32418d4e555a0add94001c8c8d2a4db8b19308aa
[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 #include <linux/freezer.h>
35
36 #include <asm/atomic.h>
37
38 #include "w1.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 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(max_slave_count, w1_max_slave_count, int, 0);
54 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
55
56 DEFINE_MUTEX(w1_mlock);
57 LIST_HEAD(w1_masters);
58
59 static int w1_master_match(struct device *dev, struct device_driver *drv)
60 {
61         return 1;
62 }
63
64 static int w1_master_probe(struct device *dev)
65 {
66         return -ENODEV;
67 }
68
69 static void w1_master_release(struct device *dev)
70 {
71         struct w1_master *md = dev_to_w1_master(dev);
72
73         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
74         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
75         kfree(md);
76 }
77
78 static void w1_slave_release(struct device *dev)
79 {
80         struct w1_slave *sl = dev_to_w1_slave(dev);
81
82         printk("%s: Releasing %s.\n", __func__, sl->name);
83
84         while (atomic_read(&sl->refcnt)) {
85                 printk("Waiting for %s to become free: refcnt=%d.\n",
86                                 sl->name, atomic_read(&sl->refcnt));
87                 if (msleep_interruptible(1000))
88                         flush_signals(current);
89         }
90
91         w1_family_put(sl->family);
92         sl->master->slave_count--;
93
94         complete(&sl->released);
95 }
96
97 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
98 {
99         struct w1_slave *sl = dev_to_w1_slave(dev);
100
101         return sprintf(buf, "%s\n", sl->name);
102 }
103
104 static ssize_t w1_slave_read_id(struct kobject *kobj,
105                                 struct bin_attribute *bin_attr,
106                                 char *buf, loff_t off, size_t count)
107 {
108         struct w1_slave *sl = kobj_to_w1_slave(kobj);
109
110         if (off > 8) {
111                 count = 0;
112         } else {
113                 if (off + count > 8)
114                         count = 8 - off;
115
116                 memcpy(buf, (u8 *)&sl->reg_num, count);
117         }
118
119         return count;
120 }
121
122 static struct device_attribute w1_slave_attr_name =
123         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
124
125 static struct bin_attribute w1_slave_attr_bin_id = {
126       .attr = {
127               .name = "id",
128               .mode = S_IRUGO,
129       },
130       .size = 8,
131       .read = w1_slave_read_id,
132 };
133
134 /* Default family */
135
136 static ssize_t w1_default_write(struct kobject *kobj,
137                                 struct bin_attribute *bin_attr,
138                                 char *buf, loff_t off, size_t count)
139 {
140         struct w1_slave *sl = kobj_to_w1_slave(kobj);
141
142         mutex_lock(&sl->master->mutex);
143         if (w1_reset_select_slave(sl)) {
144                 count = 0;
145                 goto out_up;
146         }
147
148         w1_write_block(sl->master, buf, count);
149
150 out_up:
151         mutex_unlock(&sl->master->mutex);
152         return count;
153 }
154
155 static ssize_t w1_default_read(struct kobject *kobj,
156                                struct bin_attribute *bin_attr,
157                                char *buf, loff_t off, size_t count)
158 {
159         struct w1_slave *sl = kobj_to_w1_slave(kobj);
160
161         mutex_lock(&sl->master->mutex);
162         w1_read_block(sl->master, buf, count);
163         mutex_unlock(&sl->master->mutex);
164         return count;
165 }
166
167 static struct bin_attribute w1_default_attr = {
168       .attr = {
169               .name = "rw",
170               .mode = S_IRUGO | S_IWUSR,
171       },
172       .size = PAGE_SIZE,
173       .read = w1_default_read,
174       .write = w1_default_write,
175 };
176
177 static int w1_default_add_slave(struct w1_slave *sl)
178 {
179         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
180 }
181
182 static void w1_default_remove_slave(struct w1_slave *sl)
183 {
184         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
185 }
186
187 static struct w1_family_ops w1_default_fops = {
188         .add_slave      = w1_default_add_slave,
189         .remove_slave   = w1_default_remove_slave,
190 };
191
192 static struct w1_family w1_default_family = {
193         .fops = &w1_default_fops,
194 };
195
196 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
197
198 static struct bus_type w1_bus_type = {
199         .name = "w1",
200         .match = w1_master_match,
201         .uevent = w1_uevent,
202 };
203
204 struct device_driver w1_master_driver = {
205         .name = "w1_master_driver",
206         .bus = &w1_bus_type,
207         .probe = w1_master_probe,
208 };
209
210 struct device w1_master_device = {
211         .parent = NULL,
212         .bus = &w1_bus_type,
213         .bus_id = "w1 bus master",
214         .driver = &w1_master_driver,
215         .release = &w1_master_release
216 };
217
218 static struct device_driver w1_slave_driver = {
219         .name = "w1_slave_driver",
220         .bus = &w1_bus_type,
221 };
222
223 #if 0
224 struct device w1_slave_device = {
225         .parent = NULL,
226         .bus = &w1_bus_type,
227         .bus_id = "w1 bus slave",
228         .driver = &w1_slave_driver,
229         .release = &w1_slave_release
230 };
231 #endif  /*  0  */
232
233 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
234 {
235         struct w1_master *md = dev_to_w1_master(dev);
236         ssize_t count;
237
238         mutex_lock(&md->mutex);
239         count = sprintf(buf, "%s\n", md->name);
240         mutex_unlock(&md->mutex);
241
242         return count;
243 }
244
245 static ssize_t w1_master_attribute_store_search(struct device * dev,
246                                                 struct device_attribute *attr,
247                                                 const char * buf, size_t count)
248 {
249         long tmp;
250         struct w1_master *md = dev_to_w1_master(dev);
251
252         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
253                 return -EINVAL;
254
255         mutex_lock(&md->mutex);
256         md->search_count = tmp;
257         mutex_unlock(&md->mutex);
258         wake_up_process(md->thread);
259
260         return count;
261 }
262
263 static ssize_t w1_master_attribute_show_search(struct device *dev,
264                                                struct device_attribute *attr,
265                                                char *buf)
266 {
267         struct w1_master *md = dev_to_w1_master(dev);
268         ssize_t count;
269
270         mutex_lock(&md->mutex);
271         count = sprintf(buf, "%d\n", md->search_count);
272         mutex_unlock(&md->mutex);
273
274         return count;
275 }
276
277 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
278                                                 struct device_attribute *attr,
279                                                 const char *buf, size_t count)
280 {
281         long tmp;
282         struct w1_master *md = dev_to_w1_master(dev);
283
284         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
285                 return -EINVAL;
286
287         mutex_lock(&md->mutex);
288         md->enable_pullup = tmp;
289         mutex_unlock(&md->mutex);
290         wake_up_process(md->thread);
291
292         return count;
293 }
294
295 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
296                                                struct device_attribute *attr,
297                                                char *buf)
298 {
299         struct w1_master *md = dev_to_w1_master(dev);
300         ssize_t count;
301
302         mutex_lock(&md->mutex);
303         count = sprintf(buf, "%d\n", md->enable_pullup);
304         mutex_unlock(&md->mutex);
305
306         return count;
307 }
308
309 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
310 {
311         struct w1_master *md = dev_to_w1_master(dev);
312         ssize_t count;
313
314         mutex_lock(&md->mutex);
315         count = sprintf(buf, "0x%p\n", md->bus_master);
316         mutex_unlock(&md->mutex);
317         return count;
318 }
319
320 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
321 {
322         ssize_t count;
323         count = sprintf(buf, "%d\n", w1_timeout);
324         return count;
325 }
326
327 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
328 {
329         struct w1_master *md = dev_to_w1_master(dev);
330         ssize_t count;
331
332         mutex_lock(&md->mutex);
333         count = sprintf(buf, "%d\n", md->max_slave_count);
334         mutex_unlock(&md->mutex);
335         return count;
336 }
337
338 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
339 {
340         struct w1_master *md = dev_to_w1_master(dev);
341         ssize_t count;
342
343         mutex_lock(&md->mutex);
344         count = sprintf(buf, "%lu\n", md->attempts);
345         mutex_unlock(&md->mutex);
346         return count;
347 }
348
349 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
350 {
351         struct w1_master *md = dev_to_w1_master(dev);
352         ssize_t count;
353
354         mutex_lock(&md->mutex);
355         count = sprintf(buf, "%d\n", md->slave_count);
356         mutex_unlock(&md->mutex);
357         return count;
358 }
359
360 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
361 {
362         struct w1_master *md = dev_to_w1_master(dev);
363         int c = PAGE_SIZE;
364
365         mutex_lock(&md->mutex);
366
367         if (md->slave_count == 0)
368                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
369         else {
370                 struct list_head *ent, *n;
371                 struct w1_slave *sl;
372
373                 list_for_each_safe(ent, n, &md->slist) {
374                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
375
376                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
377                 }
378         }
379
380         mutex_unlock(&md->mutex);
381
382         return PAGE_SIZE - c;
383 }
384
385 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
386         struct device_attribute w1_master_attribute_##_name =   \
387                 __ATTR(w1_master_##_name, _mode,                \
388                        w1_master_attribute_show_##_name, NULL)
389
390 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
391         struct device_attribute w1_master_attribute_##_name =   \
392                 __ATTR(w1_master_##_name, _mode,                \
393                        w1_master_attribute_show_##_name,        \
394                        w1_master_attribute_store_##_name)
395
396 static W1_MASTER_ATTR_RO(name, S_IRUGO);
397 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
398 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
399 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
400 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
401 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
402 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
403 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
404 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUGO);
405
406 static struct attribute *w1_master_default_attrs[] = {
407         &w1_master_attribute_name.attr,
408         &w1_master_attribute_slaves.attr,
409         &w1_master_attribute_slave_count.attr,
410         &w1_master_attribute_max_slave_count.attr,
411         &w1_master_attribute_attempts.attr,
412         &w1_master_attribute_timeout.attr,
413         &w1_master_attribute_pointer.attr,
414         &w1_master_attribute_search.attr,
415         &w1_master_attribute_pullup.attr,
416         NULL
417 };
418
419 static struct attribute_group w1_master_defattr_group = {
420         .attrs = w1_master_default_attrs,
421 };
422
423 int w1_create_master_attributes(struct w1_master *master)
424 {
425         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
426 }
427
428 void w1_destroy_master_attributes(struct w1_master *master)
429 {
430         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
431 }
432
433 #ifdef CONFIG_HOTPLUG
434 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
435 {
436         struct w1_master *md = NULL;
437         struct w1_slave *sl = NULL;
438         char *event_owner, *name;
439         int err;
440
441         if (dev->driver == &w1_master_driver) {
442                 md = container_of(dev, struct w1_master, dev);
443                 event_owner = "master";
444                 name = md->name;
445         } else if (dev->driver == &w1_slave_driver) {
446                 sl = container_of(dev, struct w1_slave, dev);
447                 event_owner = "slave";
448                 name = sl->name;
449         } else {
450                 dev_dbg(dev, "Unknown event.\n");
451                 return -EINVAL;
452         }
453
454         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
455                         event_owner, name, dev->bus_id);
456
457         if (dev->driver != &w1_slave_driver || !sl)
458                 return 0;
459
460         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
461         if (err)
462                 return err;
463
464         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
465                              (unsigned long long)sl->reg_num.id);
466         if (err)
467                 return err;
468
469         return 0;
470 };
471 #else
472 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
473 {
474         return 0;
475 }
476 #endif
477
478 static int __w1_attach_slave_device(struct w1_slave *sl)
479 {
480         int err;
481
482         sl->dev.parent = &sl->master->dev;
483         sl->dev.driver = &w1_slave_driver;
484         sl->dev.bus = &w1_bus_type;
485         sl->dev.release = &w1_slave_release;
486
487         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
488                  "%02x-%012llx",
489                  (unsigned int) sl->reg_num.family,
490                  (unsigned long long) sl->reg_num.id);
491         snprintf(&sl->name[0], sizeof(sl->name),
492                  "%02x-%012llx",
493                  (unsigned int) sl->reg_num.family,
494                  (unsigned long long) sl->reg_num.id);
495
496         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
497                 &sl->dev.bus_id[0], sl);
498
499         err = device_register(&sl->dev);
500         if (err < 0) {
501                 dev_err(&sl->dev,
502                         "Device registration [%s] failed. err=%d\n",
503                         sl->dev.bus_id, err);
504                 return err;
505         }
506
507         /* Create "name" entry */
508         err = device_create_file(&sl->dev, &w1_slave_attr_name);
509         if (err < 0) {
510                 dev_err(&sl->dev,
511                         "sysfs file creation for [%s] failed. err=%d\n",
512                         sl->dev.bus_id, err);
513                 goto out_unreg;
514         }
515
516         /* Create "id" entry */
517         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
518         if (err < 0) {
519                 dev_err(&sl->dev,
520                         "sysfs file creation for [%s] failed. err=%d\n",
521                         sl->dev.bus_id, err);
522                 goto out_rem1;
523         }
524
525         /* if the family driver needs to initialize something... */
526         if (sl->family->fops && sl->family->fops->add_slave &&
527             ((err = sl->family->fops->add_slave(sl)) < 0)) {
528                 dev_err(&sl->dev,
529                         "sysfs file creation for [%s] failed. err=%d\n",
530                         sl->dev.bus_id, err);
531                 goto out_rem2;
532         }
533
534         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
535
536         return 0;
537
538 out_rem2:
539         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
540 out_rem1:
541         device_remove_file(&sl->dev, &w1_slave_attr_name);
542 out_unreg:
543         device_unregister(&sl->dev);
544         return err;
545 }
546
547 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
548 {
549         struct w1_slave *sl;
550         struct w1_family *f;
551         int err;
552         struct w1_netlink_msg msg;
553
554         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
555         if (!sl) {
556                 dev_err(&dev->dev,
557                          "%s: failed to allocate new slave device.\n",
558                          __func__);
559                 return -ENOMEM;
560         }
561
562
563         sl->owner = THIS_MODULE;
564         sl->master = dev;
565         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
566
567         memset(&msg, 0, sizeof(msg));
568         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
569         atomic_set(&sl->refcnt, 0);
570         init_completion(&sl->released);
571
572         spin_lock(&w1_flock);
573         f = w1_family_registered(rn->family);
574         if (!f) {
575                 f= &w1_default_family;
576                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
577                           rn->family, rn->family,
578                           (unsigned long long)rn->id, rn->crc);
579         }
580         __w1_family_get(f);
581         spin_unlock(&w1_flock);
582
583         sl->family = f;
584
585
586         err = __w1_attach_slave_device(sl);
587         if (err < 0) {
588                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
589                          sl->name);
590                 w1_family_put(sl->family);
591                 kfree(sl);
592                 return err;
593         }
594
595         sl->ttl = dev->slave_ttl;
596         dev->slave_count++;
597
598         memcpy(msg.id.id, rn, sizeof(msg.id));
599         msg.type = W1_SLAVE_ADD;
600         w1_netlink_send(dev, &msg);
601
602         return 0;
603 }
604
605 void w1_slave_detach(struct w1_slave *sl)
606 {
607         struct w1_netlink_msg msg;
608
609         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
610
611         list_del(&sl->w1_slave_entry);
612
613         if (sl->family->fops && sl->family->fops->remove_slave)
614                 sl->family->fops->remove_slave(sl);
615
616         memset(&msg, 0, sizeof(msg));
617         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
618         msg.type = W1_SLAVE_REMOVE;
619         w1_netlink_send(sl->master, &msg);
620
621         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
622         device_remove_file(&sl->dev, &w1_slave_attr_name);
623         device_unregister(&sl->dev);
624
625         wait_for_completion(&sl->released);
626         kfree(sl);
627 }
628
629 struct w1_master *w1_search_master_id(u32 id)
630 {
631         struct w1_master *dev;
632         int found = 0;
633
634         mutex_lock(&w1_mlock);
635         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
636                 if (dev->id == id) {
637                         found = 1;
638                         atomic_inc(&dev->refcnt);
639                         break;
640                 }
641         }
642         mutex_unlock(&w1_mlock);
643
644         return (found)?dev:NULL;
645 }
646
647 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
648 {
649         struct w1_master *dev;
650         struct w1_slave *sl = NULL;
651         int found = 0;
652
653         mutex_lock(&w1_mlock);
654         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
655                 mutex_lock(&dev->mutex);
656                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
657                         if (sl->reg_num.family == id->family &&
658                                         sl->reg_num.id == id->id &&
659                                         sl->reg_num.crc == id->crc) {
660                                 found = 1;
661                                 atomic_inc(&dev->refcnt);
662                                 atomic_inc(&sl->refcnt);
663                                 break;
664                         }
665                 }
666                 mutex_unlock(&dev->mutex);
667
668                 if (found)
669                         break;
670         }
671         mutex_unlock(&w1_mlock);
672
673         return (found)?sl:NULL;
674 }
675
676 void w1_reconnect_slaves(struct w1_family *f, int attach)
677 {
678         struct w1_slave *sl, *sln;
679         struct w1_master *dev;
680
681         mutex_lock(&w1_mlock);
682         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
683                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
684                         "for family %02x.\n", dev->name, f->fid);
685                 mutex_lock(&dev->mutex);
686                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
687                         /* If it is a new family, slaves with the default
688                          * family driver and are that family will be
689                          * connected.  If the family is going away, devices
690                          * matching that family are reconneced.
691                          */
692                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
693                                 && sl->reg_num.family == f->fid) ||
694                                 (!attach && sl->family->fid == f->fid)) {
695                                 struct w1_reg_num rn;
696
697                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
698                                 w1_slave_detach(sl);
699
700                                 w1_attach_slave_device(dev, &rn);
701                         }
702                 }
703                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
704                         "has been finished.\n", dev->name);
705                 mutex_unlock(&dev->mutex);
706         }
707         mutex_unlock(&w1_mlock);
708 }
709
710 static void w1_slave_found(struct w1_master *dev, u64 rn)
711 {
712         int slave_count;
713         struct w1_slave *sl;
714         struct list_head *ent;
715         struct w1_reg_num *tmp;
716         u64 rn_le = cpu_to_le64(rn);
717
718         atomic_inc(&dev->refcnt);
719
720         tmp = (struct w1_reg_num *) &rn;
721
722         slave_count = 0;
723         list_for_each(ent, &dev->slist) {
724
725                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
726
727                 if (sl->reg_num.family == tmp->family &&
728                     sl->reg_num.id == tmp->id &&
729                     sl->reg_num.crc == tmp->crc) {
730                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
731                         break;
732                 }
733
734                 slave_count++;
735         }
736
737         if (slave_count == dev->slave_count &&
738                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
739                 w1_attach_slave_device(dev, tmp);
740         }
741
742         atomic_dec(&dev->refcnt);
743 }
744
745 /**
746  * Performs a ROM Search & registers any devices found.
747  * The 1-wire search is a simple binary tree search.
748  * For each bit of the address, we read two bits and write one bit.
749  * The bit written will put to sleep all devies that don't match that bit.
750  * When the two reads differ, the direction choice is obvious.
751  * When both bits are 0, we must choose a path to take.
752  * When we can scan all 64 bits without having to choose a path, we are done.
753  *
754  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
755  *
756  * @dev        The master device to search
757  * @cb         Function to call when a device is found
758  */
759 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
760 {
761         u64 last_rn, rn, tmp64;
762         int i, slave_count = 0;
763         int last_zero, last_device;
764         int search_bit, desc_bit;
765         u8  triplet_ret = 0;
766
767         search_bit = 0;
768         rn = last_rn = 0;
769         last_device = 0;
770         last_zero = -1;
771
772         desc_bit = 64;
773
774         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
775                 last_rn = rn;
776                 rn = 0;
777
778                 /*
779                  * Reset bus and all 1-wire device state machines
780                  * so they can respond to our requests.
781                  *
782                  * Return 0 - device(s) present, 1 - no devices present.
783                  */
784                 if (w1_reset_bus(dev)) {
785                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
786                         break;
787                 }
788
789                 /* Start the search */
790                 w1_write_8(dev, search_type);
791                 for (i = 0; i < 64; ++i) {
792                         /* Determine the direction/search bit */
793                         if (i == desc_bit)
794                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
795                         else if (i > desc_bit)
796                                 search_bit = 0;   /* take the 0 path on the next branch */
797                         else
798                                 search_bit = ((last_rn >> i) & 0x1);
799
800                         /** Read two bits and write one bit */
801                         triplet_ret = w1_triplet(dev, search_bit);
802
803                         /* quit if no device responded */
804                         if ( (triplet_ret & 0x03) == 0x03 )
805                                 break;
806
807                         /* If both directions were valid, and we took the 0 path... */
808                         if (triplet_ret == 0)
809                                 last_zero = i;
810
811                         /* extract the direction taken & update the device number */
812                         tmp64 = (triplet_ret >> 2);
813                         rn |= (tmp64 << i);
814
815                         if (kthread_should_stop()) {
816                                 printk(KERN_INFO "Abort w1_search (exiting)\n");
817                                 return;
818                         }
819                 }
820
821                 if ( (triplet_ret & 0x03) != 0x03 ) {
822                         if ( (desc_bit == last_zero) || (last_zero < 0))
823                                 last_device = 1;
824                         desc_bit = last_zero;
825                         cb(dev, rn);
826                 }
827         }
828 }
829
830 void w1_search_process(struct w1_master *dev, u8 search_type)
831 {
832         struct w1_slave *sl, *sln;
833
834         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
835                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
836
837         w1_search_devices(dev, search_type, w1_slave_found);
838
839         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
840                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
841                         w1_slave_detach(sl);
842                 else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
843                         sl->ttl = dev->slave_ttl;
844         }
845
846         if (dev->search_count > 0)
847                 dev->search_count--;
848 }
849
850 int w1_process(void *data)
851 {
852         struct w1_master *dev = (struct w1_master *) data;
853         /* As long as w1_timeout is only set by a module parameter the sleep
854          * time can be calculated in jiffies once.
855          */
856         const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
857
858         while (!kthread_should_stop()) {
859                 if (dev->search_count) {
860                         mutex_lock(&dev->mutex);
861                         w1_search_process(dev, W1_SEARCH);
862                         mutex_unlock(&dev->mutex);
863                 }
864
865                 try_to_freeze();
866                 __set_current_state(TASK_INTERRUPTIBLE);
867
868                 if (kthread_should_stop())
869                         break;
870
871                 /* Only sleep when the search is active. */
872                 if (dev->search_count)
873                         schedule_timeout(jtime);
874                 else
875                         schedule();
876         }
877
878         atomic_dec(&dev->refcnt);
879
880         return 0;
881 }
882
883 static int w1_init(void)
884 {
885         int retval;
886
887         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
888
889         w1_init_netlink();
890
891         retval = bus_register(&w1_bus_type);
892         if (retval) {
893                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
894                 goto err_out_exit_init;
895         }
896
897         retval = driver_register(&w1_master_driver);
898         if (retval) {
899                 printk(KERN_ERR
900                         "Failed to register master driver. err=%d.\n",
901                         retval);
902                 goto err_out_bus_unregister;
903         }
904
905         retval = driver_register(&w1_slave_driver);
906         if (retval) {
907                 printk(KERN_ERR
908                         "Failed to register master driver. err=%d.\n",
909                         retval);
910                 goto err_out_master_unregister;
911         }
912
913         return 0;
914
915 #if 0
916 /* For undoing the slave register if there was a step after it. */
917 err_out_slave_unregister:
918         driver_unregister(&w1_slave_driver);
919 #endif
920
921 err_out_master_unregister:
922         driver_unregister(&w1_master_driver);
923
924 err_out_bus_unregister:
925         bus_unregister(&w1_bus_type);
926
927 err_out_exit_init:
928         return retval;
929 }
930
931 static void w1_fini(void)
932 {
933         struct w1_master *dev;
934
935         /* Set netlink removal messages and some cleanup */
936         list_for_each_entry(dev, &w1_masters, w1_master_entry)
937                 __w1_remove_master_device(dev);
938
939         w1_fini_netlink();
940
941         driver_unregister(&w1_slave_driver);
942         driver_unregister(&w1_master_driver);
943         bus_unregister(&w1_bus_type);
944 }
945
946 module_init(w1_init);
947 module_exit(w1_fini);