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 #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 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_MUTEX(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         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  79         kfree(md);
  80 }
  81
  82 static void w1_slave_release(struct device *dev)
  83 {
  84         struct w1_slave *sl = dev_to_w1_slave(dev);
  85
  86         printk("%s: Releasing %s.\n", __func__, sl->name);
  87
  88         while (atomic_read(&sl->refcnt)) {
  89                 printk("Waiting for %s to become free: refcnt=%d.\n",
  90                                 sl->name, atomic_read(&sl->refcnt));
  91                 if (msleep_interruptible(1000))
  92                         flush_signals(current);
  93         }
  94
  95         w1_family_put(sl->family);
  96         sl->master->slave_count--;
  97
  98         complete(&sl->released);
  99 }
 100
 101 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 102 {
 103         struct w1_slave *sl = dev_to_w1_slave(dev);
 104
 105         return sprintf(buf, "%s\n", sl->name);
 106 }
 107
 108 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
 109 {
 110         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 111
 112         if (off > 8) {
 113                 count = 0;
 114         } else {
 115                 if (off + count > 8)
 116                         count = 8 - off;
 117
 118                 memcpy(buf, (u8 *)&sl->reg_num, count);
 119         }
 120
 121         return count;
 122 }
 123
 124 static struct device_attribute w1_slave_attr_name =
 125         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 126
 127 static struct bin_attribute w1_slave_attr_bin_id = {
 128       .attr = {
 129               .name = "id",
 130               .mode = S_IRUGO,
 131               .owner = THIS_MODULE,
 132       },
 133       .size = 8,
 134       .read = w1_slave_read_id,
 135 };
 136
 137 /* Default family */
 138
 139 static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
 140 {
 141         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 142
 143         mutex_lock(&sl->master->mutex);
 144         if (w1_reset_select_slave(sl)) {
 145                 count = 0;
 146                 goto out_up;
 147         }
 148
 149         w1_write_block(sl->master, buf, count);
 150
 151 out_up:
 152         mutex_unlock(&sl->master->mutex);
 153         return count;
 154 }
 155
 156 static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
 157 {
 158         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 159
 160         mutex_lock(&sl->master->mutex);
 161         w1_read_block(sl->master, buf, count);
 162         mutex_unlock(&sl->master->mutex);
 163         return count;
 164 }
 165
 166 static struct bin_attribute w1_default_attr = {
 167       .attr = {
 168               .name = "rw",
 169               .mode = S_IRUGO | S_IWUSR,
 170               .owner = THIS_MODULE,
 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, char **envp, int num_envp, char *buffer, int buffer_size);
 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 static 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, char **envp, int num_envp,
 396                         char *buffer, int buffer_size)
 397 {
 398         struct w1_master *md = NULL;
 399         struct w1_slave *sl = NULL;
 400         char *event_owner, *name;
 401         int err, cur_index=0, cur_len=0;
 402
 403         if (dev->driver == &w1_master_driver) {
 404                 md = container_of(dev, struct w1_master, dev);
 405                 event_owner = "master";
 406                 name = md->name;
 407         } else if (dev->driver == &w1_slave_driver) {
 408                 sl = container_of(dev, struct w1_slave, dev);
 409                 event_owner = "slave";
 410                 name = sl->name;
 411         } else {
 412                 dev_dbg(dev, "Unknown event.\n");
 413                 return -EINVAL;
 414         }
 415
 416         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 417                         event_owner, name, dev->bus_id);
 418
 419         if (dev->driver != &w1_slave_driver || !sl)
 420                 return 0;
 421
 422         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 423                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
 424         if (err)
 425                 return err;
 426
 427         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 428                         &cur_len, "W1_SLAVE_ID=%024LX",
 429                         (unsigned long long)sl->reg_num.id);
 430         if (err)
 431                 return err;
 432
 433         return 0;
 434 };
 435 #else
 436 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 437                         char *buffer, int buffer_size)
 438 {
 439         return 0;
 440 }
 441 #endif
 442
 443 static int __w1_attach_slave_device(struct w1_slave *sl)
 444 {
 445         int err;
 446
 447         sl->dev.parent = &sl->master->dev;
 448         sl->dev.driver = &w1_slave_driver;
 449         sl->dev.bus = &w1_bus_type;
 450         sl->dev.release = &w1_slave_release;
 451
 452         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 453                  "%02x-%012llx",
 454                  (unsigned int) sl->reg_num.family,
 455                  (unsigned long long) sl->reg_num.id);
 456         snprintf(&sl->name[0], sizeof(sl->name),
 457                  "%02x-%012llx",
 458                  (unsigned int) sl->reg_num.family,
 459                  (unsigned long long) sl->reg_num.id);
 460
 461         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 462                 &sl->dev.bus_id[0]);
 463
 464         err = device_register(&sl->dev);
 465         if (err < 0) {
 466                 dev_err(&sl->dev,
 467                         "Device registration [%s] failed. err=%d\n",
 468                         sl->dev.bus_id, err);
 469                 return err;
 470         }
 471
 472         /* Create "name" entry */
 473         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 474         if (err < 0) {
 475                 dev_err(&sl->dev,
 476                         "sysfs file creation for [%s] failed. err=%d\n",
 477                         sl->dev.bus_id, err);
 478                 goto out_unreg;
 479         }
 480
 481         /* Create "id" entry */
 482         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 483         if (err < 0) {
 484                 dev_err(&sl->dev,
 485                         "sysfs file creation for [%s] failed. err=%d\n",
 486                         sl->dev.bus_id, err);
 487                 goto out_rem1;
 488         }
 489
 490         /* if the family driver needs to initialize something... */
 491         if (sl->family->fops && sl->family->fops->add_slave &&
 492             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 493                 dev_err(&sl->dev,
 494                         "sysfs file creation for [%s] failed. err=%d\n",
 495                         sl->dev.bus_id, err);
 496                 goto out_rem2;
 497         }
 498
 499         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 500
 501         return 0;
 502
 503 out_rem2:
 504         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 505 out_rem1:
 506         device_remove_file(&sl->dev, &w1_slave_attr_name);
 507 out_unreg:
 508         device_unregister(&sl->dev);
 509         return err;
 510 }
 511
 512 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 513 {
 514         struct w1_slave *sl;
 515         struct w1_family *f;
 516         int err;
 517         struct w1_netlink_msg msg;
 518
 519         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 520         if (!sl) {
 521                 dev_err(&dev->dev,
 522                          "%s: failed to allocate new slave device.\n",
 523                          __func__);
 524                 return -ENOMEM;
 525         }
 526
 527         memset(sl, 0, sizeof(*sl));
 528
 529         sl->owner = THIS_MODULE;
 530         sl->master = dev;
 531         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 532
 533         memset(&msg, 0, sizeof(msg));
 534         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 535         atomic_set(&sl->refcnt, 0);
 536         init_completion(&sl->released);
 537
 538         spin_lock(&w1_flock);
 539         f = w1_family_registered(rn->family);
 540         if (!f) {
 541                 f= &w1_default_family;
 542                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 543                           rn->family, rn->family,
 544                           (unsigned long long)rn->id, rn->crc);
 545         }
 546         __w1_family_get(f);
 547         spin_unlock(&w1_flock);
 548
 549         sl->family = f;
 550
 551
 552         err = __w1_attach_slave_device(sl);
 553         if (err < 0) {
 554                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 555                          sl->name);
 556                 w1_family_put(sl->family);
 557                 kfree(sl);
 558                 return err;
 559         }
 560
 561         sl->ttl = dev->slave_ttl;
 562         dev->slave_count++;
 563
 564         memcpy(msg.id.id, rn, sizeof(msg.id));
 565         msg.type = W1_SLAVE_ADD;
 566         w1_netlink_send(dev, &msg);
 567
 568         return 0;
 569 }
 570
 571 static void w1_slave_detach(struct w1_slave *sl)
 572 {
 573         struct w1_netlink_msg msg;
 574
 575         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 576
 577         list_del(&sl->w1_slave_entry);
 578
 579         if (sl->family->fops && sl->family->fops->remove_slave)
 580                 sl->family->fops->remove_slave(sl);
 581
 582         memset(&msg, 0, sizeof(msg));
 583         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 584         msg.type = W1_SLAVE_REMOVE;
 585         w1_netlink_send(sl->master, &msg);
 586
 587         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 588         device_remove_file(&sl->dev, &w1_slave_attr_name);
 589         device_unregister(&sl->dev);
 590
 591         wait_for_completion(&sl->released);
 592         kfree(sl);
 593 }
 594
 595 static struct w1_master *w1_search_master(void *data)
 596 {
 597         struct w1_master *dev;
 598         int found = 0;
 599
 600         mutex_lock(&w1_mlock);
 601         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 602                 if (dev->bus_master->data == data) {
 603                         found = 1;
 604                         atomic_inc(&dev->refcnt);
 605                         break;
 606                 }
 607         }
 608         mutex_unlock(&w1_mlock);
 609
 610         return (found)?dev:NULL;
 611 }
 612
 613 struct w1_master *w1_search_master_id(u32 id)
 614 {
 615         struct w1_master *dev;
 616         int found = 0;
 617
 618         mutex_lock(&w1_mlock);
 619         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 620                 if (dev->id == id) {
 621                         found = 1;
 622                         atomic_inc(&dev->refcnt);
 623                         break;
 624                 }
 625         }
 626         mutex_unlock(&w1_mlock);
 627
 628         return (found)?dev:NULL;
 629 }
 630
 631 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 632 {
 633         struct w1_master *dev;
 634         struct w1_slave *sl = NULL;
 635         int found = 0;
 636
 637         mutex_lock(&w1_mlock);
 638         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 639                 mutex_lock(&dev->mutex);
 640                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 641                         if (sl->reg_num.family == id->family &&
 642                                         sl->reg_num.id == id->id &&
 643                                         sl->reg_num.crc == id->crc) {
 644                                 found = 1;
 645                                 atomic_inc(&dev->refcnt);
 646                                 atomic_inc(&sl->refcnt);
 647                                 break;
 648                         }
 649                 }
 650                 mutex_unlock(&dev->mutex);
 651
 652                 if (found)
 653                         break;
 654         }
 655         mutex_unlock(&w1_mlock);
 656
 657         return (found)?sl:NULL;
 658 }
 659
 660 void w1_reconnect_slaves(struct w1_family *f)
 661 {
 662         struct w1_master *dev;
 663
 664         mutex_lock(&w1_mlock);
 665         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 666                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 667                                 dev->name, f->fid);
 668                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 669         }
 670         mutex_unlock(&w1_mlock);
 671 }
 672
 673 static void w1_slave_found(void *data, u64 rn)
 674 {
 675         int slave_count;
 676         struct w1_slave *sl;
 677         struct list_head *ent;
 678         struct w1_reg_num *tmp;
 679         int family_found = 0;
 680         struct w1_master *dev;
 681         u64 rn_le = cpu_to_le64(rn);
 682
 683         dev = w1_search_master(data);
 684         if (!dev) {
 685                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 686                        "it is impossible.\n", data);
 687                 return;
 688         }
 689
 690         tmp = (struct w1_reg_num *) &rn;
 691
 692         slave_count = 0;
 693         list_for_each(ent, &dev->slist) {
 694
 695                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 696
 697                 if (sl->reg_num.family == tmp->family &&
 698                     sl->reg_num.id == tmp->id &&
 699                     sl->reg_num.crc == tmp->crc) {
 700                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 701                         break;
 702                 } else if (sl->reg_num.family == tmp->family) {
 703                         family_found = 1;
 704                         break;
 705                 }
 706
 707                 slave_count++;
 708         }
 709
 710         if (slave_count == dev->slave_count &&
 711                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 712                 w1_attach_slave_device(dev, tmp);
 713         }
 714
 715         atomic_dec(&dev->refcnt);
 716 }
 717
 718 /**
 719  * Performs a ROM Search & registers any devices found.
 720  * The 1-wire search is a simple binary tree search.
 721  * For each bit of the address, we read two bits and write one bit.
 722  * The bit written will put to sleep all devies that don't match that bit.
 723  * When the two reads differ, the direction choice is obvious.
 724  * When both bits are 0, we must choose a path to take.
 725  * When we can scan all 64 bits without having to choose a path, we are done.
 726  *
 727  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 728  *
 729  * @dev        The master device to search
 730  * @cb         Function to call when a device is found
 731  */
 732 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 733 {
 734         u64 last_rn, rn, tmp64;
 735         int i, slave_count = 0;
 736         int last_zero, last_device;
 737         int search_bit, desc_bit;
 738         u8  triplet_ret = 0;
 739
 740         search_bit = 0;
 741         rn = last_rn = 0;
 742         last_device = 0;
 743         last_zero = -1;
 744
 745         desc_bit = 64;
 746
 747         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 748                 last_rn = rn;
 749                 rn = 0;
 750
 751                 /*
 752                  * Reset bus and all 1-wire device state machines
 753                  * so they can respond to our requests.
 754                  *
 755                  * Return 0 - device(s) present, 1 - no devices present.
 756                  */
 757                 if (w1_reset_bus(dev)) {
 758                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 759                         break;
 760                 }
 761
 762                 /* Start the search */
 763                 w1_write_8(dev, search_type);
 764                 for (i = 0; i < 64; ++i) {
 765                         /* Determine the direction/search bit */
 766                         if (i == desc_bit)
 767                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 768                         else if (i > desc_bit)
 769                                 search_bit = 0;   /* take the 0 path on the next branch */
 770                         else
 771                                 search_bit = ((last_rn >> i) & 0x1);
 772
 773                         /** Read two bits and write one bit */
 774                         triplet_ret = w1_triplet(dev, search_bit);
 775
 776                         /* quit if no device responded */
 777                         if ( (triplet_ret & 0x03) == 0x03 )
 778                                 break;
 779
 780                         /* If both directions were valid, and we took the 0 path... */
 781                         if (triplet_ret == 0)
 782                                 last_zero = i;
 783
 784                         /* extract the direction taken & update the device number */
 785                         tmp64 = (triplet_ret >> 2);
 786                         rn |= (tmp64 << i);
 787                 }
 788
 789                 if ( (triplet_ret & 0x03) != 0x03 ) {
 790                         if ( (desc_bit == last_zero) || (last_zero < 0))
 791                                 last_device = 1;
 792                         desc_bit = last_zero;
 793                         cb(dev->bus_master->data, rn);
 794                 }
 795         }
 796 }
 797
 798 static int w1_control(void *data)
 799 {
 800         struct w1_slave *sl, *sln;
 801         struct w1_master *dev, *n;
 802         int have_to_wait = 0;
 803
 804         while (!kthread_should_stop() || have_to_wait) {
 805                 have_to_wait = 0;
 806
 807                 try_to_freeze();
 808                 msleep_interruptible(w1_control_timeout * 1000);
 809
 810                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 811                         if (!kthread_should_stop() && !dev->flags)
 812                                 continue;
 813                         /*
 814                          * Little race: we can create thread but not set the flag.
 815                          * Get a chance for external process to set flag up.
 816                          */
 817                         if (!dev->initialized) {
 818                                 have_to_wait = 1;
 819                                 continue;
 820                         }
 821
 822                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 823                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 824
 825                                 mutex_lock(&w1_mlock);
 826                                 list_del(&dev->w1_master_entry);
 827                                 mutex_unlock(&w1_mlock);
 828
 829                                 mutex_lock(&dev->mutex);
 830                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 831                                         w1_slave_detach(sl);
 832                                 }
 833                                 w1_destroy_master_attributes(dev);
 834                                 mutex_unlock(&dev->mutex);
 835                                 atomic_dec(&dev->refcnt);
 836                                 continue;
 837                         }
 838
 839                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 840                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 841                                 mutex_lock(&dev->mutex);
 842                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 843                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 844                                                 struct w1_reg_num rn;
 845
 846                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 847                                                 w1_slave_detach(sl);
 848
 849                                                 w1_attach_slave_device(dev, &rn);
 850                                         }
 851                                 }
 852                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 853                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 854                                 mutex_unlock(&dev->mutex);
 855                         }
 856                 }
 857         }
 858
 859         return 0;
 860 }
 861
 862 void w1_search_process(struct w1_master *dev, u8 search_type)
 863 {
 864         struct w1_slave *sl, *sln;
 865
 866         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 867                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 868
 869         w1_search_devices(dev, search_type, w1_slave_found);
 870
 871         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 872                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 873                         w1_slave_detach(sl);
 874
 875                         dev->slave_count--;
 876                 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 877                         sl->ttl = dev->slave_ttl;
 878         }
 879
 880         if (dev->search_count > 0)
 881                 dev->search_count--;
 882 }
 883
 884 int w1_process(void *data)
 885 {
 886         struct w1_master *dev = (struct w1_master *) data;
 887
 888         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 889                 try_to_freeze();
 890                 msleep_interruptible(w1_timeout * 1000);
 891
 892                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 893                         break;
 894
 895                 if (!dev->initialized)
 896                         continue;
 897
 898                 if (dev->search_count == 0)
 899                         continue;
 900
 901                 mutex_lock(&dev->mutex);
 902                 w1_search_process(dev, W1_SEARCH);
 903                 mutex_unlock(&dev->mutex);
 904         }
 905
 906         atomic_dec(&dev->refcnt);
 907
 908         return 0;
 909 }
 910
 911 static int w1_init(void)
 912 {
 913         int retval;
 914
 915         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 916
 917         w1_init_netlink();
 918
 919         retval = bus_register(&w1_bus_type);
 920         if (retval) {
 921                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 922                 goto err_out_exit_init;
 923         }
 924
 925         retval = driver_register(&w1_master_driver);
 926         if (retval) {
 927                 printk(KERN_ERR
 928                         "Failed to register master driver. err=%d.\n",
 929                         retval);
 930                 goto err_out_bus_unregister;
 931         }
 932
 933         retval = driver_register(&w1_slave_driver);
 934         if (retval) {
 935                 printk(KERN_ERR
 936                         "Failed to register master driver. err=%d.\n",
 937                         retval);
 938                 goto err_out_master_unregister;
 939         }
 940
 941         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 942         if (IS_ERR(w1_control_thread)) {
 943                 retval = PTR_ERR(w1_control_thread);
 944                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 945                         retval);
 946                 goto err_out_slave_unregister;
 947         }
 948
 949         return 0;
 950
 951 err_out_slave_unregister:
 952         driver_unregister(&w1_slave_driver);
 953
 954 err_out_master_unregister:
 955         driver_unregister(&w1_master_driver);
 956
 957 err_out_bus_unregister:
 958         bus_unregister(&w1_bus_type);
 959
 960 err_out_exit_init:
 961         return retval;
 962 }
 963
 964 static void w1_fini(void)
 965 {
 966         struct w1_master *dev;
 967
 968         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 969                 __w1_remove_master_device(dev);
 970
 971         w1_fini_netlink();
 972
 973         kthread_stop(w1_control_thread);
 974
 975         driver_unregister(&w1_slave_driver);
 976         driver_unregister(&w1_master_driver);
 977         bus_unregister(&w1_bus_type);
 978 }
 979
 980 module_init(w1_init);
 981 module_exit(w1_fini);