xref: /openbmc/linux/drivers/net/can/mscan/mscan.c (revision b34081f1)
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 const 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 __iomem *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 				netdev_dbg(dev,
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 __iomem *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 __iomem *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 __iomem *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 		netdev_err(dev, "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 between 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 		for (i = 0; i < frame->can_dlc / 2; i++) {
265 			out_be16(data, *payload++);
266 			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
267 		}
268 		/* write remaining byte if necessary */
269 		if (frame->can_dlc & 1)
270 			out_8(data, frame->data[frame->can_dlc - 1]);
271 	}
272 
273 	out_8(&regs->tx.dlr, frame->can_dlc);
274 	out_8(&regs->tx.tbpr, priv->cur_pri);
275 
276 	/* Start transmission. */
277 	out_8(&regs->cantflg, 1 << buf_id);
278 
279 	if (!test_bit(F_TX_PROGRESS, &priv->flags))
280 		dev->trans_start = jiffies;
281 
282 	list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);
283 
284 	can_put_echo_skb(skb, dev, buf_id);
285 
286 	/* Enable interrupt. */
287 	priv->tx_active |= 1 << buf_id;
288 	out_8(&regs->cantier, priv->tx_active);
289 
290 	return NETDEV_TX_OK;
291 }
292 
293 /* This function returns the old state to see where we came from */
294 static enum can_state check_set_state(struct net_device *dev, u8 canrflg)
295 {
296 	struct mscan_priv *priv = netdev_priv(dev);
297 	enum can_state state, old_state = priv->can.state;
298 
299 	if (canrflg & MSCAN_CSCIF && old_state <= CAN_STATE_BUS_OFF) {
300 		state = state_map[max(MSCAN_STATE_RX(canrflg),
301 				      MSCAN_STATE_TX(canrflg))];
302 		priv->can.state = state;
303 	}
304 	return old_state;
305 }
306 
307 static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
308 {
309 	struct mscan_priv *priv = netdev_priv(dev);
310 	struct mscan_regs __iomem *regs = priv->reg_base;
311 	u32 can_id;
312 	int i;
313 
314 	can_id = in_be16(&regs->rx.idr1_0);
315 	if (can_id & (1 << 3)) {
316 		frame->can_id = CAN_EFF_FLAG;
317 		can_id = ((can_id << 16) | in_be16(&regs->rx.idr3_2));
318 		can_id = ((can_id & 0xffe00000) |
319 			  ((can_id & 0x7ffff) << 2)) >> 2;
320 	} else {
321 		can_id >>= 4;
322 		frame->can_id = 0;
323 	}
324 
325 	frame->can_id |= can_id >> 1;
326 	if (can_id & 1)
327 		frame->can_id |= CAN_RTR_FLAG;
328 
329 	frame->can_dlc = get_can_dlc(in_8(&regs->rx.dlr) & 0xf);
330 
331 	if (!(frame->can_id & CAN_RTR_FLAG)) {
332 		void __iomem *data = &regs->rx.dsr1_0;
333 		u16 *payload = (u16 *)frame->data;
334 
335 		for (i = 0; i < frame->can_dlc / 2; i++) {
336 			*payload++ = in_be16(data);
337 			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
338 		}
339 		/* read remaining byte if necessary */
340 		if (frame->can_dlc & 1)
341 			frame->data[frame->can_dlc - 1] = in_8(data);
342 	}
343 
344 	out_8(&regs->canrflg, MSCAN_RXF);
345 }
346 
347 static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
348 				u8 canrflg)
349 {
350 	struct mscan_priv *priv = netdev_priv(dev);
351 	struct mscan_regs __iomem *regs = priv->reg_base;
352 	struct net_device_stats *stats = &dev->stats;
353 	enum can_state old_state;
354 
355 	netdev_dbg(dev, "error interrupt (canrflg=%#x)\n", canrflg);
356 	frame->can_id = CAN_ERR_FLAG;
357 
358 	if (canrflg & MSCAN_OVRIF) {
359 		frame->can_id |= CAN_ERR_CRTL;
360 		frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
361 		stats->rx_over_errors++;
362 		stats->rx_errors++;
363 	} else {
364 		frame->data[1] = 0;
365 	}
366 
367 	old_state = check_set_state(dev, canrflg);
368 	/* State changed */
369 	if (old_state != priv->can.state) {
370 		switch (priv->can.state) {
371 		case CAN_STATE_ERROR_WARNING:
372 			frame->can_id |= CAN_ERR_CRTL;
373 			priv->can.can_stats.error_warning++;
374 			if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
375 			    (canrflg & MSCAN_RSTAT_MSK))
376 				frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
377 			if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
378 			    (canrflg & MSCAN_TSTAT_MSK))
379 				frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
380 			break;
381 		case CAN_STATE_ERROR_PASSIVE:
382 			frame->can_id |= CAN_ERR_CRTL;
383 			priv->can.can_stats.error_passive++;
384 			frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
385 			break;
386 		case CAN_STATE_BUS_OFF:
387 			frame->can_id |= CAN_ERR_BUSOFF;
388 			/*
389 			 * The MSCAN on the MPC5200 does recover from bus-off
390 			 * automatically. To avoid that we stop the chip doing
391 			 * a light-weight stop (we are in irq-context).
392 			 */
393 			if (priv->type != MSCAN_TYPE_MPC5121) {
394 				out_8(&regs->cantier, 0);
395 				out_8(&regs->canrier, 0);
396 				setbits8(&regs->canctl0,
397 					 MSCAN_SLPRQ | MSCAN_INITRQ);
398 			}
399 			can_bus_off(dev);
400 			break;
401 		default:
402 			break;
403 		}
404 	}
405 	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
406 	frame->can_dlc = CAN_ERR_DLC;
407 	out_8(&regs->canrflg, MSCAN_ERR_IF);
408 }
409 
410 static int mscan_rx_poll(struct napi_struct *napi, int quota)
411 {
412 	struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
413 	struct net_device *dev = napi->dev;
414 	struct mscan_regs __iomem *regs = priv->reg_base;
415 	struct net_device_stats *stats = &dev->stats;
416 	int npackets = 0;
417 	int ret = 1;
418 	struct sk_buff *skb;
419 	struct can_frame *frame;
420 	u8 canrflg;
421 
422 	while (npackets < quota) {
423 		canrflg = in_8(&regs->canrflg);
424 		if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF)))
425 			break;
426 
427 		skb = alloc_can_skb(dev, &frame);
428 		if (!skb) {
429 			if (printk_ratelimit())
430 				netdev_notice(dev, "packet dropped\n");
431 			stats->rx_dropped++;
432 			out_8(&regs->canrflg, canrflg);
433 			continue;
434 		}
435 
436 		if (canrflg & MSCAN_RXF)
437 			mscan_get_rx_frame(dev, frame);
438 		else if (canrflg & MSCAN_ERR_IF)
439 			mscan_get_err_frame(dev, frame, canrflg);
440 
441 		stats->rx_packets++;
442 		stats->rx_bytes += frame->can_dlc;
443 		npackets++;
444 		netif_receive_skb(skb);
445 	}
446 
447 	if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
448 		napi_complete(&priv->napi);
449 		clear_bit(F_RX_PROGRESS, &priv->flags);
450 		if (priv->can.state < CAN_STATE_BUS_OFF)
451 			out_8(&regs->canrier, priv->shadow_canrier);
452 		ret = 0;
453 	}
454 	return ret;
455 }
456 
457 static irqreturn_t mscan_isr(int irq, void *dev_id)
458 {
459 	struct net_device *dev = (struct net_device *)dev_id;
460 	struct mscan_priv *priv = netdev_priv(dev);
461 	struct mscan_regs __iomem *regs = priv->reg_base;
462 	struct net_device_stats *stats = &dev->stats;
463 	u8 cantier, cantflg, canrflg;
464 	irqreturn_t ret = IRQ_NONE;
465 
466 	cantier = in_8(&regs->cantier) & MSCAN_TXE;
467 	cantflg = in_8(&regs->cantflg) & cantier;
468 
469 	if (cantier && cantflg) {
470 		struct list_head *tmp, *pos;
471 
472 		list_for_each_safe(pos, tmp, &priv->tx_head) {
473 			struct tx_queue_entry *entry =
474 			    list_entry(pos, struct tx_queue_entry, list);
475 			u8 mask = entry->mask;
476 
477 			if (!(cantflg & mask))
478 				continue;
479 
480 			out_8(&regs->cantbsel, mask);
481 			stats->tx_bytes += in_8(&regs->tx.dlr);
482 			stats->tx_packets++;
483 			can_get_echo_skb(dev, entry->id);
484 			priv->tx_active &= ~mask;
485 			list_del(pos);
486 		}
487 
488 		if (list_empty(&priv->tx_head)) {
489 			clear_bit(F_TX_WAIT_ALL, &priv->flags);
490 			clear_bit(F_TX_PROGRESS, &priv->flags);
491 			priv->cur_pri = 0;
492 		} else {
493 			dev->trans_start = jiffies;
494 		}
495 
496 		if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
497 			netif_wake_queue(dev);
498 
499 		out_8(&regs->cantier, priv->tx_active);
500 		ret = IRQ_HANDLED;
501 	}
502 
503 	canrflg = in_8(&regs->canrflg);
504 	if ((canrflg & ~MSCAN_STAT_MSK) &&
505 	    !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
506 		if (canrflg & ~MSCAN_STAT_MSK) {
507 			priv->shadow_canrier = in_8(&regs->canrier);
508 			out_8(&regs->canrier, 0);
509 			napi_schedule(&priv->napi);
510 			ret = IRQ_HANDLED;
511 		} else {
512 			clear_bit(F_RX_PROGRESS, &priv->flags);
513 		}
514 	}
515 	return ret;
516 }
517 
518 static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
519 {
520 	int ret = 0;
521 
522 	switch (mode) {
523 	case CAN_MODE_START:
524 		ret = mscan_restart(dev);
525 		if (ret)
526 			break;
527 		if (netif_queue_stopped(dev))
528 			netif_wake_queue(dev);
529 		break;
530 
531 	default:
532 		ret = -EOPNOTSUPP;
533 		break;
534 	}
535 	return ret;
536 }
537 
538 static int mscan_do_set_bittiming(struct net_device *dev)
539 {
540 	struct mscan_priv *priv = netdev_priv(dev);
541 	struct mscan_regs __iomem *regs = priv->reg_base;
542 	struct can_bittiming *bt = &priv->can.bittiming;
543 	u8 btr0, btr1;
544 
545 	btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
546 	btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
547 		BTR1_SET_TSEG2(bt->phase_seg2) |
548 		BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));
549 
550 	netdev_info(dev, "setting BTR0=0x%02x BTR1=0x%02x\n", 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_get_berr_counter(const struct net_device *dev,
559 				  struct can_berr_counter *bec)
560 {
561 	struct mscan_priv *priv = netdev_priv(dev);
562 	struct mscan_regs __iomem *regs = priv->reg_base;
563 
564 	bec->txerr = in_8(&regs->cantxerr);
565 	bec->rxerr = in_8(&regs->canrxerr);
566 
567 	return 0;
568 }
569 
570 static int mscan_open(struct net_device *dev)
571 {
572 	int ret;
573 	struct mscan_priv *priv = netdev_priv(dev);
574 	struct mscan_regs __iomem *regs = priv->reg_base;
575 
576 	if (priv->clk_ipg) {
577 		ret = clk_prepare_enable(priv->clk_ipg);
578 		if (ret)
579 			goto exit_retcode;
580 	}
581 	if (priv->clk_can) {
582 		ret = clk_prepare_enable(priv->clk_can);
583 		if (ret)
584 			goto exit_dis_ipg_clock;
585 	}
586 
587 	/* common open */
588 	ret = open_candev(dev);
589 	if (ret)
590 		goto exit_dis_can_clock;
591 
592 	napi_enable(&priv->napi);
593 
594 	ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
595 	if (ret < 0) {
596 		netdev_err(dev, "failed to attach interrupt\n");
597 		goto exit_napi_disable;
598 	}
599 
600 	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
601 		setbits8(&regs->canctl1, MSCAN_LISTEN);
602 	else
603 		clrbits8(&regs->canctl1, MSCAN_LISTEN);
604 
605 	ret = mscan_start(dev);
606 	if (ret)
607 		goto exit_free_irq;
608 
609 	netif_start_queue(dev);
610 
611 	return 0;
612 
613 exit_free_irq:
614 	free_irq(dev->irq, dev);
615 exit_napi_disable:
616 	napi_disable(&priv->napi);
617 	close_candev(dev);
618 exit_dis_can_clock:
619 	if (priv->clk_can)
620 		clk_disable_unprepare(priv->clk_can);
621 exit_dis_ipg_clock:
622 	if (priv->clk_ipg)
623 		clk_disable_unprepare(priv->clk_ipg);
624 exit_retcode:
625 	return ret;
626 }
627 
628 static int mscan_close(struct net_device *dev)
629 {
630 	struct mscan_priv *priv = netdev_priv(dev);
631 	struct mscan_regs __iomem *regs = priv->reg_base;
632 
633 	netif_stop_queue(dev);
634 	napi_disable(&priv->napi);
635 
636 	out_8(&regs->cantier, 0);
637 	out_8(&regs->canrier, 0);
638 	mscan_set_mode(dev, MSCAN_INIT_MODE);
639 	close_candev(dev);
640 	free_irq(dev->irq, dev);
641 
642 	if (priv->clk_can)
643 		clk_disable_unprepare(priv->clk_can);
644 	if (priv->clk_ipg)
645 		clk_disable_unprepare(priv->clk_ipg);
646 
647 	return 0;
648 }
649 
650 static const struct net_device_ops mscan_netdev_ops = {
651        .ndo_open               = mscan_open,
652        .ndo_stop               = mscan_close,
653        .ndo_start_xmit         = mscan_start_xmit,
654 };
655 
656 int register_mscandev(struct net_device *dev, int mscan_clksrc)
657 {
658 	struct mscan_priv *priv = netdev_priv(dev);
659 	struct mscan_regs __iomem *regs = priv->reg_base;
660 	u8 ctl1;
661 
662 	ctl1 = in_8(&regs->canctl1);
663 	if (mscan_clksrc)
664 		ctl1 |= MSCAN_CLKSRC;
665 	else
666 		ctl1 &= ~MSCAN_CLKSRC;
667 
668 	if (priv->type == MSCAN_TYPE_MPC5121) {
669 		priv->can.do_get_berr_counter = mscan_get_berr_counter;
670 		ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */
671 	}
672 
673 	ctl1 |= MSCAN_CANE;
674 	out_8(&regs->canctl1, ctl1);
675 	udelay(100);
676 
677 	/* acceptance mask/acceptance code (accept everything) */
678 	out_be16(&regs->canidar1_0, 0);
679 	out_be16(&regs->canidar3_2, 0);
680 	out_be16(&regs->canidar5_4, 0);
681 	out_be16(&regs->canidar7_6, 0);
682 
683 	out_be16(&regs->canidmr1_0, 0xffff);
684 	out_be16(&regs->canidmr3_2, 0xffff);
685 	out_be16(&regs->canidmr5_4, 0xffff);
686 	out_be16(&regs->canidmr7_6, 0xffff);
687 	/* Two 32 bit Acceptance Filters */
688 	out_8(&regs->canidac, MSCAN_AF_32BIT);
689 
690 	mscan_set_mode(dev, MSCAN_INIT_MODE);
691 
692 	return register_candev(dev);
693 }
694 
695 void unregister_mscandev(struct net_device *dev)
696 {
697 	struct mscan_priv *priv = netdev_priv(dev);
698 	struct mscan_regs __iomem *regs = priv->reg_base;
699 	mscan_set_mode(dev, MSCAN_INIT_MODE);
700 	clrbits8(&regs->canctl1, MSCAN_CANE);
701 	unregister_candev(dev);
702 }
703 
704 struct net_device *alloc_mscandev(void)
705 {
706 	struct net_device *dev;
707 	struct mscan_priv *priv;
708 	int i;
709 
710 	dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
711 	if (!dev)
712 		return NULL;
713 	priv = netdev_priv(dev);
714 
715 	dev->netdev_ops = &mscan_netdev_ops;
716 
717 	dev->flags |= IFF_ECHO;	/* we support local echo */
718 
719 	netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);
720 
721 	priv->can.bittiming_const = &mscan_bittiming_const;
722 	priv->can.do_set_bittiming = mscan_do_set_bittiming;
723 	priv->can.do_set_mode = mscan_do_set_mode;
724 	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
725 		CAN_CTRLMODE_LISTENONLY;
726 
727 	for (i = 0; i < TX_QUEUE_SIZE; i++) {
728 		priv->tx_queue[i].id = i;
729 		priv->tx_queue[i].mask = 1 << i;
730 	}
731 
732 	return dev;
733 }
734 
735 MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
736 MODULE_LICENSE("GPL v2");
737 MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");
738