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
34void 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}
39EXPORT_SYMBOL(fw_csr_iterator_init);
40
41int 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}
48EXPORT_SYMBOL(fw_csr_iterator_next);
49
50static 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
67static 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 */
110int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
111{
112 const u32 *leaf = search_leaf(directory, search_key: key);
113 if (!leaf)
114 return -ENOENT;
115
116 return textual_leaf_to_string(block: leaf, buf, size);
117}
118EXPORT_SYMBOL(fw_csr_string);
119
120static 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
136static void get_modalias_ids(const struct fw_unit *unit, int *id)
137{
138 get_ids(directory: &fw_parent_device(unit)->config_rom[5], id);
139 get_ids(directory: unit->directory, id);
140}
141
142static 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
158static 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
174static bool is_fw_unit(struct device *dev);
175
176static 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
182static 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, drv: dev->driver));
188}
189
190static 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
198static 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(buf: buffer, size: buffer_size,
205 fmt: "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
206 id[0], id[1], id[2], id[3]);
207}
208
209static 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, buffer: modalias, buffer_size: sizeof(modalias));
215
216 if (add_uevent_var(env, format: "MODALIAS=%s", modalias))
217 return -ENOMEM;
218
219 return 0;
220}
221
222struct bus_type fw_bus_type = {
223 .name = "firewire",
224 .match = fw_unit_match,
225 .probe = fw_unit_probe,
226 .remove = fw_unit_remove,
227};
228EXPORT_SYMBOL(fw_bus_type);
229
230int 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}
241EXPORT_SYMBOL(fw_device_enable_phys_dma);
242
243struct config_rom_attribute {
244 struct device_attribute attr;
245 u32 key;
246};
247
248static 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(sem: &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, size: buf ? PAGE_SIZE : 0,
268 fmt: "0x%06x\n", value);
269 break;
270 }
271
272 up_read(sem: &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
280static 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(sem: &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(p: buf + ret, q: "\n");
311 ret++;
312 }
313
314 up_read(sem: &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
322static 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
333static 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
357static 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, buffer: buf, PAGE_SIZE);
364 strcpy(p: buf + length, q: "\n");
365
366 return length + 1;
367}
368
369static 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, fmt: "%td\n", unit->directory - device->config_rom);
376}
377
378static struct device_attribute fw_unit_attributes[] = {
379 __ATTR_RO(modalias),
380 __ATTR_RO(rom_index),
381 __ATTR_NULL,
382};
383
384static 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(sem: &fw_device_rwsem);
391 length = device->config_rom_length * 4;
392 memcpy(buf, device->config_rom, length);
393 up_read(sem: &fw_device_rwsem);
394
395 return length;
396}
397
398static 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(sem: &fw_device_rwsem);
405 ret = sysfs_emit(buf, fmt: "0x%08x%08x\n", device->config_rom[3], device->config_rom[4]);
406 up_read(sem: &fw_device_rwsem);
407
408 return ret;
409}
410
411static 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, fmt: "%u\n", device->is_local);
417}
418
419static 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, fmt: "0x%06x:0x%06x ", specifier_id, version);
439}
440
441static 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(sem: &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: &buf[i], directory: ci.p + value - 1);
454 if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
455 break;
456 }
457 up_read(sem: &fw_device_rwsem);
458
459 if (i)
460 buf[i - 1] = '\n';
461
462 return i;
463}
464
465static 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
473static 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(card: device->card,
484 TCODE_READ_QUADLET_REQUEST, destination_id: device->node_id,
485 generation, speed: device->max_speed, offset, payload: data, length: 4);
486 if (rcode != RCODE_BUSY)
487 break;
488 msleep(msecs: 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 */
505static 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(size: 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, index: i, data: &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, index: 0, data: &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, index: i, data: &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, fmt: "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, index: i, data: &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 fmt: "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(p: rom, size: length * 4, GFP_KERNEL);
648 if (new_rom == NULL) {
649 ret = -ENOMEM;
650 goto out;
651 }
652
653 down_write(sem: &fw_device_rwsem);
654 device->config_rom = new_rom;
655 device->config_rom_length = length;
656 up_write(sem: &fw_device_rwsem);
657
658 kfree(objp: 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(objp: rom);
665
666 return ret;
667}
668
669static 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(objp: unit);
675}
676
677static struct device_type fw_unit_type = {
678 .uevent = fw_unit_uevent,
679 .release = fw_unit_release,
680};
681
682static bool is_fw_unit(struct device *dev)
683{
684 return dev->type == &fw_unit_type;
685}
686
687static 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(size: 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(dev: &unit->device, name: "%s.%d", dev_name(dev: &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(dev: &unit->device,
717 attrs: fw_unit_attributes,
718 group: &unit->attribute_group);
719
720 if (device_register(dev: &unit->device) < 0)
721 goto skip_unit;
722
723 fw_device_get(device);
724 continue;
725
726 skip_unit:
727 kfree(objp: unit);
728 }
729}
730
731static int shutdown_unit(struct device *device, void *data)
732{
733 device_unregister(dev: 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 */
744DECLARE_RWSEM(fw_device_rwsem);
745
746DEFINE_IDR(fw_device_idr);
747int fw_cdev_major;
748
749struct fw_device *fw_device_get_by_devt(dev_t devt)
750{
751 struct fw_device *device;
752
753 down_read(sem: &fw_device_rwsem);
754 device = idr_find(&fw_device_idr, MINOR(devt));
755 if (device)
756 fw_device_get(device);
757 up_read(sem: &fw_device_rwsem);
758
759 return device;
760}
761
762struct workqueue_struct *fw_workqueue;
763EXPORT_SYMBOL(fw_workqueue);
764
765static void fw_schedule_device_work(struct fw_device *device,
766 unsigned long delay)
767{
768 queue_delayed_work(wq: fw_workqueue, dwork: &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
787static 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(head: &device->card->link)) {
796 fw_schedule_device_work(device, SHUTDOWN_DELAY);
797 return;
798 }
799
800 if (atomic_cmpxchg(v: &device->state,
801 old: FW_DEVICE_GONE,
802 new: FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
803 return;
804
805 fw_device_cdev_remove(device);
806 device_for_each_child(dev: &device->device, NULL, fn: shutdown_unit);
807 device_unregister(dev: &device->device);
808
809 down_write(sem: &fw_device_rwsem);
810 idr_remove(&fw_device_idr, id: minor);
811 up_write(sem: &fw_device_rwsem);
812
813 fw_device_put(device);
814}
815
816static 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(lock: &card->lock, flags);
830
831 fw_node_put(node: device->node);
832 kfree(objp: device->config_rom);
833 kfree(objp: device);
834 fw_card_put(card);
835}
836
837static struct device_type fw_device_type = {
838 .release = fw_device_release,
839};
840
841static bool is_fw_device(struct device *dev)
842{
843 return dev->type == &fw_device_type;
844}
845
846static 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
860static 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(dev: &device->device, NULL, fn: 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 */
875static 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(sem: &fw_device_rwsem); /* serialize config_rom access */
886 spin_lock_irq(lock: &card->lock); /* serialize node access */
887
888 if (memcmp(p: old->config_rom, q: new->config_rom, size: 6 * 4) == 0 &&
889 atomic_cmpxchg(v: &old->state,
890 old: FW_DEVICE_GONE,
891 new: 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, fmt: "rediscovered device %s\n", dev_name(dev));
906
907 old->workfn = fw_device_update;
908 fw_schedule_device_work(device: old, delay: 0);
909
910 if (current_node == card->root_node)
911 fw_schedule_bm_work(card, delay: 0);
912
913 match = 1;
914 }
915
916 spin_unlock_irq(lock: &card->lock);
917 up_read(sem: &fw_device_rwsem);
918
919 return match;
920}
921
922enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
923
924static 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 destination_id: device->node_id, generation, speed: device->max_speed,
950 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
951 payload: &data, length: 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 destination_id: device->node_id, generation, speed: device->max_speed,
969 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
970 payload: &data, length: 4);
971 }
972}
973
974int fw_device_set_broadcast_channel(struct device *dev, void *gen)
975{
976 if (is_fw_device(dev))
977 set_broadcast_channel(fw_device(dev), generation: (long)gen);
978
979 return 0;
980}
981
982static 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, generation: device->generation);
997 if (ret != RCODE_COMPLETE) {
998 if (device->config_rom_retries < MAX_RETRIES &&
999 atomic_read(v: &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, fmt: "giving up on node %x: reading config rom failed: %s\n",
1005 device->node_id,
1006 fw_rcode_string(rcode: ret));
1007 if (device->node == card->root_node)
1008 fw_schedule_bm_work(card, delay: 0);
1009 fw_device_release(dev: &device->device);
1010 }
1011 return;
1012 }
1013
1014 revived_dev = device_find_child(dev: card->device,
1015 data: device, match: lookup_existing_device);
1016 if (revived_dev) {
1017 put_device(dev: revived_dev);
1018 fw_device_release(dev: &device->device);
1019
1020 return;
1021 }
1022
1023 device_initialize(dev: &device->device);
1024
1025 fw_device_get(device);
1026 down_write(sem: &fw_device_rwsem);
1027 minor = idr_alloc(&fw_device_idr, ptr: device, start: 0, end: 1 << MINORBITS,
1028 GFP_KERNEL);
1029 up_write(sem: &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(dev: &device->device, name: "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(dev: &device->device,
1044 attrs: fw_device_attributes,
1045 group: &device->attribute_group);
1046
1047 if (device_add(dev: &device->device)) {
1048 fw_err(card, fmt: "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(v: &device->state,
1064 old: FW_DEVICE_INITIALIZING,
1065 new: 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, fmt: "created device %s: GUID %08x%08x, S%d00\n",
1070 dev_name(dev: &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, generation: device->generation);
1076
1077 add_device_randomness(buf: &device->config_rom[3], len: 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, delay: 0);
1088
1089 return;
1090
1091 error_with_cdev:
1092 down_write(sem: &fw_device_rwsem);
1093 idr_remove(&fw_device_idr, id: minor);
1094 up_write(sem: &fw_device_rwsem);
1095 error:
1096 fw_device_put(device); /* fw_device_idr's reference */
1097
1098 put_device(dev: &device->device); /* our reference */
1099}
1100
1101/* Reread and compare bus info block and header of root directory */
1102static 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, index: i, data: &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
1127static 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, generation: device->generation, changed: &changed);
1136 if (ret != RCODE_COMPLETE)
1137 goto failed_config_rom;
1138
1139 if (!changed) {
1140 if (atomic_cmpxchg(v: &device->state,
1141 old: FW_DEVICE_INITIALIZING,
1142 new: 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(dev: &device->device, NULL, fn: shutdown_unit);
1155
1156 ret = read_config_rom(device, generation: 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(kobj: &device->device.kobj, action: KOBJ_CHANGE);
1165
1166 if (atomic_cmpxchg(v: &device->state,
1167 old: FW_DEVICE_INITIALIZING,
1168 new: FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1169 goto gone;
1170
1171 fw_notice(card, fmt: "refreshed device %s\n", dev_name(dev: &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(v: &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, fmt: "giving up on refresh of device %s: %s\n",
1184 dev_name(dev: &device->device), fw_rcode_string(rcode: ret));
1185 gone:
1186 atomic_set(v: &device->state, i: 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, delay: 0);
1192}
1193
1194static 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
1201void 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(size: 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(v: &device->state, i: 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(list: &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(v: &device->state,
1265 old: FW_DEVICE_RUNNING,
1266 new: FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1267 device->workfn = fw_device_refresh;
1268 fw_schedule_device_work(device,
1269 delay: 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(v: &device->state) == FW_DEVICE_RUNNING) {
1282 device->workfn = fw_device_update;
1283 fw_schedule_device_work(device, delay: 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(v: &device->state,
1306 new: FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1307 device->workfn = fw_device_shutdown;
1308 fw_schedule_device_work(device,
1309 delay: list_empty(head: &card->link) ? 0 : SHUTDOWN_DELAY);
1310 }
1311 break;
1312 }
1313}
1314

source code of linux/drivers/firewire/core-device.c