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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
4 */
5
6#include <linux/delay.h>
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/moduleparam.h>
10#include <linux/list.h>
11#include <linux/interrupt.h>
12#include <linux/spinlock.h>
13#include <linux/timer.h>
14#include <linux/device.h>
15#include <linux/slab.h>
16#include <linux/sched.h>
17#include <linux/kthread.h>
18#include <linux/freezer.h>
19#include <linux/hwmon.h>
20#include <linux/of.h>
21
22#include <linux/atomic.h>
23
24#include "w1_internal.h"
25#include "w1_netlink.h"
26
27#define W1_FAMILY_DEFAULT 0
28
29static int w1_timeout = 10;
30module_param_named(timeout, w1_timeout, int, 0);
31MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
32
33static int w1_timeout_us = 0;
34module_param_named(timeout_us, w1_timeout_us, int, 0);
35MODULE_PARM_DESC(timeout_us,
36 "time in microseconds between automatic slave searches");
37
38/* A search stops when w1_max_slave_count devices have been found in that
39 * search. The next search will start over and detect the same set of devices
40 * on a static 1-wire bus. Memory is not allocated based on this number, just
41 * on the number of devices known to the kernel. Having a high number does not
42 * consume additional resources. As a special case, if there is only one
43 * device on the network and w1_max_slave_count is set to 1, the device id can
44 * be read directly skipping the normal slower search process.
45 */
46int w1_max_slave_count = 64;
47module_param_named(max_slave_count, w1_max_slave_count, int, 0);
48MODULE_PARM_DESC(max_slave_count,
49 "maximum number of slaves detected in a search");
50
51int w1_max_slave_ttl = 10;
52module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
53MODULE_PARM_DESC(slave_ttl,
54 "Number of searches not seeing a slave before it will be removed");
55
56DEFINE_MUTEX(w1_mlock);
57LIST_HEAD(w1_masters);
58
59static int w1_master_match(struct device *dev, struct device_driver *drv)
60{
61 return 1;
62}
63
64static int w1_master_probe(struct device *dev)
65{
66 return -ENODEV;
67}
68
69static void w1_master_release(struct device *dev)
70{
71 struct w1_master *md = dev_to_w1_master(dev);
72
73 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
74 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
75 kfree(md);
76}
77
78static void w1_slave_release(struct device *dev)
79{
80 struct w1_slave *sl = dev_to_w1_slave(dev);
81
82 dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);
83
84 w1_family_put(sl->family);
85 sl->master->slave_count--;
86}
87
88static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
89{
90 struct w1_slave *sl = dev_to_w1_slave(dev);
91
92 return sprintf(buf, "%s\n", sl->name);
93}
94static DEVICE_ATTR_RO(name);
95
96static ssize_t id_show(struct device *dev,
97 struct device_attribute *attr, char *buf)
98{
99 struct w1_slave *sl = dev_to_w1_slave(dev);
100 ssize_t count = sizeof(sl->reg_num);
101
102 memcpy(buf, (u8 *)&sl->reg_num, count);
103 return count;
104}
105static DEVICE_ATTR_RO(id);
106
107static struct attribute *w1_slave_attrs[] = {
108 &dev_attr_name.attr,
109 &dev_attr_id.attr,
110 NULL,
111};
112ATTRIBUTE_GROUPS(w1_slave);
113
114/* Default family */
115
116static ssize_t rw_write(struct file *filp, struct kobject *kobj,
117 struct bin_attribute *bin_attr, char *buf, loff_t off,
118 size_t count)
119{
120 struct w1_slave *sl = kobj_to_w1_slave(kobj);
121
122 mutex_lock(&sl->master->mutex);
123 if (w1_reset_select_slave(sl)) {
124 count = 0;
125 goto out_up;
126 }
127
128 w1_write_block(sl->master, buf, count);
129
130out_up:
131 mutex_unlock(&sl->master->mutex);
132 return count;
133}
134
135static ssize_t rw_read(struct file *filp, struct kobject *kobj,
136 struct bin_attribute *bin_attr, char *buf, loff_t off,
137 size_t count)
138{
139 struct w1_slave *sl = kobj_to_w1_slave(kobj);
140
141 mutex_lock(&sl->master->mutex);
142 w1_read_block(sl->master, buf, count);
143 mutex_unlock(&sl->master->mutex);
144 return count;
145}
146
147static BIN_ATTR_RW(rw, PAGE_SIZE);
148
149static struct bin_attribute *w1_slave_bin_attrs[] = {
150 &bin_attr_rw,
151 NULL,
152};
153
154static const struct attribute_group w1_slave_default_group = {
155 .bin_attrs = w1_slave_bin_attrs,
156};
157
158static const struct attribute_group *w1_slave_default_groups[] = {
159 &w1_slave_default_group,
160 NULL,
161};
162
163static struct w1_family_ops w1_default_fops = {
164 .groups = w1_slave_default_groups,
165};
166
167static struct w1_family w1_default_family = {
168 .fops = &w1_default_fops,
169};
170
171static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
172
173static struct bus_type w1_bus_type = {
174 .name = "w1",
175 .match = w1_master_match,
176 .uevent = w1_uevent,
177};
178
179struct device_driver w1_master_driver = {
180 .name = "w1_master_driver",
181 .bus = &w1_bus_type,
182 .probe = w1_master_probe,
183};
184
185struct device w1_master_device = {
186 .parent = NULL,
187 .bus = &w1_bus_type,
188 .init_name = "w1 bus master",
189 .driver = &w1_master_driver,
190 .release = &w1_master_release
191};
192
193static struct device_driver w1_slave_driver = {
194 .name = "w1_slave_driver",
195 .bus = &w1_bus_type,
196};
197
198#if 0
199struct device w1_slave_device = {
200 .parent = NULL,
201 .bus = &w1_bus_type,
202 .init_name = "w1 bus slave",
203 .driver = &w1_slave_driver,
204 .release = &w1_slave_release
205};
206#endif /* 0 */
207
208static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
209{
210 struct w1_master *md = dev_to_w1_master(dev);
211 ssize_t count;
212
213 mutex_lock(&md->mutex);
214 count = sprintf(buf, "%s\n", md->name);
215 mutex_unlock(&md->mutex);
216
217 return count;
218}
219
220static ssize_t w1_master_attribute_store_search(struct device * dev,
221 struct device_attribute *attr,
222 const char * buf, size_t count)
223{
224 long tmp;
225 struct w1_master *md = dev_to_w1_master(dev);
226 int ret;
227
228 ret = kstrtol(buf, 0, &tmp);
229 if (ret)
230 return ret;
231
232 mutex_lock(&md->mutex);
233 md->search_count = tmp;
234 mutex_unlock(&md->mutex);
235 /* Only wake if it is going to be searching. */
236 if (tmp)
237 wake_up_process(md->thread);
238
239 return count;
240}
241
242static ssize_t w1_master_attribute_show_search(struct device *dev,
243 struct device_attribute *attr,
244 char *buf)
245{
246 struct w1_master *md = dev_to_w1_master(dev);
247 ssize_t count;
248
249 mutex_lock(&md->mutex);
250 count = sprintf(buf, "%d\n", md->search_count);
251 mutex_unlock(&md->mutex);
252
253 return count;
254}
255
256static ssize_t w1_master_attribute_store_pullup(struct device *dev,
257 struct device_attribute *attr,
258 const char *buf, size_t count)
259{
260 long tmp;
261 struct w1_master *md = dev_to_w1_master(dev);
262 int ret;
263
264 ret = kstrtol(buf, 0, &tmp);
265 if (ret)
266 return ret;
267
268 mutex_lock(&md->mutex);
269 md->enable_pullup = tmp;
270 mutex_unlock(&md->mutex);
271
272 return count;
273}
274
275static ssize_t w1_master_attribute_show_pullup(struct device *dev,
276 struct device_attribute *attr,
277 char *buf)
278{
279 struct w1_master *md = dev_to_w1_master(dev);
280 ssize_t count;
281
282 mutex_lock(&md->mutex);
283 count = sprintf(buf, "%d\n", md->enable_pullup);
284 mutex_unlock(&md->mutex);
285
286 return count;
287}
288
289static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
290{
291 struct w1_master *md = dev_to_w1_master(dev);
292 ssize_t count;
293
294 mutex_lock(&md->mutex);
295 count = sprintf(buf, "0x%p\n", md->bus_master);
296 mutex_unlock(&md->mutex);
297 return count;
298}
299
300static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
301{
302 ssize_t count;
303 count = sprintf(buf, "%d\n", w1_timeout);
304 return count;
305}
306
307static ssize_t w1_master_attribute_show_timeout_us(struct device *dev,
308 struct device_attribute *attr, char *buf)
309{
310 ssize_t count;
311 count = sprintf(buf, "%d\n", w1_timeout_us);
312 return count;
313}
314
315static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,
316 struct device_attribute *attr, const char *buf, size_t count)
317{
318 int tmp;
319 struct w1_master *md = dev_to_w1_master(dev);
320
321 if (kstrtoint(buf, 0, &tmp) || tmp < 1)
322 return -EINVAL;
323
324 mutex_lock(&md->mutex);
325 md->max_slave_count = tmp;
326 /* allow each time the max_slave_count is updated */
327 clear_bit(W1_WARN_MAX_COUNT, &md->flags);
328 mutex_unlock(&md->mutex);
329
330 return count;
331}
332
333static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
334{
335 struct w1_master *md = dev_to_w1_master(dev);
336 ssize_t count;
337
338 mutex_lock(&md->mutex);
339 count = sprintf(buf, "%d\n", md->max_slave_count);
340 mutex_unlock(&md->mutex);
341 return count;
342}
343
344static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
345{
346 struct w1_master *md = dev_to_w1_master(dev);
347 ssize_t count;
348
349 mutex_lock(&md->mutex);
350 count = sprintf(buf, "%lu\n", md->attempts);
351 mutex_unlock(&md->mutex);
352 return count;
353}
354
355static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
356{
357 struct w1_master *md = dev_to_w1_master(dev);
358 ssize_t count;
359
360 mutex_lock(&md->mutex);
361 count = sprintf(buf, "%d\n", md->slave_count);
362 mutex_unlock(&md->mutex);
363 return count;
364}
365
366static ssize_t w1_master_attribute_show_slaves(struct device *dev,
367 struct device_attribute *attr, char *buf)
368{
369 struct w1_master *md = dev_to_w1_master(dev);
370 int c = PAGE_SIZE;
371 struct list_head *ent, *n;
372 struct w1_slave *sl = NULL;
373
374 mutex_lock(&md->list_mutex);
375
376 list_for_each_safe(ent, n, &md->slist) {
377 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
378
379 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
380 }
381 if (!sl)
382 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
383
384 mutex_unlock(&md->list_mutex);
385
386 return PAGE_SIZE - c;
387}
388
389static ssize_t w1_master_attribute_show_add(struct device *dev,
390 struct device_attribute *attr, char *buf)
391{
392 int c = PAGE_SIZE;
393 c -= snprintf(buf+PAGE_SIZE - c, c,
394 "write device id xx-xxxxxxxxxxxx to add slave\n");
395 return PAGE_SIZE - c;
396}
397
398static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
399 struct w1_reg_num *rn)
400{
401 unsigned int family;
402 unsigned long long id;
403 int i;
404 u64 rn64_le;
405
406 /* The CRC value isn't read from the user because the sysfs directory
407 * doesn't include it and most messages from the bus search don't
408 * print it either. It would be unreasonable for the user to then
409 * provide it.
410 */
411 const char *error_msg = "bad slave string format, expecting "
412 "ff-dddddddddddd\n";
413
414 if (buf[2] != '-') {
415 dev_err(dev, "%s", error_msg);
416 return -EINVAL;
417 }
418 i = sscanf(buf, "%02x-%012llx", &family, &id);
419 if (i != 2) {
420 dev_err(dev, "%s", error_msg);
421 return -EINVAL;
422 }
423 rn->family = family;
424 rn->id = id;
425
426 rn64_le = cpu_to_le64(*(u64 *)rn);
427 rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
428
429#if 0
430 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
431 rn->family, (unsigned long long)rn->id, rn->crc);
432#endif
433
434 return 0;
435}
436
437/* Searches the slaves in the w1_master and returns a pointer or NULL.
438 * Note: must not hold list_mutex
439 */
440struct w1_slave *w1_slave_search_device(struct w1_master *dev,
441 struct w1_reg_num *rn)
442{
443 struct w1_slave *sl;
444 mutex_lock(&dev->list_mutex);
445 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
446 if (sl->reg_num.family == rn->family &&
447 sl->reg_num.id == rn->id &&
448 sl->reg_num.crc == rn->crc) {
449 mutex_unlock(&dev->list_mutex);
450 return sl;
451 }
452 }
453 mutex_unlock(&dev->list_mutex);
454 return NULL;
455}
456
457static ssize_t w1_master_attribute_store_add(struct device *dev,
458 struct device_attribute *attr,
459 const char *buf, size_t count)
460{
461 struct w1_master *md = dev_to_w1_master(dev);
462 struct w1_reg_num rn;
463 struct w1_slave *sl;
464 ssize_t result = count;
465
466 if (w1_atoreg_num(dev, buf, count, &rn))
467 return -EINVAL;
468
469 mutex_lock(&md->mutex);
470 sl = w1_slave_search_device(md, &rn);
471 /* It would be nice to do a targeted search one the one-wire bus
472 * for the new device to see if it is out there or not. But the
473 * current search doesn't support that.
474 */
475 if (sl) {
476 dev_info(dev, "Device %s already exists\n", sl->name);
477 result = -EINVAL;
478 } else {
479 w1_attach_slave_device(md, &rn);
480 }
481 mutex_unlock(&md->mutex);
482
483 return result;
484}
485
486static ssize_t w1_master_attribute_show_remove(struct device *dev,
487 struct device_attribute *attr, char *buf)
488{
489 int c = PAGE_SIZE;
490 c -= snprintf(buf+PAGE_SIZE - c, c,
491 "write device id xx-xxxxxxxxxxxx to remove slave\n");
492 return PAGE_SIZE - c;
493}
494
495static ssize_t w1_master_attribute_store_remove(struct device *dev,
496 struct device_attribute *attr,
497 const char *buf, size_t count)
498{
499 struct w1_master *md = dev_to_w1_master(dev);
500 struct w1_reg_num rn;
501 struct w1_slave *sl;
502 ssize_t result = count;
503
504 if (w1_atoreg_num(dev, buf, count, &rn))
505 return -EINVAL;
506
507 mutex_lock(&md->mutex);
508 sl = w1_slave_search_device(md, &rn);
509 if (sl) {
510 result = w1_slave_detach(sl);
511 /* refcnt 0 means it was detached in the call */
512 if (result == 0)
513 result = count;
514 } else {
515 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
516 (unsigned long long)rn.id);
517 result = -EINVAL;
518 }
519 mutex_unlock(&md->mutex);
520
521 return result;
522}
523
524#define W1_MASTER_ATTR_RO(_name, _mode) \
525 struct device_attribute w1_master_attribute_##_name = \
526 __ATTR(w1_master_##_name, _mode, \
527 w1_master_attribute_show_##_name, NULL)
528
529#define W1_MASTER_ATTR_RW(_name, _mode) \
530 struct device_attribute w1_master_attribute_##_name = \
531 __ATTR(w1_master_##_name, _mode, \
532 w1_master_attribute_show_##_name, \
533 w1_master_attribute_store_##_name)
534
535static W1_MASTER_ATTR_RO(name, S_IRUGO);
536static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
537static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
538static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);
539static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
540static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
541static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO);
542static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
543static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
544static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
545static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
546static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
547
548static struct attribute *w1_master_default_attrs[] = {
549 &w1_master_attribute_name.attr,
550 &w1_master_attribute_slaves.attr,
551 &w1_master_attribute_slave_count.attr,
552 &w1_master_attribute_max_slave_count.attr,
553 &w1_master_attribute_attempts.attr,
554 &w1_master_attribute_timeout.attr,
555 &w1_master_attribute_timeout_us.attr,
556 &w1_master_attribute_pointer.attr,
557 &w1_master_attribute_search.attr,
558 &w1_master_attribute_pullup.attr,
559 &w1_master_attribute_add.attr,
560 &w1_master_attribute_remove.attr,
561 NULL
562};
563
564static const struct attribute_group w1_master_defattr_group = {
565 .attrs = w1_master_default_attrs,
566};
567
568int w1_create_master_attributes(struct w1_master *master)
569{
570 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
571}
572
573void w1_destroy_master_attributes(struct w1_master *master)
574{
575 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
576}
577
578static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
579{
580 struct w1_master *md = NULL;
581 struct w1_slave *sl = NULL;
582 char *event_owner, *name;
583 int err = 0;
584
585 if (dev->driver == &w1_master_driver) {
586 md = container_of(dev, struct w1_master, dev);
587 event_owner = "master";
588 name = md->name;
589 } else if (dev->driver == &w1_slave_driver) {
590 sl = container_of(dev, struct w1_slave, dev);
591 event_owner = "slave";
592 name = sl->name;
593 } else {
594 dev_dbg(dev, "Unknown event.\n");
595 return -EINVAL;
596 }
597
598 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
599 event_owner, name, dev_name(dev));
600
601 if (dev->driver != &w1_slave_driver || !sl)
602 goto end;
603
604 err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
605 if (err)
606 goto end;
607
608 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
609 (unsigned long long)sl->reg_num.id);
610end:
611 return err;
612}
613
614static int w1_family_notify(unsigned long action, struct w1_slave *sl)
615{
616 struct w1_family_ops *fops;
617 int err;
618
619 fops = sl->family->fops;
620
621 if (!fops)
622 return 0;
623
624 switch (action) {
625 case BUS_NOTIFY_ADD_DEVICE:
626 /* if the family driver needs to initialize something... */
627 if (fops->add_slave) {
628 err = fops->add_slave(sl);
629 if (err < 0) {
630 dev_err(&sl->dev,
631 "add_slave() call failed. err=%d\n",
632 err);
633 return err;
634 }
635 }
636 if (fops->groups) {
637 err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
638 if (err) {
639 dev_err(&sl->dev,
640 "sysfs group creation failed. err=%d\n",
641 err);
642 return err;
643 }
644 }
645 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info) {
646 struct device *hwmon
647 = hwmon_device_register_with_info(&sl->dev,
648 "w1_slave_temp", sl,
649 fops->chip_info,
650 NULL);
651 if (IS_ERR(hwmon)) {
652 dev_warn(&sl->dev,
653 "could not create hwmon device\n");
654 } else {
655 sl->hwmon = hwmon;
656 }
657 }
658 break;
659 case BUS_NOTIFY_DEL_DEVICE:
660 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info &&
661 sl->hwmon)
662 hwmon_device_unregister(sl->hwmon);
663 if (fops->remove_slave)
664 sl->family->fops->remove_slave(sl);
665 if (fops->groups)
666 sysfs_remove_groups(&sl->dev.kobj, fops->groups);
667 break;
668 }
669 return 0;
670}
671
672static int __w1_attach_slave_device(struct w1_slave *sl)
673{
674 int err;
675
676 sl->dev.parent = &sl->master->dev;
677 sl->dev.driver = &w1_slave_driver;
678 sl->dev.bus = &w1_bus_type;
679 sl->dev.release = &w1_slave_release;
680 sl->dev.groups = w1_slave_groups;
681 sl->dev.of_node = of_find_matching_node(sl->master->dev.of_node,
682 sl->family->of_match_table);
683
684 dev_set_name(&sl->dev, "%02x-%012llx",
685 (unsigned int) sl->reg_num.family,
686 (unsigned long long) sl->reg_num.id);
687 snprintf(&sl->name[0], sizeof(sl->name),
688 "%02x-%012llx",
689 (unsigned int) sl->reg_num.family,
690 (unsigned long long) sl->reg_num.id);
691
692 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
693 dev_name(&sl->dev), sl);
694
695 /* suppress for w1_family_notify before sending KOBJ_ADD */
696 dev_set_uevent_suppress(&sl->dev, true);
697
698 err = device_register(&sl->dev);
699 if (err < 0) {
700 dev_err(&sl->dev,
701 "Device registration [%s] failed. err=%d\n",
702 dev_name(&sl->dev), err);
703 put_device(&sl->dev);
704 return err;
705 }
706 w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl);
707
708 dev_set_uevent_suppress(&sl->dev, false);
709 kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
710
711 mutex_lock(&sl->master->list_mutex);
712 list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
713 mutex_unlock(&sl->master->list_mutex);
714
715 return 0;
716}
717
718int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
719{
720 struct w1_slave *sl;
721 struct w1_family *f;
722 int err;
723 struct w1_netlink_msg msg;
724
725 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
726 if (!sl) {
727 dev_err(&dev->dev,
728 "%s: failed to allocate new slave device.\n",
729 __func__);
730 return -ENOMEM;
731 }
732
733
734 sl->owner = THIS_MODULE;
735 sl->master = dev;
736 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
737
738 memset(&msg, 0, sizeof(msg));
739 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
740 atomic_set(&sl->refcnt, 1);
741 atomic_inc(&sl->master->refcnt);
742 dev->slave_count++;
743 dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",
744 rn->family, (unsigned long long)rn->id, rn->crc);
745
746 /* slave modules need to be loaded in a context with unlocked mutex */
747 mutex_unlock(&dev->mutex);
748 request_module("w1-family-0x%02X", rn->family);
749 mutex_lock(&dev->mutex);
750
751 spin_lock(&w1_flock);
752 f = w1_family_registered(rn->family);
753 if (!f) {
754 f= &w1_default_family;
755 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
756 rn->family, rn->family,
757 (unsigned long long)rn->id, rn->crc);
758 }
759 __w1_family_get(f);
760 spin_unlock(&w1_flock);
761
762 sl->family = f;
763
764 err = __w1_attach_slave_device(sl);
765 if (err < 0) {
766 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
767 sl->name);
768 dev->slave_count--;
769 w1_family_put(sl->family);
770 atomic_dec(&sl->master->refcnt);
771 kfree(sl);
772 return err;
773 }
774
775 sl->ttl = dev->slave_ttl;
776
777 memcpy(msg.id.id, rn, sizeof(msg.id));
778 msg.type = W1_SLAVE_ADD;
779 w1_netlink_send(dev, &msg);
780
781 return 0;
782}
783
784int w1_unref_slave(struct w1_slave *sl)
785{
786 struct w1_master *dev = sl->master;
787 int refcnt;
788 mutex_lock(&dev->list_mutex);
789 refcnt = atomic_sub_return(1, &sl->refcnt);
790 if (refcnt == 0) {
791 struct w1_netlink_msg msg;
792
793 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
794 sl->name, sl);
795
796 list_del(&sl->w1_slave_entry);
797
798 memset(&msg, 0, sizeof(msg));
799 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
800 msg.type = W1_SLAVE_REMOVE;
801 w1_netlink_send(sl->master, &msg);
802
803 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);
804 device_unregister(&sl->dev);
805 #ifdef DEBUG
806 memset(sl, 0, sizeof(*sl));
807 #endif
808 kfree(sl);
809 }
810 atomic_dec(&dev->refcnt);
811 mutex_unlock(&dev->list_mutex);
812 return refcnt;
813}
814
815int w1_slave_detach(struct w1_slave *sl)
816{
817 /* Only detach a slave once as it decreases the refcnt each time. */
818 int destroy_now;
819 mutex_lock(&sl->master->list_mutex);
820 destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
821 set_bit(W1_SLAVE_DETACH, &sl->flags);
822 mutex_unlock(&sl->master->list_mutex);
823
824 if (destroy_now)
825 destroy_now = !w1_unref_slave(sl);
826 return destroy_now ? 0 : -EBUSY;
827}
828
829struct w1_master *w1_search_master_id(u32 id)
830{
831 struct w1_master *dev;
832 int found = 0;
833
834 mutex_lock(&w1_mlock);
835 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
836 if (dev->id == id) {
837 found = 1;
838 atomic_inc(&dev->refcnt);
839 break;
840 }
841 }
842 mutex_unlock(&w1_mlock);
843
844 return (found)?dev:NULL;
845}
846
847struct w1_slave *w1_search_slave(struct w1_reg_num *id)
848{
849 struct w1_master *dev;
850 struct w1_slave *sl = NULL;
851 int found = 0;
852
853 mutex_lock(&w1_mlock);
854 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
855 mutex_lock(&dev->list_mutex);
856 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
857 if (sl->reg_num.family == id->family &&
858 sl->reg_num.id == id->id &&
859 sl->reg_num.crc == id->crc) {
860 found = 1;
861 atomic_inc(&dev->refcnt);
862 atomic_inc(&sl->refcnt);
863 break;
864 }
865 }
866 mutex_unlock(&dev->list_mutex);
867
868 if (found)
869 break;
870 }
871 mutex_unlock(&w1_mlock);
872
873 return (found)?sl:NULL;
874}
875
876void w1_reconnect_slaves(struct w1_family *f, int attach)
877{
878 struct w1_slave *sl, *sln;
879 struct w1_master *dev;
880
881 mutex_lock(&w1_mlock);
882 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
883 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
884 "for family %02x.\n", dev->name, f->fid);
885 mutex_lock(&dev->mutex);
886 mutex_lock(&dev->list_mutex);
887 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
888 /* If it is a new family, slaves with the default
889 * family driver and are that family will be
890 * connected. If the family is going away, devices
891 * matching that family are reconneced.
892 */
893 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
894 && sl->reg_num.family == f->fid) ||
895 (!attach && sl->family->fid == f->fid)) {
896 struct w1_reg_num rn;
897
898 mutex_unlock(&dev->list_mutex);
899 memcpy(&rn, &sl->reg_num, sizeof(rn));
900 /* If it was already in use let the automatic
901 * scan pick it up again later.
902 */
903 if (!w1_slave_detach(sl))
904 w1_attach_slave_device(dev, &rn);
905 mutex_lock(&dev->list_mutex);
906 }
907 }
908 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
909 "has been finished.\n", dev->name);
910 mutex_unlock(&dev->list_mutex);
911 mutex_unlock(&dev->mutex);
912 }
913 mutex_unlock(&w1_mlock);
914}
915
916void w1_slave_found(struct w1_master *dev, u64 rn)
917{
918 struct w1_slave *sl;
919 struct w1_reg_num *tmp;
920 u64 rn_le = cpu_to_le64(rn);
921
922 atomic_inc(&dev->refcnt);
923
924 tmp = (struct w1_reg_num *) &rn;
925
926 sl = w1_slave_search_device(dev, tmp);
927 if (sl) {
928 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
929 } else {
930 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
931 w1_attach_slave_device(dev, tmp);
932 }
933
934 atomic_dec(&dev->refcnt);
935}
936
937/**
938 * w1_search() - Performs a ROM Search & registers any devices found.
939 * @dev: The master device to search
940 * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH
941 * to return only devices in the alarmed state
942 * @cb: Function to call when a device is found
943 *
944 * The 1-wire search is a simple binary tree search.
945 * For each bit of the address, we read two bits and write one bit.
946 * The bit written will put to sleep all devies that don't match that bit.
947 * When the two reads differ, the direction choice is obvious.
948 * When both bits are 0, we must choose a path to take.
949 * When we can scan all 64 bits without having to choose a path, we are done.
950 *
951 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
952 *
953 */
954void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
955{
956 u64 last_rn, rn, tmp64;
957 int i, slave_count = 0;
958 int last_zero, last_device;
959 int search_bit, desc_bit;
960 u8 triplet_ret = 0;
961
962 search_bit = 0;
963 rn = dev->search_id;
964 last_rn = 0;
965 last_device = 0;
966 last_zero = -1;
967
968 desc_bit = 64;
969
970 while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
971 last_rn = rn;
972 rn = 0;
973
974 /*
975 * Reset bus and all 1-wire device state machines
976 * so they can respond to our requests.
977 *
978 * Return 0 - device(s) present, 1 - no devices present.
979 */
980 mutex_lock(&dev->bus_mutex);
981 if (w1_reset_bus(dev)) {
982 mutex_unlock(&dev->bus_mutex);
983 dev_dbg(&dev->dev, "No devices present on the wire.\n");
984 break;
985 }
986
987 /* Do fast search on single slave bus */
988 if (dev->max_slave_count == 1) {
989 int rv;
990 w1_write_8(dev, W1_READ_ROM);
991 rv = w1_read_block(dev, (u8 *)&rn, 8);
992 mutex_unlock(&dev->bus_mutex);
993
994 if (rv == 8 && rn)
995 cb(dev, rn);
996
997 break;
998 }
999
1000 /* Start the search */
1001 w1_write_8(dev, search_type);
1002 for (i = 0; i < 64; ++i) {
1003 /* Determine the direction/search bit */
1004 if (i == desc_bit)
1005 search_bit = 1; /* took the 0 path last time, so take the 1 path */
1006 else if (i > desc_bit)
1007 search_bit = 0; /* take the 0 path on the next branch */
1008 else
1009 search_bit = ((last_rn >> i) & 0x1);
1010
1011 /* Read two bits and write one bit */
1012 triplet_ret = w1_triplet(dev, search_bit);
1013
1014 /* quit if no device responded */
1015 if ( (triplet_ret & 0x03) == 0x03 )
1016 break;
1017
1018 /* If both directions were valid, and we took the 0 path... */
1019 if (triplet_ret == 0)
1020 last_zero = i;
1021
1022 /* extract the direction taken & update the device number */
1023 tmp64 = (triplet_ret >> 2);
1024 rn |= (tmp64 << i);
1025
1026 if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
1027 mutex_unlock(&dev->bus_mutex);
1028 dev_dbg(&dev->dev, "Abort w1_search\n");
1029 return;
1030 }
1031 }
1032 mutex_unlock(&dev->bus_mutex);
1033
1034 if ( (triplet_ret & 0x03) != 0x03 ) {
1035 if ((desc_bit == last_zero) || (last_zero < 0)) {
1036 last_device = 1;
1037 dev->search_id = 0;
1038 } else {
1039 dev->search_id = rn;
1040 }
1041 desc_bit = last_zero;
1042 cb(dev, rn);
1043 }
1044
1045 if (!last_device && slave_count == dev->max_slave_count &&
1046 !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
1047 /* Only max_slave_count will be scanned in a search,
1048 * but it will start where it left off next search
1049 * until all ids are identified and then it will start
1050 * over. A continued search will report the previous
1051 * last id as the first id (provided it is still on the
1052 * bus).
1053 */
1054 dev_info(&dev->dev, "%s: max_slave_count %d reached, "
1055 "will continue next search.\n", __func__,
1056 dev->max_slave_count);
1057 set_bit(W1_WARN_MAX_COUNT, &dev->flags);
1058 }
1059 }
1060}
1061
1062void w1_search_process_cb(struct w1_master *dev, u8 search_type,
1063 w1_slave_found_callback cb)
1064{
1065 struct w1_slave *sl, *sln;
1066
1067 mutex_lock(&dev->list_mutex);
1068 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
1069 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
1070 mutex_unlock(&dev->list_mutex);
1071
1072 w1_search_devices(dev, search_type, cb);
1073
1074 mutex_lock(&dev->list_mutex);
1075 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
1076 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
1077 mutex_unlock(&dev->list_mutex);
1078 w1_slave_detach(sl);
1079 mutex_lock(&dev->list_mutex);
1080 }
1081 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
1082 sl->ttl = dev->slave_ttl;
1083 }
1084 mutex_unlock(&dev->list_mutex);
1085
1086 if (dev->search_count > 0)
1087 dev->search_count--;
1088}
1089
1090static void w1_search_process(struct w1_master *dev, u8 search_type)
1091{
1092 w1_search_process_cb(dev, search_type, w1_slave_found);
1093}
1094
1095/**
1096 * w1_process_callbacks() - execute each dev->async_list callback entry
1097 * @dev: w1_master device
1098 *
1099 * The w1 master list_mutex must be held.
1100 *
1101 * Return: 1 if there were commands to executed 0 otherwise
1102 */
1103int w1_process_callbacks(struct w1_master *dev)
1104{
1105 int ret = 0;
1106 struct w1_async_cmd *async_cmd, *async_n;
1107
1108 /* The list can be added to in another thread, loop until it is empty */
1109 while (!list_empty(&dev->async_list)) {
1110 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
1111 async_entry) {
1112 /* drop the lock, if it is a search it can take a long
1113 * time */
1114 mutex_unlock(&dev->list_mutex);
1115 async_cmd->cb(dev, async_cmd);
1116 ret = 1;
1117 mutex_lock(&dev->list_mutex);
1118 }
1119 }
1120 return ret;
1121}
1122
1123int w1_process(void *data)
1124{
1125 struct w1_master *dev = (struct w1_master *) data;
1126 /* As long as w1_timeout is only set by a module parameter the sleep
1127 * time can be calculated in jiffies once.
1128 */
1129 const unsigned long jtime =
1130 usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);
1131 /* remainder if it woke up early */
1132 unsigned long jremain = 0;
1133
1134 for (;;) {
1135
1136 if (!jremain && dev->search_count) {
1137 mutex_lock(&dev->mutex);
1138 w1_search_process(dev, W1_SEARCH);
1139 mutex_unlock(&dev->mutex);
1140 }
1141
1142 mutex_lock(&dev->list_mutex);
1143 /* Note, w1_process_callback drops the lock while processing,
1144 * but locks it again before returning.
1145 */
1146 if (!w1_process_callbacks(dev) && jremain) {
1147 /* a wake up is either to stop the thread, process
1148 * callbacks, or search, it isn't process callbacks, so
1149 * schedule a search.
1150 */
1151 jremain = 1;
1152 }
1153
1154 __set_current_state(TASK_INTERRUPTIBLE);
1155
1156 /* hold list_mutex until after interruptible to prevent loosing
1157 * the wakeup signal when async_cmd is added.
1158 */
1159 mutex_unlock(&dev->list_mutex);
1160
1161 if (kthread_should_stop())
1162 break;
1163
1164 /* Only sleep when the search is active. */
1165 if (dev->search_count) {
1166 if (!jremain)
1167 jremain = jtime;
1168 jremain = schedule_timeout(jremain);
1169 }
1170 else
1171 schedule();
1172 }
1173
1174 atomic_dec(&dev->refcnt);
1175
1176 return 0;
1177}
1178
1179static int __init w1_init(void)
1180{
1181 int retval;
1182
1183 pr_info("Driver for 1-wire Dallas network protocol.\n");
1184
1185 w1_init_netlink();
1186
1187 retval = bus_register(&w1_bus_type);
1188 if (retval) {
1189 pr_err("Failed to register bus. err=%d.\n", retval);
1190 goto err_out_exit_init;
1191 }
1192
1193 retval = driver_register(&w1_master_driver);
1194 if (retval) {
1195 pr_err("Failed to register master driver. err=%d.\n",
1196 retval);
1197 goto err_out_bus_unregister;
1198 }
1199
1200 retval = driver_register(&w1_slave_driver);
1201 if (retval) {
1202 pr_err("Failed to register slave driver. err=%d.\n",
1203 retval);
1204 goto err_out_master_unregister;
1205 }
1206
1207 return 0;
1208
1209#if 0
1210/* For undoing the slave register if there was a step after it. */
1211err_out_slave_unregister:
1212 driver_unregister(&w1_slave_driver);
1213#endif
1214
1215err_out_master_unregister:
1216 driver_unregister(&w1_master_driver);
1217
1218err_out_bus_unregister:
1219 bus_unregister(&w1_bus_type);
1220
1221err_out_exit_init:
1222 return retval;
1223}
1224
1225static void __exit w1_fini(void)
1226{
1227 struct w1_master *dev;
1228
1229 /* Set netlink removal messages and some cleanup */
1230 list_for_each_entry(dev, &w1_masters, w1_master_entry)
1231 __w1_remove_master_device(dev);
1232
1233 w1_fini_netlink();
1234
1235 driver_unregister(&w1_slave_driver);
1236 driver_unregister(&w1_master_driver);
1237 bus_unregister(&w1_bus_type);
1238}
1239
1240module_init(w1_init);
1241module_exit(w1_fini);
1242
1243MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
1244MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
1245MODULE_LICENSE("GPL");
1/*
2 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15#include <linux/delay.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/list.h>
20#include <linux/interrupt.h>
21#include <linux/spinlock.h>
22#include <linux/timer.h>
23#include <linux/device.h>
24#include <linux/slab.h>
25#include <linux/sched.h>
26#include <linux/kthread.h>
27#include <linux/freezer.h>
28#include <linux/hwmon.h>
29
30#include <linux/atomic.h>
31
32#include "w1_internal.h"
33#include "w1_netlink.h"
34
35#define W1_FAMILY_DEFAULT 0
36
37static int w1_timeout = 10;
38module_param_named(timeout, w1_timeout, int, 0);
39MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
40
41static int w1_timeout_us = 0;
42module_param_named(timeout_us, w1_timeout_us, int, 0);
43MODULE_PARM_DESC(timeout_us,
44 "time in microseconds between automatic slave searches");
45
46/* A search stops when w1_max_slave_count devices have been found in that
47 * search. The next search will start over and detect the same set of devices
48 * on a static 1-wire bus. Memory is not allocated based on this number, just
49 * on the number of devices known to the kernel. Having a high number does not
50 * consume additional resources. As a special case, if there is only one
51 * device on the network and w1_max_slave_count is set to 1, the device id can
52 * be read directly skipping the normal slower search process.
53 */
54int w1_max_slave_count = 64;
55module_param_named(max_slave_count, w1_max_slave_count, int, 0);
56MODULE_PARM_DESC(max_slave_count,
57 "maximum number of slaves detected in a search");
58
59int w1_max_slave_ttl = 10;
60module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
61MODULE_PARM_DESC(slave_ttl,
62 "Number of searches not seeing a slave before it will be removed");
63
64DEFINE_MUTEX(w1_mlock);
65LIST_HEAD(w1_masters);
66
67static int w1_master_match(struct device *dev, struct device_driver *drv)
68{
69 return 1;
70}
71
72static int w1_master_probe(struct device *dev)
73{
74 return -ENODEV;
75}
76
77static void w1_master_release(struct device *dev)
78{
79 struct w1_master *md = dev_to_w1_master(dev);
80
81 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
82 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
83 kfree(md);
84}
85
86static void w1_slave_release(struct device *dev)
87{
88 struct w1_slave *sl = dev_to_w1_slave(dev);
89
90 dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);
91
92 w1_family_put(sl->family);
93 sl->master->slave_count--;
94}
95
96static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
97{
98 struct w1_slave *sl = dev_to_w1_slave(dev);
99
100 return sprintf(buf, "%s\n", sl->name);
101}
102static DEVICE_ATTR_RO(name);
103
104static ssize_t id_show(struct device *dev,
105 struct device_attribute *attr, char *buf)
106{
107 struct w1_slave *sl = dev_to_w1_slave(dev);
108 ssize_t count = sizeof(sl->reg_num);
109
110 memcpy(buf, (u8 *)&sl->reg_num, count);
111 return count;
112}
113static DEVICE_ATTR_RO(id);
114
115static struct attribute *w1_slave_attrs[] = {
116 &dev_attr_name.attr,
117 &dev_attr_id.attr,
118 NULL,
119};
120ATTRIBUTE_GROUPS(w1_slave);
121
122/* Default family */
123
124static ssize_t rw_write(struct file *filp, struct kobject *kobj,
125 struct bin_attribute *bin_attr, char *buf, loff_t off,
126 size_t count)
127{
128 struct w1_slave *sl = kobj_to_w1_slave(kobj);
129
130 mutex_lock(&sl->master->mutex);
131 if (w1_reset_select_slave(sl)) {
132 count = 0;
133 goto out_up;
134 }
135
136 w1_write_block(sl->master, buf, count);
137
138out_up:
139 mutex_unlock(&sl->master->mutex);
140 return count;
141}
142
143static ssize_t rw_read(struct file *filp, struct kobject *kobj,
144 struct bin_attribute *bin_attr, char *buf, loff_t off,
145 size_t count)
146{
147 struct w1_slave *sl = kobj_to_w1_slave(kobj);
148
149 mutex_lock(&sl->master->mutex);
150 w1_read_block(sl->master, buf, count);
151 mutex_unlock(&sl->master->mutex);
152 return count;
153}
154
155static BIN_ATTR_RW(rw, PAGE_SIZE);
156
157static struct bin_attribute *w1_slave_bin_attrs[] = {
158 &bin_attr_rw,
159 NULL,
160};
161
162static const struct attribute_group w1_slave_default_group = {
163 .bin_attrs = w1_slave_bin_attrs,
164};
165
166static const struct attribute_group *w1_slave_default_groups[] = {
167 &w1_slave_default_group,
168 NULL,
169};
170
171static struct w1_family_ops w1_default_fops = {
172 .groups = w1_slave_default_groups,
173};
174
175static struct w1_family w1_default_family = {
176 .fops = &w1_default_fops,
177};
178
179static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
180
181static struct bus_type w1_bus_type = {
182 .name = "w1",
183 .match = w1_master_match,
184 .uevent = w1_uevent,
185};
186
187struct device_driver w1_master_driver = {
188 .name = "w1_master_driver",
189 .bus = &w1_bus_type,
190 .probe = w1_master_probe,
191};
192
193struct device w1_master_device = {
194 .parent = NULL,
195 .bus = &w1_bus_type,
196 .init_name = "w1 bus master",
197 .driver = &w1_master_driver,
198 .release = &w1_master_release
199};
200
201static struct device_driver w1_slave_driver = {
202 .name = "w1_slave_driver",
203 .bus = &w1_bus_type,
204};
205
206#if 0
207struct device w1_slave_device = {
208 .parent = NULL,
209 .bus = &w1_bus_type,
210 .init_name = "w1 bus slave",
211 .driver = &w1_slave_driver,
212 .release = &w1_slave_release
213};
214#endif /* 0 */
215
216static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
217{
218 struct w1_master *md = dev_to_w1_master(dev);
219 ssize_t count;
220
221 mutex_lock(&md->mutex);
222 count = sprintf(buf, "%s\n", md->name);
223 mutex_unlock(&md->mutex);
224
225 return count;
226}
227
228static ssize_t w1_master_attribute_store_search(struct device * dev,
229 struct device_attribute *attr,
230 const char * buf, size_t count)
231{
232 long tmp;
233 struct w1_master *md = dev_to_w1_master(dev);
234 int ret;
235
236 ret = kstrtol(buf, 0, &tmp);
237 if (ret)
238 return ret;
239
240 mutex_lock(&md->mutex);
241 md->search_count = tmp;
242 mutex_unlock(&md->mutex);
243 /* Only wake if it is going to be searching. */
244 if (tmp)
245 wake_up_process(md->thread);
246
247 return count;
248}
249
250static ssize_t w1_master_attribute_show_search(struct device *dev,
251 struct device_attribute *attr,
252 char *buf)
253{
254 struct w1_master *md = dev_to_w1_master(dev);
255 ssize_t count;
256
257 mutex_lock(&md->mutex);
258 count = sprintf(buf, "%d\n", md->search_count);
259 mutex_unlock(&md->mutex);
260
261 return count;
262}
263
264static ssize_t w1_master_attribute_store_pullup(struct device *dev,
265 struct device_attribute *attr,
266 const char *buf, size_t count)
267{
268 long tmp;
269 struct w1_master *md = dev_to_w1_master(dev);
270 int ret;
271
272 ret = kstrtol(buf, 0, &tmp);
273 if (ret)
274 return ret;
275
276 mutex_lock(&md->mutex);
277 md->enable_pullup = tmp;
278 mutex_unlock(&md->mutex);
279
280 return count;
281}
282
283static ssize_t w1_master_attribute_show_pullup(struct device *dev,
284 struct device_attribute *attr,
285 char *buf)
286{
287 struct w1_master *md = dev_to_w1_master(dev);
288 ssize_t count;
289
290 mutex_lock(&md->mutex);
291 count = sprintf(buf, "%d\n", md->enable_pullup);
292 mutex_unlock(&md->mutex);
293
294 return count;
295}
296
297static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
298{
299 struct w1_master *md = dev_to_w1_master(dev);
300 ssize_t count;
301
302 mutex_lock(&md->mutex);
303 count = sprintf(buf, "0x%p\n", md->bus_master);
304 mutex_unlock(&md->mutex);
305 return count;
306}
307
308static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
309{
310 ssize_t count;
311 count = sprintf(buf, "%d\n", w1_timeout);
312 return count;
313}
314
315static ssize_t w1_master_attribute_show_timeout_us(struct device *dev,
316 struct device_attribute *attr, char *buf)
317{
318 ssize_t count;
319 count = sprintf(buf, "%d\n", w1_timeout_us);
320 return count;
321}
322
323static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,
324 struct device_attribute *attr, const char *buf, size_t count)
325{
326 int tmp;
327 struct w1_master *md = dev_to_w1_master(dev);
328
329 if (kstrtoint(buf, 0, &tmp) || tmp < 1)
330 return -EINVAL;
331
332 mutex_lock(&md->mutex);
333 md->max_slave_count = tmp;
334 /* allow each time the max_slave_count is updated */
335 clear_bit(W1_WARN_MAX_COUNT, &md->flags);
336 mutex_unlock(&md->mutex);
337
338 return count;
339}
340
341static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
342{
343 struct w1_master *md = dev_to_w1_master(dev);
344 ssize_t count;
345
346 mutex_lock(&md->mutex);
347 count = sprintf(buf, "%d\n", md->max_slave_count);
348 mutex_unlock(&md->mutex);
349 return count;
350}
351
352static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
353{
354 struct w1_master *md = dev_to_w1_master(dev);
355 ssize_t count;
356
357 mutex_lock(&md->mutex);
358 count = sprintf(buf, "%lu\n", md->attempts);
359 mutex_unlock(&md->mutex);
360 return count;
361}
362
363static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
364{
365 struct w1_master *md = dev_to_w1_master(dev);
366 ssize_t count;
367
368 mutex_lock(&md->mutex);
369 count = sprintf(buf, "%d\n", md->slave_count);
370 mutex_unlock(&md->mutex);
371 return count;
372}
373
374static ssize_t w1_master_attribute_show_slaves(struct device *dev,
375 struct device_attribute *attr, char *buf)
376{
377 struct w1_master *md = dev_to_w1_master(dev);
378 int c = PAGE_SIZE;
379 struct list_head *ent, *n;
380 struct w1_slave *sl = NULL;
381
382 mutex_lock(&md->list_mutex);
383
384 list_for_each_safe(ent, n, &md->slist) {
385 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
386
387 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
388 }
389 if (!sl)
390 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
391
392 mutex_unlock(&md->list_mutex);
393
394 return PAGE_SIZE - c;
395}
396
397static ssize_t w1_master_attribute_show_add(struct device *dev,
398 struct device_attribute *attr, char *buf)
399{
400 int c = PAGE_SIZE;
401 c -= snprintf(buf+PAGE_SIZE - c, c,
402 "write device id xx-xxxxxxxxxxxx to add slave\n");
403 return PAGE_SIZE - c;
404}
405
406static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
407 struct w1_reg_num *rn)
408{
409 unsigned int family;
410 unsigned long long id;
411 int i;
412 u64 rn64_le;
413
414 /* The CRC value isn't read from the user because the sysfs directory
415 * doesn't include it and most messages from the bus search don't
416 * print it either. It would be unreasonable for the user to then
417 * provide it.
418 */
419 const char *error_msg = "bad slave string format, expecting "
420 "ff-dddddddddddd\n";
421
422 if (buf[2] != '-') {
423 dev_err(dev, "%s", error_msg);
424 return -EINVAL;
425 }
426 i = sscanf(buf, "%02x-%012llx", &family, &id);
427 if (i != 2) {
428 dev_err(dev, "%s", error_msg);
429 return -EINVAL;
430 }
431 rn->family = family;
432 rn->id = id;
433
434 rn64_le = cpu_to_le64(*(u64 *)rn);
435 rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
436
437#if 0
438 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
439 rn->family, (unsigned long long)rn->id, rn->crc);
440#endif
441
442 return 0;
443}
444
445/* Searches the slaves in the w1_master and returns a pointer or NULL.
446 * Note: must not hold list_mutex
447 */
448struct w1_slave *w1_slave_search_device(struct w1_master *dev,
449 struct w1_reg_num *rn)
450{
451 struct w1_slave *sl;
452 mutex_lock(&dev->list_mutex);
453 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
454 if (sl->reg_num.family == rn->family &&
455 sl->reg_num.id == rn->id &&
456 sl->reg_num.crc == rn->crc) {
457 mutex_unlock(&dev->list_mutex);
458 return sl;
459 }
460 }
461 mutex_unlock(&dev->list_mutex);
462 return NULL;
463}
464
465static ssize_t w1_master_attribute_store_add(struct device *dev,
466 struct device_attribute *attr,
467 const char *buf, size_t count)
468{
469 struct w1_master *md = dev_to_w1_master(dev);
470 struct w1_reg_num rn;
471 struct w1_slave *sl;
472 ssize_t result = count;
473
474 if (w1_atoreg_num(dev, buf, count, &rn))
475 return -EINVAL;
476
477 mutex_lock(&md->mutex);
478 sl = w1_slave_search_device(md, &rn);
479 /* It would be nice to do a targeted search one the one-wire bus
480 * for the new device to see if it is out there or not. But the
481 * current search doesn't support that.
482 */
483 if (sl) {
484 dev_info(dev, "Device %s already exists\n", sl->name);
485 result = -EINVAL;
486 } else {
487 w1_attach_slave_device(md, &rn);
488 }
489 mutex_unlock(&md->mutex);
490
491 return result;
492}
493
494static ssize_t w1_master_attribute_show_remove(struct device *dev,
495 struct device_attribute *attr, char *buf)
496{
497 int c = PAGE_SIZE;
498 c -= snprintf(buf+PAGE_SIZE - c, c,
499 "write device id xx-xxxxxxxxxxxx to remove slave\n");
500 return PAGE_SIZE - c;
501}
502
503static ssize_t w1_master_attribute_store_remove(struct device *dev,
504 struct device_attribute *attr,
505 const char *buf, size_t count)
506{
507 struct w1_master *md = dev_to_w1_master(dev);
508 struct w1_reg_num rn;
509 struct w1_slave *sl;
510 ssize_t result = count;
511
512 if (w1_atoreg_num(dev, buf, count, &rn))
513 return -EINVAL;
514
515 mutex_lock(&md->mutex);
516 sl = w1_slave_search_device(md, &rn);
517 if (sl) {
518 result = w1_slave_detach(sl);
519 /* refcnt 0 means it was detached in the call */
520 if (result == 0)
521 result = count;
522 } else {
523 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
524 (unsigned long long)rn.id);
525 result = -EINVAL;
526 }
527 mutex_unlock(&md->mutex);
528
529 return result;
530}
531
532#define W1_MASTER_ATTR_RO(_name, _mode) \
533 struct device_attribute w1_master_attribute_##_name = \
534 __ATTR(w1_master_##_name, _mode, \
535 w1_master_attribute_show_##_name, NULL)
536
537#define W1_MASTER_ATTR_RW(_name, _mode) \
538 struct device_attribute w1_master_attribute_##_name = \
539 __ATTR(w1_master_##_name, _mode, \
540 w1_master_attribute_show_##_name, \
541 w1_master_attribute_store_##_name)
542
543static W1_MASTER_ATTR_RO(name, S_IRUGO);
544static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
545static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
546static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);
547static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
548static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
549static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO);
550static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
551static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
552static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
553static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
554static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
555
556static struct attribute *w1_master_default_attrs[] = {
557 &w1_master_attribute_name.attr,
558 &w1_master_attribute_slaves.attr,
559 &w1_master_attribute_slave_count.attr,
560 &w1_master_attribute_max_slave_count.attr,
561 &w1_master_attribute_attempts.attr,
562 &w1_master_attribute_timeout.attr,
563 &w1_master_attribute_timeout_us.attr,
564 &w1_master_attribute_pointer.attr,
565 &w1_master_attribute_search.attr,
566 &w1_master_attribute_pullup.attr,
567 &w1_master_attribute_add.attr,
568 &w1_master_attribute_remove.attr,
569 NULL
570};
571
572static const struct attribute_group w1_master_defattr_group = {
573 .attrs = w1_master_default_attrs,
574};
575
576int w1_create_master_attributes(struct w1_master *master)
577{
578 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
579}
580
581void w1_destroy_master_attributes(struct w1_master *master)
582{
583 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
584}
585
586static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
587{
588 struct w1_master *md = NULL;
589 struct w1_slave *sl = NULL;
590 char *event_owner, *name;
591 int err = 0;
592
593 if (dev->driver == &w1_master_driver) {
594 md = container_of(dev, struct w1_master, dev);
595 event_owner = "master";
596 name = md->name;
597 } else if (dev->driver == &w1_slave_driver) {
598 sl = container_of(dev, struct w1_slave, dev);
599 event_owner = "slave";
600 name = sl->name;
601 } else {
602 dev_dbg(dev, "Unknown event.\n");
603 return -EINVAL;
604 }
605
606 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
607 event_owner, name, dev_name(dev));
608
609 if (dev->driver != &w1_slave_driver || !sl)
610 goto end;
611
612 err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
613 if (err)
614 goto end;
615
616 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
617 (unsigned long long)sl->reg_num.id);
618end:
619 return err;
620}
621
622static int w1_family_notify(unsigned long action, struct w1_slave *sl)
623{
624 struct w1_family_ops *fops;
625 int err;
626
627 fops = sl->family->fops;
628
629 if (!fops)
630 return 0;
631
632 switch (action) {
633 case BUS_NOTIFY_ADD_DEVICE:
634 /* if the family driver needs to initialize something... */
635 if (fops->add_slave) {
636 err = fops->add_slave(sl);
637 if (err < 0) {
638 dev_err(&sl->dev,
639 "add_slave() call failed. err=%d\n",
640 err);
641 return err;
642 }
643 }
644 if (fops->groups) {
645 err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
646 if (err) {
647 dev_err(&sl->dev,
648 "sysfs group creation failed. err=%d\n",
649 err);
650 return err;
651 }
652 }
653 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info) {
654 struct device *hwmon
655 = hwmon_device_register_with_info(&sl->dev,
656 "w1_slave_temp", sl,
657 fops->chip_info,
658 NULL);
659 if (IS_ERR(hwmon)) {
660 dev_warn(&sl->dev,
661 "could not create hwmon device\n");
662 } else {
663 sl->hwmon = hwmon;
664 }
665 }
666 break;
667 case BUS_NOTIFY_DEL_DEVICE:
668 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info &&
669 sl->hwmon)
670 hwmon_device_unregister(sl->hwmon);
671 if (fops->remove_slave)
672 sl->family->fops->remove_slave(sl);
673 if (fops->groups)
674 sysfs_remove_groups(&sl->dev.kobj, fops->groups);
675 break;
676 }
677 return 0;
678}
679
680static int __w1_attach_slave_device(struct w1_slave *sl)
681{
682 int err;
683
684 sl->dev.parent = &sl->master->dev;
685 sl->dev.driver = &w1_slave_driver;
686 sl->dev.bus = &w1_bus_type;
687 sl->dev.release = &w1_slave_release;
688 sl->dev.groups = w1_slave_groups;
689
690 dev_set_name(&sl->dev, "%02x-%012llx",
691 (unsigned int) sl->reg_num.family,
692 (unsigned long long) sl->reg_num.id);
693 snprintf(&sl->name[0], sizeof(sl->name),
694 "%02x-%012llx",
695 (unsigned int) sl->reg_num.family,
696 (unsigned long long) sl->reg_num.id);
697
698 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
699 dev_name(&sl->dev), sl);
700
701 /* suppress for w1_family_notify before sending KOBJ_ADD */
702 dev_set_uevent_suppress(&sl->dev, true);
703
704 err = device_register(&sl->dev);
705 if (err < 0) {
706 dev_err(&sl->dev,
707 "Device registration [%s] failed. err=%d\n",
708 dev_name(&sl->dev), err);
709 put_device(&sl->dev);
710 return err;
711 }
712 w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl);
713
714 dev_set_uevent_suppress(&sl->dev, false);
715 kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
716
717 mutex_lock(&sl->master->list_mutex);
718 list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
719 mutex_unlock(&sl->master->list_mutex);
720
721 return 0;
722}
723
724int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
725{
726 struct w1_slave *sl;
727 struct w1_family *f;
728 int err;
729 struct w1_netlink_msg msg;
730
731 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
732 if (!sl) {
733 dev_err(&dev->dev,
734 "%s: failed to allocate new slave device.\n",
735 __func__);
736 return -ENOMEM;
737 }
738
739
740 sl->owner = THIS_MODULE;
741 sl->master = dev;
742 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
743
744 memset(&msg, 0, sizeof(msg));
745 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
746 atomic_set(&sl->refcnt, 1);
747 atomic_inc(&sl->master->refcnt);
748 dev->slave_count++;
749 dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",
750 rn->family, (unsigned long long)rn->id, rn->crc);
751
752 /* slave modules need to be loaded in a context with unlocked mutex */
753 mutex_unlock(&dev->mutex);
754 request_module("w1-family-0x%02x", rn->family);
755 mutex_lock(&dev->mutex);
756
757 spin_lock(&w1_flock);
758 f = w1_family_registered(rn->family);
759 if (!f) {
760 f= &w1_default_family;
761 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
762 rn->family, rn->family,
763 (unsigned long long)rn->id, rn->crc);
764 }
765 __w1_family_get(f);
766 spin_unlock(&w1_flock);
767
768 sl->family = f;
769
770 err = __w1_attach_slave_device(sl);
771 if (err < 0) {
772 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
773 sl->name);
774 dev->slave_count--;
775 w1_family_put(sl->family);
776 atomic_dec(&sl->master->refcnt);
777 kfree(sl);
778 return err;
779 }
780
781 sl->ttl = dev->slave_ttl;
782
783 memcpy(msg.id.id, rn, sizeof(msg.id));
784 msg.type = W1_SLAVE_ADD;
785 w1_netlink_send(dev, &msg);
786
787 return 0;
788}
789
790int w1_unref_slave(struct w1_slave *sl)
791{
792 struct w1_master *dev = sl->master;
793 int refcnt;
794 mutex_lock(&dev->list_mutex);
795 refcnt = atomic_sub_return(1, &sl->refcnt);
796 if (refcnt == 0) {
797 struct w1_netlink_msg msg;
798
799 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
800 sl->name, sl);
801
802 list_del(&sl->w1_slave_entry);
803
804 memset(&msg, 0, sizeof(msg));
805 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
806 msg.type = W1_SLAVE_REMOVE;
807 w1_netlink_send(sl->master, &msg);
808
809 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);
810 device_unregister(&sl->dev);
811 #ifdef DEBUG
812 memset(sl, 0, sizeof(*sl));
813 #endif
814 kfree(sl);
815 }
816 atomic_dec(&dev->refcnt);
817 mutex_unlock(&dev->list_mutex);
818 return refcnt;
819}
820
821int w1_slave_detach(struct w1_slave *sl)
822{
823 /* Only detach a slave once as it decreases the refcnt each time. */
824 int destroy_now;
825 mutex_lock(&sl->master->list_mutex);
826 destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
827 set_bit(W1_SLAVE_DETACH, &sl->flags);
828 mutex_unlock(&sl->master->list_mutex);
829
830 if (destroy_now)
831 destroy_now = !w1_unref_slave(sl);
832 return destroy_now ? 0 : -EBUSY;
833}
834
835struct w1_master *w1_search_master_id(u32 id)
836{
837 struct w1_master *dev;
838 int found = 0;
839
840 mutex_lock(&w1_mlock);
841 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
842 if (dev->id == id) {
843 found = 1;
844 atomic_inc(&dev->refcnt);
845 break;
846 }
847 }
848 mutex_unlock(&w1_mlock);
849
850 return (found)?dev:NULL;
851}
852
853struct w1_slave *w1_search_slave(struct w1_reg_num *id)
854{
855 struct w1_master *dev;
856 struct w1_slave *sl = NULL;
857 int found = 0;
858
859 mutex_lock(&w1_mlock);
860 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
861 mutex_lock(&dev->list_mutex);
862 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
863 if (sl->reg_num.family == id->family &&
864 sl->reg_num.id == id->id &&
865 sl->reg_num.crc == id->crc) {
866 found = 1;
867 atomic_inc(&dev->refcnt);
868 atomic_inc(&sl->refcnt);
869 break;
870 }
871 }
872 mutex_unlock(&dev->list_mutex);
873
874 if (found)
875 break;
876 }
877 mutex_unlock(&w1_mlock);
878
879 return (found)?sl:NULL;
880}
881
882void w1_reconnect_slaves(struct w1_family *f, int attach)
883{
884 struct w1_slave *sl, *sln;
885 struct w1_master *dev;
886
887 mutex_lock(&w1_mlock);
888 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
889 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
890 "for family %02x.\n", dev->name, f->fid);
891 mutex_lock(&dev->mutex);
892 mutex_lock(&dev->list_mutex);
893 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
894 /* If it is a new family, slaves with the default
895 * family driver and are that family will be
896 * connected. If the family is going away, devices
897 * matching that family are reconneced.
898 */
899 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
900 && sl->reg_num.family == f->fid) ||
901 (!attach && sl->family->fid == f->fid)) {
902 struct w1_reg_num rn;
903
904 mutex_unlock(&dev->list_mutex);
905 memcpy(&rn, &sl->reg_num, sizeof(rn));
906 /* If it was already in use let the automatic
907 * scan pick it up again later.
908 */
909 if (!w1_slave_detach(sl))
910 w1_attach_slave_device(dev, &rn);
911 mutex_lock(&dev->list_mutex);
912 }
913 }
914 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
915 "has been finished.\n", dev->name);
916 mutex_unlock(&dev->list_mutex);
917 mutex_unlock(&dev->mutex);
918 }
919 mutex_unlock(&w1_mlock);
920}
921
922void w1_slave_found(struct w1_master *dev, u64 rn)
923{
924 struct w1_slave *sl;
925 struct w1_reg_num *tmp;
926 u64 rn_le = cpu_to_le64(rn);
927
928 atomic_inc(&dev->refcnt);
929
930 tmp = (struct w1_reg_num *) &rn;
931
932 sl = w1_slave_search_device(dev, tmp);
933 if (sl) {
934 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
935 } else {
936 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
937 w1_attach_slave_device(dev, tmp);
938 }
939
940 atomic_dec(&dev->refcnt);
941}
942
943/**
944 * w1_search() - Performs a ROM Search & registers any devices found.
945 * @dev: The master device to search
946 * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH
947 * to return only devices in the alarmed state
948 * @cb: Function to call when a device is found
949 *
950 * The 1-wire search is a simple binary tree search.
951 * For each bit of the address, we read two bits and write one bit.
952 * The bit written will put to sleep all devies that don't match that bit.
953 * When the two reads differ, the direction choice is obvious.
954 * When both bits are 0, we must choose a path to take.
955 * When we can scan all 64 bits without having to choose a path, we are done.
956 *
957 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
958 *
959 */
960void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
961{
962 u64 last_rn, rn, tmp64;
963 int i, slave_count = 0;
964 int last_zero, last_device;
965 int search_bit, desc_bit;
966 u8 triplet_ret = 0;
967
968 search_bit = 0;
969 rn = dev->search_id;
970 last_rn = 0;
971 last_device = 0;
972 last_zero = -1;
973
974 desc_bit = 64;
975
976 while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
977 last_rn = rn;
978 rn = 0;
979
980 /*
981 * Reset bus and all 1-wire device state machines
982 * so they can respond to our requests.
983 *
984 * Return 0 - device(s) present, 1 - no devices present.
985 */
986 mutex_lock(&dev->bus_mutex);
987 if (w1_reset_bus(dev)) {
988 mutex_unlock(&dev->bus_mutex);
989 dev_dbg(&dev->dev, "No devices present on the wire.\n");
990 break;
991 }
992
993 /* Do fast search on single slave bus */
994 if (dev->max_slave_count == 1) {
995 int rv;
996 w1_write_8(dev, W1_READ_ROM);
997 rv = w1_read_block(dev, (u8 *)&rn, 8);
998 mutex_unlock(&dev->bus_mutex);
999
1000 if (rv == 8 && rn)
1001 cb(dev, rn);
1002
1003 break;
1004 }
1005
1006 /* Start the search */
1007 w1_write_8(dev, search_type);
1008 for (i = 0; i < 64; ++i) {
1009 /* Determine the direction/search bit */
1010 if (i == desc_bit)
1011 search_bit = 1; /* took the 0 path last time, so take the 1 path */
1012 else if (i > desc_bit)
1013 search_bit = 0; /* take the 0 path on the next branch */
1014 else
1015 search_bit = ((last_rn >> i) & 0x1);
1016
1017 /* Read two bits and write one bit */
1018 triplet_ret = w1_triplet(dev, search_bit);
1019
1020 /* quit if no device responded */
1021 if ( (triplet_ret & 0x03) == 0x03 )
1022 break;
1023
1024 /* If both directions were valid, and we took the 0 path... */
1025 if (triplet_ret == 0)
1026 last_zero = i;
1027
1028 /* extract the direction taken & update the device number */
1029 tmp64 = (triplet_ret >> 2);
1030 rn |= (tmp64 << i);
1031
1032 if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
1033 mutex_unlock(&dev->bus_mutex);
1034 dev_dbg(&dev->dev, "Abort w1_search\n");
1035 return;
1036 }
1037 }
1038 mutex_unlock(&dev->bus_mutex);
1039
1040 if ( (triplet_ret & 0x03) != 0x03 ) {
1041 if ((desc_bit == last_zero) || (last_zero < 0)) {
1042 last_device = 1;
1043 dev->search_id = 0;
1044 } else {
1045 dev->search_id = rn;
1046 }
1047 desc_bit = last_zero;
1048 cb(dev, rn);
1049 }
1050
1051 if (!last_device && slave_count == dev->max_slave_count &&
1052 !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
1053 /* Only max_slave_count will be scanned in a search,
1054 * but it will start where it left off next search
1055 * until all ids are identified and then it will start
1056 * over. A continued search will report the previous
1057 * last id as the first id (provided it is still on the
1058 * bus).
1059 */
1060 dev_info(&dev->dev, "%s: max_slave_count %d reached, "
1061 "will continue next search.\n", __func__,
1062 dev->max_slave_count);
1063 set_bit(W1_WARN_MAX_COUNT, &dev->flags);
1064 }
1065 }
1066}
1067
1068void w1_search_process_cb(struct w1_master *dev, u8 search_type,
1069 w1_slave_found_callback cb)
1070{
1071 struct w1_slave *sl, *sln;
1072
1073 mutex_lock(&dev->list_mutex);
1074 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
1075 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
1076 mutex_unlock(&dev->list_mutex);
1077
1078 w1_search_devices(dev, search_type, cb);
1079
1080 mutex_lock(&dev->list_mutex);
1081 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
1082 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
1083 mutex_unlock(&dev->list_mutex);
1084 w1_slave_detach(sl);
1085 mutex_lock(&dev->list_mutex);
1086 }
1087 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
1088 sl->ttl = dev->slave_ttl;
1089 }
1090 mutex_unlock(&dev->list_mutex);
1091
1092 if (dev->search_count > 0)
1093 dev->search_count--;
1094}
1095
1096static void w1_search_process(struct w1_master *dev, u8 search_type)
1097{
1098 w1_search_process_cb(dev, search_type, w1_slave_found);
1099}
1100
1101/**
1102 * w1_process_callbacks() - execute each dev->async_list callback entry
1103 * @dev: w1_master device
1104 *
1105 * The w1 master list_mutex must be held.
1106 *
1107 * Return: 1 if there were commands to executed 0 otherwise
1108 */
1109int w1_process_callbacks(struct w1_master *dev)
1110{
1111 int ret = 0;
1112 struct w1_async_cmd *async_cmd, *async_n;
1113
1114 /* The list can be added to in another thread, loop until it is empty */
1115 while (!list_empty(&dev->async_list)) {
1116 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
1117 async_entry) {
1118 /* drop the lock, if it is a search it can take a long
1119 * time */
1120 mutex_unlock(&dev->list_mutex);
1121 async_cmd->cb(dev, async_cmd);
1122 ret = 1;
1123 mutex_lock(&dev->list_mutex);
1124 }
1125 }
1126 return ret;
1127}
1128
1129int w1_process(void *data)
1130{
1131 struct w1_master *dev = (struct w1_master *) data;
1132 /* As long as w1_timeout is only set by a module parameter the sleep
1133 * time can be calculated in jiffies once.
1134 */
1135 const unsigned long jtime =
1136 usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);
1137 /* remainder if it woke up early */
1138 unsigned long jremain = 0;
1139
1140 for (;;) {
1141
1142 if (!jremain && dev->search_count) {
1143 mutex_lock(&dev->mutex);
1144 w1_search_process(dev, W1_SEARCH);
1145 mutex_unlock(&dev->mutex);
1146 }
1147
1148 mutex_lock(&dev->list_mutex);
1149 /* Note, w1_process_callback drops the lock while processing,
1150 * but locks it again before returning.
1151 */
1152 if (!w1_process_callbacks(dev) && jremain) {
1153 /* a wake up is either to stop the thread, process
1154 * callbacks, or search, it isn't process callbacks, so
1155 * schedule a search.
1156 */
1157 jremain = 1;
1158 }
1159
1160 __set_current_state(TASK_INTERRUPTIBLE);
1161
1162 /* hold list_mutex until after interruptible to prevent loosing
1163 * the wakeup signal when async_cmd is added.
1164 */
1165 mutex_unlock(&dev->list_mutex);
1166
1167 if (kthread_should_stop())
1168 break;
1169
1170 /* Only sleep when the search is active. */
1171 if (dev->search_count) {
1172 if (!jremain)
1173 jremain = jtime;
1174 jremain = schedule_timeout(jremain);
1175 }
1176 else
1177 schedule();
1178 }
1179
1180 atomic_dec(&dev->refcnt);
1181
1182 return 0;
1183}
1184
1185static int __init w1_init(void)
1186{
1187 int retval;
1188
1189 pr_info("Driver for 1-wire Dallas network protocol.\n");
1190
1191 w1_init_netlink();
1192
1193 retval = bus_register(&w1_bus_type);
1194 if (retval) {
1195 pr_err("Failed to register bus. err=%d.\n", retval);
1196 goto err_out_exit_init;
1197 }
1198
1199 retval = driver_register(&w1_master_driver);
1200 if (retval) {
1201 pr_err("Failed to register master driver. err=%d.\n",
1202 retval);
1203 goto err_out_bus_unregister;
1204 }
1205
1206 retval = driver_register(&w1_slave_driver);
1207 if (retval) {
1208 pr_err("Failed to register slave driver. err=%d.\n",
1209 retval);
1210 goto err_out_master_unregister;
1211 }
1212
1213 return 0;
1214
1215#if 0
1216/* For undoing the slave register if there was a step after it. */
1217err_out_slave_unregister:
1218 driver_unregister(&w1_slave_driver);
1219#endif
1220
1221err_out_master_unregister:
1222 driver_unregister(&w1_master_driver);
1223
1224err_out_bus_unregister:
1225 bus_unregister(&w1_bus_type);
1226
1227err_out_exit_init:
1228 return retval;
1229}
1230
1231static void __exit w1_fini(void)
1232{
1233 struct w1_master *dev;
1234
1235 /* Set netlink removal messages and some cleanup */
1236 list_for_each_entry(dev, &w1_masters, w1_master_entry)
1237 __w1_remove_master_device(dev);
1238
1239 w1_fini_netlink();
1240
1241 driver_unregister(&w1_slave_driver);
1242 driver_unregister(&w1_master_driver);
1243 bus_unregister(&w1_bus_type);
1244}
1245
1246module_init(w1_init);
1247module_exit(w1_fini);
1248
1249MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
1250MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
1251MODULE_LICENSE("GPL");