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   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33
  34 #include <asm/atomic.h>
  35
  36 #include "w1.h"
  37 #include "w1_io.h"
  38 #include "w1_log.h"
  39 #include "w1_int.h"
  40 #include "w1_family.h"
  41 #include "w1_netlink.h"
  42
  43 MODULE_LICENSE("GPL");
  44 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  45 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  46
  47 static int w1_timeout = 10;
  48 static int w1_control_timeout = 1;
  49 int w1_max_slave_count = 10;
  50 int w1_max_slave_ttl = 10;
  51
  52 module_param_named(timeout, w1_timeout, int, 0);
  53 module_param_named(control_timeout, w1_control_timeout, int, 0);
  54 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  55 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  56
  57 DEFINE_SPINLOCK(w1_mlock);
  58 LIST_HEAD(w1_masters);
  59
  60 static pid_t control_thread;
  61 static int control_needs_exit;
  62 static DECLARE_COMPLETION(w1_control_complete);
  63
  64 static int w1_master_match(struct device *dev, struct device_driver *drv)
  65 {
  66         return 1;
  67 }
  68
  69 static int w1_master_probe(struct device *dev)
  70 {
  71         return -ENODEV;
  72 }
  73
  74 static void w1_master_release(struct device *dev)
  75 {
  76         struct w1_master *md = dev_to_w1_master(dev);
  77
  78         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  79
  80         dev_fini_netlink(md);
  81         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  82         kfree(md);
  83 }
  84
  85 static void w1_slave_release(struct device *dev)
  86 {
  87         struct w1_slave *sl = dev_to_w1_slave(dev);
  88
  89         dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
  90
  91         while (atomic_read(&sl->refcnt)) {
  92                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
  93                                 sl->name, atomic_read(&sl->refcnt));
  94                 if (msleep_interruptible(1000))
  95                         flush_signals(current);
  96         }
  97
  98         w1_family_put(sl->family);
  99         sl->master->slave_count--;
 100
 101         complete(&sl->released);
 102 }
 103
 104 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 105 {
 106         struct w1_slave *sl = dev_to_w1_slave(dev);
 107
 108         return sprintf(buf, "%s\n", sl->name);
 109 }
 110
 111 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
 112 {
 113         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 114
 115         atomic_inc(&sl->refcnt);
 116         if (off > 8) {
 117                 count = 0;
 118         } else {
 119                 if (off + count > 8)
 120                         count = 8 - off;
 121
 122                 memcpy(buf, (u8 *)&sl->reg_num, count);
 123         }
 124         atomic_dec(&sl->refcnt);
 125
 126         return count;
 127 }
 128
 129 static struct device_attribute w1_slave_attr_name =
 130         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 131
 132 static struct bin_attribute w1_slave_attr_bin_id = {
 133       .attr = {
 134               .name = "id",
 135               .mode = S_IRUGO,
 136               .owner = THIS_MODULE,
 137       },
 138       .size = 8,
 139       .read = w1_slave_read_id,
 140 };
 141
 142 /* Default family */
 143 static struct w1_family w1_default_family;
 144
 145 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 146
 147 static struct bus_type w1_bus_type = {
 148         .name = "w1",
 149         .match = w1_master_match,
 150         .uevent = w1_uevent,
 151 };
 152
 153 struct device_driver w1_master_driver = {
 154         .name = "w1_master_driver",
 155         .bus = &w1_bus_type,
 156         .probe = w1_master_probe,
 157 };
 158
 159 struct device w1_master_device = {
 160         .parent = NULL,
 161         .bus = &w1_bus_type,
 162         .bus_id = "w1 bus master",
 163         .driver = &w1_master_driver,
 164         .release = &w1_master_release
 165 };
 166
 167 struct device_driver w1_slave_driver = {
 168         .name = "w1_slave_driver",
 169         .bus = &w1_bus_type,
 170 };
 171
 172 struct device w1_slave_device = {
 173         .parent = NULL,
 174         .bus = &w1_bus_type,
 175         .bus_id = "w1 bus slave",
 176         .driver = &w1_slave_driver,
 177         .release = &w1_slave_release
 178 };
 179
 180 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 181 {
 182         struct w1_master *md = dev_to_w1_master(dev);
 183         ssize_t count;
 184
 185         if (down_interruptible (&md->mutex))
 186                 return -EBUSY;
 187
 188         count = sprintf(buf, "%s\n", md->name);
 189
 190         up(&md->mutex);
 191
 192         return count;
 193 }
 194
 195 static ssize_t w1_master_attribute_store_search(struct device * dev,
 196                                                 struct device_attribute *attr,
 197                                                 const char * buf, size_t count)
 198 {
 199         struct w1_master *md = dev_to_w1_master(dev);
 200
 201         if (down_interruptible (&md->mutex))
 202                 return -EBUSY;
 203
 204         md->search_count = simple_strtol(buf, NULL, 0);
 205
 206         up(&md->mutex);
 207
 208         return count;
 209 }
 210
 211 static ssize_t w1_master_attribute_show_search(struct device *dev,
 212                                                struct device_attribute *attr,
 213                                                char *buf)
 214 {
 215         struct w1_master *md = dev_to_w1_master(dev);
 216         ssize_t count;
 217
 218         if (down_interruptible (&md->mutex))
 219                 return -EBUSY;
 220
 221         count = sprintf(buf, "%d\n", md->search_count);
 222
 223         up(&md->mutex);
 224
 225         return count;
 226 }
 227
 228 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 229 {
 230         struct w1_master *md = dev_to_w1_master(dev);
 231         ssize_t count;
 232
 233         if (down_interruptible(&md->mutex))
 234                 return -EBUSY;
 235
 236         count = sprintf(buf, "0x%p\n", md->bus_master);
 237
 238         up(&md->mutex);
 239         return count;
 240 }
 241
 242 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 243 {
 244         ssize_t count;
 245         count = sprintf(buf, "%d\n", w1_timeout);
 246         return count;
 247 }
 248
 249 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 250 {
 251         struct w1_master *md = dev_to_w1_master(dev);
 252         ssize_t count;
 253
 254         if (down_interruptible(&md->mutex))
 255                 return -EBUSY;
 256
 257         count = sprintf(buf, "%d\n", md->max_slave_count);
 258
 259         up(&md->mutex);
 260         return count;
 261 }
 262
 263 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 264 {
 265         struct w1_master *md = dev_to_w1_master(dev);
 266         ssize_t count;
 267
 268         if (down_interruptible(&md->mutex))
 269                 return -EBUSY;
 270
 271         count = sprintf(buf, "%lu\n", md->attempts);
 272
 273         up(&md->mutex);
 274         return count;
 275 }
 276
 277 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 278 {
 279         struct w1_master *md = dev_to_w1_master(dev);
 280         ssize_t count;
 281
 282         if (down_interruptible(&md->mutex))
 283                 return -EBUSY;
 284
 285         count = sprintf(buf, "%d\n", md->slave_count);
 286
 287         up(&md->mutex);
 288         return count;
 289 }
 290
 291 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 292 {
 293         struct w1_master *md = dev_to_w1_master(dev);
 294         int c = PAGE_SIZE;
 295
 296         if (down_interruptible(&md->mutex))
 297                 return -EBUSY;
 298
 299         if (md->slave_count == 0)
 300                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 301         else {
 302                 struct list_head *ent, *n;
 303                 struct w1_slave *sl;
 304
 305                 list_for_each_safe(ent, n, &md->slist) {
 306                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 307
 308                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 309                 }
 310         }
 311
 312         up(&md->mutex);
 313
 314         return PAGE_SIZE - c;
 315 }
 316
 317 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 318         struct device_attribute w1_master_attribute_##_name =   \
 319                 __ATTR(w1_master_##_name, _mode,                \
 320                        w1_master_attribute_show_##_name, NULL)
 321
 322 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 323         struct device_attribute w1_master_attribute_##_name =   \
 324                 __ATTR(w1_master_##_name, _mode,                \
 325                        w1_master_attribute_show_##_name,        \
 326                        w1_master_attribute_store_##_name)
 327
 328 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 329 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 330 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 331 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 332 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 333 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 334 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 335 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 336
 337 static struct attribute *w1_master_default_attrs[] = {
 338         &w1_master_attribute_name.attr,
 339         &w1_master_attribute_slaves.attr,
 340         &w1_master_attribute_slave_count.attr,
 341         &w1_master_attribute_max_slave_count.attr,
 342         &w1_master_attribute_attempts.attr,
 343         &w1_master_attribute_timeout.attr,
 344         &w1_master_attribute_pointer.attr,
 345         &w1_master_attribute_search.attr,
 346         NULL
 347 };
 348
 349 static struct attribute_group w1_master_defattr_group = {
 350         .attrs = w1_master_default_attrs,
 351 };
 352
 353 int w1_create_master_attributes(struct w1_master *master)
 354 {
 355         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 356 }
 357
 358 void w1_destroy_master_attributes(struct w1_master *master)
 359 {
 360         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 361 }
 362
 363 #ifdef CONFIG_HOTPLUG
 364 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 365 {
 366         struct w1_master *md = NULL;
 367         struct w1_slave *sl = NULL;
 368         char *event_owner, *name;
 369         int err, cur_index=0, cur_len=0;
 370
 371         if (dev->driver == &w1_master_driver) {
 372                 md = container_of(dev, struct w1_master, dev);
 373                 event_owner = "master";
 374                 name = md->name;
 375         } else if (dev->driver == &w1_slave_driver) {
 376                 sl = container_of(dev, struct w1_slave, dev);
 377                 event_owner = "slave";
 378                 name = sl->name;
 379         } else {
 380                 dev_dbg(dev, "Unknown event.\n");
 381                 return -EINVAL;
 382         }
 383
 384         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
 385
 386         if (dev->driver != &w1_slave_driver || !sl)
 387                 return 0;
 388
 389         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
 390         if (err)
 391                 return err;
 392
 393         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
 394         if (err)
 395                 return err;
 396
 397         return 0;
 398 };
 399 #else
 400 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 401 {
 402         return 0;
 403 }
 404 #endif
 405
 406 static int __w1_attach_slave_device(struct w1_slave *sl)
 407 {
 408         int err;
 409
 410         sl->dev.parent = &sl->master->dev;
 411         sl->dev.driver = &w1_slave_driver;
 412         sl->dev.bus = &w1_bus_type;
 413         sl->dev.release = &w1_slave_release;
 414
 415         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 416                  "%02x-%012llx",
 417                  (unsigned int) sl->reg_num.family,
 418                  (unsigned long long) sl->reg_num.id);
 419         snprintf(&sl->name[0], sizeof(sl->name),
 420                  "%02x-%012llx",
 421                  (unsigned int) sl->reg_num.family,
 422                  (unsigned long long) sl->reg_num.id);
 423
 424         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
 425
 426         err = device_register(&sl->dev);
 427         if (err < 0) {
 428                 dev_err(&sl->dev,
 429                         "Device registration [%s] failed. err=%d\n",
 430                         sl->dev.bus_id, err);
 431                 return err;
 432         }
 433
 434         /* Create "name" entry */
 435         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 436         if (err < 0) {
 437                 dev_err(&sl->dev,
 438                         "sysfs file creation for [%s] failed. err=%d\n",
 439                         sl->dev.bus_id, err);
 440                 goto out_unreg;
 441         }
 442
 443         /* Create "id" entry */
 444         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 445         if (err < 0) {
 446                 dev_err(&sl->dev,
 447                         "sysfs file creation for [%s] failed. err=%d\n",
 448                         sl->dev.bus_id, err);
 449                 goto out_rem1;
 450         }
 451
 452         /* if the family driver needs to initialize something... */
 453         if (sl->family->fops && sl->family->fops->add_slave &&
 454             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 455                 dev_err(&sl->dev,
 456                         "sysfs file creation for [%s] failed. err=%d\n",
 457                         sl->dev.bus_id, err);
 458                 goto out_rem2;
 459         }
 460
 461         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 462
 463         return 0;
 464
 465 out_rem2:
 466         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 467 out_rem1:
 468         device_remove_file(&sl->dev, &w1_slave_attr_name);
 469 out_unreg:
 470         device_unregister(&sl->dev);
 471         return err;
 472 }
 473
 474 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 475 {
 476         struct w1_slave *sl;
 477         struct w1_family *f;
 478         int err;
 479         struct w1_netlink_msg msg;
 480
 481         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 482         if (!sl) {
 483                 dev_err(&dev->dev,
 484                          "%s: failed to allocate new slave device.\n",
 485                          __func__);
 486                 return -ENOMEM;
 487         }
 488
 489         memset(sl, 0, sizeof(*sl));
 490
 491         sl->owner = THIS_MODULE;
 492         sl->master = dev;
 493         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 494
 495         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 496         atomic_set(&sl->refcnt, 0);
 497         init_completion(&sl->released);
 498
 499         spin_lock(&w1_flock);
 500         f = w1_family_registered(rn->family);
 501         if (!f) {
 502                 f= &w1_default_family;
 503                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 504                           rn->family, rn->family,
 505                           (unsigned long long)rn->id, rn->crc);
 506         }
 507         __w1_family_get(f);
 508         spin_unlock(&w1_flock);
 509
 510         sl->family = f;
 511
 512
 513         err = __w1_attach_slave_device(sl);
 514         if (err < 0) {
 515                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 516                          sl->name);
 517                 w1_family_put(sl->family);
 518                 kfree(sl);
 519                 return err;
 520         }
 521
 522         sl->ttl = dev->slave_ttl;
 523         dev->slave_count++;
 524
 525         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 526         msg.type = W1_SLAVE_ADD;
 527         w1_netlink_send(dev, &msg);
 528
 529         return 0;
 530 }
 531
 532 static void w1_slave_detach(struct w1_slave *sl)
 533 {
 534         struct w1_netlink_msg msg;
 535
 536         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 537
 538         list_del(&sl->w1_slave_entry);
 539
 540         if (sl->family->fops && sl->family->fops->remove_slave)
 541                 sl->family->fops->remove_slave(sl);
 542
 543         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 544         msg.type = W1_SLAVE_REMOVE;
 545         w1_netlink_send(sl->master, &msg);
 546
 547         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 548         device_remove_file(&sl->dev, &w1_slave_attr_name);
 549         device_unregister(&sl->dev);
 550
 551         wait_for_completion(&sl->released);
 552         kfree(sl);
 553 }
 554
 555 static struct w1_master *w1_search_master(unsigned long data)
 556 {
 557         struct w1_master *dev;
 558         int found = 0;
 559
 560         spin_lock_bh(&w1_mlock);
 561         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 562                 if (dev->bus_master->data == data) {
 563                         found = 1;
 564                         atomic_inc(&dev->refcnt);
 565                         break;
 566                 }
 567         }
 568         spin_unlock_bh(&w1_mlock);
 569
 570         return (found)?dev:NULL;
 571 }
 572
 573 void w1_reconnect_slaves(struct w1_family *f)
 574 {
 575         struct w1_master *dev;
 576
 577         spin_lock_bh(&w1_mlock);
 578         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 579                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 580                                 dev->name, f->fid);
 581                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 582         }
 583         spin_unlock_bh(&w1_mlock);
 584 }
 585
 586 static void w1_slave_found(unsigned long data, u64 rn)
 587 {
 588         int slave_count;
 589         struct w1_slave *sl;
 590         struct list_head *ent;
 591         struct w1_reg_num *tmp;
 592         int family_found = 0;
 593         struct w1_master *dev;
 594         u64 rn_le = cpu_to_le64(rn);
 595
 596         dev = w1_search_master(data);
 597         if (!dev) {
 598                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 599                                 data);
 600                 return;
 601         }
 602
 603         tmp = (struct w1_reg_num *) &rn;
 604
 605         slave_count = 0;
 606         list_for_each(ent, &dev->slist) {
 607
 608                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 609
 610                 if (sl->reg_num.family == tmp->family &&
 611                     sl->reg_num.id == tmp->id &&
 612                     sl->reg_num.crc == tmp->crc) {
 613                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 614                         break;
 615                 } else if (sl->reg_num.family == tmp->family) {
 616                         family_found = 1;
 617                         break;
 618                 }
 619
 620                 slave_count++;
 621         }
 622
 623         if (slave_count == dev->slave_count &&
 624                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 625                 w1_attach_slave_device(dev, tmp);
 626         }
 627
 628         atomic_dec(&dev->refcnt);
 629 }
 630
 631 /**
 632  * Performs a ROM Search & registers any devices found.
 633  * The 1-wire search is a simple binary tree search.
 634  * For each bit of the address, we read two bits and write one bit.
 635  * The bit written will put to sleep all devies that don't match that bit.
 636  * When the two reads differ, the direction choice is obvious.
 637  * When both bits are 0, we must choose a path to take.
 638  * When we can scan all 64 bits without having to choose a path, we are done.
 639  *
 640  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 641  *
 642  * @dev        The master device to search
 643  * @cb         Function to call when a device is found
 644  */
 645 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
 646 {
 647         u64 last_rn, rn, tmp64;
 648         int i, slave_count = 0;
 649         int last_zero, last_device;
 650         int search_bit, desc_bit;
 651         u8  triplet_ret = 0;
 652
 653         search_bit = 0;
 654         rn = last_rn = 0;
 655         last_device = 0;
 656         last_zero = -1;
 657
 658         desc_bit = 64;
 659
 660         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 661                 last_rn = rn;
 662                 rn = 0;
 663
 664                 /*
 665                  * Reset bus and all 1-wire device state machines
 666                  * so they can respond to our requests.
 667                  *
 668                  * Return 0 - device(s) present, 1 - no devices present.
 669                  */
 670                 if (w1_reset_bus(dev)) {
 671                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 672                         break;
 673                 }
 674
 675                 /* Start the search */
 676                 w1_write_8(dev, W1_SEARCH);
 677                 for (i = 0; i < 64; ++i) {
 678                         /* Determine the direction/search bit */
 679                         if (i == desc_bit)
 680                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 681                         else if (i > desc_bit)
 682                                 search_bit = 0;   /* take the 0 path on the next branch */
 683                         else
 684                                 search_bit = ((last_rn >> i) & 0x1);
 685
 686                         /** Read two bits and write one bit */
 687                         triplet_ret = w1_triplet(dev, search_bit);
 688
 689                         /* quit if no device responded */
 690                         if ( (triplet_ret & 0x03) == 0x03 )
 691                                 break;
 692
 693                         /* If both directions were valid, and we took the 0 path... */
 694                         if (triplet_ret == 0)
 695                                 last_zero = i;
 696
 697                         /* extract the direction taken & update the device number */
 698                         tmp64 = (triplet_ret >> 2);
 699                         rn |= (tmp64 << i);
 700                 }
 701
 702                 if ( (triplet_ret & 0x03) != 0x03 ) {
 703                         if ( (desc_bit == last_zero) || (last_zero < 0))
 704                                 last_device = 1;
 705                         desc_bit = last_zero;
 706                         cb(dev->bus_master->data, rn);
 707                 }
 708         }
 709 }
 710
 711 static int w1_control(void *data)
 712 {
 713         struct w1_slave *sl, *sln;
 714         struct w1_master *dev, *n;
 715         int err, have_to_wait = 0;
 716
 717         daemonize("w1_control");
 718         allow_signal(SIGTERM);
 719
 720         while (!control_needs_exit || have_to_wait) {
 721                 have_to_wait = 0;
 722
 723                 try_to_freeze();
 724                 msleep_interruptible(w1_control_timeout * 1000);
 725
 726                 if (signal_pending(current))
 727                         flush_signals(current);
 728
 729                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 730                         if (!control_needs_exit && !dev->flags)
 731                                 continue;
 732                         /*
 733                          * Little race: we can create thread but not set the flag.
 734                          * Get a chance for external process to set flag up.
 735                          */
 736                         if (!dev->initialized) {
 737                                 have_to_wait = 1;
 738                                 continue;
 739                         }
 740
 741                         if (control_needs_exit) {
 742                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 743
 744                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 745                                 if (err)
 746                                         dev_err(&dev->dev,
 747                                                  "Failed to send signal to w1 kernel thread %d.\n",
 748                                                  dev->kpid);
 749                         }
 750
 751                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 752                                 wait_for_completion(&dev->dev_exited);
 753                                 spin_lock_bh(&w1_mlock);
 754                                 list_del(&dev->w1_master_entry);
 755                                 spin_unlock_bh(&w1_mlock);
 756
 757                                 down(&dev->mutex);
 758                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 759                                         w1_slave_detach(sl);
 760                                 }
 761                                 w1_destroy_master_attributes(dev);
 762                                 up(&dev->mutex);
 763                                 atomic_dec(&dev->refcnt);
 764                                 continue;
 765                         }
 766
 767                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 768                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 769                                 down(&dev->mutex);
 770                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 771                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 772                                                 struct w1_reg_num rn;
 773
 774                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 775                                                 w1_slave_detach(sl);
 776
 777                                                 w1_attach_slave_device(dev, &rn);
 778                                         }
 779                                 }
 780                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 781                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 782                                 up(&dev->mutex);
 783                         }
 784                 }
 785         }
 786
 787         complete_and_exit(&w1_control_complete, 0);
 788 }
 789
 790 int w1_process(void *data)
 791 {
 792         struct w1_master *dev = (struct w1_master *) data;
 793         struct w1_slave *sl, *sln;
 794
 795         daemonize("%s", dev->name);
 796         allow_signal(SIGTERM);
 797
 798         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 799                 try_to_freeze();
 800                 msleep_interruptible(w1_timeout * 1000);
 801
 802                 if (signal_pending(current))
 803                         flush_signals(current);
 804
 805                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 806                         break;
 807
 808                 if (!dev->initialized)
 809                         continue;
 810
 811                 if (dev->search_count == 0)
 812                         continue;
 813
 814                 if (down_interruptible(&dev->mutex))
 815                         continue;
 816
 817                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 818                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 819
 820                 w1_search_devices(dev, w1_slave_found);
 821
 822                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 823                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 824                                 w1_slave_detach(sl);
 825
 826                                 dev->slave_count--;
 827                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 828                                 sl->ttl = dev->slave_ttl;
 829                 }
 830
 831                 if (dev->search_count > 0)
 832                         dev->search_count--;
 833
 834                 up(&dev->mutex);
 835         }
 836
 837         atomic_dec(&dev->refcnt);
 838         complete_and_exit(&dev->dev_exited, 0);
 839
 840         return 0;
 841 }
 842
 843 static int w1_init(void)
 844 {
 845         int retval;
 846
 847         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 848
 849         retval = bus_register(&w1_bus_type);
 850         if (retval) {
 851                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 852                 goto err_out_exit_init;
 853         }
 854
 855         retval = driver_register(&w1_master_driver);
 856         if (retval) {
 857                 printk(KERN_ERR
 858                         "Failed to register master driver. err=%d.\n",
 859                         retval);
 860                 goto err_out_bus_unregister;
 861         }
 862
 863         retval = driver_register(&w1_slave_driver);
 864         if (retval) {
 865                 printk(KERN_ERR
 866                         "Failed to register master driver. err=%d.\n",
 867                         retval);
 868                 goto err_out_master_unregister;
 869         }
 870
 871         control_thread = kernel_thread(&w1_control, NULL, 0);
 872         if (control_thread < 0) {
 873                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 874                         control_thread);
 875                 retval = control_thread;
 876                 goto err_out_slave_unregister;
 877         }
 878
 879         return 0;
 880
 881 err_out_slave_unregister:
 882         driver_unregister(&w1_slave_driver);
 883
 884 err_out_master_unregister:
 885         driver_unregister(&w1_master_driver);
 886
 887 err_out_bus_unregister:
 888         bus_unregister(&w1_bus_type);
 889
 890 err_out_exit_init:
 891         return retval;
 892 }
 893
 894 static void w1_fini(void)
 895 {
 896         struct w1_master *dev;
 897
 898         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 899                 __w1_remove_master_device(dev);
 900
 901         control_needs_exit = 1;
 902         wait_for_completion(&w1_control_complete);
 903
 904         driver_unregister(&w1_slave_driver);
 905         driver_unregister(&w1_master_driver);
 906         bus_unregister(&w1_bus_type);
 907 }
 908
 909 module_init(w1_init);
 910 module_exit(w1_fini);