb2_wait_msg(struct esd_usb2 *dev,
+                            struct esd_usb2_msg *msg)
+{
+       int actual_length;
+
+       return usb_bulk_msg(dev->udev,
+                           usb_rcvbulkpipe(dev->udev, 1),
+                           msg,
+                           sizeof(*msg),
+                           &actual_length,
+                           1000);
+}
+
+static int esd_usb2_setup_rx_urbs(struct esd_usb2 *dev)
+{
+       int i, err = 0;
+
+       if (dev->rxinitdone)
+               return 0;
+
+       for (i = 0; i < MAX_RX_URBS; i++) {
+               struct urb *urb = NULL;
+               u8 *buf = NULL;
+
+               /* create a URB, and a buffer for it */
+               urb = usb_alloc_urb(0, GFP_KERNEL);
+               if (!urb) {
+                       dev_warn(dev->udev->dev.parent,
+                                "No memory left for URBs\n");
+                       err = -ENOMEM;
+                       break;
+               }
+
+               buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
+                                        &urb->transfer_dma);
+               if (!buf) {
+                       dev_warn(dev->udev->dev.parent,
+                                "No memory left for USB buffer\n");
+                       err = -ENOMEM;
+                       goto freeurb;
+               }
+
+               usb_fill_bulk_urb(urb, dev->udev,
+                                 usb_rcvbulkpipe(dev->udev, 1),
+                                 buf, RX_BUFFER_SIZE,
+                                 esd_usb2_read_bulk_callback, dev);
+               urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+               usb_anchor_urb(urb, &dev->rx_submitted);
+
+               err = usb_submit_urb(urb, GFP_KERNEL);
+               if (err) {
+                       usb_unanchor_urb(urb);
+                       usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
+                                         urb->transfer_dma);
+               }
+
+freeurb:
+               /* Drop reference, USB core will take care of freeing it */
+               usb_free_urb(urb);
+               if (err)
+                       break;
+       }
+
+       /* Did we submit any URBs */
+       if (i == 0) {
+               dev_err(dev->udev->dev.parent, "couldn't setup read URBs\n");
+               return err;
+       }
+
+       /* Warn if we've couldn't transmit all the URBs */
+       if (i < MAX_RX_URBS) {
+               dev_warn(dev->udev->dev.parent,
+                        "rx performance may be slow\n");
+       }
+
+       dev->rxinitdone = 1;
+       return 0;
+}
+
+/*
+ * Start interface
+ */
+static int esd_usb2_start(struct esd_usb2_net_priv *priv)
+{
+       struct esd_usb2 *dev = priv->usb2;
+       struct net_device *netdev = priv->netdev;
+       struct esd_usb2_msg msg;
+       int err, i;
+
+       /*
+        * Enable all IDs
+        * The IDADD message takes up to 64 32 bit bitmasks (2048 bits).
+        * Each bit represents one 11 bit CAN identifier. A set bit
+        * enables reception of the corresponding CAN identifier. A cleared
+        * bit disabled this identifier. An additional bitmask value
+        * following the CAN 2.0A bits is used to enable reception of
+        * extended CAN frames. Only the LSB of this final mask is checked
+        * for the complete 29 bit ID range. The IDADD message also allows
+        * filter configuration for an ID subset. In this case you can add
+        * the number of the starting bitmask (0..64) to the filter.option
+        * field followed by only some bitmasks.
+        */
+       msg.msg.hdr.cmd = CMD_IDADD;
+       msg.msg.hdr.len = 2 + ESD_MAX_ID_SEGMENT;
+       msg.msg.filter.net = priv->index;
+       msg.msg.filter.option = ESD_ID_ENABLE; /* start with segment 0 */
+       for (i = 0; i < ESD_MAX_ID_SEGMENT; i++)
+               msg.msg.filter.mask[i] = cpu_to_le32(0xffffffff);
+       /* enable 29bit extended IDs */
+       msg.msg.filter.mask[ESD_MAX_ID_SEGMENT] = cpu_to_le32(0x00000001);
+
+       err = esd_usb2_send_msg(dev, &msg);
+       if (err)
+               goto failed;
+
+       err = esd_usb2_setup_rx_urbs(dev);
+       if (err)
+               goto failed;
+
+       priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+       return 0;
+
+failed:
+       if (err == -ENODEV)
+               netif_device_detach(netdev);
+
+       dev_err(netdev->dev.parent, "couldn't start device: %d\n", err);
+
+       return err;
+}
+
+static void unlink_all_urbs(struct esd_usb2 *dev)
+{
+       struct esd_usb2_net_priv *priv;
+       int i;
+
+       usb_kill_anchored_urbs(&dev->rx_submitted);
+       for (i = 0; i < dev->net_count; i++) {
+               priv = dev->nets[i];
+               if (priv) {
+                       usb_kill_anchored_urbs(&priv->tx_submitted);
+                       atomic_set(&priv->active_tx_jobs, 0);
+
+                       for (i = 0; i < MAX_TX_URBS; i++)
+                               priv->tx_contexts[i].echo_index = MAX_TX_URBS;
+               }
+       }
+}
+
+static int esd_usb2_open(struct net_device *netdev)
+{
+       struct esd_usb2_net_priv *priv = netdev_priv(netdev);
+       int err;
+
+       /* common open */
+       err = open_candev(netdev);
+       if (err)
+               return err;
+
+       /* finally start device */
+       err = esd_usb2_start(priv);
+       if (err) {
+               dev_warn(netdev->dev.parent,
+                        "couldn't start device: %d\n", err);
+               close_candev(netdev);
+               return err;
+       }
+
+       priv->open_time = jiffies;
+
+       netif_start_queue(netdev);
+
+       return 0;
+}
+
+static netdev_tx_t esd_usb2_start_xmit(struct sk_buff *skb,
+                                     struct net_device *netdev)
+{
+       struct esd_usb2_net_priv *priv = netdev_priv(netdev);
+       struct esd_usb2 *dev = priv->usb2;
+       struct esd_tx_urb_context *context = NULL;
+       struct net_device_stats *stats = &netdev->stats;
+       struct can_frame *cf = (struct can_frame *)skb->data;
+       struct esd_usb2_msg *msg;
+       struct urb *urb;
+       u8 *buf;
+       int i, err;
+       int ret = NETDEV_TX_OK;
+       size_t size = sizeof(struct esd_usb2_msg);
+
+       if (can_dropped_invalid_skb(netdev, skb))
+               return NETDEV_TX_OK;
+
+       /* create a URB, and a buffer for it, and copy the data to the URB */
+       urb = usb_alloc_urb(0, GFP_ATOMIC);
+       if (!urb) {
+               dev_err(netdev->dev.parent, "No memory left for URBs\n");
+               stats->tx_dropped++;
+               dev_kfree_skb(skb);
+               goto nourbmem;
+       }
+
+       buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC,
+                                &urb->transfer_dma);
+       if (!buf) {
+               dev_err(netdev->dev.parent, "No memory left for USB buffer\n");
+               stats->tx_dropped++;
+               dev_kfree_skb(skb);
+               goto nobufmem;
+       }
+
+       msg = (struct esd_usb2_msg *)buf;
+
+       msg->msg.hdr.len = 3; /* minimal length */
+       msg->msg.hdr.cmd = CMD_CAN_TX;
+       msg->msg.tx.net = priv->index;
+       msg->msg.tx.dlc = cf->can_dlc;
+       msg->msg.tx.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
+
+       if (cf->can_id & CAN_RTR_FLAG)
+               msg->msg.tx.dlc |= ESD_RTR;
+
+       if (cf->can_id & CAN_EFF_FLAG)
+               msg->msg.tx.id |= cpu_to_le32(ESD_EXTID);
+
+       for (i = 0; i < cf->can_dlc; i++)
+               msg->msg.tx.data[i] = cf->data[i];
+
+       msg->msg.hdr.len += (cf->can_dlc + 3) >> 2;
+
+       for (i = 0; i < MAX_TX_URBS; i++) {
+               if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
+                       context = &priv->tx_contexts[i];
+                       break;
+               }
+       }
+
+       /*
+        * This may never happen.
+        */
+       if (!context) {
+               dev_warn(netdev->dev.parent, "couldn't find free context\n");
+               ret = NETDEV_TX_BUSY;
+               goto releasebuf;
+       }
+
+       context->priv = priv;
+       context->echo_index = i;
+       context->dlc = cf->can_dlc;
+
+       /* hnd must not be 0 - MSB is stripped in txdone handling */
+       msg->msg.tx.hnd = 0x80000000 | i; /* returned in TX done message */
+
+       usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
+                         msg->msg.hdr.len << 2,
+                         esd_usb2_write_bulk_callback, context);
+
+       urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+       usb_anchor_urb(urb, &priv->tx_submitted);
+
+       can_put_echo_skb(skb, netdev, context->echo_index);
+
+       atomic_inc(&priv->active_tx_jobs);
+
+       /* Slow down tx path */
+       if (atomic_read(&priv->active_tx_jobs) >= MAX_TX_URBS)
+               netif_stop_queue(netdev);
+
+       err = usb_submit_urb(urb, GFP_ATOMIC);
+       if (err) {
+               can_free_echo_skb(netdev, context->echo_index);
+
+               atomic_dec(&priv->active_tx_jobs);
+               usb_unanchor_urb(urb);
+
+               stats->tx_dropped++;
+
+               if (err == -ENODEV)
+                       netif_device_detach(netdev);
+               else
+                       dev_warn(netdev->dev.parent, "failed tx_urb %d\n", err);
+
+               goto releasebuf;
+       }
+
+       netdev->trans_start = jiffies;
+
+       /*
+        * Release our reference to this URB, the USB core will eventually free
+        * it entirely.
+        */
+       usb_free_urb(urb);
+
+       return NETDEV_TX_OK;
+
+releasebuf:
+       usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
+
+nobufmem:
+       usb_free_urb(urb);
+
+nourbmem:
+       return ret;
+}
+
+static int esd_usb2_close(struct net_device *netdev)
+{
+       struct esd_usb2_net_priv *priv = netdev_priv(netdev);
+       struct esd_usb2_msg msg;
+       int i;
+
+       /* Disable all IDs (see esd_usb2_start()) */
+       msg.msg.hdr.cmd = CMD_IDADD;
+       msg.msg.hdr.len = 2 + ESD_MAX_ID_SEGMENT;
+       msg.msg.filter.net = priv->index;
+       msg.msg.filter.option = ESD_ID_ENABLE; /* start with segment 0 */
+       for (i = 0; i <= ESD_MAX_ID_SEGMENT; i++)
+               msg.msg.filter.mask[i] = 0;
+       if (esd_usb2_send_msg(priv->usb2, &msg) < 0)
+               dev_err(netdev->dev.parent, "sending idadd message failed\n");
+
+       /* set CAN controller to reset mode */
+       msg.msg.hdr.len = 2;
+       msg.msg.hdr.cmd = CMD_SETBAUD;
+       msg.msg.setbaud.net = priv->index;
+       msg.msg.setbaud.rsvd = 0;
+       msg.msg.setbaud.baud = cpu_to_le32(ESD_USB2_NO_BAUDRATE);
+       if (esd_usb2_send_msg(priv->usb2, &msg) < 0)
+               dev_err(netdev->dev.parent, "sending setbaud message failed\n");
+
+       priv->can.state = CAN_STATE_STOPPED;
+
+       netif_stop_queue(netdev);
+
+       close_candev(netdev);
+
+       priv->open_time = 0;
+
+       return 0;
+}
+
+static const struct net_device_ops esd_usb2_netdev_ops = {
+       .ndo_open = esd_usb2_open,
+       .ndo_stop = esd_usb2_close,
+       .ndo_start_xmit = esd_usb2_start_xmit,
+};
+
+static struct can_bittiming_const esd_usb2_bittiming_const = {
+       .name = "esd_usb2",
+       .tseg1_min = ESD_USB2_TSEG1_MIN,
+       .tseg1_max = ESD_USB2_TSEG1_MAX,
+       .tseg2_min = ESD_USB2_TSEG2_MIN,
+       .tseg2_max = ESD_USB2_TSEG2_MAX,
+       .sjw_max = ESD_USB2_SJW_MAX,
+       .brp_min = ESD_USB2_BRP_MIN,
+       .brp_max = ESD_USB2_BRP_MAX,
+       .brp_inc = ESD_USB2_BRP_INC,
+};
+
+static int esd_usb2_set_bittiming(struct net_device *netdev)
+{
+       struct esd_usb2_net_priv *priv = netdev_priv(netdev);
+       struct can_bittiming *bt = &priv->can.bittiming;
+       struct esd_usb2_msg msg;
+       u32 canbtr;
+
+       canbtr = ESD_USB2_UBR;
+       canbtr |= (bt->brp - 1) & (ESD_USB2_BRP_MAX - 1);
+       canbtr |= ((bt->sjw - 1) & (ESD_USB2_SJW_MAX - 1))
+               << ESD_USB2_SJW_SHIFT;
+       canbtr |= ((bt->prop_seg + bt->phase_seg1 - 1)
+                  & (ESD_USB2_TSEG1_MAX - 1))
+               << ESD_USB2_TSEG1_SHIFT;
+       canbtr |= ((bt->phase_seg2 - 1) & (ESD_USB2_TSEG2_MAX - 1))
+               << ESD_USB2_TSEG2_SHIFT;
+       if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+               canbtr |= ESD_USB2_3_SAMPLES;
+
+       msg.msg.hdr.len = 2;
+       msg.msg.hdr.cmd = CMD_SETBAUD;
+       msg.msg.setbaud.net = priv->index;
+       msg.msg.setbaud.rsvd = 0;
+       msg.msg.setbaud.baud = cpu_to_le32(canbtr);
+
+       dev_info(netdev->dev.parent, "setting BTR=%#x\n", canbtr);
+
+       return esd_usb2_send_msg(priv->usb2, &msg);
+}
+
+static int esd_usb2_get_berr_counter(const struct net_device *netdev,
+                                    struct can_berr_counter *bec)
+{
+       struct esd_usb2_net_priv *priv = netdev_priv(netdev);
+
+       bec->txerr = priv->bec.txerr;
+       bec->rxerr = priv->bec.rxerr;
+
+       return 0;
+}
+
+static int esd_usb2_set_mode(struct net_device *netdev, enum can_mode mode)
+{
+       struct esd_usb2_net_priv *priv = netdev_priv(netdev);
+
+       if (!priv->open_time)
+               return -EINVAL;
+
+       switch (mode) {
+       case CAN_MODE_START:
+               netif_wake_queue(netdev);
+               break;
+
+       default:
+               return -EOPNOTSUPP;
+       }
+
+       return 0;
+}
+
+static int esd_usb2_probe_one_net(struct usb_interface *intf, int index)
+{
+       struct esd_usb2 *dev = usb_get_intfdata(intf);
+       struct net_device *netdev;
+       struct esd_usb2_net_priv *priv;
+       int err = 0;
+       int i;
+
+       netdev = alloc_candev(sizeof(*priv), MAX_TX_URBS);
+       if (!netdev) {
+               dev_err(&intf->dev, "couldn't alloc candev\n");
+               err = -ENOMEM;
+               goto done;
+       }
+
+       priv = netdev_priv(netdev);
+
+       init_usb_anchor(&priv->tx_submitted);
+       atomic_set(&priv->active_tx_jobs, 0);
+
+       for (i = 0; i < MAX_TX_URBS; i++)
+               priv->tx_contexts[i].echo_index = MAX_TX_URBS;
+
+       priv->usb2 = dev;
+       priv->netdev = netdev;
+       priv->index = index;
+
+       priv->can.state = CAN_STATE_STOPPED;
+       priv->can.clock.freq = ESD_USB2_CAN_CLOCK;
+       priv->can.bittiming_const = &esd_usb2_bittiming_const;
+       priv->can.do_set_bittiming = esd_usb2_set_bittiming;
+       priv->can.do_set_mode = esd_usb2_set_mode;
+       priv->can.do_get_berr_counter = esd_usb2_get_berr_counter;
+       priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
+
+       netdev->flags |= IFF_ECHO; /* we support local echo */
+
+       netdev->netdev_ops = &esd_usb2_netdev_ops;
+
+       SET_NETDEV_DEV(netdev, &intf->dev);
+
+       err = register_candev(netdev);
+       if (err) {
+               dev_err(&intf->dev,
+                       "couldn't register CAN device: %d\n", err);
+               free_candev(netdev);
+               err = -ENOMEM;
+               goto done;
+       }
+
+       dev->nets[index] = priv;
+       dev_info(netdev->dev.parent, "device %s registered\n", netdev->name);
+
+done:
+       return err;
+}
+
+/*
+ * probe function for new USB2 devices
+ *
+ * check version information and number of available
+ * CAN interfaces
+ */
+static int esd_usb2_probe(struct usb_interface *intf,
+                        const struct usb_device_id *id)
+{
+       struct esd_usb2 *dev;
+       struct esd_usb2_msg msg;
+       int i, err;
+
+       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+       if (!dev) {
+               err = -ENOMEM;
+               goto done;
+       }
+
+       dev->udev = interface_to_usbdev(intf);
+
+       init_usb_anchor(&dev->rx_submitted);
+
+       usb_set_intfdata(intf, dev);
+
+       /* query number of CAN interfaces (nets) */
+       msg.msg.hdr.cmd = CMD_VERSION;
+       msg.msg.hdr.len = 2;
+       msg.msg.version.rsvd = 0;
+       msg.msg.version.flags = 0;
+       msg.msg.version.drv_version = 0;
+
+       err = esd_usb2_send_msg(dev, &msg);
+       if (err < 0) {
+               dev_err(&intf->dev, "sending version message failed\n");
+               goto free_dev;
+       }
+
+       err = esd_usb2_wait_msg(dev, &msg);
+       if (err < 0) {
+               dev_err(&intf->dev, "no version message answer\n");
+               goto free_dev;
+       }
+
+       dev->net_count = (int)msg.msg.version_reply.nets;
+       dev->version = le32_to_cpu(msg.msg.version_reply.version);
+
+       if (device_create_file(&intf->dev, &dev_attr_firmware))
+               dev_err(&intf->dev,
+                       "Couldn't create device file for firmware\n");
+
+       if (device_create_file(&intf->dev, &dev_attr_hardware))
+               dev_err(&intf->dev,
+                       "Couldn't create device file for hardware\n");
+
+       if (device_create_file(&intf->dev, &dev_attr_nets))
+               dev_err(&intf->dev,
+                       "Couldn't create device file for nets\n");
+
+       /* do per device probing */
+       for (i = 0; i < dev->net_count; i++)
+               esd_usb2_probe_one_net(intf, i);
+
+       return 0;
+
+free_dev:
+       kfree(dev);
+done:
+       return err;
+}
+
+/*
+ * called by the usb core when the device is removed from the system
+ */
+static void esd_usb2_disconnect(struct usb_interface *intf)
+{
+       struct esd_usb2 *dev = usb_get_intfdata(intf);
+       struct net_device *netdev;
+       int i;
+
+       device_remove_file(&intf->dev, &dev_attr_firmware);
+       device_remove_file(&intf->dev, &dev_attr_hardware);
+       device_remove_file(&intf->dev, &dev_attr_nets);
+
+       usb_set_intfdata(intf, NULL);
+
+       if (dev) {
+               for (i = 0; i < dev->net_count; i++) {
+                       if (dev->nets[i]) {
+                               netdev = dev->nets[i]->netdev;
+                               unregister_netdev(netdev);
+                               free_candev(netdev);
+                       }
+               }
+               unlink_all_urbs(dev);
+       }
+}
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver esd_usb2_driver = {
+       .name = "esd_usb2",
+       .probe = esd_usb2_probe,
+       .disconnect = esd_usb2_disconnect,
+       .id_table = esd_usb2_table,
+};
+
+static int __init esd_usb2_init(void)
+{
+       int err;
+
+       /* register this driver with the USB subsystem */
+       err = usb_register(&esd_usb2_driver);
+
+       if (err) {
+               err("usb_register failed. Error number %d\n", err);
+               return err;
+       }
+
+       return 0;
+}
+module_init(esd_usb2_init);
+
+static void __exit esd_usb2_exit(void)
+{
+       /* deregister this driver with the USB subsystem */
+       usb_deregister(&esd_usb2_driver);
+}
+module_exit(esd_usb2_exit);