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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 #include <linux/kthread.h>
  34 #include <linux/freezer.h>
  35
  36 #include <asm/atomic.h>
  37
  38 #include "w1.h"
  39 #include "w1_log.h"
  40 #include "w1_int.h"
  41 #include "w1_family.h"
  42 #include "w1_netlink.h"
  43
  44 MODULE_LICENSE("GPL");
  45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  47
  48 static int w1_timeout = 10;
  49 int w1_max_slave_count = 10;
  50 int w1_max_slave_ttl = 10;
  51
  52 module_param_named(timeout, w1_timeout, int, 0);
  53 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  54 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  55
  56 DEFINE_MUTEX(w1_mlock);
  57 LIST_HEAD(w1_masters);
  58
  59 static int w1_master_match(struct device *dev, struct device_driver *drv)
  60 {
  61         return 1;
  62 }
  63
  64 static int w1_master_probe(struct device *dev)
  65 {
  66         return -ENODEV;
  67 }
  68
  69 static void w1_master_release(struct device *dev)
  70 {
  71         struct w1_master *md = dev_to_w1_master(dev);
  72
  73         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  74         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  75         kfree(md);
  76 }
  77
  78 static void w1_slave_release(struct device *dev)
  79 {
  80         struct w1_slave *sl = dev_to_w1_slave(dev);
  81
  82         printk("%s: Releasing %s.\n", __func__, sl->name);
  83
  84         while (atomic_read(&sl->refcnt)) {
  85                 printk("Waiting for %s to become free: refcnt=%d.\n",
  86                                 sl->name, atomic_read(&sl->refcnt));
  87                 if (msleep_interruptible(1000))
  88                         flush_signals(current);
  89         }
  90
  91         w1_family_put(sl->family);
  92         sl->master->slave_count--;
  93
  94         complete(&sl->released);
  95 }
  96
  97 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
  98 {
  99         struct w1_slave *sl = dev_to_w1_slave(dev);
 100
 101         return sprintf(buf, "%s\n", sl->name);
 102 }
 103
 104 static ssize_t w1_slave_read_id(struct kobject *kobj,
 105                                 struct bin_attribute *bin_attr,
 106                                 char *buf, loff_t off, size_t count)
 107 {
 108         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 109
 110         if (off > 8) {
 111                 count = 0;
 112         } else {
 113                 if (off + count > 8)
 114                         count = 8 - off;
 115
 116                 memcpy(buf, (u8 *)&sl->reg_num, count);
 117         }
 118
 119         return count;
 120 }
 121
 122 static struct device_attribute w1_slave_attr_name =
 123         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 124
 125 static struct bin_attribute w1_slave_attr_bin_id = {
 126       .attr = {
 127               .name = "id",
 128               .mode = S_IRUGO,
 129       },
 130       .size = 8,
 131       .read = w1_slave_read_id,
 132 };
 133
 134 /* Default family */
 135
 136 static ssize_t w1_default_write(struct kobject *kobj,
 137                                 struct bin_attribute *bin_attr,
 138                                 char *buf, loff_t off, size_t count)
 139 {
 140         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 141
 142         mutex_lock(&sl->master->mutex);
 143         if (w1_reset_select_slave(sl)) {
 144                 count = 0;
 145                 goto out_up;
 146         }
 147
 148         w1_write_block(sl->master, buf, count);
 149
 150 out_up:
 151         mutex_unlock(&sl->master->mutex);
 152         return count;
 153 }
 154
 155 static ssize_t w1_default_read(struct kobject *kobj,
 156                                struct bin_attribute *bin_attr,
 157                                char *buf, loff_t off, size_t count)
 158 {
 159         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 160
 161         mutex_lock(&sl->master->mutex);
 162         w1_read_block(sl->master, buf, count);
 163         mutex_unlock(&sl->master->mutex);
 164         return count;
 165 }
 166
 167 static struct bin_attribute w1_default_attr = {
 168       .attr = {
 169               .name = "rw",
 170               .mode = S_IRUGO | S_IWUSR,
 171       },
 172       .size = PAGE_SIZE,
 173       .read = w1_default_read,
 174       .write = w1_default_write,
 175 };
 176
 177 static int w1_default_add_slave(struct w1_slave *sl)
 178 {
 179         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 180 }
 181
 182 static void w1_default_remove_slave(struct w1_slave *sl)
 183 {
 184         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 185 }
 186
 187 static struct w1_family_ops w1_default_fops = {
 188         .add_slave      = w1_default_add_slave,
 189         .remove_slave   = w1_default_remove_slave,
 190 };
 191
 192 static struct w1_family w1_default_family = {
 193         .fops = &w1_default_fops,
 194 };
 195
 196 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 197
 198 static struct bus_type w1_bus_type = {
 199         .name = "w1",
 200         .match = w1_master_match,
 201         .uevent = w1_uevent,
 202 };
 203
 204 struct device_driver w1_master_driver = {
 205         .name = "w1_master_driver",
 206         .bus = &w1_bus_type,
 207         .probe = w1_master_probe,
 208 };
 209
 210 struct device w1_master_device = {
 211         .parent = NULL,
 212         .bus = &w1_bus_type,
 213         .bus_id = "w1 bus master",
 214         .driver = &w1_master_driver,
 215         .release = &w1_master_release
 216 };
 217
 218 static struct device_driver w1_slave_driver = {
 219         .name = "w1_slave_driver",
 220         .bus = &w1_bus_type,
 221 };
 222
 223 #if 0
 224 struct device w1_slave_device = {
 225         .parent = NULL,
 226         .bus = &w1_bus_type,
 227         .bus_id = "w1 bus slave",
 228         .driver = &w1_slave_driver,
 229         .release = &w1_slave_release
 230 };
 231 #endif  /*  0  */
 232
 233 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 234 {
 235         struct w1_master *md = dev_to_w1_master(dev);
 236         ssize_t count;
 237
 238         mutex_lock(&md->mutex);
 239         count = sprintf(buf, "%s\n", md->name);
 240         mutex_unlock(&md->mutex);
 241
 242         return count;
 243 }
 244
 245 static ssize_t w1_master_attribute_store_search(struct device * dev,
 246                                                 struct device_attribute *attr,
 247                                                 const char * buf, size_t count)
 248 {
 249         struct w1_master *md = dev_to_w1_master(dev);
 250
 251         mutex_lock(&md->mutex);
 252         md->search_count = simple_strtol(buf, NULL, 0);
 253         mutex_unlock(&md->mutex);
 254
 255         return count;
 256 }
 257
 258 static ssize_t w1_master_attribute_show_search(struct device *dev,
 259                                                struct device_attribute *attr,
 260                                                char *buf)
 261 {
 262         struct w1_master *md = dev_to_w1_master(dev);
 263         ssize_t count;
 264
 265         mutex_lock(&md->mutex);
 266         count = sprintf(buf, "%d\n", md->search_count);
 267         mutex_unlock(&md->mutex);
 268
 269         return count;
 270 }
 271
 272 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 273 {
 274         struct w1_master *md = dev_to_w1_master(dev);
 275         ssize_t count;
 276
 277         mutex_lock(&md->mutex);
 278         count = sprintf(buf, "0x%p\n", md->bus_master);
 279         mutex_unlock(&md->mutex);
 280         return count;
 281 }
 282
 283 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 284 {
 285         ssize_t count;
 286         count = sprintf(buf, "%d\n", w1_timeout);
 287         return count;
 288 }
 289
 290 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 291 {
 292         struct w1_master *md = dev_to_w1_master(dev);
 293         ssize_t count;
 294
 295         mutex_lock(&md->mutex);
 296         count = sprintf(buf, "%d\n", md->max_slave_count);
 297         mutex_unlock(&md->mutex);
 298         return count;
 299 }
 300
 301 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 302 {
 303         struct w1_master *md = dev_to_w1_master(dev);
 304         ssize_t count;
 305
 306         mutex_lock(&md->mutex);
 307         count = sprintf(buf, "%lu\n", md->attempts);
 308         mutex_unlock(&md->mutex);
 309         return count;
 310 }
 311
 312 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 313 {
 314         struct w1_master *md = dev_to_w1_master(dev);
 315         ssize_t count;
 316
 317         mutex_lock(&md->mutex);
 318         count = sprintf(buf, "%d\n", md->slave_count);
 319         mutex_unlock(&md->mutex);
 320         return count;
 321 }
 322
 323 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 324 {
 325         struct w1_master *md = dev_to_w1_master(dev);
 326         int c = PAGE_SIZE;
 327
 328         mutex_lock(&md->mutex);
 329
 330         if (md->slave_count == 0)
 331                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 332         else {
 333                 struct list_head *ent, *n;
 334                 struct w1_slave *sl;
 335
 336                 list_for_each_safe(ent, n, &md->slist) {
 337                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 338
 339                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 340                 }
 341         }
 342
 343         mutex_unlock(&md->mutex);
 344
 345         return PAGE_SIZE - c;
 346 }
 347
 348 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 349         struct device_attribute w1_master_attribute_##_name =   \
 350                 __ATTR(w1_master_##_name, _mode,                \
 351                        w1_master_attribute_show_##_name, NULL)
 352
 353 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 354         struct device_attribute w1_master_attribute_##_name =   \
 355                 __ATTR(w1_master_##_name, _mode,                \
 356                        w1_master_attribute_show_##_name,        \
 357                        w1_master_attribute_store_##_name)
 358
 359 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 360 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 361 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 362 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 363 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 364 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 365 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 366 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 367
 368 static struct attribute *w1_master_default_attrs[] = {
 369         &w1_master_attribute_name.attr,
 370         &w1_master_attribute_slaves.attr,
 371         &w1_master_attribute_slave_count.attr,
 372         &w1_master_attribute_max_slave_count.attr,
 373         &w1_master_attribute_attempts.attr,
 374         &w1_master_attribute_timeout.attr,
 375         &w1_master_attribute_pointer.attr,
 376         &w1_master_attribute_search.attr,
 377         NULL
 378 };
 379
 380 static struct attribute_group w1_master_defattr_group = {
 381         .attrs = w1_master_default_attrs,
 382 };
 383
 384 int w1_create_master_attributes(struct w1_master *master)
 385 {
 386         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 387 }
 388
 389 void w1_destroy_master_attributes(struct w1_master *master)
 390 {
 391         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 392 }
 393
 394 #ifdef CONFIG_HOTPLUG
 395 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 396 {
 397         struct w1_master *md = NULL;
 398         struct w1_slave *sl = NULL;
 399         char *event_owner, *name;
 400         int err;
 401
 402         if (dev->driver == &w1_master_driver) {
 403                 md = container_of(dev, struct w1_master, dev);
 404                 event_owner = "master";
 405                 name = md->name;
 406         } else if (dev->driver == &w1_slave_driver) {
 407                 sl = container_of(dev, struct w1_slave, dev);
 408                 event_owner = "slave";
 409                 name = sl->name;
 410         } else {
 411                 dev_dbg(dev, "Unknown event.\n");
 412                 return -EINVAL;
 413         }
 414
 415         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 416                         event_owner, name, dev->bus_id);
 417
 418         if (dev->driver != &w1_slave_driver || !sl)
 419                 return 0;
 420
 421         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 422         if (err)
 423                 return err;
 424
 425         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 426                              (unsigned long long)sl->reg_num.id);
 427         if (err)
 428                 return err;
 429
 430         return 0;
 431 };
 432 #else
 433 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 434 {
 435         return 0;
 436 }
 437 #endif
 438
 439 static int __w1_attach_slave_device(struct w1_slave *sl)
 440 {
 441         int err;
 442
 443         sl->dev.parent = &sl->master->dev;
 444         sl->dev.driver = &w1_slave_driver;
 445         sl->dev.bus = &w1_bus_type;
 446         sl->dev.release = &w1_slave_release;
 447
 448         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 449                  "%02x-%012llx",
 450                  (unsigned int) sl->reg_num.family,
 451                  (unsigned long long) sl->reg_num.id);
 452         snprintf(&sl->name[0], sizeof(sl->name),
 453                  "%02x-%012llx",
 454                  (unsigned int) sl->reg_num.family,
 455                  (unsigned long long) sl->reg_num.id);
 456
 457         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 458                 &sl->dev.bus_id[0], sl);
 459
 460         err = device_register(&sl->dev);
 461         if (err < 0) {
 462                 dev_err(&sl->dev,
 463                         "Device registration [%s] failed. err=%d\n",
 464                         sl->dev.bus_id, err);
 465                 return err;
 466         }
 467
 468         /* Create "name" entry */
 469         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 470         if (err < 0) {
 471                 dev_err(&sl->dev,
 472                         "sysfs file creation for [%s] failed. err=%d\n",
 473                         sl->dev.bus_id, err);
 474                 goto out_unreg;
 475         }
 476
 477         /* Create "id" entry */
 478         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 479         if (err < 0) {
 480                 dev_err(&sl->dev,
 481                         "sysfs file creation for [%s] failed. err=%d\n",
 482                         sl->dev.bus_id, err);
 483                 goto out_rem1;
 484         }
 485
 486         /* if the family driver needs to initialize something... */
 487         if (sl->family->fops && sl->family->fops->add_slave &&
 488             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 489                 dev_err(&sl->dev,
 490                         "sysfs file creation for [%s] failed. err=%d\n",
 491                         sl->dev.bus_id, err);
 492                 goto out_rem2;
 493         }
 494
 495         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 496
 497         return 0;
 498
 499 out_rem2:
 500         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 501 out_rem1:
 502         device_remove_file(&sl->dev, &w1_slave_attr_name);
 503 out_unreg:
 504         device_unregister(&sl->dev);
 505         return err;
 506 }
 507
 508 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 509 {
 510         struct w1_slave *sl;
 511         struct w1_family *f;
 512         int err;
 513         struct w1_netlink_msg msg;
 514
 515         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 516         if (!sl) {
 517                 dev_err(&dev->dev,
 518                          "%s: failed to allocate new slave device.\n",
 519                          __func__);
 520                 return -ENOMEM;
 521         }
 522
 523
 524         sl->owner = THIS_MODULE;
 525         sl->master = dev;
 526         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 527
 528         memset(&msg, 0, sizeof(msg));
 529         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 530         atomic_set(&sl->refcnt, 0);
 531         init_completion(&sl->released);
 532
 533         spin_lock(&w1_flock);
 534         f = w1_family_registered(rn->family);
 535         if (!f) {
 536                 f= &w1_default_family;
 537                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 538                           rn->family, rn->family,
 539                           (unsigned long long)rn->id, rn->crc);
 540         }
 541         __w1_family_get(f);
 542         spin_unlock(&w1_flock);
 543
 544         sl->family = f;
 545
 546
 547         err = __w1_attach_slave_device(sl);
 548         if (err < 0) {
 549                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 550                          sl->name);
 551                 w1_family_put(sl->family);
 552                 kfree(sl);
 553                 return err;
 554         }
 555
 556         sl->ttl = dev->slave_ttl;
 557         dev->slave_count++;
 558
 559         memcpy(msg.id.id, rn, sizeof(msg.id));
 560         msg.type = W1_SLAVE_ADD;
 561         w1_netlink_send(dev, &msg);
 562
 563         return 0;
 564 }
 565
 566 void w1_slave_detach(struct w1_slave *sl)
 567 {
 568         struct w1_netlink_msg msg;
 569
 570         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 571
 572         list_del(&sl->w1_slave_entry);
 573
 574         if (sl->family->fops && sl->family->fops->remove_slave)
 575                 sl->family->fops->remove_slave(sl);
 576
 577         memset(&msg, 0, sizeof(msg));
 578         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 579         msg.type = W1_SLAVE_REMOVE;
 580         w1_netlink_send(sl->master, &msg);
 581
 582         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 583         device_remove_file(&sl->dev, &w1_slave_attr_name);
 584         device_unregister(&sl->dev);
 585
 586         wait_for_completion(&sl->released);
 587         kfree(sl);
 588 }
 589
 590 struct w1_master *w1_search_master_id(u32 id)
 591 {
 592         struct w1_master *dev;
 593         int found = 0;
 594
 595         mutex_lock(&w1_mlock);
 596         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 597                 if (dev->id == id) {
 598                         found = 1;
 599                         atomic_inc(&dev->refcnt);
 600                         break;
 601                 }
 602         }
 603         mutex_unlock(&w1_mlock);
 604
 605         return (found)?dev:NULL;
 606 }
 607
 608 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 609 {
 610         struct w1_master *dev;
 611         struct w1_slave *sl = NULL;
 612         int found = 0;
 613
 614         mutex_lock(&w1_mlock);
 615         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 616                 mutex_lock(&dev->mutex);
 617                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 618                         if (sl->reg_num.family == id->family &&
 619                                         sl->reg_num.id == id->id &&
 620                                         sl->reg_num.crc == id->crc) {
 621                                 found = 1;
 622                                 atomic_inc(&dev->refcnt);
 623                                 atomic_inc(&sl->refcnt);
 624                                 break;
 625                         }
 626                 }
 627                 mutex_unlock(&dev->mutex);
 628
 629                 if (found)
 630                         break;
 631         }
 632         mutex_unlock(&w1_mlock);
 633
 634         return (found)?sl:NULL;
 635 }
 636
 637 void w1_reconnect_slaves(struct w1_family *f, int attach)
 638 {
 639         struct w1_slave *sl, *sln;
 640         struct w1_master *dev;
 641
 642         mutex_lock(&w1_mlock);
 643         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 644                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 645                         "for family %02x.\n", dev->name, f->fid);
 646                 mutex_lock(&dev->mutex);
 647                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 648                         /* If it is a new family, slaves with the default
 649                          * family driver and are that family will be
 650                          * connected.  If the family is going away, devices
 651                          * matching that family are reconneced.
 652                          */
 653                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 654                                 && sl->reg_num.family == f->fid) ||
 655                                 (!attach && sl->family->fid == f->fid)) {
 656                                 struct w1_reg_num rn;
 657
 658                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 659                                 w1_slave_detach(sl);
 660
 661                                 w1_attach_slave_device(dev, &rn);
 662                         }
 663                 }
 664                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 665                         "has been finished.\n", dev->name);
 666                 mutex_unlock(&dev->mutex);
 667         }
 668         mutex_unlock(&w1_mlock);
 669 }
 670
 671 static void w1_slave_found(struct w1_master *dev, u64 rn)
 672 {
 673         int slave_count;
 674         struct w1_slave *sl;
 675         struct list_head *ent;
 676         struct w1_reg_num *tmp;
 677         u64 rn_le = cpu_to_le64(rn);
 678
 679         atomic_inc(&dev->refcnt);
 680
 681         tmp = (struct w1_reg_num *) &rn;
 682
 683         slave_count = 0;
 684         list_for_each(ent, &dev->slist) {
 685
 686                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 687
 688                 if (sl->reg_num.family == tmp->family &&
 689                     sl->reg_num.id == tmp->id &&
 690                     sl->reg_num.crc == tmp->crc) {
 691                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 692                         break;
 693                 }
 694
 695                 slave_count++;
 696         }
 697
 698         if (slave_count == dev->slave_count &&
 699                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 700                 w1_attach_slave_device(dev, tmp);
 701         }
 702
 703         atomic_dec(&dev->refcnt);
 704 }
 705
 706 /**
 707  * Performs a ROM Search & registers any devices found.
 708  * The 1-wire search is a simple binary tree search.
 709  * For each bit of the address, we read two bits and write one bit.
 710  * The bit written will put to sleep all devies that don't match that bit.
 711  * When the two reads differ, the direction choice is obvious.
 712  * When both bits are 0, we must choose a path to take.
 713  * When we can scan all 64 bits without having to choose a path, we are done.
 714  *
 715  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 716  *
 717  * @dev        The master device to search
 718  * @cb         Function to call when a device is found
 719  */
 720 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 721 {
 722         u64 last_rn, rn, tmp64;
 723         int i, slave_count = 0;
 724         int last_zero, last_device;
 725         int search_bit, desc_bit;
 726         u8  triplet_ret = 0;
 727
 728         search_bit = 0;
 729         rn = last_rn = 0;
 730         last_device = 0;
 731         last_zero = -1;
 732
 733         desc_bit = 64;
 734
 735         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 736                 last_rn = rn;
 737                 rn = 0;
 738
 739                 /*
 740                  * Reset bus and all 1-wire device state machines
 741                  * so they can respond to our requests.
 742                  *
 743                  * Return 0 - device(s) present, 1 - no devices present.
 744                  */
 745                 if (w1_reset_bus(dev)) {
 746                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 747                         break;
 748                 }
 749
 750                 /* Start the search */
 751                 w1_write_8(dev, search_type);
 752                 for (i = 0; i < 64; ++i) {
 753                         /* Determine the direction/search bit */
 754                         if (i == desc_bit)
 755                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 756                         else if (i > desc_bit)
 757                                 search_bit = 0;   /* take the 0 path on the next branch */
 758                         else
 759                                 search_bit = ((last_rn >> i) & 0x1);
 760
 761                         /** Read two bits and write one bit */
 762                         triplet_ret = w1_triplet(dev, search_bit);
 763
 764                         /* quit if no device responded */
 765                         if ( (triplet_ret & 0x03) == 0x03 )
 766                                 break;
 767
 768                         /* If both directions were valid, and we took the 0 path... */
 769                         if (triplet_ret == 0)
 770                                 last_zero = i;
 771
 772                         /* extract the direction taken & update the device number */
 773                         tmp64 = (triplet_ret >> 2);
 774                         rn |= (tmp64 << i);
 775
 776                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 777                                 printk(KERN_INFO "Abort w1_search (exiting)\n");
 778                                 return;
 779                         }
 780                 }
 781
 782                 if ( (triplet_ret & 0x03) != 0x03 ) {
 783                         if ( (desc_bit == last_zero) || (last_zero < 0))
 784                                 last_device = 1;
 785                         desc_bit = last_zero;
 786                         cb(dev, rn);
 787                 }
 788         }
 789 }
 790
 791 void w1_search_process(struct w1_master *dev, u8 search_type)
 792 {
 793         struct w1_slave *sl, *sln;
 794
 795         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 796                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 797
 798         w1_search_devices(dev, search_type, w1_slave_found);
 799
 800         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 801                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
 802                         w1_slave_detach(sl);
 803                 else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 804                         sl->ttl = dev->slave_ttl;
 805         }
 806
 807         if (dev->search_count > 0)
 808                 dev->search_count--;
 809 }
 810
 811 int w1_process(void *data)
 812 {
 813         struct w1_master *dev = (struct w1_master *) data;
 814
 815         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 816                 try_to_freeze();
 817                 msleep_interruptible(w1_timeout * 1000);
 818
 819                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 820                         break;
 821
 822                 if (!dev->initialized)
 823                         continue;
 824
 825                 if (dev->search_count == 0)
 826                         continue;
 827
 828                 mutex_lock(&dev->mutex);
 829                 w1_search_process(dev, W1_SEARCH);
 830                 mutex_unlock(&dev->mutex);
 831         }
 832
 833         atomic_dec(&dev->refcnt);
 834
 835         return 0;
 836 }
 837
 838 static int w1_init(void)
 839 {
 840         int retval;
 841
 842         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 843
 844         w1_init_netlink();
 845
 846         retval = bus_register(&w1_bus_type);
 847         if (retval) {
 848                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 849                 goto err_out_exit_init;
 850         }
 851
 852         retval = driver_register(&w1_master_driver);
 853         if (retval) {
 854                 printk(KERN_ERR
 855                         "Failed to register master driver. err=%d.\n",
 856                         retval);
 857                 goto err_out_bus_unregister;
 858         }
 859
 860         retval = driver_register(&w1_slave_driver);
 861         if (retval) {
 862                 printk(KERN_ERR
 863                         "Failed to register master driver. err=%d.\n",
 864                         retval);
 865                 goto err_out_master_unregister;
 866         }
 867
 868         return 0;
 869
 870 #if 0
 871 /* For undoing the slave register if there was a step after it. */
 872 err_out_slave_unregister:
 873         driver_unregister(&w1_slave_driver);
 874 #endif
 875
 876 err_out_master_unregister:
 877         driver_unregister(&w1_master_driver);
 878
 879 err_out_bus_unregister:
 880         bus_unregister(&w1_bus_type);
 881
 882 err_out_exit_init:
 883         return retval;
 884 }
 885
 886 static void w1_fini(void)
 887 {
 888         struct w1_master *dev;
 889
 890         /* Set netlink removal messages and some cleanup */
 891         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 892                 __w1_remove_master_device(dev);
 893
 894         w1_fini_netlink();
 895
 896         driver_unregister(&w1_slave_driver);
 897         driver_unregister(&w1_master_driver);
 898         bus_unregister(&w1_bus_type);
 899 }
 900
 901 module_init(w1_init);
 902 module_exit(w1_fini);