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Root/drivers/w1/w1.c

1	/*
2	* w1.c
3	*
4	* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
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 <linux/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 <zbr@ioremap.net>");
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	dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
85
86	while (atomic_read(&sl->refcnt)) {
87	dev_dbg(dev, "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 device *dev,
107	struct device_attribute attr, char buf)
108	{
109	struct w1_slave *sl = dev_to_w1_slave(dev);
110	ssize_t count = sizeof(sl->reg_num);
111
112	memcpy(buf, (u8 *)&sl->reg_num, count);
113	return count;
114	}
115
116	static struct device_attribute w1_slave_attr_name =
117	__ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
118	static struct device_attribute w1_slave_attr_id =
119	__ATTR(id, S_IRUGO, w1_slave_read_id, NULL);
120
121	/* Default family */
122
123	static ssize_t w1_default_write(struct file filp, struct kobject kobj,
124	struct bin_attribute *bin_attr,
125	char *buf, loff_t off, size_t count)
126	{
127	struct w1_slave *sl = kobj_to_w1_slave(kobj);
128
129	mutex_lock(&sl->master->mutex);
130	if (w1_reset_select_slave(sl)) {
131	count = 0;
132	goto out_up;
133	}
134
135	w1_write_block(sl->master, buf, count);
136
137	out_up:
138	mutex_unlock(&sl->master->mutex);
139	return count;
140	}
141
142	static ssize_t w1_default_read(struct file filp, struct kobject kobj,
143	struct bin_attribute *bin_attr,
144	char *buf, loff_t off, size_t count)
145	{
146	struct w1_slave *sl = kobj_to_w1_slave(kobj);
147
148	mutex_lock(&sl->master->mutex);
149	w1_read_block(sl->master, buf, count);
150	mutex_unlock(&sl->master->mutex);
151	return count;
152	}
153
154	static struct bin_attribute w1_default_attr = {
155	.attr = {
156	.name = "rw",
157	.mode = S_IRUGO \| S_IWUSR,
158	},
159	.size = PAGE_SIZE,
160	.read = w1_default_read,
161	.write = w1_default_write,
162	};
163
164	static int w1_default_add_slave(struct w1_slave *sl)
165	{
166	return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
167	}
168
169	static void w1_default_remove_slave(struct w1_slave *sl)
170	{
171	sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
172	}
173
174	static struct w1_family_ops w1_default_fops = {
175	.add_slave = w1_default_add_slave,
176	.remove_slave = w1_default_remove_slave,
177	};
178
179	static struct w1_family w1_default_family = {
180	.fops = &w1_default_fops,
181	};
182
183	static int w1_uevent(struct device dev, struct kobj_uevent_env env);
184
185	static struct bus_type w1_bus_type = {
186	.name = "w1",
187	.match = w1_master_match,
188	.uevent = w1_uevent,
189	};
190
191	struct device_driver w1_master_driver = {
192	.name = "w1_master_driver",
193	.bus = &w1_bus_type,
194	.probe = w1_master_probe,
195	};
196
197	struct device w1_master_device = {
198	.parent = NULL,
199	.bus = &w1_bus_type,
200	.init_name = "w1 bus master",
201	.driver = &w1_master_driver,
202	.release = &w1_master_release
203	};
204
205	static struct device_driver w1_slave_driver = {
206	.name = "w1_slave_driver",
207	.bus = &w1_bus_type,
208	};
209
210	#if 0
211	struct device w1_slave_device = {
212	.parent = NULL,
213	.bus = &w1_bus_type,
214	.init_name = "w1 bus slave",
215	.driver = &w1_slave_driver,
216	.release = &w1_slave_release
217	};
218	#endif /* 0 */
219
220	static ssize_t w1_master_attribute_show_name(struct device dev, struct device_attribute attr, char *buf)
221	{
222	struct w1_master *md = dev_to_w1_master(dev);
223	ssize_t count;
224
225	mutex_lock(&md->mutex);
226	count = sprintf(buf, "%s\n", md->name);
227	mutex_unlock(&md->mutex);
228
229	return count;
230	}
231
232	static ssize_t w1_master_attribute_store_search(struct device * dev,
233	struct device_attribute *attr,
234	const char * buf, size_t count)
235	{
236	long tmp;
237	struct w1_master *md = dev_to_w1_master(dev);
238
239	if (strict_strtol(buf, 0, &tmp) == -EINVAL)
240	return -EINVAL;
241
242	mutex_lock(&md->mutex);
243	md->search_count = tmp;
244	mutex_unlock(&md->mutex);
245	wake_up_process(md->thread);
246
247	return count;
248	}
249
250	static ssize_t w1_master_attribute_show_search(struct device *dev,
251	struct device_attribute *attr,
252	char *buf)
253	{
254	struct w1_master *md = dev_to_w1_master(dev);
255	ssize_t count;
256
257	mutex_lock(&md->mutex);
258	count = sprintf(buf, "%d\n", md->search_count);
259	mutex_unlock(&md->mutex);
260
261	return count;
262	}
263
264	static ssize_t w1_master_attribute_store_pullup(struct device *dev,
265	struct device_attribute *attr,
266	const char *buf, size_t count)
267	{
268	long tmp;
269	struct w1_master *md = dev_to_w1_master(dev);
270
271	if (strict_strtol(buf, 0, &tmp) == -EINVAL)
272	return -EINVAL;
273
274	mutex_lock(&md->mutex);
275	md->enable_pullup = tmp;
276	mutex_unlock(&md->mutex);
277	wake_up_process(md->thread);
278
279	return count;
280	}
281
282	static ssize_t w1_master_attribute_show_pullup(struct device *dev,
283	struct device_attribute *attr,
284	char *buf)
285	{
286	struct w1_master *md = dev_to_w1_master(dev);
287	ssize_t count;
288
289	mutex_lock(&md->mutex);
290	count = sprintf(buf, "%d\n", md->enable_pullup);
291	mutex_unlock(&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	mutex_lock(&md->mutex);
302	count = sprintf(buf, "0x%p\n", md->bus_master);
303	mutex_unlock(&md->mutex);
304	return count;
305	}
306
307	static ssize_t w1_master_attribute_show_timeout(struct device dev, struct device_attribute attr, char *buf)
308	{
309	ssize_t count;
310	count = sprintf(buf, "%d\n", w1_timeout);
311	return count;
312	}
313
314	static ssize_t w1_master_attribute_show_max_slave_count(struct device dev, struct device_attribute attr, char *buf)
315	{
316	struct w1_master *md = dev_to_w1_master(dev);
317	ssize_t count;
318
319	mutex_lock(&md->mutex);
320	count = sprintf(buf, "%d\n", md->max_slave_count);
321	mutex_unlock(&md->mutex);
322	return count;
323	}
324
325	static ssize_t w1_master_attribute_show_attempts(struct device dev, struct device_attribute attr, char *buf)
326	{
327	struct w1_master *md = dev_to_w1_master(dev);
328	ssize_t count;
329
330	mutex_lock(&md->mutex);
331	count = sprintf(buf, "%lu\n", md->attempts);
332	mutex_unlock(&md->mutex);
333	return count;
334	}
335
336	static ssize_t w1_master_attribute_show_slave_count(struct device dev, struct device_attribute attr, char *buf)
337	{
338	struct w1_master *md = dev_to_w1_master(dev);
339	ssize_t count;
340
341	mutex_lock(&md->mutex);
342	count = sprintf(buf, "%d\n", md->slave_count);
343	mutex_unlock(&md->mutex);
344	return count;
345	}
346
347	static ssize_t w1_master_attribute_show_slaves(struct device *dev,
348	struct device_attribute attr, char buf)
349	{
350	struct w1_master *md = dev_to_w1_master(dev);
351	int c = PAGE_SIZE;
352
353	mutex_lock(&md->mutex);
354
355	if (md->slave_count == 0)
356	c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
357	else {
358	struct list_head ent, n;
359	struct w1_slave *sl;
360
361	list_for_each_safe(ent, n, &md->slist) {
362	sl = list_entry(ent, struct w1_slave, w1_slave_entry);
363
364	c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
365	}
366	}
367
368	mutex_unlock(&md->mutex);
369
370	return PAGE_SIZE - c;
371	}
372
373	static ssize_t w1_master_attribute_show_add(struct device *dev,
374	struct device_attribute attr, char buf)
375	{
376	int c = PAGE_SIZE;
377	c -= snprintf(buf+PAGE_SIZE - c, c,
378	"write device id xx-xxxxxxxxxxxx to add slave\n");
379	return PAGE_SIZE - c;
380	}
381
382	static int w1_atoreg_num(struct device dev, const char buf, size_t count,
383	struct w1_reg_num *rn)
384	{
385	unsigned int family;
386	unsigned long long id;
387	int i;
388	u64 rn64_le;
389
390	/* The CRC value isn't read from the user because the sysfs directory
391	* doesn't include it and most messages from the bus search don't
392	* print it either. It would be unreasonable for the user to then
393	* provide it.
394	*/
395	const char *error_msg = "bad slave string format, expecting "
396	"ff-dddddddddddd\n";
397
398	if (buf[2] != '-') {
399	dev_err(dev, "%s", error_msg);
400	return -EINVAL;
401	}
402	i = sscanf(buf, "%02x-%012llx", &family, &id);
403	if (i != 2) {
404	dev_err(dev, "%s", error_msg);
405	return -EINVAL;
406	}
407	rn->family = family;
408	rn->id = id;
409
410	rn64_le = cpu_to_le64((u64 )rn);
411	rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
412
413	#if 0
414	dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
415	rn->family, (unsigned long long)rn->id, rn->crc);
416	#endif
417
418	return 0;
419	}
420
421	/* Searches the slaves in the w1_master and returns a pointer or NULL.
422	* Note: must hold the mutex
423	*/
424	static struct w1_slave w1_slave_search_device(struct w1_master dev,
425	struct w1_reg_num *rn)
426	{
427	struct w1_slave *sl;
428	list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
429	if (sl->reg_num.family == rn->family &&
430	sl->reg_num.id == rn->id &&
431	sl->reg_num.crc == rn->crc) {
432	return sl;
433	}
434	}
435	return NULL;
436	}
437
438	static ssize_t w1_master_attribute_store_add(struct device *dev,
439	struct device_attribute *attr,
440	const char *buf, size_t count)
441	{
442	struct w1_master *md = dev_to_w1_master(dev);
443	struct w1_reg_num rn;
444	struct w1_slave *sl;
445	ssize_t result = count;
446
447	if (w1_atoreg_num(dev, buf, count, &rn))
448	return -EINVAL;
449
450	mutex_lock(&md->mutex);
451	sl = w1_slave_search_device(md, &rn);
452	/* It would be nice to do a targeted search one the one-wire bus
453	* for the new device to see if it is out there or not. But the
454	* current search doesn't support that.
455	*/
456	if (sl) {
457	dev_info(dev, "Device %s already exists\n", sl->name);
458	result = -EINVAL;
459	} else {
460	w1_attach_slave_device(md, &rn);
461	}
462	mutex_unlock(&md->mutex);
463
464	return result;
465	}
466
467	static ssize_t w1_master_attribute_show_remove(struct device *dev,
468	struct device_attribute attr, char buf)
469	{
470	int c = PAGE_SIZE;
471	c -= snprintf(buf+PAGE_SIZE - c, c,
472	"write device id xx-xxxxxxxxxxxx to remove slave\n");
473	return PAGE_SIZE - c;
474	}
475
476	static ssize_t w1_master_attribute_store_remove(struct device *dev,
477	struct device_attribute *attr,
478	const char *buf, size_t count)
479	{
480	struct w1_master *md = dev_to_w1_master(dev);
481	struct w1_reg_num rn;
482	struct w1_slave *sl;
483	ssize_t result = count;
484
485	if (w1_atoreg_num(dev, buf, count, &rn))
486	return -EINVAL;
487
488	mutex_lock(&md->mutex);
489	sl = w1_slave_search_device(md, &rn);
490	if (sl) {
491	w1_slave_detach(sl);
492	} else {
493	dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
494	(unsigned long long)rn.id);
495	result = -EINVAL;
496	}
497	mutex_unlock(&md->mutex);
498
499	return result;
500	}
501
502	#define W1_MASTER_ATTR_RO(_name, _mode) \
503	struct device_attribute w1_master_attribute_##_name = \
504	__ATTR(w1_master_##_name, _mode, \
505	w1_master_attribute_show_##_name, NULL)
506
507	#define W1_MASTER_ATTR_RW(_name, _mode) \
508	struct device_attribute w1_master_attribute_##_name = \
509	__ATTR(w1_master_##_name, _mode, \
510	w1_master_attribute_show_##_name, \
511	w1_master_attribute_store_##_name)
512
513	static W1_MASTER_ATTR_RO(name, S_IRUGO);
514	static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
515	static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
516	static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
517	static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
518	static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
519	static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
520	static W1_MASTER_ATTR_RW(search, S_IRUGO \| S_IWUSR \| S_IWGRP);
521	static W1_MASTER_ATTR_RW(pullup, S_IRUGO \| S_IWUSR \| S_IWGRP);
522	static W1_MASTER_ATTR_RW(add, S_IRUGO \| S_IWUSR \| S_IWGRP);
523	static W1_MASTER_ATTR_RW(remove, S_IRUGO \| S_IWUSR \| S_IWGRP);
524
525	static struct attribute *w1_master_default_attrs[] = {
526	&w1_master_attribute_name.attr,
527	&w1_master_attribute_slaves.attr,
528	&w1_master_attribute_slave_count.attr,
529	&w1_master_attribute_max_slave_count.attr,
530	&w1_master_attribute_attempts.attr,
531	&w1_master_attribute_timeout.attr,
532	&w1_master_attribute_pointer.attr,
533	&w1_master_attribute_search.attr,
534	&w1_master_attribute_pullup.attr,
535	&w1_master_attribute_add.attr,
536	&w1_master_attribute_remove.attr,
537	NULL
538	};
539
540	static struct attribute_group w1_master_defattr_group = {
541	.attrs = w1_master_default_attrs,
542	};
543
544	int w1_create_master_attributes(struct w1_master *master)
545	{
546	return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
547	}
548
549	void w1_destroy_master_attributes(struct w1_master *master)
550	{
551	sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
552	}
553
554	#ifdef CONFIG_HOTPLUG
555	static int w1_uevent(struct device dev, struct kobj_uevent_env env)
556	{
557	struct w1_master *md = NULL;
558	struct w1_slave *sl = NULL;
559	char event_owner, name;
560	int err = 0;
561
562	if (dev->driver == &w1_master_driver) {
563	md = container_of(dev, struct w1_master, dev);
564	event_owner = "master";
565	name = md->name;
566	} else if (dev->driver == &w1_slave_driver) {
567	sl = container_of(dev, struct w1_slave, dev);
568	event_owner = "slave";
569	name = sl->name;
570	} else {
571	dev_dbg(dev, "Unknown event.\n");
572	return -EINVAL;
573	}
574
575	dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
576	event_owner, name, dev_name(dev));
577
578	if (dev->driver != &w1_slave_driver \|\| !sl)
579	goto end;
580
581	err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
582	if (err)
583	goto end;
584
585	err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
586	(unsigned long long)sl->reg_num.id);
587	end:
588	return err;
589	}
590	#else
591	static int w1_uevent(struct device dev, struct kobj_uevent_env env)
592	{
593	return 0;
594	}
595	#endif
596
597	static int __w1_attach_slave_device(struct w1_slave *sl)
598	{
599	int err;
600
601	sl->dev.parent = &sl->master->dev;
602	sl->dev.driver = &w1_slave_driver;
603	sl->dev.bus = &w1_bus_type;
604	sl->dev.release = &w1_slave_release;
605
606	dev_set_name(&sl->dev, "%02x-%012llx",
607	(unsigned int) sl->reg_num.family,
608	(unsigned long long) sl->reg_num.id);
609	snprintf(&sl->name[0], sizeof(sl->name),
610	"%02x-%012llx",
611	(unsigned int) sl->reg_num.family,
612	(unsigned long long) sl->reg_num.id);
613
614	dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
615	dev_name(&sl->dev), sl);
616
617	err = device_register(&sl->dev);
618	if (err < 0) {
619	dev_err(&sl->dev,
620	"Device registration [%s] failed. err=%d\n",
621	dev_name(&sl->dev), err);
622	return err;
623	}
624
625	/* Create "name" entry */
626	err = device_create_file(&sl->dev, &w1_slave_attr_name);
627	if (err < 0) {
628	dev_err(&sl->dev,
629	"sysfs file creation for [%s] failed. err=%d\n",
630	dev_name(&sl->dev), err);
631	goto out_unreg;
632	}
633
634	/* Create "id" entry */
635	err = device_create_file(&sl->dev, &w1_slave_attr_id);
636	if (err < 0) {
637	dev_err(&sl->dev,
638	"sysfs file creation for [%s] failed. err=%d\n",
639	dev_name(&sl->dev), err);
640	goto out_rem1;
641	}
642
643	/* if the family driver needs to initialize something... */
644	if (sl->family->fops && sl->family->fops->add_slave &&
645	((err = sl->family->fops->add_slave(sl)) < 0)) {
646	dev_err(&sl->dev,
647	"sysfs file creation for [%s] failed. err=%d\n",
648	dev_name(&sl->dev), err);
649	goto out_rem2;
650	}
651
652	list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
653
654	return 0;
655
656	out_rem2:
657	device_remove_file(&sl->dev, &w1_slave_attr_id);
658	out_rem1:
659	device_remove_file(&sl->dev, &w1_slave_attr_name);
660	out_unreg:
661	device_unregister(&sl->dev);
662	return err;
663	}
664
665	static int w1_attach_slave_device(struct w1_master dev, struct w1_reg_num rn)
666	{
667	struct w1_slave *sl;
668	struct w1_family *f;
669	int err;
670	struct w1_netlink_msg msg;
671
672	sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
673	if (!sl) {
674	dev_err(&dev->dev,
675	"%s: failed to allocate new slave device.\n",
676	__func__);
677	return -ENOMEM;
678	}
679
680
681	sl->owner = THIS_MODULE;
682	sl->master = dev;
683	set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
684
685	memset(&msg, 0, sizeof(msg));
686	memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
687	atomic_set(&sl->refcnt, 0);
688	init_completion(&sl->released);
689
690	spin_lock(&w1_flock);
691	f = w1_family_registered(rn->family);
692	if (!f) {
693	f= &w1_default_family;
694	dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
695	rn->family, rn->family,
696	(unsigned long long)rn->id, rn->crc);
697	}
698	__w1_family_get(f);
699	spin_unlock(&w1_flock);
700
701	sl->family = f;
702
703
704	err = __w1_attach_slave_device(sl);
705	if (err < 0) {
706	dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
707	sl->name);
708	w1_family_put(sl->family);
709	kfree(sl);
710	return err;
711	}
712
713	sl->ttl = dev->slave_ttl;
714	dev->slave_count++;
715
716	memcpy(msg.id.id, rn, sizeof(msg.id));
717	msg.type = W1_SLAVE_ADD;
718	w1_netlink_send(dev, &msg);
719
720	return 0;
721	}
722
723	void w1_slave_detach(struct w1_slave *sl)
724	{
725	struct w1_netlink_msg msg;
726
727	dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
728
729	list_del(&sl->w1_slave_entry);
730
731	if (sl->family->fops && sl->family->fops->remove_slave)
732	sl->family->fops->remove_slave(sl);
733
734	memset(&msg, 0, sizeof(msg));
735	memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
736	msg.type = W1_SLAVE_REMOVE;
737	w1_netlink_send(sl->master, &msg);
738
739	device_remove_file(&sl->dev, &w1_slave_attr_id);
740	device_remove_file(&sl->dev, &w1_slave_attr_name);
741	device_unregister(&sl->dev);
742
743	wait_for_completion(&sl->released);
744	kfree(sl);
745	}
746
747	struct w1_master *w1_search_master_id(u32 id)
748	{
749	struct w1_master *dev;
750	int found = 0;
751
752	mutex_lock(&w1_mlock);
753	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
754	if (dev->id == id) {
755	found = 1;
756	atomic_inc(&dev->refcnt);
757	break;
758	}
759	}
760	mutex_unlock(&w1_mlock);
761
762	return (found)?dev:NULL;
763	}
764
765	struct w1_slave w1_search_slave(struct w1_reg_num id)
766	{
767	struct w1_master *dev;
768	struct w1_slave *sl = NULL;
769	int found = 0;
770
771	mutex_lock(&w1_mlock);
772	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
773	mutex_lock(&dev->mutex);
774	list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
775	if (sl->reg_num.family == id->family &&
776	sl->reg_num.id == id->id &&
777	sl->reg_num.crc == id->crc) {
778	found = 1;
779	atomic_inc(&dev->refcnt);
780	atomic_inc(&sl->refcnt);
781	break;
782	}
783	}
784	mutex_unlock(&dev->mutex);
785
786	if (found)
787	break;
788	}
789	mutex_unlock(&w1_mlock);
790
791	return (found)?sl:NULL;
792	}
793
794	void w1_reconnect_slaves(struct w1_family *f, int attach)
795	{
796	struct w1_slave sl, sln;
797	struct w1_master *dev;
798
799	mutex_lock(&w1_mlock);
800	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
801	dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
802	"for family %02x.\n", dev->name, f->fid);
803	mutex_lock(&dev->mutex);
804	list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
805	/* If it is a new family, slaves with the default
806	* family driver and are that family will be
807	* connected. If the family is going away, devices
808	* matching that family are reconneced.
809	*/
810	if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
811	&& sl->reg_num.family == f->fid) \|\|
812	(!attach && sl->family->fid == f->fid)) {
813	struct w1_reg_num rn;
814
815	memcpy(&rn, &sl->reg_num, sizeof(rn));
816	w1_slave_detach(sl);
817
818	w1_attach_slave_device(dev, &rn);
819	}
820	}
821	dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
822	"has been finished.\n", dev->name);
823	mutex_unlock(&dev->mutex);
824	}
825	mutex_unlock(&w1_mlock);
826	}
827
828	void w1_slave_found(struct w1_master *dev, u64 rn)
829	{
830	struct w1_slave *sl;
831	struct w1_reg_num *tmp;
832	u64 rn_le = cpu_to_le64(rn);
833
834	atomic_inc(&dev->refcnt);
835
836	tmp = (struct w1_reg_num *) &rn;
837
838	sl = w1_slave_search_device(dev, tmp);
839	if (sl) {
840	set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
841	} else {
842	if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
843	w1_attach_slave_device(dev, tmp);
844	}
845
846	atomic_dec(&dev->refcnt);
847	}
848
849	/**
850	* Performs a ROM Search & registers any devices found.
851	* The 1-wire search is a simple binary tree search.
852	* For each bit of the address, we read two bits and write one bit.
853	* The bit written will put to sleep all devies that don't match that bit.
854	* When the two reads differ, the direction choice is obvious.
855	* When both bits are 0, we must choose a path to take.
856	* When we can scan all 64 bits without having to choose a path, we are done.
857	*
858	* See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
859	*
860	* @dev The master device to search
861	* @cb Function to call when a device is found
862	*/
863	void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
864	{
865	u64 last_rn, rn, tmp64;
866	int i, slave_count = 0;
867	int last_zero, last_device;
868	int search_bit, desc_bit;
869	u8 triplet_ret = 0;
870
871	search_bit = 0;
872	rn = last_rn = 0;
873	last_device = 0;
874	last_zero = -1;
875
876	desc_bit = 64;
877
878	while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
879	last_rn = rn;
880	rn = 0;
881
882	/*
883	* Reset bus and all 1-wire device state machines
884	* so they can respond to our requests.
885	*
886	* Return 0 - device(s) present, 1 - no devices present.
887	*/
888	mutex_lock(&dev->bus_mutex);
889	if (w1_reset_bus(dev)) {
890	mutex_unlock(&dev->bus_mutex);
891	dev_dbg(&dev->dev, "No devices present on the wire.\n");
892	break;
893	}
894
895	/* Do fast search on single slave bus */
896	if (dev->max_slave_count == 1) {
897	int rv;
898	w1_write_8(dev, W1_READ_ROM);
899	rv = w1_read_block(dev, (u8 *)&rn, 8);
900	mutex_unlock(&dev->bus_mutex);
901
902	if (rv == 8 && rn)
903	cb(dev, rn);
904
905	break;
906	}
907
908	/* Start the search */
909	w1_write_8(dev, search_type);
910	for (i = 0; i < 64; ++i) {
911	/* Determine the direction/search bit */
912	if (i == desc_bit)
913	search_bit = 1; /* took the 0 path last time, so take the 1 path */
914	else if (i > desc_bit)
915	search_bit = 0; /* take the 0 path on the next branch */
916	else
917	search_bit = ((last_rn >> i) & 0x1);
918
919	/** Read two bits and write one bit */
920	triplet_ret = w1_triplet(dev, search_bit);
921
922	/* quit if no device responded */
923	if ( (triplet_ret & 0x03) == 0x03 )
924	break;
925
926	/* If both directions were valid, and we took the 0 path... */
927	if (triplet_ret == 0)
928	last_zero = i;
929
930	/* extract the direction taken & update the device number */
931	tmp64 = (triplet_ret >> 2);
932	rn \|= (tmp64 << i);
933
934	if (kthread_should_stop()) {
935	mutex_unlock(&dev->bus_mutex);
936	dev_dbg(&dev->dev, "Abort w1_search\n");
937	return;
938	}
939	}
940	mutex_unlock(&dev->bus_mutex);
941
942	if ( (triplet_ret & 0x03) != 0x03 ) {
943	if ( (desc_bit == last_zero) \|\| (last_zero < 0))
944	last_device = 1;
945	desc_bit = last_zero;
946	cb(dev, rn);
947	}
948	}
949	}
950
951	void w1_search_process_cb(struct w1_master *dev, u8 search_type,
952	w1_slave_found_callback cb)
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, cb);
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	static void w1_search_process(struct w1_master *dev, u8 search_type)
973	{
974	w1_search_process_cb(dev, search_type, w1_slave_found);
975	}
976
977	int w1_process(void *data)
978	{
979	struct w1_master dev = (struct w1_master ) data;
980	/* As long as w1_timeout is only set by a module parameter the sleep
981	* time can be calculated in jiffies once.
982	*/
983	const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
984
985	while (!kthread_should_stop()) {
986	if (dev->search_count) {
987	mutex_lock(&dev->mutex);
988	w1_search_process(dev, W1_SEARCH);
989	mutex_unlock(&dev->mutex);
990	}
991
992	try_to_freeze();
993	__set_current_state(TASK_INTERRUPTIBLE);
994
995	if (kthread_should_stop())
996	break;
997
998	/* Only sleep when the search is active. */
999	if (dev->search_count)
1000	schedule_timeout(jtime);
1001	else
1002	schedule();
1003	}
1004
1005	atomic_dec(&dev->refcnt);
1006
1007	return 0;
1008	}
1009
1010	static int __init w1_init(void)
1011	{
1012	int retval;
1013
1014	printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
1015
1016	w1_init_netlink();
1017
1018	retval = bus_register(&w1_bus_type);
1019	if (retval) {
1020	printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
1021	goto err_out_exit_init;
1022	}
1023
1024	retval = driver_register(&w1_master_driver);
1025	if (retval) {
1026	printk(KERN_ERR
1027	"Failed to register master driver. err=%d.\n",
1028	retval);
1029	goto err_out_bus_unregister;
1030	}
1031
1032	retval = driver_register(&w1_slave_driver);
1033	if (retval) {
1034	printk(KERN_ERR
1035	"Failed to register slave driver. err=%d.\n",
1036	retval);
1037	goto err_out_master_unregister;
1038	}
1039
1040	return 0;
1041
1042	#if 0
1043	/* For undoing the slave register if there was a step after it. */
1044	err_out_slave_unregister:
1045	driver_unregister(&w1_slave_driver);
1046	#endif
1047
1048	err_out_master_unregister:
1049	driver_unregister(&w1_master_driver);
1050
1051	err_out_bus_unregister:
1052	bus_unregister(&w1_bus_type);
1053
1054	err_out_exit_init:
1055	return retval;
1056	}
1057
1058	static void __exit w1_fini(void)
1059	{
1060	struct w1_master *dev;
1061
1062	/* Set netlink removal messages and some cleanup */
1063	list_for_each_entry(dev, &w1_masters, w1_master_entry)
1064	__w1_remove_master_device(dev);
1065
1066	w1_fini_netlink();
1067
1068	driver_unregister(&w1_slave_driver);
1069	driver_unregister(&w1_master_driver);
1070	bus_unregister(&w1_bus_type);
1071	}
1072
1073	module_init(w1_init);
1074	module_exit(w1_fini);
1075

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