1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2005-2007  Kristian Hoegsberg <krh@bitplanet.net>
4  */
5 
6 #include <linux/bug.h>
7 #include <linux/completion.h>
8 #include <linux/crc-itu-t.h>
9 #include <linux/device.h>
10 #include <linux/errno.h>
11 #include <linux/firewire.h>
12 #include <linux/firewire-constants.h>
13 #include <linux/jiffies.h>
14 #include <linux/kernel.h>
15 #include <linux/kref.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/spinlock.h>
20 #include <linux/workqueue.h>
21 
22 #include <linux/atomic.h>
23 #include <asm/byteorder.h>
24 
25 #include "core.h"
26 
27 #define define_fw_printk_level(func, kern_level)		\
28 void func(const struct fw_card *card, const char *fmt, ...)	\
29 {								\
30 	struct va_format vaf;					\
31 	va_list args;						\
32 								\
33 	va_start(args, fmt);					\
34 	vaf.fmt = fmt;						\
35 	vaf.va = &args;						\
36 	printk(kern_level KBUILD_MODNAME " %s: %pV",		\
37 	       dev_name(card->device), &vaf);			\
38 	va_end(args);						\
39 }
40 define_fw_printk_level(fw_err, KERN_ERR);
41 define_fw_printk_level(fw_notice, KERN_NOTICE);
42 
fw_compute_block_crc(__be32 * block)43 int fw_compute_block_crc(__be32 *block)
44 {
45 	int length;
46 	u16 crc;
47 
48 	length = (be32_to_cpu(block[0]) >> 16) & 0xff;
49 	crc = crc_itu_t(0, (u8 *)&block[1], length * 4);
50 	*block |= cpu_to_be32(crc);
51 
52 	return length;
53 }
54 
55 static DEFINE_MUTEX(card_mutex);
56 static LIST_HEAD(card_list);
57 
58 static LIST_HEAD(descriptor_list);
59 static int descriptor_count;
60 
61 static __be32 tmp_config_rom[256];
62 /* ROM header, bus info block, root dir header, capabilities = 7 quadlets */
63 static size_t config_rom_length = 1 + 4 + 1 + 1;
64 
65 #define BIB_CRC(v)		((v) <<  0)
66 #define BIB_CRC_LENGTH(v)	((v) << 16)
67 #define BIB_INFO_LENGTH(v)	((v) << 24)
68 #define BIB_BUS_NAME		0x31333934 /* "1394" */
69 #define BIB_LINK_SPEED(v)	((v) <<  0)
70 #define BIB_GENERATION(v)	((v) <<  4)
71 #define BIB_MAX_ROM(v)		((v) <<  8)
72 #define BIB_MAX_RECEIVE(v)	((v) << 12)
73 #define BIB_CYC_CLK_ACC(v)	((v) << 16)
74 #define BIB_PMC			((1) << 27)
75 #define BIB_BMC			((1) << 28)
76 #define BIB_ISC			((1) << 29)
77 #define BIB_CMC			((1) << 30)
78 #define BIB_IRMC		((1) << 31)
79 #define NODE_CAPABILITIES	0x0c0083c0 /* per IEEE 1394 clause 8.3.2.6.5.2 */
80 
81 /*
82  * IEEE-1394 specifies a default SPLIT_TIMEOUT value of 800 cycles (100 ms),
83  * but we have to make it longer because there are many devices whose firmware
84  * is just too slow for that.
85  */
86 #define DEFAULT_SPLIT_TIMEOUT	(2 * 8000)
87 
88 #define CANON_OUI		0x000085
89 
generate_config_rom(struct fw_card * card,__be32 * config_rom)90 static void generate_config_rom(struct fw_card *card, __be32 *config_rom)
91 {
92 	struct fw_descriptor *desc;
93 	int i, j, k, length;
94 
95 	/*
96 	 * Initialize contents of config rom buffer.  On the OHCI
97 	 * controller, block reads to the config rom accesses the host
98 	 * memory, but quadlet read access the hardware bus info block
99 	 * registers.  That's just crack, but it means we should make
100 	 * sure the contents of bus info block in host memory matches
101 	 * the version stored in the OHCI registers.
102 	 */
103 
104 	config_rom[0] = cpu_to_be32(
105 		BIB_CRC_LENGTH(4) | BIB_INFO_LENGTH(4) | BIB_CRC(0));
106 	config_rom[1] = cpu_to_be32(BIB_BUS_NAME);
107 	config_rom[2] = cpu_to_be32(
108 		BIB_LINK_SPEED(card->link_speed) |
109 		BIB_GENERATION(card->config_rom_generation++ % 14 + 2) |
110 		BIB_MAX_ROM(2) |
111 		BIB_MAX_RECEIVE(card->max_receive) |
112 		BIB_BMC | BIB_ISC | BIB_CMC | BIB_IRMC);
113 	config_rom[3] = cpu_to_be32(card->guid >> 32);
114 	config_rom[4] = cpu_to_be32(card->guid);
115 
116 	/* Generate root directory. */
117 	config_rom[6] = cpu_to_be32(NODE_CAPABILITIES);
118 	i = 7;
119 	j = 7 + descriptor_count;
120 
121 	/* Generate root directory entries for descriptors. */
122 	list_for_each_entry (desc, &descriptor_list, link) {
123 		if (desc->immediate > 0)
124 			config_rom[i++] = cpu_to_be32(desc->immediate);
125 		config_rom[i] = cpu_to_be32(desc->key | (j - i));
126 		i++;
127 		j += desc->length;
128 	}
129 
130 	/* Update root directory length. */
131 	config_rom[5] = cpu_to_be32((i - 5 - 1) << 16);
132 
133 	/* End of root directory, now copy in descriptors. */
134 	list_for_each_entry (desc, &descriptor_list, link) {
135 		for (k = 0; k < desc->length; k++)
136 			config_rom[i + k] = cpu_to_be32(desc->data[k]);
137 		i += desc->length;
138 	}
139 
140 	/* Calculate CRCs for all blocks in the config rom.  This
141 	 * assumes that CRC length and info length are identical for
142 	 * the bus info block, which is always the case for this
143 	 * implementation. */
144 	for (i = 0; i < j; i += length + 1)
145 		length = fw_compute_block_crc(config_rom + i);
146 
147 	WARN_ON(j != config_rom_length);
148 }
149 
update_config_roms(void)150 static void update_config_roms(void)
151 {
152 	struct fw_card *card;
153 
154 	list_for_each_entry (card, &card_list, link) {
155 		generate_config_rom(card, tmp_config_rom);
156 		card->driver->set_config_rom(card, tmp_config_rom,
157 					     config_rom_length);
158 	}
159 }
160 
required_space(struct fw_descriptor * desc)161 static size_t required_space(struct fw_descriptor *desc)
162 {
163 	/* descriptor + entry into root dir + optional immediate entry */
164 	return desc->length + 1 + (desc->immediate > 0 ? 1 : 0);
165 }
166 
fw_core_add_descriptor(struct fw_descriptor * desc)167 int fw_core_add_descriptor(struct fw_descriptor *desc)
168 {
169 	size_t i;
170 	int ret;
171 
172 	/*
173 	 * Check descriptor is valid; the length of all blocks in the
174 	 * descriptor has to add up to exactly the length of the
175 	 * block.
176 	 */
177 	i = 0;
178 	while (i < desc->length)
179 		i += (desc->data[i] >> 16) + 1;
180 
181 	if (i != desc->length)
182 		return -EINVAL;
183 
184 	mutex_lock(&card_mutex);
185 
186 	if (config_rom_length + required_space(desc) > 256) {
187 		ret = -EBUSY;
188 	} else {
189 		list_add_tail(&desc->link, &descriptor_list);
190 		config_rom_length += required_space(desc);
191 		descriptor_count++;
192 		if (desc->immediate > 0)
193 			descriptor_count++;
194 		update_config_roms();
195 		ret = 0;
196 	}
197 
198 	mutex_unlock(&card_mutex);
199 
200 	return ret;
201 }
202 EXPORT_SYMBOL(fw_core_add_descriptor);
203 
fw_core_remove_descriptor(struct fw_descriptor * desc)204 void fw_core_remove_descriptor(struct fw_descriptor *desc)
205 {
206 	mutex_lock(&card_mutex);
207 
208 	list_del(&desc->link);
209 	config_rom_length -= required_space(desc);
210 	descriptor_count--;
211 	if (desc->immediate > 0)
212 		descriptor_count--;
213 	update_config_roms();
214 
215 	mutex_unlock(&card_mutex);
216 }
217 EXPORT_SYMBOL(fw_core_remove_descriptor);
218 
reset_bus(struct fw_card * card,bool short_reset)219 static int reset_bus(struct fw_card *card, bool short_reset)
220 {
221 	int reg = short_reset ? 5 : 1;
222 	int bit = short_reset ? PHY_BUS_SHORT_RESET : PHY_BUS_RESET;
223 
224 	return card->driver->update_phy_reg(card, reg, 0, bit);
225 }
226 
fw_schedule_bus_reset(struct fw_card * card,bool delayed,bool short_reset)227 void fw_schedule_bus_reset(struct fw_card *card, bool delayed, bool short_reset)
228 {
229 	/* We don't try hard to sort out requests of long vs. short resets. */
230 	card->br_short = short_reset;
231 
232 	/* Use an arbitrary short delay to combine multiple reset requests. */
233 	fw_card_get(card);
234 	if (!queue_delayed_work(fw_workqueue, &card->br_work,
235 				delayed ? DIV_ROUND_UP(HZ, 100) : 0))
236 		fw_card_put(card);
237 }
238 EXPORT_SYMBOL(fw_schedule_bus_reset);
239 
br_work(struct work_struct * work)240 static void br_work(struct work_struct *work)
241 {
242 	struct fw_card *card = container_of(work, struct fw_card, br_work.work);
243 
244 	/* Delay for 2s after last reset per IEEE 1394 clause 8.2.1. */
245 	if (card->reset_jiffies != 0 &&
246 	    time_before64(get_jiffies_64(), card->reset_jiffies + 2 * HZ)) {
247 		if (!queue_delayed_work(fw_workqueue, &card->br_work, 2 * HZ))
248 			fw_card_put(card);
249 		return;
250 	}
251 
252 	fw_send_phy_config(card, FW_PHY_CONFIG_NO_NODE_ID, card->generation,
253 			   FW_PHY_CONFIG_CURRENT_GAP_COUNT);
254 	reset_bus(card, card->br_short);
255 	fw_card_put(card);
256 }
257 
allocate_broadcast_channel(struct fw_card * card,int generation)258 static void allocate_broadcast_channel(struct fw_card *card, int generation)
259 {
260 	int channel, bandwidth = 0;
261 
262 	if (!card->broadcast_channel_allocated) {
263 		fw_iso_resource_manage(card, generation, 1ULL << 31,
264 				       &channel, &bandwidth, true);
265 		if (channel != 31) {
266 			fw_notice(card, "failed to allocate broadcast channel\n");
267 			return;
268 		}
269 		card->broadcast_channel_allocated = true;
270 	}
271 
272 	device_for_each_child(card->device, (void *)(long)generation,
273 			      fw_device_set_broadcast_channel);
274 }
275 
276 static const char gap_count_table[] = {
277 	63, 5, 7, 8, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40
278 };
279 
fw_schedule_bm_work(struct fw_card * card,unsigned long delay)280 void fw_schedule_bm_work(struct fw_card *card, unsigned long delay)
281 {
282 	fw_card_get(card);
283 	if (!schedule_delayed_work(&card->bm_work, delay))
284 		fw_card_put(card);
285 }
286 
bm_work(struct work_struct * work)287 static void bm_work(struct work_struct *work)
288 {
289 	struct fw_card *card = container_of(work, struct fw_card, bm_work.work);
290 	struct fw_device *root_device, *irm_device;
291 	struct fw_node *root_node;
292 	int root_id, new_root_id, irm_id, bm_id, local_id;
293 	int gap_count, generation, grace, rcode;
294 	bool do_reset = false;
295 	bool root_device_is_running;
296 	bool root_device_is_cmc;
297 	bool irm_is_1394_1995_only;
298 	bool keep_this_irm;
299 	__be32 transaction_data[2];
300 
301 	spin_lock_irq(&card->lock);
302 
303 	if (card->local_node == NULL) {
304 		spin_unlock_irq(&card->lock);
305 		goto out_put_card;
306 	}
307 
308 	generation = card->generation;
309 
310 	root_node = card->root_node;
311 	fw_node_get(root_node);
312 	root_device = root_node->data;
313 	root_device_is_running = root_device &&
314 			atomic_read(&root_device->state) == FW_DEVICE_RUNNING;
315 	root_device_is_cmc = root_device && root_device->cmc;
316 
317 	irm_device = card->irm_node->data;
318 	irm_is_1394_1995_only = irm_device && irm_device->config_rom &&
319 			(irm_device->config_rom[2] & 0x000000f0) == 0;
320 
321 	/* Canon MV5i works unreliably if it is not root node. */
322 	keep_this_irm = irm_device && irm_device->config_rom &&
323 			irm_device->config_rom[3] >> 8 == CANON_OUI;
324 
325 	root_id  = root_node->node_id;
326 	irm_id   = card->irm_node->node_id;
327 	local_id = card->local_node->node_id;
328 
329 	grace = time_after64(get_jiffies_64(),
330 			     card->reset_jiffies + DIV_ROUND_UP(HZ, 8));
331 
332 	if ((is_next_generation(generation, card->bm_generation) &&
333 	     !card->bm_abdicate) ||
334 	    (card->bm_generation != generation && grace)) {
335 		/*
336 		 * This first step is to figure out who is IRM and
337 		 * then try to become bus manager.  If the IRM is not
338 		 * well defined (e.g. does not have an active link
339 		 * layer or does not responds to our lock request, we
340 		 * will have to do a little vigilante bus management.
341 		 * In that case, we do a goto into the gap count logic
342 		 * so that when we do the reset, we still optimize the
343 		 * gap count.  That could well save a reset in the
344 		 * next generation.
345 		 */
346 
347 		if (!card->irm_node->link_on) {
348 			new_root_id = local_id;
349 			fw_notice(card, "%s, making local node (%02x) root\n",
350 				  "IRM has link off", new_root_id);
351 			goto pick_me;
352 		}
353 
354 		if (irm_is_1394_1995_only && !keep_this_irm) {
355 			new_root_id = local_id;
356 			fw_notice(card, "%s, making local node (%02x) root\n",
357 				  "IRM is not 1394a compliant", new_root_id);
358 			goto pick_me;
359 		}
360 
361 		transaction_data[0] = cpu_to_be32(0x3f);
362 		transaction_data[1] = cpu_to_be32(local_id);
363 
364 		spin_unlock_irq(&card->lock);
365 
366 		rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
367 				irm_id, generation, SCODE_100,
368 				CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
369 				transaction_data, 8);
370 
371 		if (rcode == RCODE_GENERATION)
372 			/* Another bus reset, BM work has been rescheduled. */
373 			goto out;
374 
375 		bm_id = be32_to_cpu(transaction_data[0]);
376 
377 		spin_lock_irq(&card->lock);
378 		if (rcode == RCODE_COMPLETE && generation == card->generation)
379 			card->bm_node_id =
380 			    bm_id == 0x3f ? local_id : 0xffc0 | bm_id;
381 		spin_unlock_irq(&card->lock);
382 
383 		if (rcode == RCODE_COMPLETE && bm_id != 0x3f) {
384 			/* Somebody else is BM.  Only act as IRM. */
385 			if (local_id == irm_id)
386 				allocate_broadcast_channel(card, generation);
387 
388 			goto out;
389 		}
390 
391 		if (rcode == RCODE_SEND_ERROR) {
392 			/*
393 			 * We have been unable to send the lock request due to
394 			 * some local problem.  Let's try again later and hope
395 			 * that the problem has gone away by then.
396 			 */
397 			fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 8));
398 			goto out;
399 		}
400 
401 		spin_lock_irq(&card->lock);
402 
403 		if (rcode != RCODE_COMPLETE && !keep_this_irm) {
404 			/*
405 			 * The lock request failed, maybe the IRM
406 			 * isn't really IRM capable after all. Let's
407 			 * do a bus reset and pick the local node as
408 			 * root, and thus, IRM.
409 			 */
410 			new_root_id = local_id;
411 			fw_notice(card, "BM lock failed (%s), making local node (%02x) root\n",
412 				  fw_rcode_string(rcode), new_root_id);
413 			goto pick_me;
414 		}
415 	} else if (card->bm_generation != generation) {
416 		/*
417 		 * We weren't BM in the last generation, and the last
418 		 * bus reset is less than 125ms ago.  Reschedule this job.
419 		 */
420 		spin_unlock_irq(&card->lock);
421 		fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 8));
422 		goto out;
423 	}
424 
425 	/*
426 	 * We're bus manager for this generation, so next step is to
427 	 * make sure we have an active cycle master and do gap count
428 	 * optimization.
429 	 */
430 	card->bm_generation = generation;
431 
432 	if (root_device == NULL) {
433 		/*
434 		 * Either link_on is false, or we failed to read the
435 		 * config rom.  In either case, pick another root.
436 		 */
437 		new_root_id = local_id;
438 	} else if (!root_device_is_running) {
439 		/*
440 		 * If we haven't probed this device yet, bail out now
441 		 * and let's try again once that's done.
442 		 */
443 		spin_unlock_irq(&card->lock);
444 		goto out;
445 	} else if (root_device_is_cmc) {
446 		/*
447 		 * We will send out a force root packet for this
448 		 * node as part of the gap count optimization.
449 		 */
450 		new_root_id = root_id;
451 	} else {
452 		/*
453 		 * Current root has an active link layer and we
454 		 * successfully read the config rom, but it's not
455 		 * cycle master capable.
456 		 */
457 		new_root_id = local_id;
458 	}
459 
460  pick_me:
461 	/*
462 	 * Pick a gap count from 1394a table E-1.  The table doesn't cover
463 	 * the typically much larger 1394b beta repeater delays though.
464 	 */
465 	if (!card->beta_repeaters_present &&
466 	    root_node->max_hops < ARRAY_SIZE(gap_count_table))
467 		gap_count = gap_count_table[root_node->max_hops];
468 	else
469 		gap_count = 63;
470 
471 	/*
472 	 * Finally, figure out if we should do a reset or not.  If we have
473 	 * done less than 5 resets with the same physical topology and we
474 	 * have either a new root or a new gap count setting, let's do it.
475 	 */
476 
477 	if (card->bm_retries++ < 5 &&
478 	    (card->gap_count != gap_count || new_root_id != root_id))
479 		do_reset = true;
480 
481 	spin_unlock_irq(&card->lock);
482 
483 	if (do_reset) {
484 		fw_notice(card, "phy config: new root=%x, gap_count=%d\n",
485 			  new_root_id, gap_count);
486 		fw_send_phy_config(card, new_root_id, generation, gap_count);
487 		reset_bus(card, true);
488 		/* Will allocate broadcast channel after the reset. */
489 		goto out;
490 	}
491 
492 	if (root_device_is_cmc) {
493 		/*
494 		 * Make sure that the cycle master sends cycle start packets.
495 		 */
496 		transaction_data[0] = cpu_to_be32(CSR_STATE_BIT_CMSTR);
497 		rcode = fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
498 				root_id, generation, SCODE_100,
499 				CSR_REGISTER_BASE + CSR_STATE_SET,
500 				transaction_data, 4);
501 		if (rcode == RCODE_GENERATION)
502 			goto out;
503 	}
504 
505 	if (local_id == irm_id)
506 		allocate_broadcast_channel(card, generation);
507 
508  out:
509 	fw_node_put(root_node);
510  out_put_card:
511 	fw_card_put(card);
512 }
513 
fw_card_initialize(struct fw_card * card,const struct fw_card_driver * driver,struct device * device)514 void fw_card_initialize(struct fw_card *card,
515 			const struct fw_card_driver *driver,
516 			struct device *device)
517 {
518 	static atomic_t index = ATOMIC_INIT(-1);
519 
520 	card->index = atomic_inc_return(&index);
521 	card->driver = driver;
522 	card->device = device;
523 	card->current_tlabel = 0;
524 	card->tlabel_mask = 0;
525 	card->split_timeout_hi = DEFAULT_SPLIT_TIMEOUT / 8000;
526 	card->split_timeout_lo = (DEFAULT_SPLIT_TIMEOUT % 8000) << 19;
527 	card->split_timeout_cycles = DEFAULT_SPLIT_TIMEOUT;
528 	card->split_timeout_jiffies =
529 			DIV_ROUND_UP(DEFAULT_SPLIT_TIMEOUT * HZ, 8000);
530 	card->color = 0;
531 	card->broadcast_channel = BROADCAST_CHANNEL_INITIAL;
532 
533 	kref_init(&card->kref);
534 	init_completion(&card->done);
535 	INIT_LIST_HEAD(&card->transaction_list);
536 	INIT_LIST_HEAD(&card->phy_receiver_list);
537 	spin_lock_init(&card->lock);
538 
539 	card->local_node = NULL;
540 
541 	INIT_DELAYED_WORK(&card->br_work, br_work);
542 	INIT_DELAYED_WORK(&card->bm_work, bm_work);
543 }
544 EXPORT_SYMBOL(fw_card_initialize);
545 
fw_card_add(struct fw_card * card,u32 max_receive,u32 link_speed,u64 guid)546 int fw_card_add(struct fw_card *card,
547 		u32 max_receive, u32 link_speed, u64 guid)
548 {
549 	int ret;
550 
551 	card->max_receive = max_receive;
552 	card->link_speed = link_speed;
553 	card->guid = guid;
554 
555 	mutex_lock(&card_mutex);
556 
557 	generate_config_rom(card, tmp_config_rom);
558 	ret = card->driver->enable(card, tmp_config_rom, config_rom_length);
559 	if (ret == 0)
560 		list_add_tail(&card->link, &card_list);
561 
562 	mutex_unlock(&card_mutex);
563 
564 	return ret;
565 }
566 EXPORT_SYMBOL(fw_card_add);
567 
568 /*
569  * The next few functions implement a dummy driver that is used once a card
570  * driver shuts down an fw_card.  This allows the driver to cleanly unload,
571  * as all IO to the card will be handled (and failed) by the dummy driver
572  * instead of calling into the module.  Only functions for iso context
573  * shutdown still need to be provided by the card driver.
574  *
575  * .read/write_csr() should never be called anymore after the dummy driver
576  * was bound since they are only used within request handler context.
577  * .set_config_rom() is never called since the card is taken out of card_list
578  * before switching to the dummy driver.
579  */
580 
dummy_read_phy_reg(struct fw_card * card,int address)581 static int dummy_read_phy_reg(struct fw_card *card, int address)
582 {
583 	return -ENODEV;
584 }
585 
dummy_update_phy_reg(struct fw_card * card,int address,int clear_bits,int set_bits)586 static int dummy_update_phy_reg(struct fw_card *card, int address,
587 				int clear_bits, int set_bits)
588 {
589 	return -ENODEV;
590 }
591 
dummy_send_request(struct fw_card * card,struct fw_packet * packet)592 static void dummy_send_request(struct fw_card *card, struct fw_packet *packet)
593 {
594 	packet->callback(packet, card, RCODE_CANCELLED);
595 }
596 
dummy_send_response(struct fw_card * card,struct fw_packet * packet)597 static void dummy_send_response(struct fw_card *card, struct fw_packet *packet)
598 {
599 	packet->callback(packet, card, RCODE_CANCELLED);
600 }
601 
dummy_cancel_packet(struct fw_card * card,struct fw_packet * packet)602 static int dummy_cancel_packet(struct fw_card *card, struct fw_packet *packet)
603 {
604 	return -ENOENT;
605 }
606 
dummy_enable_phys_dma(struct fw_card * card,int node_id,int generation)607 static int dummy_enable_phys_dma(struct fw_card *card,
608 				 int node_id, int generation)
609 {
610 	return -ENODEV;
611 }
612 
dummy_allocate_iso_context(struct fw_card * card,int type,int channel,size_t header_size)613 static struct fw_iso_context *dummy_allocate_iso_context(struct fw_card *card,
614 				int type, int channel, size_t header_size)
615 {
616 	return ERR_PTR(-ENODEV);
617 }
618 
dummy_read_csr(struct fw_card * card,int csr_offset)619 static u32 dummy_read_csr(struct fw_card *card, int csr_offset)
620 {
621 	return 0;
622 }
623 
dummy_write_csr(struct fw_card * card,int csr_offset,u32 value)624 static void dummy_write_csr(struct fw_card *card, int csr_offset, u32 value)
625 {
626 }
627 
dummy_start_iso(struct fw_iso_context * ctx,s32 cycle,u32 sync,u32 tags)628 static int dummy_start_iso(struct fw_iso_context *ctx,
629 			   s32 cycle, u32 sync, u32 tags)
630 {
631 	return -ENODEV;
632 }
633 
dummy_set_iso_channels(struct fw_iso_context * ctx,u64 * channels)634 static int dummy_set_iso_channels(struct fw_iso_context *ctx, u64 *channels)
635 {
636 	return -ENODEV;
637 }
638 
dummy_queue_iso(struct fw_iso_context * ctx,struct fw_iso_packet * p,struct fw_iso_buffer * buffer,unsigned long payload)639 static int dummy_queue_iso(struct fw_iso_context *ctx, struct fw_iso_packet *p,
640 			   struct fw_iso_buffer *buffer, unsigned long payload)
641 {
642 	return -ENODEV;
643 }
644 
dummy_flush_queue_iso(struct fw_iso_context * ctx)645 static void dummy_flush_queue_iso(struct fw_iso_context *ctx)
646 {
647 }
648 
dummy_flush_iso_completions(struct fw_iso_context * ctx)649 static int dummy_flush_iso_completions(struct fw_iso_context *ctx)
650 {
651 	return -ENODEV;
652 }
653 
654 static const struct fw_card_driver dummy_driver_template = {
655 	.read_phy_reg		= dummy_read_phy_reg,
656 	.update_phy_reg		= dummy_update_phy_reg,
657 	.send_request		= dummy_send_request,
658 	.send_response		= dummy_send_response,
659 	.cancel_packet		= dummy_cancel_packet,
660 	.enable_phys_dma	= dummy_enable_phys_dma,
661 	.read_csr		= dummy_read_csr,
662 	.write_csr		= dummy_write_csr,
663 	.allocate_iso_context	= dummy_allocate_iso_context,
664 	.start_iso		= dummy_start_iso,
665 	.set_iso_channels	= dummy_set_iso_channels,
666 	.queue_iso		= dummy_queue_iso,
667 	.flush_queue_iso	= dummy_flush_queue_iso,
668 	.flush_iso_completions	= dummy_flush_iso_completions,
669 };
670 
fw_card_release(struct kref * kref)671 void fw_card_release(struct kref *kref)
672 {
673 	struct fw_card *card = container_of(kref, struct fw_card, kref);
674 
675 	complete(&card->done);
676 }
677 EXPORT_SYMBOL_GPL(fw_card_release);
678 
fw_core_remove_card(struct fw_card * card)679 void fw_core_remove_card(struct fw_card *card)
680 {
681 	struct fw_card_driver dummy_driver = dummy_driver_template;
682 	unsigned long flags;
683 
684 	card->driver->update_phy_reg(card, 4,
685 				     PHY_LINK_ACTIVE | PHY_CONTENDER, 0);
686 	fw_schedule_bus_reset(card, false, true);
687 
688 	mutex_lock(&card_mutex);
689 	list_del_init(&card->link);
690 	mutex_unlock(&card_mutex);
691 
692 	/* Switch off most of the card driver interface. */
693 	dummy_driver.free_iso_context	= card->driver->free_iso_context;
694 	dummy_driver.stop_iso		= card->driver->stop_iso;
695 	card->driver = &dummy_driver;
696 
697 	spin_lock_irqsave(&card->lock, flags);
698 	fw_destroy_nodes(card);
699 	spin_unlock_irqrestore(&card->lock, flags);
700 
701 	/* Wait for all users, especially device workqueue jobs, to finish. */
702 	fw_card_put(card);
703 	wait_for_completion(&card->done);
704 
705 	WARN_ON(!list_empty(&card->transaction_list));
706 }
707 EXPORT_SYMBOL(fw_core_remove_card);
708 
709 /**
710  * fw_card_read_cycle_time: read from Isochronous Cycle Timer Register of 1394 OHCI in MMIO region
711  *			    for controller card.
712  * @card: The instance of card for 1394 OHCI controller.
713  * @cycle_time: The mutual reference to value of cycle time for the read operation.
714  *
715  * Read value from Isochronous Cycle Timer Register of 1394 OHCI in MMIO region for the given
716  * controller card. This function accesses the region without any lock primitives or IRQ mask.
717  * When returning successfully, the content of @value argument has value aligned to host endianness,
718  * formetted by CYCLE_TIME CSR Register of IEEE 1394 std.
719  *
720  * Context: Any context.
721  * Return:
722  * * 0 - Read successfully.
723  * * -ENODEV - The controller is unavailable due to being removed or unbound.
724  */
fw_card_read_cycle_time(struct fw_card * card,u32 * cycle_time)725 int fw_card_read_cycle_time(struct fw_card *card, u32 *cycle_time)
726 {
727 	if (card->driver->read_csr == dummy_read_csr)
728 		return -ENODEV;
729 
730 	// It's possible to switch to dummy driver between the above and the below. This is the best
731 	// effort to return -ENODEV.
732 	*cycle_time = card->driver->read_csr(card, CSR_CYCLE_TIME);
733 	return 0;
734 }
735 EXPORT_SYMBOL_GPL(fw_card_read_cycle_time);
736