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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         if (md->nls && md->nls->sk_socket)
  81                 sock_release(md->nls->sk_socket);
  82         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  83         kfree(md);
  84 }
  85
  86 static void w1_slave_release(struct device *dev)
  87 {
  88         struct w1_slave *sl = dev_to_w1_slave(dev);
  89
  90         dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
  91
  92         while (atomic_read(&sl->refcnt)) {
  93                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
  94                                 sl->name, atomic_read(&sl->refcnt));
  95                 if (msleep_interruptible(1000))
  96                         flush_signals(current);
  97         }
  98
  99         w1_family_put(sl->family);
 100         sl->master->slave_count--;
 101
 102         complete(&sl->released);
 103 }
 104
 105 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 106 {
 107         struct w1_slave *sl = dev_to_w1_slave(dev);
 108
 109         return sprintf(buf, "%s\n", sl->name);
 110 }
 111
 112 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
 113 {
 114         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 115
 116         atomic_inc(&sl->refcnt);
 117         if (off > 8) {
 118                 count = 0;
 119         } else {
 120                 if (off + count > 8)
 121                         count = 8 - off;
 122
 123                 memcpy(buf, (u8 *)&sl->reg_num, count);
 124         }
 125         atomic_dec(&sl->refcnt);
 126
 127         return count;
 128 }
 129
 130 static struct device_attribute w1_slave_attr_name =
 131         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 132
 133 static struct bin_attribute w1_slave_attr_bin_id = {
 134       .attr = {
 135               .name = "id",
 136               .mode = S_IRUGO,
 137               .owner = THIS_MODULE,
 138       },
 139       .size = 8,
 140       .read = w1_slave_read_id,
 141 };
 142
 143 /* Default family */
 144 static struct w1_family w1_default_family;
 145
 146 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 147
 148 static struct bus_type w1_bus_type = {
 149         .name = "w1",
 150         .match = w1_master_match,
 151         .hotplug = w1_hotplug,
 152 };
 153
 154 struct device_driver w1_master_driver = {
 155         .name = "w1_master_driver",
 156         .bus = &w1_bus_type,
 157         .probe = w1_master_probe,
 158 };
 159
 160 struct device w1_master_device = {
 161         .parent = NULL,
 162         .bus = &w1_bus_type,
 163         .bus_id = "w1 bus master",
 164         .driver = &w1_master_driver,
 165         .release = &w1_master_release
 166 };
 167
 168 struct device_driver w1_slave_driver = {
 169         .name = "w1_slave_driver",
 170         .bus = &w1_bus_type,
 171 };
 172
 173 struct device w1_slave_device = {
 174         .parent = NULL,
 175         .bus = &w1_bus_type,
 176         .bus_id = "w1 bus slave",
 177         .driver = &w1_slave_driver,
 178         .release = &w1_slave_release
 179 };
 180
 181 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 182 {
 183         struct w1_master *md = dev_to_w1_master(dev);
 184         ssize_t count;
 185
 186         if (down_interruptible (&md->mutex))
 187                 return -EBUSY;
 188
 189         count = sprintf(buf, "%s\n", md->name);
 190
 191         up(&md->mutex);
 192
 193         return count;
 194 }
 195
 196 static ssize_t w1_master_attribute_store_search(struct device * dev,
 197                                                 struct device_attribute *attr,
 198                                                 const char * buf, size_t count)
 199 {
 200         struct w1_master *md = dev_to_w1_master(dev);
 201
 202         if (down_interruptible (&md->mutex))
 203                 return -EBUSY;
 204
 205         md->search_count = simple_strtol(buf, NULL, 0);
 206
 207         up(&md->mutex);
 208
 209         return count;
 210 }
 211
 212 static ssize_t w1_master_attribute_show_search(struct device *dev,
 213                                                struct device_attribute *attr,
 214                                                char *buf)
 215 {
 216         struct w1_master *md = dev_to_w1_master(dev);
 217         ssize_t count;
 218
 219         if (down_interruptible (&md->mutex))
 220                 return -EBUSY;
 221
 222         count = sprintf(buf, "%d\n", md->search_count);
 223
 224         up(&md->mutex);
 225
 226         return count;
 227 }
 228
 229 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 230 {
 231         struct w1_master *md = dev_to_w1_master(dev);
 232         ssize_t count;
 233
 234         if (down_interruptible(&md->mutex))
 235                 return -EBUSY;
 236
 237         count = sprintf(buf, "0x%p\n", md->bus_master);
 238
 239         up(&md->mutex);
 240         return count;
 241 }
 242
 243 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 244 {
 245         ssize_t count;
 246         count = sprintf(buf, "%d\n", w1_timeout);
 247         return count;
 248 }
 249
 250 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 251 {
 252         struct w1_master *md = dev_to_w1_master(dev);
 253         ssize_t count;
 254
 255         if (down_interruptible(&md->mutex))
 256                 return -EBUSY;
 257
 258         count = sprintf(buf, "%d\n", md->max_slave_count);
 259
 260         up(&md->mutex);
 261         return count;
 262 }
 263
 264 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 265 {
 266         struct w1_master *md = dev_to_w1_master(dev);
 267         ssize_t count;
 268
 269         if (down_interruptible(&md->mutex))
 270                 return -EBUSY;
 271
 272         count = sprintf(buf, "%lu\n", md->attempts);
 273
 274         up(&md->mutex);
 275         return count;
 276 }
 277
 278 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 279 {
 280         struct w1_master *md = dev_to_w1_master(dev);
 281         ssize_t count;
 282
 283         if (down_interruptible(&md->mutex))
 284                 return -EBUSY;
 285
 286         count = sprintf(buf, "%d\n", md->slave_count);
 287
 288         up(&md->mutex);
 289         return count;
 290 }
 291
 292 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 293 {
 294         struct w1_master *md = dev_to_w1_master(dev);
 295         int c = PAGE_SIZE;
 296
 297         if (down_interruptible(&md->mutex))
 298                 return -EBUSY;
 299
 300         if (md->slave_count == 0)
 301                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 302         else {
 303                 struct list_head *ent, *n;
 304                 struct w1_slave *sl;
 305
 306                 list_for_each_safe(ent, n, &md->slist) {
 307                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 308
 309                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 310                 }
 311         }
 312
 313         up(&md->mutex);
 314
 315         return PAGE_SIZE - c;
 316 }
 317
 318 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 319         struct device_attribute w1_master_attribute_##_name =   \
 320                 __ATTR(w1_master_##_name, _mode,                \
 321                        w1_master_attribute_show_##_name, NULL)
 322
 323 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 324         struct device_attribute w1_master_attribute_##_name =   \
 325                 __ATTR(w1_master_##_name, _mode,                \
 326                        w1_master_attribute_show_##_name,        \
 327                        w1_master_attribute_store_##_name)
 328
 329 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 330 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 331 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 332 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 333 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 334 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 335 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 336 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 337
 338 static struct attribute *w1_master_default_attrs[] = {
 339         &w1_master_attribute_name.attr,
 340         &w1_master_attribute_slaves.attr,
 341         &w1_master_attribute_slave_count.attr,
 342         &w1_master_attribute_max_slave_count.attr,
 343         &w1_master_attribute_attempts.attr,
 344         &w1_master_attribute_timeout.attr,
 345         &w1_master_attribute_pointer.attr,
 346         &w1_master_attribute_search.attr,
 347         NULL
 348 };
 349
 350 static struct attribute_group w1_master_defattr_group = {
 351         .attrs = w1_master_default_attrs,
 352 };
 353
 354 int w1_create_master_attributes(struct w1_master *master)
 355 {
 356         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 357 }
 358
 359 void w1_destroy_master_attributes(struct w1_master *master)
 360 {
 361         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 362 }
 363
 364 #ifdef CONFIG_HOTPLUG
 365 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 366 {
 367         struct w1_master *md = NULL;
 368         struct w1_slave *sl = NULL;
 369         char *event_owner, *name;
 370         int err, cur_index=0, cur_len=0;
 371
 372         if (dev->driver == &w1_master_driver) {
 373                 md = container_of(dev, struct w1_master, dev);
 374                 event_owner = "master";
 375                 name = md->name;
 376         } else if (dev->driver == &w1_slave_driver) {
 377                 sl = container_of(dev, struct w1_slave, dev);
 378                 event_owner = "slave";
 379                 name = sl->name;
 380         } else {
 381                 dev_dbg(dev, "Unknown hotplug event.\n");
 382                 return -EINVAL;
 383         }
 384
 385         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
 386
 387         if (dev->driver != &w1_slave_driver || !sl)
 388                 return 0;
 389
 390         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
 391         if (err)
 392                 return err;
 393
 394         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
 395         if (err)
 396                 return err;
 397
 398         return 0;
 399 };
 400 #else
 401 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 402 {
 403         return 0;
 404 }
 405 #endif
 406
 407 static int __w1_attach_slave_device(struct w1_slave *sl)
 408 {
 409         int err;
 410
 411         sl->dev.parent = &sl->master->dev;
 412         sl->dev.driver = &w1_slave_driver;
 413         sl->dev.bus = &w1_bus_type;
 414         sl->dev.release = &w1_slave_release;
 415
 416         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 417                  "%02x-%012llx",
 418                  (unsigned int) sl->reg_num.family,
 419                  (unsigned long long) sl->reg_num.id);
 420         snprintf(&sl->name[0], sizeof(sl->name),
 421                  "%02x-%012llx",
 422                  (unsigned int) sl->reg_num.family,
 423                  (unsigned long long) sl->reg_num.id);
 424
 425         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
 426
 427         err = device_register(&sl->dev);
 428         if (err < 0) {
 429                 dev_err(&sl->dev,
 430                         "Device registration [%s] failed. err=%d\n",
 431                         sl->dev.bus_id, err);
 432                 return err;
 433         }
 434
 435         /* Create "name" entry */
 436         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 437         if (err < 0) {
 438                 dev_err(&sl->dev,
 439                         "sysfs file creation for [%s] failed. err=%d\n",
 440                         sl->dev.bus_id, err);
 441                 goto out_unreg;
 442         }
 443
 444         /* Create "id" entry */
 445         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 446         if (err < 0) {
 447                 dev_err(&sl->dev,
 448                         "sysfs file creation for [%s] failed. err=%d\n",
 449                         sl->dev.bus_id, err);
 450                 goto out_rem1;
 451         }
 452
 453         /* if the family driver needs to initialize something... */
 454         if (sl->family->fops && sl->family->fops->add_slave &&
 455             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 456                 dev_err(&sl->dev,
 457                         "sysfs file creation for [%s] failed. err=%d\n",
 458                         sl->dev.bus_id, err);
 459                 goto out_rem2;
 460         }
 461
 462         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 463
 464         return 0;
 465
 466 out_rem2:
 467         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 468 out_rem1:
 469         device_remove_file(&sl->dev, &w1_slave_attr_name);
 470 out_unreg:
 471         device_unregister(&sl->dev);
 472         return err;
 473 }
 474
 475 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 476 {
 477         struct w1_slave *sl;
 478         struct w1_family *f;
 479         int err;
 480         struct w1_netlink_msg msg;
 481
 482         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 483         if (!sl) {
 484                 dev_err(&dev->dev,
 485                          "%s: failed to allocate new slave device.\n",
 486                          __func__);
 487                 return -ENOMEM;
 488         }
 489
 490         memset(sl, 0, sizeof(*sl));
 491
 492         sl->owner = THIS_MODULE;
 493         sl->master = dev;
 494         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 495
 496         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 497         atomic_set(&sl->refcnt, 0);
 498         init_completion(&sl->released);
 499
 500         spin_lock(&w1_flock);
 501         f = w1_family_registered(rn->family);
 502         if (!f) {
 503                 f= &w1_default_family;
 504                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 505                           rn->family, rn->family,
 506                           (unsigned long long)rn->id, rn->crc);
 507         }
 508         __w1_family_get(f);
 509         spin_unlock(&w1_flock);
 510
 511         sl->family = f;
 512
 513
 514         err = __w1_attach_slave_device(sl);
 515         if (err < 0) {
 516                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 517                          sl->name);
 518                 w1_family_put(sl->family);
 519                 kfree(sl);
 520                 return err;
 521         }
 522
 523         sl->ttl = dev->slave_ttl;
 524         dev->slave_count++;
 525
 526         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 527         msg.type = W1_SLAVE_ADD;
 528         w1_netlink_send(dev, &msg);
 529
 530         return 0;
 531 }
 532
 533 static void w1_slave_detach(struct w1_slave *sl)
 534 {
 535         struct w1_netlink_msg msg;
 536
 537         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 538
 539         list_del(&sl->w1_slave_entry);
 540
 541         if (sl->family->fops && sl->family->fops->remove_slave)
 542                 sl->family->fops->remove_slave(sl);
 543
 544         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 545         msg.type = W1_SLAVE_REMOVE;
 546         w1_netlink_send(sl->master, &msg);
 547
 548         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 549         device_remove_file(&sl->dev, &w1_slave_attr_name);
 550         device_unregister(&sl->dev);
 551
 552         wait_for_completion(&sl->released);
 553         kfree(sl);
 554 }
 555
 556 static struct w1_master *w1_search_master(unsigned long data)
 557 {
 558         struct w1_master *dev;
 559         int found = 0;
 560
 561         spin_lock_bh(&w1_mlock);
 562         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 563                 if (dev->bus_master->data == data) {
 564                         found = 1;
 565                         atomic_inc(&dev->refcnt);
 566                         break;
 567                 }
 568         }
 569         spin_unlock_bh(&w1_mlock);
 570
 571         return (found)?dev:NULL;
 572 }
 573
 574 void w1_reconnect_slaves(struct w1_family *f)
 575 {
 576         struct w1_master *dev;
 577
 578         spin_lock_bh(&w1_mlock);
 579         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 580                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 581                                 dev->name, f->fid);
 582                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 583         }
 584         spin_unlock_bh(&w1_mlock);
 585 }
 586
 587 static void w1_slave_found(unsigned long data, u64 rn)
 588 {
 589         int slave_count;
 590         struct w1_slave *sl;
 591         struct list_head *ent;
 592         struct w1_reg_num *tmp;
 593         int family_found = 0;
 594         struct w1_master *dev;
 595         u64 rn_le = cpu_to_le64(rn);
 596
 597         dev = w1_search_master(data);
 598         if (!dev) {
 599                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 600                                 data);
 601                 return;
 602         }
 603
 604         tmp = (struct w1_reg_num *) &rn;
 605
 606         slave_count = 0;
 607         list_for_each(ent, &dev->slist) {
 608
 609                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 610
 611                 if (sl->reg_num.family == tmp->family &&
 612                     sl->reg_num.id == tmp->id &&
 613                     sl->reg_num.crc == tmp->crc) {
 614                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 615                         break;
 616                 } else if (sl->reg_num.family == tmp->family) {
 617                         family_found = 1;
 618                         break;
 619                 }
 620
 621                 slave_count++;
 622         }
 623
 624         if (slave_count == dev->slave_count &&
 625                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 626                 w1_attach_slave_device(dev, tmp);
 627         }
 628
 629         atomic_dec(&dev->refcnt);
 630 }
 631
 632 /**
 633  * Performs a ROM Search & registers any devices found.
 634  * The 1-wire search is a simple binary tree search.
 635  * For each bit of the address, we read two bits and write one bit.
 636  * The bit written will put to sleep all devies that don't match that bit.
 637  * When the two reads differ, the direction choice is obvious.
 638  * When both bits are 0, we must choose a path to take.
 639  * When we can scan all 64 bits without having to choose a path, we are done.
 640  *
 641  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 642  *
 643  * @dev        The master device to search
 644  * @cb         Function to call when a device is found
 645  */
 646 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
 647 {
 648         u64 last_rn, rn, tmp64;
 649         int i, slave_count = 0;
 650         int last_zero, last_device;
 651         int search_bit, desc_bit;
 652         u8  triplet_ret = 0;
 653
 654         search_bit = 0;
 655         rn = last_rn = 0;
 656         last_device = 0;
 657         last_zero = -1;
 658
 659         desc_bit = 64;
 660
 661         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 662                 last_rn = rn;
 663                 rn = 0;
 664
 665                 /*
 666                  * Reset bus and all 1-wire device state machines
 667                  * so they can respond to our requests.
 668                  *
 669                  * Return 0 - device(s) present, 1 - no devices present.
 670                  */
 671                 if (w1_reset_bus(dev)) {
 672                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 673                         break;
 674                 }
 675
 676                 /* Start the search */
 677                 w1_write_8(dev, W1_SEARCH);
 678                 for (i = 0; i < 64; ++i) {
 679                         /* Determine the direction/search bit */
 680                         if (i == desc_bit)
 681                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 682                         else if (i > desc_bit)
 683                                 search_bit = 0;   /* take the 0 path on the next branch */
 684                         else
 685                                 search_bit = ((last_rn >> i) & 0x1);
 686
 687                         /** Read two bits and write one bit */
 688                         triplet_ret = w1_triplet(dev, search_bit);
 689
 690                         /* quit if no device responded */
 691                         if ( (triplet_ret & 0x03) == 0x03 )
 692                                 break;
 693
 694                         /* If both directions were valid, and we took the 0 path... */
 695                         if (triplet_ret == 0)
 696                                 last_zero = i;
 697
 698                         /* extract the direction taken & update the device number */
 699                         tmp64 = (triplet_ret >> 2);
 700                         rn |= (tmp64 << i);
 701                 }
 702
 703                 if ( (triplet_ret & 0x03) != 0x03 ) {
 704                         if ( (desc_bit == last_zero) || (last_zero < 0))
 705                                 last_device = 1;
 706                         desc_bit = last_zero;
 707                         cb(dev->bus_master->data, rn);
 708                 }
 709         }
 710 }
 711
 712 static int w1_control(void *data)
 713 {
 714         struct w1_slave *sl, *sln;
 715         struct w1_master *dev, *n;
 716         int err, have_to_wait = 0;
 717
 718         daemonize("w1_control");
 719         allow_signal(SIGTERM);
 720
 721         while (!control_needs_exit || have_to_wait) {
 722                 have_to_wait = 0;
 723
 724                 try_to_freeze();
 725                 msleep_interruptible(w1_control_timeout * 1000);
 726
 727                 if (signal_pending(current))
 728                         flush_signals(current);
 729
 730                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 731                         if (!control_needs_exit && !dev->flags)
 732                                 continue;
 733                         /*
 734                          * Little race: we can create thread but not set the flag.
 735                          * Get a chance for external process to set flag up.
 736                          */
 737                         if (!dev->initialized) {
 738                                 have_to_wait = 1;
 739                                 continue;
 740                         }
 741
 742                         if (control_needs_exit) {
 743                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 744
 745                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 746                                 if (err)
 747                                         dev_err(&dev->dev,
 748                                                  "Failed to send signal to w1 kernel thread %d.\n",
 749                                                  dev->kpid);
 750                         }
 751
 752                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 753                                 wait_for_completion(&dev->dev_exited);
 754                                 spin_lock_bh(&w1_mlock);
 755                                 list_del(&dev->w1_master_entry);
 756                                 spin_unlock_bh(&w1_mlock);
 757
 758                                 down(&dev->mutex);
 759                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 760                                         w1_slave_detach(sl);
 761                                 }
 762                                 w1_destroy_master_attributes(dev);
 763                                 up(&dev->mutex);
 764                                 atomic_dec(&dev->refcnt);
 765                                 continue;
 766                         }
 767
 768                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 769                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 770                                 down(&dev->mutex);
 771                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 772                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 773                                                 struct w1_reg_num rn;
 774
 775                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 776                                                 w1_slave_detach(sl);
 777
 778                                                 w1_attach_slave_device(dev, &rn);
 779                                         }
 780                                 }
 781                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 782                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 783                                 up(&dev->mutex);
 784                         }
 785                 }
 786         }
 787
 788         complete_and_exit(&w1_control_complete, 0);
 789 }
 790
 791 int w1_process(void *data)
 792 {
 793         struct w1_master *dev = (struct w1_master *) data;
 794         struct w1_slave *sl, *sln;
 795
 796         daemonize("%s", dev->name);
 797         allow_signal(SIGTERM);
 798
 799         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 800                 try_to_freeze();
 801                 msleep_interruptible(w1_timeout * 1000);
 802
 803                 if (signal_pending(current))
 804                         flush_signals(current);
 805
 806                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 807                         break;
 808
 809                 if (!dev->initialized)
 810                         continue;
 811
 812                 if (dev->search_count == 0)
 813                         continue;
 814
 815                 if (down_interruptible(&dev->mutex))
 816                         continue;
 817
 818                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 819                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 820
 821                 w1_search_devices(dev, w1_slave_found);
 822
 823                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 824                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 825                                 w1_slave_detach(sl);
 826
 827                                 dev->slave_count--;
 828                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 829                                 sl->ttl = dev->slave_ttl;
 830                 }
 831
 832                 if (dev->search_count > 0)
 833                         dev->search_count--;
 834
 835                 up(&dev->mutex);
 836         }
 837
 838         atomic_dec(&dev->refcnt);
 839         complete_and_exit(&dev->dev_exited, 0);
 840
 841         return 0;
 842 }
 843
 844 static int w1_init(void)
 845 {
 846         int retval;
 847
 848         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 849
 850         retval = bus_register(&w1_bus_type);
 851         if (retval) {
 852                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 853                 goto err_out_exit_init;
 854         }
 855
 856         retval = driver_register(&w1_master_driver);
 857         if (retval) {
 858                 printk(KERN_ERR
 859                         "Failed to register master driver. err=%d.\n",
 860                         retval);
 861                 goto err_out_bus_unregister;
 862         }
 863
 864         retval = driver_register(&w1_slave_driver);
 865         if (retval) {
 866                 printk(KERN_ERR
 867                         "Failed to register master driver. err=%d.\n",
 868                         retval);
 869                 goto err_out_master_unregister;
 870         }
 871
 872         control_thread = kernel_thread(&w1_control, NULL, 0);
 873         if (control_thread < 0) {
 874                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 875                         control_thread);
 876                 retval = control_thread;
 877                 goto err_out_slave_unregister;
 878         }
 879
 880         return 0;
 881
 882 err_out_slave_unregister:
 883         driver_unregister(&w1_slave_driver);
 884
 885 err_out_master_unregister:
 886         driver_unregister(&w1_master_driver);
 887
 888 err_out_bus_unregister:
 889         bus_unregister(&w1_bus_type);
 890
 891 err_out_exit_init:
 892         return retval;
 893 }
 894
 895 static void w1_fini(void)
 896 {
 897         struct w1_master *dev;
 898
 899         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 900                 __w1_remove_master_device(dev);
 901
 902         control_needs_exit = 1;
 903         wait_for_completion(&w1_control_complete);
 904
 905         driver_unregister(&w1_slave_driver);
 906         driver_unregister(&w1_master_driver);
 907         bus_unregister(&w1_bus_type);
 908 }
 909
 910 module_init(w1_init);
 911 module_exit(w1_fini);