summaryrefslogtreecommitdiff
path: root/drivers/net/can/rx-offload.c
blob: d94dae21682093112ce2037d5672f0a5779d470e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
/*
 * 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 = (struct sk_buff *)head;

	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;
	}

	__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);