1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (C) 2007, 2011 Wolfgang Grandegger <wg@grandegger.com>
3 * Copyright (C) 2012 Stephane Grosjean <s.grosjean@peak-system.com>
4 *
5 * Copyright (C) 2016  PEAK System-Technik GmbH
6 */
7
8#include <linux/can.h>
9#include <linux/can/dev.h>
10
11#include "peak_canfd_user.h"
12
13/* internal IP core cache size (used as default echo skbs max number) */
14#define PCANFD_ECHO_SKB_MAX		24
15
16/* bittiming ranges of the PEAK-System PC CAN-FD interfaces */
17static const struct can_bittiming_const peak_canfd_nominal_const = {
18	.name = "peak_canfd",
19	.tseg1_min = 1,
20	.tseg1_max = (1 << PUCAN_TSLOW_TSGEG1_BITS),
21	.tseg2_min = 1,
22	.tseg2_max = (1 << PUCAN_TSLOW_TSGEG2_BITS),
23	.sjw_max = (1 << PUCAN_TSLOW_SJW_BITS),
24	.brp_min = 1,
25	.brp_max = (1 << PUCAN_TSLOW_BRP_BITS),
26	.brp_inc = 1,
27};
28
29static const struct can_bittiming_const peak_canfd_data_const = {
30	.name = "peak_canfd",
31	.tseg1_min = 1,
32	.tseg1_max = (1 << PUCAN_TFAST_TSGEG1_BITS),
33	.tseg2_min = 1,
34	.tseg2_max = (1 << PUCAN_TFAST_TSGEG2_BITS),
35	.sjw_max = (1 << PUCAN_TFAST_SJW_BITS),
36	.brp_min = 1,
37	.brp_max = (1 << PUCAN_TFAST_BRP_BITS),
38	.brp_inc = 1,
39};
40
41static struct peak_canfd_priv *pucan_init_cmd(struct peak_canfd_priv *priv)
42{
43	priv->cmd_len = 0;
44	return priv;
45}
46
47static void *pucan_add_cmd(struct peak_canfd_priv *priv, int cmd_op)
48{
49	struct pucan_command *cmd;
50
51	if (priv->cmd_len + sizeof(*cmd) > priv->cmd_maxlen)
52		return NULL;
53
54	cmd = priv->cmd_buffer + priv->cmd_len;
55
56	/* reset all unused bit to default */
57	memset(cmd, 0, sizeof(*cmd));
58
59	cmd->opcode_channel = pucan_cmd_opcode_channel(priv->index, cmd_op);
60	priv->cmd_len += sizeof(*cmd);
61
62	return cmd;
63}
64
65static int pucan_write_cmd(struct peak_canfd_priv *priv)
66{
67	int err;
68
69	if (priv->pre_cmd) {
70		err = priv->pre_cmd(priv);
71		if (err)
72			return err;
73	}
74
75	err = priv->write_cmd(priv);
76	if (err)
77		return err;
78
79	if (priv->post_cmd)
80		err = priv->post_cmd(priv);
81
82	return err;
83}
84
85/* uCAN commands interface functions */
86static int pucan_set_reset_mode(struct peak_canfd_priv *priv)
87{
88	pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_RESET_MODE);
89	return pucan_write_cmd(priv);
90}
91
92static int pucan_set_normal_mode(struct peak_canfd_priv *priv)
93{
94	int err;
95
96	pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_NORMAL_MODE);
97	err = pucan_write_cmd(priv);
98	if (!err)
99		priv->can.state = CAN_STATE_ERROR_ACTIVE;
100
101	return err;
102}
103
104static int pucan_set_listen_only_mode(struct peak_canfd_priv *priv)
105{
106	int err;
107
108	pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_LISTEN_ONLY_MODE);
109	err = pucan_write_cmd(priv);
110	if (!err)
111		priv->can.state = CAN_STATE_ERROR_ACTIVE;
112
113	return err;
114}
115
116static int pucan_set_timing_slow(struct peak_canfd_priv *priv,
117				 const struct can_bittiming *pbt)
118{
119	struct pucan_timing_slow *cmd;
120
121	cmd = pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_TIMING_SLOW);
122
123	cmd->sjw_t = PUCAN_TSLOW_SJW_T(pbt->sjw - 1,
124				       priv->can.ctrlmode &
125				       CAN_CTRLMODE_3_SAMPLES);
126	cmd->tseg1 = PUCAN_TSLOW_TSEG1(pbt->prop_seg + pbt->phase_seg1 - 1);
127	cmd->tseg2 = PUCAN_TSLOW_TSEG2(pbt->phase_seg2 - 1);
128	cmd->brp = cpu_to_le16(PUCAN_TSLOW_BRP(pbt->brp - 1));
129
130	cmd->ewl = 96;	/* default */
131
132	netdev_dbg(priv->ndev,
133		   "nominal: brp=%u tseg1=%u tseg2=%u sjw=%u\n",
134		   le16_to_cpu(cmd->brp), cmd->tseg1, cmd->tseg2, cmd->sjw_t);
135
136	return pucan_write_cmd(priv);
137}
138
139static int pucan_set_timing_fast(struct peak_canfd_priv *priv,
140				 const struct can_bittiming *pbt)
141{
142	struct pucan_timing_fast *cmd;
143
144	cmd = pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_TIMING_FAST);
145
146	cmd->sjw = PUCAN_TFAST_SJW(pbt->sjw - 1);
147	cmd->tseg1 = PUCAN_TFAST_TSEG1(pbt->prop_seg + pbt->phase_seg1 - 1);
148	cmd->tseg2 = PUCAN_TFAST_TSEG2(pbt->phase_seg2 - 1);
149	cmd->brp = cpu_to_le16(PUCAN_TFAST_BRP(pbt->brp - 1));
150
151	netdev_dbg(priv->ndev,
152		   "data: brp=%u tseg1=%u tseg2=%u sjw=%u\n",
153		   le16_to_cpu(cmd->brp), cmd->tseg1, cmd->tseg2, cmd->sjw);
154
155	return pucan_write_cmd(priv);
156}
157
158static int pucan_set_std_filter(struct peak_canfd_priv *priv, u8 row, u32 mask)
159{
160	struct pucan_std_filter *cmd;
161
162	cmd = pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_SET_STD_FILTER);
163
164	/* all the 11-bits CAN ID values are represented by one bit in a
165	 * 64 rows array of 32 bits: the upper 6 bits of the CAN ID select the
166	 * row while the lowest 5 bits select the bit in that row.
167	 *
168	 * bit	filter
169	 * 1	passed
170	 * 0	discarded
171	 */
172
173	/* select the row */
174	cmd->idx = row;
175
176	/* set/unset bits in the row */
177	cmd->mask = cpu_to_le32(mask);
178
179	return pucan_write_cmd(priv);
180}
181
182static int pucan_tx_abort(struct peak_canfd_priv *priv, u16 flags)
183{
184	struct pucan_tx_abort *cmd;
185
186	cmd = pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_TX_ABORT);
187
188	cmd->flags = cpu_to_le16(flags);
189
190	return pucan_write_cmd(priv);
191}
192
193static int pucan_clr_err_counters(struct peak_canfd_priv *priv)
194{
195	struct pucan_wr_err_cnt *cmd;
196
197	cmd = pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_WR_ERR_CNT);
198
199	cmd->sel_mask = cpu_to_le16(PUCAN_WRERRCNT_TE | PUCAN_WRERRCNT_RE);
200	cmd->tx_counter = 0;
201	cmd->rx_counter = 0;
202
203	return pucan_write_cmd(priv);
204}
205
206static int pucan_set_options(struct peak_canfd_priv *priv, u16 opt_mask)
207{
208	struct pucan_options *cmd;
209
210	cmd = pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_SET_EN_OPTION);
211
212	cmd->options = cpu_to_le16(opt_mask);
213
214	return pucan_write_cmd(priv);
215}
216
217static int pucan_clr_options(struct peak_canfd_priv *priv, u16 opt_mask)
218{
219	struct pucan_options *cmd;
220
221	cmd = pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_CLR_DIS_OPTION);
222
223	cmd->options = cpu_to_le16(opt_mask);
224
225	return pucan_write_cmd(priv);
226}
227
228static int pucan_setup_rx_barrier(struct peak_canfd_priv *priv)
229{
230	pucan_add_cmd(pucan_init_cmd(priv), PUCAN_CMD_RX_BARRIER);
231
232	return pucan_write_cmd(priv);
233}
234
235static int pucan_netif_rx(struct sk_buff *skb, __le32 ts_low, __le32 ts_high)
236{
237	struct skb_shared_hwtstamps *hwts = skb_hwtstamps(skb);
238	u64 ts_us;
239
240	ts_us = (u64)le32_to_cpu(ts_high) << 32;
241	ts_us |= le32_to_cpu(ts_low);
242
243	/* IP core timestamps are µs. */
244	hwts->hwtstamp = ns_to_ktime(ts_us * NSEC_PER_USEC);
245
246	return netif_rx(skb);
247}
248
249/* handle the reception of one CAN frame */
250static int pucan_handle_can_rx(struct peak_canfd_priv *priv,
251			       struct pucan_rx_msg *msg)
252{
253	struct net_device_stats *stats = &priv->ndev->stats;
254	struct canfd_frame *cf;
255	struct sk_buff *skb;
256	const u16 rx_msg_flags = le16_to_cpu(msg->flags);
257	u8 cf_len;
258
259	if (rx_msg_flags & PUCAN_MSG_EXT_DATA_LEN)
260		cf_len = can_dlc2len(get_canfd_dlc(pucan_msg_get_dlc(msg)));
261	else
262		cf_len = get_can_dlc(pucan_msg_get_dlc(msg));
263
264	/* if this frame is an echo, */
265	if (rx_msg_flags & PUCAN_MSG_LOOPED_BACK) {
266		unsigned long flags;
267
268		spin_lock_irqsave(&priv->echo_lock, flags);
269		can_get_echo_skb(priv->ndev, msg->client);
270
271		/* count bytes of the echo instead of skb */
272		stats->tx_bytes += cf_len;
273		stats->tx_packets++;
274
275		/* restart tx queue (a slot is free) */
276		netif_wake_queue(priv->ndev);
277
278		spin_unlock_irqrestore(&priv->echo_lock, flags);
279
280		/* if this frame is only an echo, stop here. Otherwise,
281		 * continue to push this application self-received frame into
282		 * its own rx queue.
283		 */
284		if (!(rx_msg_flags & PUCAN_MSG_SELF_RECEIVE))
285			return 0;
286	}
287
288	/* otherwise, it should be pushed into rx fifo */
289	if (rx_msg_flags & PUCAN_MSG_EXT_DATA_LEN) {
290		/* CANFD frame case */
291		skb = alloc_canfd_skb(priv->ndev, &cf);
292		if (!skb)
293			return -ENOMEM;
294
295		if (rx_msg_flags & PUCAN_MSG_BITRATE_SWITCH)
296			cf->flags |= CANFD_BRS;
297
298		if (rx_msg_flags & PUCAN_MSG_ERROR_STATE_IND)
299			cf->flags |= CANFD_ESI;
300	} else {
301		/* CAN 2.0 frame case */
302		skb = alloc_can_skb(priv->ndev, (struct can_frame **)&cf);
303		if (!skb)
304			return -ENOMEM;
305	}
306
307	cf->can_id = le32_to_cpu(msg->can_id);
308	cf->len = cf_len;
309
310	if (rx_msg_flags & PUCAN_MSG_EXT_ID)
311		cf->can_id |= CAN_EFF_FLAG;
312
313	if (rx_msg_flags & PUCAN_MSG_RTR)
314		cf->can_id |= CAN_RTR_FLAG;
315	else
316		memcpy(cf->data, msg->d, cf->len);
317
318	stats->rx_bytes += cf->len;
319	stats->rx_packets++;
320
321	pucan_netif_rx(skb, msg->ts_low, msg->ts_high);
322
323	return 0;
324}
325
326/* handle rx/tx error counters notification */
327static int pucan_handle_error(struct peak_canfd_priv *priv,
328			      struct pucan_error_msg *msg)
329{
330	priv->bec.txerr = msg->tx_err_cnt;
331	priv->bec.rxerr = msg->rx_err_cnt;
332
333	return 0;
334}
335
336/* handle status notification */
337static int pucan_handle_status(struct peak_canfd_priv *priv,
338			       struct pucan_status_msg *msg)
339{
340	struct net_device *ndev = priv->ndev;
341	struct net_device_stats *stats = &ndev->stats;
342	struct can_frame *cf;
343	struct sk_buff *skb;
344
345	/* this STATUS is the CNF of the RX_BARRIER: Tx path can be setup */
346	if (pucan_status_is_rx_barrier(msg)) {
347		if (priv->enable_tx_path) {
348			int err = priv->enable_tx_path(priv);
349
350			if (err)
351				return err;
352		}
353
354		/* wake network queue up (echo_skb array is empty) */
355		netif_wake_queue(ndev);
356
357		return 0;
358	}
359
360	skb = alloc_can_err_skb(ndev, &cf);
361
362	/* test state error bits according to their priority */
363	if (pucan_status_is_busoff(msg)) {
364		netdev_dbg(ndev, "Bus-off entry status\n");
365		priv->can.state = CAN_STATE_BUS_OFF;
366		priv->can.can_stats.bus_off++;
367		can_bus_off(ndev);
368		if (skb)
369			cf->can_id |= CAN_ERR_BUSOFF;
370
371	} else if (pucan_status_is_passive(msg)) {
372		netdev_dbg(ndev, "Error passive status\n");
373		priv->can.state = CAN_STATE_ERROR_PASSIVE;
374		priv->can.can_stats.error_passive++;
375		if (skb) {
376			cf->can_id |= CAN_ERR_CRTL;
377			cf->data[1] = (priv->bec.txerr > priv->bec.rxerr) ?
378					CAN_ERR_CRTL_TX_PASSIVE :
379					CAN_ERR_CRTL_RX_PASSIVE;
380			cf->data[6] = priv->bec.txerr;
381			cf->data[7] = priv->bec.rxerr;
382		}
383
384	} else if (pucan_status_is_warning(msg)) {
385		netdev_dbg(ndev, "Error warning status\n");
386		priv->can.state = CAN_STATE_ERROR_WARNING;
387		priv->can.can_stats.error_warning++;
388		if (skb) {
389			cf->can_id |= CAN_ERR_CRTL;
390			cf->data[1] = (priv->bec.txerr > priv->bec.rxerr) ?
391					CAN_ERR_CRTL_TX_WARNING :
392					CAN_ERR_CRTL_RX_WARNING;
393			cf->data[6] = priv->bec.txerr;
394			cf->data[7] = priv->bec.rxerr;
395		}
396
397	} else if (priv->can.state != CAN_STATE_ERROR_ACTIVE) {
398		/* back to ERROR_ACTIVE */
399		netdev_dbg(ndev, "Error active status\n");
400		can_change_state(ndev, cf, CAN_STATE_ERROR_ACTIVE,
401				 CAN_STATE_ERROR_ACTIVE);
402	} else {
403		dev_kfree_skb(skb);
404		return 0;
405	}
406
407	if (!skb) {
408		stats->rx_dropped++;
409		return -ENOMEM;
410	}
411
412	stats->rx_packets++;
413	stats->rx_bytes += cf->can_dlc;
414	pucan_netif_rx(skb, msg->ts_low, msg->ts_high);
415
416	return 0;
417}
418
419/* handle uCAN Rx overflow notification */
420static int pucan_handle_cache_critical(struct peak_canfd_priv *priv)
421{
422	struct net_device_stats *stats = &priv->ndev->stats;
423	struct can_frame *cf;
424	struct sk_buff *skb;
425
426	stats->rx_over_errors++;
427	stats->rx_errors++;
428
429	skb = alloc_can_err_skb(priv->ndev, &cf);
430	if (!skb) {
431		stats->rx_dropped++;
432		return -ENOMEM;
433	}
434
435	cf->can_id |= CAN_ERR_CRTL;
436	cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
437
438	cf->data[6] = priv->bec.txerr;
439	cf->data[7] = priv->bec.rxerr;
440
441	stats->rx_bytes += cf->can_dlc;
442	stats->rx_packets++;
443	netif_rx(skb);
444
445	return 0;
446}
447
448/* handle a single uCAN message */
449int peak_canfd_handle_msg(struct peak_canfd_priv *priv,
450			  struct pucan_rx_msg *msg)
451{
452	u16 msg_type = le16_to_cpu(msg->type);
453	int msg_size = le16_to_cpu(msg->size);
454	int err;
455
456	if (!msg_size || !msg_type) {
457		/* null packet found: end of list */
458		goto exit;
459	}
460
461	switch (msg_type) {
462	case PUCAN_MSG_CAN_RX:
463		err = pucan_handle_can_rx(priv, (struct pucan_rx_msg *)msg);
464		break;
465	case PUCAN_MSG_ERROR:
466		err = pucan_handle_error(priv, (struct pucan_error_msg *)msg);
467		break;
468	case PUCAN_MSG_STATUS:
469		err = pucan_handle_status(priv, (struct pucan_status_msg *)msg);
470		break;
471	case PUCAN_MSG_CACHE_CRITICAL:
472		err = pucan_handle_cache_critical(priv);
473		break;
474	default:
475		err = 0;
476	}
477
478	if (err < 0)
479		return err;
480
481exit:
482	return msg_size;
483}
484
485/* handle a list of rx_count messages from rx_msg memory address */
486int peak_canfd_handle_msgs_list(struct peak_canfd_priv *priv,
487				struct pucan_rx_msg *msg_list, int msg_count)
488{
489	void *msg_ptr = msg_list;
490	int i, msg_size = 0;
491
492	for (i = 0; i < msg_count; i++) {
493		msg_size = peak_canfd_handle_msg(priv, msg_ptr);
494
495		/* a null packet can be found at the end of a list */
496		if (msg_size <= 0)
497			break;
498
499		msg_ptr += ALIGN(msg_size, 4);
500	}
501
502	if (msg_size < 0)
503		return msg_size;
504
505	return i;
506}
507
508static int peak_canfd_start(struct peak_canfd_priv *priv)
509{
510	int err;
511
512	err = pucan_clr_err_counters(priv);
513	if (err)
514		goto err_exit;
515
516	priv->echo_idx = 0;
517
518	priv->bec.txerr = 0;
519	priv->bec.rxerr = 0;
520
521	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
522		err = pucan_set_listen_only_mode(priv);
523	else
524		err = pucan_set_normal_mode(priv);
525
526err_exit:
527	return err;
528}
529
530static void peak_canfd_stop(struct peak_canfd_priv *priv)
531{
532	int err;
533
534	/* go back to RESET mode */
535	err = pucan_set_reset_mode(priv);
536	if (err) {
537		netdev_err(priv->ndev, "channel %u reset failed\n",
538			   priv->index);
539	} else {
540		/* abort last Tx (MUST be done in RESET mode only!) */
541		pucan_tx_abort(priv, PUCAN_TX_ABORT_FLUSH);
542	}
543}
544
545static int peak_canfd_set_mode(struct net_device *ndev, enum can_mode mode)
546{
547	struct peak_canfd_priv *priv = netdev_priv(ndev);
548
549	switch (mode) {
550	case CAN_MODE_START:
551		peak_canfd_start(priv);
552		netif_wake_queue(ndev);
553		break;
554	default:
555		return -EOPNOTSUPP;
556	}
557
558	return 0;
559}
560
561static int peak_canfd_get_berr_counter(const struct net_device *ndev,
562				       struct can_berr_counter *bec)
563{
564	struct peak_canfd_priv *priv = netdev_priv(ndev);
565
566	*bec = priv->bec;
567	return 0;
568}
569
570static int peak_canfd_open(struct net_device *ndev)
571{
572	struct peak_canfd_priv *priv = netdev_priv(ndev);
573	int i, err = 0;
574
575	err = open_candev(ndev);
576	if (err) {
577		netdev_err(ndev, "open_candev() failed, error %d\n", err);
578		goto err_exit;
579	}
580
581	err = pucan_set_reset_mode(priv);
582	if (err)
583		goto err_close;
584
585	if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
586		if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
587			err = pucan_clr_options(priv, PUCAN_OPTION_CANDFDISO);
588		else
589			err = pucan_set_options(priv, PUCAN_OPTION_CANDFDISO);
590
591		if (err)
592			goto err_close;
593	}
594
595	/* set option: get rx/tx error counters */
596	err = pucan_set_options(priv, PUCAN_OPTION_ERROR);
597	if (err)
598		goto err_close;
599
600	/* accept all standard CAN ID */
601	for (i = 0; i <= PUCAN_FLTSTD_ROW_IDX_MAX; i++)
602		pucan_set_std_filter(priv, i, 0xffffffff);
603
604	err = peak_canfd_start(priv);
605	if (err)
606		goto err_close;
607
608	/* receiving the RB status says when Tx path is ready */
609	err = pucan_setup_rx_barrier(priv);
610	if (!err)
611		goto err_exit;
612
613err_close:
614	close_candev(ndev);
615err_exit:
616	return err;
617}
618
619static int peak_canfd_set_bittiming(struct net_device *ndev)
620{
621	struct peak_canfd_priv *priv = netdev_priv(ndev);
622
623	return pucan_set_timing_slow(priv, &priv->can.bittiming);
624}
625
626static int peak_canfd_set_data_bittiming(struct net_device *ndev)
627{
628	struct peak_canfd_priv *priv = netdev_priv(ndev);
629
630	return pucan_set_timing_fast(priv, &priv->can.data_bittiming);
631}
632
633static int peak_canfd_close(struct net_device *ndev)
634{
635	struct peak_canfd_priv *priv = netdev_priv(ndev);
636
637	netif_stop_queue(ndev);
638	peak_canfd_stop(priv);
639	close_candev(ndev);
640
641	return 0;
642}
643
644static netdev_tx_t peak_canfd_start_xmit(struct sk_buff *skb,
645					 struct net_device *ndev)
646{
647	struct peak_canfd_priv *priv = netdev_priv(ndev);
648	struct net_device_stats *stats = &ndev->stats;
649	struct canfd_frame *cf = (struct canfd_frame *)skb->data;
650	struct pucan_tx_msg *msg;
651	u16 msg_size, msg_flags;
652	unsigned long flags;
653	bool should_stop_tx_queue;
654	int room_left;
655	u8 can_dlc;
656
657	if (can_dropped_invalid_skb(ndev, skb))
658		return NETDEV_TX_OK;
659
660	msg_size = ALIGN(sizeof(*msg) + cf->len, 4);
661	msg = priv->alloc_tx_msg(priv, msg_size, &room_left);
662
663	/* should never happen except under bus-off condition and (auto-)restart
664	 * mechanism
665	 */
666	if (!msg) {
667		stats->tx_dropped++;
668		netif_stop_queue(ndev);
669		return NETDEV_TX_BUSY;
670	}
671
672	msg->size = cpu_to_le16(msg_size);
673	msg->type = cpu_to_le16(PUCAN_MSG_CAN_TX);
674	msg_flags = 0;
675
676	if (cf->can_id & CAN_EFF_FLAG) {
677		msg_flags |= PUCAN_MSG_EXT_ID;
678		msg->can_id = cpu_to_le32(cf->can_id & CAN_EFF_MASK);
679	} else {
680		msg->can_id = cpu_to_le32(cf->can_id & CAN_SFF_MASK);
681	}
682
683	if (can_is_canfd_skb(skb)) {
684		/* CAN FD frame format */
685		can_dlc = can_len2dlc(cf->len);
686
687		msg_flags |= PUCAN_MSG_EXT_DATA_LEN;
688
689		if (cf->flags & CANFD_BRS)
690			msg_flags |= PUCAN_MSG_BITRATE_SWITCH;
691
692		if (cf->flags & CANFD_ESI)
693			msg_flags |= PUCAN_MSG_ERROR_STATE_IND;
694	} else {
695		/* CAN 2.0 frame format */
696		can_dlc = cf->len;
697
698		if (cf->can_id & CAN_RTR_FLAG)
699			msg_flags |= PUCAN_MSG_RTR;
700	}
701
702	/* always ask loopback for echo management */
703	msg_flags |= PUCAN_MSG_LOOPED_BACK;
704
705	/* set driver specific bit to differentiate with application loopback */
706	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
707		msg_flags |= PUCAN_MSG_SELF_RECEIVE;
708
709	msg->flags = cpu_to_le16(msg_flags);
710	msg->channel_dlc = PUCAN_MSG_CHANNEL_DLC(priv->index, can_dlc);
711	memcpy(msg->d, cf->data, cf->len);
712
713	/* struct msg client field is used as an index in the echo skbs ring */
714	msg->client = priv->echo_idx;
715
716	spin_lock_irqsave(&priv->echo_lock, flags);
717
718	/* prepare and save echo skb in internal slot */
719	can_put_echo_skb(skb, ndev, priv->echo_idx);
720
721	/* move echo index to the next slot */
722	priv->echo_idx = (priv->echo_idx + 1) % priv->can.echo_skb_max;
723
724	/* if next slot is not free, stop network queue (no slot free in echo
725	 * skb ring means that the controller did not write these frames on
726	 * the bus: no need to continue).
727	 */
728	should_stop_tx_queue = !!(priv->can.echo_skb[priv->echo_idx]);
729
730	/* stop network tx queue if not enough room to save one more msg too */
731	if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
732		should_stop_tx_queue |= (room_left <
733					(sizeof(*msg) + CANFD_MAX_DLEN));
734	else
735		should_stop_tx_queue |= (room_left <
736					(sizeof(*msg) + CAN_MAX_DLEN));
737
738	if (should_stop_tx_queue)
739		netif_stop_queue(ndev);
740
741	spin_unlock_irqrestore(&priv->echo_lock, flags);
742
743	/* write the skb on the interface */
744	priv->write_tx_msg(priv, msg);
745
746	return NETDEV_TX_OK;
747}
748
749static const struct net_device_ops peak_canfd_netdev_ops = {
750	.ndo_open = peak_canfd_open,
751	.ndo_stop = peak_canfd_close,
752	.ndo_start_xmit = peak_canfd_start_xmit,
753	.ndo_change_mtu = can_change_mtu,
754};
755
756struct net_device *alloc_peak_canfd_dev(int sizeof_priv, int index,
757					int echo_skb_max)
758{
759	struct net_device *ndev;
760	struct peak_canfd_priv *priv;
761
762	/* we DO support local echo */
763	if (echo_skb_max < 0)
764		echo_skb_max = PCANFD_ECHO_SKB_MAX;
765
766	/* allocate the candev object */
767	ndev = alloc_candev(sizeof_priv, echo_skb_max);
768	if (!ndev)
769		return NULL;
770
771	priv = netdev_priv(ndev);
772
773	/* complete now socket-can initialization side */
774	priv->can.state = CAN_STATE_STOPPED;
775	priv->can.bittiming_const = &peak_canfd_nominal_const;
776	priv->can.data_bittiming_const = &peak_canfd_data_const;
777
778	priv->can.do_set_mode = peak_canfd_set_mode;
779	priv->can.do_get_berr_counter = peak_canfd_get_berr_counter;
780	priv->can.do_set_bittiming = peak_canfd_set_bittiming;
781	priv->can.do_set_data_bittiming = peak_canfd_set_data_bittiming;
782	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
783				       CAN_CTRLMODE_LISTENONLY |
784				       CAN_CTRLMODE_3_SAMPLES |
785				       CAN_CTRLMODE_FD |
786				       CAN_CTRLMODE_FD_NON_ISO |
787				       CAN_CTRLMODE_BERR_REPORTING;
788
789	priv->ndev = ndev;
790	priv->index = index;
791	priv->cmd_len = 0;
792	spin_lock_init(&priv->echo_lock);
793
794	ndev->flags |= IFF_ECHO;
795	ndev->netdev_ops = &peak_canfd_netdev_ops;
796	ndev->dev_id = index;
797
798	return ndev;
799}
800