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    /*
     * 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/slab.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 <linux/can/led.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>");
    
    /* CAN DLC to real data length conversion helpers */
    
    static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
    			     8, 12, 16, 20, 24, 32, 48, 64};
    
    /* get data length from can_dlc with sanitized can_dlc */
    u8 can_dlc2len(u8 can_dlc)
    {
    	return dlc2len[can_dlc & 0x0F];
    }
    EXPORT_SYMBOL_GPL(can_dlc2len);
    
    static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,		/* 0 - 8 */
    			     9, 9, 9, 9,			/* 9 - 12 */
    			     10, 10, 10, 10,			/* 13 - 16 */
    			     11, 11, 11, 11,			/* 17 - 20 */
    			     12, 12, 12, 12,			/* 21 - 24 */
    			     13, 13, 13, 13, 13, 13, 13, 13,	/* 25 - 32 */
    			     14, 14, 14, 14, 14, 14, 14, 14,	/* 33 - 40 */
    			     14, 14, 14, 14, 14, 14, 14, 14,	/* 41 - 48 */
    			     15, 15, 15, 15, 15, 15, 15, 15,	/* 49 - 56 */
    			     15, 15, 15, 15, 15, 15, 15, 15};	/* 57 - 64 */
    
    /* map the sanitized data length to an appropriate data length code */
    u8 can_len2dlc(u8 len)
    {
    	if (unlikely(len > 64))
    		return 0xF;
    
    	return len2dlc[len];
    }
    EXPORT_SYMBOL_GPL(can_len2dlc);
    
    #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) {
    			netdev_err(dev,
    				   "bitrate error %ld.%ld%% too high\n",
    				   error / 10, error % 10);
    			return -EDOM;
    		} else {
    			netdev_warn(dev, "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;
    
    	/* check for sjw user settings */
    	if (!bt->sjw || !btc->sjw_max)
    		bt->sjw = 1;
    	else {
    		/* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
    		if (bt->sjw > btc->sjw_max)
    			bt->sjw = btc->sjw_max;
    		/* bt->sjw must not be higher than tseg2 */
    		if (tseg2 < bt->sjw)
    			bt->sjw = tseg2;
    	}
    
    	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)
    {
    	netdev_err(dev, "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;
    }
    
    static 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 < priv->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,
    		      unsigned int idx)
    {
    	struct can_priv *priv = netdev_priv(dev);
    
    	BUG_ON(idx >= priv->echo_skb_max);
    
    	/* 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() ?? */
    		netdev_err(dev, "%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.
     */
    unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
    {
    	struct can_priv *priv = netdev_priv(dev);
    
    	BUG_ON(idx >= priv->echo_skb_max);
    
    	if (priv->echo_skb[idx]) {
    		struct sk_buff *skb = priv->echo_skb[idx];
    		struct can_frame *cf = (struct can_frame *)skb->data;
    		u8 dlc = cf->can_dlc;
    
    		netif_rx(priv->echo_skb[idx]);
    		priv->echo_skb[idx] = NULL;
    
    		return dlc;
    	}
    
    	return 0;
    }
    EXPORT_SYMBOL_GPL(can_get_echo_skb);
    
    /*
      * Remove the skb from the stack and free it.
      *
      * The function is typically called when TX failed.
      */
    void can_free_echo_skb(struct net_device *dev, unsigned int idx)
    {
    	struct can_priv *priv = netdev_priv(dev);
    
    	BUG_ON(idx >= priv->echo_skb_max);
    
    	if (priv->echo_skb[idx]) {
    		kfree_skb(priv->echo_skb[idx]);
    		priv->echo_skb[idx] = NULL;
    	}
    }
    EXPORT_SYMBOL_GPL(can_free_echo_skb);
    
    /*
     * CAN device restart for bus-off recovery
     */
    static 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 = alloc_can_err_skb(dev, &cf);
    	if (skb == NULL) {
    		err = -ENOMEM;
    		goto restart;
    	}
    	cf->can_id |= CAN_ERR_RESTARTED;
    
    	netif_rx(skb);
    
    	stats->rx_packets++;
    	stats->rx_bytes += cf->can_dlc;
    
    restart:
    	netdev_dbg(dev, "restarted\n");
    	priv->can_stats.restarts++;
    
    	/* Now restart the device */
    	err = priv->do_set_mode(dev, CAN_MODE_START);
    
    	netif_carrier_on(dev);
    	if (err)
    		netdev_err(dev, "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);
    
    	netdev_dbg(dev, "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 = CAN_MTU;
    	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_HW_CSUM;
    }
    
    struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
    {
    	struct sk_buff *skb;
    
    	skb = netdev_alloc_skb(dev, sizeof(struct can_frame));
    	if (unlikely(!skb))
    		return NULL;
    
    	skb->protocol = htons(ETH_P_CAN);
    	skb->pkt_type = PACKET_BROADCAST;
    	skb->ip_summed = CHECKSUM_UNNECESSARY;
    	*cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
    	memset(*cf, 0, sizeof(struct can_frame));
    
    	return skb;
    }
    EXPORT_SYMBOL_GPL(alloc_can_skb);
    
    struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
    {
    	struct sk_buff *skb;
    
    	skb = alloc_can_skb(dev, cf);
    	if (unlikely(!skb))
    		return NULL;
    
    	(*cf)->can_id = CAN_ERR_FLAG;
    	(*cf)->can_dlc = CAN_ERR_DLC;
    
    	return skb;
    }
    EXPORT_SYMBOL_GPL(alloc_can_err_skb);
    
    /*
     * Allocate and setup space for the CAN network device
     */
    struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
    {
    	struct net_device *dev;
    	struct can_priv *priv;
    	int size;
    
    	if (echo_skb_max)
    		size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
    			echo_skb_max * sizeof(struct sk_buff *);
    	else
    		size = sizeof_priv;
    
    	dev = alloc_netdev(size, "can%d", can_setup);
    	if (!dev)
    		return NULL;
    
    	priv = netdev_priv(dev);
    
    	if (echo_skb_max) {
    		priv->echo_skb_max = echo_skb_max;
    		priv->echo_skb = (void *)priv +
    			ALIGN(sizeof_priv, sizeof(struct sk_buff *));
    	}
    
    	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) {
    		netdev_err(dev, "bit-timing not yet defined\n");
    		return -EINVAL;
    	}
    
    	/* Switch carrier on if device was stopped while in bus-off state */
    	if (!netif_carrier_ok(dev))
    		netif_carrier_on(dev);
    
    	setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
    
    	return 0;
    }
    EXPORT_SYMBOL_GPL(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);
    
    	del_timer_sync(&priv->restart_timer);
    	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) },
    	[IFLA_CAN_BERR_COUNTER]	= { .len = sizeof(struct can_berr_counter) },
    };
    
    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]);
    		if (cm->flags & ~priv->ctrlmode_supported)
    			return -EOPNOTSUPP;
    		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 size_t can_get_size(const struct net_device *dev)
    {
    	struct can_priv *priv = netdev_priv(dev);
    	size_t size;
    
    	size = nla_total_size(sizeof(u32));   /* IFLA_CAN_STATE */
    	size += sizeof(struct can_ctrlmode);  /* IFLA_CAN_CTRLMODE */
    	size += nla_total_size(sizeof(u32));  /* IFLA_CAN_RESTART_MS */
    	size += sizeof(struct can_bittiming); /* IFLA_CAN_BITTIMING */
    	size += sizeof(struct can_clock);     /* IFLA_CAN_CLOCK */
    	if (priv->do_get_berr_counter)        /* IFLA_CAN_BERR_COUNTER */
    		size += sizeof(struct can_berr_counter);
    	if (priv->bittiming_const)	      /* IFLA_CAN_BITTIMING_CONST */
    		size += sizeof(struct can_bittiming_const);
    
    	return size;
    }
    
    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};
    	struct can_berr_counter bec;
    	enum can_state state = priv->state;
    
    	if (priv->do_get_state)
    		priv->do_get_state(dev, &state);
    	if (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) ||
    	    (priv->do_get_berr_counter &&
    	     !priv->do_get_berr_counter(dev, &bec) &&
    	     nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
    	    (priv->bittiming_const &&
    	     nla_put(skb, IFLA_CAN_BITTIMING_CONST,
    		     sizeof(*priv->bittiming_const), priv->bittiming_const)))
    		goto nla_put_failure;
    	return 0;
    
    nla_put_failure:
    	return -EMSGSIZE;
    }
    
    static size_t can_get_xstats_size(const struct net_device *dev)
    {
    	return sizeof(struct can_device_stats);
    }
    
    static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
    {
    	struct can_priv *priv = netdev_priv(dev);
    
    	if (nla_put(skb, IFLA_INFO_XSTATS,
    		    sizeof(priv->can_stats), &priv->can_stats))
    		goto nla_put_failure;
    	return 0;
    
    nla_put_failure:
    	return -EMSGSIZE;
    }
    
    static int can_newlink(struct net *src_net, struct net_device *dev,
    		       struct nlattr *tb[], struct nlattr *data[])
    {
    	return -EOPNOTSUPP;
    }
    
    static struct rtnl_link_ops can_link_ops __read_mostly = {
    	.kind		= "can",
    	.maxtype	= IFLA_CAN_MAX,
    	.policy		= can_policy,
    	.setup		= can_setup,
    	.newlink	= can_newlink,
    	.changelink	= can_changelink,
    	.get_size	= can_get_size,
    	.fill_info	= can_fill_info,
    	.get_xstats_size = can_get_xstats_size,
    	.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);
    
    /*
     * Test if a network device is a candev based device
     * and return the can_priv* if so.
     */
    struct can_priv *safe_candev_priv(struct net_device *dev)
    {
    	if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
    		return NULL;
    
    	return netdev_priv(dev);
    }
    EXPORT_SYMBOL_GPL(safe_candev_priv);
    
    static __init int can_dev_init(void)
    {
    	int err;
    
    	can_led_notifier_init();
    
    	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);
    
    	can_led_notifier_exit();
    }
    module_exit(can_dev_exit);
    
    MODULE_ALIAS_RTNL_LINK("can");