2 * Copyright (c) 2014 David Jander, Protonic Holland
3 * Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
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
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.
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/>.
18 #include <linux/can/dev.h>
19 #include <linux/can/rx-offload.h>
21 struct can_rx_offload_cb {
25 static inline struct can_rx_offload_cb *can_rx_offload_get_cb(struct sk_buff *skb)
27 BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb));
29 return (struct can_rx_offload_cb *)skb->cb;
32 static inline bool can_rx_offload_le(struct can_rx_offload *offload, unsigned int a, unsigned int b)
40 static inline unsigned int can_rx_offload_inc(struct can_rx_offload *offload, unsigned int *val)
48 static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
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;
56 while ((work_done < quota) &&
57 (skb = skb_dequeue(&offload->skb_queue))) {
58 struct can_frame *cf = (struct can_frame *)skb->data;
62 stats->rx_bytes += cf->can_dlc;
63 netif_receive_skb(skb);
66 if (work_done < quota) {
67 napi_complete_done(napi, work_done);
69 /* Check if there was another interrupt */
70 if (!skb_queue_empty(&offload->skb_queue))
71 napi_reschedule(&offload->napi);
74 can_led_event(offload->dev, CAN_LED_EVENT_RX);
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))
82 struct sk_buff *pos, *insert = (struct sk_buff *)head;
84 skb_queue_reverse_walk(head, pos) {
85 const struct can_rx_offload_cb *cb_pos, *cb_new;
87 cb_pos = can_rx_offload_get_cb(pos);
88 cb_new = can_rx_offload_get_cb(new);
91 "%s: pos=0x%08x, new=0x%08x, diff=%10d, queue_len=%d\n",
93 cb_pos->timestamp, cb_new->timestamp,
94 cb_new->timestamp - cb_pos->timestamp,
97 if (compare(pos, new) < 0)
103 __skb_queue_after(head, insert, new);
106 static int can_rx_offload_compare(struct sk_buff *a, struct sk_buff *b)
108 const struct can_rx_offload_cb *cb_a, *cb_b;
110 cb_a = can_rx_offload_get_cb(a);
111 cb_b = can_rx_offload_get_cb(b);
113 /* Substract two u32 and return result as int, to keep
114 * difference steady around the u32 overflow.
116 return cb_b->timestamp - cb_a->timestamp;
120 * can_rx_offload_offload_one() - Read one CAN frame from HW
121 * @offload: pointer to rx_offload context
122 * @n: number of mailbox to read
124 * The task of this function is to read a CAN frame from mailbox @n
125 * from the device and return the mailbox's content as a struct
128 * If the struct can_rx_offload::skb_queue exceeds the maximal queue
129 * length (struct can_rx_offload::skb_queue_len_max) or no skb can be
130 * allocated, the mailbox contents is discarded by reading it into an
131 * overflow buffer. This way the mailbox is marked as free by the
134 * Return: A pointer to skb containing the CAN frame on success.
136 * NULL if the mailbox @n is empty.
138 * ERR_PTR() in case of an error
140 static struct sk_buff *
141 can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
143 struct sk_buff *skb = NULL, *skb_error = NULL;
144 struct can_rx_offload_cb *cb;
145 struct can_frame *cf;
148 if (likely(skb_queue_len(&offload->skb_queue) <
149 offload->skb_queue_len_max)) {
150 skb = alloc_can_skb(offload->dev, &cf);
152 skb_error = ERR_PTR(-ENOMEM); /* skb alloc failed */
154 skb_error = ERR_PTR(-ENOBUFS); /* skb_queue is full */
157 /* If queue is full or skb not available, drop by reading into
160 if (unlikely(skb_error)) {
161 struct can_frame cf_overflow;
164 ret = offload->mailbox_read(offload, &cf_overflow,
167 /* Mailbox was empty. */
171 /* Mailbox has been read and we're dropping it or
172 * there was a problem reading the mailbox.
174 * Increment error counters in any case.
176 offload->dev->stats.rx_dropped++;
177 offload->dev->stats.rx_fifo_errors++;
179 /* There was a problem reading the mailbox, propagate
182 if (unlikely(ret < 0))
188 cb = can_rx_offload_get_cb(skb);
189 ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
191 /* Mailbox was empty. */
192 if (unlikely(!ret)) {
197 /* There was a problem reading the mailbox, propagate error value. */
198 if (unlikely(ret < 0)) {
201 offload->dev->stats.rx_dropped++;
202 offload->dev->stats.rx_fifo_errors++;
207 /* Mailbox was read. */
211 int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending)
213 struct sk_buff_head skb_queue;
216 __skb_queue_head_init(&skb_queue);
218 for (i = offload->mb_first;
219 can_rx_offload_le(offload, i, offload->mb_last);
220 can_rx_offload_inc(offload, &i)) {
223 if (!(pending & BIT_ULL(i)))
226 skb = can_rx_offload_offload_one(offload, i);
227 if (IS_ERR_OR_NULL(skb))
230 __skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
233 if (!skb_queue_empty(&skb_queue)) {
237 spin_lock_irqsave(&offload->skb_queue.lock, flags);
238 skb_queue_splice_tail(&skb_queue, &offload->skb_queue);
239 spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
241 if ((queue_len = skb_queue_len(&offload->skb_queue)) >
242 (offload->skb_queue_len_max / 8))
243 netdev_dbg(offload->dev, "%s: queue_len=%d\n",
244 __func__, queue_len);
246 can_rx_offload_schedule(offload);
249 return skb_queue_len(&skb_queue);
251 EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_timestamp);
253 int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload)
259 skb = can_rx_offload_offload_one(offload, 0);
265 skb_queue_tail(&offload->skb_queue, skb);
270 can_rx_offload_schedule(offload);
274 EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);
276 int can_rx_offload_queue_sorted(struct can_rx_offload *offload,
277 struct sk_buff *skb, u32 timestamp)
279 struct can_rx_offload_cb *cb;
282 if (skb_queue_len(&offload->skb_queue) >
283 offload->skb_queue_len_max) {
284 dev_kfree_skb_any(skb);
288 cb = can_rx_offload_get_cb(skb);
289 cb->timestamp = timestamp;
291 spin_lock_irqsave(&offload->skb_queue.lock, flags);
292 __skb_queue_add_sort(&offload->skb_queue, skb, can_rx_offload_compare);
293 spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
295 can_rx_offload_schedule(offload);
299 EXPORT_SYMBOL_GPL(can_rx_offload_queue_sorted);
301 unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
302 unsigned int idx, u32 timestamp)
304 struct net_device *dev = offload->dev;
305 struct net_device_stats *stats = &dev->stats;
310 skb = __can_get_echo_skb(dev, idx, &len);
314 err = can_rx_offload_queue_sorted(offload, skb, timestamp);
317 stats->tx_fifo_errors++;
322 EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb);
324 int can_rx_offload_queue_tail(struct can_rx_offload *offload,
327 if (skb_queue_len(&offload->skb_queue) >
328 offload->skb_queue_len_max) {
329 dev_kfree_skb_any(skb);
333 skb_queue_tail(&offload->skb_queue, skb);
334 can_rx_offload_schedule(offload);
338 EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);
340 static int can_rx_offload_init_queue(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
344 /* Limit queue len to 4x the weight (rounted to next power of two) */
345 offload->skb_queue_len_max = 2 << fls(weight);
346 offload->skb_queue_len_max *= 4;
347 skb_queue_head_init(&offload->skb_queue);
349 can_rx_offload_reset(offload);
350 netif_napi_add(dev, &offload->napi, can_rx_offload_napi_poll, weight);
352 dev_dbg(dev->dev.parent, "%s: skb_queue_len_max=%d\n",
353 __func__, offload->skb_queue_len_max);
358 int can_rx_offload_add_timestamp(struct net_device *dev, struct can_rx_offload *offload)
362 if (offload->mb_first > BITS_PER_LONG_LONG ||
363 offload->mb_last > BITS_PER_LONG_LONG || !offload->mailbox_read)
366 if (offload->mb_first < offload->mb_last) {
368 weight = offload->mb_last - offload->mb_first;
370 offload->inc = false;
371 weight = offload->mb_first - offload->mb_last;
374 return can_rx_offload_init_queue(dev, offload, weight);;
376 EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp);
378 int can_rx_offload_add_fifo(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
380 if (!offload->mailbox_read)
383 return can_rx_offload_init_queue(dev, offload, weight);
385 EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo);
387 void can_rx_offload_enable(struct can_rx_offload *offload)
389 can_rx_offload_reset(offload);
390 napi_enable(&offload->napi);
392 EXPORT_SYMBOL_GPL(can_rx_offload_enable);
394 void can_rx_offload_del(struct can_rx_offload *offload)
396 netif_napi_del(&offload->napi);
397 skb_queue_purge(&offload->skb_queue);
399 EXPORT_SYMBOL_GPL(can_rx_offload_del);
401 void can_rx_offload_reset(struct can_rx_offload *offload)
404 EXPORT_SYMBOL_GPL(can_rx_offload_reset);