mscan.c revision 622ed7e9cfa931cefc423562d414cb6cd0b08991 
1/*
2 * CAN bus driver for the alone generic (as possible as) MSCAN controller.
3 *
4 * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>,
5 *                         Varma Electronics Oy
6 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
7 * Copytight (C) 2008-2009 Pengutronix <kernel@pengutronix.de>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the version 2 of the GNU General Public License
11 * as published by the Free Software Foundation
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21 */
22
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/interrupt.h>
26#include <linux/delay.h>
27#include <linux/netdevice.h>
28#include <linux/if_arp.h>
29#include <linux/if_ether.h>
30#include <linux/list.h>
31#include <linux/can.h>
32#include <linux/can/dev.h>
33#include <linux/can/error.h>
34#include <linux/io.h>
35
36#include "mscan.h"
37
38static struct can_bittiming_const mscan_bittiming_const = {
39	.name = "mscan",
40	.tseg1_min = 4,
41	.tseg1_max = 16,
42	.tseg2_min = 2,
43	.tseg2_max = 8,
44	.sjw_max = 4,
45	.brp_min = 1,
46	.brp_max = 64,
47	.brp_inc = 1,
48};
49
50struct mscan_state {
51	u8 mode;
52	u8 canrier;
53	u8 cantier;
54};
55
56static enum can_state state_map[] = {
57	CAN_STATE_ERROR_ACTIVE,
58	CAN_STATE_ERROR_WARNING,
59	CAN_STATE_ERROR_PASSIVE,
60	CAN_STATE_BUS_OFF
61};
62
63static int mscan_set_mode(struct net_device *dev, u8 mode)
64{
65	struct mscan_priv *priv = netdev_priv(dev);
66	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
67	int ret = 0;
68	int i;
69	u8 canctl1;
70
71	if (mode != MSCAN_NORMAL_MODE) {
72
73		if (priv->tx_active) {
74			/* Abort transfers before going to sleep */#
75			out_8(&regs->cantarq, priv->tx_active);
76			/* Suppress TX done interrupts */
77			out_8(&regs->cantier, 0);
78		}
79
80		canctl1 = in_8(&regs->canctl1);
81		if ((mode & MSCAN_SLPRQ) && (canctl1 & MSCAN_SLPAK) == 0) {
82			out_8(&regs->canctl0,
83			      in_8(&regs->canctl0) | MSCAN_SLPRQ);
84			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
85				if (in_8(&regs->canctl1) & MSCAN_SLPAK)
86					break;
87				udelay(100);
88			}
89			/*
90			 * The mscan controller will fail to enter sleep mode,
91			 * while there are irregular activities on bus, like
92			 * somebody keeps retransmitting. This behavior is
93			 * undocumented and seems to differ between mscan built
94			 * in mpc5200b and mpc5200. We proceed in that case,
95			 * since otherwise the slprq will be kept set and the
96			 * controller will get stuck. NOTE: INITRQ or CSWAI
97			 * will abort all active transmit actions, if still
98			 * any, at once.
99			 */
100			if (i >= MSCAN_SET_MODE_RETRIES)
101				dev_dbg(dev->dev.parent,
102					"device failed to enter sleep mode. "
103					"We proceed anyhow.\n");
104			else
105				priv->can.state = CAN_STATE_SLEEPING;
106		}
107
108		if ((mode & MSCAN_INITRQ) && (canctl1 & MSCAN_INITAK) == 0) {
109			out_8(&regs->canctl0,
110			      in_8(&regs->canctl0) | MSCAN_INITRQ);
111			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
112				if (in_8(&regs->canctl1) & MSCAN_INITAK)
113					break;
114			}
115			if (i >= MSCAN_SET_MODE_RETRIES)
116				ret = -ENODEV;
117		}
118		if (!ret)
119			priv->can.state = CAN_STATE_STOPPED;
120
121		if (mode & MSCAN_CSWAI)
122			out_8(&regs->canctl0,
123			      in_8(&regs->canctl0) | MSCAN_CSWAI);
124
125	} else {
126		canctl1 = in_8(&regs->canctl1);
127		if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
128			out_8(&regs->canctl0, in_8(&regs->canctl0) &
129			      ~(MSCAN_SLPRQ | MSCAN_INITRQ));
130			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
131				canctl1 = in_8(&regs->canctl1);
132				if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))
133					break;
134			}
135			if (i >= MSCAN_SET_MODE_RETRIES)
136				ret = -ENODEV;
137			else
138				priv->can.state = CAN_STATE_ERROR_ACTIVE;
139		}
140	}
141	return ret;
142}
143
144static int mscan_start(struct net_device *dev)
145{
146	struct mscan_priv *priv = netdev_priv(dev);
147	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
148	u8 canrflg;
149	int err;
150
151	out_8(&regs->canrier, 0);
152
153	INIT_LIST_HEAD(&priv->tx_head);
154	priv->prev_buf_id = 0;
155	priv->cur_pri = 0;
156	priv->tx_active = 0;
157	priv->shadow_canrier = 0;
158	priv->flags = 0;
159
160	err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);
161	if (err)
162		return err;
163
164	canrflg = in_8(&regs->canrflg);
165	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
166	priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg),
167				    MSCAN_STATE_TX(canrflg))];
168	out_8(&regs->cantier, 0);
169
170	/* Enable receive interrupts. */
171	out_8(&regs->canrier, MSCAN_OVRIE | MSCAN_RXFIE | MSCAN_CSCIE |
172	      MSCAN_RSTATE1 | MSCAN_RSTATE0 | MSCAN_TSTATE1 | MSCAN_TSTATE0);
173
174	return 0;
175}
176
177static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
178{
179	struct can_frame *frame = (struct can_frame *)skb->data;
180	struct mscan_priv *priv = netdev_priv(dev);
181	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
182	int i, rtr, buf_id;
183	u32 can_id;
184
185	if (frame->can_dlc > 8)
186		return -EINVAL;
187
188	out_8(&regs->cantier, 0);
189
190	i = ~priv->tx_active & MSCAN_TXE;
191	buf_id = ffs(i) - 1;
192	switch (hweight8(i)) {
193	case 0:
194		netif_stop_queue(dev);
195		dev_err(dev->dev.parent, "Tx Ring full when queue awake!\n");
196		return NETDEV_TX_BUSY;
197	case 1:
198		/*
199		 * if buf_id < 3, then current frame will be send out of order,
200		 * since buffer with lower id have higher priority (hell..)
201		 */
202		netif_stop_queue(dev);
203	case 2:
204		if (buf_id < priv->prev_buf_id) {
205			priv->cur_pri++;
206			if (priv->cur_pri == 0xff) {
207				set_bit(F_TX_WAIT_ALL, &priv->flags);
208				netif_stop_queue(dev);
209			}
210		}
211		set_bit(F_TX_PROGRESS, &priv->flags);
212		break;
213	}
214	priv->prev_buf_id = buf_id;
215	out_8(&regs->cantbsel, i);
216
217	rtr = frame->can_id & CAN_RTR_FLAG;
218
219	if (frame->can_id & CAN_EFF_FLAG) {
220		can_id = (frame->can_id & CAN_EFF_MASK) << 1;
221		if (rtr)
222			can_id |= 1;
223		out_be16(&regs->tx.idr3_2, can_id);
224
225		can_id >>= 16;
226		can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0) | (3 << 3);
227	} else {
228		can_id = (frame->can_id & CAN_SFF_MASK) << 5;
229		if (rtr)
230			can_id |= 1 << 4;
231	}
232	out_be16(&regs->tx.idr1_0, can_id);
233
234	if (!rtr) {
235		void __iomem *data = &regs->tx.dsr1_0;
236		u16 *payload = (u16 *) frame->data;
237		/* It is safe to write into dsr[dlc+1] */
238		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
239			out_be16(data, *payload++);
240			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
241		}
242	}
243
244	out_8(&regs->tx.dlr, frame->can_dlc);
245	out_8(&regs->tx.tbpr, priv->cur_pri);
246
247	/* Start transmission. */
248	out_8(&regs->cantflg, 1 << buf_id);
249
250	if (!test_bit(F_TX_PROGRESS, &priv->flags))
251		dev->trans_start = jiffies;
252
253	list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);
254
255	can_put_echo_skb(skb, dev, buf_id);
256
257	/* Enable interrupt. */
258	priv->tx_active |= 1 << buf_id;
259	out_8(&regs->cantier, priv->tx_active);
260
261	return NETDEV_TX_OK;
262}
263
264/* This function returns the old state to see where we came from */
265static enum can_state check_set_state(struct net_device *dev, u8 canrflg)
266{
267	struct mscan_priv *priv = netdev_priv(dev);
268	enum can_state state, old_state = priv->can.state;
269
270	if (canrflg & MSCAN_CSCIF && old_state <= CAN_STATE_BUS_OFF) {
271		state = state_map[max(MSCAN_STATE_RX(canrflg),
272				      MSCAN_STATE_TX(canrflg))];
273		priv->can.state = state;
274	}
275	return old_state;
276}
277
278static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
279{
280	struct mscan_priv *priv = netdev_priv(dev);
281	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
282	u32 can_id;
283	int i;
284
285	can_id = in_be16(&regs->rx.idr1_0);
286	if (can_id & (1 << 3)) {
287		frame->can_id = CAN_EFF_FLAG;
288		can_id = ((can_id << 16) | in_be16(&regs->rx.idr3_2));
289		can_id = ((can_id & 0xffe00000) |
290			  ((can_id & 0x7ffff) << 2)) >> 2;
291	} else {
292		can_id >>= 4;
293		frame->can_id = 0;
294	}
295
296	frame->can_id |= can_id >> 1;
297	if (can_id & 1)
298		frame->can_id |= CAN_RTR_FLAG;
299	frame->can_dlc = in_8(&regs->rx.dlr) & 0xf;
300
301	if (!(frame->can_id & CAN_RTR_FLAG)) {
302		void __iomem *data = &regs->rx.dsr1_0;
303		u16 *payload = (u16 *) frame->data;
304		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
305			*payload++ = in_be16(data);
306			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
307		}
308	}
309
310	out_8(&regs->canrflg, MSCAN_RXF);
311}
312
313static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
314				u8 canrflg)
315{
316	struct mscan_priv *priv = netdev_priv(dev);
317	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
318	struct net_device_stats *stats = &dev->stats;
319	enum can_state old_state;
320
321	dev_dbg(dev->dev.parent, "error interrupt (canrflg=%#x)\n", canrflg);
322	frame->can_id = CAN_ERR_FLAG;
323
324	if (canrflg & MSCAN_OVRIF) {
325		frame->can_id |= CAN_ERR_CRTL;
326		frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
327		stats->rx_over_errors++;
328		stats->rx_errors++;
329	} else
330		frame->data[1] = 0;
331
332	old_state = check_set_state(dev, canrflg);
333	/* State changed */
334	if (old_state != priv->can.state) {
335		switch (priv->can.state) {
336		case CAN_STATE_ERROR_WARNING:
337			frame->can_id |= CAN_ERR_CRTL;
338			priv->can.can_stats.error_warning++;
339			if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
340			    (canrflg & MSCAN_RSTAT_MSK))
341				frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
342
343			if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
344			    (canrflg & MSCAN_TSTAT_MSK))
345				frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
346			break;
347		case CAN_STATE_ERROR_PASSIVE:
348			frame->can_id |= CAN_ERR_CRTL;
349			priv->can.can_stats.error_passive++;
350			frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
351			break;
352		case CAN_STATE_BUS_OFF:
353			frame->can_id |= CAN_ERR_BUSOFF;
354			/*
355			 * The MSCAN on the MPC5200 does recover from bus-off
356			 * automatically. To avoid that we stop the chip doing
357			 * a light-weight stop (we are in irq-context).
358			 */
359			out_8(&regs->cantier, 0);
360			out_8(&regs->canrier, 0);
361			out_8(&regs->canctl0, in_8(&regs->canctl0) |
362				MSCAN_SLPRQ | MSCAN_INITRQ);
363			can_bus_off(dev);
364			break;
365		default:
366			break;
367		}
368	}
369	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
370	frame->can_dlc = CAN_ERR_DLC;
371	out_8(&regs->canrflg, MSCAN_ERR_IF);
372}
373
374static int mscan_rx_poll(struct napi_struct *napi, int quota)
375{
376	struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
377	struct net_device *dev = napi->dev;
378	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
379	struct net_device_stats *stats = &dev->stats;
380	int npackets = 0;
381	int ret = 1;
382	struct sk_buff *skb;
383	struct can_frame *frame;
384	u8 canrflg;
385
386	while (npackets < quota && ((canrflg = in_8(&regs->canrflg)) &
387				    (MSCAN_RXF | MSCAN_ERR_IF))) {
388
389		skb = alloc_can_skb(dev, &frame);
390		if (!skb) {
391			if (printk_ratelimit())
392				dev_notice(dev->dev.parent, "packet dropped\n");
393			stats->rx_dropped++;
394			out_8(&regs->canrflg, canrflg);
395			continue;
396		}
397
398		if (canrflg & MSCAN_RXF)
399			mscan_get_rx_frame(dev, frame);
400		 else if (canrflg & MSCAN_ERR_IF)
401			mscan_get_err_frame(dev, frame, canrflg);
402
403		stats->rx_packets++;
404		stats->rx_bytes += frame->can_dlc;
405		npackets++;
406		netif_receive_skb(skb);
407	}
408
409	if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
410		napi_complete(&priv->napi);
411		clear_bit(F_RX_PROGRESS, &priv->flags);
412		if (priv->can.state < CAN_STATE_BUS_OFF)
413			out_8(&regs->canrier, priv->shadow_canrier);
414		ret = 0;
415	}
416	return ret;
417}
418
419static irqreturn_t mscan_isr(int irq, void *dev_id)
420{
421	struct net_device *dev = (struct net_device *)dev_id;
422	struct mscan_priv *priv = netdev_priv(dev);
423	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
424	struct net_device_stats *stats = &dev->stats;
425	u8 cantier, cantflg, canrflg;
426	irqreturn_t ret = IRQ_NONE;
427
428	cantier = in_8(&regs->cantier) & MSCAN_TXE;
429	cantflg = in_8(&regs->cantflg) & cantier;
430
431	if (cantier && cantflg) {
432
433		struct list_head *tmp, *pos;
434
435		list_for_each_safe(pos, tmp, &priv->tx_head) {
436			struct tx_queue_entry *entry =
437			    list_entry(pos, struct tx_queue_entry, list);
438			u8 mask = entry->mask;
439
440			if (!(cantflg & mask))
441				continue;
442
443			out_8(&regs->cantbsel, mask);
444			stats->tx_bytes += in_8(&regs->tx.dlr);
445			stats->tx_packets++;
446			can_get_echo_skb(dev, entry->id);
447			priv->tx_active &= ~mask;
448			list_del(pos);
449		}
450
451		if (list_empty(&priv->tx_head)) {
452			clear_bit(F_TX_WAIT_ALL, &priv->flags);
453			clear_bit(F_TX_PROGRESS, &priv->flags);
454			priv->cur_pri = 0;
455		} else
456			dev->trans_start = jiffies;
457
458		if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
459			netif_wake_queue(dev);
460
461		out_8(&regs->cantier, priv->tx_active);
462		ret = IRQ_HANDLED;
463	}
464
465	canrflg = in_8(&regs->canrflg);
466	if ((canrflg & ~MSCAN_STAT_MSK) &&
467	    !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
468		if (canrflg & ~MSCAN_STAT_MSK) {
469			priv->shadow_canrier = in_8(&regs->canrier);
470			out_8(&regs->canrier, 0);
471			napi_schedule(&priv->napi);
472			ret = IRQ_HANDLED;
473		} else
474			clear_bit(F_RX_PROGRESS, &priv->flags);
475	}
476	return ret;
477}
478
479static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
480{
481
482	struct mscan_priv *priv = netdev_priv(dev);
483	int ret = 0;
484
485	if (!priv->open_time)
486		return -EINVAL;
487
488	switch (mode) {
489	case CAN_MODE_SLEEP:
490	case CAN_MODE_STOP:
491		netif_stop_queue(dev);
492		mscan_set_mode(dev,
493			       (mode ==
494				CAN_MODE_STOP) ? MSCAN_INIT_MODE :
495			       MSCAN_SLEEP_MODE);
496		break;
497	case CAN_MODE_START:
498		if (priv->can.state <= CAN_STATE_BUS_OFF)
499			mscan_set_mode(dev, MSCAN_INIT_MODE);
500		ret = mscan_start(dev);
501		if (ret)
502			break;
503		if (netif_queue_stopped(dev))
504			netif_wake_queue(dev);
505		break;
506
507	default:
508		ret = -EOPNOTSUPP;
509		break;
510	}
511	return ret;
512}
513
514static int mscan_do_set_bittiming(struct net_device *dev)
515{
516	struct mscan_priv *priv = netdev_priv(dev);
517	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
518	struct can_bittiming *bt = &priv->can.bittiming;
519	u8 btr0, btr1;
520
521	btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
522	btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
523		BTR1_SET_TSEG2(bt->phase_seg2) |
524		BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));
525
526	dev_info(dev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
527		btr0, btr1);
528
529	out_8(&regs->canbtr0, btr0);
530	out_8(&regs->canbtr1, btr1);
531
532	return 0;
533}
534
535static int mscan_open(struct net_device *dev)
536{
537	int ret;
538	struct mscan_priv *priv = netdev_priv(dev);
539	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
540
541	/* common open */
542	ret = open_candev(dev);
543	if (ret)
544		return ret;
545
546	napi_enable(&priv->napi);
547
548	ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
549	if (ret < 0) {
550		napi_disable(&priv->napi);
551		printk(KERN_ERR "%s - failed to attach interrupt\n",
552		       dev->name);
553		return ret;
554	}
555
556	priv->open_time = jiffies;
557
558	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_LISTEN);
559
560	ret = mscan_start(dev);
561	if (ret)
562		return ret;
563
564	netif_start_queue(dev);
565
566	return 0;
567}
568
569static int mscan_close(struct net_device *dev)
570{
571	struct mscan_priv *priv = netdev_priv(dev);
572	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
573
574	netif_stop_queue(dev);
575	napi_disable(&priv->napi);
576
577	out_8(&regs->cantier, 0);
578	out_8(&regs->canrier, 0);
579	mscan_set_mode(dev, MSCAN_INIT_MODE);
580	close_candev(dev);
581	free_irq(dev->irq, dev);
582	priv->open_time = 0;
583
584	return 0;
585}
586
587static const struct net_device_ops mscan_netdev_ops = {
588       .ndo_open               = mscan_open,
589       .ndo_stop               = mscan_close,
590       .ndo_start_xmit         = mscan_start_xmit,
591};
592
593int register_mscandev(struct net_device *dev, int clock_src)
594{
595	struct mscan_priv *priv = netdev_priv(dev);
596	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
597	u8 ctl1;
598
599	ctl1 = in_8(&regs->canctl1);
600	if (clock_src)
601		ctl1 |= MSCAN_CLKSRC;
602	else
603		ctl1 &= ~MSCAN_CLKSRC;
604
605	ctl1 |= MSCAN_CANE;
606	out_8(&regs->canctl1, ctl1);
607	udelay(100);
608
609	/* acceptance mask/acceptance code (accept everything) */
610	out_be16(&regs->canidar1_0, 0);
611	out_be16(&regs->canidar3_2, 0);
612	out_be16(&regs->canidar5_4, 0);
613	out_be16(&regs->canidar7_6, 0);
614
615	out_be16(&regs->canidmr1_0, 0xffff);
616	out_be16(&regs->canidmr3_2, 0xffff);
617	out_be16(&regs->canidmr5_4, 0xffff);
618	out_be16(&regs->canidmr7_6, 0xffff);
619	/* Two 32 bit Acceptance Filters */
620	out_8(&regs->canidac, MSCAN_AF_32BIT);
621
622	mscan_set_mode(dev, MSCAN_INIT_MODE);
623
624	return register_candev(dev);
625}
626EXPORT_SYMBOL_GPL(register_mscandev);
627
628void unregister_mscandev(struct net_device *dev)
629{
630	struct mscan_priv *priv = netdev_priv(dev);
631	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
632	mscan_set_mode(dev, MSCAN_INIT_MODE);
633	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_CANE);
634	unregister_candev(dev);
635}
636EXPORT_SYMBOL_GPL(unregister_mscandev);
637
638struct net_device *alloc_mscandev(void)
639{
640	struct net_device *dev;
641	struct mscan_priv *priv;
642	int i;
643
644	dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
645	if (!dev)
646		return NULL;
647	priv = netdev_priv(dev);
648
649	dev->netdev_ops = &mscan_netdev_ops;
650
651	dev->flags |= IFF_ECHO;	/* we support local echo */
652
653	netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);
654
655	priv->can.bittiming_const = &mscan_bittiming_const;
656	priv->can.do_set_bittiming = mscan_do_set_bittiming;
657	priv->can.do_set_mode = mscan_do_set_mode;
658
659	for (i = 0; i < TX_QUEUE_SIZE; i++) {
660		priv->tx_queue[i].id = i;
661		priv->tx_queue[i].mask = 1 << i;
662	}
663
664	return dev;
665}
666EXPORT_SYMBOL_GPL(alloc_mscandev);
667
668MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
669MODULE_LICENSE("GPL v2");
670MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");
671