1 /*
2  * Device probing and sysfs code.
3  *
4  * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software Foundation,
18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19  */
20 
21 #include <linux/bug.h>
22 #include <linux/ctype.h>
23 #include <linux/delay.h>
24 #include <linux/device.h>
25 #include <linux/errno.h>
26 #include <linux/firewire.h>
27 #include <linux/firewire-constants.h>
28 #include <linux/idr.h>
29 #include <linux/jiffies.h>
30 #include <linux/kobject.h>
31 #include <linux/list.h>
32 #include <linux/mod_devicetable.h>
33 #include <linux/module.h>
34 #include <linux/mutex.h>
35 #include <linux/rwsem.h>
36 #include <linux/slab.h>
37 #include <linux/spinlock.h>
38 #include <linux/string.h>
39 #include <linux/workqueue.h>
40 
41 #include <asm/atomic.h>
42 #include <asm/byteorder.h>
43 #include <asm/system.h>
44 
45 #include "core.h"
46 
47 void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p)
48 {
49 	ci->p = p + 1;
50 	ci->end = ci->p + (p[0] >> 16);
51 }
52 EXPORT_SYMBOL(fw_csr_iterator_init);
53 
54 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
55 {
56 	*key = *ci->p >> 24;
57 	*value = *ci->p & 0xffffff;
58 
59 	return ci->p++ < ci->end;
60 }
61 EXPORT_SYMBOL(fw_csr_iterator_next);
62 
63 static const u32 *search_leaf(const u32 *directory, int search_key)
64 {
65 	struct fw_csr_iterator ci;
66 	int last_key = 0, key, value;
67 
68 	fw_csr_iterator_init(&ci, directory);
69 	while (fw_csr_iterator_next(&ci, &key, &value)) {
70 		if (last_key == search_key &&
71 		    key == (CSR_DESCRIPTOR | CSR_LEAF))
72 			return ci.p - 1 + value;
73 
74 		last_key = key;
75 	}
76 
77 	return NULL;
78 }
79 
80 static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
81 {
82 	unsigned int quadlets, i;
83 	char c;
84 
85 	if (!size || !buf)
86 		return -EINVAL;
87 
88 	quadlets = min(block[0] >> 16, 256U);
89 	if (quadlets < 2)
90 		return -ENODATA;
91 
92 	if (block[1] != 0 || block[2] != 0)
93 		/* unknown language/character set */
94 		return -ENODATA;
95 
96 	block += 3;
97 	quadlets -= 2;
98 	for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
99 		c = block[i / 4] >> (24 - 8 * (i % 4));
100 		if (c == '\0')
101 			break;
102 		buf[i] = c;
103 	}
104 	buf[i] = '\0';
105 
106 	return i;
107 }
108 
109 /**
110  * fw_csr_string() - reads a string from the configuration ROM
111  * @directory:	e.g. root directory or unit directory
112  * @key:	the key of the preceding directory entry
113  * @buf:	where to put the string
114  * @size:	size of @buf, in bytes
115  *
116  * The string is taken from a minimal ASCII text descriptor leaf after
117  * the immediate entry with @key.  The string is zero-terminated.
118  * Returns strlen(buf) or a negative error code.
119  */
120 int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
121 {
122 	const u32 *leaf = search_leaf(directory, key);
123 	if (!leaf)
124 		return -ENOENT;
125 
126 	return textual_leaf_to_string(leaf, buf, size);
127 }
128 EXPORT_SYMBOL(fw_csr_string);
129 
130 static void get_ids(const u32 *directory, int *id)
131 {
132 	struct fw_csr_iterator ci;
133 	int key, value;
134 
135 	fw_csr_iterator_init(&ci, directory);
136 	while (fw_csr_iterator_next(&ci, &key, &value)) {
137 		switch (key) {
138 		case CSR_VENDOR:	id[0] = value; break;
139 		case CSR_MODEL:		id[1] = value; break;
140 		case CSR_SPECIFIER_ID:	id[2] = value; break;
141 		case CSR_VERSION:	id[3] = value; break;
142 		}
143 	}
144 }
145 
146 static void get_modalias_ids(struct fw_unit *unit, int *id)
147 {
148 	get_ids(&fw_parent_device(unit)->config_rom[5], id);
149 	get_ids(unit->directory, id);
150 }
151 
152 static bool match_ids(const struct ieee1394_device_id *id_table, int *id)
153 {
154 	int match = 0;
155 
156 	if (id[0] == id_table->vendor_id)
157 		match |= IEEE1394_MATCH_VENDOR_ID;
158 	if (id[1] == id_table->model_id)
159 		match |= IEEE1394_MATCH_MODEL_ID;
160 	if (id[2] == id_table->specifier_id)
161 		match |= IEEE1394_MATCH_SPECIFIER_ID;
162 	if (id[3] == id_table->version)
163 		match |= IEEE1394_MATCH_VERSION;
164 
165 	return (match & id_table->match_flags) == id_table->match_flags;
166 }
167 
168 static bool is_fw_unit(struct device *dev);
169 
170 static int fw_unit_match(struct device *dev, struct device_driver *drv)
171 {
172 	const struct ieee1394_device_id *id_table =
173 			container_of(drv, struct fw_driver, driver)->id_table;
174 	int id[] = {0, 0, 0, 0};
175 
176 	/* We only allow binding to fw_units. */
177 	if (!is_fw_unit(dev))
178 		return 0;
179 
180 	get_modalias_ids(fw_unit(dev), id);
181 
182 	for (; id_table->match_flags != 0; id_table++)
183 		if (match_ids(id_table, id))
184 			return 1;
185 
186 	return 0;
187 }
188 
189 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
190 {
191 	int id[] = {0, 0, 0, 0};
192 
193 	get_modalias_ids(unit, id);
194 
195 	return snprintf(buffer, buffer_size,
196 			"ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
197 			id[0], id[1], id[2], id[3]);
198 }
199 
200 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
201 {
202 	struct fw_unit *unit = fw_unit(dev);
203 	char modalias[64];
204 
205 	get_modalias(unit, modalias, sizeof(modalias));
206 
207 	if (add_uevent_var(env, "MODALIAS=%s", modalias))
208 		return -ENOMEM;
209 
210 	return 0;
211 }
212 
213 struct bus_type fw_bus_type = {
214 	.name = "firewire",
215 	.match = fw_unit_match,
216 };
217 EXPORT_SYMBOL(fw_bus_type);
218 
219 int fw_device_enable_phys_dma(struct fw_device *device)
220 {
221 	int generation = device->generation;
222 
223 	/* device->node_id, accessed below, must not be older than generation */
224 	smp_rmb();
225 
226 	return device->card->driver->enable_phys_dma(device->card,
227 						     device->node_id,
228 						     generation);
229 }
230 EXPORT_SYMBOL(fw_device_enable_phys_dma);
231 
232 struct config_rom_attribute {
233 	struct device_attribute attr;
234 	u32 key;
235 };
236 
237 static ssize_t show_immediate(struct device *dev,
238 			      struct device_attribute *dattr, char *buf)
239 {
240 	struct config_rom_attribute *attr =
241 		container_of(dattr, struct config_rom_attribute, attr);
242 	struct fw_csr_iterator ci;
243 	const u32 *dir;
244 	int key, value, ret = -ENOENT;
245 
246 	down_read(&fw_device_rwsem);
247 
248 	if (is_fw_unit(dev))
249 		dir = fw_unit(dev)->directory;
250 	else
251 		dir = fw_device(dev)->config_rom + 5;
252 
253 	fw_csr_iterator_init(&ci, dir);
254 	while (fw_csr_iterator_next(&ci, &key, &value))
255 		if (attr->key == key) {
256 			ret = snprintf(buf, buf ? PAGE_SIZE : 0,
257 				       "0x%06x\n", value);
258 			break;
259 		}
260 
261 	up_read(&fw_device_rwsem);
262 
263 	return ret;
264 }
265 
266 #define IMMEDIATE_ATTR(name, key)				\
267 	{ __ATTR(name, S_IRUGO, show_immediate, NULL), key }
268 
269 static ssize_t show_text_leaf(struct device *dev,
270 			      struct device_attribute *dattr, char *buf)
271 {
272 	struct config_rom_attribute *attr =
273 		container_of(dattr, struct config_rom_attribute, attr);
274 	const u32 *dir;
275 	size_t bufsize;
276 	char dummy_buf[2];
277 	int ret;
278 
279 	down_read(&fw_device_rwsem);
280 
281 	if (is_fw_unit(dev))
282 		dir = fw_unit(dev)->directory;
283 	else
284 		dir = fw_device(dev)->config_rom + 5;
285 
286 	if (buf) {
287 		bufsize = PAGE_SIZE - 1;
288 	} else {
289 		buf = dummy_buf;
290 		bufsize = 1;
291 	}
292 
293 	ret = fw_csr_string(dir, attr->key, buf, bufsize);
294 
295 	if (ret >= 0) {
296 		/* Strip trailing whitespace and add newline. */
297 		while (ret > 0 && isspace(buf[ret - 1]))
298 			ret--;
299 		strcpy(buf + ret, "\n");
300 		ret++;
301 	}
302 
303 	up_read(&fw_device_rwsem);
304 
305 	return ret;
306 }
307 
308 #define TEXT_LEAF_ATTR(name, key)				\
309 	{ __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
310 
311 static struct config_rom_attribute config_rom_attributes[] = {
312 	IMMEDIATE_ATTR(vendor, CSR_VENDOR),
313 	IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
314 	IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
315 	IMMEDIATE_ATTR(version, CSR_VERSION),
316 	IMMEDIATE_ATTR(model, CSR_MODEL),
317 	TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
318 	TEXT_LEAF_ATTR(model_name, CSR_MODEL),
319 	TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
320 };
321 
322 static void init_fw_attribute_group(struct device *dev,
323 				    struct device_attribute *attrs,
324 				    struct fw_attribute_group *group)
325 {
326 	struct device_attribute *attr;
327 	int i, j;
328 
329 	for (j = 0; attrs[j].attr.name != NULL; j++)
330 		group->attrs[j] = &attrs[j].attr;
331 
332 	for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
333 		attr = &config_rom_attributes[i].attr;
334 		if (attr->show(dev, attr, NULL) < 0)
335 			continue;
336 		group->attrs[j++] = &attr->attr;
337 	}
338 
339 	group->attrs[j] = NULL;
340 	group->groups[0] = &group->group;
341 	group->groups[1] = NULL;
342 	group->group.attrs = group->attrs;
343 	dev->groups = (const struct attribute_group **) group->groups;
344 }
345 
346 static ssize_t modalias_show(struct device *dev,
347 			     struct device_attribute *attr, char *buf)
348 {
349 	struct fw_unit *unit = fw_unit(dev);
350 	int length;
351 
352 	length = get_modalias(unit, buf, PAGE_SIZE);
353 	strcpy(buf + length, "\n");
354 
355 	return length + 1;
356 }
357 
358 static ssize_t rom_index_show(struct device *dev,
359 			      struct device_attribute *attr, char *buf)
360 {
361 	struct fw_device *device = fw_device(dev->parent);
362 	struct fw_unit *unit = fw_unit(dev);
363 
364 	return snprintf(buf, PAGE_SIZE, "%d\n",
365 			(int)(unit->directory - device->config_rom));
366 }
367 
368 static struct device_attribute fw_unit_attributes[] = {
369 	__ATTR_RO(modalias),
370 	__ATTR_RO(rom_index),
371 	__ATTR_NULL,
372 };
373 
374 static ssize_t config_rom_show(struct device *dev,
375 			       struct device_attribute *attr, char *buf)
376 {
377 	struct fw_device *device = fw_device(dev);
378 	size_t length;
379 
380 	down_read(&fw_device_rwsem);
381 	length = device->config_rom_length * 4;
382 	memcpy(buf, device->config_rom, length);
383 	up_read(&fw_device_rwsem);
384 
385 	return length;
386 }
387 
388 static ssize_t guid_show(struct device *dev,
389 			 struct device_attribute *attr, char *buf)
390 {
391 	struct fw_device *device = fw_device(dev);
392 	int ret;
393 
394 	down_read(&fw_device_rwsem);
395 	ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
396 		       device->config_rom[3], device->config_rom[4]);
397 	up_read(&fw_device_rwsem);
398 
399 	return ret;
400 }
401 
402 static int units_sprintf(char *buf, const u32 *directory)
403 {
404 	struct fw_csr_iterator ci;
405 	int key, value;
406 	int specifier_id = 0;
407 	int version = 0;
408 
409 	fw_csr_iterator_init(&ci, directory);
410 	while (fw_csr_iterator_next(&ci, &key, &value)) {
411 		switch (key) {
412 		case CSR_SPECIFIER_ID:
413 			specifier_id = value;
414 			break;
415 		case CSR_VERSION:
416 			version = value;
417 			break;
418 		}
419 	}
420 
421 	return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
422 }
423 
424 static ssize_t units_show(struct device *dev,
425 			  struct device_attribute *attr, char *buf)
426 {
427 	struct fw_device *device = fw_device(dev);
428 	struct fw_csr_iterator ci;
429 	int key, value, i = 0;
430 
431 	down_read(&fw_device_rwsem);
432 	fw_csr_iterator_init(&ci, &device->config_rom[5]);
433 	while (fw_csr_iterator_next(&ci, &key, &value)) {
434 		if (key != (CSR_UNIT | CSR_DIRECTORY))
435 			continue;
436 		i += units_sprintf(&buf[i], ci.p + value - 1);
437 		if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
438 			break;
439 	}
440 	up_read(&fw_device_rwsem);
441 
442 	if (i)
443 		buf[i - 1] = '\n';
444 
445 	return i;
446 }
447 
448 static struct device_attribute fw_device_attributes[] = {
449 	__ATTR_RO(config_rom),
450 	__ATTR_RO(guid),
451 	__ATTR_RO(units),
452 	__ATTR_NULL,
453 };
454 
455 static int read_rom(struct fw_device *device,
456 		    int generation, int index, u32 *data)
457 {
458 	int rcode;
459 
460 	/* device->node_id, accessed below, must not be older than generation */
461 	smp_rmb();
462 
463 	rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
464 			device->node_id, generation, device->max_speed,
465 			(CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
466 			data, 4);
467 	be32_to_cpus(data);
468 
469 	return rcode;
470 }
471 
472 #define MAX_CONFIG_ROM_SIZE 256
473 
474 /*
475  * Read the bus info block, perform a speed probe, and read all of the rest of
476  * the config ROM.  We do all this with a cached bus generation.  If the bus
477  * generation changes under us, read_config_rom will fail and get retried.
478  * It's better to start all over in this case because the node from which we
479  * are reading the ROM may have changed the ROM during the reset.
480  */
481 static int read_config_rom(struct fw_device *device, int generation)
482 {
483 	const u32 *old_rom, *new_rom;
484 	u32 *rom, *stack;
485 	u32 sp, key;
486 	int i, end, length, ret = -1;
487 
488 	rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
489 		      sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
490 	if (rom == NULL)
491 		return -ENOMEM;
492 
493 	stack = &rom[MAX_CONFIG_ROM_SIZE];
494 	memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
495 
496 	device->max_speed = SCODE_100;
497 
498 	/* First read the bus info block. */
499 	for (i = 0; i < 5; i++) {
500 		if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
501 			goto out;
502 		/*
503 		 * As per IEEE1212 7.2, during power-up, devices can
504 		 * reply with a 0 for the first quadlet of the config
505 		 * rom to indicate that they are booting (for example,
506 		 * if the firmware is on the disk of a external
507 		 * harddisk).  In that case we just fail, and the
508 		 * retry mechanism will try again later.
509 		 */
510 		if (i == 0 && rom[i] == 0)
511 			goto out;
512 	}
513 
514 	device->max_speed = device->node->max_speed;
515 
516 	/*
517 	 * Determine the speed of
518 	 *   - devices with link speed less than PHY speed,
519 	 *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
520 	 *   - all devices if there are 1394b repeaters.
521 	 * Note, we cannot use the bus info block's link_spd as starting point
522 	 * because some buggy firmwares set it lower than necessary and because
523 	 * 1394-1995 nodes do not have the field.
524 	 */
525 	if ((rom[2] & 0x7) < device->max_speed ||
526 	    device->max_speed == SCODE_BETA ||
527 	    device->card->beta_repeaters_present) {
528 		u32 dummy;
529 
530 		/* for S1600 and S3200 */
531 		if (device->max_speed == SCODE_BETA)
532 			device->max_speed = device->card->link_speed;
533 
534 		while (device->max_speed > SCODE_100) {
535 			if (read_rom(device, generation, 0, &dummy) ==
536 			    RCODE_COMPLETE)
537 				break;
538 			device->max_speed--;
539 		}
540 	}
541 
542 	/*
543 	 * Now parse the config rom.  The config rom is a recursive
544 	 * directory structure so we parse it using a stack of
545 	 * references to the blocks that make up the structure.  We
546 	 * push a reference to the root directory on the stack to
547 	 * start things off.
548 	 */
549 	length = i;
550 	sp = 0;
551 	stack[sp++] = 0xc0000005;
552 	while (sp > 0) {
553 		/*
554 		 * Pop the next block reference of the stack.  The
555 		 * lower 24 bits is the offset into the config rom,
556 		 * the upper 8 bits are the type of the reference the
557 		 * block.
558 		 */
559 		key = stack[--sp];
560 		i = key & 0xffffff;
561 		if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE))
562 			goto out;
563 
564 		/* Read header quadlet for the block to get the length. */
565 		if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
566 			goto out;
567 		end = i + (rom[i] >> 16) + 1;
568 		if (end > MAX_CONFIG_ROM_SIZE) {
569 			/*
570 			 * This block extends outside the config ROM which is
571 			 * a firmware bug.  Ignore this whole block, i.e.
572 			 * simply set a fake block length of 0.
573 			 */
574 			fw_error("skipped invalid ROM block %x at %llx\n",
575 				 rom[i],
576 				 i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
577 			rom[i] = 0;
578 			end = i;
579 		}
580 		i++;
581 
582 		/*
583 		 * Now read in the block.  If this is a directory
584 		 * block, check the entries as we read them to see if
585 		 * it references another block, and push it in that case.
586 		 */
587 		for (; i < end; i++) {
588 			if (read_rom(device, generation, i, &rom[i]) !=
589 			    RCODE_COMPLETE)
590 				goto out;
591 
592 			if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
593 				continue;
594 			/*
595 			 * Offset points outside the ROM.  May be a firmware
596 			 * bug or an Extended ROM entry (IEEE 1212-2001 clause
597 			 * 7.7.18).  Simply overwrite this pointer here by a
598 			 * fake immediate entry so that later iterators over
599 			 * the ROM don't have to check offsets all the time.
600 			 */
601 			if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
602 				fw_error("skipped unsupported ROM entry %x at %llx\n",
603 					 rom[i],
604 					 i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
605 				rom[i] = 0;
606 				continue;
607 			}
608 			stack[sp++] = i + rom[i];
609 		}
610 		if (length < i)
611 			length = i;
612 	}
613 
614 	old_rom = device->config_rom;
615 	new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
616 	if (new_rom == NULL)
617 		goto out;
618 
619 	down_write(&fw_device_rwsem);
620 	device->config_rom = new_rom;
621 	device->config_rom_length = length;
622 	up_write(&fw_device_rwsem);
623 
624 	kfree(old_rom);
625 	ret = 0;
626 	device->max_rec	= rom[2] >> 12 & 0xf;
627 	device->cmc	= rom[2] >> 30 & 1;
628 	device->irmc	= rom[2] >> 31 & 1;
629  out:
630 	kfree(rom);
631 
632 	return ret;
633 }
634 
635 static void fw_unit_release(struct device *dev)
636 {
637 	struct fw_unit *unit = fw_unit(dev);
638 
639 	kfree(unit);
640 }
641 
642 static struct device_type fw_unit_type = {
643 	.uevent		= fw_unit_uevent,
644 	.release	= fw_unit_release,
645 };
646 
647 static bool is_fw_unit(struct device *dev)
648 {
649 	return dev->type == &fw_unit_type;
650 }
651 
652 static void create_units(struct fw_device *device)
653 {
654 	struct fw_csr_iterator ci;
655 	struct fw_unit *unit;
656 	int key, value, i;
657 
658 	i = 0;
659 	fw_csr_iterator_init(&ci, &device->config_rom[5]);
660 	while (fw_csr_iterator_next(&ci, &key, &value)) {
661 		if (key != (CSR_UNIT | CSR_DIRECTORY))
662 			continue;
663 
664 		/*
665 		 * Get the address of the unit directory and try to
666 		 * match the drivers id_tables against it.
667 		 */
668 		unit = kzalloc(sizeof(*unit), GFP_KERNEL);
669 		if (unit == NULL) {
670 			fw_error("failed to allocate memory for unit\n");
671 			continue;
672 		}
673 
674 		unit->directory = ci.p + value - 1;
675 		unit->device.bus = &fw_bus_type;
676 		unit->device.type = &fw_unit_type;
677 		unit->device.parent = &device->device;
678 		dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
679 
680 		BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
681 				ARRAY_SIZE(fw_unit_attributes) +
682 				ARRAY_SIZE(config_rom_attributes));
683 		init_fw_attribute_group(&unit->device,
684 					fw_unit_attributes,
685 					&unit->attribute_group);
686 
687 		if (device_register(&unit->device) < 0)
688 			goto skip_unit;
689 
690 		continue;
691 
692 	skip_unit:
693 		kfree(unit);
694 	}
695 }
696 
697 static int shutdown_unit(struct device *device, void *data)
698 {
699 	device_unregister(device);
700 
701 	return 0;
702 }
703 
704 /*
705  * fw_device_rwsem acts as dual purpose mutex:
706  *   - serializes accesses to fw_device_idr,
707  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
708  *     fw_unit.directory, unless those accesses happen at safe occasions
709  */
710 DECLARE_RWSEM(fw_device_rwsem);
711 
712 DEFINE_IDR(fw_device_idr);
713 int fw_cdev_major;
714 
715 struct fw_device *fw_device_get_by_devt(dev_t devt)
716 {
717 	struct fw_device *device;
718 
719 	down_read(&fw_device_rwsem);
720 	device = idr_find(&fw_device_idr, MINOR(devt));
721 	if (device)
722 		fw_device_get(device);
723 	up_read(&fw_device_rwsem);
724 
725 	return device;
726 }
727 
728 /*
729  * These defines control the retry behavior for reading the config
730  * rom.  It shouldn't be necessary to tweak these; if the device
731  * doesn't respond to a config rom read within 10 seconds, it's not
732  * going to respond at all.  As for the initial delay, a lot of
733  * devices will be able to respond within half a second after bus
734  * reset.  On the other hand, it's not really worth being more
735  * aggressive than that, since it scales pretty well; if 10 devices
736  * are plugged in, they're all getting read within one second.
737  */
738 
739 #define MAX_RETRIES	10
740 #define RETRY_DELAY	(3 * HZ)
741 #define INITIAL_DELAY	(HZ / 2)
742 #define SHUTDOWN_DELAY	(2 * HZ)
743 
744 static void fw_device_shutdown(struct work_struct *work)
745 {
746 	struct fw_device *device =
747 		container_of(work, struct fw_device, work.work);
748 	int minor = MINOR(device->device.devt);
749 
750 	if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
751 	    && !list_empty(&device->card->link)) {
752 		schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
753 		return;
754 	}
755 
756 	if (atomic_cmpxchg(&device->state,
757 			   FW_DEVICE_GONE,
758 			   FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
759 		return;
760 
761 	fw_device_cdev_remove(device);
762 	device_for_each_child(&device->device, NULL, shutdown_unit);
763 	device_unregister(&device->device);
764 
765 	down_write(&fw_device_rwsem);
766 	idr_remove(&fw_device_idr, minor);
767 	up_write(&fw_device_rwsem);
768 
769 	fw_device_put(device);
770 }
771 
772 static void fw_device_release(struct device *dev)
773 {
774 	struct fw_device *device = fw_device(dev);
775 	struct fw_card *card = device->card;
776 	unsigned long flags;
777 
778 	/*
779 	 * Take the card lock so we don't set this to NULL while a
780 	 * FW_NODE_UPDATED callback is being handled or while the
781 	 * bus manager work looks at this node.
782 	 */
783 	spin_lock_irqsave(&card->lock, flags);
784 	device->node->data = NULL;
785 	spin_unlock_irqrestore(&card->lock, flags);
786 
787 	fw_node_put(device->node);
788 	kfree(device->config_rom);
789 	kfree(device);
790 	fw_card_put(card);
791 }
792 
793 static struct device_type fw_device_type = {
794 	.release = fw_device_release,
795 };
796 
797 static bool is_fw_device(struct device *dev)
798 {
799 	return dev->type == &fw_device_type;
800 }
801 
802 static int update_unit(struct device *dev, void *data)
803 {
804 	struct fw_unit *unit = fw_unit(dev);
805 	struct fw_driver *driver = (struct fw_driver *)dev->driver;
806 
807 	if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
808 		device_lock(dev);
809 		driver->update(unit);
810 		device_unlock(dev);
811 	}
812 
813 	return 0;
814 }
815 
816 static void fw_device_update(struct work_struct *work)
817 {
818 	struct fw_device *device =
819 		container_of(work, struct fw_device, work.work);
820 
821 	fw_device_cdev_update(device);
822 	device_for_each_child(&device->device, NULL, update_unit);
823 }
824 
825 /*
826  * If a device was pending for deletion because its node went away but its
827  * bus info block and root directory header matches that of a newly discovered
828  * device, revive the existing fw_device.
829  * The newly allocated fw_device becomes obsolete instead.
830  */
831 static int lookup_existing_device(struct device *dev, void *data)
832 {
833 	struct fw_device *old = fw_device(dev);
834 	struct fw_device *new = data;
835 	struct fw_card *card = new->card;
836 	int match = 0;
837 
838 	if (!is_fw_device(dev))
839 		return 0;
840 
841 	down_read(&fw_device_rwsem); /* serialize config_rom access */
842 	spin_lock_irq(&card->lock);  /* serialize node access */
843 
844 	if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
845 	    atomic_cmpxchg(&old->state,
846 			   FW_DEVICE_GONE,
847 			   FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
848 		struct fw_node *current_node = new->node;
849 		struct fw_node *obsolete_node = old->node;
850 
851 		new->node = obsolete_node;
852 		new->node->data = new;
853 		old->node = current_node;
854 		old->node->data = old;
855 
856 		old->max_speed = new->max_speed;
857 		old->node_id = current_node->node_id;
858 		smp_wmb();  /* update node_id before generation */
859 		old->generation = card->generation;
860 		old->config_rom_retries = 0;
861 		fw_notify("rediscovered device %s\n", dev_name(dev));
862 
863 		PREPARE_DELAYED_WORK(&old->work, fw_device_update);
864 		schedule_delayed_work(&old->work, 0);
865 
866 		if (current_node == card->root_node)
867 			fw_schedule_bm_work(card, 0);
868 
869 		match = 1;
870 	}
871 
872 	spin_unlock_irq(&card->lock);
873 	up_read(&fw_device_rwsem);
874 
875 	return match;
876 }
877 
878 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
879 
880 static void set_broadcast_channel(struct fw_device *device, int generation)
881 {
882 	struct fw_card *card = device->card;
883 	__be32 data;
884 	int rcode;
885 
886 	if (!card->broadcast_channel_allocated)
887 		return;
888 
889 	/*
890 	 * The Broadcast_Channel Valid bit is required by nodes which want to
891 	 * transmit on this channel.  Such transmissions are practically
892 	 * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
893 	 * to be IRM capable and have a max_rec of 8 or more.  We use this fact
894 	 * to narrow down to which nodes we send Broadcast_Channel updates.
895 	 */
896 	if (!device->irmc || device->max_rec < 8)
897 		return;
898 
899 	/*
900 	 * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
901 	 * Perform a read test first.
902 	 */
903 	if (device->bc_implemented == BC_UNKNOWN) {
904 		rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
905 				device->node_id, generation, device->max_speed,
906 				CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
907 				&data, 4);
908 		switch (rcode) {
909 		case RCODE_COMPLETE:
910 			if (data & cpu_to_be32(1 << 31)) {
911 				device->bc_implemented = BC_IMPLEMENTED;
912 				break;
913 			}
914 			/* else fall through to case address error */
915 		case RCODE_ADDRESS_ERROR:
916 			device->bc_implemented = BC_UNIMPLEMENTED;
917 		}
918 	}
919 
920 	if (device->bc_implemented == BC_IMPLEMENTED) {
921 		data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
922 				   BROADCAST_CHANNEL_VALID);
923 		fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
924 				device->node_id, generation, device->max_speed,
925 				CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
926 				&data, 4);
927 	}
928 }
929 
930 int fw_device_set_broadcast_channel(struct device *dev, void *gen)
931 {
932 	if (is_fw_device(dev))
933 		set_broadcast_channel(fw_device(dev), (long)gen);
934 
935 	return 0;
936 }
937 
938 static void fw_device_init(struct work_struct *work)
939 {
940 	struct fw_device *device =
941 		container_of(work, struct fw_device, work.work);
942 	struct device *revived_dev;
943 	int minor, ret;
944 
945 	/*
946 	 * All failure paths here set node->data to NULL, so that we
947 	 * don't try to do device_for_each_child() on a kfree()'d
948 	 * device.
949 	 */
950 
951 	if (read_config_rom(device, device->generation) < 0) {
952 		if (device->config_rom_retries < MAX_RETRIES &&
953 		    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
954 			device->config_rom_retries++;
955 			schedule_delayed_work(&device->work, RETRY_DELAY);
956 		} else {
957 			fw_notify("giving up on config rom for node id %x\n",
958 				  device->node_id);
959 			if (device->node == device->card->root_node)
960 				fw_schedule_bm_work(device->card, 0);
961 			fw_device_release(&device->device);
962 		}
963 		return;
964 	}
965 
966 	revived_dev = device_find_child(device->card->device,
967 					device, lookup_existing_device);
968 	if (revived_dev) {
969 		put_device(revived_dev);
970 		fw_device_release(&device->device);
971 
972 		return;
973 	}
974 
975 	device_initialize(&device->device);
976 
977 	fw_device_get(device);
978 	down_write(&fw_device_rwsem);
979 	ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
980 	      idr_get_new(&fw_device_idr, device, &minor) :
981 	      -ENOMEM;
982 	up_write(&fw_device_rwsem);
983 
984 	if (ret < 0)
985 		goto error;
986 
987 	device->device.bus = &fw_bus_type;
988 	device->device.type = &fw_device_type;
989 	device->device.parent = device->card->device;
990 	device->device.devt = MKDEV(fw_cdev_major, minor);
991 	dev_set_name(&device->device, "fw%d", minor);
992 
993 	BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
994 			ARRAY_SIZE(fw_device_attributes) +
995 			ARRAY_SIZE(config_rom_attributes));
996 	init_fw_attribute_group(&device->device,
997 				fw_device_attributes,
998 				&device->attribute_group);
999 
1000 	if (device_add(&device->device)) {
1001 		fw_error("Failed to add device.\n");
1002 		goto error_with_cdev;
1003 	}
1004 
1005 	create_units(device);
1006 
1007 	/*
1008 	 * Transition the device to running state.  If it got pulled
1009 	 * out from under us while we did the intialization work, we
1010 	 * have to shut down the device again here.  Normally, though,
1011 	 * fw_node_event will be responsible for shutting it down when
1012 	 * necessary.  We have to use the atomic cmpxchg here to avoid
1013 	 * racing with the FW_NODE_DESTROYED case in
1014 	 * fw_node_event().
1015 	 */
1016 	if (atomic_cmpxchg(&device->state,
1017 			   FW_DEVICE_INITIALIZING,
1018 			   FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1019 		PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1020 		schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1021 	} else {
1022 		if (device->config_rom_retries)
1023 			fw_notify("created device %s: GUID %08x%08x, S%d00, "
1024 				  "%d config ROM retries\n",
1025 				  dev_name(&device->device),
1026 				  device->config_rom[3], device->config_rom[4],
1027 				  1 << device->max_speed,
1028 				  device->config_rom_retries);
1029 		else
1030 			fw_notify("created device %s: GUID %08x%08x, S%d00\n",
1031 				  dev_name(&device->device),
1032 				  device->config_rom[3], device->config_rom[4],
1033 				  1 << device->max_speed);
1034 		device->config_rom_retries = 0;
1035 
1036 		set_broadcast_channel(device, device->generation);
1037 	}
1038 
1039 	/*
1040 	 * Reschedule the IRM work if we just finished reading the
1041 	 * root node config rom.  If this races with a bus reset we
1042 	 * just end up running the IRM work a couple of extra times -
1043 	 * pretty harmless.
1044 	 */
1045 	if (device->node == device->card->root_node)
1046 		fw_schedule_bm_work(device->card, 0);
1047 
1048 	return;
1049 
1050  error_with_cdev:
1051 	down_write(&fw_device_rwsem);
1052 	idr_remove(&fw_device_idr, minor);
1053 	up_write(&fw_device_rwsem);
1054  error:
1055 	fw_device_put(device);		/* fw_device_idr's reference */
1056 
1057 	put_device(&device->device);	/* our reference */
1058 }
1059 
1060 enum {
1061 	REREAD_BIB_ERROR,
1062 	REREAD_BIB_GONE,
1063 	REREAD_BIB_UNCHANGED,
1064 	REREAD_BIB_CHANGED,
1065 };
1066 
1067 /* Reread and compare bus info block and header of root directory */
1068 static int reread_config_rom(struct fw_device *device, int generation)
1069 {
1070 	u32 q;
1071 	int i;
1072 
1073 	for (i = 0; i < 6; i++) {
1074 		if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
1075 			return REREAD_BIB_ERROR;
1076 
1077 		if (i == 0 && q == 0)
1078 			return REREAD_BIB_GONE;
1079 
1080 		if (q != device->config_rom[i])
1081 			return REREAD_BIB_CHANGED;
1082 	}
1083 
1084 	return REREAD_BIB_UNCHANGED;
1085 }
1086 
1087 static void fw_device_refresh(struct work_struct *work)
1088 {
1089 	struct fw_device *device =
1090 		container_of(work, struct fw_device, work.work);
1091 	struct fw_card *card = device->card;
1092 	int node_id = device->node_id;
1093 
1094 	switch (reread_config_rom(device, device->generation)) {
1095 	case REREAD_BIB_ERROR:
1096 		if (device->config_rom_retries < MAX_RETRIES / 2 &&
1097 		    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1098 			device->config_rom_retries++;
1099 			schedule_delayed_work(&device->work, RETRY_DELAY / 2);
1100 
1101 			return;
1102 		}
1103 		goto give_up;
1104 
1105 	case REREAD_BIB_GONE:
1106 		goto gone;
1107 
1108 	case REREAD_BIB_UNCHANGED:
1109 		if (atomic_cmpxchg(&device->state,
1110 				   FW_DEVICE_INITIALIZING,
1111 				   FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1112 			goto gone;
1113 
1114 		fw_device_update(work);
1115 		device->config_rom_retries = 0;
1116 		goto out;
1117 
1118 	case REREAD_BIB_CHANGED:
1119 		break;
1120 	}
1121 
1122 	/*
1123 	 * Something changed.  We keep things simple and don't investigate
1124 	 * further.  We just destroy all previous units and create new ones.
1125 	 */
1126 	device_for_each_child(&device->device, NULL, shutdown_unit);
1127 
1128 	if (read_config_rom(device, device->generation) < 0) {
1129 		if (device->config_rom_retries < MAX_RETRIES &&
1130 		    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1131 			device->config_rom_retries++;
1132 			schedule_delayed_work(&device->work, RETRY_DELAY);
1133 
1134 			return;
1135 		}
1136 		goto give_up;
1137 	}
1138 
1139 	fw_device_cdev_update(device);
1140 	create_units(device);
1141 
1142 	/* Userspace may want to re-read attributes. */
1143 	kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1144 
1145 	if (atomic_cmpxchg(&device->state,
1146 			   FW_DEVICE_INITIALIZING,
1147 			   FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1148 		goto gone;
1149 
1150 	fw_notify("refreshed device %s\n", dev_name(&device->device));
1151 	device->config_rom_retries = 0;
1152 	goto out;
1153 
1154  give_up:
1155 	fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
1156  gone:
1157 	atomic_set(&device->state, FW_DEVICE_GONE);
1158 	PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1159 	schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1160  out:
1161 	if (node_id == card->root_node->node_id)
1162 		fw_schedule_bm_work(card, 0);
1163 }
1164 
1165 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1166 {
1167 	struct fw_device *device;
1168 
1169 	switch (event) {
1170 	case FW_NODE_CREATED:
1171 	case FW_NODE_LINK_ON:
1172 		if (!node->link_on)
1173 			break;
1174  create:
1175 		device = kzalloc(sizeof(*device), GFP_ATOMIC);
1176 		if (device == NULL)
1177 			break;
1178 
1179 		/*
1180 		 * Do minimal intialization of the device here, the
1181 		 * rest will happen in fw_device_init().
1182 		 *
1183 		 * Attention:  A lot of things, even fw_device_get(),
1184 		 * cannot be done before fw_device_init() finished!
1185 		 * You can basically just check device->state and
1186 		 * schedule work until then, but only while holding
1187 		 * card->lock.
1188 		 */
1189 		atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1190 		device->card = fw_card_get(card);
1191 		device->node = fw_node_get(node);
1192 		device->node_id = node->node_id;
1193 		device->generation = card->generation;
1194 		device->is_local = node == card->local_node;
1195 		mutex_init(&device->client_list_mutex);
1196 		INIT_LIST_HEAD(&device->client_list);
1197 
1198 		/*
1199 		 * Set the node data to point back to this device so
1200 		 * FW_NODE_UPDATED callbacks can update the node_id
1201 		 * and generation for the device.
1202 		 */
1203 		node->data = device;
1204 
1205 		/*
1206 		 * Many devices are slow to respond after bus resets,
1207 		 * especially if they are bus powered and go through
1208 		 * power-up after getting plugged in.  We schedule the
1209 		 * first config rom scan half a second after bus reset.
1210 		 */
1211 		INIT_DELAYED_WORK(&device->work, fw_device_init);
1212 		schedule_delayed_work(&device->work, INITIAL_DELAY);
1213 		break;
1214 
1215 	case FW_NODE_INITIATED_RESET:
1216 		device = node->data;
1217 		if (device == NULL)
1218 			goto create;
1219 
1220 		device->node_id = node->node_id;
1221 		smp_wmb();  /* update node_id before generation */
1222 		device->generation = card->generation;
1223 		if (atomic_cmpxchg(&device->state,
1224 			    FW_DEVICE_RUNNING,
1225 			    FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1226 			PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1227 			schedule_delayed_work(&device->work,
1228 				device->is_local ? 0 : INITIAL_DELAY);
1229 		}
1230 		break;
1231 
1232 	case FW_NODE_UPDATED:
1233 		if (!node->link_on || node->data == NULL)
1234 			break;
1235 
1236 		device = node->data;
1237 		device->node_id = node->node_id;
1238 		smp_wmb();  /* update node_id before generation */
1239 		device->generation = card->generation;
1240 		if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1241 			PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1242 			schedule_delayed_work(&device->work, 0);
1243 		}
1244 		break;
1245 
1246 	case FW_NODE_DESTROYED:
1247 	case FW_NODE_LINK_OFF:
1248 		if (!node->data)
1249 			break;
1250 
1251 		/*
1252 		 * Destroy the device associated with the node.  There
1253 		 * are two cases here: either the device is fully
1254 		 * initialized (FW_DEVICE_RUNNING) or we're in the
1255 		 * process of reading its config rom
1256 		 * (FW_DEVICE_INITIALIZING).  If it is fully
1257 		 * initialized we can reuse device->work to schedule a
1258 		 * full fw_device_shutdown().  If not, there's work
1259 		 * scheduled to read it's config rom, and we just put
1260 		 * the device in shutdown state to have that code fail
1261 		 * to create the device.
1262 		 */
1263 		device = node->data;
1264 		if (atomic_xchg(&device->state,
1265 				FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1266 			PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1267 			schedule_delayed_work(&device->work,
1268 				list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1269 		}
1270 		break;
1271 	}
1272 }
1273