1/*
2 * sja1000.c -  Philips SJA1000 network device driver
3 *
4 * Copyright (c) 2003 Matthias Brukner, Trajet Gmbh, Rebenring 33,
5 * 38106 Braunschweig, GERMANY
6 *
7 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of Volkswagen nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * Alternatively, provided that this notice is retained in full, this
23 * software may be distributed under the terms of the GNU General
24 * Public License ("GPL") version 2, in which case the provisions of the
25 * GPL apply INSTEAD OF those given above.
26 *
27 * The provided data structures and external interfaces from this code
28 * are not restricted to be used by modules with a GPL compatible license.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
33 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
34 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
36 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
40 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
41 * DAMAGE.
42 *
43 */
44
45#include <linux/module.h>
46#include <linux/init.h>
47#include <linux/kernel.h>
48#include <linux/sched.h>
49#include <linux/types.h>
50#include <linux/fcntl.h>
51#include <linux/interrupt.h>
52#include <linux/ptrace.h>
53#include <linux/string.h>
54#include <linux/errno.h>
55#include <linux/netdevice.h>
56#include <linux/if_arp.h>
57#include <linux/if_ether.h>
58#include <linux/skbuff.h>
59#include <linux/delay.h>
60
61#include <linux/can/dev.h>
62#include <linux/can/error.h>
63
64#include "sja1000.h"
65
66#define DRV_NAME "sja1000"
67
68MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
69MODULE_LICENSE("Dual BSD/GPL");
70MODULE_DESCRIPTION(DRV_NAME "CAN netdevice driver");
71
72static struct can_bittiming_const sja1000_bittiming_const = {
73	.name = DRV_NAME,
74	.tseg1_min = 1,
75	.tseg1_max = 16,
76	.tseg2_min = 1,
77	.tseg2_max = 8,
78	.sjw_max = 4,
79	.brp_min = 1,
80	.brp_max = 64,
81	.brp_inc = 1,
82};
83
84static void sja1000_write_cmdreg(struct sja1000_priv *priv, u8 val)
85{
86	unsigned long flags;
87
88	/*
89	 * The command register needs some locking and time to settle
90	 * the write_reg() operation - especially on SMP systems.
91	 */
92	spin_lock_irqsave(&priv->cmdreg_lock, flags);
93	priv->write_reg(priv, REG_CMR, val);
94	priv->read_reg(priv, REG_SR);
95	spin_unlock_irqrestore(&priv->cmdreg_lock, flags);
96}
97
98static int sja1000_is_absent(struct sja1000_priv *priv)
99{
100	return (priv->read_reg(priv, REG_MOD) == 0xFF);
101}
102
103static int sja1000_probe_chip(struct net_device *dev)
104{
105	struct sja1000_priv *priv = netdev_priv(dev);
106
107	if (priv->reg_base && sja1000_is_absent(priv)) {
108		printk(KERN_INFO "%s: probing @0x%lX failed\n",
109		       DRV_NAME, dev->base_addr);
110		return 0;
111	}
112	return -1;
113}
114
115static void set_reset_mode(struct net_device *dev)
116{
117	struct sja1000_priv *priv = netdev_priv(dev);
118	unsigned char status = priv->read_reg(priv, REG_MOD);
119	int i;
120
121	/* disable interrupts */
122	priv->write_reg(priv, REG_IER, IRQ_OFF);
123
124	for (i = 0; i < 100; i++) {
125		/* check reset bit */
126		if (status & MOD_RM) {
127			priv->can.state = CAN_STATE_STOPPED;
128			return;
129		}
130
131		priv->write_reg(priv, REG_MOD, MOD_RM);	/* reset chip */
132		udelay(10);
133		status = priv->read_reg(priv, REG_MOD);
134	}
135
136	netdev_err(dev, "setting SJA1000 into reset mode failed!\n");
137}
138
139static void set_normal_mode(struct net_device *dev)
140{
141	struct sja1000_priv *priv = netdev_priv(dev);
142	unsigned char status = priv->read_reg(priv, REG_MOD);
143	int i;
144
145	for (i = 0; i < 100; i++) {
146		/* check reset bit */
147		if ((status & MOD_RM) == 0) {
148			priv->can.state = CAN_STATE_ERROR_ACTIVE;
149			/* enable interrupts */
150			if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
151				priv->write_reg(priv, REG_IER, IRQ_ALL);
152			else
153				priv->write_reg(priv, REG_IER,
154						IRQ_ALL & ~IRQ_BEI);
155			return;
156		}
157
158		/* set chip to normal mode */
159		priv->write_reg(priv, REG_MOD, 0x00);
160		udelay(10);
161		status = priv->read_reg(priv, REG_MOD);
162	}
163
164	netdev_err(dev, "setting SJA1000 into normal mode failed!\n");
165}
166
167static void sja1000_start(struct net_device *dev)
168{
169	struct sja1000_priv *priv = netdev_priv(dev);
170
171	/* leave reset mode */
172	if (priv->can.state != CAN_STATE_STOPPED)
173		set_reset_mode(dev);
174
175	/* Clear error counters and error code capture */
176	priv->write_reg(priv, REG_TXERR, 0x0);
177	priv->write_reg(priv, REG_RXERR, 0x0);
178	priv->read_reg(priv, REG_ECC);
179
180	/* leave reset mode */
181	set_normal_mode(dev);
182}
183
184static int sja1000_set_mode(struct net_device *dev, enum can_mode mode)
185{
186	struct sja1000_priv *priv = netdev_priv(dev);
187
188	if (!priv->open_time)
189		return -EINVAL;
190
191	switch (mode) {
192	case CAN_MODE_START:
193		sja1000_start(dev);
194		if (netif_queue_stopped(dev))
195			netif_wake_queue(dev);
196		break;
197
198	default:
199		return -EOPNOTSUPP;
200	}
201
202	return 0;
203}
204
205static int sja1000_set_bittiming(struct net_device *dev)
206{
207	struct sja1000_priv *priv = netdev_priv(dev);
208	struct can_bittiming *bt = &priv->can.bittiming;
209	u8 btr0, btr1;
210
211	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
212	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
213		(((bt->phase_seg2 - 1) & 0x7) << 4);
214	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
215		btr1 |= 0x80;
216
217	netdev_info(dev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
218
219	priv->write_reg(priv, REG_BTR0, btr0);
220	priv->write_reg(priv, REG_BTR1, btr1);
221
222	return 0;
223}
224
225static int sja1000_get_berr_counter(const struct net_device *dev,
226				    struct can_berr_counter *bec)
227{
228	struct sja1000_priv *priv = netdev_priv(dev);
229
230	bec->txerr = priv->read_reg(priv, REG_TXERR);
231	bec->rxerr = priv->read_reg(priv, REG_RXERR);
232
233	return 0;
234}
235
236/*
237 * initialize SJA1000 chip:
238 *   - reset chip
239 *   - set output mode
240 *   - set baudrate
241 *   - enable interrupts
242 *   - start operating mode
243 */
244static void chipset_init(struct net_device *dev)
245{
246	struct sja1000_priv *priv = netdev_priv(dev);
247
248	/* set clock divider and output control register */
249	priv->write_reg(priv, REG_CDR, priv->cdr | CDR_PELICAN);
250
251	/* set acceptance filter (accept all) */
252	priv->write_reg(priv, REG_ACCC0, 0x00);
253	priv->write_reg(priv, REG_ACCC1, 0x00);
254	priv->write_reg(priv, REG_ACCC2, 0x00);
255	priv->write_reg(priv, REG_ACCC3, 0x00);
256
257	priv->write_reg(priv, REG_ACCM0, 0xFF);
258	priv->write_reg(priv, REG_ACCM1, 0xFF);
259	priv->write_reg(priv, REG_ACCM2, 0xFF);
260	priv->write_reg(priv, REG_ACCM3, 0xFF);
261
262	priv->write_reg(priv, REG_OCR, priv->ocr | OCR_MODE_NORMAL);
263}
264
265/*
266 * transmit a CAN message
267 * message layout in the sk_buff should be like this:
268 * xx xx xx xx	 ff	 ll   00 11 22 33 44 55 66 77
269 * [  can-id ] [flags] [len] [can data (up to 8 bytes]
270 */
271static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
272					    struct net_device *dev)
273{
274	struct sja1000_priv *priv = netdev_priv(dev);
275	struct can_frame *cf = (struct can_frame *)skb->data;
276	uint8_t fi;
277	uint8_t dlc;
278	canid_t id;
279	uint8_t dreg;
280	int i;
281
282	if (can_dropped_invalid_skb(dev, skb))
283		return NETDEV_TX_OK;
284
285	netif_stop_queue(dev);
286
287	fi = dlc = cf->can_dlc;
288	id = cf->can_id;
289
290	if (id & CAN_RTR_FLAG)
291		fi |= FI_RTR;
292
293	if (id & CAN_EFF_FLAG) {
294		fi |= FI_FF;
295		dreg = EFF_BUF;
296		priv->write_reg(priv, REG_FI, fi);
297		priv->write_reg(priv, REG_ID1, (id & 0x1fe00000) >> (5 + 16));
298		priv->write_reg(priv, REG_ID2, (id & 0x001fe000) >> (5 + 8));
299		priv->write_reg(priv, REG_ID3, (id & 0x00001fe0) >> 5);
300		priv->write_reg(priv, REG_ID4, (id & 0x0000001f) << 3);
301	} else {
302		dreg = SFF_BUF;
303		priv->write_reg(priv, REG_FI, fi);
304		priv->write_reg(priv, REG_ID1, (id & 0x000007f8) >> 3);
305		priv->write_reg(priv, REG_ID2, (id & 0x00000007) << 5);
306	}
307
308	for (i = 0; i < dlc; i++)
309		priv->write_reg(priv, dreg++, cf->data[i]);
310
311	can_put_echo_skb(skb, dev, 0);
312
313	sja1000_write_cmdreg(priv, CMD_TR);
314
315	return NETDEV_TX_OK;
316}
317
318static void sja1000_rx(struct net_device *dev)
319{
320	struct sja1000_priv *priv = netdev_priv(dev);
321	struct net_device_stats *stats = &dev->stats;
322	struct can_frame *cf;
323	struct sk_buff *skb;
324	uint8_t fi;
325	uint8_t dreg;
326	canid_t id;
327	int i;
328
329	/* create zero'ed CAN frame buffer */
330	skb = alloc_can_skb(dev, &cf);
331	if (skb == NULL)
332		return;
333
334	fi = priv->read_reg(priv, REG_FI);
335
336	if (fi & FI_FF) {
337		/* extended frame format (EFF) */
338		dreg = EFF_BUF;
339		id = (priv->read_reg(priv, REG_ID1) << (5 + 16))
340		    | (priv->read_reg(priv, REG_ID2) << (5 + 8))
341		    | (priv->read_reg(priv, REG_ID3) << 5)
342		    | (priv->read_reg(priv, REG_ID4) >> 3);
343		id |= CAN_EFF_FLAG;
344	} else {
345		/* standard frame format (SFF) */
346		dreg = SFF_BUF;
347		id = (priv->read_reg(priv, REG_ID1) << 3)
348		    | (priv->read_reg(priv, REG_ID2) >> 5);
349	}
350
351	cf->can_dlc = get_can_dlc(fi & 0x0F);
352	if (fi & FI_RTR) {
353		id |= CAN_RTR_FLAG;
354	} else {
355		for (i = 0; i < cf->can_dlc; i++)
356			cf->data[i] = priv->read_reg(priv, dreg++);
357	}
358
359	cf->can_id = id;
360
361	/* release receive buffer */
362	sja1000_write_cmdreg(priv, CMD_RRB);
363
364	netif_rx(skb);
365
366	stats->rx_packets++;
367	stats->rx_bytes += cf->can_dlc;
368}
369
370static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
371{
372	struct sja1000_priv *priv = netdev_priv(dev);
373	struct net_device_stats *stats = &dev->stats;
374	struct can_frame *cf;
375	struct sk_buff *skb;
376	enum can_state state = priv->can.state;
377	uint8_t ecc, alc;
378
379	skb = alloc_can_err_skb(dev, &cf);
380	if (skb == NULL)
381		return -ENOMEM;
382
383	if (isrc & IRQ_DOI) {
384		/* data overrun interrupt */
385		netdev_dbg(dev, "data overrun interrupt\n");
386		cf->can_id |= CAN_ERR_CRTL;
387		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
388		stats->rx_over_errors++;
389		stats->rx_errors++;
390		sja1000_write_cmdreg(priv, CMD_CDO);	/* clear bit */
391	}
392
393	if (isrc & IRQ_EI) {
394		/* error warning interrupt */
395		netdev_dbg(dev, "error warning interrupt\n");
396
397		if (status & SR_BS) {
398			state = CAN_STATE_BUS_OFF;
399			cf->can_id |= CAN_ERR_BUSOFF;
400			can_bus_off(dev);
401		} else if (status & SR_ES) {
402			state = CAN_STATE_ERROR_WARNING;
403		} else
404			state = CAN_STATE_ERROR_ACTIVE;
405	}
406	if (isrc & IRQ_BEI) {
407		/* bus error interrupt */
408		priv->can.can_stats.bus_error++;
409		stats->rx_errors++;
410
411		ecc = priv->read_reg(priv, REG_ECC);
412
413		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
414
415		switch (ecc & ECC_MASK) {
416		case ECC_BIT:
417			cf->data[2] |= CAN_ERR_PROT_BIT;
418			break;
419		case ECC_FORM:
420			cf->data[2] |= CAN_ERR_PROT_FORM;
421			break;
422		case ECC_STUFF:
423			cf->data[2] |= CAN_ERR_PROT_STUFF;
424			break;
425		default:
426			cf->data[2] |= CAN_ERR_PROT_UNSPEC;
427			cf->data[3] = ecc & ECC_SEG;
428			break;
429		}
430		/* Error occurred during transmission? */
431		if ((ecc & ECC_DIR) == 0)
432			cf->data[2] |= CAN_ERR_PROT_TX;
433	}
434	if (isrc & IRQ_EPI) {
435		/* error passive interrupt */
436		netdev_dbg(dev, "error passive interrupt\n");
437		if (status & SR_ES)
438			state = CAN_STATE_ERROR_PASSIVE;
439		else
440			state = CAN_STATE_ERROR_ACTIVE;
441	}
442	if (isrc & IRQ_ALI) {
443		/* arbitration lost interrupt */
444		netdev_dbg(dev, "arbitration lost interrupt\n");
445		alc = priv->read_reg(priv, REG_ALC);
446		priv->can.can_stats.arbitration_lost++;
447		stats->tx_errors++;
448		cf->can_id |= CAN_ERR_LOSTARB;
449		cf->data[0] = alc & 0x1f;
450	}
451
452	if (state != priv->can.state && (state == CAN_STATE_ERROR_WARNING ||
453					 state == CAN_STATE_ERROR_PASSIVE)) {
454		uint8_t rxerr = priv->read_reg(priv, REG_RXERR);
455		uint8_t txerr = priv->read_reg(priv, REG_TXERR);
456		cf->can_id |= CAN_ERR_CRTL;
457		if (state == CAN_STATE_ERROR_WARNING) {
458			priv->can.can_stats.error_warning++;
459			cf->data[1] = (txerr > rxerr) ?
460				CAN_ERR_CRTL_TX_WARNING :
461				CAN_ERR_CRTL_RX_WARNING;
462		} else {
463			priv->can.can_stats.error_passive++;
464			cf->data[1] = (txerr > rxerr) ?
465				CAN_ERR_CRTL_TX_PASSIVE :
466				CAN_ERR_CRTL_RX_PASSIVE;
467		}
468		cf->data[6] = txerr;
469		cf->data[7] = rxerr;
470	}
471
472	priv->can.state = state;
473
474	netif_rx(skb);
475
476	stats->rx_packets++;
477	stats->rx_bytes += cf->can_dlc;
478
479	return 0;
480}
481
482irqreturn_t sja1000_interrupt(int irq, void *dev_id)
483{
484	struct net_device *dev = (struct net_device *)dev_id;
485	struct sja1000_priv *priv = netdev_priv(dev);
486	struct net_device_stats *stats = &dev->stats;
487	uint8_t isrc, status;
488	int n = 0;
489
490	/* Shared interrupts and IRQ off? */
491	if (priv->read_reg(priv, REG_IER) == IRQ_OFF)
492		return IRQ_NONE;
493
494	if (priv->pre_irq)
495		priv->pre_irq(priv);
496
497	while ((isrc = priv->read_reg(priv, REG_IR)) && (n < SJA1000_MAX_IRQ)) {
498		n++;
499		status = priv->read_reg(priv, REG_SR);
500		/* check for absent controller due to hw unplug */
501		if (status == 0xFF && sja1000_is_absent(priv))
502			return IRQ_NONE;
503
504		if (isrc & IRQ_WUI)
505			netdev_warn(dev, "wakeup interrupt\n");
506
507		if (isrc & IRQ_TI) {
508			/* transmission complete interrupt */
509			stats->tx_bytes += priv->read_reg(priv, REG_FI) & 0xf;
510			stats->tx_packets++;
511			can_get_echo_skb(dev, 0);
512			netif_wake_queue(dev);
513		}
514		if (isrc & IRQ_RI) {
515			/* receive interrupt */
516			while (status & SR_RBS) {
517				sja1000_rx(dev);
518				status = priv->read_reg(priv, REG_SR);
519				/* check for absent controller */
520				if (status == 0xFF && sja1000_is_absent(priv))
521					return IRQ_NONE;
522			}
523		}
524		if (isrc & (IRQ_DOI | IRQ_EI | IRQ_BEI | IRQ_EPI | IRQ_ALI)) {
525			/* error interrupt */
526			if (sja1000_err(dev, isrc, status))
527				break;
528		}
529	}
530
531	if (priv->post_irq)
532		priv->post_irq(priv);
533
534	if (n >= SJA1000_MAX_IRQ)
535		netdev_dbg(dev, "%d messages handled in ISR", n);
536
537	return (n) ? IRQ_HANDLED : IRQ_NONE;
538}
539EXPORT_SYMBOL_GPL(sja1000_interrupt);
540
541static int sja1000_open(struct net_device *dev)
542{
543	struct sja1000_priv *priv = netdev_priv(dev);
544	int err;
545
546	/* set chip into reset mode */
547	set_reset_mode(dev);
548
549	/* common open */
550	err = open_candev(dev);
551	if (err)
552		return err;
553
554	/* register interrupt handler, if not done by the device driver */
555	if (!(priv->flags & SJA1000_CUSTOM_IRQ_HANDLER)) {
556		err = request_irq(dev->irq, sja1000_interrupt, priv->irq_flags,
557				  dev->name, (void *)dev);
558		if (err) {
559			close_candev(dev);
560			return -EAGAIN;
561		}
562	}
563
564	/* init and start chi */
565	sja1000_start(dev);
566	priv->open_time = jiffies;
567
568	netif_start_queue(dev);
569
570	return 0;
571}
572
573static int sja1000_close(struct net_device *dev)
574{
575	struct sja1000_priv *priv = netdev_priv(dev);
576
577	netif_stop_queue(dev);
578	set_reset_mode(dev);
579
580	if (!(priv->flags & SJA1000_CUSTOM_IRQ_HANDLER))
581		free_irq(dev->irq, (void *)dev);
582
583	close_candev(dev);
584
585	priv->open_time = 0;
586
587	return 0;
588}
589
590struct net_device *alloc_sja1000dev(int sizeof_priv)
591{
592	struct net_device *dev;
593	struct sja1000_priv *priv;
594
595	dev = alloc_candev(sizeof(struct sja1000_priv) + sizeof_priv,
596		SJA1000_ECHO_SKB_MAX);
597	if (!dev)
598		return NULL;
599
600	priv = netdev_priv(dev);
601
602	priv->dev = dev;
603	priv->can.bittiming_const = &sja1000_bittiming_const;
604	priv->can.do_set_bittiming = sja1000_set_bittiming;
605	priv->can.do_set_mode = sja1000_set_mode;
606	priv->can.do_get_berr_counter = sja1000_get_berr_counter;
607	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
608		CAN_CTRLMODE_BERR_REPORTING;
609
610	spin_lock_init(&priv->cmdreg_lock);
611
612	if (sizeof_priv)
613		priv->priv = (void *)priv + sizeof(struct sja1000_priv);
614
615	return dev;
616}
617EXPORT_SYMBOL_GPL(alloc_sja1000dev);
618
619void free_sja1000dev(struct net_device *dev)
620{
621	free_candev(dev);
622}
623EXPORT_SYMBOL_GPL(free_sja1000dev);
624
625static const struct net_device_ops sja1000_netdev_ops = {
626       .ndo_open               = sja1000_open,
627       .ndo_stop               = sja1000_close,
628       .ndo_start_xmit         = sja1000_start_xmit,
629};
630
631int register_sja1000dev(struct net_device *dev)
632{
633	if (!sja1000_probe_chip(dev))
634		return -ENODEV;
635
636	dev->flags |= IFF_ECHO;	/* we support local echo */
637	dev->netdev_ops = &sja1000_netdev_ops;
638
639	set_reset_mode(dev);
640	chipset_init(dev);
641
642	return register_candev(dev);
643}
644EXPORT_SYMBOL_GPL(register_sja1000dev);
645
646void unregister_sja1000dev(struct net_device *dev)
647{
648	set_reset_mode(dev);
649	unregister_candev(dev);
650}
651EXPORT_SYMBOL_GPL(unregister_sja1000dev);
652
653static __init int sja1000_init(void)
654{
655	printk(KERN_INFO "%s CAN netdevice driver\n", DRV_NAME);
656
657	return 0;
658}
659
660module_init(sja1000_init);
661
662static __exit void sja1000_exit(void)
663{
664	printk(KERN_INFO "%s: driver removed\n", DRV_NAME);
665}
666
667module_exit(sja1000_exit);
668