[PATCH] w1: Added default generic read/write operations.
[linux-2.6.git] / drivers / w1 / w1.c
1 /*
2  *      w1.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
5  *
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21
22 #include <linux/delay.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/list.h>
27 #include <linux/interrupt.h>
28 #include <linux/spinlock.h>
29 #include <linux/timer.h>
30 #include <linux/device.h>
31 #include <linux/slab.h>
32 #include <linux/sched.h>
33 #include <linux/kthread.h>
34
35 #include <asm/atomic.h>
36
37 #include "w1.h"
38 #include "w1_io.h"
39 #include "w1_log.h"
40 #include "w1_int.h"
41 #include "w1_family.h"
42 #include "w1_netlink.h"
43
44 MODULE_LICENSE("GPL");
45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
47
48 static int w1_timeout = 10;
49 static int w1_control_timeout = 1;
50 int w1_max_slave_count = 10;
51 int w1_max_slave_ttl = 10;
52
53 module_param_named(timeout, w1_timeout, int, 0);
54 module_param_named(control_timeout, w1_control_timeout, int, 0);
55 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
56 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
57
58 DEFINE_SPINLOCK(w1_mlock);
59 LIST_HEAD(w1_masters);
60
61 static struct task_struct *w1_control_thread;
62
63 static int w1_master_match(struct device *dev, struct device_driver *drv)
64 {
65         return 1;
66 }
67
68 static int w1_master_probe(struct device *dev)
69 {
70         return -ENODEV;
71 }
72
73 static void w1_master_release(struct device *dev)
74 {
75         struct w1_master *md = dev_to_w1_master(dev);
76
77         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
78
79         dev_fini_netlink(md);
80         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
81         kfree(md);
82 }
83
84 static void w1_slave_release(struct device *dev)
85 {
86         struct w1_slave *sl = dev_to_w1_slave(dev);
87
88         dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
89
90         while (atomic_read(&sl->refcnt)) {
91                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
92                                 sl->name, atomic_read(&sl->refcnt));
93                 if (msleep_interruptible(1000))
94                         flush_signals(current);
95         }
96
97         w1_family_put(sl->family);
98         sl->master->slave_count--;
99
100         complete(&sl->released);
101 }
102
103 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
104 {
105         struct w1_slave *sl = dev_to_w1_slave(dev);
106
107         return sprintf(buf, "%s\n", sl->name);
108 }
109
110 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
111 {
112         struct w1_slave *sl = kobj_to_w1_slave(kobj);
113
114         atomic_inc(&sl->refcnt);
115         if (off > 8) {
116                 count = 0;
117         } else {
118                 if (off + count > 8)
119                         count = 8 - off;
120
121                 memcpy(buf, (u8 *)&sl->reg_num, count);
122         }
123         atomic_dec(&sl->refcnt);
124
125         return count;
126 }
127
128 static struct device_attribute w1_slave_attr_name =
129         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
130
131 static struct bin_attribute w1_slave_attr_bin_id = {
132       .attr = {
133               .name = "id",
134               .mode = S_IRUGO,
135               .owner = THIS_MODULE,
136       },
137       .size = 8,
138       .read = w1_slave_read_id,
139 };
140
141 /* Default family */
142
143 static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
144 {
145         struct w1_slave *sl = kobj_to_w1_slave(kobj);
146
147         if (down_interruptible(&sl->master->mutex)) {
148                 count = 0;
149                 goto out;
150         }
151
152         if (w1_reset_select_slave(sl)) {
153                 count = 0;
154                 goto out_up;
155         }
156
157         w1_write_block(sl->master, buf, count);
158
159 out_up:
160         up(&sl->master->mutex);
161 out:
162         return count;
163 }
164
165 static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
166 {
167         struct w1_slave *sl = kobj_to_w1_slave(kobj);
168
169         if (down_interruptible(&sl->master->mutex)) {
170                 count = 0;
171                 goto out;
172         }
173
174         w1_read_block(sl->master, buf, count);
175
176         up(&sl->master->mutex);
177 out:
178         return count;
179 }
180
181 static struct bin_attribute w1_default_attr = {
182       .attr = {
183               .name = "rw",
184               .mode = S_IRUGO | S_IWUSR,
185               .owner = THIS_MODULE,
186       },
187       .size = PAGE_SIZE,
188       .read = w1_default_read,
189       .write = w1_default_write,
190 };
191
192 static int w1_default_add_slave(struct w1_slave *sl)
193 {
194         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
195 }
196
197 static void w1_default_remove_slave(struct w1_slave *sl)
198 {
199         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
200 }
201
202 static struct w1_family_ops w1_default_fops = {
203         .add_slave      = w1_default_add_slave,
204         .remove_slave   = w1_default_remove_slave,
205 };
206
207 static struct w1_family w1_default_family = {
208         .fops = &w1_default_fops,
209 };
210
211 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
212
213 static struct bus_type w1_bus_type = {
214         .name = "w1",
215         .match = w1_master_match,
216         .uevent = w1_uevent,
217 };
218
219 struct device_driver w1_master_driver = {
220         .name = "w1_master_driver",
221         .bus = &w1_bus_type,
222         .probe = w1_master_probe,
223 };
224
225 struct device w1_master_device = {
226         .parent = NULL,
227         .bus = &w1_bus_type,
228         .bus_id = "w1 bus master",
229         .driver = &w1_master_driver,
230         .release = &w1_master_release
231 };
232
233 static struct device_driver w1_slave_driver = {
234         .name = "w1_slave_driver",
235         .bus = &w1_bus_type,
236 };
237
238 #if 0
239 struct device w1_slave_device = {
240         .parent = NULL,
241         .bus = &w1_bus_type,
242         .bus_id = "w1 bus slave",
243         .driver = &w1_slave_driver,
244         .release = &w1_slave_release
245 };
246 #endif  /*  0  */
247
248 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
249 {
250         struct w1_master *md = dev_to_w1_master(dev);
251         ssize_t count;
252
253         if (down_interruptible (&md->mutex))
254                 return -EBUSY;
255
256         count = sprintf(buf, "%s\n", md->name);
257
258         up(&md->mutex);
259
260         return count;
261 }
262
263 static ssize_t w1_master_attribute_store_search(struct device * dev,
264                                                 struct device_attribute *attr,
265                                                 const char * buf, size_t count)
266 {
267         struct w1_master *md = dev_to_w1_master(dev);
268
269         if (down_interruptible (&md->mutex))
270                 return -EBUSY;
271
272         md->search_count = simple_strtol(buf, NULL, 0);
273
274         up(&md->mutex);
275
276         return count;
277 }
278
279 static ssize_t w1_master_attribute_show_search(struct device *dev,
280                                                struct device_attribute *attr,
281                                                char *buf)
282 {
283         struct w1_master *md = dev_to_w1_master(dev);
284         ssize_t count;
285
286         if (down_interruptible (&md->mutex))
287                 return -EBUSY;
288
289         count = sprintf(buf, "%d\n", md->search_count);
290
291         up(&md->mutex);
292
293         return count;
294 }
295
296 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
297 {
298         struct w1_master *md = dev_to_w1_master(dev);
299         ssize_t count;
300
301         if (down_interruptible(&md->mutex))
302                 return -EBUSY;
303
304         count = sprintf(buf, "0x%p\n", md->bus_master);
305
306         up(&md->mutex);
307         return count;
308 }
309
310 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
311 {
312         ssize_t count;
313         count = sprintf(buf, "%d\n", w1_timeout);
314         return count;
315 }
316
317 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
318 {
319         struct w1_master *md = dev_to_w1_master(dev);
320         ssize_t count;
321
322         if (down_interruptible(&md->mutex))
323                 return -EBUSY;
324
325         count = sprintf(buf, "%d\n", md->max_slave_count);
326
327         up(&md->mutex);
328         return count;
329 }
330
331 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
332 {
333         struct w1_master *md = dev_to_w1_master(dev);
334         ssize_t count;
335
336         if (down_interruptible(&md->mutex))
337                 return -EBUSY;
338
339         count = sprintf(buf, "%lu\n", md->attempts);
340
341         up(&md->mutex);
342         return count;
343 }
344
345 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
346 {
347         struct w1_master *md = dev_to_w1_master(dev);
348         ssize_t count;
349
350         if (down_interruptible(&md->mutex))
351                 return -EBUSY;
352
353         count = sprintf(buf, "%d\n", md->slave_count);
354
355         up(&md->mutex);
356         return count;
357 }
358
359 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
360 {
361         struct w1_master *md = dev_to_w1_master(dev);
362         int c = PAGE_SIZE;
363
364         if (down_interruptible(&md->mutex))
365                 return -EBUSY;
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         up(&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
405 static struct attribute *w1_master_default_attrs[] = {
406         &w1_master_attribute_name.attr,
407         &w1_master_attribute_slaves.attr,
408         &w1_master_attribute_slave_count.attr,
409         &w1_master_attribute_max_slave_count.attr,
410         &w1_master_attribute_attempts.attr,
411         &w1_master_attribute_timeout.attr,
412         &w1_master_attribute_pointer.attr,
413         &w1_master_attribute_search.attr,
414         NULL
415 };
416
417 static struct attribute_group w1_master_defattr_group = {
418         .attrs = w1_master_default_attrs,
419 };
420
421 int w1_create_master_attributes(struct w1_master *master)
422 {
423         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
424 }
425
426 static void w1_destroy_master_attributes(struct w1_master *master)
427 {
428         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
429 }
430
431 #ifdef CONFIG_HOTPLUG
432 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
433 {
434         struct w1_master *md = NULL;
435         struct w1_slave *sl = NULL;
436         char *event_owner, *name;
437         int err, cur_index=0, cur_len=0;
438
439         if (dev->driver == &w1_master_driver) {
440                 md = container_of(dev, struct w1_master, dev);
441                 event_owner = "master";
442                 name = md->name;
443         } else if (dev->driver == &w1_slave_driver) {
444                 sl = container_of(dev, struct w1_slave, dev);
445                 event_owner = "slave";
446                 name = sl->name;
447         } else {
448                 dev_dbg(dev, "Unknown event.\n");
449                 return -EINVAL;
450         }
451
452         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
453
454         if (dev->driver != &w1_slave_driver || !sl)
455                 return 0;
456
457         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
458                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
459         if (err)
460                 return err;
461
462         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
463                         &cur_len, "W1_SLAVE_ID=%024LX",
464                         (unsigned long long)sl->reg_num.id);
465         if (err)
466                 return err;
467
468         return 0;
469 };
470 #else
471 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
472 {
473         return 0;
474 }
475 #endif
476
477 static int __w1_attach_slave_device(struct w1_slave *sl)
478 {
479         int err;
480
481         sl->dev.parent = &sl->master->dev;
482         sl->dev.driver = &w1_slave_driver;
483         sl->dev.bus = &w1_bus_type;
484         sl->dev.release = &w1_slave_release;
485
486         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
487                  "%02x-%012llx",
488                  (unsigned int) sl->reg_num.family,
489                  (unsigned long long) sl->reg_num.id);
490         snprintf(&sl->name[0], sizeof(sl->name),
491                  "%02x-%012llx",
492                  (unsigned int) sl->reg_num.family,
493                  (unsigned long long) sl->reg_num.id);
494
495         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
496
497         err = device_register(&sl->dev);
498         if (err < 0) {
499                 dev_err(&sl->dev,
500                         "Device registration [%s] failed. err=%d\n",
501                         sl->dev.bus_id, err);
502                 return err;
503         }
504
505         /* Create "name" entry */
506         err = device_create_file(&sl->dev, &w1_slave_attr_name);
507         if (err < 0) {
508                 dev_err(&sl->dev,
509                         "sysfs file creation for [%s] failed. err=%d\n",
510                         sl->dev.bus_id, err);
511                 goto out_unreg;
512         }
513
514         /* Create "id" entry */
515         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
516         if (err < 0) {
517                 dev_err(&sl->dev,
518                         "sysfs file creation for [%s] failed. err=%d\n",
519                         sl->dev.bus_id, err);
520                 goto out_rem1;
521         }
522
523         /* if the family driver needs to initialize something... */
524         if (sl->family->fops && sl->family->fops->add_slave &&
525             ((err = sl->family->fops->add_slave(sl)) < 0)) {
526                 dev_err(&sl->dev,
527                         "sysfs file creation for [%s] failed. err=%d\n",
528                         sl->dev.bus_id, err);
529                 goto out_rem2;
530         }
531
532         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
533
534         return 0;
535
536 out_rem2:
537         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
538 out_rem1:
539         device_remove_file(&sl->dev, &w1_slave_attr_name);
540 out_unreg:
541         device_unregister(&sl->dev);
542         return err;
543 }
544
545 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
546 {
547         struct w1_slave *sl;
548         struct w1_family *f;
549         int err;
550         struct w1_netlink_msg msg;
551
552         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
553         if (!sl) {
554                 dev_err(&dev->dev,
555                          "%s: failed to allocate new slave device.\n",
556                          __func__);
557                 return -ENOMEM;
558         }
559
560         memset(sl, 0, sizeof(*sl));
561
562         sl->owner = THIS_MODULE;
563         sl->master = dev;
564         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
565
566         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
567         atomic_set(&sl->refcnt, 0);
568         init_completion(&sl->released);
569
570         spin_lock(&w1_flock);
571         f = w1_family_registered(rn->family);
572         if (!f) {
573                 f= &w1_default_family;
574                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
575                           rn->family, rn->family,
576                           (unsigned long long)rn->id, rn->crc);
577         }
578         __w1_family_get(f);
579         spin_unlock(&w1_flock);
580
581         sl->family = f;
582
583
584         err = __w1_attach_slave_device(sl);
585         if (err < 0) {
586                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
587                          sl->name);
588                 w1_family_put(sl->family);
589                 kfree(sl);
590                 return err;
591         }
592
593         sl->ttl = dev->slave_ttl;
594         dev->slave_count++;
595
596         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
597         msg.type = W1_SLAVE_ADD;
598         w1_netlink_send(dev, &msg);
599
600         return 0;
601 }
602
603 static void w1_slave_detach(struct w1_slave *sl)
604 {
605         struct w1_netlink_msg msg;
606
607         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
608
609         list_del(&sl->w1_slave_entry);
610
611         if (sl->family->fops && sl->family->fops->remove_slave)
612                 sl->family->fops->remove_slave(sl);
613
614         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
615         msg.type = W1_SLAVE_REMOVE;
616         w1_netlink_send(sl->master, &msg);
617
618         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
619         device_remove_file(&sl->dev, &w1_slave_attr_name);
620         device_unregister(&sl->dev);
621
622         wait_for_completion(&sl->released);
623         kfree(sl);
624 }
625
626 static struct w1_master *w1_search_master(void *data)
627 {
628         struct w1_master *dev;
629         int found = 0;
630
631         spin_lock_bh(&w1_mlock);
632         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
633                 if (dev->bus_master->data == data) {
634                         found = 1;
635                         atomic_inc(&dev->refcnt);
636                         break;
637                 }
638         }
639         spin_unlock_bh(&w1_mlock);
640
641         return (found)?dev:NULL;
642 }
643
644 void w1_reconnect_slaves(struct w1_family *f)
645 {
646         struct w1_master *dev;
647
648         spin_lock_bh(&w1_mlock);
649         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
650                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
651                                 dev->name, f->fid);
652                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
653         }
654         spin_unlock_bh(&w1_mlock);
655 }
656
657 static void w1_slave_found(void *data, u64 rn)
658 {
659         int slave_count;
660         struct w1_slave *sl;
661         struct list_head *ent;
662         struct w1_reg_num *tmp;
663         int family_found = 0;
664         struct w1_master *dev;
665         u64 rn_le = cpu_to_le64(rn);
666
667         dev = w1_search_master(data);
668         if (!dev) {
669                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
670                        "it is impossible.\n", data);
671                 return;
672         }
673
674         tmp = (struct w1_reg_num *) &rn;
675
676         slave_count = 0;
677         list_for_each(ent, &dev->slist) {
678
679                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
680
681                 if (sl->reg_num.family == tmp->family &&
682                     sl->reg_num.id == tmp->id &&
683                     sl->reg_num.crc == tmp->crc) {
684                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
685                         break;
686                 } else if (sl->reg_num.family == tmp->family) {
687                         family_found = 1;
688                         break;
689                 }
690
691                 slave_count++;
692         }
693
694         if (slave_count == dev->slave_count &&
695                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
696                 w1_attach_slave_device(dev, tmp);
697         }
698
699         atomic_dec(&dev->refcnt);
700 }
701
702 /**
703  * Performs a ROM Search & registers any devices found.
704  * The 1-wire search is a simple binary tree search.
705  * For each bit of the address, we read two bits and write one bit.
706  * The bit written will put to sleep all devies that don't match that bit.
707  * When the two reads differ, the direction choice is obvious.
708  * When both bits are 0, we must choose a path to take.
709  * When we can scan all 64 bits without having to choose a path, we are done.
710  *
711  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
712  *
713  * @dev        The master device to search
714  * @cb         Function to call when a device is found
715  */
716 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
717 {
718         u64 last_rn, rn, tmp64;
719         int i, slave_count = 0;
720         int last_zero, last_device;
721         int search_bit, desc_bit;
722         u8  triplet_ret = 0;
723
724         search_bit = 0;
725         rn = last_rn = 0;
726         last_device = 0;
727         last_zero = -1;
728
729         desc_bit = 64;
730
731         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
732                 last_rn = rn;
733                 rn = 0;
734
735                 /*
736                  * Reset bus and all 1-wire device state machines
737                  * so they can respond to our requests.
738                  *
739                  * Return 0 - device(s) present, 1 - no devices present.
740                  */
741                 if (w1_reset_bus(dev)) {
742                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
743                         break;
744                 }
745
746                 /* Start the search */
747                 w1_write_8(dev, W1_SEARCH);
748                 for (i = 0; i < 64; ++i) {
749                         /* Determine the direction/search bit */
750                         if (i == desc_bit)
751                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
752                         else if (i > desc_bit)
753                                 search_bit = 0;   /* take the 0 path on the next branch */
754                         else
755                                 search_bit = ((last_rn >> i) & 0x1);
756
757                         /** Read two bits and write one bit */
758                         triplet_ret = w1_triplet(dev, search_bit);
759
760                         /* quit if no device responded */
761                         if ( (triplet_ret & 0x03) == 0x03 )
762                                 break;
763
764                         /* If both directions were valid, and we took the 0 path... */
765                         if (triplet_ret == 0)
766                                 last_zero = i;
767
768                         /* extract the direction taken & update the device number */
769                         tmp64 = (triplet_ret >> 2);
770                         rn |= (tmp64 << i);
771                 }
772
773                 if ( (triplet_ret & 0x03) != 0x03 ) {
774                         if ( (desc_bit == last_zero) || (last_zero < 0))
775                                 last_device = 1;
776                         desc_bit = last_zero;
777                         cb(dev->bus_master->data, rn);
778                 }
779         }
780 }
781
782 static int w1_control(void *data)
783 {
784         struct w1_slave *sl, *sln;
785         struct w1_master *dev, *n;
786         int have_to_wait = 0;
787
788         while (!kthread_should_stop() || have_to_wait) {
789                 have_to_wait = 0;
790
791                 try_to_freeze();
792                 msleep_interruptible(w1_control_timeout * 1000);
793
794                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
795                         if (!kthread_should_stop() && !dev->flags)
796                                 continue;
797                         /*
798                          * Little race: we can create thread but not set the flag.
799                          * Get a chance for external process to set flag up.
800                          */
801                         if (!dev->initialized) {
802                                 have_to_wait = 1;
803                                 continue;
804                         }
805
806                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
807                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
808
809                                 spin_lock(&w1_mlock);
810                                 list_del(&dev->w1_master_entry);
811                                 spin_unlock(&w1_mlock);
812
813                                 down(&dev->mutex);
814                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
815                                         w1_slave_detach(sl);
816                                 }
817                                 w1_destroy_master_attributes(dev);
818                                 up(&dev->mutex);
819                                 atomic_dec(&dev->refcnt);
820                                 continue;
821                         }
822
823                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
824                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
825                                 down(&dev->mutex);
826                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
827                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
828                                                 struct w1_reg_num rn;
829
830                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
831                                                 w1_slave_detach(sl);
832
833                                                 w1_attach_slave_device(dev, &rn);
834                                         }
835                                 }
836                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
837                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
838                                 up(&dev->mutex);
839                         }
840                 }
841         }
842
843         return 0;
844 }
845
846 int w1_process(void *data)
847 {
848         struct w1_master *dev = (struct w1_master *) data;
849         struct w1_slave *sl, *sln;
850
851         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
852                 try_to_freeze();
853                 msleep_interruptible(w1_timeout * 1000);
854
855                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
856                         break;
857
858                 if (!dev->initialized)
859                         continue;
860
861                 if (dev->search_count == 0)
862                         continue;
863
864                 if (down_interruptible(&dev->mutex))
865                         continue;
866
867                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
868                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
869
870                 w1_search_devices(dev, w1_slave_found);
871
872                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
873                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
874                                 w1_slave_detach(sl);
875
876                                 dev->slave_count--;
877                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
878                                 sl->ttl = dev->slave_ttl;
879                 }
880
881                 if (dev->search_count > 0)
882                         dev->search_count--;
883
884                 up(&dev->mutex);
885         }
886
887         atomic_dec(&dev->refcnt);
888
889         return 0;
890 }
891
892 static int w1_init(void)
893 {
894         int retval;
895
896         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
897
898         retval = bus_register(&w1_bus_type);
899         if (retval) {
900                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
901                 goto err_out_exit_init;
902         }
903
904         retval = driver_register(&w1_master_driver);
905         if (retval) {
906                 printk(KERN_ERR
907                         "Failed to register master driver. err=%d.\n",
908                         retval);
909                 goto err_out_bus_unregister;
910         }
911
912         retval = driver_register(&w1_slave_driver);
913         if (retval) {
914                 printk(KERN_ERR
915                         "Failed to register master driver. err=%d.\n",
916                         retval);
917                 goto err_out_master_unregister;
918         }
919
920         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
921         if (IS_ERR(w1_control_thread)) {
922                 retval = PTR_ERR(w1_control_thread);
923                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
924                         retval);
925                 goto err_out_slave_unregister;
926         }
927
928         return 0;
929
930 err_out_slave_unregister:
931         driver_unregister(&w1_slave_driver);
932
933 err_out_master_unregister:
934         driver_unregister(&w1_master_driver);
935
936 err_out_bus_unregister:
937         bus_unregister(&w1_bus_type);
938
939 err_out_exit_init:
940         return retval;
941 }
942
943 static void w1_fini(void)
944 {
945         struct w1_master *dev;
946
947         list_for_each_entry(dev, &w1_masters, w1_master_entry)
948                 __w1_remove_master_device(dev);
949
950         kthread_stop(w1_control_thread);
951
952         driver_unregister(&w1_slave_driver);
953         driver_unregister(&w1_master_driver);
954         bus_unregister(&w1_bus_type);
955 }
956
957 module_init(w1_init);
958 module_exit(w1_fini);