Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/pci-2.6
[linux-2.6] / drivers / w1 / w1.c
1 /*
2  *      w1.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
5  *
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21
22 #include <linux/delay.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/list.h>
27 #include <linux/interrupt.h>
28 #include <linux/spinlock.h>
29 #include <linux/timer.h>
30 #include <linux/device.h>
31 #include <linux/slab.h>
32 #include <linux/sched.h>
33
34 #include <asm/atomic.h>
35
36 #include "w1.h"
37 #include "w1_io.h"
38 #include "w1_log.h"
39 #include "w1_int.h"
40 #include "w1_family.h"
41 #include "w1_netlink.h"
42
43 MODULE_LICENSE("GPL");
44 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
45 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
46
47 static int w1_timeout = 10;
48 static int w1_control_timeout = 1;
49 int w1_max_slave_count = 10;
50 int w1_max_slave_ttl = 10;
51
52 module_param_named(timeout, w1_timeout, int, 0);
53 module_param_named(control_timeout, w1_control_timeout, int, 0);
54 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
55 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
56
57 DEFINE_SPINLOCK(w1_mlock);
58 LIST_HEAD(w1_masters);
59
60 static pid_t control_thread;
61 static int control_needs_exit;
62 static DECLARE_COMPLETION(w1_control_complete);
63
64 static int w1_master_match(struct device *dev, struct device_driver *drv)
65 {
66         return 1;
67 }
68
69 static int w1_master_probe(struct device *dev)
70 {
71         return -ENODEV;
72 }
73
74 static void w1_master_release(struct device *dev)
75 {
76         struct w1_master *md = dev_to_w1_master(dev);
77
78         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
79
80         dev_fini_netlink(md);
81         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
82         kfree(md);
83 }
84
85 static void w1_slave_release(struct device *dev)
86 {
87         struct w1_slave *sl = dev_to_w1_slave(dev);
88
89         dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
90
91         while (atomic_read(&sl->refcnt)) {
92                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
93                                 sl->name, atomic_read(&sl->refcnt));
94                 if (msleep_interruptible(1000))
95                         flush_signals(current);
96         }
97
98         w1_family_put(sl->family);
99         sl->master->slave_count--;
100
101         complete(&sl->released);
102 }
103
104 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
105 {
106         struct w1_slave *sl = dev_to_w1_slave(dev);
107
108         return sprintf(buf, "%s\n", sl->name);
109 }
110
111 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
112 {
113         struct w1_slave *sl = kobj_to_w1_slave(kobj);
114
115         atomic_inc(&sl->refcnt);
116         if (off > 8) {
117                 count = 0;
118         } else {
119                 if (off + count > 8)
120                         count = 8 - off;
121
122                 memcpy(buf, (u8 *)&sl->reg_num, count);
123         }
124         atomic_dec(&sl->refcnt);
125
126         return count;
127 }
128
129 static struct device_attribute w1_slave_attr_name =
130         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
131
132 static struct bin_attribute w1_slave_attr_bin_id = {
133       .attr = {
134               .name = "id",
135               .mode = S_IRUGO,
136               .owner = THIS_MODULE,
137       },
138       .size = 8,
139       .read = w1_slave_read_id,
140 };
141
142 /* Default family */
143 static struct w1_family w1_default_family;
144
145 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
146
147 static struct bus_type w1_bus_type = {
148         .name = "w1",
149         .match = w1_master_match,
150         .uevent = w1_uevent,
151 };
152
153 struct device_driver w1_master_driver = {
154         .name = "w1_master_driver",
155         .bus = &w1_bus_type,
156         .probe = w1_master_probe,
157 };
158
159 struct device w1_master_device = {
160         .parent = NULL,
161         .bus = &w1_bus_type,
162         .bus_id = "w1 bus master",
163         .driver = &w1_master_driver,
164         .release = &w1_master_release
165 };
166
167 struct device_driver w1_slave_driver = {
168         .name = "w1_slave_driver",
169         .bus = &w1_bus_type,
170 };
171
172 struct device w1_slave_device = {
173         .parent = NULL,
174         .bus = &w1_bus_type,
175         .bus_id = "w1 bus slave",
176         .driver = &w1_slave_driver,
177         .release = &w1_slave_release
178 };
179
180 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
181 {
182         struct w1_master *md = dev_to_w1_master(dev);
183         ssize_t count;
184
185         if (down_interruptible (&md->mutex))
186                 return -EBUSY;
187
188         count = sprintf(buf, "%s\n", md->name);
189
190         up(&md->mutex);
191
192         return count;
193 }
194
195 static ssize_t w1_master_attribute_store_search(struct device * dev,
196                                                 struct device_attribute *attr,
197                                                 const char * buf, size_t count)
198 {
199         struct w1_master *md = dev_to_w1_master(dev);
200
201         if (down_interruptible (&md->mutex))
202                 return -EBUSY;
203
204         md->search_count = simple_strtol(buf, NULL, 0);
205
206         up(&md->mutex);
207
208         return count;
209 }
210
211 static ssize_t w1_master_attribute_show_search(struct device *dev,
212                                                struct device_attribute *attr,
213                                                char *buf)
214 {
215         struct w1_master *md = dev_to_w1_master(dev);
216         ssize_t count;
217
218         if (down_interruptible (&md->mutex))
219                 return -EBUSY;
220
221         count = sprintf(buf, "%d\n", md->search_count);
222
223         up(&md->mutex);
224
225         return count;
226 }
227
228 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
229 {
230         struct w1_master *md = dev_to_w1_master(dev);
231         ssize_t count;
232
233         if (down_interruptible(&md->mutex))
234                 return -EBUSY;
235
236         count = sprintf(buf, "0x%p\n", md->bus_master);
237
238         up(&md->mutex);
239         return count;
240 }
241
242 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
243 {
244         ssize_t count;
245         count = sprintf(buf, "%d\n", w1_timeout);
246         return count;
247 }
248
249 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
250 {
251         struct w1_master *md = dev_to_w1_master(dev);
252         ssize_t count;
253
254         if (down_interruptible(&md->mutex))
255                 return -EBUSY;
256
257         count = sprintf(buf, "%d\n", md->max_slave_count);
258
259         up(&md->mutex);
260         return count;
261 }
262
263 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
264 {
265         struct w1_master *md = dev_to_w1_master(dev);
266         ssize_t count;
267
268         if (down_interruptible(&md->mutex))
269                 return -EBUSY;
270
271         count = sprintf(buf, "%lu\n", md->attempts);
272
273         up(&md->mutex);
274         return count;
275 }
276
277 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
278 {
279         struct w1_master *md = dev_to_w1_master(dev);
280         ssize_t count;
281
282         if (down_interruptible(&md->mutex))
283                 return -EBUSY;
284
285         count = sprintf(buf, "%d\n", md->slave_count);
286
287         up(&md->mutex);
288         return count;
289 }
290
291 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
292 {
293         struct w1_master *md = dev_to_w1_master(dev);
294         int c = PAGE_SIZE;
295
296         if (down_interruptible(&md->mutex))
297                 return -EBUSY;
298
299         if (md->slave_count == 0)
300                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
301         else {
302                 struct list_head *ent, *n;
303                 struct w1_slave *sl;
304
305                 list_for_each_safe(ent, n, &md->slist) {
306                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
307
308                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
309                 }
310         }
311
312         up(&md->mutex);
313
314         return PAGE_SIZE - c;
315 }
316
317 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
318         struct device_attribute w1_master_attribute_##_name =   \
319                 __ATTR(w1_master_##_name, _mode,                \
320                        w1_master_attribute_show_##_name, NULL)
321
322 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
323         struct device_attribute w1_master_attribute_##_name =   \
324                 __ATTR(w1_master_##_name, _mode,                \
325                        w1_master_attribute_show_##_name,        \
326                        w1_master_attribute_store_##_name)
327
328 static W1_MASTER_ATTR_RO(name, S_IRUGO);
329 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
330 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
331 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
332 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
333 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
334 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
335 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
336
337 static struct attribute *w1_master_default_attrs[] = {
338         &w1_master_attribute_name.attr,
339         &w1_master_attribute_slaves.attr,
340         &w1_master_attribute_slave_count.attr,
341         &w1_master_attribute_max_slave_count.attr,
342         &w1_master_attribute_attempts.attr,
343         &w1_master_attribute_timeout.attr,
344         &w1_master_attribute_pointer.attr,
345         &w1_master_attribute_search.attr,
346         NULL
347 };
348
349 static struct attribute_group w1_master_defattr_group = {
350         .attrs = w1_master_default_attrs,
351 };
352
353 int w1_create_master_attributes(struct w1_master *master)
354 {
355         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
356 }
357
358 void w1_destroy_master_attributes(struct w1_master *master)
359 {
360         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
361 }
362
363 #ifdef CONFIG_HOTPLUG
364 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
365 {
366         struct w1_master *md = NULL;
367         struct w1_slave *sl = NULL;
368         char *event_owner, *name;
369         int err, cur_index=0, cur_len=0;
370
371         if (dev->driver == &w1_master_driver) {
372                 md = container_of(dev, struct w1_master, dev);
373                 event_owner = "master";
374                 name = md->name;
375         } else if (dev->driver == &w1_slave_driver) {
376                 sl = container_of(dev, struct w1_slave, dev);
377                 event_owner = "slave";
378                 name = sl->name;
379         } else {
380                 dev_dbg(dev, "Unknown event.\n");
381                 return -EINVAL;
382         }
383
384         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
385
386         if (dev->driver != &w1_slave_driver || !sl)
387                 return 0;
388
389         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
390         if (err)
391                 return err;
392
393         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
394         if (err)
395                 return err;
396
397         return 0;
398 };
399 #else
400 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
401 {
402         return 0;
403 }
404 #endif
405
406 static int __w1_attach_slave_device(struct w1_slave *sl)
407 {
408         int err;
409
410         sl->dev.parent = &sl->master->dev;
411         sl->dev.driver = &w1_slave_driver;
412         sl->dev.bus = &w1_bus_type;
413         sl->dev.release = &w1_slave_release;
414
415         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
416                  "%02x-%012llx",
417                  (unsigned int) sl->reg_num.family,
418                  (unsigned long long) sl->reg_num.id);
419         snprintf(&sl->name[0], sizeof(sl->name),
420                  "%02x-%012llx",
421                  (unsigned int) sl->reg_num.family,
422                  (unsigned long long) sl->reg_num.id);
423
424         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
425
426         err = device_register(&sl->dev);
427         if (err < 0) {
428                 dev_err(&sl->dev,
429                         "Device registration [%s] failed. err=%d\n",
430                         sl->dev.bus_id, err);
431                 return err;
432         }
433
434         /* Create "name" entry */
435         err = device_create_file(&sl->dev, &w1_slave_attr_name);
436         if (err < 0) {
437                 dev_err(&sl->dev,
438                         "sysfs file creation for [%s] failed. err=%d\n",
439                         sl->dev.bus_id, err);
440                 goto out_unreg;
441         }
442
443         /* Create "id" entry */
444         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
445         if (err < 0) {
446                 dev_err(&sl->dev,
447                         "sysfs file creation for [%s] failed. err=%d\n",
448                         sl->dev.bus_id, err);
449                 goto out_rem1;
450         }
451
452         /* if the family driver needs to initialize something... */
453         if (sl->family->fops && sl->family->fops->add_slave &&
454             ((err = sl->family->fops->add_slave(sl)) < 0)) {
455                 dev_err(&sl->dev,
456                         "sysfs file creation for [%s] failed. err=%d\n",
457                         sl->dev.bus_id, err);
458                 goto out_rem2;
459         }
460
461         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
462
463         return 0;
464
465 out_rem2:
466         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
467 out_rem1:
468         device_remove_file(&sl->dev, &w1_slave_attr_name);
469 out_unreg:
470         device_unregister(&sl->dev);
471         return err;
472 }
473
474 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
475 {
476         struct w1_slave *sl;
477         struct w1_family *f;
478         int err;
479         struct w1_netlink_msg msg;
480
481         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
482         if (!sl) {
483                 dev_err(&dev->dev,
484                          "%s: failed to allocate new slave device.\n",
485                          __func__);
486                 return -ENOMEM;
487         }
488
489         memset(sl, 0, sizeof(*sl));
490
491         sl->owner = THIS_MODULE;
492         sl->master = dev;
493         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
494
495         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
496         atomic_set(&sl->refcnt, 0);
497         init_completion(&sl->released);
498
499         spin_lock(&w1_flock);
500         f = w1_family_registered(rn->family);
501         if (!f) {
502                 f= &w1_default_family;
503                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
504                           rn->family, rn->family,
505                           (unsigned long long)rn->id, rn->crc);
506         }
507         __w1_family_get(f);
508         spin_unlock(&w1_flock);
509
510         sl->family = f;
511
512
513         err = __w1_attach_slave_device(sl);
514         if (err < 0) {
515                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
516                          sl->name);
517                 w1_family_put(sl->family);
518                 kfree(sl);
519                 return err;
520         }
521
522         sl->ttl = dev->slave_ttl;
523         dev->slave_count++;
524
525         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
526         msg.type = W1_SLAVE_ADD;
527         w1_netlink_send(dev, &msg);
528
529         return 0;
530 }
531
532 static void w1_slave_detach(struct w1_slave *sl)
533 {
534         struct w1_netlink_msg msg;
535
536         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
537
538         list_del(&sl->w1_slave_entry);
539
540         if (sl->family->fops && sl->family->fops->remove_slave)
541                 sl->family->fops->remove_slave(sl);
542
543         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
544         msg.type = W1_SLAVE_REMOVE;
545         w1_netlink_send(sl->master, &msg);
546
547         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
548         device_remove_file(&sl->dev, &w1_slave_attr_name);
549         device_unregister(&sl->dev);
550
551         wait_for_completion(&sl->released);
552         kfree(sl);
553 }
554
555 static struct w1_master *w1_search_master(unsigned long data)
556 {
557         struct w1_master *dev;
558         int found = 0;
559
560         spin_lock_bh(&w1_mlock);
561         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
562                 if (dev->bus_master->data == data) {
563                         found = 1;
564                         atomic_inc(&dev->refcnt);
565                         break;
566                 }
567         }
568         spin_unlock_bh(&w1_mlock);
569
570         return (found)?dev:NULL;
571 }
572
573 void w1_reconnect_slaves(struct w1_family *f)
574 {
575         struct w1_master *dev;
576
577         spin_lock_bh(&w1_mlock);
578         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
579                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
580                                 dev->name, f->fid);
581                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
582         }
583         spin_unlock_bh(&w1_mlock);
584 }
585
586 static void w1_slave_found(unsigned long data, u64 rn)
587 {
588         int slave_count;
589         struct w1_slave *sl;
590         struct list_head *ent;
591         struct w1_reg_num *tmp;
592         int family_found = 0;
593         struct w1_master *dev;
594         u64 rn_le = cpu_to_le64(rn);
595
596         dev = w1_search_master(data);
597         if (!dev) {
598                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
599                                 data);
600                 return;
601         }
602
603         tmp = (struct w1_reg_num *) &rn;
604
605         slave_count = 0;
606         list_for_each(ent, &dev->slist) {
607
608                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
609
610                 if (sl->reg_num.family == tmp->family &&
611                     sl->reg_num.id == tmp->id &&
612                     sl->reg_num.crc == tmp->crc) {
613                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
614                         break;
615                 } else if (sl->reg_num.family == tmp->family) {
616                         family_found = 1;
617                         break;
618                 }
619
620                 slave_count++;
621         }
622
623         if (slave_count == dev->slave_count &&
624                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
625                 w1_attach_slave_device(dev, tmp);
626         }
627
628         atomic_dec(&dev->refcnt);
629 }
630
631 /**
632  * Performs a ROM Search & registers any devices found.
633  * The 1-wire search is a simple binary tree search.
634  * For each bit of the address, we read two bits and write one bit.
635  * The bit written will put to sleep all devies that don't match that bit.
636  * When the two reads differ, the direction choice is obvious.
637  * When both bits are 0, we must choose a path to take.
638  * When we can scan all 64 bits without having to choose a path, we are done.
639  *
640  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
641  *
642  * @dev        The master device to search
643  * @cb         Function to call when a device is found
644  */
645 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
646 {
647         u64 last_rn, rn, tmp64;
648         int i, slave_count = 0;
649         int last_zero, last_device;
650         int search_bit, desc_bit;
651         u8  triplet_ret = 0;
652
653         search_bit = 0;
654         rn = last_rn = 0;
655         last_device = 0;
656         last_zero = -1;
657
658         desc_bit = 64;
659
660         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
661                 last_rn = rn;
662                 rn = 0;
663
664                 /*
665                  * Reset bus and all 1-wire device state machines
666                  * so they can respond to our requests.
667                  *
668                  * Return 0 - device(s) present, 1 - no devices present.
669                  */
670                 if (w1_reset_bus(dev)) {
671                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
672                         break;
673                 }
674
675                 /* Start the search */
676                 w1_write_8(dev, W1_SEARCH);
677                 for (i = 0; i < 64; ++i) {
678                         /* Determine the direction/search bit */
679                         if (i == desc_bit)
680                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
681                         else if (i > desc_bit)
682                                 search_bit = 0;   /* take the 0 path on the next branch */
683                         else
684                                 search_bit = ((last_rn >> i) & 0x1);
685
686                         /** Read two bits and write one bit */
687                         triplet_ret = w1_triplet(dev, search_bit);
688
689                         /* quit if no device responded */
690                         if ( (triplet_ret & 0x03) == 0x03 )
691                                 break;
692
693                         /* If both directions were valid, and we took the 0 path... */
694                         if (triplet_ret == 0)
695                                 last_zero = i;
696
697                         /* extract the direction taken & update the device number */
698                         tmp64 = (triplet_ret >> 2);
699                         rn |= (tmp64 << i);
700                 }
701
702                 if ( (triplet_ret & 0x03) != 0x03 ) {
703                         if ( (desc_bit == last_zero) || (last_zero < 0))
704                                 last_device = 1;
705                         desc_bit = last_zero;
706                         cb(dev->bus_master->data, rn);
707                 }
708         }
709 }
710
711 static int w1_control(void *data)
712 {
713         struct w1_slave *sl, *sln;
714         struct w1_master *dev, *n;
715         int err, have_to_wait = 0;
716
717         daemonize("w1_control");
718         allow_signal(SIGTERM);
719
720         while (!control_needs_exit || have_to_wait) {
721                 have_to_wait = 0;
722
723                 try_to_freeze();
724                 msleep_interruptible(w1_control_timeout * 1000);
725
726                 if (signal_pending(current))
727                         flush_signals(current);
728
729                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
730                         if (!control_needs_exit && !dev->flags)
731                                 continue;
732                         /*
733                          * Little race: we can create thread but not set the flag.
734                          * Get a chance for external process to set flag up.
735                          */
736                         if (!dev->initialized) {
737                                 have_to_wait = 1;
738                                 continue;
739                         }
740
741                         if (control_needs_exit) {
742                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
743
744                                 err = kill_proc(dev->kpid, SIGTERM, 1);
745                                 if (err)
746                                         dev_err(&dev->dev,
747                                                  "Failed to send signal to w1 kernel thread %d.\n",
748                                                  dev->kpid);
749                         }
750
751                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
752                                 wait_for_completion(&dev->dev_exited);
753                                 spin_lock_bh(&w1_mlock);
754                                 list_del(&dev->w1_master_entry);
755                                 spin_unlock_bh(&w1_mlock);
756
757                                 down(&dev->mutex);
758                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
759                                         w1_slave_detach(sl);
760                                 }
761                                 w1_destroy_master_attributes(dev);
762                                 up(&dev->mutex);
763                                 atomic_dec(&dev->refcnt);
764                                 continue;
765                         }
766
767                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
768                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
769                                 down(&dev->mutex);
770                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
771                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
772                                                 struct w1_reg_num rn;
773
774                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
775                                                 w1_slave_detach(sl);
776
777                                                 w1_attach_slave_device(dev, &rn);
778                                         }
779                                 }
780                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
781                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
782                                 up(&dev->mutex);
783                         }
784                 }
785         }
786
787         complete_and_exit(&w1_control_complete, 0);
788 }
789
790 int w1_process(void *data)
791 {
792         struct w1_master *dev = (struct w1_master *) data;
793         struct w1_slave *sl, *sln;
794
795         daemonize("%s", dev->name);
796         allow_signal(SIGTERM);
797
798         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
799                 try_to_freeze();
800                 msleep_interruptible(w1_timeout * 1000);
801
802                 if (signal_pending(current))
803                         flush_signals(current);
804
805                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
806                         break;
807
808                 if (!dev->initialized)
809                         continue;
810
811                 if (dev->search_count == 0)
812                         continue;
813
814                 if (down_interruptible(&dev->mutex))
815                         continue;
816
817                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
818                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
819
820                 w1_search_devices(dev, w1_slave_found);
821
822                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
823                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
824                                 w1_slave_detach(sl);
825
826                                 dev->slave_count--;
827                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
828                                 sl->ttl = dev->slave_ttl;
829                 }
830
831                 if (dev->search_count > 0)
832                         dev->search_count--;
833
834                 up(&dev->mutex);
835         }
836
837         atomic_dec(&dev->refcnt);
838         complete_and_exit(&dev->dev_exited, 0);
839
840         return 0;
841 }
842
843 static int w1_init(void)
844 {
845         int retval;
846
847         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
848
849         retval = bus_register(&w1_bus_type);
850         if (retval) {
851                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
852                 goto err_out_exit_init;
853         }
854
855         retval = driver_register(&w1_master_driver);
856         if (retval) {
857                 printk(KERN_ERR
858                         "Failed to register master driver. err=%d.\n",
859                         retval);
860                 goto err_out_bus_unregister;
861         }
862
863         retval = driver_register(&w1_slave_driver);
864         if (retval) {
865                 printk(KERN_ERR
866                         "Failed to register master driver. err=%d.\n",
867                         retval);
868                 goto err_out_master_unregister;
869         }
870
871         control_thread = kernel_thread(&w1_control, NULL, 0);
872         if (control_thread < 0) {
873                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
874                         control_thread);
875                 retval = control_thread;
876                 goto err_out_slave_unregister;
877         }
878
879         return 0;
880
881 err_out_slave_unregister:
882         driver_unregister(&w1_slave_driver);
883
884 err_out_master_unregister:
885         driver_unregister(&w1_master_driver);
886
887 err_out_bus_unregister:
888         bus_unregister(&w1_bus_type);
889
890 err_out_exit_init:
891         return retval;
892 }
893
894 static void w1_fini(void)
895 {
896         struct w1_master *dev;
897
898         list_for_each_entry(dev, &w1_masters, w1_master_entry)
899                 __w1_remove_master_device(dev);
900
901         control_needs_exit = 1;
902         wait_for_completion(&w1_control_complete);
903
904         driver_unregister(&w1_slave_driver);
905         driver_unregister(&w1_master_driver);
906         bus_unregister(&w1_bus_type);
907 }
908
909 module_init(w1_init);
910 module_exit(w1_fini);