Initial import

1 files changed, 1034 insertions, 0 deletions

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
new file mode 100644
index 000000000..e9b1810d3
--- /dev/null
+++ b/drivers/net/can/dev.c
@@ -0,0 +1,1034 @@
+/*
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#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/skb.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,
+			      const struct can_bittiming_const *btc)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	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;
+	long rate;
+	u64 v64;
+
+	/* 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;
+		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,
+			      const struct can_bittiming_const *btc)
+{
+	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,
+			       const struct can_bittiming_const *btc)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	int tseg1, alltseg;
+	u64 brp64;
+
+	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,
+			     const struct can_bittiming_const *btc)
+{
+	int err;
+
+	/* Check if the CAN device has bit-timing parameters */
+	if (!btc)
+		return -EOPNOTSUPP;
+
+	/*
+	 * Depending on the given can_bittiming parameter structure the CAN
+	 * timing parameters are calculated based on the provided bitrate OR
+	 * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
+	 * provided directly which are then checked and fixed up.
+	 */
+	if (!bt->tq && bt->bitrate)
+		err = can_calc_bittiming(dev, bt, btc);
+	else if (bt->tq && !bt->bitrate)
+		err = can_fixup_bittiming(dev, bt, btc);
+	else
+		err = -EINVAL;
+
+	return err;
+}
+
+static void can_update_state_error_stats(struct net_device *dev,
+					 enum can_state new_state)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (new_state <= priv->state)
+		return;
+
+	switch (new_state) {
+	case CAN_STATE_ERROR_WARNING:
+		priv->can_stats.error_warning++;
+		break;
+	case CAN_STATE_ERROR_PASSIVE:
+		priv->can_stats.error_passive++;
+		break;
+	case CAN_STATE_BUS_OFF:
+		priv->can_stats.bus_off++;
+		break;
+	default:
+		break;
+	}
+}
+
+static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
+{
+	switch (state) {
+	case CAN_STATE_ERROR_ACTIVE:
+		return CAN_ERR_CRTL_ACTIVE;
+	case CAN_STATE_ERROR_WARNING:
+		return CAN_ERR_CRTL_TX_WARNING;
+	case CAN_STATE_ERROR_PASSIVE:
+		return CAN_ERR_CRTL_TX_PASSIVE;
+	default:
+		return 0;
+	}
+}
+
+static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
+{
+	switch (state) {
+	case CAN_STATE_ERROR_ACTIVE:
+		return CAN_ERR_CRTL_ACTIVE;
+	case CAN_STATE_ERROR_WARNING:
+		return CAN_ERR_CRTL_RX_WARNING;
+	case CAN_STATE_ERROR_PASSIVE:
+		return CAN_ERR_CRTL_RX_PASSIVE;
+	default:
+		return 0;
+	}
+}
+
+void can_change_state(struct net_device *dev, struct can_frame *cf,
+		      enum can_state tx_state, enum can_state rx_state)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	enum can_state new_state = max(tx_state, rx_state);
+
+	if (unlikely(new_state == priv->state)) {
+		netdev_warn(dev, "%s: oops, state did not change", __func__);
+		return;
+	}
+
+	netdev_dbg(dev, "New error state: %d\n", new_state);
+
+	can_update_state_error_stats(dev, new_state);
+	priv->state = new_state;
+
+	if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
+		cf->can_id |= CAN_ERR_BUSOFF;
+		return;
+	}
+
+	cf->can_id |= CAN_ERR_CRTL;
+	cf->data[1] |= tx_state >= rx_state ?
+		       can_tx_state_to_frame(dev, tx_state) : 0;
+	cf->data[1] |= tx_state <= rx_state ?
+		       can_rx_state_to_frame(dev, rx_state) : 0;
+}
+EXPORT_SYMBOL_GPL(can_change_state);
+
+/*
+ * 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 ||
+	    (skb->protocol != htons(ETH_P_CAN) &&
+	     skb->protocol != htons(ETH_P_CANFD))) {
+		kfree_skb(skb);
+		return;
+	}
+
+	if (!priv->echo_skb[idx]) {
+
+		skb = can_create_echo_skb(skb);
+		if (!skb)
+			return;
+
+		/* make settings for echo to reduce code in irq context */
+		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;
+
+		if (!(skb->tstamp.tv64))
+			__net_timestamp(skb);
+
+		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]) {
+		dev_kfree_skb_any(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);
+
+	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_skb_priv) +
+			       sizeof(struct can_frame));
+	if (unlikely(!skb))
+		return NULL;
+
+	__net_timestamp(skb);
+	skb->protocol = htons(ETH_P_CAN);
+	skb->pkt_type = PACKET_BROADCAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+
+	*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_canfd_skb(struct net_device *dev,
+				struct canfd_frame **cfd)
+{
+	struct sk_buff *skb;
+
+	skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
+			       sizeof(struct canfd_frame));
+	if (unlikely(!skb))
+		return NULL;
+
+	__net_timestamp(skb);
+	skb->protocol = htons(ETH_P_CANFD);
+	skb->pkt_type = PACKET_BROADCAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+
+	*cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
+	memset(*cfd, 0, sizeof(struct canfd_frame));
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(alloc_canfd_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", NET_NAME_UNKNOWN, 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);
+
+/*
+ * changing MTU and control mode for CAN/CANFD devices
+ */
+int can_change_mtu(struct net_device *dev, int new_mtu)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	/* Do not allow changing the MTU while running */
+	if (dev->flags & IFF_UP)
+		return -EBUSY;
+
+	/* allow change of MTU according to the CANFD ability of the device */
+	switch (new_mtu) {
+	case CAN_MTU:
+		priv->ctrlmode &= ~CAN_CTRLMODE_FD;
+		break;
+
+	case CANFD_MTU:
+		if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD))
+			return -EINVAL;
+
+		priv->ctrlmode |= CAN_CTRLMODE_FD;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	dev->mtu = new_mtu;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(can_change_mtu);
+
+/*
+ * 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.bitrate) {
+		netdev_err(dev, "bit-timing not yet defined\n");
+		return -EINVAL;
+	}
+
+	/* For CAN FD the data bitrate has to be >= the arbitration bitrate */
+	if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
+	    (!priv->data_bittiming.bitrate ||
+	     (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
+		netdev_err(dev, "incorrect/missing data bit-timing\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) },
+	[IFLA_CAN_DATA_BITTIMING]
+				= { .len = sizeof(struct can_bittiming) },
+	[IFLA_CAN_DATA_BITTIMING_CONST]
+				= { .len = sizeof(struct can_bittiming_const) },
+};
+
+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_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));
+		err = can_get_bittiming(dev, &bt, priv->bittiming_const);
+		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_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]);
+
+		/* check whether changed bits are allowed to be modified */
+		if (cm->mask & ~priv->ctrlmode_supported)
+			return -EOPNOTSUPP;
+
+		/* clear bits to be modified and copy the flag values */
+		priv->ctrlmode &= ~cm->mask;
+		priv->ctrlmode |= (cm->flags & cm->mask);
+
+		/* CAN_CTRLMODE_FD can only be set when driver supports FD */
+		if (priv->ctrlmode & CAN_CTRLMODE_FD)
+			dev->mtu = CANFD_MTU;
+		else
+			dev->mtu = CAN_MTU;
+	}
+
+	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;
+	}
+
+	if (data[IFLA_CAN_DATA_BITTIMING]) {
+		struct can_bittiming dbt;
+
+		/* Do not allow changing bittiming while running */
+		if (dev->flags & IFF_UP)
+			return -EBUSY;
+		memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
+		       sizeof(dbt));
+		err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
+		if (err)
+			return err;
+		memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
+
+		if (priv->do_set_data_bittiming) {
+			/* Finally, set the bit-timing registers */
+			err = priv->do_set_data_bittiming(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 = 0;
+
+	if (priv->bittiming.bitrate)				/* IFLA_CAN_BITTIMING */
+		size += nla_total_size(sizeof(struct can_bittiming));
+	if (priv->bittiming_const)				/* IFLA_CAN_BITTIMING_CONST */
+		size += nla_total_size(sizeof(struct can_bittiming_const));
+	size += nla_total_size(sizeof(struct can_clock));	/* IFLA_CAN_CLOCK */
+	size += nla_total_size(sizeof(u32));			/* IFLA_CAN_STATE */
+	size += nla_total_size(sizeof(struct can_ctrlmode));	/* IFLA_CAN_CTRLMODE */
+	size += nla_total_size(sizeof(u32));			/* IFLA_CAN_RESTART_MS */
+	if (priv->do_get_berr_counter)				/* IFLA_CAN_BERR_COUNTER */
+		size += nla_total_size(sizeof(struct can_berr_counter));
+	if (priv->data_bittiming.bitrate)			/* IFLA_CAN_DATA_BITTIMING */
+		size += nla_total_size(sizeof(struct can_bittiming));
+	if (priv->data_bittiming_const)				/* IFLA_CAN_DATA_BITTIMING_CONST */
+		size += nla_total_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 ((priv->bittiming.bitrate &&
+	     nla_put(skb, IFLA_CAN_BITTIMING,
+		     sizeof(priv->bittiming), &priv->bittiming)) ||
+
+	    (priv->bittiming_const &&
+	     nla_put(skb, IFLA_CAN_BITTIMING_CONST,
+		     sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
+
+	    nla_put(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock) ||
+	    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) ||
+
+	    (priv->do_get_berr_counter &&
+	     !priv->do_get_berr_counter(dev, &bec) &&
+	     nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
+
+	    (priv->data_bittiming.bitrate &&
+	     nla_put(skb, IFLA_CAN_DATA_BITTIMING,
+		     sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
+
+	    (priv->data_bittiming_const &&
+	     nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
+		     sizeof(*priv->data_bittiming_const),
+		     priv->data_bittiming_const)))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+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");