xref: /openbmc/linux/drivers/net/can/mscan/mscan.c (revision 22fd411a)
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  * Copyright (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/dev.h>
32 #include <linux/can/error.h>
33 #include <linux/io.h>
34 
35 #include "mscan.h"
36 
37 static struct can_bittiming_const mscan_bittiming_const = {
38 	.name = "mscan",
39 	.tseg1_min = 4,
40 	.tseg1_max = 16,
41 	.tseg2_min = 2,
42 	.tseg2_max = 8,
43 	.sjw_max = 4,
44 	.brp_min = 1,
45 	.brp_max = 64,
46 	.brp_inc = 1,
47 };
48 
49 struct mscan_state {
50 	u8 mode;
51 	u8 canrier;
52 	u8 cantier;
53 };
54 
55 static enum can_state state_map[] = {
56 	CAN_STATE_ERROR_ACTIVE,
57 	CAN_STATE_ERROR_WARNING,
58 	CAN_STATE_ERROR_PASSIVE,
59 	CAN_STATE_BUS_OFF
60 };
61 
62 static int mscan_set_mode(struct net_device *dev, u8 mode)
63 {
64 	struct mscan_priv *priv = netdev_priv(dev);
65 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
66 	int ret = 0;
67 	int i;
68 	u8 canctl1;
69 
70 	if (mode != MSCAN_NORMAL_MODE) {
71 		if (priv->tx_active) {
72 			/* Abort transfers before going to sleep */#
73 			out_8(&regs->cantarq, priv->tx_active);
74 			/* Suppress TX done interrupts */
75 			out_8(&regs->cantier, 0);
76 		}
77 
78 		canctl1 = in_8(&regs->canctl1);
79 		if ((mode & MSCAN_SLPRQ) && !(canctl1 & MSCAN_SLPAK)) {
80 			setbits8(&regs->canctl0, MSCAN_SLPRQ);
81 			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
82 				if (in_8(&regs->canctl1) & MSCAN_SLPAK)
83 					break;
84 				udelay(100);
85 			}
86 			/*
87 			 * The mscan controller will fail to enter sleep mode,
88 			 * while there are irregular activities on bus, like
89 			 * somebody keeps retransmitting. This behavior is
90 			 * undocumented and seems to differ between mscan built
91 			 * in mpc5200b and mpc5200. We proceed in that case,
92 			 * since otherwise the slprq will be kept set and the
93 			 * controller will get stuck. NOTE: INITRQ or CSWAI
94 			 * will abort all active transmit actions, if still
95 			 * any, at once.
96 			 */
97 			if (i >= MSCAN_SET_MODE_RETRIES)
98 				dev_dbg(dev->dev.parent,
99 					"device failed to enter sleep mode. "
100 					"We proceed anyhow.\n");
101 			else
102 				priv->can.state = CAN_STATE_SLEEPING;
103 		}
104 
105 		if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) {
106 			setbits8(&regs->canctl0, MSCAN_INITRQ);
107 			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
108 				if (in_8(&regs->canctl1) & MSCAN_INITAK)
109 					break;
110 			}
111 			if (i >= MSCAN_SET_MODE_RETRIES)
112 				ret = -ENODEV;
113 		}
114 		if (!ret)
115 			priv->can.state = CAN_STATE_STOPPED;
116 
117 		if (mode & MSCAN_CSWAI)
118 			setbits8(&regs->canctl0, MSCAN_CSWAI);
119 
120 	} else {
121 		canctl1 = in_8(&regs->canctl1);
122 		if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
123 			clrbits8(&regs->canctl0, MSCAN_SLPRQ | MSCAN_INITRQ);
124 			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
125 				canctl1 = in_8(&regs->canctl1);
126 				if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))
127 					break;
128 			}
129 			if (i >= MSCAN_SET_MODE_RETRIES)
130 				ret = -ENODEV;
131 			else
132 				priv->can.state = CAN_STATE_ERROR_ACTIVE;
133 		}
134 	}
135 	return ret;
136 }
137 
138 static int mscan_start(struct net_device *dev)
139 {
140 	struct mscan_priv *priv = netdev_priv(dev);
141 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
142 	u8 canrflg;
143 	int err;
144 
145 	out_8(&regs->canrier, 0);
146 
147 	INIT_LIST_HEAD(&priv->tx_head);
148 	priv->prev_buf_id = 0;
149 	priv->cur_pri = 0;
150 	priv->tx_active = 0;
151 	priv->shadow_canrier = 0;
152 	priv->flags = 0;
153 
154 	if (priv->type == MSCAN_TYPE_MPC5121) {
155 		/* Clear pending bus-off condition */
156 		if (in_8(&regs->canmisc) & MSCAN_BOHOLD)
157 			out_8(&regs->canmisc, MSCAN_BOHOLD);
158 	}
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_RX_INTS_ENABLE);
172 
173 	return 0;
174 }
175 
176 static int mscan_restart(struct net_device *dev)
177 {
178 	struct mscan_priv *priv = netdev_priv(dev);
179 
180 	if (priv->type == MSCAN_TYPE_MPC5121) {
181 		struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
182 
183 		priv->can.state = CAN_STATE_ERROR_ACTIVE;
184 		WARN(!(in_8(&regs->canmisc) & MSCAN_BOHOLD),
185 		     "bus-off state expected\n");
186 		out_8(&regs->canmisc, MSCAN_BOHOLD);
187 		/* Re-enable receive interrupts. */
188 		out_8(&regs->canrier, MSCAN_RX_INTS_ENABLE);
189 	} else {
190 		if (priv->can.state <= CAN_STATE_BUS_OFF)
191 			mscan_set_mode(dev, MSCAN_INIT_MODE);
192 		return mscan_start(dev);
193 	}
194 
195 	return 0;
196 }
197 
198 static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
199 {
200 	struct can_frame *frame = (struct can_frame *)skb->data;
201 	struct mscan_priv *priv = netdev_priv(dev);
202 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
203 	int i, rtr, buf_id;
204 	u32 can_id;
205 
206 	if (can_dropped_invalid_skb(dev, skb))
207 		return NETDEV_TX_OK;
208 
209 	out_8(&regs->cantier, 0);
210 
211 	i = ~priv->tx_active & MSCAN_TXE;
212 	buf_id = ffs(i) - 1;
213 	switch (hweight8(i)) {
214 	case 0:
215 		netif_stop_queue(dev);
216 		dev_err(dev->dev.parent, "Tx Ring full when queue awake!\n");
217 		return NETDEV_TX_BUSY;
218 	case 1:
219 		/*
220 		 * if buf_id < 3, then current frame will be send out of order,
221 		 * since buffer with lower id have higher priority (hell..)
222 		 */
223 		netif_stop_queue(dev);
224 	case 2:
225 		if (buf_id < priv->prev_buf_id) {
226 			priv->cur_pri++;
227 			if (priv->cur_pri == 0xff) {
228 				set_bit(F_TX_WAIT_ALL, &priv->flags);
229 				netif_stop_queue(dev);
230 			}
231 		}
232 		set_bit(F_TX_PROGRESS, &priv->flags);
233 		break;
234 	}
235 	priv->prev_buf_id = buf_id;
236 	out_8(&regs->cantbsel, i);
237 
238 	rtr = frame->can_id & CAN_RTR_FLAG;
239 
240 	/* RTR is always the lowest bit of interest, then IDs follow */
241 	if (frame->can_id & CAN_EFF_FLAG) {
242 		can_id = (frame->can_id & CAN_EFF_MASK)
243 			 << (MSCAN_EFF_RTR_SHIFT + 1);
244 		if (rtr)
245 			can_id |= 1 << MSCAN_EFF_RTR_SHIFT;
246 		out_be16(&regs->tx.idr3_2, can_id);
247 
248 		can_id >>= 16;
249 		/* EFF_FLAGS are inbetween the IDs :( */
250 		can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0)
251 			 | MSCAN_EFF_FLAGS;
252 	} else {
253 		can_id = (frame->can_id & CAN_SFF_MASK)
254 			 << (MSCAN_SFF_RTR_SHIFT + 1);
255 		if (rtr)
256 			can_id |= 1 << MSCAN_SFF_RTR_SHIFT;
257 	}
258 	out_be16(&regs->tx.idr1_0, can_id);
259 
260 	if (!rtr) {
261 		void __iomem *data = &regs->tx.dsr1_0;
262 		u16 *payload = (u16 *)frame->data;
263 
264 		/* It is safe to write into dsr[dlc+1] */
265 		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
266 			out_be16(data, *payload++);
267 			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
268 		}
269 	}
270 
271 	out_8(&regs->tx.dlr, frame->can_dlc);
272 	out_8(&regs->tx.tbpr, priv->cur_pri);
273 
274 	/* Start transmission. */
275 	out_8(&regs->cantflg, 1 << buf_id);
276 
277 	if (!test_bit(F_TX_PROGRESS, &priv->flags))
278 		dev->trans_start = jiffies;
279 
280 	list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);
281 
282 	can_put_echo_skb(skb, dev, buf_id);
283 
284 	/* Enable interrupt. */
285 	priv->tx_active |= 1 << buf_id;
286 	out_8(&regs->cantier, priv->tx_active);
287 
288 	return NETDEV_TX_OK;
289 }
290 
291 /* This function returns the old state to see where we came from */
292 static enum can_state check_set_state(struct net_device *dev, u8 canrflg)
293 {
294 	struct mscan_priv *priv = netdev_priv(dev);
295 	enum can_state state, old_state = priv->can.state;
296 
297 	if (canrflg & MSCAN_CSCIF && old_state <= CAN_STATE_BUS_OFF) {
298 		state = state_map[max(MSCAN_STATE_RX(canrflg),
299 				      MSCAN_STATE_TX(canrflg))];
300 		priv->can.state = state;
301 	}
302 	return old_state;
303 }
304 
305 static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
306 {
307 	struct mscan_priv *priv = netdev_priv(dev);
308 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
309 	u32 can_id;
310 	int i;
311 
312 	can_id = in_be16(&regs->rx.idr1_0);
313 	if (can_id & (1 << 3)) {
314 		frame->can_id = CAN_EFF_FLAG;
315 		can_id = ((can_id << 16) | in_be16(&regs->rx.idr3_2));
316 		can_id = ((can_id & 0xffe00000) |
317 			  ((can_id & 0x7ffff) << 2)) >> 2;
318 	} else {
319 		can_id >>= 4;
320 		frame->can_id = 0;
321 	}
322 
323 	frame->can_id |= can_id >> 1;
324 	if (can_id & 1)
325 		frame->can_id |= CAN_RTR_FLAG;
326 
327 	frame->can_dlc = get_can_dlc(in_8(&regs->rx.dlr) & 0xf);
328 
329 	if (!(frame->can_id & CAN_RTR_FLAG)) {
330 		void __iomem *data = &regs->rx.dsr1_0;
331 		u16 *payload = (u16 *)frame->data;
332 
333 		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
334 			*payload++ = in_be16(data);
335 			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
336 		}
337 	}
338 
339 	out_8(&regs->canrflg, MSCAN_RXF);
340 }
341 
342 static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
343 				u8 canrflg)
344 {
345 	struct mscan_priv *priv = netdev_priv(dev);
346 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
347 	struct net_device_stats *stats = &dev->stats;
348 	enum can_state old_state;
349 
350 	dev_dbg(dev->dev.parent, "error interrupt (canrflg=%#x)\n", canrflg);
351 	frame->can_id = CAN_ERR_FLAG;
352 
353 	if (canrflg & MSCAN_OVRIF) {
354 		frame->can_id |= CAN_ERR_CRTL;
355 		frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
356 		stats->rx_over_errors++;
357 		stats->rx_errors++;
358 	} else {
359 		frame->data[1] = 0;
360 	}
361 
362 	old_state = check_set_state(dev, canrflg);
363 	/* State changed */
364 	if (old_state != priv->can.state) {
365 		switch (priv->can.state) {
366 		case CAN_STATE_ERROR_WARNING:
367 			frame->can_id |= CAN_ERR_CRTL;
368 			priv->can.can_stats.error_warning++;
369 			if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
370 			    (canrflg & MSCAN_RSTAT_MSK))
371 				frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
372 			if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
373 			    (canrflg & MSCAN_TSTAT_MSK))
374 				frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
375 			break;
376 		case CAN_STATE_ERROR_PASSIVE:
377 			frame->can_id |= CAN_ERR_CRTL;
378 			priv->can.can_stats.error_passive++;
379 			frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
380 			break;
381 		case CAN_STATE_BUS_OFF:
382 			frame->can_id |= CAN_ERR_BUSOFF;
383 			/*
384 			 * The MSCAN on the MPC5200 does recover from bus-off
385 			 * automatically. To avoid that we stop the chip doing
386 			 * a light-weight stop (we are in irq-context).
387 			 */
388 			if (priv->type != MSCAN_TYPE_MPC5121) {
389 				out_8(&regs->cantier, 0);
390 				out_8(&regs->canrier, 0);
391 				setbits8(&regs->canctl0,
392 					 MSCAN_SLPRQ | MSCAN_INITRQ);
393 			}
394 			can_bus_off(dev);
395 			break;
396 		default:
397 			break;
398 		}
399 	}
400 	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
401 	frame->can_dlc = CAN_ERR_DLC;
402 	out_8(&regs->canrflg, MSCAN_ERR_IF);
403 }
404 
405 static int mscan_rx_poll(struct napi_struct *napi, int quota)
406 {
407 	struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
408 	struct net_device *dev = napi->dev;
409 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
410 	struct net_device_stats *stats = &dev->stats;
411 	int npackets = 0;
412 	int ret = 1;
413 	struct sk_buff *skb;
414 	struct can_frame *frame;
415 	u8 canrflg;
416 
417 	while (npackets < quota) {
418 		canrflg = in_8(&regs->canrflg);
419 		if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF)))
420 			break;
421 
422 		skb = alloc_can_skb(dev, &frame);
423 		if (!skb) {
424 			if (printk_ratelimit())
425 				dev_notice(dev->dev.parent, "packet dropped\n");
426 			stats->rx_dropped++;
427 			out_8(&regs->canrflg, canrflg);
428 			continue;
429 		}
430 
431 		if (canrflg & MSCAN_RXF)
432 			mscan_get_rx_frame(dev, frame);
433 		else if (canrflg & MSCAN_ERR_IF)
434 			mscan_get_err_frame(dev, frame, canrflg);
435 
436 		stats->rx_packets++;
437 		stats->rx_bytes += frame->can_dlc;
438 		npackets++;
439 		netif_receive_skb(skb);
440 	}
441 
442 	if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
443 		napi_complete(&priv->napi);
444 		clear_bit(F_RX_PROGRESS, &priv->flags);
445 		if (priv->can.state < CAN_STATE_BUS_OFF)
446 			out_8(&regs->canrier, priv->shadow_canrier);
447 		ret = 0;
448 	}
449 	return ret;
450 }
451 
452 static irqreturn_t mscan_isr(int irq, void *dev_id)
453 {
454 	struct net_device *dev = (struct net_device *)dev_id;
455 	struct mscan_priv *priv = netdev_priv(dev);
456 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
457 	struct net_device_stats *stats = &dev->stats;
458 	u8 cantier, cantflg, canrflg;
459 	irqreturn_t ret = IRQ_NONE;
460 
461 	cantier = in_8(&regs->cantier) & MSCAN_TXE;
462 	cantflg = in_8(&regs->cantflg) & cantier;
463 
464 	if (cantier && cantflg) {
465 		struct list_head *tmp, *pos;
466 
467 		list_for_each_safe(pos, tmp, &priv->tx_head) {
468 			struct tx_queue_entry *entry =
469 			    list_entry(pos, struct tx_queue_entry, list);
470 			u8 mask = entry->mask;
471 
472 			if (!(cantflg & mask))
473 				continue;
474 
475 			out_8(&regs->cantbsel, mask);
476 			stats->tx_bytes += in_8(&regs->tx.dlr);
477 			stats->tx_packets++;
478 			can_get_echo_skb(dev, entry->id);
479 			priv->tx_active &= ~mask;
480 			list_del(pos);
481 		}
482 
483 		if (list_empty(&priv->tx_head)) {
484 			clear_bit(F_TX_WAIT_ALL, &priv->flags);
485 			clear_bit(F_TX_PROGRESS, &priv->flags);
486 			priv->cur_pri = 0;
487 		} else {
488 			dev->trans_start = jiffies;
489 		}
490 
491 		if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
492 			netif_wake_queue(dev);
493 
494 		out_8(&regs->cantier, priv->tx_active);
495 		ret = IRQ_HANDLED;
496 	}
497 
498 	canrflg = in_8(&regs->canrflg);
499 	if ((canrflg & ~MSCAN_STAT_MSK) &&
500 	    !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
501 		if (canrflg & ~MSCAN_STAT_MSK) {
502 			priv->shadow_canrier = in_8(&regs->canrier);
503 			out_8(&regs->canrier, 0);
504 			napi_schedule(&priv->napi);
505 			ret = IRQ_HANDLED;
506 		} else {
507 			clear_bit(F_RX_PROGRESS, &priv->flags);
508 		}
509 	}
510 	return ret;
511 }
512 
513 static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
514 {
515 	struct mscan_priv *priv = netdev_priv(dev);
516 	int ret = 0;
517 
518 	if (!priv->open_time)
519 		return -EINVAL;
520 
521 	switch (mode) {
522 	case CAN_MODE_START:
523 		ret = mscan_restart(dev);
524 		if (ret)
525 			break;
526 		if (netif_queue_stopped(dev))
527 			netif_wake_queue(dev);
528 		break;
529 
530 	default:
531 		ret = -EOPNOTSUPP;
532 		break;
533 	}
534 	return ret;
535 }
536 
537 static int mscan_do_set_bittiming(struct net_device *dev)
538 {
539 	struct mscan_priv *priv = netdev_priv(dev);
540 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
541 	struct can_bittiming *bt = &priv->can.bittiming;
542 	u8 btr0, btr1;
543 
544 	btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
545 	btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
546 		BTR1_SET_TSEG2(bt->phase_seg2) |
547 		BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));
548 
549 	dev_info(dev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
550 		btr0, btr1);
551 
552 	out_8(&regs->canbtr0, btr0);
553 	out_8(&regs->canbtr1, btr1);
554 
555 	return 0;
556 }
557 
558 static int mscan_open(struct net_device *dev)
559 {
560 	int ret;
561 	struct mscan_priv *priv = netdev_priv(dev);
562 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
563 
564 	/* common open */
565 	ret = open_candev(dev);
566 	if (ret)
567 		return ret;
568 
569 	napi_enable(&priv->napi);
570 
571 	ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
572 	if (ret < 0) {
573 		dev_err(dev->dev.parent, "failed to attach interrupt\n");
574 		goto exit_napi_disable;
575 	}
576 
577 	priv->open_time = jiffies;
578 
579 	clrbits8(&regs->canctl1, MSCAN_LISTEN);
580 
581 	ret = mscan_start(dev);
582 	if (ret)
583 		goto exit_free_irq;
584 
585 	netif_start_queue(dev);
586 
587 	return 0;
588 
589 exit_free_irq:
590 	priv->open_time = 0;
591 	free_irq(dev->irq, dev);
592 exit_napi_disable:
593 	napi_disable(&priv->napi);
594 	close_candev(dev);
595 	return ret;
596 }
597 
598 static int mscan_close(struct net_device *dev)
599 {
600 	struct mscan_priv *priv = netdev_priv(dev);
601 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
602 
603 	netif_stop_queue(dev);
604 	napi_disable(&priv->napi);
605 
606 	out_8(&regs->cantier, 0);
607 	out_8(&regs->canrier, 0);
608 	mscan_set_mode(dev, MSCAN_INIT_MODE);
609 	close_candev(dev);
610 	free_irq(dev->irq, dev);
611 	priv->open_time = 0;
612 
613 	return 0;
614 }
615 
616 static const struct net_device_ops mscan_netdev_ops = {
617        .ndo_open               = mscan_open,
618        .ndo_stop               = mscan_close,
619        .ndo_start_xmit         = mscan_start_xmit,
620 };
621 
622 int register_mscandev(struct net_device *dev, int mscan_clksrc)
623 {
624 	struct mscan_priv *priv = netdev_priv(dev);
625 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
626 	u8 ctl1;
627 
628 	ctl1 = in_8(&regs->canctl1);
629 	if (mscan_clksrc)
630 		ctl1 |= MSCAN_CLKSRC;
631 	else
632 		ctl1 &= ~MSCAN_CLKSRC;
633 
634 	if (priv->type == MSCAN_TYPE_MPC5121)
635 		ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */
636 
637 	ctl1 |= MSCAN_CANE;
638 	out_8(&regs->canctl1, ctl1);
639 	udelay(100);
640 
641 	/* acceptance mask/acceptance code (accept everything) */
642 	out_be16(&regs->canidar1_0, 0);
643 	out_be16(&regs->canidar3_2, 0);
644 	out_be16(&regs->canidar5_4, 0);
645 	out_be16(&regs->canidar7_6, 0);
646 
647 	out_be16(&regs->canidmr1_0, 0xffff);
648 	out_be16(&regs->canidmr3_2, 0xffff);
649 	out_be16(&regs->canidmr5_4, 0xffff);
650 	out_be16(&regs->canidmr7_6, 0xffff);
651 	/* Two 32 bit Acceptance Filters */
652 	out_8(&regs->canidac, MSCAN_AF_32BIT);
653 
654 	mscan_set_mode(dev, MSCAN_INIT_MODE);
655 
656 	return register_candev(dev);
657 }
658 
659 void unregister_mscandev(struct net_device *dev)
660 {
661 	struct mscan_priv *priv = netdev_priv(dev);
662 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
663 	mscan_set_mode(dev, MSCAN_INIT_MODE);
664 	clrbits8(&regs->canctl1, MSCAN_CANE);
665 	unregister_candev(dev);
666 }
667 
668 struct net_device *alloc_mscandev(void)
669 {
670 	struct net_device *dev;
671 	struct mscan_priv *priv;
672 	int i;
673 
674 	dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
675 	if (!dev)
676 		return NULL;
677 	priv = netdev_priv(dev);
678 
679 	dev->netdev_ops = &mscan_netdev_ops;
680 
681 	dev->flags |= IFF_ECHO;	/* we support local echo */
682 
683 	netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);
684 
685 	priv->can.bittiming_const = &mscan_bittiming_const;
686 	priv->can.do_set_bittiming = mscan_do_set_bittiming;
687 	priv->can.do_set_mode = mscan_do_set_mode;
688 	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
689 
690 	for (i = 0; i < TX_QUEUE_SIZE; i++) {
691 		priv->tx_queue[i].id = i;
692 		priv->tx_queue[i].mask = 1 << i;
693 	}
694 
695 	return dev;
696 }
697 
698 MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
699 MODULE_LICENSE("GPL v2");
700 MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");
701