mscan.c revision 0285e7ceaaec9ef2d2e74dd37e2b557c0e017b5c 
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		if (priv->tx_active) {
73			/* Abort transfers before going to sleep */#
74			out_8(&regs->cantarq, priv->tx_active);
75			/* Suppress TX done interrupts */
76			out_8(&regs->cantier, 0);
77		}
78
79		canctl1 = in_8(&regs->canctl1);
80		if ((mode & MSCAN_SLPRQ) && !(canctl1 & MSCAN_SLPAK)) {
81			out_8(&regs->canctl0,
82			      in_8(&regs->canctl0) | MSCAN_SLPRQ);
83			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
84				if (in_8(&regs->canctl1) & MSCAN_SLPAK)
85					break;
86				udelay(100);
87			}
88			/*
89			 * The mscan controller will fail to enter sleep mode,
90			 * while there are irregular activities on bus, like
91			 * somebody keeps retransmitting. This behavior is
92			 * undocumented and seems to differ between mscan built
93			 * in mpc5200b and mpc5200. We proceed in that case,
94			 * since otherwise the slprq will be kept set and the
95			 * controller will get stuck. NOTE: INITRQ or CSWAI
96			 * will abort all active transmit actions, if still
97			 * any, at once.
98			 */
99			if (i >= MSCAN_SET_MODE_RETRIES)
100				dev_dbg(dev->dev.parent,
101					"device failed to enter sleep mode. "
102					"We proceed anyhow.\n");
103			else
104				priv->can.state = CAN_STATE_SLEEPING;
105		}
106
107		if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) {
108			out_8(&regs->canctl0,
109			      in_8(&regs->canctl0) | MSCAN_INITRQ);
110			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
111				if (in_8(&regs->canctl1) & MSCAN_INITAK)
112					break;
113			}
114			if (i >= MSCAN_SET_MODE_RETRIES)
115				ret = -ENODEV;
116		}
117		if (!ret)
118			priv->can.state = CAN_STATE_STOPPED;
119
120		if (mode & MSCAN_CSWAI)
121			out_8(&regs->canctl0,
122			      in_8(&regs->canctl0) | MSCAN_CSWAI);
123
124	} else {
125		canctl1 = in_8(&regs->canctl1);
126		if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
127			out_8(&regs->canctl0, in_8(&regs->canctl0) &
128			      ~(MSCAN_SLPRQ | MSCAN_INITRQ));
129			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
130				canctl1 = in_8(&regs->canctl1);
131				if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))
132					break;
133			}
134			if (i >= MSCAN_SET_MODE_RETRIES)
135				ret = -ENODEV;
136			else
137				priv->can.state = CAN_STATE_ERROR_ACTIVE;
138		}
139	}
140	return ret;
141}
142
143static int mscan_start(struct net_device *dev)
144{
145	struct mscan_priv *priv = netdev_priv(dev);
146	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
147	u8 canrflg;
148	int err;
149
150	out_8(&regs->canrier, 0);
151
152	INIT_LIST_HEAD(&priv->tx_head);
153	priv->prev_buf_id = 0;
154	priv->cur_pri = 0;
155	priv->tx_active = 0;
156	priv->shadow_canrier = 0;
157	priv->flags = 0;
158
159	err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);
160	if (err)
161		return err;
162
163	canrflg = in_8(&regs->canrflg);
164	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
165	priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg),
166				    MSCAN_STATE_TX(canrflg))];
167	out_8(&regs->cantier, 0);
168
169	/* Enable receive interrupts. */
170	out_8(&regs->canrier, MSCAN_OVRIE | MSCAN_RXFIE | MSCAN_CSCIE |
171	      MSCAN_RSTATE1 | MSCAN_RSTATE0 | MSCAN_TSTATE1 | MSCAN_TSTATE0);
172
173	return 0;
174}
175
176static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
177{
178	struct can_frame *frame = (struct can_frame *)skb->data;
179	struct mscan_priv *priv = netdev_priv(dev);
180	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
181	int i, rtr, buf_id;
182	u32 can_id;
183
184	if (frame->can_dlc > 8)
185		return -EINVAL;
186
187	out_8(&regs->cantier, 0);
188
189	i = ~priv->tx_active & MSCAN_TXE;
190	buf_id = ffs(i) - 1;
191	switch (hweight8(i)) {
192	case 0:
193		netif_stop_queue(dev);
194		dev_err(dev->dev.parent, "Tx Ring full when queue awake!\n");
195		return NETDEV_TX_BUSY;
196	case 1:
197		/*
198		 * if buf_id < 3, then current frame will be send out of order,
199		 * since buffer with lower id have higher priority (hell..)
200		 */
201		netif_stop_queue(dev);
202	case 2:
203		if (buf_id < priv->prev_buf_id) {
204			priv->cur_pri++;
205			if (priv->cur_pri == 0xff) {
206				set_bit(F_TX_WAIT_ALL, &priv->flags);
207				netif_stop_queue(dev);
208			}
209		}
210		set_bit(F_TX_PROGRESS, &priv->flags);
211		break;
212	}
213	priv->prev_buf_id = buf_id;
214	out_8(&regs->cantbsel, i);
215
216	rtr = frame->can_id & CAN_RTR_FLAG;
217
218	if (frame->can_id & CAN_EFF_FLAG) {
219		can_id = (frame->can_id & CAN_EFF_MASK) << 1;
220		if (rtr)
221			can_id |= 1;
222		out_be16(&regs->tx.idr3_2, can_id);
223
224		can_id >>= 16;
225		can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0) | (3 << 3);
226	} else {
227		can_id = (frame->can_id & CAN_SFF_MASK) << 5;
228		if (rtr)
229			can_id |= 1 << 4;
230	}
231	out_be16(&regs->tx.idr1_0, can_id);
232
233	if (!rtr) {
234		void __iomem *data = &regs->tx.dsr1_0;
235		u16 *payload = (u16 *)frame->data;
236
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
305		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
306			*payload++ = in_be16(data);
307			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
308		}
309	}
310
311	out_8(&regs->canrflg, MSCAN_RXF);
312}
313
314static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
315				u8 canrflg)
316{
317	struct mscan_priv *priv = netdev_priv(dev);
318	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
319	struct net_device_stats *stats = &dev->stats;
320	enum can_state old_state;
321
322	dev_dbg(dev->dev.parent, "error interrupt (canrflg=%#x)\n", canrflg);
323	frame->can_id = CAN_ERR_FLAG;
324
325	if (canrflg & MSCAN_OVRIF) {
326		frame->can_id |= CAN_ERR_CRTL;
327		frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
328		stats->rx_over_errors++;
329		stats->rx_errors++;
330	} else {
331		frame->data[1] = 0;
332	}
333
334	old_state = check_set_state(dev, canrflg);
335	/* State changed */
336	if (old_state != priv->can.state) {
337		switch (priv->can.state) {
338		case CAN_STATE_ERROR_WARNING:
339			frame->can_id |= CAN_ERR_CRTL;
340			priv->can.can_stats.error_warning++;
341			if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
342			    (canrflg & MSCAN_RSTAT_MSK))
343				frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
344			if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
345			    (canrflg & MSCAN_TSTAT_MSK))
346				frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
347			break;
348		case CAN_STATE_ERROR_PASSIVE:
349			frame->can_id |= CAN_ERR_CRTL;
350			priv->can.can_stats.error_passive++;
351			frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
352			break;
353		case CAN_STATE_BUS_OFF:
354			frame->can_id |= CAN_ERR_BUSOFF;
355			/*
356			 * The MSCAN on the MPC5200 does recover from bus-off
357			 * automatically. To avoid that we stop the chip doing
358			 * a light-weight stop (we are in irq-context).
359			 */
360			out_8(&regs->cantier, 0);
361			out_8(&regs->canrier, 0);
362			out_8(&regs->canctl0, in_8(&regs->canctl0) |
363				MSCAN_SLPRQ | MSCAN_INITRQ);
364			can_bus_off(dev);
365			break;
366		default:
367			break;
368		}
369	}
370	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
371	frame->can_dlc = CAN_ERR_DLC;
372	out_8(&regs->canrflg, MSCAN_ERR_IF);
373}
374
375static int mscan_rx_poll(struct napi_struct *napi, int quota)
376{
377	struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
378	struct net_device *dev = napi->dev;
379	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
380	struct net_device_stats *stats = &dev->stats;
381	int npackets = 0;
382	int ret = 1;
383	struct sk_buff *skb;
384	struct can_frame *frame;
385	u8 canrflg;
386
387	while (npackets < quota && ((canrflg = in_8(&regs->canrflg)) &
388				    (MSCAN_RXF | MSCAN_ERR_IF))) {
389
390		skb = alloc_can_skb(dev, &frame);
391		if (!skb) {
392			if (printk_ratelimit())
393				dev_notice(dev->dev.parent, "packet dropped\n");
394			stats->rx_dropped++;
395			out_8(&regs->canrflg, canrflg);
396			continue;
397		}
398
399		if (canrflg & MSCAN_RXF)
400			mscan_get_rx_frame(dev, frame);
401		else if (canrflg & MSCAN_ERR_IF)
402			mscan_get_err_frame(dev, frame, canrflg);
403
404		stats->rx_packets++;
405		stats->rx_bytes += frame->can_dlc;
406		npackets++;
407		netif_receive_skb(skb);
408	}
409
410	if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
411		napi_complete(&priv->napi);
412		clear_bit(F_RX_PROGRESS, &priv->flags);
413		if (priv->can.state < CAN_STATE_BUS_OFF)
414			out_8(&regs->canrier, priv->shadow_canrier);
415		ret = 0;
416	}
417	return ret;
418}
419
420static irqreturn_t mscan_isr(int irq, void *dev_id)
421{
422	struct net_device *dev = (struct net_device *)dev_id;
423	struct mscan_priv *priv = netdev_priv(dev);
424	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
425	struct net_device_stats *stats = &dev->stats;
426	u8 cantier, cantflg, canrflg;
427	irqreturn_t ret = IRQ_NONE;
428
429	cantier = in_8(&regs->cantier) & MSCAN_TXE;
430	cantflg = in_8(&regs->cantflg) & cantier;
431
432	if (cantier && cantflg) {
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
459		if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
460			netif_wake_queue(dev);
461
462		out_8(&regs->cantier, priv->tx_active);
463		ret = IRQ_HANDLED;
464	}
465
466	canrflg = in_8(&regs->canrflg);
467	if ((canrflg & ~MSCAN_STAT_MSK) &&
468	    !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
469		if (canrflg & ~MSCAN_STAT_MSK) {
470			priv->shadow_canrier = in_8(&regs->canrier);
471			out_8(&regs->canrier, 0);
472			napi_schedule(&priv->napi);
473			ret = IRQ_HANDLED;
474		} else {
475			clear_bit(F_RX_PROGRESS, &priv->flags);
476		}
477	}
478	return ret;
479}
480
481static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
482{
483	struct mscan_priv *priv = netdev_priv(dev);
484	int ret = 0;
485
486	if (!priv->open_time)
487		return -EINVAL;
488
489	switch (mode) {
490	case CAN_MODE_SLEEP:
491	case CAN_MODE_STOP:
492		netif_stop_queue(dev);
493		mscan_set_mode(dev,
494			       (mode ==
495				CAN_MODE_STOP) ? MSCAN_INIT_MODE :
496			       MSCAN_SLEEP_MODE);
497		break;
498	case CAN_MODE_START:
499		if (priv->can.state <= CAN_STATE_BUS_OFF)
500			mscan_set_mode(dev, MSCAN_INIT_MODE);
501		ret = mscan_start(dev);
502		if (ret)
503			break;
504		if (netif_queue_stopped(dev))
505			netif_wake_queue(dev);
506		break;
507
508	default:
509		ret = -EOPNOTSUPP;
510		break;
511	}
512	return ret;
513}
514
515static int mscan_do_set_bittiming(struct net_device *dev)
516{
517	struct mscan_priv *priv = netdev_priv(dev);
518	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
519	struct can_bittiming *bt = &priv->can.bittiming;
520	u8 btr0, btr1;
521
522	btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
523	btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
524		BTR1_SET_TSEG2(bt->phase_seg2) |
525		BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));
526
527	dev_info(dev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
528		btr0, btr1);
529
530	out_8(&regs->canbtr0, btr0);
531	out_8(&regs->canbtr1, btr1);
532
533	return 0;
534}
535
536static int mscan_open(struct net_device *dev)
537{
538	int ret;
539	struct mscan_priv *priv = netdev_priv(dev);
540	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
541
542	/* common open */
543	ret = open_candev(dev);
544	if (ret)
545		return ret;
546
547	napi_enable(&priv->napi);
548
549	ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
550	if (ret < 0) {
551		napi_disable(&priv->napi);
552		printk(KERN_ERR "%s - failed to attach interrupt\n",
553		       dev->name);
554		return ret;
555	}
556
557	priv->open_time = jiffies;
558
559	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_LISTEN);
560
561	ret = mscan_start(dev);
562	if (ret)
563		return ret;
564
565	netif_start_queue(dev);
566
567	return 0;
568}
569
570static int mscan_close(struct net_device *dev)
571{
572	struct mscan_priv *priv = netdev_priv(dev);
573	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
574
575	netif_stop_queue(dev);
576	napi_disable(&priv->napi);
577
578	out_8(&regs->cantier, 0);
579	out_8(&regs->canrier, 0);
580	mscan_set_mode(dev, MSCAN_INIT_MODE);
581	close_candev(dev);
582	free_irq(dev->irq, dev);
583	priv->open_time = 0;
584
585	return 0;
586}
587
588static const struct net_device_ops mscan_netdev_ops = {
589       .ndo_open               = mscan_open,
590       .ndo_stop               = mscan_close,
591       .ndo_start_xmit         = mscan_start_xmit,
592};
593
594int register_mscandev(struct net_device *dev, int clock_src)
595{
596	struct mscan_priv *priv = netdev_priv(dev);
597	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
598	u8 ctl1;
599
600	ctl1 = in_8(&regs->canctl1);
601	if (clock_src)
602		ctl1 |= MSCAN_CLKSRC;
603	else
604		ctl1 &= ~MSCAN_CLKSRC;
605
606	ctl1 |= MSCAN_CANE;
607	out_8(&regs->canctl1, ctl1);
608	udelay(100);
609
610	/* acceptance mask/acceptance code (accept everything) */
611	out_be16(&regs->canidar1_0, 0);
612	out_be16(&regs->canidar3_2, 0);
613	out_be16(&regs->canidar5_4, 0);
614	out_be16(&regs->canidar7_6, 0);
615
616	out_be16(&regs->canidmr1_0, 0xffff);
617	out_be16(&regs->canidmr3_2, 0xffff);
618	out_be16(&regs->canidmr5_4, 0xffff);
619	out_be16(&regs->canidmr7_6, 0xffff);
620	/* Two 32 bit Acceptance Filters */
621	out_8(&regs->canidac, MSCAN_AF_32BIT);
622
623	mscan_set_mode(dev, MSCAN_INIT_MODE);
624
625	return register_candev(dev);
626}
627EXPORT_SYMBOL_GPL(register_mscandev);
628
629void unregister_mscandev(struct net_device *dev)
630{
631	struct mscan_priv *priv = netdev_priv(dev);
632	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
633	mscan_set_mode(dev, MSCAN_INIT_MODE);
634	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_CANE);
635	unregister_candev(dev);
636}
637EXPORT_SYMBOL_GPL(unregister_mscandev);
638
639struct net_device *alloc_mscandev(void)
640{
641	struct net_device *dev;
642	struct mscan_priv *priv;
643	int i;
644
645	dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
646	if (!dev)
647		return NULL;
648	priv = netdev_priv(dev);
649
650	dev->netdev_ops = &mscan_netdev_ops;
651
652	dev->flags |= IFF_ECHO;	/* we support local echo */
653
654	netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);
655
656	priv->can.bittiming_const = &mscan_bittiming_const;
657	priv->can.do_set_bittiming = mscan_do_set_bittiming;
658	priv->can.do_set_mode = mscan_do_set_mode;
659
660	for (i = 0; i < TX_QUEUE_SIZE; i++) {
661		priv->tx_queue[i].id = i;
662		priv->tx_queue[i].mask = 1 << i;
663	}
664
665	return dev;
666}
667EXPORT_SYMBOL_GPL(alloc_mscandev);
668
669MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
670MODULE_LICENSE("GPL v2");
671MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");
672