can: CAN Network device driver and Netlink interface

The CAN network device driver interface provides a generic interface to
setup, configure and monitor CAN network devices. It exports a set of
common data structures and functions, which all real CAN network device
drivers should use. Please have a look to the SJA1000 or MSCAN driver
to understand how to use them. The name of the module is can-dev.ko.

Furthermore, it adds a Netlink interface allowing to configure the CAN
device using the program "ip" from the iproute2 utility suite.

For further information please check "Documentation/networking/can.txt"

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 685 insertions, 0 deletions

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index 57def0d57371..77adb8ef6e4f 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -12,6 +12,29 @@ config CAN_VCAN
           This driver can also be built as a module.  If so, the module
           will be called vcan.
 
+config CAN_DEV
+        tristate "Platform CAN drivers with Netlink support"
+        depends on CAN
+        default Y
+        ---help---
+          Enables the common framework for platform CAN drivers with Netlink
+          support. This is the standard library for CAN drivers.
+          If unsure, say Y.
+
+config CAN_CALC_BITTIMING
+        bool "CAN bit-timing calculation"
+        depends on CAN_DEV
+        default Y
+        ---help---
+          If enabled, CAN bit-timing parameters will be calculated for the
+          bit-rate specified via Netlink argument "bitrate" when the device
+          get started. This works fine for the most common CAN controllers
+          with standard bit-rates but may fail for exotic bit-rates or CAN
+          source clock frequencies. Disabling saves some space, but then the
+          bit-timing parameters must be specified directly using the Netlink
+          arguments "tq", "prop_seg", "phase_seg1", "phase_seg2" and "sjw".
+          If unsure, say Y.
+
 config CAN_DEBUG_DEVICES
         bool "CAN devices debugging messages"
         depends on CAN
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index c4bead705cd9..6c865475cd88 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -3,3 +3,8 @@
 #
 
 obj-$(CONFIG_CAN_VCAN)          += vcan.o
+
+obj-$(CONFIG_CAN_DEV)           += can-dev.o
+can-dev-y                       := dev.o
+
+ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
new file mode 100644
index 000000000000..52b0e7d8901d
--- /dev/null
+++ b/drivers/net/can/dev.c
@@ -0,0 +1,657 @@
+/*
+ * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
+ * Copyright (C) 2006 Andrey Volkov, Varma Electronics
+ * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/netlink.h>
+#include <net/rtnetlink.h>
+
+#define MOD_DESC "CAN device driver interface"
+
+MODULE_DESCRIPTION(MOD_DESC);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
+
+#ifdef CONFIG_CAN_CALC_BITTIMING
+#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
+
+/*
+ * Bit-timing calculation derived from:
+ *
+ * Code based on LinCAN sources and H8S2638 project
+ * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
+ * Copyright 2005      Stanislav Marek
+ * email: pisa@cmp.felk.cvut.cz
+ *
+ * Calculates proper bit-timing parameters for a specified bit-rate
+ * and sample-point, which can then be used to set the bit-timing
+ * registers of the CAN controller. You can find more information
+ * in the header file linux/can/netlink.h.
+ */
+static int can_update_spt(const struct can_bittiming_const *btc,
+                          int sampl_pt, int tseg, int *tseg1, int *tseg2)
+{
+        *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
+        if (*tseg2 < btc->tseg2_min)
+                *tseg2 = btc->tseg2_min;
+        if (*tseg2 > btc->tseg2_max)
+                *tseg2 = btc->tseg2_max;
+        *tseg1 = tseg - *tseg2;
+        if (*tseg1 > btc->tseg1_max) {
+                *tseg1 = btc->tseg1_max;
+                *tseg2 = tseg - *tseg1;
+        }
+        return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
+}
+
+static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
+{
+        struct can_priv *priv = netdev_priv(dev);
+        const struct can_bittiming_const *btc = priv->bittiming_const;
+        long rate, best_rate = 0;
+        long best_error = 1000000000, error = 0;
+        int best_tseg = 0, best_brp = 0, brp = 0;
+        int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
+        int spt_error = 1000, spt = 0, sampl_pt;
+        u64 v64;
+
+        if (!priv->bittiming_const)
+                return -ENOTSUPP;
+
+        /* Use CIA recommended sample points */
+        if (bt->sample_point) {
+                sampl_pt = bt->sample_point;
+        } else {
+                if (bt->bitrate > 800000)
+                        sampl_pt = 750;
+                else if (bt->bitrate > 500000)
+                        sampl_pt = 800;
+                else
+                        sampl_pt = 875;
+        }
+
+        /* tseg even = round down, odd = round up */
+        for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
+             tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
+                tsegall = 1 + tseg / 2;
+                /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
+                brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
+                /* chose brp step which is possible in system */
+                brp = (brp / btc->brp_inc) * btc->brp_inc;
+                if ((brp < btc->brp_min) || (brp > btc->brp_max))
+                        continue;
+                rate = priv->clock.freq / (brp * tsegall);
+                error = bt->bitrate - rate;
+                /* tseg brp biterror */
+                if (error < 0)
+                        error = -error;
+                if (error > best_error)
+                        continue;
+                best_error = error;
+                if (error == 0) {
+                        spt = can_update_spt(btc, sampl_pt, tseg / 2,
+                                             &tseg1, &tseg2);
+                        error = sampl_pt - spt;
+                        if (error < 0)
+                                error = -error;
+                        if (error > spt_error)
+                                continue;
+                        spt_error = error;
+                }
+                best_tseg = tseg / 2;
+                best_brp = brp;
+                best_rate = rate;
+                if (error == 0)
+                        break;
+        }
+
+        if (best_error) {
+                /* Error in one-tenth of a percent */
+                error = (best_error * 1000) / bt->bitrate;
+                if (error > CAN_CALC_MAX_ERROR) {
+                        dev_err(dev->dev.parent,
+                                "bitrate error %ld.%ld%% too high\n",
+                                error / 10, error % 10);
+                        return -EDOM;
+                } else {
+                        dev_warn(dev->dev.parent, "bitrate error %ld.%ld%%\n",
+                                 error / 10, error % 10);
+                }
+        }
+
+        /* real sample point */
+        bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
+                                          &tseg1, &tseg2);
+
+        v64 = (u64)best_brp * 1000000000UL;
+        do_div(v64, priv->clock.freq);
+        bt->tq = (u32)v64;
+        bt->prop_seg = tseg1 / 2;
+        bt->phase_seg1 = tseg1 - bt->prop_seg;
+        bt->phase_seg2 = tseg2;
+        bt->sjw = 1;
+        bt->brp = best_brp;
+        /* real bit-rate */
+        bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
+
+        return 0;
+}
+#else /* !CONFIG_CAN_CALC_BITTIMING */
+static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
+{
+        dev_err(dev->dev.parent, "bit-timing calculation not available\n");
+        return -EINVAL;
+}
+#endif /* CONFIG_CAN_CALC_BITTIMING */
+
+/*
+ * Checks the validity of the specified bit-timing parameters prop_seg,
+ * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
+ * prescaler value brp. You can find more information in the header
+ * file linux/can/netlink.h.
+ */
+static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt)
+{
+        struct can_priv *priv = netdev_priv(dev);
+        const struct can_bittiming_const *btc = priv->bittiming_const;
+        int tseg1, alltseg;
+        u64 brp64;
+
+        if (!priv->bittiming_const)
+                return -ENOTSUPP;
+
+        tseg1 = bt->prop_seg + bt->phase_seg1;
+        if (!bt->sjw)
+                bt->sjw = 1;
+        if (bt->sjw > btc->sjw_max ||
+            tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
+            bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
+                return -ERANGE;
+
+        brp64 = (u64)priv->clock.freq * (u64)bt->tq;
+        if (btc->brp_inc > 1)
+                do_div(brp64, btc->brp_inc);
+        brp64 += 500000000UL - 1;
+        do_div(brp64, 1000000000UL); /* the practicable BRP */
+        if (btc->brp_inc > 1)
+                brp64 *= btc->brp_inc;
+        bt->brp = (u32)brp64;
+
+        if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
+                return -EINVAL;
+
+        alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
+        bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
+        bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
+
+        return 0;
+}
+
+int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt)
+{
+        struct can_priv *priv = netdev_priv(dev);
+        int err;
+
+        /* Check if the CAN device has bit-timing parameters */
+        if (priv->bittiming_const) {
+
+                /* Non-expert mode? Check if the bitrate has been pre-defined */
+                if (!bt->tq)
+                        /* Determine bit-timing parameters */
+                        err = can_calc_bittiming(dev, bt);
+                else
+                        /* Check bit-timing params and calculate proper brp */
+                        err = can_fixup_bittiming(dev, bt);
+                if (err)
+                        return err;
+        }
+
+        return 0;
+}
+
+/*
+ * Local echo of CAN messages
+ *
+ * CAN network devices *should* support a local echo functionality
+ * (see Documentation/networking/can.txt). To test the handling of CAN
+ * interfaces that do not support the local echo both driver types are
+ * implemented. In the case that the driver does not support the echo
+ * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
+ * to perform the echo as a fallback solution.
+ */
+static void can_flush_echo_skb(struct net_device *dev)
+{
+        struct can_priv *priv = netdev_priv(dev);
+        struct net_device_stats *stats = &dev->stats;
+        int i;
+
+        for (i = 0; i < CAN_ECHO_SKB_MAX; i++) {
+                if (priv->echo_skb[i]) {
+                        kfree_skb(priv->echo_skb[i]);
+                        priv->echo_skb[i] = NULL;
+                        stats->tx_dropped++;
+                        stats->tx_aborted_errors++;
+                }
+        }
+}
+
+/*
+ * Put the skb on the stack to be looped backed locally lateron
+ *
+ * The function is typically called in the start_xmit function
+ * of the device driver. The driver must protect access to
+ * priv->echo_skb, if necessary.
+ */
+void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx)
+{
+        struct can_priv *priv = netdev_priv(dev);
+
+        /* check flag whether this packet has to be looped back */
+        if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
+                kfree_skb(skb);
+                return;
+        }
+
+        if (!priv->echo_skb[idx]) {
+                struct sock *srcsk = skb->sk;
+
+                if (atomic_read(&skb->users) != 1) {
+                        struct sk_buff *old_skb = skb;
+
+                        skb = skb_clone(old_skb, GFP_ATOMIC);
+                        kfree_skb(old_skb);
+                        if (!skb)
+                                return;
+                } else
+                        skb_orphan(skb);
+
+                skb->sk = srcsk;
+
+                /* make settings for echo to reduce code in irq context */
+                skb->protocol = htons(ETH_P_CAN);
+                skb->pkt_type = PACKET_BROADCAST;
+                skb->ip_summed = CHECKSUM_UNNECESSARY;
+                skb->dev = dev;
+
+                /* save this skb for tx interrupt echo handling */
+                priv->echo_skb[idx] = skb;
+        } else {
+                /* locking problem with netif_stop_queue() ?? */
+                dev_err(dev->dev.parent, "%s: BUG! echo_skb is occupied!\n",
+                        __func__);
+                kfree_skb(skb);
+        }
+}
+EXPORT_SYMBOL_GPL(can_put_echo_skb);
+
+/*
+ * Get the skb from the stack and loop it back locally
+ *
+ * The function is typically called when the TX done interrupt
+ * is handled in the device driver. The driver must protect
+ * access to priv->echo_skb, if necessary.
+ */
+void can_get_echo_skb(struct net_device *dev, int idx)
+{
+        struct can_priv *priv = netdev_priv(dev);
+
+        if ((dev->flags & IFF_ECHO) && priv->echo_skb[idx]) {
+                netif_rx(priv->echo_skb[idx]);
+                priv->echo_skb[idx] = NULL;
+        }
+}
+EXPORT_SYMBOL_GPL(can_get_echo_skb);
+
+/*
+ * CAN device restart for bus-off recovery
+ */
+void can_restart(unsigned long data)
+{
+        struct net_device *dev = (struct net_device *)data;
+        struct can_priv *priv = netdev_priv(dev);
+        struct net_device_stats *stats = &dev->stats;
+        struct sk_buff *skb;
+        struct can_frame *cf;
+        int err;
+
+        BUG_ON(netif_carrier_ok(dev));
+
+        /*
+         * No synchronization needed because the device is bus-off and
+         * no messages can come in or go out.
+         */
+        can_flush_echo_skb(dev);
+
+        /* send restart message upstream */
+        skb = dev_alloc_skb(sizeof(struct can_frame));
+        if (skb == NULL) {
+                err = -ENOMEM;
+                goto out;
+        }
+        skb->dev = dev;
+        skb->protocol = htons(ETH_P_CAN);
+        cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
+        memset(cf, 0, sizeof(struct can_frame));
+        cf->can_id = CAN_ERR_FLAG | CAN_ERR_RESTARTED;
+        cf->can_dlc = CAN_ERR_DLC;
+
+        netif_rx(skb);
+
+        dev->last_rx = jiffies;
+        stats->rx_packets++;
+        stats->rx_bytes += cf->can_dlc;
+
+        dev_dbg(dev->dev.parent, "restarted\n");
+        priv->can_stats.restarts++;
+
+        /* Now restart the device */
+        err = priv->do_set_mode(dev, CAN_MODE_START);
+
+out:
+        netif_carrier_on(dev);
+        if (err)
+                dev_err(dev->dev.parent, "Error %d during restart", err);
+}
+
+int can_restart_now(struct net_device *dev)
+{
+        struct can_priv *priv = netdev_priv(dev);
+
+        /*
+         * A manual restart is only permitted if automatic restart is
+         * disabled and the device is in the bus-off state
+         */
+        if (priv->restart_ms)
+                return -EINVAL;
+        if (priv->state != CAN_STATE_BUS_OFF)
+                return -EBUSY;
+
+        /* Runs as soon as possible in the timer context */
+        mod_timer(&priv->restart_timer, jiffies);
+
+        return 0;
+}
+
+/*
+ * CAN bus-off
+ *
+ * This functions should be called when the device goes bus-off to
+ * tell the netif layer that no more packets can be sent or received.
+ * If enabled, a timer is started to trigger bus-off recovery.
+ */
+void can_bus_off(struct net_device *dev)
+{
+        struct can_priv *priv = netdev_priv(dev);
+
+        dev_dbg(dev->dev.parent, "bus-off\n");
+
+        netif_carrier_off(dev);
+        priv->can_stats.bus_off++;
+
+        if (priv->restart_ms)
+                mod_timer(&priv->restart_timer,
+                          jiffies + (priv->restart_ms * HZ) / 1000);
+}
+EXPORT_SYMBOL_GPL(can_bus_off);
+
+static void can_setup(struct net_device *dev)
+{
+        dev->type = ARPHRD_CAN;
+        dev->mtu = sizeof(struct can_frame);
+        dev->hard_header_len = 0;
+        dev->addr_len = 0;
+        dev->tx_queue_len = 10;
+
+        /* New-style flags. */
+        dev->flags = IFF_NOARP;
+        dev->features = NETIF_F_NO_CSUM;
+}
+
+/*
+ * Allocate and setup space for the CAN network device
+ */
+struct net_device *alloc_candev(int sizeof_priv)
+{
+        struct net_device *dev;
+        struct can_priv *priv;
+
+        dev = alloc_netdev(sizeof_priv, "can%d", can_setup);
+        if (!dev)
+                return NULL;
+
+        priv = netdev_priv(dev);
+
+        priv->state = CAN_STATE_STOPPED;
+
+        init_timer(&priv->restart_timer);
+
+        return dev;
+}
+EXPORT_SYMBOL_GPL(alloc_candev);
+
+/*
+ * Free space of the CAN network device
+ */
+void free_candev(struct net_device *dev)
+{
+        free_netdev(dev);
+}
+EXPORT_SYMBOL_GPL(free_candev);
+
+/*
+ * Common open function when the device gets opened.
+ *
+ * This function should be called in the open function of the device
+ * driver.
+ */
+int open_candev(struct net_device *dev)
+{
+        struct can_priv *priv = netdev_priv(dev);
+
+        if (!priv->bittiming.tq && !priv->bittiming.bitrate) {
+                dev_err(dev->dev.parent, "bit-timing not yet defined\n");
+                return -EINVAL;
+        }
+
+        setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
+
+        return 0;
+}
+EXPORT_SYMBOL(open_candev);
+
+/*
+ * Common close function for cleanup before the device gets closed.
+ *
+ * This function should be called in the close function of the device
+ * driver.
+ */
+void close_candev(struct net_device *dev)
+{
+        struct can_priv *priv = netdev_priv(dev);
+
+        if (del_timer_sync(&priv->restart_timer))
+                dev_put(dev);
+        can_flush_echo_skb(dev);
+}
+EXPORT_SYMBOL_GPL(close_candev);
+
+/*
+ * CAN netlink interface
+ */
+static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
+        [IFLA_CAN_STATE]        = { .type = NLA_U32 },
+        [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
+        [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
+        [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
+        [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
+        [IFLA_CAN_BITTIMING_CONST]
+                                = { .len = sizeof(struct can_bittiming_const) },
+        [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
+};
+
+static int can_changelink(struct net_device *dev,
+                          struct nlattr *tb[], struct nlattr *data[])
+{
+        struct can_priv *priv = netdev_priv(dev);
+        int err;
+
+        /* We need synchronization with dev->stop() */
+        ASSERT_RTNL();
+
+        if (data[IFLA_CAN_CTRLMODE]) {
+                struct can_ctrlmode *cm;
+
+                /* Do not allow changing controller mode while running */
+                if (dev->flags & IFF_UP)
+                        return -EBUSY;
+                cm = nla_data(data[IFLA_CAN_CTRLMODE]);
+                priv->ctrlmode &= ~cm->mask;
+                priv->ctrlmode |= cm->flags;
+        }
+
+        if (data[IFLA_CAN_BITTIMING]) {
+                struct can_bittiming bt;
+
+                /* Do not allow changing bittiming while running */
+                if (dev->flags & IFF_UP)
+                        return -EBUSY;
+                memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
+                if ((!bt.bitrate && !bt.tq) || (bt.bitrate && bt.tq))
+                        return -EINVAL;
+                err = can_get_bittiming(dev, &bt);
+                if (err)
+                        return err;
+                memcpy(&priv->bittiming, &bt, sizeof(bt));
+
+                if (priv->do_set_bittiming) {
+                        /* Finally, set the bit-timing registers */
+                        err = priv->do_set_bittiming(dev);
+                        if (err)
+                                return err;
+                }
+        }
+
+        if (data[IFLA_CAN_RESTART_MS]) {
+                /* Do not allow changing restart delay while running */
+                if (dev->flags & IFF_UP)
+                        return -EBUSY;
+                priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
+        }
+
+        if (data[IFLA_CAN_RESTART]) {
+                /* Do not allow a restart while not running */
+                if (!(dev->flags & IFF_UP))
+                        return -EINVAL;
+                err = can_restart_now(dev);
+                if (err)
+                        return err;
+        }
+
+        return 0;
+}
+
+static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+        struct can_priv *priv = netdev_priv(dev);
+        struct can_ctrlmode cm = {.flags = priv->ctrlmode};
+        enum can_state state = priv->state;
+
+        if (priv->do_get_state)
+                priv->do_get_state(dev, &state);
+        NLA_PUT_U32(skb, IFLA_CAN_STATE, state);
+        NLA_PUT(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm);
+        NLA_PUT_U32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms);
+        NLA_PUT(skb, IFLA_CAN_BITTIMING,
+                sizeof(priv->bittiming), &priv->bittiming);
+        NLA_PUT(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock);
+        if (priv->bittiming_const)
+                NLA_PUT(skb, IFLA_CAN_BITTIMING_CONST,
+                        sizeof(*priv->bittiming_const), priv->bittiming_const);
+
+        return 0;
+
+nla_put_failure:
+        return -EMSGSIZE;
+}
+
+static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
+{
+        struct can_priv *priv = netdev_priv(dev);
+
+        NLA_PUT(skb, IFLA_INFO_XSTATS,
+                sizeof(priv->can_stats), &priv->can_stats);
+
+        return 0;
+
+nla_put_failure:
+        return -EMSGSIZE;
+}
+
+static struct rtnl_link_ops can_link_ops __read_mostly = {
+        .kind           = "can",
+        .maxtype        = IFLA_CAN_MAX,
+        .policy         = can_policy,
+        .setup          = can_setup,
+        .changelink     = can_changelink,
+        .fill_info      = can_fill_info,
+        .fill_xstats    = can_fill_xstats,
+};
+
+/*
+ * Register the CAN network device
+ */
+int register_candev(struct net_device *dev)
+{
+        dev->rtnl_link_ops = &can_link_ops;
+        return register_netdev(dev);
+}
+EXPORT_SYMBOL_GPL(register_candev);
+
+/*
+ * Unregister the CAN network device
+ */
+void unregister_candev(struct net_device *dev)
+{
+        unregister_netdev(dev);
+}
+EXPORT_SYMBOL_GPL(unregister_candev);
+
+static __init int can_dev_init(void)
+{
+        int err;
+
+        err = rtnl_link_register(&can_link_ops);
+        if (!err)
+                printk(KERN_INFO MOD_DESC "\n");
+
+        return err;
+}
+module_init(can_dev_init);
+
+static __exit void can_dev_exit(void)
+{
+        rtnl_link_unregister(&can_link_ops);
+}
+module_exit(can_dev_exit);
+
+MODULE_ALIAS_RTNL_LINK("can");