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

 /*
  * Copyright (c) 2014 David Jander, Protonic Holland
  * Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
  *
  * 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/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++;
 		stats->rx_packets++;
 		stats->rx_bytes += cf->can_dlc;
 		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);
 	}

 	can_led_event(offload->dev, CAN_LED_EVENT_RX);

 	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);

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

 static struct sk_buff *can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
 {
 	struct sk_buff *skb = NULL;
 	struct can_rx_offload_cb *cb;
 	struct can_frame *cf;
 	int ret;

 	/* If queue is full or skb not available, read to discard mailbox */
 	if (likely(skb_queue_len(&offload->skb_queue) <=
 		   offload->skb_queue_len_max))
 		skb = alloc_can_skb(offload->dev, &cf);

 	if (!skb) {
 		struct can_frame cf_overflow;
 		u32 timestamp;

 		ret = offload->mailbox_read(offload, &cf_overflow,
 					    &timestamp, n);
 		if (ret)
 			offload->dev->stats.rx_dropped++;

 		return NULL;
 	}

 	cb = can_rx_offload_get_cb(skb);
 	ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
 	if (!ret) {
 		kfree_skb(skb);
 		return NULL;
 	}

 	return skb;
 }

 int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending)
 {
 	struct sk_buff_head skb_queue;
 	unsigned int i;

 	__skb_queue_head_init(&skb_queue);

 	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 (!skb)
 			break;

 		__skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
 	}

 	if (!skb_queue_empty(&skb_queue)) {
 		unsigned long flags;
 		u32 queue_len;

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

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

 		can_rx_offload_schedule(offload);
 	}

 	return skb_queue_len(&skb_queue);
 }
 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 ((skb = can_rx_offload_offload_one(offload, 0))) {
 		skb_queue_tail(&offload->skb_queue, skb);
 		received++;
 	}

 	if (received)
 		can_rx_offload_schedule(offload);

 	return received;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);

 int can_rx_offload_irq_queue_err_skb(struct can_rx_offload *offload, struct sk_buff *skb)
 {
 	if (skb_queue_len(&offload->skb_queue) >
 	    offload->skb_queue_len_max)
 		return -ENOMEM;

 	skb_queue_tail(&offload->skb_queue, skb);
 	can_rx_offload_schedule(offload);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_irq_queue_err_skb);

 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 (rounted 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);

 	can_rx_offload_reset(offload);
 	netif_napi_add(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);

 void can_rx_offload_enable(struct can_rx_offload *offload)
 {
 	can_rx_offload_reset(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);
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_del);

 void can_rx_offload_reset(struct can_rx_offload *offload)
 {
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_reset);
	/*
	* Copyright (c) 2014 David Jander, Protonic Holland
	* Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
	*
	* 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/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++;
	stats->rx_packets++;
	stats->rx_bytes += cf->can_dlc;
	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);
	}

	can_led_event(offload->dev, CAN_LED_EVENT_RX);

	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);

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

	static struct sk_buff can_rx_offload_offload_one(struct can_rx_offload offload, unsigned int n)
	{
	struct sk_buff *skb = NULL;
	struct can_rx_offload_cb *cb;
	struct can_frame *cf;
	int ret;

	/* If queue is full or skb not available, read to discard mailbox */
	if (likely(skb_queue_len(&offload->skb_queue) <=
	offload->skb_queue_len_max))
	skb = alloc_can_skb(offload->dev, &cf);

	if (!skb) {
	struct can_frame cf_overflow;
	u32 timestamp;

	ret = offload->mailbox_read(offload, &cf_overflow,
	&timestamp, n);
	if (ret)
	offload->dev->stats.rx_dropped++;

	return NULL;
	}

	cb = can_rx_offload_get_cb(skb);
	ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
	if (!ret) {
	kfree_skb(skb);
	return NULL;
	}

	return skb;
	}

	int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending)
	{
	struct sk_buff_head skb_queue;
	unsigned int i;

	__skb_queue_head_init(&skb_queue);

	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 (!skb)
	break;

	__skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
	}

	if (!skb_queue_empty(&skb_queue)) {
	unsigned long flags;
	u32 queue_len;

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

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

	can_rx_offload_schedule(offload);
	}

	return skb_queue_len(&skb_queue);
	}
	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 ((skb = can_rx_offload_offload_one(offload, 0))) {
	skb_queue_tail(&offload->skb_queue, skb);
	received++;
	}

	if (received)
	can_rx_offload_schedule(offload);

	return received;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);

	int can_rx_offload_irq_queue_err_skb(struct can_rx_offload offload, struct sk_buff skb)
	{
	if (skb_queue_len(&offload->skb_queue) >
	offload->skb_queue_len_max)
	return -ENOMEM;

	skb_queue_tail(&offload->skb_queue, skb);
	can_rx_offload_schedule(offload);

	return 0;
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_irq_queue_err_skb);

	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 (rounted 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);

	can_rx_offload_reset(offload);
	netif_napi_add(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);

	void can_rx_offload_enable(struct can_rx_offload *offload)
	{
	can_rx_offload_reset(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);
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_del);

	void can_rx_offload_reset(struct can_rx_offload *offload)
	{
	}
	EXPORT_SYMBOL_GPL(can_rx_offload_reset);