drivers/w1/w1.c

   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33
  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         dev_info(&dev->dev, "Finished %s for sl=%p.\n", __func__, sl);
 531
 532         return 0;
 533 }
 534
 535 static void w1_slave_detach(struct w1_slave *sl)
 536 {
 537         struct w1_netlink_msg msg;
 538
 539         dev_info(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 540
 541         list_del(&sl->w1_slave_entry);
 542
 543         if (sl->family->fops && sl->family->fops->remove_slave)
 544                 sl->family->fops->remove_slave(sl);
 545
 546         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 547         msg.type = W1_SLAVE_REMOVE;
 548         w1_netlink_send(sl->master, &msg);
 549
 550         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 551         device_remove_file(&sl->dev, &w1_slave_attr_name);
 552         device_unregister(&sl->dev);
 553
 554         wait_for_completion(&sl->released);
 555         kfree(sl);
 556 }
 557
 558 static struct w1_master *w1_search_master(unsigned long data)
 559 {
 560         struct w1_master *dev;
 561         int found = 0;
 562
 563         spin_lock_bh(&w1_mlock);
 564         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 565                 if (dev->bus_master->data == data) {
 566                         found = 1;
 567                         atomic_inc(&dev->refcnt);
 568                         break;
 569                 }
 570         }
 571         spin_unlock_bh(&w1_mlock);
 572
 573         return (found)?dev:NULL;
 574 }
 575
 576 void w1_reconnect_slaves(struct w1_family *f)
 577 {
 578         struct w1_master *dev;
 579
 580         spin_lock_bh(&w1_mlock);
 581         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 582                 dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 583                                 dev->name, f->fid);
 584                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 585         }
 586         spin_unlock_bh(&w1_mlock);
 587 }
 588
 589 static void w1_slave_found(unsigned long data, u64 rn)
 590 {
 591         int slave_count;
 592         struct w1_slave *sl;
 593         struct list_head *ent;
 594         struct w1_reg_num *tmp;
 595         int family_found = 0;
 596         struct w1_master *dev;
 597         u64 rn_le = cpu_to_le64(rn);
 598
 599         dev = w1_search_master(data);
 600         if (!dev) {
 601                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 602                                 data);
 603                 return;
 604         }
 605
 606         tmp = (struct w1_reg_num *) &rn;
 607
 608         slave_count = 0;
 609         list_for_each(ent, &dev->slist) {
 610
 611                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 612
 613                 if (sl->reg_num.family == tmp->family &&
 614                     sl->reg_num.id == tmp->id &&
 615                     sl->reg_num.crc == tmp->crc) {
 616                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 617                         break;
 618                 } else if (sl->reg_num.family == tmp->family) {
 619                         family_found = 1;
 620                         break;
 621                 }
 622
 623                 slave_count++;
 624         }
 625
 626         if (slave_count == dev->slave_count &&
 627                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 628                 w1_attach_slave_device(dev, tmp);
 629         }
 630
 631         atomic_dec(&dev->refcnt);
 632 }
 633
 634 /**
 635  * Performs a ROM Search & registers any devices found.
 636  * The 1-wire search is a simple binary tree search.
 637  * For each bit of the address, we read two bits and write one bit.
 638  * The bit written will put to sleep all devies that don't match that bit.
 639  * When the two reads differ, the direction choice is obvious.
 640  * When both bits are 0, we must choose a path to take.
 641  * When we can scan all 64 bits without having to choose a path, we are done.
 642  *
 643  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 644  *
 645  * @dev        The master device to search
 646  * @cb         Function to call when a device is found
 647  */
 648 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
 649 {
 650         u64 last_rn, rn, tmp64;
 651         int i, slave_count = 0;
 652         int last_zero, last_device;
 653         int search_bit, desc_bit;
 654         u8  triplet_ret = 0;
 655
 656         search_bit = 0;
 657         rn = last_rn = 0;
 658         last_device = 0;
 659         last_zero = -1;
 660
 661         desc_bit = 64;
 662
 663         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 664                 last_rn = rn;
 665                 rn = 0;
 666
 667                 /*
 668                  * Reset bus and all 1-wire device state machines
 669                  * so they can respond to our requests.
 670                  *
 671                  * Return 0 - device(s) present, 1 - no devices present.
 672                  */
 673                 if (w1_reset_bus(dev)) {
 674                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 675                         break;
 676                 }
 677
 678                 /* Start the search */
 679                 w1_write_8(dev, W1_SEARCH);
 680                 for (i = 0; i < 64; ++i) {
 681                         /* Determine the direction/search bit */
 682                         if (i == desc_bit)
 683                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 684                         else if (i > desc_bit)
 685                                 search_bit = 0;   /* take the 0 path on the next branch */
 686                         else
 687                                 search_bit = ((last_rn >> i) & 0x1);
 688
 689                         /** Read two bits and write one bit */
 690                         triplet_ret = w1_triplet(dev, search_bit);
 691
 692                         /* quit if no device responded */
 693                         if ( (triplet_ret & 0x03) == 0x03 )
 694                                 break;
 695
 696                         /* If both directions were valid, and we took the 0 path... */
 697                         if (triplet_ret == 0)
 698                                 last_zero = i;
 699
 700                         /* extract the direction taken & update the device number */
 701                         tmp64 = (triplet_ret >> 2);
 702                         rn |= (tmp64 << i);
 703                 }
 704
 705                 if ( (triplet_ret & 0x03) != 0x03 ) {
 706                         if ( (desc_bit == last_zero) || (last_zero < 0))
 707                                 last_device = 1;
 708                         desc_bit = last_zero;
 709                         cb(dev->bus_master->data, rn);
 710                 }
 711         }
 712 }
 713
 714 static int w1_control(void *data)
 715 {
 716         struct w1_slave *sl, *sln;
 717         struct w1_master *dev, *n;
 718         int err, have_to_wait = 0;
 719
 720         daemonize("w1_control");
 721         allow_signal(SIGTERM);
 722
 723         while (!control_needs_exit || have_to_wait) {
 724                 have_to_wait = 0;
 725
 726                 try_to_freeze();
 727                 msleep_interruptible(w1_control_timeout * 1000);
 728
 729                 if (signal_pending(current))
 730                         flush_signals(current);
 731
 732                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 733                         if (!control_needs_exit && !dev->flags)
 734                                 continue;
 735                         /*
 736                          * Little race: we can create thread but not set the flag.
 737                          * Get a chance for external process to set flag up.
 738                          */
 739                         if (!dev->initialized) {
 740                                 have_to_wait = 1;
 741                                 continue;
 742                         }
 743
 744                         if (control_needs_exit) {
 745                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 746
 747                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 748                                 if (err)
 749                                         dev_err(&dev->dev,
 750                                                  "Failed to send signal to w1 kernel thread %d.\n",
 751                                                  dev->kpid);
 752                         }
 753
 754                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 755                                 wait_for_completion(&dev->dev_exited);
 756                                 spin_lock_bh(&w1_mlock);
 757                                 list_del(&dev->w1_master_entry);
 758                                 spin_unlock_bh(&w1_mlock);
 759
 760                                 down(&dev->mutex);
 761                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 762                                         w1_slave_detach(sl);
 763                                 }
 764                                 w1_destroy_master_attributes(dev);
 765                                 up(&dev->mutex);
 766                                 atomic_dec(&dev->refcnt);
 767                                 continue;
 768                         }
 769
 770                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 771                                 dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 772                                 down(&dev->mutex);
 773                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 774                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 775                                                 struct w1_reg_num rn;
 776
 777                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 778                                                 w1_slave_detach(sl);
 779
 780                                                 w1_attach_slave_device(dev, &rn);
 781                                         }
 782                                 }
 783                                 dev_info(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 784                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 785                                 up(&dev->mutex);
 786                         }
 787                 }
 788         }
 789
 790         complete_and_exit(&w1_control_complete, 0);
 791 }
 792
 793 int w1_process(void *data)
 794 {
 795         struct w1_master *dev = (struct w1_master *) data;
 796         struct w1_slave *sl, *sln;
 797
 798         daemonize("%s", dev->name);
 799         allow_signal(SIGTERM);
 800
 801         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 802                 try_to_freeze();
 803                 msleep_interruptible(w1_timeout * 1000);
 804
 805                 if (signal_pending(current))
 806                         flush_signals(current);
 807
 808                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 809                         break;
 810
 811                 if (!dev->initialized)
 812                         continue;
 813
 814                 if (dev->search_count == 0)
 815                         continue;
 816
 817                 if (down_interruptible(&dev->mutex))
 818                         continue;
 819
 820                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 821                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 822
 823                 w1_search_devices(dev, w1_slave_found);
 824
 825                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 826                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 827                                 w1_slave_detach(sl);
 828
 829                                 dev->slave_count--;
 830                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 831                                 sl->ttl = dev->slave_ttl;
 832                 }
 833
 834                 if (dev->search_count > 0)
 835                         dev->search_count--;
 836
 837                 up(&dev->mutex);
 838         }
 839
 840         atomic_dec(&dev->refcnt);
 841         complete_and_exit(&dev->dev_exited, 0);
 842
 843         return 0;
 844 }
 845
 846 static int w1_init(void)
 847 {
 848         int retval;
 849
 850         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 851
 852         retval = bus_register(&w1_bus_type);
 853         if (retval) {
 854                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 855                 goto err_out_exit_init;
 856         }
 857
 858         retval = driver_register(&w1_master_driver);
 859         if (retval) {
 860                 printk(KERN_ERR
 861                         "Failed to register master driver. err=%d.\n",
 862                         retval);
 863                 goto err_out_bus_unregister;
 864         }
 865
 866         retval = driver_register(&w1_slave_driver);
 867         if (retval) {
 868                 printk(KERN_ERR
 869                         "Failed to register master driver. err=%d.\n",
 870                         retval);
 871                 goto err_out_master_unregister;
 872         }
 873
 874         control_thread = kernel_thread(&w1_control, NULL, 0);
 875         if (control_thread < 0) {
 876                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 877                         control_thread);
 878                 retval = control_thread;
 879                 goto err_out_slave_unregister;
 880         }
 881
 882         return 0;
 883
 884 err_out_slave_unregister:
 885         driver_unregister(&w1_slave_driver);
 886
 887 err_out_master_unregister:
 888         driver_unregister(&w1_master_driver);
 889
 890 err_out_bus_unregister:
 891         bus_unregister(&w1_bus_type);
 892
 893 err_out_exit_init:
 894         return retval;
 895 }
 896
 897 static void w1_fini(void)
 898 {
 899         struct w1_master *dev;
 900
 901         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 902                 __w1_remove_master_device(dev);
 903
 904         control_needs_exit = 1;
 905         wait_for_completion(&w1_control_complete);
 906
 907         driver_unregister(&w1_slave_driver);
 908         driver_unregister(&w1_master_driver);
 909         bus_unregister(&w1_bus_type);
 910 }
 911
 912 module_init(w1_init);
 913 module_exit(w1_fini);