xref: /linux/drivers/net/can/cc770/cc770.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /*
2  * Core driver for the CC770 and AN82527 CAN controllers
3  *
4  * Copyright (C) 2009, 2011 Wolfgang Grandegger <wg@grandegger.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the version 2 of the GNU General Public License
8  * as published by the Free Software Foundation
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  */
15 
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/sched.h>
22 #include <linux/types.h>
23 #include <linux/fcntl.h>
24 #include <linux/interrupt.h>
25 #include <linux/ptrace.h>
26 #include <linux/string.h>
27 #include <linux/errno.h>
28 #include <linux/netdevice.h>
29 #include <linux/if_arp.h>
30 #include <linux/if_ether.h>
31 #include <linux/skbuff.h>
32 #include <linux/delay.h>
33 
34 #include <linux/can.h>
35 #include <linux/can/dev.h>
36 #include <linux/can/error.h>
37 #include <linux/can/platform/cc770.h>
38 
39 #include "cc770.h"
40 
41 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
42 MODULE_LICENSE("GPL v2");
43 MODULE_DESCRIPTION(KBUILD_MODNAME "CAN netdevice driver");
44 
45 /*
46  * The CC770 is a CAN controller from Bosch, which is 100% compatible
47  * with the AN82527 from Intel, but with "bugs" being fixed and some
48  * additional functionality, mainly:
49  *
50  * 1. RX and TX error counters are readable.
51  * 2. Support of silent (listen-only) mode.
52  * 3. Message object 15 can receive all types of frames, also RTR and EFF.
53  *
54  * Details are available from Bosch's "CC770_Product_Info_2007-01.pdf",
55  * which explains in detail the compatibility between the CC770 and the
56  * 82527. This driver use the additional functionality 3. on real CC770
57  * devices. Unfortunately, the CC770 does still not store the message
58  * identifier of received remote transmission request frames and
59  * therefore it's set to 0.
60  *
61  * The message objects 1..14 can be used for TX and RX while the message
62  * objects 15 is optimized for RX. It has a shadow register for reliable
63  * data receiption under heavy bus load. Therefore it makes sense to use
64  * this message object for the needed use case. The frame type (EFF/SFF)
65  * for the message object 15 can be defined via kernel module parameter
66  * "msgobj15_eff". If not equal 0, it will receive 29-bit EFF frames,
67  * otherwise 11 bit SFF messages.
68  */
69 static int msgobj15_eff;
70 module_param(msgobj15_eff, int, S_IRUGO);
71 MODULE_PARM_DESC(msgobj15_eff, "Extended 29-bit frames for message object 15 "
72 		 "(default: 11-bit standard frames)");
73 
74 static int i82527_compat;
75 module_param(i82527_compat, int, S_IRUGO);
76 MODULE_PARM_DESC(i82527_compat, "Strict Intel 82527 comptibility mode "
77 		 "without using additional functions");
78 
79 /*
80  * This driver uses the last 5 message objects 11..15. The definitions
81  * and structure below allows to configure and assign them to the real
82  * message object.
83  */
84 static unsigned char cc770_obj_flags[CC770_OBJ_MAX] = {
85 	[CC770_OBJ_RX0] = CC770_OBJ_FLAG_RX,
86 	[CC770_OBJ_RX1] = CC770_OBJ_FLAG_RX | CC770_OBJ_FLAG_EFF,
87 	[CC770_OBJ_RX_RTR0] = CC770_OBJ_FLAG_RX | CC770_OBJ_FLAG_RTR,
88 	[CC770_OBJ_RX_RTR1] = CC770_OBJ_FLAG_RX | CC770_OBJ_FLAG_RTR |
89 			      CC770_OBJ_FLAG_EFF,
90 	[CC770_OBJ_TX] = 0,
91 };
92 
93 static const struct can_bittiming_const cc770_bittiming_const = {
94 	.name = KBUILD_MODNAME,
95 	.tseg1_min = 1,
96 	.tseg1_max = 16,
97 	.tseg2_min = 1,
98 	.tseg2_max = 8,
99 	.sjw_max = 4,
100 	.brp_min = 1,
101 	.brp_max = 64,
102 	.brp_inc = 1,
103 };
104 
105 static inline int intid2obj(unsigned int intid)
106 {
107 	if (intid == 2)
108 		return 0;
109 	else
110 		return MSGOBJ_LAST + 2 - intid;
111 }
112 
113 static void enable_all_objs(const struct net_device *dev)
114 {
115 	struct cc770_priv *priv = netdev_priv(dev);
116 	u8 msgcfg;
117 	unsigned char obj_flags;
118 	unsigned int o, mo;
119 
120 	for (o = 0; o < ARRAY_SIZE(priv->obj_flags); o++) {
121 		obj_flags = priv->obj_flags[o];
122 		mo = obj2msgobj(o);
123 
124 		if (obj_flags & CC770_OBJ_FLAG_RX) {
125 			/*
126 			 * We don't need extra objects for RTR and EFF if
127 			 * the additional CC770 functions are enabled.
128 			 */
129 			if (priv->control_normal_mode & CTRL_EAF) {
130 				if (o > 0)
131 					continue;
132 				netdev_dbg(dev, "Message object %d for "
133 					   "RX data, RTR, SFF and EFF\n", mo);
134 			} else {
135 				netdev_dbg(dev,
136 					   "Message object %d for RX %s %s\n",
137 					   mo, obj_flags & CC770_OBJ_FLAG_RTR ?
138 					   "RTR" : "data",
139 					   obj_flags & CC770_OBJ_FLAG_EFF ?
140 					   "EFF" : "SFF");
141 			}
142 
143 			if (obj_flags & CC770_OBJ_FLAG_EFF)
144 				msgcfg = MSGCFG_XTD;
145 			else
146 				msgcfg = 0;
147 			if (obj_flags & CC770_OBJ_FLAG_RTR)
148 				msgcfg |= MSGCFG_DIR;
149 
150 			cc770_write_reg(priv, msgobj[mo].config, msgcfg);
151 			cc770_write_reg(priv, msgobj[mo].ctrl0,
152 					MSGVAL_SET | TXIE_RES |
153 					RXIE_SET | INTPND_RES);
154 
155 			if (obj_flags & CC770_OBJ_FLAG_RTR)
156 				cc770_write_reg(priv, msgobj[mo].ctrl1,
157 						NEWDAT_RES | CPUUPD_SET |
158 						TXRQST_RES | RMTPND_RES);
159 			else
160 				cc770_write_reg(priv, msgobj[mo].ctrl1,
161 						NEWDAT_RES | MSGLST_RES |
162 						TXRQST_RES | RMTPND_RES);
163 		} else {
164 			netdev_dbg(dev, "Message object %d for "
165 				   "TX data, RTR, SFF and EFF\n", mo);
166 
167 			cc770_write_reg(priv, msgobj[mo].ctrl1,
168 					RMTPND_RES | TXRQST_RES |
169 					CPUUPD_RES | NEWDAT_RES);
170 			cc770_write_reg(priv, msgobj[mo].ctrl0,
171 					MSGVAL_RES | TXIE_RES |
172 					RXIE_RES | INTPND_RES);
173 		}
174 	}
175 }
176 
177 static void disable_all_objs(const struct cc770_priv *priv)
178 {
179 	int o, mo;
180 
181 	for (o = 0; o <  ARRAY_SIZE(priv->obj_flags); o++) {
182 		mo = obj2msgobj(o);
183 
184 		if (priv->obj_flags[o] & CC770_OBJ_FLAG_RX) {
185 			if (o > 0 && priv->control_normal_mode & CTRL_EAF)
186 				continue;
187 
188 			cc770_write_reg(priv, msgobj[mo].ctrl1,
189 					NEWDAT_RES | MSGLST_RES |
190 					TXRQST_RES | RMTPND_RES);
191 			cc770_write_reg(priv, msgobj[mo].ctrl0,
192 					MSGVAL_RES | TXIE_RES |
193 					RXIE_RES | INTPND_RES);
194 		} else {
195 			/* Clear message object for send */
196 			cc770_write_reg(priv, msgobj[mo].ctrl1,
197 					RMTPND_RES | TXRQST_RES |
198 					CPUUPD_RES | NEWDAT_RES);
199 			cc770_write_reg(priv, msgobj[mo].ctrl0,
200 					MSGVAL_RES | TXIE_RES |
201 					RXIE_RES | INTPND_RES);
202 		}
203 	}
204 }
205 
206 static void set_reset_mode(struct net_device *dev)
207 {
208 	struct cc770_priv *priv = netdev_priv(dev);
209 
210 	/* Enable configuration and puts chip in bus-off, disable interrupts */
211 	cc770_write_reg(priv, control, CTRL_CCE | CTRL_INI);
212 
213 	priv->can.state = CAN_STATE_STOPPED;
214 
215 	/* Clear interrupts */
216 	cc770_read_reg(priv, interrupt);
217 
218 	/* Clear status register */
219 	cc770_write_reg(priv, status, 0);
220 
221 	/* Disable all used message objects */
222 	disable_all_objs(priv);
223 }
224 
225 static void set_normal_mode(struct net_device *dev)
226 {
227 	struct cc770_priv *priv = netdev_priv(dev);
228 
229 	/* Clear interrupts */
230 	cc770_read_reg(priv, interrupt);
231 
232 	/* Clear status register and pre-set last error code */
233 	cc770_write_reg(priv, status, STAT_LEC_MASK);
234 
235 	/* Enable all used message objects*/
236 	enable_all_objs(dev);
237 
238 	/*
239 	 * Clear bus-off, interrupts only for errors,
240 	 * not for status change
241 	 */
242 	cc770_write_reg(priv, control, priv->control_normal_mode);
243 
244 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
245 }
246 
247 static void chipset_init(struct cc770_priv *priv)
248 {
249 	int mo, id, data;
250 
251 	/* Enable configuration and put chip in bus-off, disable interrupts */
252 	cc770_write_reg(priv, control, (CTRL_CCE | CTRL_INI));
253 
254 	/* Set CLKOUT divider and slew rates */
255 	cc770_write_reg(priv, clkout, priv->clkout);
256 
257 	/* Configure CPU interface / CLKOUT enable */
258 	cc770_write_reg(priv, cpu_interface, priv->cpu_interface);
259 
260 	/* Set bus configuration  */
261 	cc770_write_reg(priv, bus_config, priv->bus_config);
262 
263 	/* Clear interrupts */
264 	cc770_read_reg(priv, interrupt);
265 
266 	/* Clear status register */
267 	cc770_write_reg(priv, status, 0);
268 
269 	/* Clear and invalidate message objects */
270 	for (mo = MSGOBJ_FIRST; mo <= MSGOBJ_LAST; mo++) {
271 		cc770_write_reg(priv, msgobj[mo].ctrl0,
272 				INTPND_UNC | RXIE_RES |
273 				TXIE_RES | MSGVAL_RES);
274 		cc770_write_reg(priv, msgobj[mo].ctrl0,
275 				INTPND_RES | RXIE_RES |
276 				TXIE_RES | MSGVAL_RES);
277 		cc770_write_reg(priv, msgobj[mo].ctrl1,
278 				NEWDAT_RES | MSGLST_RES |
279 				TXRQST_RES | RMTPND_RES);
280 		for (data = 0; data < 8; data++)
281 			cc770_write_reg(priv, msgobj[mo].data[data], 0);
282 		for (id = 0; id < 4; id++)
283 			cc770_write_reg(priv, msgobj[mo].id[id], 0);
284 		cc770_write_reg(priv, msgobj[mo].config, 0);
285 	}
286 
287 	/* Set all global ID masks to "don't care" */
288 	cc770_write_reg(priv, global_mask_std[0], 0);
289 	cc770_write_reg(priv, global_mask_std[1], 0);
290 	cc770_write_reg(priv, global_mask_ext[0], 0);
291 	cc770_write_reg(priv, global_mask_ext[1], 0);
292 	cc770_write_reg(priv, global_mask_ext[2], 0);
293 	cc770_write_reg(priv, global_mask_ext[3], 0);
294 
295 }
296 
297 static int cc770_probe_chip(struct net_device *dev)
298 {
299 	struct cc770_priv *priv = netdev_priv(dev);
300 
301 	/* Enable configuration, put chip in bus-off, disable ints */
302 	cc770_write_reg(priv, control, CTRL_CCE | CTRL_EAF | CTRL_INI);
303 	/* Configure cpu interface / CLKOUT disable */
304 	cc770_write_reg(priv, cpu_interface, priv->cpu_interface);
305 
306 	/*
307 	 * Check if hardware reset is still inactive or maybe there
308 	 * is no chip in this address space
309 	 */
310 	if (cc770_read_reg(priv, cpu_interface) & CPUIF_RST) {
311 		netdev_info(dev, "probing @0x%p failed (reset)\n",
312 			    priv->reg_base);
313 		return -ENODEV;
314 	}
315 
316 	/* Write and read back test pattern (some arbitrary values) */
317 	cc770_write_reg(priv, msgobj[1].data[1], 0x25);
318 	cc770_write_reg(priv, msgobj[2].data[3], 0x52);
319 	cc770_write_reg(priv, msgobj[10].data[6], 0xc3);
320 	if ((cc770_read_reg(priv, msgobj[1].data[1]) != 0x25) ||
321 	    (cc770_read_reg(priv, msgobj[2].data[3]) != 0x52) ||
322 	    (cc770_read_reg(priv, msgobj[10].data[6]) != 0xc3)) {
323 		netdev_info(dev, "probing @0x%p failed (pattern)\n",
324 			    priv->reg_base);
325 		return -ENODEV;
326 	}
327 
328 	/* Check if this chip is a CC770 supporting additional functions */
329 	if (cc770_read_reg(priv, control) & CTRL_EAF)
330 		priv->control_normal_mode |= CTRL_EAF;
331 
332 	return 0;
333 }
334 
335 static void cc770_start(struct net_device *dev)
336 {
337 	struct cc770_priv *priv = netdev_priv(dev);
338 
339 	/* leave reset mode */
340 	if (priv->can.state != CAN_STATE_STOPPED)
341 		set_reset_mode(dev);
342 
343 	/* leave reset mode */
344 	set_normal_mode(dev);
345 }
346 
347 static int cc770_set_mode(struct net_device *dev, enum can_mode mode)
348 {
349 	switch (mode) {
350 	case CAN_MODE_START:
351 		cc770_start(dev);
352 		netif_wake_queue(dev);
353 		break;
354 
355 	default:
356 		return -EOPNOTSUPP;
357 	}
358 
359 	return 0;
360 }
361 
362 static int cc770_set_bittiming(struct net_device *dev)
363 {
364 	struct cc770_priv *priv = netdev_priv(dev);
365 	struct can_bittiming *bt = &priv->can.bittiming;
366 	u8 btr0, btr1;
367 
368 	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
369 	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
370 		(((bt->phase_seg2 - 1) & 0x7) << 4);
371 	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
372 		btr1 |= 0x80;
373 
374 	netdev_info(dev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
375 
376 	cc770_write_reg(priv, bit_timing_0, btr0);
377 	cc770_write_reg(priv, bit_timing_1, btr1);
378 
379 	return 0;
380 }
381 
382 static int cc770_get_berr_counter(const struct net_device *dev,
383 				  struct can_berr_counter *bec)
384 {
385 	struct cc770_priv *priv = netdev_priv(dev);
386 
387 	bec->txerr = cc770_read_reg(priv, tx_error_counter);
388 	bec->rxerr = cc770_read_reg(priv, rx_error_counter);
389 
390 	return 0;
391 }
392 
393 static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev)
394 {
395 	struct cc770_priv *priv = netdev_priv(dev);
396 	struct net_device_stats *stats = &dev->stats;
397 	struct can_frame *cf = (struct can_frame *)skb->data;
398 	unsigned int mo = obj2msgobj(CC770_OBJ_TX);
399 	u8 dlc, rtr;
400 	u32 id;
401 	int i;
402 
403 	if (can_dropped_invalid_skb(dev, skb))
404 		return NETDEV_TX_OK;
405 
406 	if ((cc770_read_reg(priv,
407 			    msgobj[mo].ctrl1) & TXRQST_UNC) == TXRQST_SET) {
408 		netdev_err(dev, "TX register is still occupied!\n");
409 		return NETDEV_TX_BUSY;
410 	}
411 
412 	netif_stop_queue(dev);
413 
414 	dlc = cf->can_dlc;
415 	id = cf->can_id;
416 	if (cf->can_id & CAN_RTR_FLAG)
417 		rtr = 0;
418 	else
419 		rtr = MSGCFG_DIR;
420 	cc770_write_reg(priv, msgobj[mo].ctrl1,
421 			RMTPND_RES | TXRQST_RES | CPUUPD_SET | NEWDAT_RES);
422 	cc770_write_reg(priv, msgobj[mo].ctrl0,
423 			MSGVAL_SET | TXIE_SET | RXIE_RES | INTPND_RES);
424 	if (id & CAN_EFF_FLAG) {
425 		id &= CAN_EFF_MASK;
426 		cc770_write_reg(priv, msgobj[mo].config,
427 				(dlc << 4) | rtr | MSGCFG_XTD);
428 		cc770_write_reg(priv, msgobj[mo].id[3], id << 3);
429 		cc770_write_reg(priv, msgobj[mo].id[2], id >> 5);
430 		cc770_write_reg(priv, msgobj[mo].id[1], id >> 13);
431 		cc770_write_reg(priv, msgobj[mo].id[0], id >> 21);
432 	} else {
433 		id &= CAN_SFF_MASK;
434 		cc770_write_reg(priv, msgobj[mo].config, (dlc << 4) | rtr);
435 		cc770_write_reg(priv, msgobj[mo].id[0], id >> 3);
436 		cc770_write_reg(priv, msgobj[mo].id[1], id << 5);
437 	}
438 
439 	for (i = 0; i < dlc; i++)
440 		cc770_write_reg(priv, msgobj[mo].data[i], cf->data[i]);
441 
442 	/* Store echo skb before starting the transfer */
443 	can_put_echo_skb(skb, dev, 0);
444 
445 	cc770_write_reg(priv, msgobj[mo].ctrl1,
446 			RMTPND_RES | TXRQST_SET | CPUUPD_RES | NEWDAT_UNC);
447 
448 	stats->tx_bytes += dlc;
449 
450 
451 	/*
452 	 * HM: We had some cases of repeated IRQs so make sure the
453 	 * INT is acknowledged I know it's already further up, but
454 	 * doing again fixed the issue
455 	 */
456 	cc770_write_reg(priv, msgobj[mo].ctrl0,
457 			MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES);
458 
459 	return NETDEV_TX_OK;
460 }
461 
462 static void cc770_rx(struct net_device *dev, unsigned int mo, u8 ctrl1)
463 {
464 	struct cc770_priv *priv = netdev_priv(dev);
465 	struct net_device_stats *stats = &dev->stats;
466 	struct can_frame *cf;
467 	struct sk_buff *skb;
468 	u8 config;
469 	u32 id;
470 	int i;
471 
472 	skb = alloc_can_skb(dev, &cf);
473 	if (!skb)
474 		return;
475 
476 	config = cc770_read_reg(priv, msgobj[mo].config);
477 
478 	if (ctrl1 & RMTPND_SET) {
479 		/*
480 		 * Unfortunately, the chip does not store the real message
481 		 * identifier of the received remote transmission request
482 		 * frame. Therefore we set it to 0.
483 		 */
484 		cf->can_id = CAN_RTR_FLAG;
485 		if (config & MSGCFG_XTD)
486 			cf->can_id |= CAN_EFF_FLAG;
487 		cf->can_dlc = 0;
488 	} else {
489 		if (config & MSGCFG_XTD) {
490 			id = cc770_read_reg(priv, msgobj[mo].id[3]);
491 			id |= cc770_read_reg(priv, msgobj[mo].id[2]) << 8;
492 			id |= cc770_read_reg(priv, msgobj[mo].id[1]) << 16;
493 			id |= cc770_read_reg(priv, msgobj[mo].id[0]) << 24;
494 			id >>= 3;
495 			id |= CAN_EFF_FLAG;
496 		} else {
497 			id = cc770_read_reg(priv, msgobj[mo].id[1]);
498 			id |= cc770_read_reg(priv, msgobj[mo].id[0]) << 8;
499 			id >>= 5;
500 		}
501 
502 		cf->can_id = id;
503 		cf->can_dlc = get_can_dlc((config & 0xf0) >> 4);
504 		for (i = 0; i < cf->can_dlc; i++)
505 			cf->data[i] = cc770_read_reg(priv, msgobj[mo].data[i]);
506 	}
507 	netif_rx(skb);
508 
509 	stats->rx_packets++;
510 	stats->rx_bytes += cf->can_dlc;
511 }
512 
513 static int cc770_err(struct net_device *dev, u8 status)
514 {
515 	struct cc770_priv *priv = netdev_priv(dev);
516 	struct net_device_stats *stats = &dev->stats;
517 	struct can_frame *cf;
518 	struct sk_buff *skb;
519 	u8 lec;
520 
521 	netdev_dbg(dev, "status interrupt (%#x)\n", status);
522 
523 	skb = alloc_can_err_skb(dev, &cf);
524 	if (!skb)
525 		return -ENOMEM;
526 
527 	/* Use extended functions of the CC770 */
528 	if (priv->control_normal_mode & CTRL_EAF) {
529 		cf->data[6] = cc770_read_reg(priv, tx_error_counter);
530 		cf->data[7] = cc770_read_reg(priv, rx_error_counter);
531 	}
532 
533 	if (status & STAT_BOFF) {
534 		/* Disable interrupts */
535 		cc770_write_reg(priv, control, CTRL_INI);
536 		cf->can_id |= CAN_ERR_BUSOFF;
537 		priv->can.state = CAN_STATE_BUS_OFF;
538 		can_bus_off(dev);
539 	} else if (status & STAT_WARN) {
540 		cf->can_id |= CAN_ERR_CRTL;
541 		/* Only the CC770 does show error passive */
542 		if (cf->data[7] > 127) {
543 			cf->data[1] = CAN_ERR_CRTL_RX_PASSIVE |
544 				CAN_ERR_CRTL_TX_PASSIVE;
545 			priv->can.state = CAN_STATE_ERROR_PASSIVE;
546 			priv->can.can_stats.error_passive++;
547 		} else {
548 			cf->data[1] = CAN_ERR_CRTL_RX_WARNING |
549 				CAN_ERR_CRTL_TX_WARNING;
550 			priv->can.state = CAN_STATE_ERROR_WARNING;
551 			priv->can.can_stats.error_warning++;
552 		}
553 	} else {
554 		/* Back to error avtive */
555 		cf->can_id |= CAN_ERR_PROT;
556 		cf->data[2] = CAN_ERR_PROT_ACTIVE;
557 		priv->can.state = CAN_STATE_ERROR_ACTIVE;
558 	}
559 
560 	lec = status & STAT_LEC_MASK;
561 	if (lec < 7 && lec > 0) {
562 		if (lec == STAT_LEC_ACK) {
563 			cf->can_id |= CAN_ERR_ACK;
564 		} else {
565 			cf->can_id |= CAN_ERR_PROT;
566 			switch (lec) {
567 			case STAT_LEC_STUFF:
568 				cf->data[2] |= CAN_ERR_PROT_STUFF;
569 				break;
570 			case STAT_LEC_FORM:
571 				cf->data[2] |= CAN_ERR_PROT_FORM;
572 				break;
573 			case STAT_LEC_BIT1:
574 				cf->data[2] |= CAN_ERR_PROT_BIT1;
575 				break;
576 			case STAT_LEC_BIT0:
577 				cf->data[2] |= CAN_ERR_PROT_BIT0;
578 				break;
579 			case STAT_LEC_CRC:
580 				cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
581 				break;
582 			}
583 		}
584 	}
585 
586 	netif_rx(skb);
587 
588 	stats->rx_packets++;
589 	stats->rx_bytes += cf->can_dlc;
590 
591 	return 0;
592 }
593 
594 static int cc770_status_interrupt(struct net_device *dev)
595 {
596 	struct cc770_priv *priv = netdev_priv(dev);
597 	u8 status;
598 
599 	status = cc770_read_reg(priv, status);
600 	/* Reset the status register including RXOK and TXOK */
601 	cc770_write_reg(priv, status, STAT_LEC_MASK);
602 
603 	if (status & (STAT_WARN | STAT_BOFF) ||
604 	    (status & STAT_LEC_MASK) != STAT_LEC_MASK) {
605 		cc770_err(dev, status);
606 		return status & STAT_BOFF;
607 	}
608 
609 	return 0;
610 }
611 
612 static void cc770_rx_interrupt(struct net_device *dev, unsigned int o)
613 {
614 	struct cc770_priv *priv = netdev_priv(dev);
615 	struct net_device_stats *stats = &dev->stats;
616 	unsigned int mo = obj2msgobj(o);
617 	u8 ctrl1;
618 	int n = CC770_MAX_MSG;
619 
620 	while (n--) {
621 		ctrl1 = cc770_read_reg(priv, msgobj[mo].ctrl1);
622 
623 		if (!(ctrl1 & NEWDAT_SET))  {
624 			/* Check for RTR if additional functions are enabled */
625 			if (priv->control_normal_mode & CTRL_EAF) {
626 				if (!(cc770_read_reg(priv, msgobj[mo].ctrl0) &
627 				      INTPND_SET))
628 					break;
629 			} else {
630 				break;
631 			}
632 		}
633 
634 		if (ctrl1 & MSGLST_SET) {
635 			stats->rx_over_errors++;
636 			stats->rx_errors++;
637 		}
638 		if (mo < MSGOBJ_LAST)
639 			cc770_write_reg(priv, msgobj[mo].ctrl1,
640 					NEWDAT_RES | MSGLST_RES |
641 					TXRQST_UNC | RMTPND_UNC);
642 		cc770_rx(dev, mo, ctrl1);
643 
644 		cc770_write_reg(priv, msgobj[mo].ctrl0,
645 				MSGVAL_SET | TXIE_RES |
646 				RXIE_SET | INTPND_RES);
647 		cc770_write_reg(priv, msgobj[mo].ctrl1,
648 				NEWDAT_RES | MSGLST_RES |
649 				TXRQST_RES | RMTPND_RES);
650 	}
651 }
652 
653 static void cc770_rtr_interrupt(struct net_device *dev, unsigned int o)
654 {
655 	struct cc770_priv *priv = netdev_priv(dev);
656 	unsigned int mo = obj2msgobj(o);
657 	u8 ctrl0, ctrl1;
658 	int n = CC770_MAX_MSG;
659 
660 	while (n--) {
661 		ctrl0 = cc770_read_reg(priv, msgobj[mo].ctrl0);
662 		if (!(ctrl0 & INTPND_SET))
663 			break;
664 
665 		ctrl1 = cc770_read_reg(priv, msgobj[mo].ctrl1);
666 		cc770_rx(dev, mo, ctrl1);
667 
668 		cc770_write_reg(priv, msgobj[mo].ctrl0,
669 				MSGVAL_SET | TXIE_RES |
670 				RXIE_SET | INTPND_RES);
671 		cc770_write_reg(priv, msgobj[mo].ctrl1,
672 				NEWDAT_RES | CPUUPD_SET |
673 				TXRQST_RES | RMTPND_RES);
674 	}
675 }
676 
677 static void cc770_tx_interrupt(struct net_device *dev, unsigned int o)
678 {
679 	struct cc770_priv *priv = netdev_priv(dev);
680 	struct net_device_stats *stats = &dev->stats;
681 	unsigned int mo = obj2msgobj(o);
682 
683 	/* Nothing more to send, switch off interrupts */
684 	cc770_write_reg(priv, msgobj[mo].ctrl0,
685 			MSGVAL_RES | TXIE_RES | RXIE_RES | INTPND_RES);
686 	/*
687 	 * We had some cases of repeated IRQ so make sure the
688 	 * INT is acknowledged
689 	 */
690 	cc770_write_reg(priv, msgobj[mo].ctrl0,
691 			MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES);
692 
693 	stats->tx_packets++;
694 	can_get_echo_skb(dev, 0);
695 	netif_wake_queue(dev);
696 }
697 
698 static irqreturn_t cc770_interrupt(int irq, void *dev_id)
699 {
700 	struct net_device *dev = (struct net_device *)dev_id;
701 	struct cc770_priv *priv = netdev_priv(dev);
702 	u8 intid;
703 	int o, n = 0;
704 
705 	/* Shared interrupts and IRQ off? */
706 	if (priv->can.state == CAN_STATE_STOPPED)
707 		return IRQ_NONE;
708 
709 	if (priv->pre_irq)
710 		priv->pre_irq(priv);
711 
712 	while (n < CC770_MAX_IRQ) {
713 		/* Read the highest pending interrupt request */
714 		intid = cc770_read_reg(priv, interrupt);
715 		if (!intid)
716 			break;
717 		n++;
718 
719 		if (intid == 1) {
720 			/* Exit in case of bus-off */
721 			if (cc770_status_interrupt(dev))
722 				break;
723 		} else {
724 			o = intid2obj(intid);
725 
726 			if (o >= CC770_OBJ_MAX) {
727 				netdev_err(dev, "Unexpected interrupt id %d\n",
728 					   intid);
729 				continue;
730 			}
731 
732 			if (priv->obj_flags[o] & CC770_OBJ_FLAG_RTR)
733 				cc770_rtr_interrupt(dev, o);
734 			else if (priv->obj_flags[o] & CC770_OBJ_FLAG_RX)
735 				cc770_rx_interrupt(dev, o);
736 			else
737 				cc770_tx_interrupt(dev, o);
738 		}
739 	}
740 
741 	if (priv->post_irq)
742 		priv->post_irq(priv);
743 
744 	if (n >= CC770_MAX_IRQ)
745 		netdev_dbg(dev, "%d messages handled in ISR", n);
746 
747 	return (n) ? IRQ_HANDLED : IRQ_NONE;
748 }
749 
750 static int cc770_open(struct net_device *dev)
751 {
752 	struct cc770_priv *priv = netdev_priv(dev);
753 	int err;
754 
755 	/* set chip into reset mode */
756 	set_reset_mode(dev);
757 
758 	/* common open */
759 	err = open_candev(dev);
760 	if (err)
761 		return err;
762 
763 	err = request_irq(dev->irq, &cc770_interrupt, priv->irq_flags,
764 			  dev->name, dev);
765 	if (err) {
766 		close_candev(dev);
767 		return -EAGAIN;
768 	}
769 
770 	/* init and start chip */
771 	cc770_start(dev);
772 
773 	netif_start_queue(dev);
774 
775 	return 0;
776 }
777 
778 static int cc770_close(struct net_device *dev)
779 {
780 	netif_stop_queue(dev);
781 	set_reset_mode(dev);
782 
783 	free_irq(dev->irq, dev);
784 	close_candev(dev);
785 
786 	return 0;
787 }
788 
789 struct net_device *alloc_cc770dev(int sizeof_priv)
790 {
791 	struct net_device *dev;
792 	struct cc770_priv *priv;
793 
794 	dev = alloc_candev(sizeof(struct cc770_priv) + sizeof_priv,
795 			   CC770_ECHO_SKB_MAX);
796 	if (!dev)
797 		return NULL;
798 
799 	priv = netdev_priv(dev);
800 
801 	priv->dev = dev;
802 	priv->can.bittiming_const = &cc770_bittiming_const;
803 	priv->can.do_set_bittiming = cc770_set_bittiming;
804 	priv->can.do_set_mode = cc770_set_mode;
805 	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
806 
807 	memcpy(priv->obj_flags, cc770_obj_flags, sizeof(cc770_obj_flags));
808 
809 	if (sizeof_priv)
810 		priv->priv = (void *)priv + sizeof(struct cc770_priv);
811 
812 	return dev;
813 }
814 EXPORT_SYMBOL_GPL(alloc_cc770dev);
815 
816 void free_cc770dev(struct net_device *dev)
817 {
818 	free_candev(dev);
819 }
820 EXPORT_SYMBOL_GPL(free_cc770dev);
821 
822 static const struct net_device_ops cc770_netdev_ops = {
823 	.ndo_open = cc770_open,
824 	.ndo_stop = cc770_close,
825 	.ndo_start_xmit = cc770_start_xmit,
826 };
827 
828 int register_cc770dev(struct net_device *dev)
829 {
830 	struct cc770_priv *priv = netdev_priv(dev);
831 	int err;
832 
833 	err = cc770_probe_chip(dev);
834 	if (err)
835 		return err;
836 
837 	dev->netdev_ops = &cc770_netdev_ops;
838 
839 	dev->flags |= IFF_ECHO;	/* we support local echo */
840 
841 	/* Should we use additional functions? */
842 	if (!i82527_compat && priv->control_normal_mode & CTRL_EAF) {
843 		priv->can.do_get_berr_counter = cc770_get_berr_counter;
844 		priv->control_normal_mode = CTRL_IE | CTRL_EAF | CTRL_EIE;
845 		netdev_dbg(dev, "i82527 mode with additional functions\n");
846 	} else {
847 		priv->control_normal_mode = CTRL_IE | CTRL_EIE;
848 		netdev_dbg(dev, "strict i82527 compatibility mode\n");
849 	}
850 
851 	chipset_init(priv);
852 	set_reset_mode(dev);
853 
854 	return register_candev(dev);
855 }
856 EXPORT_SYMBOL_GPL(register_cc770dev);
857 
858 void unregister_cc770dev(struct net_device *dev)
859 {
860 	set_reset_mode(dev);
861 	unregister_candev(dev);
862 }
863 EXPORT_SYMBOL_GPL(unregister_cc770dev);
864 
865 static __init int cc770_init(void)
866 {
867 	if (msgobj15_eff) {
868 		cc770_obj_flags[CC770_OBJ_RX0] |= CC770_OBJ_FLAG_EFF;
869 		cc770_obj_flags[CC770_OBJ_RX1] &= ~CC770_OBJ_FLAG_EFF;
870 	}
871 
872 	pr_info("CAN netdevice driver\n");
873 
874 	return 0;
875 }
876 module_init(cc770_init);
877 
878 static __exit void cc770_exit(void)
879 {
880 	pr_info("driver removed\n");
881 }
882 module_exit(cc770_exit);
883