drivers/w1/w1.c

   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33 #include <linux/kthread.h>
  34
  35 #include <asm/atomic.h>
  36
  37 #include "w1.h"
  38 #include "w1_io.h"
  39 #include "w1_log.h"
  40 #include "w1_int.h"
  41 #include "w1_family.h"
  42 #include "w1_netlink.h"
  43
  44 MODULE_LICENSE("GPL");
  45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  47
  48 static int w1_timeout = 10;
  49 static int w1_control_timeout = 1;
  50 int w1_max_slave_count = 10;
  51 int w1_max_slave_ttl = 10;
  52
  53 module_param_named(timeout, w1_timeout, int, 0);
  54 module_param_named(control_timeout, w1_control_timeout, int, 0);
  55 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  56 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  57
  58 DEFINE_SPINLOCK(w1_mlock);
  59 LIST_HEAD(w1_masters);
  60
  61 static struct task_struct *w1_control_thread;
  62
  63 static int w1_master_match(struct device *dev, struct device_driver *drv)
  64 {
  65         return 1;
  66 }
  67
  68 static int w1_master_probe(struct device *dev)
  69 {
  70         return -ENODEV;
  71 }
  72
  73 static void w1_master_release(struct device *dev)
  74 {
  75         struct w1_master *md = dev_to_w1_master(dev);
  76
  77         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  78
  79         dev_fini_netlink(md);
  80         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  81         kfree(md);
  82 }
  83
  84 static void w1_slave_release(struct device *dev)
  85 {
  86         struct w1_slave *sl = dev_to_w1_slave(dev);
  87
  88         dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
  89
  90         while (atomic_read(&sl->refcnt)) {
  91                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
  92                                 sl->name, atomic_read(&sl->refcnt));
  93                 if (msleep_interruptible(1000))
  94                         flush_signals(current);
  95         }
  96
  97         w1_family_put(sl->family);
  98         sl->master->slave_count--;
  99
 100         complete(&sl->released);
 101 }
 102
 103 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 104 {
 105         struct w1_slave *sl = dev_to_w1_slave(dev);
 106
 107         return sprintf(buf, "%s\n", sl->name);
 108 }
 109
 110 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
 111 {
 112         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 113
 114         atomic_inc(&sl->refcnt);
 115         if (off > 8) {
 116                 count = 0;
 117         } else {
 118                 if (off + count > 8)
 119                         count = 8 - off;
 120
 121                 memcpy(buf, (u8 *)&sl->reg_num, count);
 122         }
 123         atomic_dec(&sl->refcnt);
 124
 125         return count;
 126 }
 127
 128 static struct device_attribute w1_slave_attr_name =
 129         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 130
 131 static struct bin_attribute w1_slave_attr_bin_id = {
 132       .attr = {
 133               .name = "id",
 134               .mode = S_IRUGO,
 135               .owner = THIS_MODULE,
 136       },
 137       .size = 8,
 138       .read = w1_slave_read_id,
 139 };
 140
 141 /* Default family */
 142
 143 static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
 144 {
 145         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 146
 147         if (down_interruptible(&sl->master->mutex)) {
 148                 count = 0;
 149                 goto out;
 150         }
 151
 152         if (w1_reset_select_slave(sl)) {
 153                 count = 0;
 154                 goto out_up;
 155         }
 156
 157         w1_write_block(sl->master, buf, count);
 158
 159 out_up:
 160         up(&sl->master->mutex);
 161 out:
 162         return count;
 163 }
 164
 165 static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
 166 {
 167         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 168
 169         if (down_interruptible(&sl->master->mutex)) {
 170                 count = 0;
 171                 goto out;
 172         }
 173
 174         w1_read_block(sl->master, buf, count);
 175
 176         up(&sl->master->mutex);
 177 out:
 178         return count;
 179 }
 180
 181 static struct bin_attribute w1_default_attr = {
 182       .attr = {
 183               .name = "rw",
 184               .mode = S_IRUGO | S_IWUSR,
 185               .owner = THIS_MODULE,
 186       },
 187       .size = PAGE_SIZE,
 188       .read = w1_default_read,
 189       .write = w1_default_write,
 190 };
 191
 192 static int w1_default_add_slave(struct w1_slave *sl)
 193 {
 194         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 195 }
 196
 197 static void w1_default_remove_slave(struct w1_slave *sl)
 198 {
 199         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 200 }
 201
 202 static struct w1_family_ops w1_default_fops = {
 203         .add_slave      = w1_default_add_slave,
 204         .remove_slave   = w1_default_remove_slave,
 205 };
 206
 207 static struct w1_family w1_default_family = {
 208         .fops = &w1_default_fops,
 209 };
 210
 211 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 212
 213 static struct bus_type w1_bus_type = {
 214         .name = "w1",
 215         .match = w1_master_match,
 216         .uevent = w1_uevent,
 217 };
 218
 219 struct device_driver w1_master_driver = {
 220         .name = "w1_master_driver",
 221         .bus = &w1_bus_type,
 222         .probe = w1_master_probe,
 223 };
 224
 225 struct device w1_master_device = {
 226         .parent = NULL,
 227         .bus = &w1_bus_type,
 228         .bus_id = "w1 bus master",
 229         .driver = &w1_master_driver,
 230         .release = &w1_master_release
 231 };
 232
 233 static struct device_driver w1_slave_driver = {
 234         .name = "w1_slave_driver",
 235         .bus = &w1_bus_type,
 236 };
 237
 238 #if 0
 239 struct device w1_slave_device = {
 240         .parent = NULL,
 241         .bus = &w1_bus_type,
 242         .bus_id = "w1 bus slave",
 243         .driver = &w1_slave_driver,
 244         .release = &w1_slave_release
 245 };
 246 #endif  /*  0  */
 247
 248 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 249 {
 250         struct w1_master *md = dev_to_w1_master(dev);
 251         ssize_t count;
 252
 253         if (down_interruptible (&md->mutex))
 254                 return -EBUSY;
 255
 256         count = sprintf(buf, "%s\n", md->name);
 257
 258         up(&md->mutex);
 259
 260         return count;
 261 }
 262
 263 static ssize_t w1_master_attribute_store_search(struct device * dev,
 264                                                 struct device_attribute *attr,
 265                                                 const char * buf, size_t count)
 266 {
 267         struct w1_master *md = dev_to_w1_master(dev);
 268
 269         if (down_interruptible (&md->mutex))
 270                 return -EBUSY;
 271
 272         md->search_count = simple_strtol(buf, NULL, 0);
 273
 274         up(&md->mutex);
 275
 276         return count;
 277 }
 278
 279 static ssize_t w1_master_attribute_show_search(struct device *dev,
 280                                                struct device_attribute *attr,
 281                                                char *buf)
 282 {
 283         struct w1_master *md = dev_to_w1_master(dev);
 284         ssize_t count;
 285
 286         if (down_interruptible (&md->mutex))
 287                 return -EBUSY;
 288
 289         count = sprintf(buf, "%d\n", md->search_count);
 290
 291         up(&md->mutex);
 292
 293         return count;
 294 }
 295
 296 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 297 {
 298         struct w1_master *md = dev_to_w1_master(dev);
 299         ssize_t count;
 300
 301         if (down_interruptible(&md->mutex))
 302                 return -EBUSY;
 303
 304         count = sprintf(buf, "0x%p\n", md->bus_master);
 305
 306         up(&md->mutex);
 307         return count;
 308 }
 309
 310 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 311 {
 312         ssize_t count;
 313         count = sprintf(buf, "%d\n", w1_timeout);
 314         return count;
 315 }
 316
 317 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 318 {
 319         struct w1_master *md = dev_to_w1_master(dev);
 320         ssize_t count;
 321
 322         if (down_interruptible(&md->mutex))
 323                 return -EBUSY;
 324
 325         count = sprintf(buf, "%d\n", md->max_slave_count);
 326
 327         up(&md->mutex);
 328         return count;
 329 }
 330
 331 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 332 {
 333         struct w1_master *md = dev_to_w1_master(dev);
 334         ssize_t count;
 335
 336         if (down_interruptible(&md->mutex))
 337                 return -EBUSY;
 338
 339         count = sprintf(buf, "%lu\n", md->attempts);
 340
 341         up(&md->mutex);
 342         return count;
 343 }
 344
 345 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 346 {
 347         struct w1_master *md = dev_to_w1_master(dev);
 348         ssize_t count;
 349
 350         if (down_interruptible(&md->mutex))
 351                 return -EBUSY;
 352
 353         count = sprintf(buf, "%d\n", md->slave_count);
 354
 355         up(&md->mutex);
 356         return count;
 357 }
 358
 359 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 360 {
 361         struct w1_master *md = dev_to_w1_master(dev);
 362         int c = PAGE_SIZE;
 363
 364         if (down_interruptible(&md->mutex))
 365                 return -EBUSY;
 366
 367         if (md->slave_count == 0)
 368                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 369         else {
 370                 struct list_head *ent, *n;
 371                 struct w1_slave *sl;
 372
 373                 list_for_each_safe(ent, n, &md->slist) {
 374                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 375
 376                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 377                 }
 378         }
 379
 380         up(&md->mutex);
 381
 382         return PAGE_SIZE - c;
 383 }
 384
 385 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 386         struct device_attribute w1_master_attribute_##_name =   \
 387                 __ATTR(w1_master_##_name, _mode,                \
 388                        w1_master_attribute_show_##_name, NULL)
 389
 390 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 391         struct device_attribute w1_master_attribute_##_name =   \
 392                 __ATTR(w1_master_##_name, _mode,                \
 393                        w1_master_attribute_show_##_name,        \
 394                        w1_master_attribute_store_##_name)
 395
 396 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 397 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 398 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 399 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 400 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 401 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 402 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 403 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 404
 405 static struct attribute *w1_master_default_attrs[] = {
 406         &w1_master_attribute_name.attr,
 407         &w1_master_attribute_slaves.attr,
 408         &w1_master_attribute_slave_count.attr,
 409         &w1_master_attribute_max_slave_count.attr,
 410         &w1_master_attribute_attempts.attr,
 411         &w1_master_attribute_timeout.attr,
 412         &w1_master_attribute_pointer.attr,
 413         &w1_master_attribute_search.attr,
 414         NULL
 415 };
 416
 417 static struct attribute_group w1_master_defattr_group = {
 418         .attrs = w1_master_default_attrs,
 419 };
 420
 421 int w1_create_master_attributes(struct w1_master *master)
 422 {
 423         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 424 }
 425
 426 static void w1_destroy_master_attributes(struct w1_master *master)
 427 {
 428         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 429 }
 430
 431 #ifdef CONFIG_HOTPLUG
 432 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 433 {
 434         struct w1_master *md = NULL;
 435         struct w1_slave *sl = NULL;
 436         char *event_owner, *name;
 437         int err, cur_index=0, cur_len=0;
 438
 439         if (dev->driver == &w1_master_driver) {
 440                 md = container_of(dev, struct w1_master, dev);
 441                 event_owner = "master";
 442                 name = md->name;
 443         } else if (dev->driver == &w1_slave_driver) {
 444                 sl = container_of(dev, struct w1_slave, dev);
 445                 event_owner = "slave";
 446                 name = sl->name;
 447         } else {
 448                 dev_dbg(dev, "Unknown event.\n");
 449                 return -EINVAL;
 450         }
 451
 452         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
 453
 454         if (dev->driver != &w1_slave_driver || !sl)
 455                 return 0;
 456
 457         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 458                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
 459         if (err)
 460                 return err;
 461
 462         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 463                         &cur_len, "W1_SLAVE_ID=%024LX",
 464                         (unsigned long long)sl->reg_num.id);
 465         if (err)
 466                 return err;
 467
 468         return 0;
 469 };
 470 #else
 471 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 472 {
 473         return 0;
 474 }
 475 #endif
 476
 477 static int __w1_attach_slave_device(struct w1_slave *sl)
 478 {
 479         int err;
 480
 481         sl->dev.parent = &sl->master->dev;
 482         sl->dev.driver = &w1_slave_driver;
 483         sl->dev.bus = &w1_bus_type;
 484         sl->dev.release = &w1_slave_release;
 485
 486         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 487                  "%02x-%012llx",
 488                  (unsigned int) sl->reg_num.family,
 489                  (unsigned long long) sl->reg_num.id);
 490         snprintf(&sl->name[0], sizeof(sl->name),
 491                  "%02x-%012llx",
 492                  (unsigned int) sl->reg_num.family,
 493                  (unsigned long long) sl->reg_num.id);
 494
 495         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
 496
 497         err = device_register(&sl->dev);
 498         if (err < 0) {
 499                 dev_err(&sl->dev,
 500                         "Device registration [%s] failed. err=%d\n",
 501                         sl->dev.bus_id, err);
 502                 return err;
 503         }
 504
 505         /* Create "name" entry */
 506         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 507         if (err < 0) {
 508                 dev_err(&sl->dev,
 509                         "sysfs file creation for [%s] failed. err=%d\n",
 510                         sl->dev.bus_id, err);
 511                 goto out_unreg;
 512         }
 513
 514         /* Create "id" entry */
 515         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 516         if (err < 0) {
 517                 dev_err(&sl->dev,
 518                         "sysfs file creation for [%s] failed. err=%d\n",
 519                         sl->dev.bus_id, err);
 520                 goto out_rem1;
 521         }
 522
 523         /* if the family driver needs to initialize something... */
 524         if (sl->family->fops && sl->family->fops->add_slave &&
 525             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 526                 dev_err(&sl->dev,
 527                         "sysfs file creation for [%s] failed. err=%d\n",
 528                         sl->dev.bus_id, err);
 529                 goto out_rem2;
 530         }
 531
 532         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 533
 534         return 0;
 535
 536 out_rem2:
 537         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 538 out_rem1:
 539         device_remove_file(&sl->dev, &w1_slave_attr_name);
 540 out_unreg:
 541         device_unregister(&sl->dev);
 542         return err;
 543 }
 544
 545 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 546 {
 547         struct w1_slave *sl;
 548         struct w1_family *f;
 549         int err;
 550         struct w1_netlink_msg msg;
 551
 552         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 553         if (!sl) {
 554                 dev_err(&dev->dev,
 555                          "%s: failed to allocate new slave device.\n",
 556                          __func__);
 557                 return -ENOMEM;
 558         }
 559
 560         memset(sl, 0, sizeof(*sl));
 561
 562         sl->owner = THIS_MODULE;
 563         sl->master = dev;
 564         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 565
 566         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 567         atomic_set(&sl->refcnt, 0);
 568         init_completion(&sl->released);
 569
 570         spin_lock(&w1_flock);
 571         f = w1_family_registered(rn->family);
 572         if (!f) {
 573                 f= &w1_default_family;
 574                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 575                           rn->family, rn->family,
 576                           (unsigned long long)rn->id, rn->crc);
 577         }
 578         __w1_family_get(f);
 579         spin_unlock(&w1_flock);
 580
 581         sl->family = f;
 582
 583
 584         err = __w1_attach_slave_device(sl);
 585         if (err < 0) {
 586                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 587                          sl->name);
 588                 w1_family_put(sl->family);
 589                 kfree(sl);
 590                 return err;
 591         }
 592
 593         sl->ttl = dev->slave_ttl;
 594         dev->slave_count++;
 595
 596         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 597         msg.type = W1_SLAVE_ADD;
 598         w1_netlink_send(dev, &msg);
 599
 600         return 0;
 601 }
 602
 603 static void w1_slave_detach(struct w1_slave *sl)
 604 {
 605         struct w1_netlink_msg msg;
 606
 607         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 608
 609         list_del(&sl->w1_slave_entry);
 610
 611         if (sl->family->fops && sl->family->fops->remove_slave)
 612                 sl->family->fops->remove_slave(sl);
 613
 614         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 615         msg.type = W1_SLAVE_REMOVE;
 616         w1_netlink_send(sl->master, &msg);
 617
 618         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 619         device_remove_file(&sl->dev, &w1_slave_attr_name);
 620         device_unregister(&sl->dev);
 621
 622         wait_for_completion(&sl->released);
 623         kfree(sl);
 624 }
 625
 626 static struct w1_master *w1_search_master(void *data)
 627 {
 628         struct w1_master *dev;
 629         int found = 0;
 630
 631         spin_lock_bh(&w1_mlock);
 632         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 633                 if (dev->bus_master->data == data) {
 634                         found = 1;
 635                         atomic_inc(&dev->refcnt);
 636                         break;
 637                 }
 638         }
 639         spin_unlock_bh(&w1_mlock);
 640
 641         return (found)?dev:NULL;
 642 }
 643
 644 void w1_reconnect_slaves(struct w1_family *f)
 645 {
 646         struct w1_master *dev;
 647
 648         spin_lock_bh(&w1_mlock);
 649         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 650                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 651                                 dev->name, f->fid);
 652                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 653         }
 654         spin_unlock_bh(&w1_mlock);
 655 }
 656
 657 static void w1_slave_found(void *data, u64 rn)
 658 {
 659         int slave_count;
 660         struct w1_slave *sl;
 661         struct list_head *ent;
 662         struct w1_reg_num *tmp;
 663         int family_found = 0;
 664         struct w1_master *dev;
 665         u64 rn_le = cpu_to_le64(rn);
 666
 667         dev = w1_search_master(data);
 668         if (!dev) {
 669                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 670                        "it is impossible.\n", data);
 671                 return;
 672         }
 673
 674         tmp = (struct w1_reg_num *) &rn;
 675
 676         slave_count = 0;
 677         list_for_each(ent, &dev->slist) {
 678
 679                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 680
 681                 if (sl->reg_num.family == tmp->family &&
 682                     sl->reg_num.id == tmp->id &&
 683                     sl->reg_num.crc == tmp->crc) {
 684                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 685                         break;
 686                 } else if (sl->reg_num.family == tmp->family) {
 687                         family_found = 1;
 688                         break;
 689                 }
 690
 691                 slave_count++;
 692         }
 693
 694         if (slave_count == dev->slave_count &&
 695                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 696                 w1_attach_slave_device(dev, tmp);
 697         }
 698
 699         atomic_dec(&dev->refcnt);
 700 }
 701
 702 /**
 703  * Performs a ROM Search & registers any devices found.
 704  * The 1-wire search is a simple binary tree search.
 705  * For each bit of the address, we read two bits and write one bit.
 706  * The bit written will put to sleep all devies that don't match that bit.
 707  * When the two reads differ, the direction choice is obvious.
 708  * When both bits are 0, we must choose a path to take.
 709  * When we can scan all 64 bits without having to choose a path, we are done.
 710  *
 711  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 712  *
 713  * @dev        The master device to search
 714  * @cb         Function to call when a device is found
 715  */
 716 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
 717 {
 718         u64 last_rn, rn, tmp64;
 719         int i, slave_count = 0;
 720         int last_zero, last_device;
 721         int search_bit, desc_bit;
 722         u8  triplet_ret = 0;
 723
 724         search_bit = 0;
 725         rn = last_rn = 0;
 726         last_device = 0;
 727         last_zero = -1;
 728
 729         desc_bit = 64;
 730
 731         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 732                 last_rn = rn;
 733                 rn = 0;
 734
 735                 /*
 736                  * Reset bus and all 1-wire device state machines
 737                  * so they can respond to our requests.
 738                  *
 739                  * Return 0 - device(s) present, 1 - no devices present.
 740                  */
 741                 if (w1_reset_bus(dev)) {
 742                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 743                         break;
 744                 }
 745
 746                 /* Start the search */
 747                 w1_write_8(dev, W1_SEARCH);
 748                 for (i = 0; i < 64; ++i) {
 749                         /* Determine the direction/search bit */
 750                         if (i == desc_bit)
 751                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 752                         else if (i > desc_bit)
 753                                 search_bit = 0;   /* take the 0 path on the next branch */
 754                         else
 755                                 search_bit = ((last_rn >> i) & 0x1);
 756
 757                         /** Read two bits and write one bit */
 758                         triplet_ret = w1_triplet(dev, search_bit);
 759
 760                         /* quit if no device responded */
 761                         if ( (triplet_ret & 0x03) == 0x03 )
 762                                 break;
 763
 764                         /* If both directions were valid, and we took the 0 path... */
 765                         if (triplet_ret == 0)
 766                                 last_zero = i;
 767
 768                         /* extract the direction taken & update the device number */
 769                         tmp64 = (triplet_ret >> 2);
 770                         rn |= (tmp64 << i);
 771                 }
 772
 773                 if ( (triplet_ret & 0x03) != 0x03 ) {
 774                         if ( (desc_bit == last_zero) || (last_zero < 0))
 775                                 last_device = 1;
 776                         desc_bit = last_zero;
 777                         cb(dev->bus_master->data, rn);
 778                 }
 779         }
 780 }
 781
 782 static int w1_control(void *data)
 783 {
 784         struct w1_slave *sl, *sln;
 785         struct w1_master *dev, *n;
 786         int have_to_wait = 0;
 787
 788         while (!kthread_should_stop() || have_to_wait) {
 789                 have_to_wait = 0;
 790
 791                 try_to_freeze();
 792                 msleep_interruptible(w1_control_timeout * 1000);
 793
 794                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 795                         if (!kthread_should_stop() && !dev->flags)
 796                                 continue;
 797                         /*
 798                          * Little race: we can create thread but not set the flag.
 799                          * Get a chance for external process to set flag up.
 800                          */
 801                         if (!dev->initialized) {
 802                                 have_to_wait = 1;
 803                                 continue;
 804                         }
 805
 806                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 807                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 808
 809                                 spin_lock(&w1_mlock);
 810                                 list_del(&dev->w1_master_entry);
 811                                 spin_unlock(&w1_mlock);
 812
 813                                 down(&dev->mutex);
 814                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 815                                         w1_slave_detach(sl);
 816                                 }
 817                                 w1_destroy_master_attributes(dev);
 818                                 up(&dev->mutex);
 819                                 atomic_dec(&dev->refcnt);
 820                                 continue;
 821                         }
 822
 823                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 824                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 825                                 down(&dev->mutex);
 826                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 827                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 828                                                 struct w1_reg_num rn;
 829
 830                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 831                                                 w1_slave_detach(sl);
 832
 833                                                 w1_attach_slave_device(dev, &rn);
 834                                         }
 835                                 }
 836                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 837                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 838                                 up(&dev->mutex);
 839                         }
 840                 }
 841         }
 842
 843         return 0;
 844 }
 845
 846 int w1_process(void *data)
 847 {
 848         struct w1_master *dev = (struct w1_master *) data;
 849         struct w1_slave *sl, *sln;
 850
 851         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 852                 try_to_freeze();
 853                 msleep_interruptible(w1_timeout * 1000);
 854
 855                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 856                         break;
 857
 858                 if (!dev->initialized)
 859                         continue;
 860
 861                 if (dev->search_count == 0)
 862                         continue;
 863
 864                 if (down_interruptible(&dev->mutex))
 865                         continue;
 866
 867                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 868                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 869
 870                 w1_search_devices(dev, w1_slave_found);
 871
 872                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 873                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 874                                 w1_slave_detach(sl);
 875
 876                                 dev->slave_count--;
 877                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 878                                 sl->ttl = dev->slave_ttl;
 879                 }
 880
 881                 if (dev->search_count > 0)
 882                         dev->search_count--;
 883
 884                 up(&dev->mutex);
 885         }
 886
 887         atomic_dec(&dev->refcnt);
 888
 889         return 0;
 890 }
 891
 892 static int w1_init(void)
 893 {
 894         int retval;
 895
 896         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 897
 898         retval = bus_register(&w1_bus_type);
 899         if (retval) {
 900                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 901                 goto err_out_exit_init;
 902         }
 903
 904         retval = driver_register(&w1_master_driver);
 905         if (retval) {
 906                 printk(KERN_ERR
 907                         "Failed to register master driver. err=%d.\n",
 908                         retval);
 909                 goto err_out_bus_unregister;
 910         }
 911
 912         retval = driver_register(&w1_slave_driver);
 913         if (retval) {
 914                 printk(KERN_ERR
 915                         "Failed to register master driver. err=%d.\n",
 916                         retval);
 917                 goto err_out_master_unregister;
 918         }
 919
 920         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 921         if (IS_ERR(w1_control_thread)) {
 922                 retval = PTR_ERR(w1_control_thread);
 923                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 924                         retval);
 925                 goto err_out_slave_unregister;
 926         }
 927
 928         return 0;
 929
 930 err_out_slave_unregister:
 931         driver_unregister(&w1_slave_driver);
 932
 933 err_out_master_unregister:
 934         driver_unregister(&w1_master_driver);
 935
 936 err_out_bus_unregister:
 937         bus_unregister(&w1_bus_type);
 938
 939 err_out_exit_init:
 940         return retval;
 941 }
 942
 943 static void w1_fini(void)
 944 {
 945         struct w1_master *dev;
 946
 947         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 948                 __w1_remove_master_device(dev);
 949
 950         kthread_stop(w1_control_thread);
 951
 952         driver_unregister(&w1_slave_driver);
 953         driver_unregister(&w1_master_driver);
 954         bus_unregister(&w1_bus_type);
 955 }
 956
 957 module_init(w1_init);
 958 module_exit(w1_fini);