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   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33
  34 #include <asm/atomic.h>
  35
  36 #include "w1.h"
  37 #include "w1_io.h"
  38 #include "w1_log.h"
  39 #include "w1_int.h"
  40 #include "w1_family.h"
  41 #include "w1_netlink.h"
  42
  43 MODULE_LICENSE("GPL");
  44 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  45 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  46
  47 static int w1_timeout = 10;
  48 int w1_max_slave_count = 10;
  49 int w1_max_slave_ttl = 10;
  50
  51 module_param_named(timeout, w1_timeout, int, 0);
  52 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  53 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  54
  55 DEFINE_SPINLOCK(w1_mlock);
  56 LIST_HEAD(w1_masters);
  57
  58 static pid_t control_thread;
  59 static int control_needs_exit;
  60 static DECLARE_COMPLETION(w1_control_complete);
  61
  62 static int w1_master_match(struct device *dev, struct device_driver *drv)
  63 {
  64         return 1;
  65 }
  66
  67 static int w1_master_probe(struct device *dev)
  68 {
  69         return -ENODEV;
  70 }
  71
  72 static int w1_master_remove(struct device *dev)
  73 {
  74         return 0;
  75 }
  76
  77 static void w1_master_release(struct device *dev)
  78 {
  79         struct w1_master *md = container_of(dev, struct w1_master, dev);
  80
  81         complete(&md->dev_released);
  82 }
  83
  84 static void w1_slave_release(struct device *dev)
  85 {
  86         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  87
  88         complete(&sl->dev_released);
  89 }
  90
  91 static ssize_t w1_default_read_name(struct device *dev, char *buf)
  92 {
  93         return sprintf(buf, "No family registered.\n");
  94 }
  95
  96 static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off,
  97                      size_t count)
  98 {
  99         return sprintf(buf, "No family registered.\n");
 100 }
 101
 102 static struct bus_type w1_bus_type = {
 103         .name = "w1",
 104         .match = w1_master_match,
 105 };
 106
 107 struct device_driver w1_driver = {
 108         .name = "w1_driver",
 109         .bus = &w1_bus_type,
 110         .probe = w1_master_probe,
 111         .remove = w1_master_remove,
 112 };
 113
 114 struct device w1_device = {
 115         .parent = NULL,
 116         .bus = &w1_bus_type,
 117         .bus_id = "w1 bus master",
 118         .driver = &w1_driver,
 119         .release = &w1_master_release
 120 };
 121
 122 static struct device_attribute w1_slave_attribute = {
 123         .attr = {
 124                         .name = "name",
 125                         .mode = S_IRUGO,
 126                         .owner = THIS_MODULE
 127         },
 128         .show = &w1_default_read_name,
 129 };
 130
 131 static struct device_attribute w1_slave_attribute_val = {
 132         .attr = {
 133                         .name = "value",
 134                         .mode = S_IRUGO,
 135                         .owner = THIS_MODULE
 136         },
 137         .show = &w1_default_read_name,
 138 };
 139
 140 static ssize_t w1_master_attribute_show_name(struct device *dev, char *buf)
 141 {
 142         struct w1_master *md = container_of (dev, struct w1_master, dev);
 143         ssize_t count;
 144
 145         if (down_interruptible (&md->mutex))
 146                 return -EBUSY;
 147
 148         count = sprintf(buf, "%s\n", md->name);
 149
 150         up(&md->mutex);
 151
 152         return count;
 153 }
 154
 155 static ssize_t w1_master_attribute_show_pointer(struct device *dev, char *buf)
 156 {
 157         struct w1_master *md = container_of(dev, struct w1_master, dev);
 158         ssize_t count;
 159
 160         if (down_interruptible(&md->mutex))
 161                 return -EBUSY;
 162
 163         count = sprintf(buf, "0x%p\n", md->bus_master);
 164
 165         up(&md->mutex);
 166         return count;
 167 }
 168
 169 static ssize_t w1_master_attribute_show_timeout(struct device *dev, char *buf)
 170 {
 171         ssize_t count;
 172         count = sprintf(buf, "%d\n", w1_timeout);
 173         return count;
 174 }
 175
 176 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, char *buf)
 177 {
 178         struct w1_master *md = container_of(dev, struct w1_master, dev);
 179         ssize_t count;
 180
 181         if (down_interruptible(&md->mutex))
 182                 return -EBUSY;
 183
 184         count = sprintf(buf, "%d\n", md->max_slave_count);
 185
 186         up(&md->mutex);
 187         return count;
 188 }
 189
 190 static ssize_t w1_master_attribute_show_attempts(struct device *dev, char *buf)
 191 {
 192         struct w1_master *md = container_of(dev, struct w1_master, dev);
 193         ssize_t count;
 194
 195         if (down_interruptible(&md->mutex))
 196                 return -EBUSY;
 197
 198         count = sprintf(buf, "%lu\n", md->attempts);
 199
 200         up(&md->mutex);
 201         return count;
 202 }
 203
 204 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, char *buf)
 205 {
 206         struct w1_master *md = container_of(dev, struct w1_master, dev);
 207         ssize_t count;
 208
 209         if (down_interruptible(&md->mutex))
 210                 return -EBUSY;
 211
 212         count = sprintf(buf, "%d\n", md->slave_count);
 213
 214         up(&md->mutex);
 215         return count;
 216 }
 217
 218 static ssize_t w1_master_attribute_show_slaves(struct device *dev, char *buf)
 219
 220 {
 221         struct w1_master *md = container_of(dev, struct w1_master, dev);
 222         int c = PAGE_SIZE;
 223
 224         if (down_interruptible(&md->mutex))
 225                 return -EBUSY;
 226
 227         if (md->slave_count == 0)
 228                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 229         else {
 230                 struct list_head *ent, *n;
 231                 struct w1_slave *sl;
 232
 233                 list_for_each_safe(ent, n, &md->slist) {
 234                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 235
 236                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 237                 }
 238         }
 239
 240         up(&md->mutex);
 241
 242         return PAGE_SIZE - c;
 243 }
 244
 245 static struct device_attribute w1_master_attribute_slaves = {
 246         .attr = {
 247                         .name = "w1_master_slaves",
 248                         .mode = S_IRUGO,
 249                         .owner = THIS_MODULE,
 250         },
 251         .show = &w1_master_attribute_show_slaves,
 252 };
 253 static struct device_attribute w1_master_attribute_slave_count = {
 254         .attr = {
 255                         .name = "w1_master_slave_count",
 256                         .mode = S_IRUGO,
 257                         .owner = THIS_MODULE
 258         },
 259         .show = &w1_master_attribute_show_slave_count,
 260 };
 261 static struct device_attribute w1_master_attribute_attempts = {
 262         .attr = {
 263                         .name = "w1_master_attempts",
 264                         .mode = S_IRUGO,
 265                         .owner = THIS_MODULE
 266         },
 267         .show = &w1_master_attribute_show_attempts,
 268 };
 269 static struct device_attribute w1_master_attribute_max_slave_count = {
 270         .attr = {
 271                         .name = "w1_master_max_slave_count",
 272                         .mode = S_IRUGO,
 273                         .owner = THIS_MODULE
 274         },
 275         .show = &w1_master_attribute_show_max_slave_count,
 276 };
 277 static struct device_attribute w1_master_attribute_timeout = {
 278         .attr = {
 279                         .name = "w1_master_timeout",
 280                         .mode = S_IRUGO,
 281                         .owner = THIS_MODULE
 282         },
 283         .show = &w1_master_attribute_show_timeout,
 284 };
 285 static struct device_attribute w1_master_attribute_pointer = {
 286         .attr = {
 287                         .name = "w1_master_pointer",
 288                         .mode = S_IRUGO,
 289                         .owner = THIS_MODULE
 290         },
 291         .show = &w1_master_attribute_show_pointer,
 292 };
 293 static struct device_attribute w1_master_attribute_name = {
 294         .attr = {
 295                         .name = "w1_master_name",
 296                         .mode = S_IRUGO,
 297                         .owner = THIS_MODULE
 298         },
 299         .show = &w1_master_attribute_show_name,
 300 };
 301
 302 static struct bin_attribute w1_slave_bin_attribute = {
 303         .attr = {
 304                         .name = "w1_slave",
 305                         .mode = S_IRUGO,
 306                         .owner = THIS_MODULE,
 307         },
 308         .size = W1_SLAVE_DATA_SIZE,
 309         .read = &w1_default_read_bin,
 310 };
 311
 312 static int __w1_attach_slave_device(struct w1_slave *sl)
 313 {
 314         int err;
 315
 316         sl->dev.parent = &sl->master->dev;
 317         sl->dev.driver = sl->master->driver;
 318         sl->dev.bus = &w1_bus_type;
 319         sl->dev.release = &w1_slave_release;
 320
 321         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 322                   "%02x-%012llx",
 323                   (unsigned int) sl->reg_num.family,
 324                   (unsigned long long) sl->reg_num.id);
 325         snprintf (&sl->name[0], sizeof(sl->name),
 326                   "%02x-%012llx",
 327                   (unsigned int) sl->reg_num.family,
 328                   (unsigned long long) sl->reg_num.id);
 329
 330         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
 331                 &sl->dev.bus_id[0]);
 332
 333         err = device_register(&sl->dev);
 334         if (err < 0) {
 335                 dev_err(&sl->dev,
 336                          "Device registration [%s] failed. err=%d\n",
 337                          sl->dev.bus_id, err);
 338                 return err;
 339         }
 340
 341         memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
 342         memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
 343         memcpy(&sl->attr_val, &w1_slave_attribute_val, sizeof(sl->attr_val));
 344
 345         sl->attr_bin.read = sl->family->fops->rbin;
 346         sl->attr_name.show = sl->family->fops->rname;
 347         sl->attr_val.show = sl->family->fops->rval;
 348         sl->attr_val.attr.name = sl->family->fops->rvalname;
 349
 350         err = device_create_file(&sl->dev, &sl->attr_name);
 351         if (err < 0) {
 352                 dev_err(&sl->dev,
 353                          "sysfs file creation for [%s] failed. err=%d\n",
 354                          sl->dev.bus_id, err);
 355                 device_unregister(&sl->dev);
 356                 return err;
 357         }
 358
 359         err = device_create_file(&sl->dev, &sl->attr_val);
 360         if (err < 0) {
 361                 dev_err(&sl->dev,
 362                          "sysfs file creation for [%s] failed. err=%d\n",
 363                          sl->dev.bus_id, err);
 364                 device_remove_file(&sl->dev, &sl->attr_name);
 365                 device_unregister(&sl->dev);
 366                 return err;
 367         }
 368
 369         err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
 370         if (err < 0) {
 371                 dev_err(&sl->dev,
 372                          "sysfs file creation for [%s] failed. err=%d\n",
 373                          sl->dev.bus_id, err);
 374                 device_remove_file(&sl->dev, &sl->attr_name);
 375                 device_remove_file(&sl->dev, &sl->attr_val);
 376                 device_unregister(&sl->dev);
 377                 return err;
 378         }
 379
 380         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 381
 382         return 0;
 383 }
 384
 385 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 386 {
 387         struct w1_slave *sl;
 388         struct w1_family *f;
 389         int err;
 390         struct w1_netlink_msg msg;
 391
 392         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 393         if (!sl) {
 394                 dev_err(&dev->dev,
 395                          "%s: failed to allocate new slave device.\n",
 396                          __func__);
 397                 return -ENOMEM;
 398         }
 399
 400         memset(sl, 0, sizeof(*sl));
 401
 402         sl->owner = THIS_MODULE;
 403         sl->master = dev;
 404         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 405
 406         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 407         atomic_set(&sl->refcnt, 0);
 408         init_completion(&sl->dev_released);
 409
 410         spin_lock(&w1_flock);
 411         f = w1_family_registered(rn->family);
 412         if (!f) {
 413                 spin_unlock(&w1_flock);
 414                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 415                           rn->family, rn->family,
 416                           (unsigned long long)rn->id, rn->crc);
 417                 kfree(sl);
 418                 return -ENODEV;
 419         }
 420         __w1_family_get(f);
 421         spin_unlock(&w1_flock);
 422
 423         sl->family = f;
 424
 425
 426         err = __w1_attach_slave_device(sl);
 427         if (err < 0) {
 428                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 429                          sl->name);
 430                 w1_family_put(sl->family);
 431                 kfree(sl);
 432                 return err;
 433         }
 434
 435         sl->ttl = dev->slave_ttl;
 436         dev->slave_count++;
 437
 438         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 439         msg.type = W1_SLAVE_ADD;
 440         w1_netlink_send(dev, &msg);
 441
 442         return 0;
 443 }
 444
 445 static void w1_slave_detach(struct w1_slave *sl)
 446 {
 447         struct w1_netlink_msg msg;
 448
 449         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
 450
 451         while (atomic_read(&sl->refcnt)) {
 452                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 453                                 sl->name, atomic_read(&sl->refcnt));
 454
 455                 if (msleep_interruptible(1000))
 456                         flush_signals(current);
 457         }
 458
 459         sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
 460         device_remove_file(&sl->dev, &sl->attr_name);
 461         device_remove_file(&sl->dev, &sl->attr_val);
 462         device_unregister(&sl->dev);
 463         w1_family_put(sl->family);
 464
 465         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 466         msg.type = W1_SLAVE_REMOVE;
 467         w1_netlink_send(sl->master, &msg);
 468 }
 469
 470 static struct w1_master *w1_search_master(unsigned long data)
 471 {
 472         struct w1_master *dev;
 473         int found = 0;
 474
 475         spin_lock_irq(&w1_mlock);
 476         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 477                 if (dev->bus_master->data == data) {
 478                         found = 1;
 479                         atomic_inc(&dev->refcnt);
 480                         break;
 481                 }
 482         }
 483         spin_unlock_irq(&w1_mlock);
 484
 485         return (found)?dev:NULL;
 486 }
 487
 488 void w1_slave_found(unsigned long data, u64 rn)
 489 {
 490         int slave_count;
 491         struct w1_slave *sl;
 492         struct list_head *ent;
 493         struct w1_reg_num *tmp;
 494         int family_found = 0;
 495         struct w1_master *dev;
 496
 497         dev = w1_search_master(data);
 498         if (!dev) {
 499                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 500                                 data);
 501                 return;
 502         }
 503
 504         tmp = (struct w1_reg_num *) &rn;
 505
 506         slave_count = 0;
 507         list_for_each(ent, &dev->slist) {
 508
 509                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 510
 511                 if (sl->reg_num.family == tmp->family &&
 512                     sl->reg_num.id == tmp->id &&
 513                     sl->reg_num.crc == tmp->crc) {
 514                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 515                         break;
 516                 }
 517                 else if (sl->reg_num.family == tmp->family) {
 518                         family_found = 1;
 519                         break;
 520                 }
 521
 522                 slave_count++;
 523         }
 524
 525         rn = cpu_to_le64(rn);
 526
 527         if (slave_count == dev->slave_count &&
 528                 rn && ((le64_to_cpu(rn) >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn, 7)) {
 529                 w1_attach_slave_device(dev, tmp);
 530         }
 531
 532         atomic_dec(&dev->refcnt);
 533 }
 534
 535 void w1_search(struct w1_master *dev)
 536 {
 537         u64 last, rn, tmp;
 538         int i, count = 0;
 539         int last_family_desc, last_zero, last_device;
 540         int search_bit, id_bit, comp_bit, desc_bit;
 541
 542         search_bit = id_bit = comp_bit = 0;
 543         rn = tmp = last = 0;
 544         last_device = last_zero = last_family_desc = 0;
 545
 546         desc_bit = 64;
 547
 548         while (!(id_bit && comp_bit) && !last_device
 549                 && count++ < dev->max_slave_count) {
 550                 last = rn;
 551                 rn = 0;
 552
 553                 last_family_desc = 0;
 554
 555                 /*
 556                  * Reset bus and all 1-wire device state machines
 557                  * so they can respond to our requests.
 558                  *
 559                  * Return 0 - device(s) present, 1 - no devices present.
 560                  */
 561                 if (w1_reset_bus(dev)) {
 562                         dev_info(&dev->dev, "No devices present on the wire.\n");
 563                         break;
 564                 }
 565
 566 #if 1
 567                 w1_write_8(dev, W1_SEARCH);
 568                 for (i = 0; i < 64; ++i) {
 569                         /*
 570                          * Read 2 bits from bus.
 571                          * All who don't sleep must send ID bit and COMPLEMENT ID bit.
 572                          * They actually are ANDed between all senders.
 573                          */
 574                         id_bit = w1_touch_bit(dev, 1);
 575                         comp_bit = w1_touch_bit(dev, 1);
 576
 577                         if (id_bit && comp_bit)
 578                                 break;
 579
 580                         if (id_bit == 0 && comp_bit == 0) {
 581                                 if (i == desc_bit)
 582                                         search_bit = 1;
 583                                 else if (i > desc_bit)
 584                                         search_bit = 0;
 585                                 else
 586                                         search_bit = ((last >> i) & 0x1);
 587
 588                                 if (search_bit == 0) {
 589                                         last_zero = i;
 590                                         if (last_zero < 9)
 591                                                 last_family_desc = last_zero;
 592                                 }
 593
 594                         }
 595                         else
 596                                 search_bit = id_bit;
 597
 598                         tmp = search_bit;
 599                         rn |= (tmp << i);
 600
 601                         /*
 602                          * Write 1 bit to bus
 603                          * and make all who don't have "search_bit" in "i"'th position
 604                          * in it's registration number sleep.
 605                          */
 606                         if (dev->bus_master->touch_bit)
 607                                 w1_touch_bit(dev, search_bit);
 608                         else
 609                                 w1_write_bit(dev, search_bit);
 610
 611                 }
 612 #endif
 613
 614                 if (desc_bit == last_zero)
 615                         last_device = 1;
 616
 617                 desc_bit = last_zero;
 618
 619                 w1_slave_found(dev->bus_master->data, rn);
 620         }
 621 }
 622
 623 int w1_create_master_attributes(struct w1_master *dev)
 624 {
 625         if (    device_create_file(&dev->dev, &w1_master_attribute_slaves) < 0 ||
 626                 device_create_file(&dev->dev, &w1_master_attribute_slave_count) < 0 ||
 627                 device_create_file(&dev->dev, &w1_master_attribute_attempts) < 0 ||
 628                 device_create_file(&dev->dev, &w1_master_attribute_max_slave_count) < 0 ||
 629                 device_create_file(&dev->dev, &w1_master_attribute_timeout) < 0||
 630                 device_create_file(&dev->dev, &w1_master_attribute_pointer) < 0||
 631                 device_create_file(&dev->dev, &w1_master_attribute_name) < 0)
 632                 return -EINVAL;
 633
 634         return 0;
 635 }
 636
 637 void w1_destroy_master_attributes(struct w1_master *dev)
 638 {
 639         device_remove_file(&dev->dev, &w1_master_attribute_slaves);
 640         device_remove_file(&dev->dev, &w1_master_attribute_slave_count);
 641         device_remove_file(&dev->dev, &w1_master_attribute_attempts);
 642         device_remove_file(&dev->dev, &w1_master_attribute_max_slave_count);
 643         device_remove_file(&dev->dev, &w1_master_attribute_timeout);
 644         device_remove_file(&dev->dev, &w1_master_attribute_pointer);
 645         device_remove_file(&dev->dev, &w1_master_attribute_name);
 646 }
 647
 648
 649 int w1_control(void *data)
 650 {
 651         struct w1_slave *sl;
 652         struct w1_master *dev;
 653         struct list_head *ent, *ment, *n, *mn;
 654         int err, have_to_wait = 0;
 655
 656         daemonize("w1_control");
 657         allow_signal(SIGTERM);
 658
 659         while (!control_needs_exit || have_to_wait) {
 660                 have_to_wait = 0;
 661
 662                 try_to_freeze(PF_FREEZE);
 663                 msleep_interruptible(w1_timeout * 1000);
 664
 665                 if (signal_pending(current))
 666                         flush_signals(current);
 667
 668                 list_for_each_safe(ment, mn, &w1_masters) {
 669                         dev = list_entry(ment, struct w1_master, w1_master_entry);
 670
 671                         if (!control_needs_exit && !dev->need_exit)
 672                                 continue;
 673                         /*
 674                          * Little race: we can create thread but not set the flag.
 675                          * Get a chance for external process to set flag up.
 676                          */
 677                         if (!dev->initialized) {
 678                                 have_to_wait = 1;
 679                                 continue;
 680                         }
 681
 682                         spin_lock(&w1_mlock);
 683                         list_del(&dev->w1_master_entry);
 684                         spin_unlock(&w1_mlock);
 685
 686                         if (control_needs_exit) {
 687                                 dev->need_exit = 1;
 688
 689                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 690                                 if (err)
 691                                         dev_err(&dev->dev,
 692                                                  "Failed to send signal to w1 kernel thread %d.\n",
 693                                                  dev->kpid);
 694                         }
 695
 696                         wait_for_completion(&dev->dev_exited);
 697
 698                         list_for_each_safe(ent, n, &dev->slist) {
 699                                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 700
 701                                 if (!sl)
 702                                         dev_warn(&dev->dev,
 703                                                   "%s: slave entry is NULL.\n",
 704                                                   __func__);
 705                                 else {
 706                                         list_del(&sl->w1_slave_entry);
 707
 708                                         w1_slave_detach(sl);
 709                                         kfree(sl);
 710                                 }
 711                         }
 712                         w1_destroy_master_attributes(dev);
 713                         atomic_dec(&dev->refcnt);
 714                 }
 715         }
 716
 717         complete_and_exit(&w1_control_complete, 0);
 718 }
 719
 720 int w1_process(void *data)
 721 {
 722         struct w1_master *dev = (struct w1_master *) data;
 723         struct list_head *ent, *n;
 724         struct w1_slave *sl;
 725
 726         daemonize("%s", dev->name);
 727         allow_signal(SIGTERM);
 728
 729         while (!dev->need_exit) {
 730                 try_to_freeze(PF_FREEZE);
 731                 msleep_interruptible(w1_timeout * 1000);
 732
 733                 if (signal_pending(current))
 734                         flush_signals(current);
 735
 736                 if (dev->need_exit)
 737                         break;
 738
 739                 if (!dev->initialized)
 740                         continue;
 741
 742                 if (down_interruptible(&dev->mutex))
 743                         continue;
 744
 745                 list_for_each_safe(ent, n, &dev->slist) {
 746                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 747
 748                         if (sl)
 749                                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 750                 }
 751
 752                 w1_search_devices(dev, w1_slave_found);
 753
 754                 list_for_each_safe(ent, n, &dev->slist) {
 755                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 756
 757                         if (sl && !test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 758                                 list_del (&sl->w1_slave_entry);
 759
 760                                 w1_slave_detach (sl);
 761                                 kfree (sl);
 762
 763                                 dev->slave_count--;
 764                         }
 765                         else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 766                                 sl->ttl = dev->slave_ttl;
 767                 }
 768                 up(&dev->mutex);
 769         }
 770
 771         atomic_dec(&dev->refcnt);
 772         complete_and_exit(&dev->dev_exited, 0);
 773
 774         return 0;
 775 }
 776
 777 int w1_init(void)
 778 {
 779         int retval;
 780
 781         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 782
 783         retval = bus_register(&w1_bus_type);
 784         if (retval) {
 785                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 786                 goto err_out_exit_init;
 787         }
 788
 789         retval = driver_register(&w1_driver);
 790         if (retval) {
 791                 printk(KERN_ERR
 792                         "Failed to register master driver. err=%d.\n",
 793                         retval);
 794                 goto err_out_bus_unregister;
 795         }
 796
 797         control_thread = kernel_thread(&w1_control, NULL, 0);
 798         if (control_thread < 0) {
 799                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 800                         control_thread);
 801                 retval = control_thread;
 802                 goto err_out_driver_unregister;
 803         }
 804
 805         return 0;
 806
 807 err_out_driver_unregister:
 808         driver_unregister(&w1_driver);
 809
 810 err_out_bus_unregister:
 811         bus_unregister(&w1_bus_type);
 812
 813 err_out_exit_init:
 814         return retval;
 815 }
 816
 817 void w1_fini(void)
 818 {
 819         struct w1_master *dev;
 820         struct list_head *ent, *n;
 821
 822         list_for_each_safe(ent, n, &w1_masters) {
 823                 dev = list_entry(ent, struct w1_master, w1_master_entry);
 824                 __w1_remove_master_device(dev);
 825         }
 826
 827         control_needs_exit = 1;
 828
 829         wait_for_completion(&w1_control_complete);
 830
 831         driver_unregister(&w1_driver);
 832         bus_unregister(&w1_bus_type);
 833 }
 834
 835 module_init(w1_init);
 836 module_exit(w1_fini);