[linux.git] / drivers / net / can / rx-offload.c

/*
 * Copyright (c) 2014 David Jander, Protonic Holland
 * Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <[email protected]>
 *
 * 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_queue_sorted(struct can_rx_offload *offload,
				struct sk_buff *skb, u32 timestamp)
{
	struct can_rx_offload_cb *cb;
	unsigned long flags;

	if (skb_queue_len(&offload->skb_queue) >
	    offload->skb_queue_len_max)
		return -ENOMEM;

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

	spin_lock_irqsave(&offload->skb_queue.lock, flags);
	__skb_queue_add_sort(&offload->skb_queue, skb, can_rx_offload_compare);
	spin_unlock_irqrestore(&offload->skb_queue.lock, flags);

	can_rx_offload_schedule(offload);

	return 0;
}
EXPORT_SYMBOL_GPL(can_rx_offload_queue_sorted);

unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
					 unsigned int idx, u32 timestamp)
{
	struct net_device *dev = offload->dev;
	struct net_device_stats *stats = &dev->stats;
	struct sk_buff *skb;
	u8 len;
	int err;

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

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

	return len;
}
EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb);

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)
		return -ENOMEM;

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

	return 0;
}
EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);

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);
Commit	Line	Data
d254586c DJ	1	/*
	2	* Copyright (c) 2014 David Jander, Protonic Holland
	3	* Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <[email protected]>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the version 2 of the GNU General Public License
	7	* as published by the Free Software Foundation
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	16	*/
	17
	18	#include <linux/can/dev.h>
	19	#include <linux/can/rx-offload.h>
	20
3abbac0b MKB	21	struct can_rx_offload_cb {
	22	u32 timestamp;
	23	};
	24
	25	static inline struct can_rx_offload_cb can_rx_offload_get_cb(struct sk_buff skb)
	26	{
	27	BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb));
	28
	29	return (struct can_rx_offload_cb *)skb->cb;
	30	}
	31
	32	static inline bool can_rx_offload_le(struct can_rx_offload *offload, unsigned int a, unsigned int b)
	33	{
	34	if (offload->inc)
	35	return a <= b;
	36	else
	37	return a >= b;
	38	}
	39
	40	static inline unsigned int can_rx_offload_inc(struct can_rx_offload offload, unsigned int val)
	41	{
	42	if (offload->inc)
	43	return (*val)++;
	44	else
	45	return (*val)--;
	46	}
	47
d254586c DJ	48	static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
	49	{
	50	struct can_rx_offload *offload = container_of(napi, struct can_rx_offload, napi);
	51	struct net_device *dev = offload->dev;
	52	struct net_device_stats *stats = &dev->stats;
	53	struct sk_buff *skb;
	54	int work_done = 0;
	55
	56	while ((work_done < quota) &&
	57	(skb = skb_dequeue(&offload->skb_queue))) {
	58	struct can_frame cf = (struct can_frame )skb->data;
	59
	60	work_done++;
	61	stats->rx_packets++;
	62	stats->rx_bytes += cf->can_dlc;
	63	netif_receive_skb(skb);
	64	}
	65
	66	if (work_done < quota) {
	67	napi_complete_done(napi, work_done);
	68
	69	/* Check if there was another interrupt */
	70	if (!skb_queue_empty(&offload->skb_queue))
	71	napi_reschedule(&offload->napi);
	72	}
	73
	74	can_led_event(offload->dev, CAN_LED_EVENT_RX);
	75
	76	return work_done;
	77	}
	78
3abbac0b MKB	79	static inline void __skb_queue_add_sort(struct sk_buff_head head, struct sk_buff new,
	80	int (compare)(struct sk_buff a, struct sk_buff *b))
	81	{
6effee68	82	struct sk_buff pos, insert = NULL;
3abbac0b MKB	83
	84	skb_queue_reverse_walk(head, pos) {
	85	const struct can_rx_offload_cb cb_pos, cb_new;
	86
	87	cb_pos = can_rx_offload_get_cb(pos);
	88	cb_new = can_rx_offload_get_cb(new);
	89
	90	netdev_dbg(new->dev,
	91	"%s: pos=0x%08x, new=0x%08x, diff=%10d, queue_len=%d\n",
	92	__func__,
	93	cb_pos->timestamp, cb_new->timestamp,
	94	cb_new->timestamp - cb_pos->timestamp,
	95	skb_queue_len(head));
	96
	97	if (compare(pos, new) < 0)
	98	continue;
	99	insert = pos;
	100	break;
	101	}
6effee68 DM	102	if (!insert)
	103	__skb_queue_head(head, new);
	104	else
	105	__skb_queue_after(head, insert, new);
3abbac0b MKB	106	}
	107
	108	static int can_rx_offload_compare(struct sk_buff a, struct sk_buff b)
	109	{
	110	const struct can_rx_offload_cb cb_a, cb_b;
	111
	112	cb_a = can_rx_offload_get_cb(a);
	113	cb_b = can_rx_offload_get_cb(b);
	114
	115	/* Substract two u32 and return result as int, to keep
	116	* difference steady around the u32 overflow.
	117	*/
	118	return cb_b->timestamp - cb_a->timestamp;
	119	}
	120
d254586c DJ	121	static struct sk_buff can_rx_offload_offload_one(struct can_rx_offload offload, unsigned int n)
	122	{
	123	struct sk_buff *skb = NULL;
3abbac0b	124	struct can_rx_offload_cb *cb;
d254586c DJ	125	struct can_frame *cf;
	126	int ret;
	127
	128	/* If queue is full or skb not available, read to discard mailbox */
	129	if (likely(skb_queue_len(&offload->skb_queue) <=
	130	offload->skb_queue_len_max))
	131	skb = alloc_can_skb(offload->dev, &cf);
	132
	133	if (!skb) {
	134	struct can_frame cf_overflow;
3abbac0b	135	u32 timestamp;
d254586c	136
3abbac0b MKB	137	ret = offload->mailbox_read(offload, &cf_overflow,
3abbac0b MKB	138	&timestamp, n);
d254586c DJ	139	if (ret)
	140	offload->dev->stats.rx_dropped++;
	141
	142	return NULL;
	143	}
	144
3abbac0b MKB	145	cb = can_rx_offload_get_cb(skb);
3abbac0b MKB	146	ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
d254586c DJ	147	if (!ret) {
	148	kfree_skb(skb);
	149	return NULL;
	150	}
	151
	152	return skb;
	153	}
	154
3abbac0b MKB	155	int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending)
	156	{
	157	struct sk_buff_head skb_queue;
	158	unsigned int i;
	159
	160	__skb_queue_head_init(&skb_queue);
	161
	162	for (i = offload->mb_first;
	163	can_rx_offload_le(offload, i, offload->mb_last);
	164	can_rx_offload_inc(offload, &i)) {
	165	struct sk_buff *skb;
	166
	167	if (!(pending & BIT_ULL(i)))
	168	continue;
	169
	170	skb = can_rx_offload_offload_one(offload, i);
	171	if (!skb)
	172	break;
	173
	174	__skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
	175	}
	176
	177	if (!skb_queue_empty(&skb_queue)) {
	178	unsigned long flags;
	179	u32 queue_len;
	180
	181	spin_lock_irqsave(&offload->skb_queue.lock, flags);
	182	skb_queue_splice_tail(&skb_queue, &offload->skb_queue);
	183	spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
	184
	185	if ((queue_len = skb_queue_len(&offload->skb_queue)) >
	186	(offload->skb_queue_len_max / 8))
	187	netdev_dbg(offload->dev, "%s: queue_len=%d\n",
	188	__func__, queue_len);
	189
	190	can_rx_offload_schedule(offload);
	191	}
	192
	193	return skb_queue_len(&skb_queue);
	194	}
	195	EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_timestamp);
	196
d254586c DJ	197	int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload)
	198	{
	199	struct sk_buff *skb;
	200	int received = 0;
	201
	202	while ((skb = can_rx_offload_offload_one(offload, 0))) {
	203	skb_queue_tail(&offload->skb_queue, skb);
	204	received++;
	205	}
	206
	207	if (received)
	208	can_rx_offload_schedule(offload);
	209
	210	return received;
	211	}
	212	EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);
	213
55059f2b OR	214	int can_rx_offload_queue_sorted(struct can_rx_offload *offload,
	215	struct sk_buff *skb, u32 timestamp)
	216	{
	217	struct can_rx_offload_cb *cb;
	218	unsigned long flags;
	219
	220	if (skb_queue_len(&offload->skb_queue) >
	221	offload->skb_queue_len_max)
	222	return -ENOMEM;
	223
	224	cb = can_rx_offload_get_cb(skb);
	225	cb->timestamp = timestamp;
	226
	227	spin_lock_irqsave(&offload->skb_queue.lock, flags);
	228	__skb_queue_add_sort(&offload->skb_queue, skb, can_rx_offload_compare);
	229	spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
	230
	231	can_rx_offload_schedule(offload);
	232
	233	return 0;
	234	}
	235	EXPORT_SYMBOL_GPL(can_rx_offload_queue_sorted);
	236
	237	unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
	238	unsigned int idx, u32 timestamp)
	239	{
	240	struct net_device *dev = offload->dev;
	241	struct net_device_stats *stats = &dev->stats;
	242	struct sk_buff *skb;
	243	u8 len;
	244	int err;
	245
	246	skb = __can_get_echo_skb(dev, idx, &len);
	247	if (!skb)
	248	return 0;
	249
	250	err = can_rx_offload_queue_sorted(offload, skb, timestamp);
	251	if (err) {
	252	stats->rx_errors++;
	253	stats->tx_fifo_errors++;
	254	}
	255
	256	return len;
	257	}
	258	EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb);
	259
4530ec36 OR	260	int can_rx_offload_queue_tail(struct can_rx_offload *offload,
4530ec36 OR	261	struct sk_buff *skb)
d254586c DJ	262	{
	263	if (skb_queue_len(&offload->skb_queue) >
	264	offload->skb_queue_len_max)
	265	return -ENOMEM;
	266
	267	skb_queue_tail(&offload->skb_queue, skb);
	268	can_rx_offload_schedule(offload);
	269
	270	return 0;
	271	}
4530ec36	272	EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);
d254586c DJ	273
	274	static int can_rx_offload_init_queue(struct net_device dev, struct can_rx_offload offload, unsigned int weight)
	275	{
	276	offload->dev = dev;
	277
	278	/* Limit queue len to 4x the weight (rounted to next power of two) */
	279	offload->skb_queue_len_max = 2 << fls(weight);
	280	offload->skb_queue_len_max *= 4;
	281	skb_queue_head_init(&offload->skb_queue);
	282
	283	can_rx_offload_reset(offload);
	284	netif_napi_add(dev, &offload->napi, can_rx_offload_napi_poll, weight);
	285
	286	dev_dbg(dev->dev.parent, "%s: skb_queue_len_max=%d\n",
	287	__func__, offload->skb_queue_len_max);
	288
	289	return 0;
	290	}
	291
3abbac0b MKB	292	int can_rx_offload_add_timestamp(struct net_device dev, struct can_rx_offload offload)
	293	{
	294	unsigned int weight;
	295
	296	if (offload->mb_first > BITS_PER_LONG_LONG \|\|
	297	offload->mb_last > BITS_PER_LONG_LONG \|\| !offload->mailbox_read)
	298	return -EINVAL;
	299
	300	if (offload->mb_first < offload->mb_last) {
	301	offload->inc = true;
	302	weight = offload->mb_last - offload->mb_first;
	303	} else {
	304	offload->inc = false;
	305	weight = offload->mb_first - offload->mb_last;
	306	}
	307
41e0a3fd	308	return can_rx_offload_init_queue(dev, offload, weight);
3abbac0b MKB	309	}
	310	EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp);
	311
d254586c DJ	312	int can_rx_offload_add_fifo(struct net_device dev, struct can_rx_offload offload, unsigned int weight)
	313	{
	314	if (!offload->mailbox_read)
	315	return -EINVAL;
	316
	317	return can_rx_offload_init_queue(dev, offload, weight);
	318	}
	319	EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo);
	320
	321	void can_rx_offload_enable(struct can_rx_offload *offload)
	322	{
	323	can_rx_offload_reset(offload);
	324	napi_enable(&offload->napi);
	325	}
	326	EXPORT_SYMBOL_GPL(can_rx_offload_enable);
	327
	328	void can_rx_offload_del(struct can_rx_offload *offload)
	329	{
	330	netif_napi_del(&offload->napi);
	331	skb_queue_purge(&offload->skb_queue);
	332	}
	333	EXPORT_SYMBOL_GPL(can_rx_offload_del);
	334
	335	void can_rx_offload_reset(struct can_rx_offload *offload)
	336	{
	337	}
	338	EXPORT_SYMBOL_GPL(can_rx_offload_reset);