drivers/net/can/dev/rx-offload.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2014      Protonic Holland,
  *                         David Jander
  * Copyright (C) 2014-2021, 2023 Pengutronix,
  *                         Marc Kleine-Budde <kernel@pengutronix.de>
  */

 #include <linux/can/dev.h>
 #include <linux/can/rx-offload.h>

 struct can_rx_offload_cb {
 	u32 timestamp;
 };

 static inline struct can_rx_offload_cb *
 can_rx_offload_get_cb(struct sk_buff *skb)
 {
 	BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb));

 	return (struct can_rx_offload_cb *)skb->cb;
 }

 static inline bool
 can_rx_offload_le(struct can_rx_offload *offload,
 		  unsigned int a, unsigned int b)
 {
 	if (offload->inc)
 		return a <= b;
 	else
 		return a >= b;
 }

 static inline unsigned int
 can_rx_offload_inc(struct can_rx_offload *offload, unsigned int *val)
 {
 	if (offload->inc)
 		return (*val)++;
 	else
 		return (*val)--;
 }

 static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
 {
 	struct can_rx_offload *offload = container_of(napi,
 						      struct can_rx_offload,
 						      napi);
 	struct net_device *dev = offload->dev;
 	struct net_device_stats *stats = &dev->stats;
 	struct sk_buff *skb;
 	int work_done = 0;

 	while ((work_done < quota) &&
 	       (skb = skb_dequeue(&offload->skb_queue))) {
 		struct can_frame *cf = (struct can_frame *)skb->data;

 		work_done++;
 		if (!(cf->can_id & CAN_ERR_FLAG)) {
 			stats->rx_packets++;
 			if (!(cf->can_id & CAN_RTR_FLAG))
 				stats->rx_bytes += cf->len;
 		}
 		netif_receive_skb(skb);
 	}

 	if (work_done < quota) {
 		napi_complete_done(napi, work_done);

 		/* Check if there was another interrupt */
 		if (!skb_queue_empty(&offload->skb_queue))
 			napi_reschedule(&offload->napi);
 	}

 	return work_done;
 }

 static inline void
 __skb_queue_add_sort(struct sk_buff_head *head, struct sk_buff *new,
 		     int (*compare)(struct sk_buff *a, struct sk_buff *b))
 {
 	struct sk_buff *pos, *insert = NULL;

 	skb_queue_reverse_walk(head, pos) {
 		const struct can_rx_offload_cb *cb_pos, *cb_new;

 		cb_pos = can_rx_offload_get_cb(pos);
 		cb_new = can_rx_offload_get_cb(new);

 		netdev_dbg(new->dev,
 			   "%s: pos=0x%08x, new=0x%08x, diff=%10d, queue_len=%d\n",
 			   __func__,
 			   cb_pos->timestamp, cb_new->timestamp,
 			   cb_new->timestamp - cb_pos->timestamp,
 			   skb_queue_len(head));

 		if (compare(pos, new) < 0)
 			continue;
 		insert = pos;
 		break;
 	}
 	if (!insert)
 		__skb_queue_head(head, new);
 	else
 		__skb_queue_after(head, insert, new);
 }

 static int can_rx_offload_compare(struct sk_buff *a, struct sk_buff *b)
 {
 	const struct can_rx_offload_cb *cb_a, *cb_b;

 	cb_a = can_rx_offload_get_cb(a);
 	cb_b = can_rx_offload_get_cb(b);

 	/* Subtract two u32 and return result as int, to keep
 	 * difference steady around the u32 overflow.
 	 */
 	return cb_b->timestamp - cb_a->timestamp;
 }

 /**
  * can_rx_offload_offload_one() - Read one CAN frame from HW
  * @offload: pointer to rx_offload context
  * @n: number of mailbox to read
  *
  * The task of this function is to read a CAN frame from mailbox @n
  * from the device and return the mailbox's content as a struct
  * sk_buff.
  *
  * If the struct can_rx_offload::skb_queue exceeds the maximal queue
  * length (struct can_rx_offload::skb_queue_len_max) or no skb can be
  * allocated, the mailbox contents is discarded by reading it into an
  * overflow buffer. This way the mailbox is marked as free by the
  * driver.
  *
  * Return: A pointer to skb containing the CAN frame on success.
  *
  *         NULL if the mailbox @n is empty.
  *
  *         ERR_PTR() in case of an error
  */
 static struct sk_buff *
 can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
 {
 	struct sk_buff *skb;
 	struct can_rx_offload_cb *cb;
 	bool drop = false;
 	u32 timestamp;

 	/* If queue is full drop frame */
 	if (unlikely(skb_queue_len(&offload->skb_queue) >
 		     offload->skb_queue_len_max))
 		drop = true;

 	skb = offload->mailbox_read(offload, n, &timestamp, drop);
 	/* Mailbox was empty. */
 	if (unlikely(!skb))
 		return NULL;

 	/* There was a problem reading the mailbox, propagate
 	 * error value.
 	 */
 	if (IS_ERR(skb)) {
 		offload->dev->stats.rx_dropped++;
 		offload->dev->stats.rx_fifo_errors++;

 		return skb;
 	}

 	/* Mailbox was read. */
 	cb = can_rx_offload_get_cb(skb);
 	cb->timestamp = timestamp;

 	return skb;
 }

 int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload,
 					 u64 pending)
 {
 	unsigned int i;
 	int received = 0;

 	for (i = offload->mb_first;
 	     can_rx_offload_le(offload, i, offload->mb_last);
 	     can_rx_offload_inc(offload, &i)) {
 		struct sk_buff *skb;

 		if (!(pending & BIT_ULL(i)))
 			continue;

 		skb = can_rx_offload_offload_one(offload, i);
 		if (IS_ERR_OR_NULL(skb))
 			continue;

 		__skb_queue_add_sort(&offload->skb_irq_queue, skb,
 				     can_rx_offload_compare);
 		received++;
 	}

 	return received;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_timestamp);

 int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload)
 {
 	struct sk_buff *skb;
 	int received = 0;

 	while (1) {
 		skb = can_rx_offload_offload_one(offload, 0);
 		if (IS_ERR(skb))
 			continue;
 		if (!skb)
 			break;

 		__skb_queue_tail(&offload->skb_irq_queue, skb);
 		received++;
 	}

 	return received;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);

 int can_rx_offload_queue_timestamp(struct can_rx_offload *offload,
 				   struct sk_buff *skb, u32 timestamp)
 {
 	struct can_rx_offload_cb *cb;

 	if (skb_queue_len(&offload->skb_queue) >
 	    offload->skb_queue_len_max) {
 		dev_kfree_skb_any(skb);
 		return -ENOBUFS;
 	}

 	cb = can_rx_offload_get_cb(skb);
 	cb->timestamp = timestamp;

 	__skb_queue_add_sort(&offload->skb_irq_queue, skb,
 			     can_rx_offload_compare);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_queue_timestamp);

 unsigned int
 can_rx_offload_get_echo_skb_queue_timestamp(struct can_rx_offload *offload,
 					    unsigned int idx, u32 timestamp,
 					    unsigned int *frame_len_ptr)
 {
 	struct net_device *dev = offload->dev;
 	struct net_device_stats *stats = &dev->stats;
 	struct sk_buff *skb;
 	unsigned int len;
 	int err;

 	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
 	if (!skb)
 		return 0;

 	err = can_rx_offload_queue_timestamp(offload, skb, timestamp);
 	if (err) {
 		stats->rx_errors++;
 		stats->tx_fifo_errors++;
 	}

 	return len;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb_queue_timestamp);

 int can_rx_offload_queue_tail(struct can_rx_offload *offload,
 			      struct sk_buff *skb)
 {
 	if (skb_queue_len(&offload->skb_queue) >
 	    offload->skb_queue_len_max) {
 		dev_kfree_skb_any(skb);
 		return -ENOBUFS;
 	}

 	__skb_queue_tail(&offload->skb_irq_queue, skb);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);

 unsigned int
 can_rx_offload_get_echo_skb_queue_tail(struct can_rx_offload *offload,
 				       unsigned int idx,
 				       unsigned int *frame_len_ptr)
 {
 	struct net_device *dev = offload->dev;
 	struct net_device_stats *stats = &dev->stats;
 	struct sk_buff *skb;
 	unsigned int len;
 	int err;

 	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
 	if (!skb)
 		return 0;

 	err = can_rx_offload_queue_tail(offload, skb);
 	if (err) {
 		stats->rx_errors++;
 		stats->tx_fifo_errors++;
 	}

 	return len;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb_queue_tail);

 void can_rx_offload_irq_finish(struct can_rx_offload *offload)
 {
 	unsigned long flags;
 	int queue_len;

 	if (skb_queue_empty_lockless(&offload->skb_irq_queue))
 		return;

 	spin_lock_irqsave(&offload->skb_queue.lock, flags);
 	skb_queue_splice_tail_init(&offload->skb_irq_queue, &offload->skb_queue);
 	spin_unlock_irqrestore(&offload->skb_queue.lock, flags);

 	queue_len = skb_queue_len(&offload->skb_queue);
 	if (queue_len > offload->skb_queue_len_max / 8)
 		netdev_dbg(offload->dev, "%s: queue_len=%d\n",
 			   __func__, queue_len);

 	napi_schedule(&offload->napi);
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_irq_finish);

 void can_rx_offload_threaded_irq_finish(struct can_rx_offload *offload)
 {
 	unsigned long flags;
 	int queue_len;

 	if (skb_queue_empty_lockless(&offload->skb_irq_queue))
 		return;

 	spin_lock_irqsave(&offload->skb_queue.lock, flags);
 	skb_queue_splice_tail_init(&offload->skb_irq_queue, &offload->skb_queue);
 	spin_unlock_irqrestore(&offload->skb_queue.lock, flags);

 	queue_len = skb_queue_len(&offload->skb_queue);
 	if (queue_len > offload->skb_queue_len_max / 8)
 		netdev_dbg(offload->dev, "%s: queue_len=%d\n",
 			   __func__, queue_len);

 	local_bh_disable();
 	napi_schedule(&offload->napi);
 	local_bh_enable();
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_threaded_irq_finish);

 static int can_rx_offload_init_queue(struct net_device *dev,
 				     struct can_rx_offload *offload,
 				     unsigned int weight)
 {
 	offload->dev = dev;

 	/* Limit queue len to 4x the weight (rounded to next power of two) */
 	offload->skb_queue_len_max = 2 << fls(weight);
 	offload->skb_queue_len_max *= 4;
 	skb_queue_head_init(&offload->skb_queue);
 	__skb_queue_head_init(&offload->skb_irq_queue);

 	netif_napi_add_weight(dev, &offload->napi, can_rx_offload_napi_poll,
 			      weight);

 	dev_dbg(dev->dev.parent, "%s: skb_queue_len_max=%d\n",
 		__func__, offload->skb_queue_len_max);

 	return 0;
 }

 int can_rx_offload_add_timestamp(struct net_device *dev,
 				 struct can_rx_offload *offload)
 {
 	unsigned int weight;

 	if (offload->mb_first > BITS_PER_LONG_LONG ||
 	    offload->mb_last > BITS_PER_LONG_LONG || !offload->mailbox_read)
 		return -EINVAL;

 	if (offload->mb_first < offload->mb_last) {
 		offload->inc = true;
 		weight = offload->mb_last - offload->mb_first;
 	} else {
 		offload->inc = false;
 		weight = offload->mb_first - offload->mb_last;
 	}

 	return can_rx_offload_init_queue(dev, offload, weight);
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp);

 int can_rx_offload_add_fifo(struct net_device *dev,
 			    struct can_rx_offload *offload, unsigned int weight)
 {
 	if (!offload->mailbox_read)
 		return -EINVAL;

 	return can_rx_offload_init_queue(dev, offload, weight);
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo);

 int can_rx_offload_add_manual(struct net_device *dev,
 			      struct can_rx_offload *offload,
 			      unsigned int weight)
 {
 	if (offload->mailbox_read)
 		return -EINVAL;

 	return can_rx_offload_init_queue(dev, offload, weight);
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_add_manual);

 void can_rx_offload_enable(struct can_rx_offload *offload)
 {
 	napi_enable(&offload->napi);
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_enable);

 void can_rx_offload_del(struct can_rx_offload *offload)
 {
 	netif_napi_del(&offload->napi);
 	skb_queue_purge(&offload->skb_queue);
 	__skb_queue_purge(&offload->skb_irq_queue);
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_del);
	// SPDX-License-Identifier: GPL-2.0-only
	/* Copyright (c) 2014 Protonic Holland,
	* David Jander
	* Copyright (C) 2014-2021, 2023 Pengutronix,
	* Marc Kleine-Budde <kernel@pengutronix.de>
	*/

	#include <linux/can/dev.h>
	#include <linux/can/rx-offload.h>

	struct can_rx_offload_cb {
	u32 timestamp;
	};

	static inline struct can_rx_offload_cb *
	can_rx_offload_get_cb(struct sk_buff *skb)
	{
	BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb));

	return (struct can_rx_offload_cb *)skb->cb;
	}

	static inline bool
	can_rx_offload_le(struct can_rx_offload *offload,
	unsigned int a, unsigned int b)
	{
	if (offload->inc)
	return a <= b;
	else
	return a >= b;
	}

	static inline unsigned int
	can_rx_offload_inc(struct can_rx_offload offload, unsigned int val)
	{
	if (offload->inc)
	return (*val)++;
	else
	return (*val)--;
	}

	static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
	{
	struct can_rx_offload *offload = container_of(napi,
	struct can_rx_offload,
	napi);
	struct net_device *dev = offload->dev;
	struct net_device_stats *stats = &dev->stats;
	struct sk_buff *skb;
	int work_done = 0;

	while ((work_done < quota) &&
	(skb = skb_dequeue(&offload->skb_queue))) {
	struct can_frame cf = (struct can_frame )skb->data;

	work_done++;
	if (!(cf->can_id & CAN_ERR_FLAG)) {
	stats->rx_packets++;
	if (!(cf->can_id & CAN_RTR_FLAG))
	stats->rx_bytes += cf->len;
	}
	netif_receive_skb(skb);
	}

	if (work_done < quota) {
	napi_complete_done(napi, work_done);

	/* Check if there was another interrupt */
	if (!skb_queue_empty(&offload->skb_queue))
	napi_reschedule(&offload->napi);
	}

	return work_done;
	}

	static inline void
	__skb_queue_add_sort(struct sk_buff_head head, struct sk_buff new,
	int (compare)(struct sk_buff a, struct sk_buff *b))
	{
	struct sk_buff pos, insert = NULL;

	skb_queue_reverse_walk(head, pos) {
	const struct can_rx_offload_cb cb_pos, cb_new;

	cb_pos = can_rx_offload_get_cb(pos);
	cb_new = can_rx_offload_get_cb(new);

	netdev_dbg(new->dev,
	"%s: pos=0x%08x, new=0x%08x, diff=%10d, queue_len=%d\n",
	__func__,
	cb_pos->timestamp, cb_new->timestamp,
	cb_new->timestamp - cb_pos->timestamp,
	skb_queue_len(head));

	if (compare(pos, new) < 0)
	continue;
	insert = pos;
	break;
	}
	if (!insert)
	__skb_queue_head(head, new);
	else
	__skb_queue_after(head, insert, new);
	}

	static int can_rx_offload_compare(struct sk_buff a, struct sk_buff b)
	{
	const struct can_rx_offload_cb cb_a, cb_b;

	cb_a = can_rx_offload_get_cb(a);
	cb_b = can_rx_offload_get_cb(b);

	/* Subtract two u32 and return result as int, to keep
	* difference steady around the u32 overflow.
	*/
	return cb_b->timestamp - cb_a->timestamp;
	}

	/**
	* can_rx_offload_offload_one() - Read one CAN frame from HW
	* @offload: pointer to rx_offload context
	* @n: number of mailbox to read
	*
	* The task of this function is to read a CAN frame from mailbox @n
	* from the device and return the mailbox's content as a struct
	* sk_buff.
	*
	* If the struct can_rx_offload::skb_queue exceeds the maximal queue
	* length (struct can_rx_offload::skb_queue_len_max) or no skb can be
	* allocated, the mailbox contents is discarded by reading it into an
	* overflow buffer. This way the mailbox is marked as free by the
	* driver.
	*
	* Return: A pointer to skb containing the CAN frame on success.
	*
	* NULL if the mailbox @n is empty.
	*
	* ERR_PTR() in case of an error
	*/
	static struct sk_buff *
	can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
	{
	struct sk_buff *skb;
	struct can_rx_offload_cb *cb;
	bool drop = false;
	u32 timestamp;

	/* If queue is full drop frame */
	if (unlikely(skb_queue_len(&offload->skb_queue) >
	offload->skb_queue_len_max))
	drop = true;

	skb = offload->mailbox_read(offload, n, &timestamp, drop);
	/* Mailbox was empty. */
	if (unlikely(!skb))
	return NULL;

	/* There was a problem reading the mailbox, propagate
	* error value.
	*/
	if (IS_ERR(skb)) {
	offload->dev->stats.rx_dropped++;
	offload->dev->stats.rx_fifo_errors++;

	return skb;
	}

	/* Mailbox was read. */
	cb = can_rx_offload_get_cb(skb);
	cb->timestamp = timestamp;

	return skb;
	}

	int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload,
	u64 pending)
	{
	unsigned int i;
	int received = 0;

	for (i = offload->mb_first;
	can_rx_offload_le(offload, i, offload->mb_last);
	can_rx_offload_inc(offload, &i)) {
	struct sk_buff *skb;

	if (!(pending & BIT_ULL(i)))
	continue;

	skb = can_rx_offload_offload_one(offload, i);
	if (IS_ERR_OR_NULL(skb))
	continue;

	__skb_queue_add_sort(&offload->skb_irq_queue, skb,
	can_rx_offload_compare);
	received++;
	}

	return received;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_timestamp);

	int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload)
	{
	struct sk_buff *skb;
	int received = 0;

	while (1) {
	skb = can_rx_offload_offload_one(offload, 0);
	if (IS_ERR(skb))
	continue;
	if (!skb)
	break;

	__skb_queue_tail(&offload->skb_irq_queue, skb);
	received++;
	}

	return received;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);

	int can_rx_offload_queue_timestamp(struct can_rx_offload *offload,
	struct sk_buff *skb, u32 timestamp)
	{
	struct can_rx_offload_cb *cb;

	if (skb_queue_len(&offload->skb_queue) >
	offload->skb_queue_len_max) {
	dev_kfree_skb_any(skb);
	return -ENOBUFS;
	}

	cb = can_rx_offload_get_cb(skb);
	cb->timestamp = timestamp;

	__skb_queue_add_sort(&offload->skb_irq_queue, skb,
	can_rx_offload_compare);

	return 0;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_queue_timestamp);

	unsigned int
	can_rx_offload_get_echo_skb_queue_timestamp(struct can_rx_offload *offload,
	unsigned int idx, u32 timestamp,
	unsigned int *frame_len_ptr)
	{
	struct net_device *dev = offload->dev;
	struct net_device_stats *stats = &dev->stats;
	struct sk_buff *skb;
	unsigned int len;
	int err;

	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
	if (!skb)
	return 0;

	err = can_rx_offload_queue_timestamp(offload, skb, timestamp);
	if (err) {
	stats->rx_errors++;
	stats->tx_fifo_errors++;
	}

	return len;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb_queue_timestamp);

	int can_rx_offload_queue_tail(struct can_rx_offload *offload,
	struct sk_buff *skb)
	{
	if (skb_queue_len(&offload->skb_queue) >
	offload->skb_queue_len_max) {
	dev_kfree_skb_any(skb);
	return -ENOBUFS;
	}

	__skb_queue_tail(&offload->skb_irq_queue, skb);

	return 0;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);

	unsigned int
	can_rx_offload_get_echo_skb_queue_tail(struct can_rx_offload *offload,
	unsigned int idx,
	unsigned int *frame_len_ptr)
	{
	struct net_device *dev = offload->dev;
	struct net_device_stats *stats = &dev->stats;
	struct sk_buff *skb;
	unsigned int len;
	int err;

	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
	if (!skb)
	return 0;

	err = can_rx_offload_queue_tail(offload, skb);
	if (err) {
	stats->rx_errors++;
	stats->tx_fifo_errors++;
	}

	return len;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb_queue_tail);

	void can_rx_offload_irq_finish(struct can_rx_offload *offload)
	{
	unsigned long flags;
	int queue_len;

	if (skb_queue_empty_lockless(&offload->skb_irq_queue))
	return;

	spin_lock_irqsave(&offload->skb_queue.lock, flags);
	skb_queue_splice_tail_init(&offload->skb_irq_queue, &offload->skb_queue);
	spin_unlock_irqrestore(&offload->skb_queue.lock, flags);

	queue_len = skb_queue_len(&offload->skb_queue);
	if (queue_len > offload->skb_queue_len_max / 8)
	netdev_dbg(offload->dev, "%s: queue_len=%d\n",
	__func__, queue_len);

	napi_schedule(&offload->napi);
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_irq_finish);

	void can_rx_offload_threaded_irq_finish(struct can_rx_offload *offload)
	{
	unsigned long flags;
	int queue_len;

	if (skb_queue_empty_lockless(&offload->skb_irq_queue))
	return;

	spin_lock_irqsave(&offload->skb_queue.lock, flags);
	skb_queue_splice_tail_init(&offload->skb_irq_queue, &offload->skb_queue);
	spin_unlock_irqrestore(&offload->skb_queue.lock, flags);

	queue_len = skb_queue_len(&offload->skb_queue);
	if (queue_len > offload->skb_queue_len_max / 8)
	netdev_dbg(offload->dev, "%s: queue_len=%d\n",
	__func__, queue_len);

	local_bh_disable();
	napi_schedule(&offload->napi);
	local_bh_enable();
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_threaded_irq_finish);

	static int can_rx_offload_init_queue(struct net_device *dev,
	struct can_rx_offload *offload,
	unsigned int weight)
	{
	offload->dev = dev;

	/* Limit queue len to 4x the weight (rounded to next power of two) */
	offload->skb_queue_len_max = 2 << fls(weight);
	offload->skb_queue_len_max *= 4;
	skb_queue_head_init(&offload->skb_queue);
	__skb_queue_head_init(&offload->skb_irq_queue);

	netif_napi_add_weight(dev, &offload->napi, can_rx_offload_napi_poll,
	weight);

	dev_dbg(dev->dev.parent, "%s: skb_queue_len_max=%d\n",
	__func__, offload->skb_queue_len_max);

	return 0;
	}

	int can_rx_offload_add_timestamp(struct net_device *dev,
	struct can_rx_offload *offload)
	{
	unsigned int weight;

	if (offload->mb_first > BITS_PER_LONG_LONG \|\|
	offload->mb_last > BITS_PER_LONG_LONG \|\| !offload->mailbox_read)
	return -EINVAL;

	if (offload->mb_first < offload->mb_last) {
	offload->inc = true;
	weight = offload->mb_last - offload->mb_first;
	} else {
	offload->inc = false;
	weight = offload->mb_first - offload->mb_last;
	}

	return can_rx_offload_init_queue(dev, offload, weight);
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp);

	int can_rx_offload_add_fifo(struct net_device *dev,
	struct can_rx_offload *offload, unsigned int weight)
	{
	if (!offload->mailbox_read)
	return -EINVAL;

	return can_rx_offload_init_queue(dev, offload, weight);
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo);

	int can_rx_offload_add_manual(struct net_device *dev,
	struct can_rx_offload *offload,
	unsigned int weight)
	{
	if (offload->mailbox_read)
	return -EINVAL;

	return can_rx_offload_init_queue(dev, offload, weight);
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_add_manual);

	void can_rx_offload_enable(struct can_rx_offload *offload)
	{
	napi_enable(&offload->napi);
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_enable);

	void can_rx_offload_del(struct can_rx_offload *offload)
	{
	netif_napi_del(&offload->napi);
	skb_queue_purge(&offload->skb_queue);
	__skb_queue_purge(&offload->skb_irq_queue);
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_del);