Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/pci-2.6
[linux-2.6.git] / 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 #include <linux/kthread.h>
34
35 #include <asm/atomic.h>
36
37 #include "w1.h"
38 #include "w1_io.h"
39 #include "w1_log.h"
40 #include "w1_int.h"
41 #include "w1_family.h"
42 #include "w1_netlink.h"
43
44 MODULE_LICENSE("GPL");
45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
47
48 static int w1_timeout = 10;
49 static int w1_control_timeout = 1;
50 int w1_max_slave_count = 10;
51 int w1_max_slave_ttl = 10;
52
53 module_param_named(timeout, w1_timeout, int, 0);
54 module_param_named(control_timeout, w1_control_timeout, int, 0);
55 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
56 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
57
58 DEFINE_SPINLOCK(w1_mlock);
59 LIST_HEAD(w1_masters);
60
61 static struct task_struct *w1_control_thread;
62
63 static int w1_master_match(struct device *dev, struct device_driver *drv)
64 {
65         return 1;
66 }
67
68 static int w1_master_probe(struct device *dev)
69 {
70         return -ENODEV;
71 }
72
73 static void w1_master_release(struct device *dev)
74 {
75         struct w1_master *md = dev_to_w1_master(dev);
76
77         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
78
79         dev_fini_netlink(md);
80         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
81         kfree(md);
82 }
83
84 static void w1_slave_release(struct device *dev)
85 {
86         struct w1_slave *sl = dev_to_w1_slave(dev);
87
88         dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
89
90         while (atomic_read(&sl->refcnt)) {
91                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
92                                 sl->name, atomic_read(&sl->refcnt));
93                 if (msleep_interruptible(1000))
94                         flush_signals(current);
95         }
96
97         w1_family_put(sl->family);
98         sl->master->slave_count--;
99
100         complete(&sl->released);
101 }
102
103 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
104 {
105         struct w1_slave *sl = dev_to_w1_slave(dev);
106
107         return sprintf(buf, "%s\n", sl->name);
108 }
109
110 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
111 {
112         struct w1_slave *sl = kobj_to_w1_slave(kobj);
113
114         atomic_inc(&sl->refcnt);
115         if (off > 8) {
116                 count = 0;
117         } else {
118                 if (off + count > 8)
119                         count = 8 - off;
120
121                 memcpy(buf, (u8 *)&sl->reg_num, count);
122         }
123         atomic_dec(&sl->refcnt);
124
125         return count;
126 }
127
128 static struct device_attribute w1_slave_attr_name =
129         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
130
131 static struct bin_attribute w1_slave_attr_bin_id = {
132       .attr = {
133               .name = "id",
134               .mode = S_IRUGO,
135               .owner = THIS_MODULE,
136       },
137       .size = 8,
138       .read = w1_slave_read_id,
139 };
140
141 /* Default family */
142 static struct w1_family w1_default_family;
143
144 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
145
146 static struct bus_type w1_bus_type = {
147         .name = "w1",
148         .match = w1_master_match,
149         .uevent = w1_uevent,
150 };
151
152 struct device_driver w1_master_driver = {
153         .name = "w1_master_driver",
154         .bus = &w1_bus_type,
155         .probe = w1_master_probe,
156 };
157
158 struct device w1_master_device = {
159         .parent = NULL,
160         .bus = &w1_bus_type,
161         .bus_id = "w1 bus master",
162         .driver = &w1_master_driver,
163         .release = &w1_master_release
164 };
165
166 static struct device_driver w1_slave_driver = {
167         .name = "w1_slave_driver",
168         .bus = &w1_bus_type,
169 };
170
171 #if 0
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 #endif  /*  0  */
180
181 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
182 {
183         struct w1_master *md = dev_to_w1_master(dev);
184         ssize_t count;
185
186         if (down_interruptible (&md->mutex))
187                 return -EBUSY;
188
189         count = sprintf(buf, "%s\n", md->name);
190
191         up(&md->mutex);
192
193         return count;
194 }
195
196 static ssize_t w1_master_attribute_store_search(struct device * dev,
197                                                 struct device_attribute *attr,
198                                                 const char * buf, size_t count)
199 {
200         struct w1_master *md = dev_to_w1_master(dev);
201
202         if (down_interruptible (&md->mutex))
203                 return -EBUSY;
204
205         md->search_count = simple_strtol(buf, NULL, 0);
206
207         up(&md->mutex);
208
209         return count;
210 }
211
212 static ssize_t w1_master_attribute_show_search(struct device *dev,
213                                                struct device_attribute *attr,
214                                                char *buf)
215 {
216         struct w1_master *md = dev_to_w1_master(dev);
217         ssize_t count;
218
219         if (down_interruptible (&md->mutex))
220                 return -EBUSY;
221
222         count = sprintf(buf, "%d\n", md->search_count);
223
224         up(&md->mutex);
225
226         return count;
227 }
228
229 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
230 {
231         struct w1_master *md = dev_to_w1_master(dev);
232         ssize_t count;
233
234         if (down_interruptible(&md->mutex))
235                 return -EBUSY;
236
237         count = sprintf(buf, "0x%p\n", md->bus_master);
238
239         up(&md->mutex);
240         return count;
241 }
242
243 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
244 {
245         ssize_t count;
246         count = sprintf(buf, "%d\n", w1_timeout);
247         return count;
248 }
249
250 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
251 {
252         struct w1_master *md = dev_to_w1_master(dev);
253         ssize_t count;
254
255         if (down_interruptible(&md->mutex))
256                 return -EBUSY;
257
258         count = sprintf(buf, "%d\n", md->max_slave_count);
259
260         up(&md->mutex);
261         return count;
262 }
263
264 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
265 {
266         struct w1_master *md = dev_to_w1_master(dev);
267         ssize_t count;
268
269         if (down_interruptible(&md->mutex))
270                 return -EBUSY;
271
272         count = sprintf(buf, "%lu\n", md->attempts);
273
274         up(&md->mutex);
275         return count;
276 }
277
278 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
279 {
280         struct w1_master *md = dev_to_w1_master(dev);
281         ssize_t count;
282
283         if (down_interruptible(&md->mutex))
284                 return -EBUSY;
285
286         count = sprintf(buf, "%d\n", md->slave_count);
287
288         up(&md->mutex);
289         return count;
290 }
291
292 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
293 {
294         struct w1_master *md = dev_to_w1_master(dev);
295         int c = PAGE_SIZE;
296
297         if (down_interruptible(&md->mutex))
298                 return -EBUSY;
299
300         if (md->slave_count == 0)
301                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
302         else {
303                 struct list_head *ent, *n;
304                 struct w1_slave *sl;
305
306                 list_for_each_safe(ent, n, &md->slist) {
307                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
308
309                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
310                 }
311         }
312
313         up(&md->mutex);
314
315         return PAGE_SIZE - c;
316 }
317
318 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
319         struct device_attribute w1_master_attribute_##_name =   \
320                 __ATTR(w1_master_##_name, _mode,                \
321                        w1_master_attribute_show_##_name, NULL)
322
323 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
324         struct device_attribute w1_master_attribute_##_name =   \
325                 __ATTR(w1_master_##_name, _mode,                \
326                        w1_master_attribute_show_##_name,        \
327                        w1_master_attribute_store_##_name)
328
329 static W1_MASTER_ATTR_RO(name, S_IRUGO);
330 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
331 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
332 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
333 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
334 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
335 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
336 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
337
338 static struct attribute *w1_master_default_attrs[] = {
339         &w1_master_attribute_name.attr,
340         &w1_master_attribute_slaves.attr,
341         &w1_master_attribute_slave_count.attr,
342         &w1_master_attribute_max_slave_count.attr,
343         &w1_master_attribute_attempts.attr,
344         &w1_master_attribute_timeout.attr,
345         &w1_master_attribute_pointer.attr,
346         &w1_master_attribute_search.attr,
347         NULL
348 };
349
350 static struct attribute_group w1_master_defattr_group = {
351         .attrs = w1_master_default_attrs,
352 };
353
354 int w1_create_master_attributes(struct w1_master *master)
355 {
356         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
357 }
358
359 static void w1_destroy_master_attributes(struct w1_master *master)
360 {
361         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
362 }
363
364 #ifdef CONFIG_HOTPLUG
365 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
366 {
367         struct w1_master *md = NULL;
368         struct w1_slave *sl = NULL;
369         char *event_owner, *name;
370         int err, cur_index=0, cur_len=0;
371
372         if (dev->driver == &w1_master_driver) {
373                 md = container_of(dev, struct w1_master, dev);
374                 event_owner = "master";
375                 name = md->name;
376         } else if (dev->driver == &w1_slave_driver) {
377                 sl = container_of(dev, struct w1_slave, dev);
378                 event_owner = "slave";
379                 name = sl->name;
380         } else {
381                 dev_dbg(dev, "Unknown event.\n");
382                 return -EINVAL;
383         }
384
385         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
386
387         if (dev->driver != &w1_slave_driver || !sl)
388                 return 0;
389
390         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
391                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
392         if (err)
393                 return err;
394
395         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
396                         &cur_len, "W1_SLAVE_ID=%024LX",
397                         (unsigned long long)sl->reg_num.id);
398         if (err)
399                 return err;
400
401         return 0;
402 };
403 #else
404 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
405 {
406         return 0;
407 }
408 #endif
409
410 static int __w1_attach_slave_device(struct w1_slave *sl)
411 {
412         int err;
413
414         sl->dev.parent = &sl->master->dev;
415         sl->dev.driver = &w1_slave_driver;
416         sl->dev.bus = &w1_bus_type;
417         sl->dev.release = &w1_slave_release;
418
419         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
420                  "%02x-%012llx",
421                  (unsigned int) sl->reg_num.family,
422                  (unsigned long long) sl->reg_num.id);
423         snprintf(&sl->name[0], sizeof(sl->name),
424                  "%02x-%012llx",
425                  (unsigned int) sl->reg_num.family,
426                  (unsigned long long) sl->reg_num.id);
427
428         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
429
430         err = device_register(&sl->dev);
431         if (err < 0) {
432                 dev_err(&sl->dev,
433                         "Device registration [%s] failed. err=%d\n",
434                         sl->dev.bus_id, err);
435                 return err;
436         }
437
438         /* Create "name" entry */
439         err = device_create_file(&sl->dev, &w1_slave_attr_name);
440         if (err < 0) {
441                 dev_err(&sl->dev,
442                         "sysfs file creation for [%s] failed. err=%d\n",
443                         sl->dev.bus_id, err);
444                 goto out_unreg;
445         }
446
447         /* Create "id" entry */
448         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
449         if (err < 0) {
450                 dev_err(&sl->dev,
451                         "sysfs file creation for [%s] failed. err=%d\n",
452                         sl->dev.bus_id, err);
453                 goto out_rem1;
454         }
455
456         /* if the family driver needs to initialize something... */
457         if (sl->family->fops && sl->family->fops->add_slave &&
458             ((err = sl->family->fops->add_slave(sl)) < 0)) {
459                 dev_err(&sl->dev,
460                         "sysfs file creation for [%s] failed. err=%d\n",
461                         sl->dev.bus_id, err);
462                 goto out_rem2;
463         }
464
465         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
466
467         return 0;
468
469 out_rem2:
470         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
471 out_rem1:
472         device_remove_file(&sl->dev, &w1_slave_attr_name);
473 out_unreg:
474         device_unregister(&sl->dev);
475         return err;
476 }
477
478 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
479 {
480         struct w1_slave *sl;
481         struct w1_family *f;
482         int err;
483         struct w1_netlink_msg msg;
484
485         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
486         if (!sl) {
487                 dev_err(&dev->dev,
488                          "%s: failed to allocate new slave device.\n",
489                          __func__);
490                 return -ENOMEM;
491         }
492
493         memset(sl, 0, sizeof(*sl));
494
495         sl->owner = THIS_MODULE;
496         sl->master = dev;
497         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
498
499         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
500         atomic_set(&sl->refcnt, 0);
501         init_completion(&sl->released);
502
503         spin_lock(&w1_flock);
504         f = w1_family_registered(rn->family);
505         if (!f) {
506                 f= &w1_default_family;
507                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
508                           rn->family, rn->family,
509                           (unsigned long long)rn->id, rn->crc);
510         }
511         __w1_family_get(f);
512         spin_unlock(&w1_flock);
513
514         sl->family = f;
515
516
517         err = __w1_attach_slave_device(sl);
518         if (err < 0) {
519                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
520                          sl->name);
521                 w1_family_put(sl->family);
522                 kfree(sl);
523                 return err;
524         }
525
526         sl->ttl = dev->slave_ttl;
527         dev->slave_count++;
528
529         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
530         msg.type = W1_SLAVE_ADD;
531         w1_netlink_send(dev, &msg);
532
533         return 0;
534 }
535
536 static void w1_slave_detach(struct w1_slave *sl)
537 {
538         struct w1_netlink_msg msg;
539
540         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
541
542         list_del(&sl->w1_slave_entry);
543
544         if (sl->family->fops && sl->family->fops->remove_slave)
545                 sl->family->fops->remove_slave(sl);
546
547         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
548         msg.type = W1_SLAVE_REMOVE;
549         w1_netlink_send(sl->master, &msg);
550
551         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
552         device_remove_file(&sl->dev, &w1_slave_attr_name);
553         device_unregister(&sl->dev);
554
555         wait_for_completion(&sl->released);
556         kfree(sl);
557 }
558
559 static struct w1_master *w1_search_master(void *data)
560 {
561         struct w1_master *dev;
562         int found = 0;
563
564         spin_lock_bh(&w1_mlock);
565         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
566                 if (dev->bus_master->data == data) {
567                         found = 1;
568                         atomic_inc(&dev->refcnt);
569                         break;
570                 }
571         }
572         spin_unlock_bh(&w1_mlock);
573
574         return (found)?dev:NULL;
575 }
576
577 void w1_reconnect_slaves(struct w1_family *f)
578 {
579         struct w1_master *dev;
580
581         spin_lock_bh(&w1_mlock);
582         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
583                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
584                                 dev->name, f->fid);
585                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
586         }
587         spin_unlock_bh(&w1_mlock);
588 }
589
590 static void w1_slave_found(void *data, u64 rn)
591 {
592         int slave_count;
593         struct w1_slave *sl;
594         struct list_head *ent;
595         struct w1_reg_num *tmp;
596         int family_found = 0;
597         struct w1_master *dev;
598         u64 rn_le = cpu_to_le64(rn);
599
600         dev = w1_search_master(data);
601         if (!dev) {
602                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
603                        "it is impossible.\n", data);
604                 return;
605         }
606
607         tmp = (struct w1_reg_num *) &rn;
608
609         slave_count = 0;
610         list_for_each(ent, &dev->slist) {
611
612                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
613
614                 if (sl->reg_num.family == tmp->family &&
615                     sl->reg_num.id == tmp->id &&
616                     sl->reg_num.crc == tmp->crc) {
617                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
618                         break;
619                 } else if (sl->reg_num.family == tmp->family) {
620                         family_found = 1;
621                         break;
622                 }
623
624                 slave_count++;
625         }
626
627         if (slave_count == dev->slave_count &&
628                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
629                 w1_attach_slave_device(dev, tmp);
630         }
631
632         atomic_dec(&dev->refcnt);
633 }
634
635 /**
636  * Performs a ROM Search & registers any devices found.
637  * The 1-wire search is a simple binary tree search.
638  * For each bit of the address, we read two bits and write one bit.
639  * The bit written will put to sleep all devies that don't match that bit.
640  * When the two reads differ, the direction choice is obvious.
641  * When both bits are 0, we must choose a path to take.
642  * When we can scan all 64 bits without having to choose a path, we are done.
643  *
644  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
645  *
646  * @dev        The master device to search
647  * @cb         Function to call when a device is found
648  */
649 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
650 {
651         u64 last_rn, rn, tmp64;
652         int i, slave_count = 0;
653         int last_zero, last_device;
654         int search_bit, desc_bit;
655         u8  triplet_ret = 0;
656
657         search_bit = 0;
658         rn = last_rn = 0;
659         last_device = 0;
660         last_zero = -1;
661
662         desc_bit = 64;
663
664         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
665                 last_rn = rn;
666                 rn = 0;
667
668                 /*
669                  * Reset bus and all 1-wire device state machines
670                  * so they can respond to our requests.
671                  *
672                  * Return 0 - device(s) present, 1 - no devices present.
673                  */
674                 if (w1_reset_bus(dev)) {
675                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
676                         break;
677                 }
678
679                 /* Start the search */
680                 w1_write_8(dev, W1_SEARCH);
681                 for (i = 0; i < 64; ++i) {
682                         /* Determine the direction/search bit */
683                         if (i == desc_bit)
684                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
685                         else if (i > desc_bit)
686                                 search_bit = 0;   /* take the 0 path on the next branch */
687                         else
688                                 search_bit = ((last_rn >> i) & 0x1);
689
690                         /** Read two bits and write one bit */
691                         triplet_ret = w1_triplet(dev, search_bit);
692
693                         /* quit if no device responded */
694                         if ( (triplet_ret & 0x03) == 0x03 )
695                                 break;
696
697                         /* If both directions were valid, and we took the 0 path... */
698                         if (triplet_ret == 0)
699                                 last_zero = i;
700
701                         /* extract the direction taken & update the device number */
702                         tmp64 = (triplet_ret >> 2);
703                         rn |= (tmp64 << i);
704                 }
705
706                 if ( (triplet_ret & 0x03) != 0x03 ) {
707                         if ( (desc_bit == last_zero) || (last_zero < 0))
708                                 last_device = 1;
709                         desc_bit = last_zero;
710                         cb(dev->bus_master->data, rn);
711                 }
712         }
713 }
714
715 static int w1_control(void *data)
716 {
717         struct w1_slave *sl, *sln;
718         struct w1_master *dev, *n;
719         int have_to_wait = 0;
720
721         while (!kthread_should_stop() || have_to_wait) {
722                 have_to_wait = 0;
723
724                 try_to_freeze();
725                 msleep_interruptible(w1_control_timeout * 1000);
726
727                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
728                         if (!kthread_should_stop() && !dev->flags)
729                                 continue;
730                         /*
731                          * Little race: we can create thread but not set the flag.
732                          * Get a chance for external process to set flag up.
733                          */
734                         if (!dev->initialized) {
735                                 have_to_wait = 1;
736                                 continue;
737                         }
738
739                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
740                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
741
742                                 spin_lock(&w1_mlock);
743                                 list_del(&dev->w1_master_entry);
744                                 spin_unlock(&w1_mlock);
745
746                                 down(&dev->mutex);
747                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
748                                         w1_slave_detach(sl);
749                                 }
750                                 w1_destroy_master_attributes(dev);
751                                 up(&dev->mutex);
752                                 atomic_dec(&dev->refcnt);
753                                 continue;
754                         }
755
756                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
757                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
758                                 down(&dev->mutex);
759                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
760                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
761                                                 struct w1_reg_num rn;
762
763                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
764                                                 w1_slave_detach(sl);
765
766                                                 w1_attach_slave_device(dev, &rn);
767                                         }
768                                 }
769                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
770                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
771                                 up(&dev->mutex);
772                         }
773                 }
774         }
775
776         return 0;
777 }
778
779 int w1_process(void *data)
780 {
781         struct w1_master *dev = (struct w1_master *) data;
782         struct w1_slave *sl, *sln;
783
784         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
785                 try_to_freeze();
786                 msleep_interruptible(w1_timeout * 1000);
787
788                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
789                         break;
790
791                 if (!dev->initialized)
792                         continue;
793
794                 if (dev->search_count == 0)
795                         continue;
796
797                 if (down_interruptible(&dev->mutex))
798                         continue;
799
800                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
801                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
802
803                 w1_search_devices(dev, w1_slave_found);
804
805                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
806                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
807                                 w1_slave_detach(sl);
808
809                                 dev->slave_count--;
810                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
811                                 sl->ttl = dev->slave_ttl;
812                 }
813
814                 if (dev->search_count > 0)
815                         dev->search_count--;
816
817                 up(&dev->mutex);
818         }
819
820         atomic_dec(&dev->refcnt);
821
822         return 0;
823 }
824
825 static int w1_init(void)
826 {
827         int retval;
828
829         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
830
831         retval = bus_register(&w1_bus_type);
832         if (retval) {
833                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
834                 goto err_out_exit_init;
835         }
836
837         retval = driver_register(&w1_master_driver);
838         if (retval) {
839                 printk(KERN_ERR
840                         "Failed to register master driver. err=%d.\n",
841                         retval);
842                 goto err_out_bus_unregister;
843         }
844
845         retval = driver_register(&w1_slave_driver);
846         if (retval) {
847                 printk(KERN_ERR
848                         "Failed to register master driver. err=%d.\n",
849                         retval);
850                 goto err_out_master_unregister;
851         }
852
853         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
854         if (IS_ERR(w1_control_thread)) {
855                 retval = PTR_ERR(w1_control_thread);
856                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
857                         retval);
858                 goto err_out_slave_unregister;
859         }
860
861         return 0;
862
863 err_out_slave_unregister:
864         driver_unregister(&w1_slave_driver);
865
866 err_out_master_unregister:
867         driver_unregister(&w1_master_driver);
868
869 err_out_bus_unregister:
870         bus_unregister(&w1_bus_type);
871
872 err_out_exit_init:
873         return retval;
874 }
875
876 static void w1_fini(void)
877 {
878         struct w1_master *dev;
879
880         list_for_each_entry(dev, &w1_masters, w1_master_entry)
881                 __w1_remove_master_device(dev);
882
883         kthread_stop(w1_control_thread);
884
885         driver_unregister(&w1_slave_driver);
886         driver_unregister(&w1_master_driver);
887         bus_unregister(&w1_bus_type);
888 }
889
890 module_init(w1_init);
891 module_exit(w1_fini);