W1: recode w1_slave_found logic
[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_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
60
61 static int w1_master_match(struct device *dev, struct device_driver *drv)
62 {
63         return 1;
64 }
65
66 static int w1_master_probe(struct device *dev)
67 {
68         return -ENODEV;
69 }
70
71 static void w1_master_release(struct device *dev)
72 {
73         struct w1_master *md = dev_to_w1_master(dev);
74
75         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
76         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
77         kfree(md);
78 }
79
80 static void w1_slave_release(struct device *dev)
81 {
82         struct w1_slave *sl = dev_to_w1_slave(dev);
83
84         printk("%s: Releasing %s.\n", __func__, sl->name);
85
86         while (atomic_read(&sl->refcnt)) {
87                 printk("Waiting for %s to become free: refcnt=%d.\n",
88                                 sl->name, atomic_read(&sl->refcnt));
89                 if (msleep_interruptible(1000))
90                         flush_signals(current);
91         }
92
93         w1_family_put(sl->family);
94         sl->master->slave_count--;
95
96         complete(&sl->released);
97 }
98
99 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
100 {
101         struct w1_slave *sl = dev_to_w1_slave(dev);
102
103         return sprintf(buf, "%s\n", sl->name);
104 }
105
106 static ssize_t w1_slave_read_id(struct kobject *kobj,
107                                 struct bin_attribute *bin_attr,
108                                 char *buf, loff_t off, size_t count)
109 {
110         struct w1_slave *sl = kobj_to_w1_slave(kobj);
111
112         if (off > 8) {
113                 count = 0;
114         } else {
115                 if (off + count > 8)
116                         count = 8 - off;
117
118                 memcpy(buf, (u8 *)&sl->reg_num, count);
119         }
120
121         return count;
122 }
123
124 static struct device_attribute w1_slave_attr_name =
125         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
126
127 static struct bin_attribute w1_slave_attr_bin_id = {
128       .attr = {
129               .name = "id",
130               .mode = S_IRUGO,
131       },
132       .size = 8,
133       .read = w1_slave_read_id,
134 };
135
136 /* Default family */
137
138 static ssize_t w1_default_write(struct kobject *kobj,
139                                 struct bin_attribute *bin_attr,
140                                 char *buf, loff_t off, size_t count)
141 {
142         struct w1_slave *sl = kobj_to_w1_slave(kobj);
143
144         mutex_lock(&sl->master->mutex);
145         if (w1_reset_select_slave(sl)) {
146                 count = 0;
147                 goto out_up;
148         }
149
150         w1_write_block(sl->master, buf, count);
151
152 out_up:
153         mutex_unlock(&sl->master->mutex);
154         return count;
155 }
156
157 static ssize_t w1_default_read(struct kobject *kobj,
158                                struct bin_attribute *bin_attr,
159                                char *buf, loff_t off, size_t count)
160 {
161         struct w1_slave *sl = kobj_to_w1_slave(kobj);
162
163         mutex_lock(&sl->master->mutex);
164         w1_read_block(sl->master, buf, count);
165         mutex_unlock(&sl->master->mutex);
166         return count;
167 }
168
169 static struct bin_attribute w1_default_attr = {
170       .attr = {
171               .name = "rw",
172               .mode = S_IRUGO | S_IWUSR,
173       },
174       .size = PAGE_SIZE,
175       .read = w1_default_read,
176       .write = w1_default_write,
177 };
178
179 static int w1_default_add_slave(struct w1_slave *sl)
180 {
181         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
182 }
183
184 static void w1_default_remove_slave(struct w1_slave *sl)
185 {
186         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
187 }
188
189 static struct w1_family_ops w1_default_fops = {
190         .add_slave      = w1_default_add_slave,
191         .remove_slave   = w1_default_remove_slave,
192 };
193
194 static struct w1_family w1_default_family = {
195         .fops = &w1_default_fops,
196 };
197
198 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
199
200 static struct bus_type w1_bus_type = {
201         .name = "w1",
202         .match = w1_master_match,
203         .uevent = w1_uevent,
204 };
205
206 struct device_driver w1_master_driver = {
207         .name = "w1_master_driver",
208         .bus = &w1_bus_type,
209         .probe = w1_master_probe,
210 };
211
212 struct device w1_master_device = {
213         .parent = NULL,
214         .bus = &w1_bus_type,
215         .bus_id = "w1 bus master",
216         .driver = &w1_master_driver,
217         .release = &w1_master_release
218 };
219
220 static struct device_driver w1_slave_driver = {
221         .name = "w1_slave_driver",
222         .bus = &w1_bus_type,
223 };
224
225 #if 0
226 struct device w1_slave_device = {
227         .parent = NULL,
228         .bus = &w1_bus_type,
229         .bus_id = "w1 bus slave",
230         .driver = &w1_slave_driver,
231         .release = &w1_slave_release
232 };
233 #endif  /*  0  */
234
235 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
236 {
237         struct w1_master *md = dev_to_w1_master(dev);
238         ssize_t count;
239
240         mutex_lock(&md->mutex);
241         count = sprintf(buf, "%s\n", md->name);
242         mutex_unlock(&md->mutex);
243
244         return count;
245 }
246
247 static ssize_t w1_master_attribute_store_search(struct device * dev,
248                                                 struct device_attribute *attr,
249                                                 const char * buf, size_t count)
250 {
251         long tmp;
252         struct w1_master *md = dev_to_w1_master(dev);
253
254         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
255                 return -EINVAL;
256
257         mutex_lock(&md->mutex);
258         md->search_count = tmp;
259         mutex_unlock(&md->mutex);
260         wake_up_process(md->thread);
261
262         return count;
263 }
264
265 static ssize_t w1_master_attribute_show_search(struct device *dev,
266                                                struct device_attribute *attr,
267                                                char *buf)
268 {
269         struct w1_master *md = dev_to_w1_master(dev);
270         ssize_t count;
271
272         mutex_lock(&md->mutex);
273         count = sprintf(buf, "%d\n", md->search_count);
274         mutex_unlock(&md->mutex);
275
276         return count;
277 }
278
279 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
280                                                 struct device_attribute *attr,
281                                                 const char *buf, size_t count)
282 {
283         long tmp;
284         struct w1_master *md = dev_to_w1_master(dev);
285
286         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
287                 return -EINVAL;
288
289         mutex_lock(&md->mutex);
290         md->enable_pullup = tmp;
291         mutex_unlock(&md->mutex);
292         wake_up_process(md->thread);
293
294         return count;
295 }
296
297 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
298                                                struct device_attribute *attr,
299                                                char *buf)
300 {
301         struct w1_master *md = dev_to_w1_master(dev);
302         ssize_t count;
303
304         mutex_lock(&md->mutex);
305         count = sprintf(buf, "%d\n", md->enable_pullup);
306         mutex_unlock(&md->mutex);
307
308         return count;
309 }
310
311 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
312 {
313         struct w1_master *md = dev_to_w1_master(dev);
314         ssize_t count;
315
316         mutex_lock(&md->mutex);
317         count = sprintf(buf, "0x%p\n", md->bus_master);
318         mutex_unlock(&md->mutex);
319         return count;
320 }
321
322 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
323 {
324         ssize_t count;
325         count = sprintf(buf, "%d\n", w1_timeout);
326         return count;
327 }
328
329 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
330 {
331         struct w1_master *md = dev_to_w1_master(dev);
332         ssize_t count;
333
334         mutex_lock(&md->mutex);
335         count = sprintf(buf, "%d\n", md->max_slave_count);
336         mutex_unlock(&md->mutex);
337         return count;
338 }
339
340 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
341 {
342         struct w1_master *md = dev_to_w1_master(dev);
343         ssize_t count;
344
345         mutex_lock(&md->mutex);
346         count = sprintf(buf, "%lu\n", md->attempts);
347         mutex_unlock(&md->mutex);
348         return count;
349 }
350
351 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
352 {
353         struct w1_master *md = dev_to_w1_master(dev);
354         ssize_t count;
355
356         mutex_lock(&md->mutex);
357         count = sprintf(buf, "%d\n", md->slave_count);
358         mutex_unlock(&md->mutex);
359         return count;
360 }
361
362 static ssize_t w1_master_attribute_show_slaves(struct device *dev,
363         struct device_attribute *attr, char *buf)
364 {
365         struct w1_master *md = dev_to_w1_master(dev);
366         int c = PAGE_SIZE;
367
368         mutex_lock(&md->mutex);
369
370         if (md->slave_count == 0)
371                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
372         else {
373                 struct list_head *ent, *n;
374                 struct w1_slave *sl;
375
376                 list_for_each_safe(ent, n, &md->slist) {
377                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
378
379                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
380                 }
381         }
382
383         mutex_unlock(&md->mutex);
384
385         return PAGE_SIZE - c;
386 }
387
388 static ssize_t w1_master_attribute_show_add(struct device *dev,
389         struct device_attribute *attr, char *buf)
390 {
391         int c = PAGE_SIZE;
392         c -= snprintf(buf+PAGE_SIZE - c, c,
393                 "write device id xx-xxxxxxxxxxxx to add slave\n");
394         return PAGE_SIZE - c;
395 }
396
397 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
398         struct w1_reg_num *rn)
399 {
400         unsigned int family;
401         unsigned long long id;
402         int i;
403         u64 rn64_le;
404
405         /* The CRC value isn't read from the user because the sysfs directory
406          * doesn't include it and most messages from the bus search don't
407          * print it either.  It would be unreasonable for the user to then
408          * provide it.
409          */
410         const char *error_msg = "bad slave string format, expecting "
411                 "ff-dddddddddddd\n";
412
413         if (buf[2] != '-') {
414                 dev_err(dev, "%s", error_msg);
415                 return -EINVAL;
416         }
417         i = sscanf(buf, "%02x-%012llx", &family, &id);
418         if (i != 2) {
419                 dev_err(dev, "%s", error_msg);
420                 return -EINVAL;
421         }
422         rn->family = family;
423         rn->id = id;
424
425         rn64_le = cpu_to_le64(*(u64 *)rn);
426         rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
427
428 #if 0
429         dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
430                   rn->family, (unsigned long long)rn->id, rn->crc);
431 #endif
432
433         return 0;
434 }
435
436 /* Searches the slaves in the w1_master and returns a pointer or NULL.
437  * Note: must hold the mutex
438  */
439 static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
440         struct w1_reg_num *rn)
441 {
442         struct w1_slave *sl;
443         list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
444                 if (sl->reg_num.family == rn->family &&
445                                 sl->reg_num.id == rn->id &&
446                                 sl->reg_num.crc == rn->crc) {
447                         return sl;
448                 }
449         }
450         return NULL;
451 }
452
453 static ssize_t w1_master_attribute_store_add(struct device *dev,
454                                                 struct device_attribute *attr,
455                                                 const char *buf, size_t count)
456 {
457         struct w1_master *md = dev_to_w1_master(dev);
458         struct w1_reg_num rn;
459         struct w1_slave *sl;
460         ssize_t result = count;
461
462         if (w1_atoreg_num(dev, buf, count, &rn))
463                 return -EINVAL;
464
465         mutex_lock(&md->mutex);
466         sl = w1_slave_search_device(md, &rn);
467         /* It would be nice to do a targeted search one the one-wire bus
468          * for the new device to see if it is out there or not.  But the
469          * current search doesn't support that.
470          */
471         if (sl) {
472                 dev_info(dev, "Device %s already exists\n", sl->name);
473                 result = -EINVAL;
474         } else {
475                 w1_attach_slave_device(md, &rn);
476         }
477         mutex_unlock(&md->mutex);
478
479         return result;
480 }
481
482 static ssize_t w1_master_attribute_show_remove(struct device *dev,
483         struct device_attribute *attr, char *buf)
484 {
485         int c = PAGE_SIZE;
486         c -= snprintf(buf+PAGE_SIZE - c, c,
487                 "write device id xx-xxxxxxxxxxxx to remove slave\n");
488         return PAGE_SIZE - c;
489 }
490
491 static ssize_t w1_master_attribute_store_remove(struct device *dev,
492                                                 struct device_attribute *attr,
493                                                 const char *buf, size_t count)
494 {
495         struct w1_master *md = dev_to_w1_master(dev);
496         struct w1_reg_num rn;
497         struct w1_slave *sl;
498         ssize_t result = count;
499
500         if (w1_atoreg_num(dev, buf, count, &rn))
501                 return -EINVAL;
502
503         mutex_lock(&md->mutex);
504         sl = w1_slave_search_device(md, &rn);
505         if (sl) {
506                 w1_slave_detach(sl);
507         } else {
508                 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
509                         (unsigned long long)rn.id);
510                 result = -EINVAL;
511         }
512         mutex_unlock(&md->mutex);
513
514         return result;
515 }
516
517 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
518         struct device_attribute w1_master_attribute_##_name =   \
519                 __ATTR(w1_master_##_name, _mode,                \
520                        w1_master_attribute_show_##_name, NULL)
521
522 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
523         struct device_attribute w1_master_attribute_##_name =   \
524                 __ATTR(w1_master_##_name, _mode,                \
525                        w1_master_attribute_show_##_name,        \
526                        w1_master_attribute_store_##_name)
527
528 static W1_MASTER_ATTR_RO(name, S_IRUGO);
529 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
530 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
531 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
532 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
533 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
534 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
535 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
536 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUGO);
537 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUGO);
538 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUGO);
539
540 static struct attribute *w1_master_default_attrs[] = {
541         &w1_master_attribute_name.attr,
542         &w1_master_attribute_slaves.attr,
543         &w1_master_attribute_slave_count.attr,
544         &w1_master_attribute_max_slave_count.attr,
545         &w1_master_attribute_attempts.attr,
546         &w1_master_attribute_timeout.attr,
547         &w1_master_attribute_pointer.attr,
548         &w1_master_attribute_search.attr,
549         &w1_master_attribute_pullup.attr,
550         &w1_master_attribute_add.attr,
551         &w1_master_attribute_remove.attr,
552         NULL
553 };
554
555 static struct attribute_group w1_master_defattr_group = {
556         .attrs = w1_master_default_attrs,
557 };
558
559 int w1_create_master_attributes(struct w1_master *master)
560 {
561         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
562 }
563
564 void w1_destroy_master_attributes(struct w1_master *master)
565 {
566         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
567 }
568
569 #ifdef CONFIG_HOTPLUG
570 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
571 {
572         struct w1_master *md = NULL;
573         struct w1_slave *sl = NULL;
574         char *event_owner, *name;
575         int err;
576
577         if (dev->driver == &w1_master_driver) {
578                 md = container_of(dev, struct w1_master, dev);
579                 event_owner = "master";
580                 name = md->name;
581         } else if (dev->driver == &w1_slave_driver) {
582                 sl = container_of(dev, struct w1_slave, dev);
583                 event_owner = "slave";
584                 name = sl->name;
585         } else {
586                 dev_dbg(dev, "Unknown event.\n");
587                 return -EINVAL;
588         }
589
590         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
591                         event_owner, name, dev->bus_id);
592
593         if (dev->driver != &w1_slave_driver || !sl)
594                 return 0;
595
596         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
597         if (err)
598                 return err;
599
600         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
601                              (unsigned long long)sl->reg_num.id);
602         if (err)
603                 return err;
604
605         return 0;
606 };
607 #else
608 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
609 {
610         return 0;
611 }
612 #endif
613
614 static int __w1_attach_slave_device(struct w1_slave *sl)
615 {
616         int err;
617
618         sl->dev.parent = &sl->master->dev;
619         sl->dev.driver = &w1_slave_driver;
620         sl->dev.bus = &w1_bus_type;
621         sl->dev.release = &w1_slave_release;
622
623         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
624                  "%02x-%012llx",
625                  (unsigned int) sl->reg_num.family,
626                  (unsigned long long) sl->reg_num.id);
627         snprintf(&sl->name[0], sizeof(sl->name),
628                  "%02x-%012llx",
629                  (unsigned int) sl->reg_num.family,
630                  (unsigned long long) sl->reg_num.id);
631
632         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
633                 &sl->dev.bus_id[0], sl);
634
635         err = device_register(&sl->dev);
636         if (err < 0) {
637                 dev_err(&sl->dev,
638                         "Device registration [%s] failed. err=%d\n",
639                         sl->dev.bus_id, err);
640                 return err;
641         }
642
643         /* Create "name" entry */
644         err = device_create_file(&sl->dev, &w1_slave_attr_name);
645         if (err < 0) {
646                 dev_err(&sl->dev,
647                         "sysfs file creation for [%s] failed. err=%d\n",
648                         sl->dev.bus_id, err);
649                 goto out_unreg;
650         }
651
652         /* Create "id" entry */
653         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
654         if (err < 0) {
655                 dev_err(&sl->dev,
656                         "sysfs file creation for [%s] failed. err=%d\n",
657                         sl->dev.bus_id, err);
658                 goto out_rem1;
659         }
660
661         /* if the family driver needs to initialize something... */
662         if (sl->family->fops && sl->family->fops->add_slave &&
663             ((err = sl->family->fops->add_slave(sl)) < 0)) {
664                 dev_err(&sl->dev,
665                         "sysfs file creation for [%s] failed. err=%d\n",
666                         sl->dev.bus_id, err);
667                 goto out_rem2;
668         }
669
670         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
671
672         return 0;
673
674 out_rem2:
675         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
676 out_rem1:
677         device_remove_file(&sl->dev, &w1_slave_attr_name);
678 out_unreg:
679         device_unregister(&sl->dev);
680         return err;
681 }
682
683 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
684 {
685         struct w1_slave *sl;
686         struct w1_family *f;
687         int err;
688         struct w1_netlink_msg msg;
689
690         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
691         if (!sl) {
692                 dev_err(&dev->dev,
693                          "%s: failed to allocate new slave device.\n",
694                          __func__);
695                 return -ENOMEM;
696         }
697
698
699         sl->owner = THIS_MODULE;
700         sl->master = dev;
701         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
702
703         memset(&msg, 0, sizeof(msg));
704         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
705         atomic_set(&sl->refcnt, 0);
706         init_completion(&sl->released);
707
708         spin_lock(&w1_flock);
709         f = w1_family_registered(rn->family);
710         if (!f) {
711                 f= &w1_default_family;
712                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
713                           rn->family, rn->family,
714                           (unsigned long long)rn->id, rn->crc);
715         }
716         __w1_family_get(f);
717         spin_unlock(&w1_flock);
718
719         sl->family = f;
720
721
722         err = __w1_attach_slave_device(sl);
723         if (err < 0) {
724                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
725                          sl->name);
726                 w1_family_put(sl->family);
727                 kfree(sl);
728                 return err;
729         }
730
731         sl->ttl = dev->slave_ttl;
732         dev->slave_count++;
733
734         memcpy(msg.id.id, rn, sizeof(msg.id));
735         msg.type = W1_SLAVE_ADD;
736         w1_netlink_send(dev, &msg);
737
738         return 0;
739 }
740
741 void w1_slave_detach(struct w1_slave *sl)
742 {
743         struct w1_netlink_msg msg;
744
745         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
746
747         list_del(&sl->w1_slave_entry);
748
749         if (sl->family->fops && sl->family->fops->remove_slave)
750                 sl->family->fops->remove_slave(sl);
751
752         memset(&msg, 0, sizeof(msg));
753         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
754         msg.type = W1_SLAVE_REMOVE;
755         w1_netlink_send(sl->master, &msg);
756
757         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
758         device_remove_file(&sl->dev, &w1_slave_attr_name);
759         device_unregister(&sl->dev);
760
761         wait_for_completion(&sl->released);
762         kfree(sl);
763 }
764
765 struct w1_master *w1_search_master_id(u32 id)
766 {
767         struct w1_master *dev;
768         int found = 0;
769
770         mutex_lock(&w1_mlock);
771         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
772                 if (dev->id == id) {
773                         found = 1;
774                         atomic_inc(&dev->refcnt);
775                         break;
776                 }
777         }
778         mutex_unlock(&w1_mlock);
779
780         return (found)?dev:NULL;
781 }
782
783 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
784 {
785         struct w1_master *dev;
786         struct w1_slave *sl = NULL;
787         int found = 0;
788
789         mutex_lock(&w1_mlock);
790         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
791                 mutex_lock(&dev->mutex);
792                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
793                         if (sl->reg_num.family == id->family &&
794                                         sl->reg_num.id == id->id &&
795                                         sl->reg_num.crc == id->crc) {
796                                 found = 1;
797                                 atomic_inc(&dev->refcnt);
798                                 atomic_inc(&sl->refcnt);
799                                 break;
800                         }
801                 }
802                 mutex_unlock(&dev->mutex);
803
804                 if (found)
805                         break;
806         }
807         mutex_unlock(&w1_mlock);
808
809         return (found)?sl:NULL;
810 }
811
812 void w1_reconnect_slaves(struct w1_family *f, int attach)
813 {
814         struct w1_slave *sl, *sln;
815         struct w1_master *dev;
816
817         mutex_lock(&w1_mlock);
818         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
819                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
820                         "for family %02x.\n", dev->name, f->fid);
821                 mutex_lock(&dev->mutex);
822                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
823                         /* If it is a new family, slaves with the default
824                          * family driver and are that family will be
825                          * connected.  If the family is going away, devices
826                          * matching that family are reconneced.
827                          */
828                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
829                                 && sl->reg_num.family == f->fid) ||
830                                 (!attach && sl->family->fid == f->fid)) {
831                                 struct w1_reg_num rn;
832
833                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
834                                 w1_slave_detach(sl);
835
836                                 w1_attach_slave_device(dev, &rn);
837                         }
838                 }
839                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
840                         "has been finished.\n", dev->name);
841                 mutex_unlock(&dev->mutex);
842         }
843         mutex_unlock(&w1_mlock);
844 }
845
846 static void w1_slave_found(struct w1_master *dev, u64 rn)
847 {
848         struct w1_slave *sl;
849         struct w1_reg_num *tmp;
850         u64 rn_le = cpu_to_le64(rn);
851
852         atomic_inc(&dev->refcnt);
853
854         tmp = (struct w1_reg_num *) &rn;
855
856         sl = w1_slave_search_device(dev, tmp);
857         if (sl) {
858                 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
859         } else {
860                 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
861                         w1_attach_slave_device(dev, tmp);
862         }
863
864         atomic_dec(&dev->refcnt);
865 }
866
867 /**
868  * Performs a ROM Search & registers any devices found.
869  * The 1-wire search is a simple binary tree search.
870  * For each bit of the address, we read two bits and write one bit.
871  * The bit written will put to sleep all devies that don't match that bit.
872  * When the two reads differ, the direction choice is obvious.
873  * When both bits are 0, we must choose a path to take.
874  * When we can scan all 64 bits without having to choose a path, we are done.
875  *
876  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
877  *
878  * @dev        The master device to search
879  * @cb         Function to call when a device is found
880  */
881 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
882 {
883         u64 last_rn, rn, tmp64;
884         int i, slave_count = 0;
885         int last_zero, last_device;
886         int search_bit, desc_bit;
887         u8  triplet_ret = 0;
888
889         search_bit = 0;
890         rn = last_rn = 0;
891         last_device = 0;
892         last_zero = -1;
893
894         desc_bit = 64;
895
896         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
897                 last_rn = rn;
898                 rn = 0;
899
900                 /*
901                  * Reset bus and all 1-wire device state machines
902                  * so they can respond to our requests.
903                  *
904                  * Return 0 - device(s) present, 1 - no devices present.
905                  */
906                 if (w1_reset_bus(dev)) {
907                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
908                         break;
909                 }
910
911                 /* Start the search */
912                 w1_write_8(dev, search_type);
913                 for (i = 0; i < 64; ++i) {
914                         /* Determine the direction/search bit */
915                         if (i == desc_bit)
916                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
917                         else if (i > desc_bit)
918                                 search_bit = 0;   /* take the 0 path on the next branch */
919                         else
920                                 search_bit = ((last_rn >> i) & 0x1);
921
922                         /** Read two bits and write one bit */
923                         triplet_ret = w1_triplet(dev, search_bit);
924
925                         /* quit if no device responded */
926                         if ( (triplet_ret & 0x03) == 0x03 )
927                                 break;
928
929                         /* If both directions were valid, and we took the 0 path... */
930                         if (triplet_ret == 0)
931                                 last_zero = i;
932
933                         /* extract the direction taken & update the device number */
934                         tmp64 = (triplet_ret >> 2);
935                         rn |= (tmp64 << i);
936
937                         if (kthread_should_stop()) {
938                                 printk(KERN_INFO "Abort w1_search (exiting)\n");
939                                 return;
940                         }
941                 }
942
943                 if ( (triplet_ret & 0x03) != 0x03 ) {
944                         if ( (desc_bit == last_zero) || (last_zero < 0))
945                                 last_device = 1;
946                         desc_bit = last_zero;
947                         cb(dev, rn);
948                 }
949         }
950 }
951
952 void w1_search_process(struct w1_master *dev, u8 search_type)
953 {
954         struct w1_slave *sl, *sln;
955
956         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
957                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
958
959         w1_search_devices(dev, search_type, w1_slave_found);
960
961         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
962                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
963                         w1_slave_detach(sl);
964                 else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
965                         sl->ttl = dev->slave_ttl;
966         }
967
968         if (dev->search_count > 0)
969                 dev->search_count--;
970 }
971
972 int w1_process(void *data)
973 {
974         struct w1_master *dev = (struct w1_master *) data;
975         /* As long as w1_timeout is only set by a module parameter the sleep
976          * time can be calculated in jiffies once.
977          */
978         const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
979
980         while (!kthread_should_stop()) {
981                 if (dev->search_count) {
982                         mutex_lock(&dev->mutex);
983                         w1_search_process(dev, W1_SEARCH);
984                         mutex_unlock(&dev->mutex);
985                 }
986
987                 try_to_freeze();
988                 __set_current_state(TASK_INTERRUPTIBLE);
989
990                 if (kthread_should_stop())
991                         break;
992
993                 /* Only sleep when the search is active. */
994                 if (dev->search_count)
995                         schedule_timeout(jtime);
996                 else
997                         schedule();
998         }
999
1000         atomic_dec(&dev->refcnt);
1001
1002         return 0;
1003 }
1004
1005 static int w1_init(void)
1006 {
1007         int retval;
1008
1009         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
1010
1011         w1_init_netlink();
1012
1013         retval = bus_register(&w1_bus_type);
1014         if (retval) {
1015                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
1016                 goto err_out_exit_init;
1017         }
1018
1019         retval = driver_register(&w1_master_driver);
1020         if (retval) {
1021                 printk(KERN_ERR
1022                         "Failed to register master driver. err=%d.\n",
1023                         retval);
1024                 goto err_out_bus_unregister;
1025         }
1026
1027         retval = driver_register(&w1_slave_driver);
1028         if (retval) {
1029                 printk(KERN_ERR
1030                         "Failed to register master driver. err=%d.\n",
1031                         retval);
1032                 goto err_out_master_unregister;
1033         }
1034
1035         return 0;
1036
1037 #if 0
1038 /* For undoing the slave register if there was a step after it. */
1039 err_out_slave_unregister:
1040         driver_unregister(&w1_slave_driver);
1041 #endif
1042
1043 err_out_master_unregister:
1044         driver_unregister(&w1_master_driver);
1045
1046 err_out_bus_unregister:
1047         bus_unregister(&w1_bus_type);
1048
1049 err_out_exit_init:
1050         return retval;
1051 }
1052
1053 static void w1_fini(void)
1054 {
1055         struct w1_master *dev;
1056
1057         /* Set netlink removal messages and some cleanup */
1058         list_for_each_entry(dev, &w1_masters, w1_master_entry)
1059                 __w1_remove_master_device(dev);
1060
1061         w1_fini_netlink();
1062
1063         driver_unregister(&w1_slave_driver);
1064         driver_unregister(&w1_master_driver);
1065         bus_unregister(&w1_bus_type);
1066 }
1067
1068 module_init(w1_init);
1069 module_exit(w1_fini);