[PATCH] crc16: remove w1 specific comments.
[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
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         if (md->nls && md->nls->sk_socket)
81                 sock_release(md->nls->sk_socket);
82         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
83         kfree(md);
84 }
85
86 static 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.\n", __func__, sl->name);
91
92         while (atomic_read(&sl->refcnt)) {
93                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
94                                 sl->name, atomic_read(&sl->refcnt));
95                 if (msleep_interruptible(1000))
96                         flush_signals(current);
97         }
98
99         w1_family_put(sl->family);
100         sl->master->slave_count--;
101
102         complete(&sl->released);
103 }
104
105 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
106 {
107         struct w1_slave *sl = dev_to_w1_slave(dev);
108
109         return sprintf(buf, "%s\n", sl->name);
110 }
111
112 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
113 {
114         struct w1_slave *sl = kobj_to_w1_slave(kobj);
115
116         atomic_inc(&sl->refcnt);
117         if (off > 8) {
118                 count = 0;
119         } else {
120                 if (off + count > 8)
121                         count = 8 - off;
122
123                 memcpy(buf, (u8 *)&sl->reg_num, count);
124         }
125         atomic_dec(&sl->refcnt);
126
127         return count;
128 }
129
130 static struct device_attribute w1_slave_attr_name =
131         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
132
133 static struct bin_attribute w1_slave_attr_bin_id = {
134       .attr = {
135               .name = "id",
136               .mode = S_IRUGO,
137               .owner = THIS_MODULE,
138       },
139       .size = 8,
140       .read = w1_slave_read_id,
141 };
142
143 /* Default family */
144 static struct w1_family w1_default_family;
145
146 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
147
148 static struct bus_type w1_bus_type = {
149         .name = "w1",
150         .match = w1_master_match,
151         .hotplug = w1_hotplug,
152 };
153
154 struct device_driver w1_master_driver = {
155         .name = "w1_master_driver",
156         .bus = &w1_bus_type,
157         .probe = w1_master_probe,
158 };
159
160 struct device w1_master_device = {
161         .parent = NULL,
162         .bus = &w1_bus_type,
163         .bus_id = "w1 bus master",
164         .driver = &w1_master_driver,
165         .release = &w1_master_release
166 };
167
168 struct device_driver w1_slave_driver = {
169         .name = "w1_slave_driver",
170         .bus = &w1_bus_type,
171 };
172
173 struct device w1_slave_device = {
174         .parent = NULL,
175         .bus = &w1_bus_type,
176         .bus_id = "w1 bus slave",
177         .driver = &w1_slave_driver,
178         .release = &w1_slave_release
179 };
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 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_hotplug(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 hotplug 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_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
391         if (err)
392                 return err;
393
394         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
395         if (err)
396                 return err;
397
398         return 0;
399 };
400 #else
401 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
402 {
403         return 0;
404 }
405 #endif
406
407 static int __w1_attach_slave_device(struct w1_slave *sl)
408 {
409         int err;
410
411         sl->dev.parent = &sl->master->dev;
412         sl->dev.driver = &w1_slave_driver;
413         sl->dev.bus = &w1_bus_type;
414         sl->dev.release = &w1_slave_release;
415
416         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
417                  "%02x-%012llx",
418                  (unsigned int) sl->reg_num.family,
419                  (unsigned long long) sl->reg_num.id);
420         snprintf(&sl->name[0], sizeof(sl->name),
421                  "%02x-%012llx",
422                  (unsigned int) sl->reg_num.family,
423                  (unsigned long long) sl->reg_num.id);
424
425         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
426
427         err = device_register(&sl->dev);
428         if (err < 0) {
429                 dev_err(&sl->dev,
430                         "Device registration [%s] failed. err=%d\n",
431                         sl->dev.bus_id, err);
432                 return err;
433         }
434
435         /* Create "name" entry */
436         err = device_create_file(&sl->dev, &w1_slave_attr_name);
437         if (err < 0) {
438                 dev_err(&sl->dev,
439                         "sysfs file creation for [%s] failed. err=%d\n",
440                         sl->dev.bus_id, err);
441                 goto out_unreg;
442         }
443
444         /* Create "id" entry */
445         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
446         if (err < 0) {
447                 dev_err(&sl->dev,
448                         "sysfs file creation for [%s] failed. err=%d\n",
449                         sl->dev.bus_id, err);
450                 goto out_rem1;
451         }
452
453         /* if the family driver needs to initialize something... */
454         if (sl->family->fops && sl->family->fops->add_slave &&
455             ((err = sl->family->fops->add_slave(sl)) < 0)) {
456                 dev_err(&sl->dev,
457                         "sysfs file creation for [%s] failed. err=%d\n",
458                         sl->dev.bus_id, err);
459                 goto out_rem2;
460         }
461
462         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
463
464         return 0;
465
466 out_rem2:
467         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
468 out_rem1:
469         device_remove_file(&sl->dev, &w1_slave_attr_name);
470 out_unreg:
471         device_unregister(&sl->dev);
472         return err;
473 }
474
475 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
476 {
477         struct w1_slave *sl;
478         struct w1_family *f;
479         int err;
480         struct w1_netlink_msg msg;
481
482         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
483         if (!sl) {
484                 dev_err(&dev->dev,
485                          "%s: failed to allocate new slave device.\n",
486                          __func__);
487                 return -ENOMEM;
488         }
489
490         memset(sl, 0, sizeof(*sl));
491
492         sl->owner = THIS_MODULE;
493         sl->master = dev;
494         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
495
496         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
497         atomic_set(&sl->refcnt, 0);
498         init_completion(&sl->released);
499
500         spin_lock(&w1_flock);
501         f = w1_family_registered(rn->family);
502         if (!f) {
503                 f= &w1_default_family;
504                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
505                           rn->family, rn->family,
506                           (unsigned long long)rn->id, rn->crc);
507         }
508         __w1_family_get(f);
509         spin_unlock(&w1_flock);
510
511         sl->family = f;
512
513
514         err = __w1_attach_slave_device(sl);
515         if (err < 0) {
516                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
517                          sl->name);
518                 w1_family_put(sl->family);
519                 kfree(sl);
520                 return err;
521         }
522
523         sl->ttl = dev->slave_ttl;
524         dev->slave_count++;
525
526         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
527         msg.type = W1_SLAVE_ADD;
528         w1_netlink_send(dev, &msg);
529
530         return 0;
531 }
532
533 static void w1_slave_detach(struct w1_slave *sl)
534 {
535         struct w1_netlink_msg msg;
536
537         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
538
539         list_del(&sl->w1_slave_entry);
540
541         if (sl->family->fops && sl->family->fops->remove_slave)
542                 sl->family->fops->remove_slave(sl);
543
544         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
545         msg.type = W1_SLAVE_REMOVE;
546         w1_netlink_send(sl->master, &msg);
547
548         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
549         device_remove_file(&sl->dev, &w1_slave_attr_name);
550         device_unregister(&sl->dev);
551
552         wait_for_completion(&sl->released);
553         kfree(sl);
554 }
555
556 static struct w1_master *w1_search_master(unsigned long data)
557 {
558         struct w1_master *dev;
559         int found = 0;
560
561         spin_lock_bh(&w1_mlock);
562         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
563                 if (dev->bus_master->data == data) {
564                         found = 1;
565                         atomic_inc(&dev->refcnt);
566                         break;
567                 }
568         }
569         spin_unlock_bh(&w1_mlock);
570
571         return (found)?dev:NULL;
572 }
573
574 void w1_reconnect_slaves(struct w1_family *f)
575 {
576         struct w1_master *dev;
577
578         spin_lock_bh(&w1_mlock);
579         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
580                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
581                                 dev->name, f->fid);
582                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
583         }
584         spin_unlock_bh(&w1_mlock);
585 }
586
587 static void w1_slave_found(unsigned long data, u64 rn)
588 {
589         int slave_count;
590         struct w1_slave *sl;
591         struct list_head *ent;
592         struct w1_reg_num *tmp;
593         int family_found = 0;
594         struct w1_master *dev;
595         u64 rn_le = cpu_to_le64(rn);
596
597         dev = w1_search_master(data);
598         if (!dev) {
599                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
600                                 data);
601                 return;
602         }
603
604         tmp = (struct w1_reg_num *) &rn;
605
606         slave_count = 0;
607         list_for_each(ent, &dev->slist) {
608
609                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
610
611                 if (sl->reg_num.family == tmp->family &&
612                     sl->reg_num.id == tmp->id &&
613                     sl->reg_num.crc == tmp->crc) {
614                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
615                         break;
616                 } else if (sl->reg_num.family == tmp->family) {
617                         family_found = 1;
618                         break;
619                 }
620
621                 slave_count++;
622         }
623
624         if (slave_count == dev->slave_count &&
625                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
626                 w1_attach_slave_device(dev, tmp);
627         }
628
629         atomic_dec(&dev->refcnt);
630 }
631
632 /**
633  * Performs a ROM Search & registers any devices found.
634  * The 1-wire search is a simple binary tree search.
635  * For each bit of the address, we read two bits and write one bit.
636  * The bit written will put to sleep all devies that don't match that bit.
637  * When the two reads differ, the direction choice is obvious.
638  * When both bits are 0, we must choose a path to take.
639  * When we can scan all 64 bits without having to choose a path, we are done.
640  *
641  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
642  *
643  * @dev        The master device to search
644  * @cb         Function to call when a device is found
645  */
646 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
647 {
648         u64 last_rn, rn, tmp64;
649         int i, slave_count = 0;
650         int last_zero, last_device;
651         int search_bit, desc_bit;
652         u8  triplet_ret = 0;
653
654         search_bit = 0;
655         rn = last_rn = 0;
656         last_device = 0;
657         last_zero = -1;
658
659         desc_bit = 64;
660
661         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
662                 last_rn = rn;
663                 rn = 0;
664
665                 /*
666                  * Reset bus and all 1-wire device state machines
667                  * so they can respond to our requests.
668                  *
669                  * Return 0 - device(s) present, 1 - no devices present.
670                  */
671                 if (w1_reset_bus(dev)) {
672                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
673                         break;
674                 }
675
676                 /* Start the search */
677                 w1_write_8(dev, W1_SEARCH);
678                 for (i = 0; i < 64; ++i) {
679                         /* Determine the direction/search bit */
680                         if (i == desc_bit)
681                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
682                         else if (i > desc_bit)
683                                 search_bit = 0;   /* take the 0 path on the next branch */
684                         else
685                                 search_bit = ((last_rn >> i) & 0x1);
686
687                         /** Read two bits and write one bit */
688                         triplet_ret = w1_triplet(dev, search_bit);
689
690                         /* quit if no device responded */
691                         if ( (triplet_ret & 0x03) == 0x03 )
692                                 break;
693
694                         /* If both directions were valid, and we took the 0 path... */
695                         if (triplet_ret == 0)
696                                 last_zero = i;
697
698                         /* extract the direction taken & update the device number */
699                         tmp64 = (triplet_ret >> 2);
700                         rn |= (tmp64 << i);
701                 }
702
703                 if ( (triplet_ret & 0x03) != 0x03 ) {
704                         if ( (desc_bit == last_zero) || (last_zero < 0))
705                                 last_device = 1;
706                         desc_bit = last_zero;
707                         cb(dev->bus_master->data, rn);
708                 }
709         }
710 }
711
712 static int w1_control(void *data)
713 {
714         struct w1_slave *sl, *sln;
715         struct w1_master *dev, *n;
716         int err, have_to_wait = 0;
717
718         daemonize("w1_control");
719         allow_signal(SIGTERM);
720
721         while (!control_needs_exit || have_to_wait) {
722                 have_to_wait = 0;
723
724                 try_to_freeze();
725                 msleep_interruptible(w1_control_timeout * 1000);
726
727                 if (signal_pending(current))
728                         flush_signals(current);
729
730                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
731                         if (!control_needs_exit && !dev->flags)
732                                 continue;
733                         /*
734                          * Little race: we can create thread but not set the flag.
735                          * Get a chance for external process to set flag up.
736                          */
737                         if (!dev->initialized) {
738                                 have_to_wait = 1;
739                                 continue;
740                         }
741
742                         if (control_needs_exit) {
743                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
744
745                                 err = kill_proc(dev->kpid, SIGTERM, 1);
746                                 if (err)
747                                         dev_err(&dev->dev,
748                                                  "Failed to send signal to w1 kernel thread %d.\n",
749                                                  dev->kpid);
750                         }
751
752                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
753                                 wait_for_completion(&dev->dev_exited);
754                                 spin_lock_bh(&w1_mlock);
755                                 list_del(&dev->w1_master_entry);
756                                 spin_unlock_bh(&w1_mlock);
757
758                                 down(&dev->mutex);
759                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
760                                         w1_slave_detach(sl);
761                                 }
762                                 w1_destroy_master_attributes(dev);
763                                 up(&dev->mutex);
764                                 atomic_dec(&dev->refcnt);
765                                 continue;
766                         }
767
768                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
769                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
770                                 down(&dev->mutex);
771                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
772                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
773                                                 struct w1_reg_num rn;
774
775                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
776                                                 w1_slave_detach(sl);
777
778                                                 w1_attach_slave_device(dev, &rn);
779                                         }
780                                 }
781                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
782                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
783                                 up(&dev->mutex);
784                         }
785                 }
786         }
787
788         complete_and_exit(&w1_control_complete, 0);
789 }
790
791 int w1_process(void *data)
792 {
793         struct w1_master *dev = (struct w1_master *) data;
794         struct w1_slave *sl, *sln;
795
796         daemonize("%s", dev->name);
797         allow_signal(SIGTERM);
798
799         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
800                 try_to_freeze();
801                 msleep_interruptible(w1_timeout * 1000);
802
803                 if (signal_pending(current))
804                         flush_signals(current);
805
806                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
807                         break;
808
809                 if (!dev->initialized)
810                         continue;
811
812                 if (dev->search_count == 0)
813                         continue;
814
815                 if (down_interruptible(&dev->mutex))
816                         continue;
817
818                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
819                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
820
821                 w1_search_devices(dev, w1_slave_found);
822
823                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
824                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
825                                 w1_slave_detach(sl);
826
827                                 dev->slave_count--;
828                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
829                                 sl->ttl = dev->slave_ttl;
830                 }
831
832                 if (dev->search_count > 0)
833                         dev->search_count--;
834
835                 up(&dev->mutex);
836         }
837
838         atomic_dec(&dev->refcnt);
839         complete_and_exit(&dev->dev_exited, 0);
840
841         return 0;
842 }
843
844 static int w1_init(void)
845 {
846         int retval;
847
848         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
849
850         retval = bus_register(&w1_bus_type);
851         if (retval) {
852                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
853                 goto err_out_exit_init;
854         }
855
856         retval = driver_register(&w1_master_driver);
857         if (retval) {
858                 printk(KERN_ERR
859                         "Failed to register master driver. err=%d.\n",
860                         retval);
861                 goto err_out_bus_unregister;
862         }
863
864         retval = driver_register(&w1_slave_driver);
865         if (retval) {
866                 printk(KERN_ERR
867                         "Failed to register master driver. err=%d.\n",
868                         retval);
869                 goto err_out_master_unregister;
870         }
871
872         control_thread = kernel_thread(&w1_control, NULL, 0);
873         if (control_thread < 0) {
874                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
875                         control_thread);
876                 retval = control_thread;
877                 goto err_out_slave_unregister;
878         }
879
880         return 0;
881
882 err_out_slave_unregister:
883         driver_unregister(&w1_slave_driver);
884
885 err_out_master_unregister:
886         driver_unregister(&w1_master_driver);
887
888 err_out_bus_unregister:
889         bus_unregister(&w1_bus_type);
890
891 err_out_exit_init:
892         return retval;
893 }
894
895 static void w1_fini(void)
896 {
897         struct w1_master *dev;
898
899         list_for_each_entry(dev, &w1_masters, w1_master_entry)
900                 __w1_remove_master_device(dev);
901
902         control_needs_exit = 1;
903         wait_for_completion(&w1_control_complete);
904
905         driver_unregister(&w1_slave_driver);
906         driver_unregister(&w1_master_driver);
907         bus_unregister(&w1_bus_type);
908 }
909
910 module_init(w1_init);
911 module_exit(w1_fini);