1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Device probing and sysfs code.
4  *
5  * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
6  */
7 
8 #include <linux/bug.h>
9 #include <linux/ctype.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/errno.h>
13 #include <linux/firewire.h>
14 #include <linux/firewire-constants.h>
15 #include <linux/idr.h>
16 #include <linux/jiffies.h>
17 #include <linux/kobject.h>
18 #include <linux/list.h>
19 #include <linux/mod_devicetable.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/random.h>
23 #include <linux/rwsem.h>
24 #include <linux/slab.h>
25 #include <linux/spinlock.h>
26 #include <linux/string.h>
27 #include <linux/workqueue.h>
28 
29 #include <linux/atomic.h>
30 #include <asm/byteorder.h>
31 
32 #include "core.h"
33 
34 void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p)
35 {
36 	ci->p = p + 1;
37 	ci->end = ci->p + (p[0] >> 16);
38 }
39 EXPORT_SYMBOL(fw_csr_iterator_init);
40 
41 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
42 {
43 	*key = *ci->p >> 24;
44 	*value = *ci->p & 0xffffff;
45 
46 	return ci->p++ < ci->end;
47 }
48 EXPORT_SYMBOL(fw_csr_iterator_next);
49 
50 static const u32 *search_leaf(const u32 *directory, int search_key)
51 {
52 	struct fw_csr_iterator ci;
53 	int last_key = 0, key, value;
54 
55 	fw_csr_iterator_init(&ci, directory);
56 	while (fw_csr_iterator_next(&ci, &key, &value)) {
57 		if (last_key == search_key &&
58 		    key == (CSR_DESCRIPTOR | CSR_LEAF))
59 			return ci.p - 1 + value;
60 
61 		last_key = key;
62 	}
63 
64 	return NULL;
65 }
66 
67 static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
68 {
69 	unsigned int quadlets, i;
70 	char c;
71 
72 	if (!size || !buf)
73 		return -EINVAL;
74 
75 	quadlets = min(block[0] >> 16, 256U);
76 	if (quadlets < 2)
77 		return -ENODATA;
78 
79 	if (block[1] != 0 || block[2] != 0)
80 		/* unknown language/character set */
81 		return -ENODATA;
82 
83 	block += 3;
84 	quadlets -= 2;
85 	for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
86 		c = block[i / 4] >> (24 - 8 * (i % 4));
87 		if (c == '\0')
88 			break;
89 		buf[i] = c;
90 	}
91 	buf[i] = '\0';
92 
93 	return i;
94 }
95 
96 /**
97  * fw_csr_string() - reads a string from the configuration ROM
98  * @directory:	e.g. root directory or unit directory
99  * @key:	the key of the preceding directory entry
100  * @buf:	where to put the string
101  * @size:	size of @buf, in bytes
102  *
103  * The string is taken from a minimal ASCII text descriptor leaf after
104  * the immediate entry with @key.  The string is zero-terminated.
105  * An overlong string is silently truncated such that it and the
106  * zero byte fit into @size.
107  *
108  * Returns strlen(buf) or a negative error code.
109  */
110 int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
111 {
112 	const u32 *leaf = search_leaf(directory, key);
113 	if (!leaf)
114 		return -ENOENT;
115 
116 	return textual_leaf_to_string(leaf, buf, size);
117 }
118 EXPORT_SYMBOL(fw_csr_string);
119 
120 static void get_ids(const u32 *directory, int *id)
121 {
122 	struct fw_csr_iterator ci;
123 	int key, value;
124 
125 	fw_csr_iterator_init(&ci, directory);
126 	while (fw_csr_iterator_next(&ci, &key, &value)) {
127 		switch (key) {
128 		case CSR_VENDOR:	id[0] = value; break;
129 		case CSR_MODEL:		id[1] = value; break;
130 		case CSR_SPECIFIER_ID:	id[2] = value; break;
131 		case CSR_VERSION:	id[3] = value; break;
132 		}
133 	}
134 }
135 
136 static void get_modalias_ids(const struct fw_unit *unit, int *id)
137 {
138 	get_ids(&fw_parent_device(unit)->config_rom[5], id);
139 	get_ids(unit->directory, id);
140 }
141 
142 static bool match_ids(const struct ieee1394_device_id *id_table, int *id)
143 {
144 	int match = 0;
145 
146 	if (id[0] == id_table->vendor_id)
147 		match |= IEEE1394_MATCH_VENDOR_ID;
148 	if (id[1] == id_table->model_id)
149 		match |= IEEE1394_MATCH_MODEL_ID;
150 	if (id[2] == id_table->specifier_id)
151 		match |= IEEE1394_MATCH_SPECIFIER_ID;
152 	if (id[3] == id_table->version)
153 		match |= IEEE1394_MATCH_VERSION;
154 
155 	return (match & id_table->match_flags) == id_table->match_flags;
156 }
157 
158 static const struct ieee1394_device_id *unit_match(struct device *dev,
159 						   struct device_driver *drv)
160 {
161 	const struct ieee1394_device_id *id_table =
162 			container_of(drv, struct fw_driver, driver)->id_table;
163 	int id[] = {0, 0, 0, 0};
164 
165 	get_modalias_ids(fw_unit(dev), id);
166 
167 	for (; id_table->match_flags != 0; id_table++)
168 		if (match_ids(id_table, id))
169 			return id_table;
170 
171 	return NULL;
172 }
173 
174 static bool is_fw_unit(struct device *dev);
175 
176 static int fw_unit_match(struct device *dev, struct device_driver *drv)
177 {
178 	/* We only allow binding to fw_units. */
179 	return is_fw_unit(dev) && unit_match(dev, drv) != NULL;
180 }
181 
182 static int fw_unit_probe(struct device *dev)
183 {
184 	struct fw_driver *driver =
185 			container_of(dev->driver, struct fw_driver, driver);
186 
187 	return driver->probe(fw_unit(dev), unit_match(dev, dev->driver));
188 }
189 
190 static void fw_unit_remove(struct device *dev)
191 {
192 	struct fw_driver *driver =
193 			container_of(dev->driver, struct fw_driver, driver);
194 
195 	driver->remove(fw_unit(dev));
196 }
197 
198 static int get_modalias(const struct fw_unit *unit, char *buffer, size_t buffer_size)
199 {
200 	int id[] = {0, 0, 0, 0};
201 
202 	get_modalias_ids(unit, id);
203 
204 	return snprintf(buffer, buffer_size,
205 			"ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
206 			id[0], id[1], id[2], id[3]);
207 }
208 
209 static int fw_unit_uevent(const struct device *dev, struct kobj_uevent_env *env)
210 {
211 	const struct fw_unit *unit = fw_unit(dev);
212 	char modalias[64];
213 
214 	get_modalias(unit, modalias, sizeof(modalias));
215 
216 	if (add_uevent_var(env, "MODALIAS=%s", modalias))
217 		return -ENOMEM;
218 
219 	return 0;
220 }
221 
222 struct bus_type fw_bus_type = {
223 	.name = "firewire",
224 	.match = fw_unit_match,
225 	.probe = fw_unit_probe,
226 	.remove = fw_unit_remove,
227 };
228 EXPORT_SYMBOL(fw_bus_type);
229 
230 int fw_device_enable_phys_dma(struct fw_device *device)
231 {
232 	int generation = device->generation;
233 
234 	/* device->node_id, accessed below, must not be older than generation */
235 	smp_rmb();
236 
237 	return device->card->driver->enable_phys_dma(device->card,
238 						     device->node_id,
239 						     generation);
240 }
241 EXPORT_SYMBOL(fw_device_enable_phys_dma);
242 
243 struct config_rom_attribute {
244 	struct device_attribute attr;
245 	u32 key;
246 };
247 
248 static ssize_t show_immediate(struct device *dev,
249 			      struct device_attribute *dattr, char *buf)
250 {
251 	struct config_rom_attribute *attr =
252 		container_of(dattr, struct config_rom_attribute, attr);
253 	struct fw_csr_iterator ci;
254 	const u32 *dir;
255 	int key, value, ret = -ENOENT;
256 
257 	down_read(&fw_device_rwsem);
258 
259 	if (is_fw_unit(dev))
260 		dir = fw_unit(dev)->directory;
261 	else
262 		dir = fw_device(dev)->config_rom + 5;
263 
264 	fw_csr_iterator_init(&ci, dir);
265 	while (fw_csr_iterator_next(&ci, &key, &value))
266 		if (attr->key == key) {
267 			ret = snprintf(buf, buf ? PAGE_SIZE : 0,
268 				       "0x%06x\n", value);
269 			break;
270 		}
271 
272 	up_read(&fw_device_rwsem);
273 
274 	return ret;
275 }
276 
277 #define IMMEDIATE_ATTR(name, key)				\
278 	{ __ATTR(name, S_IRUGO, show_immediate, NULL), key }
279 
280 static ssize_t show_text_leaf(struct device *dev,
281 			      struct device_attribute *dattr, char *buf)
282 {
283 	struct config_rom_attribute *attr =
284 		container_of(dattr, struct config_rom_attribute, attr);
285 	const u32 *dir;
286 	size_t bufsize;
287 	char dummy_buf[2];
288 	int ret;
289 
290 	down_read(&fw_device_rwsem);
291 
292 	if (is_fw_unit(dev))
293 		dir = fw_unit(dev)->directory;
294 	else
295 		dir = fw_device(dev)->config_rom + 5;
296 
297 	if (buf) {
298 		bufsize = PAGE_SIZE - 1;
299 	} else {
300 		buf = dummy_buf;
301 		bufsize = 1;
302 	}
303 
304 	ret = fw_csr_string(dir, attr->key, buf, bufsize);
305 
306 	if (ret >= 0) {
307 		/* Strip trailing whitespace and add newline. */
308 		while (ret > 0 && isspace(buf[ret - 1]))
309 			ret--;
310 		strcpy(buf + ret, "\n");
311 		ret++;
312 	}
313 
314 	up_read(&fw_device_rwsem);
315 
316 	return ret;
317 }
318 
319 #define TEXT_LEAF_ATTR(name, key)				\
320 	{ __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
321 
322 static struct config_rom_attribute config_rom_attributes[] = {
323 	IMMEDIATE_ATTR(vendor, CSR_VENDOR),
324 	IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
325 	IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
326 	IMMEDIATE_ATTR(version, CSR_VERSION),
327 	IMMEDIATE_ATTR(model, CSR_MODEL),
328 	TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
329 	TEXT_LEAF_ATTR(model_name, CSR_MODEL),
330 	TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
331 };
332 
333 static void init_fw_attribute_group(struct device *dev,
334 				    struct device_attribute *attrs,
335 				    struct fw_attribute_group *group)
336 {
337 	struct device_attribute *attr;
338 	int i, j;
339 
340 	for (j = 0; attrs[j].attr.name != NULL; j++)
341 		group->attrs[j] = &attrs[j].attr;
342 
343 	for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
344 		attr = &config_rom_attributes[i].attr;
345 		if (attr->show(dev, attr, NULL) < 0)
346 			continue;
347 		group->attrs[j++] = &attr->attr;
348 	}
349 
350 	group->attrs[j] = NULL;
351 	group->groups[0] = &group->group;
352 	group->groups[1] = NULL;
353 	group->group.attrs = group->attrs;
354 	dev->groups = (const struct attribute_group **) group->groups;
355 }
356 
357 static ssize_t modalias_show(struct device *dev,
358 			     struct device_attribute *attr, char *buf)
359 {
360 	struct fw_unit *unit = fw_unit(dev);
361 	int length;
362 
363 	length = get_modalias(unit, buf, PAGE_SIZE);
364 	strcpy(buf + length, "\n");
365 
366 	return length + 1;
367 }
368 
369 static ssize_t rom_index_show(struct device *dev,
370 			      struct device_attribute *attr, char *buf)
371 {
372 	struct fw_device *device = fw_device(dev->parent);
373 	struct fw_unit *unit = fw_unit(dev);
374 
375 	return sysfs_emit(buf, "%td\n", unit->directory - device->config_rom);
376 }
377 
378 static struct device_attribute fw_unit_attributes[] = {
379 	__ATTR_RO(modalias),
380 	__ATTR_RO(rom_index),
381 	__ATTR_NULL,
382 };
383 
384 static ssize_t config_rom_show(struct device *dev,
385 			       struct device_attribute *attr, char *buf)
386 {
387 	struct fw_device *device = fw_device(dev);
388 	size_t length;
389 
390 	down_read(&fw_device_rwsem);
391 	length = device->config_rom_length * 4;
392 	memcpy(buf, device->config_rom, length);
393 	up_read(&fw_device_rwsem);
394 
395 	return length;
396 }
397 
398 static ssize_t guid_show(struct device *dev,
399 			 struct device_attribute *attr, char *buf)
400 {
401 	struct fw_device *device = fw_device(dev);
402 	int ret;
403 
404 	down_read(&fw_device_rwsem);
405 	ret = sysfs_emit(buf, "0x%08x%08x\n", device->config_rom[3], device->config_rom[4]);
406 	up_read(&fw_device_rwsem);
407 
408 	return ret;
409 }
410 
411 static ssize_t is_local_show(struct device *dev,
412 			     struct device_attribute *attr, char *buf)
413 {
414 	struct fw_device *device = fw_device(dev);
415 
416 	return sprintf(buf, "%u\n", device->is_local);
417 }
418 
419 static int units_sprintf(char *buf, const u32 *directory)
420 {
421 	struct fw_csr_iterator ci;
422 	int key, value;
423 	int specifier_id = 0;
424 	int version = 0;
425 
426 	fw_csr_iterator_init(&ci, directory);
427 	while (fw_csr_iterator_next(&ci, &key, &value)) {
428 		switch (key) {
429 		case CSR_SPECIFIER_ID:
430 			specifier_id = value;
431 			break;
432 		case CSR_VERSION:
433 			version = value;
434 			break;
435 		}
436 	}
437 
438 	return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
439 }
440 
441 static ssize_t units_show(struct device *dev,
442 			  struct device_attribute *attr, char *buf)
443 {
444 	struct fw_device *device = fw_device(dev);
445 	struct fw_csr_iterator ci;
446 	int key, value, i = 0;
447 
448 	down_read(&fw_device_rwsem);
449 	fw_csr_iterator_init(&ci, &device->config_rom[5]);
450 	while (fw_csr_iterator_next(&ci, &key, &value)) {
451 		if (key != (CSR_UNIT | CSR_DIRECTORY))
452 			continue;
453 		i += units_sprintf(&buf[i], ci.p + value - 1);
454 		if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
455 			break;
456 	}
457 	up_read(&fw_device_rwsem);
458 
459 	if (i)
460 		buf[i - 1] = '\n';
461 
462 	return i;
463 }
464 
465 static struct device_attribute fw_device_attributes[] = {
466 	__ATTR_RO(config_rom),
467 	__ATTR_RO(guid),
468 	__ATTR_RO(is_local),
469 	__ATTR_RO(units),
470 	__ATTR_NULL,
471 };
472 
473 static int read_rom(struct fw_device *device,
474 		    int generation, int index, u32 *data)
475 {
476 	u64 offset = (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4;
477 	int i, rcode;
478 
479 	/* device->node_id, accessed below, must not be older than generation */
480 	smp_rmb();
481 
482 	for (i = 10; i < 100; i += 10) {
483 		rcode = fw_run_transaction(device->card,
484 				TCODE_READ_QUADLET_REQUEST, device->node_id,
485 				generation, device->max_speed, offset, data, 4);
486 		if (rcode != RCODE_BUSY)
487 			break;
488 		msleep(i);
489 	}
490 	be32_to_cpus(data);
491 
492 	return rcode;
493 }
494 
495 #define MAX_CONFIG_ROM_SIZE 256
496 
497 /*
498  * Read the bus info block, perform a speed probe, and read all of the rest of
499  * the config ROM.  We do all this with a cached bus generation.  If the bus
500  * generation changes under us, read_config_rom will fail and get retried.
501  * It's better to start all over in this case because the node from which we
502  * are reading the ROM may have changed the ROM during the reset.
503  * Returns either a result code or a negative error code.
504  */
505 static int read_config_rom(struct fw_device *device, int generation)
506 {
507 	struct fw_card *card = device->card;
508 	const u32 *old_rom, *new_rom;
509 	u32 *rom, *stack;
510 	u32 sp, key;
511 	int i, end, length, ret;
512 
513 	rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
514 		      sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
515 	if (rom == NULL)
516 		return -ENOMEM;
517 
518 	stack = &rom[MAX_CONFIG_ROM_SIZE];
519 	memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
520 
521 	device->max_speed = SCODE_100;
522 
523 	/* First read the bus info block. */
524 	for (i = 0; i < 5; i++) {
525 		ret = read_rom(device, generation, i, &rom[i]);
526 		if (ret != RCODE_COMPLETE)
527 			goto out;
528 		/*
529 		 * As per IEEE1212 7.2, during initialization, devices can
530 		 * reply with a 0 for the first quadlet of the config
531 		 * rom to indicate that they are booting (for example,
532 		 * if the firmware is on the disk of a external
533 		 * harddisk).  In that case we just fail, and the
534 		 * retry mechanism will try again later.
535 		 */
536 		if (i == 0 && rom[i] == 0) {
537 			ret = RCODE_BUSY;
538 			goto out;
539 		}
540 	}
541 
542 	device->max_speed = device->node->max_speed;
543 
544 	/*
545 	 * Determine the speed of
546 	 *   - devices with link speed less than PHY speed,
547 	 *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
548 	 *   - all devices if there are 1394b repeaters.
549 	 * Note, we cannot use the bus info block's link_spd as starting point
550 	 * because some buggy firmwares set it lower than necessary and because
551 	 * 1394-1995 nodes do not have the field.
552 	 */
553 	if ((rom[2] & 0x7) < device->max_speed ||
554 	    device->max_speed == SCODE_BETA ||
555 	    card->beta_repeaters_present) {
556 		u32 dummy;
557 
558 		/* for S1600 and S3200 */
559 		if (device->max_speed == SCODE_BETA)
560 			device->max_speed = card->link_speed;
561 
562 		while (device->max_speed > SCODE_100) {
563 			if (read_rom(device, generation, 0, &dummy) ==
564 			    RCODE_COMPLETE)
565 				break;
566 			device->max_speed--;
567 		}
568 	}
569 
570 	/*
571 	 * Now parse the config rom.  The config rom is a recursive
572 	 * directory structure so we parse it using a stack of
573 	 * references to the blocks that make up the structure.  We
574 	 * push a reference to the root directory on the stack to
575 	 * start things off.
576 	 */
577 	length = i;
578 	sp = 0;
579 	stack[sp++] = 0xc0000005;
580 	while (sp > 0) {
581 		/*
582 		 * Pop the next block reference of the stack.  The
583 		 * lower 24 bits is the offset into the config rom,
584 		 * the upper 8 bits are the type of the reference the
585 		 * block.
586 		 */
587 		key = stack[--sp];
588 		i = key & 0xffffff;
589 		if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE)) {
590 			ret = -ENXIO;
591 			goto out;
592 		}
593 
594 		/* Read header quadlet for the block to get the length. */
595 		ret = read_rom(device, generation, i, &rom[i]);
596 		if (ret != RCODE_COMPLETE)
597 			goto out;
598 		end = i + (rom[i] >> 16) + 1;
599 		if (end > MAX_CONFIG_ROM_SIZE) {
600 			/*
601 			 * This block extends outside the config ROM which is
602 			 * a firmware bug.  Ignore this whole block, i.e.
603 			 * simply set a fake block length of 0.
604 			 */
605 			fw_err(card, "skipped invalid ROM block %x at %llx\n",
606 			       rom[i],
607 			       i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
608 			rom[i] = 0;
609 			end = i;
610 		}
611 		i++;
612 
613 		/*
614 		 * Now read in the block.  If this is a directory
615 		 * block, check the entries as we read them to see if
616 		 * it references another block, and push it in that case.
617 		 */
618 		for (; i < end; i++) {
619 			ret = read_rom(device, generation, i, &rom[i]);
620 			if (ret != RCODE_COMPLETE)
621 				goto out;
622 
623 			if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
624 				continue;
625 			/*
626 			 * Offset points outside the ROM.  May be a firmware
627 			 * bug or an Extended ROM entry (IEEE 1212-2001 clause
628 			 * 7.7.18).  Simply overwrite this pointer here by a
629 			 * fake immediate entry so that later iterators over
630 			 * the ROM don't have to check offsets all the time.
631 			 */
632 			if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
633 				fw_err(card,
634 				       "skipped unsupported ROM entry %x at %llx\n",
635 				       rom[i],
636 				       i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
637 				rom[i] = 0;
638 				continue;
639 			}
640 			stack[sp++] = i + rom[i];
641 		}
642 		if (length < i)
643 			length = i;
644 	}
645 
646 	old_rom = device->config_rom;
647 	new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
648 	if (new_rom == NULL) {
649 		ret = -ENOMEM;
650 		goto out;
651 	}
652 
653 	down_write(&fw_device_rwsem);
654 	device->config_rom = new_rom;
655 	device->config_rom_length = length;
656 	up_write(&fw_device_rwsem);
657 
658 	kfree(old_rom);
659 	ret = RCODE_COMPLETE;
660 	device->max_rec	= rom[2] >> 12 & 0xf;
661 	device->cmc	= rom[2] >> 30 & 1;
662 	device->irmc	= rom[2] >> 31 & 1;
663  out:
664 	kfree(rom);
665 
666 	return ret;
667 }
668 
669 static void fw_unit_release(struct device *dev)
670 {
671 	struct fw_unit *unit = fw_unit(dev);
672 
673 	fw_device_put(fw_parent_device(unit));
674 	kfree(unit);
675 }
676 
677 static struct device_type fw_unit_type = {
678 	.uevent		= fw_unit_uevent,
679 	.release	= fw_unit_release,
680 };
681 
682 static bool is_fw_unit(struct device *dev)
683 {
684 	return dev->type == &fw_unit_type;
685 }
686 
687 static void create_units(struct fw_device *device)
688 {
689 	struct fw_csr_iterator ci;
690 	struct fw_unit *unit;
691 	int key, value, i;
692 
693 	i = 0;
694 	fw_csr_iterator_init(&ci, &device->config_rom[5]);
695 	while (fw_csr_iterator_next(&ci, &key, &value)) {
696 		if (key != (CSR_UNIT | CSR_DIRECTORY))
697 			continue;
698 
699 		/*
700 		 * Get the address of the unit directory and try to
701 		 * match the drivers id_tables against it.
702 		 */
703 		unit = kzalloc(sizeof(*unit), GFP_KERNEL);
704 		if (unit == NULL)
705 			continue;
706 
707 		unit->directory = ci.p + value - 1;
708 		unit->device.bus = &fw_bus_type;
709 		unit->device.type = &fw_unit_type;
710 		unit->device.parent = &device->device;
711 		dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
712 
713 		BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
714 				ARRAY_SIZE(fw_unit_attributes) +
715 				ARRAY_SIZE(config_rom_attributes));
716 		init_fw_attribute_group(&unit->device,
717 					fw_unit_attributes,
718 					&unit->attribute_group);
719 
720 		if (device_register(&unit->device) < 0)
721 			goto skip_unit;
722 
723 		fw_device_get(device);
724 		continue;
725 
726 	skip_unit:
727 		kfree(unit);
728 	}
729 }
730 
731 static int shutdown_unit(struct device *device, void *data)
732 {
733 	device_unregister(device);
734 
735 	return 0;
736 }
737 
738 /*
739  * fw_device_rwsem acts as dual purpose mutex:
740  *   - serializes accesses to fw_device_idr,
741  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
742  *     fw_unit.directory, unless those accesses happen at safe occasions
743  */
744 DECLARE_RWSEM(fw_device_rwsem);
745 
746 DEFINE_IDR(fw_device_idr);
747 int fw_cdev_major;
748 
749 struct fw_device *fw_device_get_by_devt(dev_t devt)
750 {
751 	struct fw_device *device;
752 
753 	down_read(&fw_device_rwsem);
754 	device = idr_find(&fw_device_idr, MINOR(devt));
755 	if (device)
756 		fw_device_get(device);
757 	up_read(&fw_device_rwsem);
758 
759 	return device;
760 }
761 
762 struct workqueue_struct *fw_workqueue;
763 EXPORT_SYMBOL(fw_workqueue);
764 
765 static void fw_schedule_device_work(struct fw_device *device,
766 				    unsigned long delay)
767 {
768 	queue_delayed_work(fw_workqueue, &device->work, delay);
769 }
770 
771 /*
772  * These defines control the retry behavior for reading the config
773  * rom.  It shouldn't be necessary to tweak these; if the device
774  * doesn't respond to a config rom read within 10 seconds, it's not
775  * going to respond at all.  As for the initial delay, a lot of
776  * devices will be able to respond within half a second after bus
777  * reset.  On the other hand, it's not really worth being more
778  * aggressive than that, since it scales pretty well; if 10 devices
779  * are plugged in, they're all getting read within one second.
780  */
781 
782 #define MAX_RETRIES	10
783 #define RETRY_DELAY	(3 * HZ)
784 #define INITIAL_DELAY	(HZ / 2)
785 #define SHUTDOWN_DELAY	(2 * HZ)
786 
787 static void fw_device_shutdown(struct work_struct *work)
788 {
789 	struct fw_device *device =
790 		container_of(work, struct fw_device, work.work);
791 	int minor = MINOR(device->device.devt);
792 
793 	if (time_before64(get_jiffies_64(),
794 			  device->card->reset_jiffies + SHUTDOWN_DELAY)
795 	    && !list_empty(&device->card->link)) {
796 		fw_schedule_device_work(device, SHUTDOWN_DELAY);
797 		return;
798 	}
799 
800 	if (atomic_cmpxchg(&device->state,
801 			   FW_DEVICE_GONE,
802 			   FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
803 		return;
804 
805 	fw_device_cdev_remove(device);
806 	device_for_each_child(&device->device, NULL, shutdown_unit);
807 	device_unregister(&device->device);
808 
809 	down_write(&fw_device_rwsem);
810 	idr_remove(&fw_device_idr, minor);
811 	up_write(&fw_device_rwsem);
812 
813 	fw_device_put(device);
814 }
815 
816 static void fw_device_release(struct device *dev)
817 {
818 	struct fw_device *device = fw_device(dev);
819 	struct fw_card *card = device->card;
820 	unsigned long flags;
821 
822 	/*
823 	 * Take the card lock so we don't set this to NULL while a
824 	 * FW_NODE_UPDATED callback is being handled or while the
825 	 * bus manager work looks at this node.
826 	 */
827 	spin_lock_irqsave(&card->lock, flags);
828 	device->node->data = NULL;
829 	spin_unlock_irqrestore(&card->lock, flags);
830 
831 	fw_node_put(device->node);
832 	kfree(device->config_rom);
833 	kfree(device);
834 	fw_card_put(card);
835 }
836 
837 static struct device_type fw_device_type = {
838 	.release = fw_device_release,
839 };
840 
841 static bool is_fw_device(struct device *dev)
842 {
843 	return dev->type == &fw_device_type;
844 }
845 
846 static int update_unit(struct device *dev, void *data)
847 {
848 	struct fw_unit *unit = fw_unit(dev);
849 	struct fw_driver *driver = (struct fw_driver *)dev->driver;
850 
851 	if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
852 		device_lock(dev);
853 		driver->update(unit);
854 		device_unlock(dev);
855 	}
856 
857 	return 0;
858 }
859 
860 static void fw_device_update(struct work_struct *work)
861 {
862 	struct fw_device *device =
863 		container_of(work, struct fw_device, work.work);
864 
865 	fw_device_cdev_update(device);
866 	device_for_each_child(&device->device, NULL, update_unit);
867 }
868 
869 /*
870  * If a device was pending for deletion because its node went away but its
871  * bus info block and root directory header matches that of a newly discovered
872  * device, revive the existing fw_device.
873  * The newly allocated fw_device becomes obsolete instead.
874  */
875 static int lookup_existing_device(struct device *dev, void *data)
876 {
877 	struct fw_device *old = fw_device(dev);
878 	struct fw_device *new = data;
879 	struct fw_card *card = new->card;
880 	int match = 0;
881 
882 	if (!is_fw_device(dev))
883 		return 0;
884 
885 	down_read(&fw_device_rwsem); /* serialize config_rom access */
886 	spin_lock_irq(&card->lock);  /* serialize node access */
887 
888 	if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
889 	    atomic_cmpxchg(&old->state,
890 			   FW_DEVICE_GONE,
891 			   FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
892 		struct fw_node *current_node = new->node;
893 		struct fw_node *obsolete_node = old->node;
894 
895 		new->node = obsolete_node;
896 		new->node->data = new;
897 		old->node = current_node;
898 		old->node->data = old;
899 
900 		old->max_speed = new->max_speed;
901 		old->node_id = current_node->node_id;
902 		smp_wmb();  /* update node_id before generation */
903 		old->generation = card->generation;
904 		old->config_rom_retries = 0;
905 		fw_notice(card, "rediscovered device %s\n", dev_name(dev));
906 
907 		old->workfn = fw_device_update;
908 		fw_schedule_device_work(old, 0);
909 
910 		if (current_node == card->root_node)
911 			fw_schedule_bm_work(card, 0);
912 
913 		match = 1;
914 	}
915 
916 	spin_unlock_irq(&card->lock);
917 	up_read(&fw_device_rwsem);
918 
919 	return match;
920 }
921 
922 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
923 
924 static void set_broadcast_channel(struct fw_device *device, int generation)
925 {
926 	struct fw_card *card = device->card;
927 	__be32 data;
928 	int rcode;
929 
930 	if (!card->broadcast_channel_allocated)
931 		return;
932 
933 	/*
934 	 * The Broadcast_Channel Valid bit is required by nodes which want to
935 	 * transmit on this channel.  Such transmissions are practically
936 	 * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
937 	 * to be IRM capable and have a max_rec of 8 or more.  We use this fact
938 	 * to narrow down to which nodes we send Broadcast_Channel updates.
939 	 */
940 	if (!device->irmc || device->max_rec < 8)
941 		return;
942 
943 	/*
944 	 * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
945 	 * Perform a read test first.
946 	 */
947 	if (device->bc_implemented == BC_UNKNOWN) {
948 		rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
949 				device->node_id, generation, device->max_speed,
950 				CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
951 				&data, 4);
952 		switch (rcode) {
953 		case RCODE_COMPLETE:
954 			if (data & cpu_to_be32(1 << 31)) {
955 				device->bc_implemented = BC_IMPLEMENTED;
956 				break;
957 			}
958 			fallthrough;	/* to case address error */
959 		case RCODE_ADDRESS_ERROR:
960 			device->bc_implemented = BC_UNIMPLEMENTED;
961 		}
962 	}
963 
964 	if (device->bc_implemented == BC_IMPLEMENTED) {
965 		data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
966 				   BROADCAST_CHANNEL_VALID);
967 		fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
968 				device->node_id, generation, device->max_speed,
969 				CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
970 				&data, 4);
971 	}
972 }
973 
974 int fw_device_set_broadcast_channel(struct device *dev, void *gen)
975 {
976 	if (is_fw_device(dev))
977 		set_broadcast_channel(fw_device(dev), (long)gen);
978 
979 	return 0;
980 }
981 
982 static void fw_device_init(struct work_struct *work)
983 {
984 	struct fw_device *device =
985 		container_of(work, struct fw_device, work.work);
986 	struct fw_card *card = device->card;
987 	struct device *revived_dev;
988 	int minor, ret;
989 
990 	/*
991 	 * All failure paths here set node->data to NULL, so that we
992 	 * don't try to do device_for_each_child() on a kfree()'d
993 	 * device.
994 	 */
995 
996 	ret = read_config_rom(device, device->generation);
997 	if (ret != RCODE_COMPLETE) {
998 		if (device->config_rom_retries < MAX_RETRIES &&
999 		    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1000 			device->config_rom_retries++;
1001 			fw_schedule_device_work(device, RETRY_DELAY);
1002 		} else {
1003 			if (device->node->link_on)
1004 				fw_notice(card, "giving up on node %x: reading config rom failed: %s\n",
1005 					  device->node_id,
1006 					  fw_rcode_string(ret));
1007 			if (device->node == card->root_node)
1008 				fw_schedule_bm_work(card, 0);
1009 			fw_device_release(&device->device);
1010 		}
1011 		return;
1012 	}
1013 
1014 	revived_dev = device_find_child(card->device,
1015 					device, lookup_existing_device);
1016 	if (revived_dev) {
1017 		put_device(revived_dev);
1018 		fw_device_release(&device->device);
1019 
1020 		return;
1021 	}
1022 
1023 	device_initialize(&device->device);
1024 
1025 	fw_device_get(device);
1026 	down_write(&fw_device_rwsem);
1027 	minor = idr_alloc(&fw_device_idr, device, 0, 1 << MINORBITS,
1028 			GFP_KERNEL);
1029 	up_write(&fw_device_rwsem);
1030 
1031 	if (minor < 0)
1032 		goto error;
1033 
1034 	device->device.bus = &fw_bus_type;
1035 	device->device.type = &fw_device_type;
1036 	device->device.parent = card->device;
1037 	device->device.devt = MKDEV(fw_cdev_major, minor);
1038 	dev_set_name(&device->device, "fw%d", minor);
1039 
1040 	BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
1041 			ARRAY_SIZE(fw_device_attributes) +
1042 			ARRAY_SIZE(config_rom_attributes));
1043 	init_fw_attribute_group(&device->device,
1044 				fw_device_attributes,
1045 				&device->attribute_group);
1046 
1047 	if (device_add(&device->device)) {
1048 		fw_err(card, "failed to add device\n");
1049 		goto error_with_cdev;
1050 	}
1051 
1052 	create_units(device);
1053 
1054 	/*
1055 	 * Transition the device to running state.  If it got pulled
1056 	 * out from under us while we did the initialization work, we
1057 	 * have to shut down the device again here.  Normally, though,
1058 	 * fw_node_event will be responsible for shutting it down when
1059 	 * necessary.  We have to use the atomic cmpxchg here to avoid
1060 	 * racing with the FW_NODE_DESTROYED case in
1061 	 * fw_node_event().
1062 	 */
1063 	if (atomic_cmpxchg(&device->state,
1064 			   FW_DEVICE_INITIALIZING,
1065 			   FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1066 		device->workfn = fw_device_shutdown;
1067 		fw_schedule_device_work(device, SHUTDOWN_DELAY);
1068 	} else {
1069 		fw_notice(card, "created device %s: GUID %08x%08x, S%d00\n",
1070 			  dev_name(&device->device),
1071 			  device->config_rom[3], device->config_rom[4],
1072 			  1 << device->max_speed);
1073 		device->config_rom_retries = 0;
1074 
1075 		set_broadcast_channel(device, device->generation);
1076 
1077 		add_device_randomness(&device->config_rom[3], 8);
1078 	}
1079 
1080 	/*
1081 	 * Reschedule the IRM work if we just finished reading the
1082 	 * root node config rom.  If this races with a bus reset we
1083 	 * just end up running the IRM work a couple of extra times -
1084 	 * pretty harmless.
1085 	 */
1086 	if (device->node == card->root_node)
1087 		fw_schedule_bm_work(card, 0);
1088 
1089 	return;
1090 
1091  error_with_cdev:
1092 	down_write(&fw_device_rwsem);
1093 	idr_remove(&fw_device_idr, minor);
1094 	up_write(&fw_device_rwsem);
1095  error:
1096 	fw_device_put(device);		/* fw_device_idr's reference */
1097 
1098 	put_device(&device->device);	/* our reference */
1099 }
1100 
1101 /* Reread and compare bus info block and header of root directory */
1102 static int reread_config_rom(struct fw_device *device, int generation,
1103 			     bool *changed)
1104 {
1105 	u32 q;
1106 	int i, rcode;
1107 
1108 	for (i = 0; i < 6; i++) {
1109 		rcode = read_rom(device, generation, i, &q);
1110 		if (rcode != RCODE_COMPLETE)
1111 			return rcode;
1112 
1113 		if (i == 0 && q == 0)
1114 			/* inaccessible (see read_config_rom); retry later */
1115 			return RCODE_BUSY;
1116 
1117 		if (q != device->config_rom[i]) {
1118 			*changed = true;
1119 			return RCODE_COMPLETE;
1120 		}
1121 	}
1122 
1123 	*changed = false;
1124 	return RCODE_COMPLETE;
1125 }
1126 
1127 static void fw_device_refresh(struct work_struct *work)
1128 {
1129 	struct fw_device *device =
1130 		container_of(work, struct fw_device, work.work);
1131 	struct fw_card *card = device->card;
1132 	int ret, node_id = device->node_id;
1133 	bool changed;
1134 
1135 	ret = reread_config_rom(device, device->generation, &changed);
1136 	if (ret != RCODE_COMPLETE)
1137 		goto failed_config_rom;
1138 
1139 	if (!changed) {
1140 		if (atomic_cmpxchg(&device->state,
1141 				   FW_DEVICE_INITIALIZING,
1142 				   FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1143 			goto gone;
1144 
1145 		fw_device_update(work);
1146 		device->config_rom_retries = 0;
1147 		goto out;
1148 	}
1149 
1150 	/*
1151 	 * Something changed.  We keep things simple and don't investigate
1152 	 * further.  We just destroy all previous units and create new ones.
1153 	 */
1154 	device_for_each_child(&device->device, NULL, shutdown_unit);
1155 
1156 	ret = read_config_rom(device, device->generation);
1157 	if (ret != RCODE_COMPLETE)
1158 		goto failed_config_rom;
1159 
1160 	fw_device_cdev_update(device);
1161 	create_units(device);
1162 
1163 	/* Userspace may want to re-read attributes. */
1164 	kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1165 
1166 	if (atomic_cmpxchg(&device->state,
1167 			   FW_DEVICE_INITIALIZING,
1168 			   FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1169 		goto gone;
1170 
1171 	fw_notice(card, "refreshed device %s\n", dev_name(&device->device));
1172 	device->config_rom_retries = 0;
1173 	goto out;
1174 
1175  failed_config_rom:
1176 	if (device->config_rom_retries < MAX_RETRIES &&
1177 	    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1178 		device->config_rom_retries++;
1179 		fw_schedule_device_work(device, RETRY_DELAY);
1180 		return;
1181 	}
1182 
1183 	fw_notice(card, "giving up on refresh of device %s: %s\n",
1184 		  dev_name(&device->device), fw_rcode_string(ret));
1185  gone:
1186 	atomic_set(&device->state, FW_DEVICE_GONE);
1187 	device->workfn = fw_device_shutdown;
1188 	fw_schedule_device_work(device, SHUTDOWN_DELAY);
1189  out:
1190 	if (node_id == card->root_node->node_id)
1191 		fw_schedule_bm_work(card, 0);
1192 }
1193 
1194 static void fw_device_workfn(struct work_struct *work)
1195 {
1196 	struct fw_device *device = container_of(to_delayed_work(work),
1197 						struct fw_device, work);
1198 	device->workfn(work);
1199 }
1200 
1201 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1202 {
1203 	struct fw_device *device;
1204 
1205 	switch (event) {
1206 	case FW_NODE_CREATED:
1207 		/*
1208 		 * Attempt to scan the node, regardless whether its self ID has
1209 		 * the L (link active) flag set or not.  Some broken devices
1210 		 * send L=0 but have an up-and-running link; others send L=1
1211 		 * without actually having a link.
1212 		 */
1213  create:
1214 		device = kzalloc(sizeof(*device), GFP_ATOMIC);
1215 		if (device == NULL)
1216 			break;
1217 
1218 		/*
1219 		 * Do minimal initialization of the device here, the
1220 		 * rest will happen in fw_device_init().
1221 		 *
1222 		 * Attention:  A lot of things, even fw_device_get(),
1223 		 * cannot be done before fw_device_init() finished!
1224 		 * You can basically just check device->state and
1225 		 * schedule work until then, but only while holding
1226 		 * card->lock.
1227 		 */
1228 		atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1229 		device->card = fw_card_get(card);
1230 		device->node = fw_node_get(node);
1231 		device->node_id = node->node_id;
1232 		device->generation = card->generation;
1233 		device->is_local = node == card->local_node;
1234 		mutex_init(&device->client_list_mutex);
1235 		INIT_LIST_HEAD(&device->client_list);
1236 
1237 		/*
1238 		 * Set the node data to point back to this device so
1239 		 * FW_NODE_UPDATED callbacks can update the node_id
1240 		 * and generation for the device.
1241 		 */
1242 		node->data = device;
1243 
1244 		/*
1245 		 * Many devices are slow to respond after bus resets,
1246 		 * especially if they are bus powered and go through
1247 		 * power-up after getting plugged in.  We schedule the
1248 		 * first config rom scan half a second after bus reset.
1249 		 */
1250 		device->workfn = fw_device_init;
1251 		INIT_DELAYED_WORK(&device->work, fw_device_workfn);
1252 		fw_schedule_device_work(device, INITIAL_DELAY);
1253 		break;
1254 
1255 	case FW_NODE_INITIATED_RESET:
1256 	case FW_NODE_LINK_ON:
1257 		device = node->data;
1258 		if (device == NULL)
1259 			goto create;
1260 
1261 		device->node_id = node->node_id;
1262 		smp_wmb();  /* update node_id before generation */
1263 		device->generation = card->generation;
1264 		if (atomic_cmpxchg(&device->state,
1265 			    FW_DEVICE_RUNNING,
1266 			    FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1267 			device->workfn = fw_device_refresh;
1268 			fw_schedule_device_work(device,
1269 				device->is_local ? 0 : INITIAL_DELAY);
1270 		}
1271 		break;
1272 
1273 	case FW_NODE_UPDATED:
1274 		device = node->data;
1275 		if (device == NULL)
1276 			break;
1277 
1278 		device->node_id = node->node_id;
1279 		smp_wmb();  /* update node_id before generation */
1280 		device->generation = card->generation;
1281 		if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1282 			device->workfn = fw_device_update;
1283 			fw_schedule_device_work(device, 0);
1284 		}
1285 		break;
1286 
1287 	case FW_NODE_DESTROYED:
1288 	case FW_NODE_LINK_OFF:
1289 		if (!node->data)
1290 			break;
1291 
1292 		/*
1293 		 * Destroy the device associated with the node.  There
1294 		 * are two cases here: either the device is fully
1295 		 * initialized (FW_DEVICE_RUNNING) or we're in the
1296 		 * process of reading its config rom
1297 		 * (FW_DEVICE_INITIALIZING).  If it is fully
1298 		 * initialized we can reuse device->work to schedule a
1299 		 * full fw_device_shutdown().  If not, there's work
1300 		 * scheduled to read it's config rom, and we just put
1301 		 * the device in shutdown state to have that code fail
1302 		 * to create the device.
1303 		 */
1304 		device = node->data;
1305 		if (atomic_xchg(&device->state,
1306 				FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1307 			device->workfn = fw_device_shutdown;
1308 			fw_schedule_device_work(device,
1309 				list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1310 		}
1311 		break;
1312 	}
1313 }
1314