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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 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,
 109                                 struct bin_attribute *bin_attr,
 110                                 char *buf, loff_t off, size_t count)
 111 {
 112         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 113
 114         if (off > 8) {
 115                 count = 0;
 116         } else {
 117                 if (off + count > 8)
 118                         count = 8 - off;
 119
 120                 memcpy(buf, (u8 *)&sl->reg_num, count);
 121         }
 122
 123         return count;
 124 }
 125
 126 static struct device_attribute w1_slave_attr_name =
 127         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 128
 129 static struct bin_attribute w1_slave_attr_bin_id = {
 130       .attr = {
 131               .name = "id",
 132               .mode = S_IRUGO,
 133       },
 134       .size = 8,
 135       .read = w1_slave_read_id,
 136 };
 137
 138 /* Default family */
 139
 140 static ssize_t w1_default_write(struct kobject *kobj,
 141                                 struct bin_attribute *bin_attr,
 142                                 char *buf, loff_t off, size_t count)
 143 {
 144         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 145
 146         mutex_lock(&sl->master->mutex);
 147         if (w1_reset_select_slave(sl)) {
 148                 count = 0;
 149                 goto out_up;
 150         }
 151
 152         w1_write_block(sl->master, buf, count);
 153
 154 out_up:
 155         mutex_unlock(&sl->master->mutex);
 156         return count;
 157 }
 158
 159 static ssize_t w1_default_read(struct kobject *kobj,
 160                                struct bin_attribute *bin_attr,
 161                                char *buf, loff_t off, size_t count)
 162 {
 163         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 164
 165         mutex_lock(&sl->master->mutex);
 166         w1_read_block(sl->master, buf, count);
 167         mutex_unlock(&sl->master->mutex);
 168         return count;
 169 }
 170
 171 static struct bin_attribute w1_default_attr = {
 172       .attr = {
 173               .name = "rw",
 174               .mode = S_IRUGO | S_IWUSR,
 175       },
 176       .size = PAGE_SIZE,
 177       .read = w1_default_read,
 178       .write = w1_default_write,
 179 };
 180
 181 static int w1_default_add_slave(struct w1_slave *sl)
 182 {
 183         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 184 }
 185
 186 static void w1_default_remove_slave(struct w1_slave *sl)
 187 {
 188         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 189 }
 190
 191 static struct w1_family_ops w1_default_fops = {
 192         .add_slave      = w1_default_add_slave,
 193         .remove_slave   = w1_default_remove_slave,
 194 };
 195
 196 static struct w1_family w1_default_family = {
 197         .fops = &w1_default_fops,
 198 };
 199
 200 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 201
 202 static struct bus_type w1_bus_type = {
 203         .name = "w1",
 204         .match = w1_master_match,
 205         .uevent = w1_uevent,
 206 };
 207
 208 struct device_driver w1_master_driver = {
 209         .name = "w1_master_driver",
 210         .bus = &w1_bus_type,
 211         .probe = w1_master_probe,
 212 };
 213
 214 struct device w1_master_device = {
 215         .parent = NULL,
 216         .bus = &w1_bus_type,
 217         .bus_id = "w1 bus master",
 218         .driver = &w1_master_driver,
 219         .release = &w1_master_release
 220 };
 221
 222 static struct device_driver w1_slave_driver = {
 223         .name = "w1_slave_driver",
 224         .bus = &w1_bus_type,
 225 };
 226
 227 #if 0
 228 struct device w1_slave_device = {
 229         .parent = NULL,
 230         .bus = &w1_bus_type,
 231         .bus_id = "w1 bus slave",
 232         .driver = &w1_slave_driver,
 233         .release = &w1_slave_release
 234 };
 235 #endif  /*  0  */
 236
 237 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 238 {
 239         struct w1_master *md = dev_to_w1_master(dev);
 240         ssize_t count;
 241
 242         mutex_lock(&md->mutex);
 243         count = sprintf(buf, "%s\n", md->name);
 244         mutex_unlock(&md->mutex);
 245
 246         return count;
 247 }
 248
 249 static ssize_t w1_master_attribute_store_search(struct device * dev,
 250                                                 struct device_attribute *attr,
 251                                                 const char * buf, size_t count)
 252 {
 253         struct w1_master *md = dev_to_w1_master(dev);
 254
 255         mutex_lock(&md->mutex);
 256         md->search_count = simple_strtol(buf, NULL, 0);
 257         mutex_unlock(&md->mutex);
 258
 259         return count;
 260 }
 261
 262 static ssize_t w1_master_attribute_show_search(struct device *dev,
 263                                                struct device_attribute *attr,
 264                                                char *buf)
 265 {
 266         struct w1_master *md = dev_to_w1_master(dev);
 267         ssize_t count;
 268
 269         mutex_lock(&md->mutex);
 270         count = sprintf(buf, "%d\n", md->search_count);
 271         mutex_unlock(&md->mutex);
 272
 273         return count;
 274 }
 275
 276 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 277 {
 278         struct w1_master *md = dev_to_w1_master(dev);
 279         ssize_t count;
 280
 281         mutex_lock(&md->mutex);
 282         count = sprintf(buf, "0x%p\n", md->bus_master);
 283         mutex_unlock(&md->mutex);
 284         return count;
 285 }
 286
 287 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 288 {
 289         ssize_t count;
 290         count = sprintf(buf, "%d\n", w1_timeout);
 291         return count;
 292 }
 293
 294 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 295 {
 296         struct w1_master *md = dev_to_w1_master(dev);
 297         ssize_t count;
 298
 299         mutex_lock(&md->mutex);
 300         count = sprintf(buf, "%d\n", md->max_slave_count);
 301         mutex_unlock(&md->mutex);
 302         return count;
 303 }
 304
 305 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 306 {
 307         struct w1_master *md = dev_to_w1_master(dev);
 308         ssize_t count;
 309
 310         mutex_lock(&md->mutex);
 311         count = sprintf(buf, "%lu\n", md->attempts);
 312         mutex_unlock(&md->mutex);
 313         return count;
 314 }
 315
 316 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 317 {
 318         struct w1_master *md = dev_to_w1_master(dev);
 319         ssize_t count;
 320
 321         mutex_lock(&md->mutex);
 322         count = sprintf(buf, "%d\n", md->slave_count);
 323         mutex_unlock(&md->mutex);
 324         return count;
 325 }
 326
 327 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 328 {
 329         struct w1_master *md = dev_to_w1_master(dev);
 330         int c = PAGE_SIZE;
 331
 332         mutex_lock(&md->mutex);
 333
 334         if (md->slave_count == 0)
 335                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 336         else {
 337                 struct list_head *ent, *n;
 338                 struct w1_slave *sl;
 339
 340                 list_for_each_safe(ent, n, &md->slist) {
 341                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 342
 343                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 344                 }
 345         }
 346
 347         mutex_unlock(&md->mutex);
 348
 349         return PAGE_SIZE - c;
 350 }
 351
 352 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 353         struct device_attribute w1_master_attribute_##_name =   \
 354                 __ATTR(w1_master_##_name, _mode,                \
 355                        w1_master_attribute_show_##_name, NULL)
 356
 357 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 358         struct device_attribute w1_master_attribute_##_name =   \
 359                 __ATTR(w1_master_##_name, _mode,                \
 360                        w1_master_attribute_show_##_name,        \
 361                        w1_master_attribute_store_##_name)
 362
 363 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 364 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 365 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 366 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 367 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 368 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 369 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 370 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 371
 372 static struct attribute *w1_master_default_attrs[] = {
 373         &w1_master_attribute_name.attr,
 374         &w1_master_attribute_slaves.attr,
 375         &w1_master_attribute_slave_count.attr,
 376         &w1_master_attribute_max_slave_count.attr,
 377         &w1_master_attribute_attempts.attr,
 378         &w1_master_attribute_timeout.attr,
 379         &w1_master_attribute_pointer.attr,
 380         &w1_master_attribute_search.attr,
 381         NULL
 382 };
 383
 384 static struct attribute_group w1_master_defattr_group = {
 385         .attrs = w1_master_default_attrs,
 386 };
 387
 388 int w1_create_master_attributes(struct w1_master *master)
 389 {
 390         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 391 }
 392
 393 static void w1_destroy_master_attributes(struct w1_master *master)
 394 {
 395         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 396 }
 397
 398 #ifdef CONFIG_HOTPLUG
 399 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 400                         char *buffer, int buffer_size)
 401 {
 402         struct w1_master *md = NULL;
 403         struct w1_slave *sl = NULL;
 404         char *event_owner, *name;
 405         int err, cur_index=0, cur_len=0;
 406
 407         if (dev->driver == &w1_master_driver) {
 408                 md = container_of(dev, struct w1_master, dev);
 409                 event_owner = "master";
 410                 name = md->name;
 411         } else if (dev->driver == &w1_slave_driver) {
 412                 sl = container_of(dev, struct w1_slave, dev);
 413                 event_owner = "slave";
 414                 name = sl->name;
 415         } else {
 416                 dev_dbg(dev, "Unknown event.\n");
 417                 return -EINVAL;
 418         }
 419
 420         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 421                         event_owner, name, dev->bus_id);
 422
 423         if (dev->driver != &w1_slave_driver || !sl)
 424                 return 0;
 425
 426         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 427                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
 428         if (err)
 429                 return err;
 430
 431         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 432                         &cur_len, "W1_SLAVE_ID=%024LX",
 433                         (unsigned long long)sl->reg_num.id);
 434         if (err)
 435                 return err;
 436
 437         return 0;
 438 };
 439 #else
 440 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 441                         char *buffer, int buffer_size)
 442 {
 443         return 0;
 444 }
 445 #endif
 446
 447 static int __w1_attach_slave_device(struct w1_slave *sl)
 448 {
 449         int err;
 450
 451         sl->dev.parent = &sl->master->dev;
 452         sl->dev.driver = &w1_slave_driver;
 453         sl->dev.bus = &w1_bus_type;
 454         sl->dev.release = &w1_slave_release;
 455
 456         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 457                  "%02x-%012llx",
 458                  (unsigned int) sl->reg_num.family,
 459                  (unsigned long long) sl->reg_num.id);
 460         snprintf(&sl->name[0], sizeof(sl->name),
 461                  "%02x-%012llx",
 462                  (unsigned int) sl->reg_num.family,
 463                  (unsigned long long) sl->reg_num.id);
 464
 465         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 466                 &sl->dev.bus_id[0], sl);
 467
 468         err = device_register(&sl->dev);
 469         if (err < 0) {
 470                 dev_err(&sl->dev,
 471                         "Device registration [%s] failed. err=%d\n",
 472                         sl->dev.bus_id, err);
 473                 return err;
 474         }
 475
 476         /* Create "name" entry */
 477         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 478         if (err < 0) {
 479                 dev_err(&sl->dev,
 480                         "sysfs file creation for [%s] failed. err=%d\n",
 481                         sl->dev.bus_id, err);
 482                 goto out_unreg;
 483         }
 484
 485         /* Create "id" entry */
 486         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 487         if (err < 0) {
 488                 dev_err(&sl->dev,
 489                         "sysfs file creation for [%s] failed. err=%d\n",
 490                         sl->dev.bus_id, err);
 491                 goto out_rem1;
 492         }
 493
 494         /* if the family driver needs to initialize something... */
 495         if (sl->family->fops && sl->family->fops->add_slave &&
 496             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 497                 dev_err(&sl->dev,
 498                         "sysfs file creation for [%s] failed. err=%d\n",
 499                         sl->dev.bus_id, err);
 500                 goto out_rem2;
 501         }
 502
 503         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 504
 505         return 0;
 506
 507 out_rem2:
 508         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 509 out_rem1:
 510         device_remove_file(&sl->dev, &w1_slave_attr_name);
 511 out_unreg:
 512         device_unregister(&sl->dev);
 513         return err;
 514 }
 515
 516 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 517 {
 518         struct w1_slave *sl;
 519         struct w1_family *f;
 520         int err;
 521         struct w1_netlink_msg msg;
 522
 523         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 524         if (!sl) {
 525                 dev_err(&dev->dev,
 526                          "%s: failed to allocate new slave device.\n",
 527                          __func__);
 528                 return -ENOMEM;
 529         }
 530
 531
 532         sl->owner = THIS_MODULE;
 533         sl->master = dev;
 534         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 535
 536         memset(&msg, 0, sizeof(msg));
 537         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 538         atomic_set(&sl->refcnt, 0);
 539         init_completion(&sl->released);
 540
 541         spin_lock(&w1_flock);
 542         f = w1_family_registered(rn->family);
 543         if (!f) {
 544                 f= &w1_default_family;
 545                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 546                           rn->family, rn->family,
 547                           (unsigned long long)rn->id, rn->crc);
 548         }
 549         __w1_family_get(f);
 550         spin_unlock(&w1_flock);
 551
 552         sl->family = f;
 553
 554
 555         err = __w1_attach_slave_device(sl);
 556         if (err < 0) {
 557                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 558                          sl->name);
 559                 w1_family_put(sl->family);
 560                 kfree(sl);
 561                 return err;
 562         }
 563
 564         sl->ttl = dev->slave_ttl;
 565         dev->slave_count++;
 566
 567         memcpy(msg.id.id, rn, sizeof(msg.id));
 568         msg.type = W1_SLAVE_ADD;
 569         w1_netlink_send(dev, &msg);
 570
 571         return 0;
 572 }
 573
 574 static void w1_slave_detach(struct w1_slave *sl)
 575 {
 576         struct w1_netlink_msg msg;
 577
 578         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 579
 580         list_del(&sl->w1_slave_entry);
 581
 582         if (sl->family->fops && sl->family->fops->remove_slave)
 583                 sl->family->fops->remove_slave(sl);
 584
 585         memset(&msg, 0, sizeof(msg));
 586         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 587         msg.type = W1_SLAVE_REMOVE;
 588         w1_netlink_send(sl->master, &msg);
 589
 590         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 591         device_remove_file(&sl->dev, &w1_slave_attr_name);
 592         device_unregister(&sl->dev);
 593
 594         wait_for_completion(&sl->released);
 595         kfree(sl);
 596 }
 597
 598 static struct w1_master *w1_search_master(void *data)
 599 {
 600         struct w1_master *dev;
 601         int found = 0;
 602
 603         mutex_lock(&w1_mlock);
 604         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 605                 if (dev->bus_master->data == data) {
 606                         found = 1;
 607                         atomic_inc(&dev->refcnt);
 608                         break;
 609                 }
 610         }
 611         mutex_unlock(&w1_mlock);
 612
 613         return (found)?dev:NULL;
 614 }
 615
 616 struct w1_master *w1_search_master_id(u32 id)
 617 {
 618         struct w1_master *dev;
 619         int found = 0;
 620
 621         mutex_lock(&w1_mlock);
 622         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 623                 if (dev->id == id) {
 624                         found = 1;
 625                         atomic_inc(&dev->refcnt);
 626                         break;
 627                 }
 628         }
 629         mutex_unlock(&w1_mlock);
 630
 631         return (found)?dev:NULL;
 632 }
 633
 634 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 635 {
 636         struct w1_master *dev;
 637         struct w1_slave *sl = NULL;
 638         int found = 0;
 639
 640         mutex_lock(&w1_mlock);
 641         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 642                 mutex_lock(&dev->mutex);
 643                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 644                         if (sl->reg_num.family == id->family &&
 645                                         sl->reg_num.id == id->id &&
 646                                         sl->reg_num.crc == id->crc) {
 647                                 found = 1;
 648                                 atomic_inc(&dev->refcnt);
 649                                 atomic_inc(&sl->refcnt);
 650                                 break;
 651                         }
 652                 }
 653                 mutex_unlock(&dev->mutex);
 654
 655                 if (found)
 656                         break;
 657         }
 658         mutex_unlock(&w1_mlock);
 659
 660         return (found)?sl:NULL;
 661 }
 662
 663 void w1_reconnect_slaves(struct w1_family *f)
 664 {
 665         struct w1_master *dev;
 666
 667         mutex_lock(&w1_mlock);
 668         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 669                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 670                                 dev->name, f->fid);
 671                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 672         }
 673         mutex_unlock(&w1_mlock);
 674 }
 675
 676 static void w1_slave_found(void *data, u64 rn)
 677 {
 678         int slave_count;
 679         struct w1_slave *sl;
 680         struct list_head *ent;
 681         struct w1_reg_num *tmp;
 682         int family_found = 0;
 683         struct w1_master *dev;
 684         u64 rn_le = cpu_to_le64(rn);
 685
 686         dev = w1_search_master(data);
 687         if (!dev) {
 688                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 689                        "it is impossible.\n", data);
 690                 return;
 691         }
 692
 693         tmp = (struct w1_reg_num *) &rn;
 694
 695         slave_count = 0;
 696         list_for_each(ent, &dev->slist) {
 697
 698                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 699
 700                 if (sl->reg_num.family == tmp->family &&
 701                     sl->reg_num.id == tmp->id &&
 702                     sl->reg_num.crc == tmp->crc) {
 703                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 704                         break;
 705                 } else if (sl->reg_num.family == tmp->family) {
 706                         family_found = 1;
 707                         break;
 708                 }
 709
 710                 slave_count++;
 711         }
 712
 713         if (slave_count == dev->slave_count &&
 714                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 715                 w1_attach_slave_device(dev, tmp);
 716         }
 717
 718         atomic_dec(&dev->refcnt);
 719 }
 720
 721 /**
 722  * Performs a ROM Search & registers any devices found.
 723  * The 1-wire search is a simple binary tree search.
 724  * For each bit of the address, we read two bits and write one bit.
 725  * The bit written will put to sleep all devies that don't match that bit.
 726  * When the two reads differ, the direction choice is obvious.
 727  * When both bits are 0, we must choose a path to take.
 728  * When we can scan all 64 bits without having to choose a path, we are done.
 729  *
 730  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 731  *
 732  * @dev        The master device to search
 733  * @cb         Function to call when a device is found
 734  */
 735 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 736 {
 737         u64 last_rn, rn, tmp64;
 738         int i, slave_count = 0;
 739         int last_zero, last_device;
 740         int search_bit, desc_bit;
 741         u8  triplet_ret = 0;
 742
 743         search_bit = 0;
 744         rn = last_rn = 0;
 745         last_device = 0;
 746         last_zero = -1;
 747
 748         desc_bit = 64;
 749
 750         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 751                 last_rn = rn;
 752                 rn = 0;
 753
 754                 /*
 755                  * Reset bus and all 1-wire device state machines
 756                  * so they can respond to our requests.
 757                  *
 758                  * Return 0 - device(s) present, 1 - no devices present.
 759                  */
 760                 if (w1_reset_bus(dev)) {
 761                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 762                         break;
 763                 }
 764
 765                 /* Start the search */
 766                 w1_write_8(dev, search_type);
 767                 for (i = 0; i < 64; ++i) {
 768                         /* Determine the direction/search bit */
 769                         if (i == desc_bit)
 770                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 771                         else if (i > desc_bit)
 772                                 search_bit = 0;   /* take the 0 path on the next branch */
 773                         else
 774                                 search_bit = ((last_rn >> i) & 0x1);
 775
 776                         /** Read two bits and write one bit */
 777                         triplet_ret = w1_triplet(dev, search_bit);
 778
 779                         /* quit if no device responded */
 780                         if ( (triplet_ret & 0x03) == 0x03 )
 781                                 break;
 782
 783                         /* If both directions were valid, and we took the 0 path... */
 784                         if (triplet_ret == 0)
 785                                 last_zero = i;
 786
 787                         /* extract the direction taken & update the device number */
 788                         tmp64 = (triplet_ret >> 2);
 789                         rn |= (tmp64 << i);
 790                 }
 791
 792                 if ( (triplet_ret & 0x03) != 0x03 ) {
 793                         if ( (desc_bit == last_zero) || (last_zero < 0))
 794                                 last_device = 1;
 795                         desc_bit = last_zero;
 796                         cb(dev->bus_master->data, rn);
 797                 }
 798         }
 799 }
 800
 801 static int w1_control(void *data)
 802 {
 803         struct w1_slave *sl, *sln;
 804         struct w1_master *dev, *n;
 805         int have_to_wait = 0;
 806
 807         set_freezable();
 808         while (!kthread_should_stop() || have_to_wait) {
 809                 have_to_wait = 0;
 810
 811                 try_to_freeze();
 812                 msleep_interruptible(w1_control_timeout * 1000);
 813
 814                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 815                         if (!kthread_should_stop() && !dev->flags)
 816                                 continue;
 817                         /*
 818                          * Little race: we can create thread but not set the flag.
 819                          * Get a chance for external process to set flag up.
 820                          */
 821                         if (!dev->initialized) {
 822                                 have_to_wait = 1;
 823                                 continue;
 824                         }
 825
 826                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 827                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 828
 829                                 mutex_lock(&w1_mlock);
 830                                 list_del(&dev->w1_master_entry);
 831                                 mutex_unlock(&w1_mlock);
 832
 833                                 mutex_lock(&dev->mutex);
 834                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 835                                         w1_slave_detach(sl);
 836                                 }
 837                                 w1_destroy_master_attributes(dev);
 838                                 mutex_unlock(&dev->mutex);
 839                                 atomic_dec(&dev->refcnt);
 840                                 continue;
 841                         }
 842
 843                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 844                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 845                                 mutex_lock(&dev->mutex);
 846                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 847                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 848                                                 struct w1_reg_num rn;
 849
 850                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 851                                                 w1_slave_detach(sl);
 852
 853                                                 w1_attach_slave_device(dev, &rn);
 854                                         }
 855                                 }
 856                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 857                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 858                                 mutex_unlock(&dev->mutex);
 859                         }
 860                 }
 861         }
 862
 863         return 0;
 864 }
 865
 866 void w1_search_process(struct w1_master *dev, u8 search_type)
 867 {
 868         struct w1_slave *sl, *sln;
 869
 870         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 871                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 872
 873         w1_search_devices(dev, search_type, w1_slave_found);
 874
 875         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 876                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 877                         w1_slave_detach(sl);
 878
 879                         dev->slave_count--;
 880                 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 881                         sl->ttl = dev->slave_ttl;
 882         }
 883
 884         if (dev->search_count > 0)
 885                 dev->search_count--;
 886 }
 887
 888 int w1_process(void *data)
 889 {
 890         struct w1_master *dev = (struct w1_master *) data;
 891
 892         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 893                 try_to_freeze();
 894                 msleep_interruptible(w1_timeout * 1000);
 895
 896                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 897                         break;
 898
 899                 if (!dev->initialized)
 900                         continue;
 901
 902                 if (dev->search_count == 0)
 903                         continue;
 904
 905                 mutex_lock(&dev->mutex);
 906                 w1_search_process(dev, W1_SEARCH);
 907                 mutex_unlock(&dev->mutex);
 908         }
 909
 910         atomic_dec(&dev->refcnt);
 911
 912         return 0;
 913 }
 914
 915 static int w1_init(void)
 916 {
 917         int retval;
 918
 919         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 920
 921         w1_init_netlink();
 922
 923         retval = bus_register(&w1_bus_type);
 924         if (retval) {
 925                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 926                 goto err_out_exit_init;
 927         }
 928
 929         retval = driver_register(&w1_master_driver);
 930         if (retval) {
 931                 printk(KERN_ERR
 932                         "Failed to register master driver. err=%d.\n",
 933                         retval);
 934                 goto err_out_bus_unregister;
 935         }
 936
 937         retval = driver_register(&w1_slave_driver);
 938         if (retval) {
 939                 printk(KERN_ERR
 940                         "Failed to register master driver. err=%d.\n",
 941                         retval);
 942                 goto err_out_master_unregister;
 943         }
 944
 945         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 946         if (IS_ERR(w1_control_thread)) {
 947                 retval = PTR_ERR(w1_control_thread);
 948                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 949                         retval);
 950                 goto err_out_slave_unregister;
 951         }
 952
 953         return 0;
 954
 955 err_out_slave_unregister:
 956         driver_unregister(&w1_slave_driver);
 957
 958 err_out_master_unregister:
 959         driver_unregister(&w1_master_driver);
 960
 961 err_out_bus_unregister:
 962         bus_unregister(&w1_bus_type);
 963
 964 err_out_exit_init:
 965         return retval;
 966 }
 967
 968 static void w1_fini(void)
 969 {
 970         struct w1_master *dev;
 971
 972         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 973                 __w1_remove_master_device(dev);
 974
 975         w1_fini_netlink();
 976
 977         kthread_stop(w1_control_thread);
 978
 979         driver_unregister(&w1_slave_driver);
 980         driver_unregister(&w1_master_driver);
 981         bus_unregister(&w1_bus_type);
 982 }
 983
 984 module_init(w1_init);
 985 module_exit(w1_fini);