drivers/w1/w1.c

   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33 #include <linux/kthread.h>
  34
  35 #include <asm/atomic.h>
  36
  37 #include "w1.h"
  38 #include "w1_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 static int w1_control_timeout = 1;
  49 int w1_max_slave_count = 10;
  50 int w1_max_slave_ttl = 10;
  51
  52 module_param_named(timeout, w1_timeout, int, 0);
  53 module_param_named(control_timeout, w1_control_timeout, int, 0);
  54 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  55 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  56
  57 DEFINE_MUTEX(w1_mlock);
  58 LIST_HEAD(w1_masters);
  59
  60 static struct task_struct *w1_control_thread;
  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 void w1_master_release(struct device *dev)
  73 {
  74         struct w1_master *md = dev_to_w1_master(dev);
  75
  76         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  77         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  78         kfree(md);
  79 }
  80
  81 static void w1_slave_release(struct device *dev)
  82 {
  83         struct w1_slave *sl = dev_to_w1_slave(dev);
  84
  85         printk("%s: Releasing %s.\n", __func__, sl->name);
  86
  87         while (atomic_read(&sl->refcnt)) {
  88                 printk("Waiting for %s to become free: refcnt=%d.\n",
  89                                 sl->name, atomic_read(&sl->refcnt));
  90                 if (msleep_interruptible(1000))
  91                         flush_signals(current);
  92         }
  93
  94         w1_family_put(sl->family);
  95         sl->master->slave_count--;
  96
  97         complete(&sl->released);
  98 }
  99
 100 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 101 {
 102         struct w1_slave *sl = dev_to_w1_slave(dev);
 103
 104         return sprintf(buf, "%s\n", sl->name);
 105 }
 106
 107 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
 108 {
 109         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 110
 111         if (off > 8) {
 112                 count = 0;
 113         } else {
 114                 if (off + count > 8)
 115                         count = 8 - off;
 116
 117                 memcpy(buf, (u8 *)&sl->reg_num, count);
 118         }
 119
 120         return count;
 121 }
 122
 123 static struct device_attribute w1_slave_attr_name =
 124         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 125
 126 static struct bin_attribute w1_slave_attr_bin_id = {
 127       .attr = {
 128               .name = "id",
 129               .mode = S_IRUGO,
 130               .owner = THIS_MODULE,
 131       },
 132       .size = 8,
 133       .read = w1_slave_read_id,
 134 };
 135
 136 /* Default family */
 137
 138 static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
 139 {
 140         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 141
 142         mutex_lock(&sl->master->mutex);
 143         if (w1_reset_select_slave(sl)) {
 144                 count = 0;
 145                 goto out_up;
 146         }
 147
 148         w1_write_block(sl->master, buf, count);
 149
 150 out_up:
 151         mutex_unlock(&sl->master->mutex);
 152         return count;
 153 }
 154
 155 static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
 156 {
 157         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 158
 159         mutex_lock(&sl->master->mutex);
 160         w1_read_block(sl->master, buf, count);
 161         mutex_unlock(&sl->master->mutex);
 162         return count;
 163 }
 164
 165 static struct bin_attribute w1_default_attr = {
 166       .attr = {
 167               .name = "rw",
 168               .mode = S_IRUGO | S_IWUSR,
 169               .owner = THIS_MODULE,
 170       },
 171       .size = PAGE_SIZE,
 172       .read = w1_default_read,
 173       .write = w1_default_write,
 174 };
 175
 176 static int w1_default_add_slave(struct w1_slave *sl)
 177 {
 178         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 179 }
 180
 181 static void w1_default_remove_slave(struct w1_slave *sl)
 182 {
 183         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 184 }
 185
 186 static struct w1_family_ops w1_default_fops = {
 187         .add_slave      = w1_default_add_slave,
 188         .remove_slave   = w1_default_remove_slave,
 189 };
 190
 191 static struct w1_family w1_default_family = {
 192         .fops = &w1_default_fops,
 193 };
 194
 195 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 196
 197 static struct bus_type w1_bus_type = {
 198         .name = "w1",
 199         .match = w1_master_match,
 200         .uevent = w1_uevent,
 201 };
 202
 203 struct device_driver w1_master_driver = {
 204         .name = "w1_master_driver",
 205         .bus = &w1_bus_type,
 206         .probe = w1_master_probe,
 207 };
 208
 209 struct device w1_master_device = {
 210         .parent = NULL,
 211         .bus = &w1_bus_type,
 212         .bus_id = "w1 bus master",
 213         .driver = &w1_master_driver,
 214         .release = &w1_master_release
 215 };
 216
 217 struct device_driver w1_slave_driver = {
 218         .name = "w1_slave_driver",
 219         .bus = &w1_bus_type,
 220 };
 221
 222 struct device w1_slave_device = {
 223         .parent = NULL,
 224         .bus = &w1_bus_type,
 225         .bus_id = "w1 bus slave",
 226         .driver = &w1_slave_driver,
 227         .release = &w1_slave_release
 228 };
 229
 230 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 231 {
 232         struct w1_master *md = dev_to_w1_master(dev);
 233         ssize_t count;
 234
 235         mutex_lock(&md->mutex);
 236         count = sprintf(buf, "%s\n", md->name);
 237         mutex_unlock(&md->mutex);
 238
 239         return count;
 240 }
 241
 242 static ssize_t w1_master_attribute_store_search(struct device * dev,
 243                                                 struct device_attribute *attr,
 244                                                 const char * buf, size_t count)
 245 {
 246         struct w1_master *md = dev_to_w1_master(dev);
 247
 248         mutex_lock(&md->mutex);
 249         md->search_count = simple_strtol(buf, NULL, 0);
 250         mutex_unlock(&md->mutex);
 251
 252         return count;
 253 }
 254
 255 static ssize_t w1_master_attribute_show_search(struct device *dev,
 256                                                struct device_attribute *attr,
 257                                                char *buf)
 258 {
 259         struct w1_master *md = dev_to_w1_master(dev);
 260         ssize_t count;
 261
 262         mutex_lock(&md->mutex);
 263         count = sprintf(buf, "%d\n", md->search_count);
 264         mutex_unlock(&md->mutex);
 265
 266         return count;
 267 }
 268
 269 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 270 {
 271         struct w1_master *md = dev_to_w1_master(dev);
 272         ssize_t count;
 273
 274         mutex_lock(&md->mutex);
 275         count = sprintf(buf, "0x%p\n", md->bus_master);
 276         mutex_unlock(&md->mutex);
 277         return count;
 278 }
 279
 280 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 281 {
 282         ssize_t count;
 283         count = sprintf(buf, "%d\n", w1_timeout);
 284         return count;
 285 }
 286
 287 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 288 {
 289         struct w1_master *md = dev_to_w1_master(dev);
 290         ssize_t count;
 291
 292         mutex_lock(&md->mutex);
 293         count = sprintf(buf, "%d\n", md->max_slave_count);
 294         mutex_unlock(&md->mutex);
 295         return count;
 296 }
 297
 298 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 299 {
 300         struct w1_master *md = dev_to_w1_master(dev);
 301         ssize_t count;
 302
 303         mutex_lock(&md->mutex);
 304         count = sprintf(buf, "%lu\n", md->attempts);
 305         mutex_unlock(&md->mutex);
 306         return count;
 307 }
 308
 309 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 310 {
 311         struct w1_master *md = dev_to_w1_master(dev);
 312         ssize_t count;
 313
 314         mutex_lock(&md->mutex);
 315         count = sprintf(buf, "%d\n", md->slave_count);
 316         mutex_unlock(&md->mutex);
 317         return count;
 318 }
 319
 320 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 321 {
 322         struct w1_master *md = dev_to_w1_master(dev);
 323         int c = PAGE_SIZE;
 324
 325         mutex_lock(&md->mutex);
 326
 327         if (md->slave_count == 0)
 328                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 329         else {
 330                 struct list_head *ent, *n;
 331                 struct w1_slave *sl;
 332
 333                 list_for_each_safe(ent, n, &md->slist) {
 334                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 335
 336                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 337                 }
 338         }
 339
 340         mutex_unlock(&md->mutex);
 341
 342         return PAGE_SIZE - c;
 343 }
 344
 345 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 346         struct device_attribute w1_master_attribute_##_name =   \
 347                 __ATTR(w1_master_##_name, _mode,                \
 348                        w1_master_attribute_show_##_name, NULL)
 349
 350 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 351         struct device_attribute w1_master_attribute_##_name =   \
 352                 __ATTR(w1_master_##_name, _mode,                \
 353                        w1_master_attribute_show_##_name,        \
 354                        w1_master_attribute_store_##_name)
 355
 356 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 357 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 358 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 359 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 360 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 361 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 362 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 363 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 364
 365 static struct attribute *w1_master_default_attrs[] = {
 366         &w1_master_attribute_name.attr,
 367         &w1_master_attribute_slaves.attr,
 368         &w1_master_attribute_slave_count.attr,
 369         &w1_master_attribute_max_slave_count.attr,
 370         &w1_master_attribute_attempts.attr,
 371         &w1_master_attribute_timeout.attr,
 372         &w1_master_attribute_pointer.attr,
 373         &w1_master_attribute_search.attr,
 374         NULL
 375 };
 376
 377 static struct attribute_group w1_master_defattr_group = {
 378         .attrs = w1_master_default_attrs,
 379 };
 380
 381 int w1_create_master_attributes(struct w1_master *master)
 382 {
 383         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 384 }
 385
 386 void w1_destroy_master_attributes(struct w1_master *master)
 387 {
 388         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 389 }
 390
 391 #ifdef CONFIG_HOTPLUG
 392 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 393 {
 394         struct w1_master *md = NULL;
 395         struct w1_slave *sl = NULL;
 396         char *event_owner, *name;
 397         int err, cur_index=0, cur_len=0;
 398
 399         if (dev->driver == &w1_master_driver) {
 400                 md = container_of(dev, struct w1_master, dev);
 401                 event_owner = "master";
 402                 name = md->name;
 403         } else if (dev->driver == &w1_slave_driver) {
 404                 sl = container_of(dev, struct w1_slave, dev);
 405                 event_owner = "slave";
 406                 name = sl->name;
 407         } else {
 408                 dev_dbg(dev, "Unknown event.\n");
 409                 return -EINVAL;
 410         }
 411
 412         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
 413
 414         if (dev->driver != &w1_slave_driver || !sl)
 415                 return 0;
 416
 417         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
 418         if (err)
 419                 return err;
 420
 421         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
 422         if (err)
 423                 return err;
 424
 425         return 0;
 426 };
 427 #else
 428 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 429 {
 430         return 0;
 431 }
 432 #endif
 433
 434 static int __w1_attach_slave_device(struct w1_slave *sl)
 435 {
 436         int err;
 437
 438         sl->dev.parent = &sl->master->dev;
 439         sl->dev.driver = &w1_slave_driver;
 440         sl->dev.bus = &w1_bus_type;
 441         sl->dev.release = &w1_slave_release;
 442
 443         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 444                  "%02x-%012llx",
 445                  (unsigned int) sl->reg_num.family,
 446                  (unsigned long long) sl->reg_num.id);
 447         snprintf(&sl->name[0], sizeof(sl->name),
 448                  "%02x-%012llx",
 449                  (unsigned int) sl->reg_num.family,
 450                  (unsigned long long) sl->reg_num.id);
 451
 452         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
 453
 454         err = device_register(&sl->dev);
 455         if (err < 0) {
 456                 dev_err(&sl->dev,
 457                         "Device registration [%s] failed. err=%d\n",
 458                         sl->dev.bus_id, err);
 459                 return err;
 460         }
 461
 462         /* Create "name" entry */
 463         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 464         if (err < 0) {
 465                 dev_err(&sl->dev,
 466                         "sysfs file creation for [%s] failed. err=%d\n",
 467                         sl->dev.bus_id, err);
 468                 goto out_unreg;
 469         }
 470
 471         /* Create "id" entry */
 472         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 473         if (err < 0) {
 474                 dev_err(&sl->dev,
 475                         "sysfs file creation for [%s] failed. err=%d\n",
 476                         sl->dev.bus_id, err);
 477                 goto out_rem1;
 478         }
 479
 480         /* if the family driver needs to initialize something... */
 481         if (sl->family->fops && sl->family->fops->add_slave &&
 482             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 483                 dev_err(&sl->dev,
 484                         "sysfs file creation for [%s] failed. err=%d\n",
 485                         sl->dev.bus_id, err);
 486                 goto out_rem2;
 487         }
 488
 489         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 490
 491         return 0;
 492
 493 out_rem2:
 494         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 495 out_rem1:
 496         device_remove_file(&sl->dev, &w1_slave_attr_name);
 497 out_unreg:
 498         device_unregister(&sl->dev);
 499         return err;
 500 }
 501
 502 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 503 {
 504         struct w1_slave *sl;
 505         struct w1_family *f;
 506         int err;
 507         struct w1_netlink_msg msg;
 508
 509         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 510         if (!sl) {
 511                 dev_err(&dev->dev,
 512                          "%s: failed to allocate new slave device.\n",
 513                          __func__);
 514                 return -ENOMEM;
 515         }
 516
 517         memset(sl, 0, sizeof(*sl));
 518
 519         sl->owner = THIS_MODULE;
 520         sl->master = dev;
 521         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 522
 523         memset(&msg, 0, sizeof(msg));
 524         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 525         atomic_set(&sl->refcnt, 0);
 526         init_completion(&sl->released);
 527
 528         spin_lock(&w1_flock);
 529         f = w1_family_registered(rn->family);
 530         if (!f) {
 531                 f= &w1_default_family;
 532                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 533                           rn->family, rn->family,
 534                           (unsigned long long)rn->id, rn->crc);
 535         }
 536         __w1_family_get(f);
 537         spin_unlock(&w1_flock);
 538
 539         sl->family = f;
 540
 541
 542         err = __w1_attach_slave_device(sl);
 543         if (err < 0) {
 544                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 545                          sl->name);
 546                 w1_family_put(sl->family);
 547                 kfree(sl);
 548                 return err;
 549         }
 550
 551         sl->ttl = dev->slave_ttl;
 552         dev->slave_count++;
 553
 554         memcpy(msg.id.id, rn, sizeof(msg.id));
 555         msg.type = W1_SLAVE_ADD;
 556         w1_netlink_send(dev, &msg);
 557
 558         return 0;
 559 }
 560
 561 static void w1_slave_detach(struct w1_slave *sl)
 562 {
 563         struct w1_netlink_msg msg;
 564
 565         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 566
 567         list_del(&sl->w1_slave_entry);
 568
 569         if (sl->family->fops && sl->family->fops->remove_slave)
 570                 sl->family->fops->remove_slave(sl);
 571
 572         memset(&msg, 0, sizeof(msg));
 573         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 574         msg.type = W1_SLAVE_REMOVE;
 575         w1_netlink_send(sl->master, &msg);
 576
 577         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 578         device_remove_file(&sl->dev, &w1_slave_attr_name);
 579         device_unregister(&sl->dev);
 580
 581         wait_for_completion(&sl->released);
 582         kfree(sl);
 583 }
 584
 585 static struct w1_master *w1_search_master(void *data)
 586 {
 587         struct w1_master *dev;
 588         int found = 0;
 589
 590         mutex_lock(&w1_mlock);
 591         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 592                 if (dev->bus_master->data == data) {
 593                         found = 1;
 594                         atomic_inc(&dev->refcnt);
 595                         break;
 596                 }
 597         }
 598         mutex_unlock(&w1_mlock);
 599
 600         return (found)?dev:NULL;
 601 }
 602
 603 struct w1_master *w1_search_master_id(u32 id)
 604 {
 605         struct w1_master *dev;
 606         int found = 0;
 607
 608         mutex_lock(&w1_mlock);
 609         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 610                 if (dev->id == id) {
 611                         found = 1;
 612                         atomic_inc(&dev->refcnt);
 613                         break;
 614                 }
 615         }
 616         mutex_unlock(&w1_mlock);
 617
 618         return (found)?dev:NULL;
 619 }
 620
 621 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 622 {
 623         struct w1_master *dev;
 624         struct w1_slave *sl = NULL;
 625         int found = 0;
 626
 627         mutex_lock(&w1_mlock);
 628         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 629                 mutex_lock(&dev->mutex);
 630                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 631                         if (sl->reg_num.family == id->family &&
 632                                         sl->reg_num.id == id->id &&
 633                                         sl->reg_num.crc == id->crc) {
 634                                 found = 1;
 635                                 atomic_inc(&dev->refcnt);
 636                                 atomic_inc(&sl->refcnt);
 637                                 break;
 638                         }
 639                 }
 640                 mutex_unlock(&dev->mutex);
 641
 642                 if (found)
 643                         break;
 644         }
 645         mutex_unlock(&w1_mlock);
 646
 647         return (found)?sl:NULL;
 648 }
 649
 650 void w1_reconnect_slaves(struct w1_family *f)
 651 {
 652         struct w1_master *dev;
 653
 654         mutex_lock(&w1_mlock);
 655         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 656                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 657                                 dev->name, f->fid);
 658                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 659         }
 660         mutex_unlock(&w1_mlock);
 661 }
 662
 663 static void w1_slave_found(void *data, u64 rn)
 664 {
 665         int slave_count;
 666         struct w1_slave *sl;
 667         struct list_head *ent;
 668         struct w1_reg_num *tmp;
 669         int family_found = 0;
 670         struct w1_master *dev;
 671         u64 rn_le = cpu_to_le64(rn);
 672
 673         dev = w1_search_master(data);
 674         if (!dev) {
 675                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 676                        "it is impossible.\n", data);
 677                 return;
 678         }
 679
 680         tmp = (struct w1_reg_num *) &rn;
 681
 682         slave_count = 0;
 683         list_for_each(ent, &dev->slist) {
 684
 685                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 686
 687                 if (sl->reg_num.family == tmp->family &&
 688                     sl->reg_num.id == tmp->id &&
 689                     sl->reg_num.crc == tmp->crc) {
 690                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 691                         break;
 692                 } else if (sl->reg_num.family == tmp->family) {
 693                         family_found = 1;
 694                         break;
 695                 }
 696
 697                 slave_count++;
 698         }
 699
 700         if (slave_count == dev->slave_count &&
 701                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 702                 w1_attach_slave_device(dev, tmp);
 703         }
 704
 705         atomic_dec(&dev->refcnt);
 706 }
 707
 708 /**
 709  * Performs a ROM Search & registers any devices found.
 710  * The 1-wire search is a simple binary tree search.
 711  * For each bit of the address, we read two bits and write one bit.
 712  * The bit written will put to sleep all devies that don't match that bit.
 713  * When the two reads differ, the direction choice is obvious.
 714  * When both bits are 0, we must choose a path to take.
 715  * When we can scan all 64 bits without having to choose a path, we are done.
 716  *
 717  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 718  *
 719  * @dev        The master device to search
 720  * @cb         Function to call when a device is found
 721  */
 722 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 723 {
 724         u64 last_rn, rn, tmp64;
 725         int i, slave_count = 0;
 726         int last_zero, last_device;
 727         int search_bit, desc_bit;
 728         u8  triplet_ret = 0;
 729
 730         search_bit = 0;
 731         rn = last_rn = 0;
 732         last_device = 0;
 733         last_zero = -1;
 734
 735         desc_bit = 64;
 736
 737         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 738                 last_rn = rn;
 739                 rn = 0;
 740
 741                 /*
 742                  * Reset bus and all 1-wire device state machines
 743                  * so they can respond to our requests.
 744                  *
 745                  * Return 0 - device(s) present, 1 - no devices present.
 746                  */
 747                 if (w1_reset_bus(dev)) {
 748                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 749                         break;
 750                 }
 751
 752                 /* Start the search */
 753                 w1_write_8(dev, search_type);
 754                 for (i = 0; i < 64; ++i) {
 755                         /* Determine the direction/search bit */
 756                         if (i == desc_bit)
 757                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 758                         else if (i > desc_bit)
 759                                 search_bit = 0;   /* take the 0 path on the next branch */
 760                         else
 761                                 search_bit = ((last_rn >> i) & 0x1);
 762
 763                         /** Read two bits and write one bit */
 764                         triplet_ret = w1_triplet(dev, search_bit);
 765
 766                         /* quit if no device responded */
 767                         if ( (triplet_ret & 0x03) == 0x03 )
 768                                 break;
 769
 770                         /* If both directions were valid, and we took the 0 path... */
 771                         if (triplet_ret == 0)
 772                                 last_zero = i;
 773
 774                         /* extract the direction taken & update the device number */
 775                         tmp64 = (triplet_ret >> 2);
 776                         rn |= (tmp64 << i);
 777                 }
 778
 779                 if ( (triplet_ret & 0x03) != 0x03 ) {
 780                         if ( (desc_bit == last_zero) || (last_zero < 0))
 781                                 last_device = 1;
 782                         desc_bit = last_zero;
 783                         cb(dev->bus_master->data, rn);
 784                 }
 785         }
 786 }
 787
 788 static int w1_control(void *data)
 789 {
 790         struct w1_slave *sl, *sln;
 791         struct w1_master *dev, *n;
 792         int have_to_wait = 0;
 793
 794         while (!kthread_should_stop() || have_to_wait) {
 795                 have_to_wait = 0;
 796
 797                 try_to_freeze();
 798                 msleep_interruptible(w1_control_timeout * 1000);
 799
 800                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 801                         if (!kthread_should_stop() && !dev->flags)
 802                                 continue;
 803                         /*
 804                          * Little race: we can create thread but not set the flag.
 805                          * Get a chance for external process to set flag up.
 806                          */
 807                         if (!dev->initialized) {
 808                                 have_to_wait = 1;
 809                                 continue;
 810                         }
 811
 812                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 813                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 814
 815                                 mutex_lock(&w1_mlock);
 816                                 list_del(&dev->w1_master_entry);
 817                                 mutex_unlock(&w1_mlock);
 818
 819                                 mutex_lock(&dev->mutex);
 820                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 821                                         w1_slave_detach(sl);
 822                                 }
 823                                 w1_destroy_master_attributes(dev);
 824                                 mutex_unlock(&dev->mutex);
 825                                 atomic_dec(&dev->refcnt);
 826                                 continue;
 827                         }
 828
 829                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 830                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 831                                 mutex_lock(&dev->mutex);
 832                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 833                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 834                                                 struct w1_reg_num rn;
 835
 836                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 837                                                 w1_slave_detach(sl);
 838
 839                                                 w1_attach_slave_device(dev, &rn);
 840                                         }
 841                                 }
 842                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 843                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 844                                 mutex_unlock(&dev->mutex);
 845                         }
 846                 }
 847         }
 848
 849         return 0;
 850 }
 851
 852 void w1_search_process(struct w1_master *dev, u8 search_type)
 853 {
 854         struct w1_slave *sl, *sln;
 855
 856         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 857                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 858
 859         w1_search_devices(dev, search_type, w1_slave_found);
 860
 861         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 862                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 863                         w1_slave_detach(sl);
 864
 865                         dev->slave_count--;
 866                 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 867                         sl->ttl = dev->slave_ttl;
 868         }
 869
 870         if (dev->search_count > 0)
 871                 dev->search_count--;
 872 }
 873
 874 int w1_process(void *data)
 875 {
 876         struct w1_master *dev = (struct w1_master *) data;
 877
 878         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 879                 try_to_freeze();
 880                 msleep_interruptible(w1_timeout * 1000);
 881
 882                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 883                         break;
 884
 885                 if (!dev->initialized)
 886                         continue;
 887
 888                 if (dev->search_count == 0)
 889                         continue;
 890
 891                 mutex_lock(&dev->mutex);
 892                 w1_search_process(dev, W1_SEARCH);
 893                 mutex_unlock(&dev->mutex);
 894         }
 895
 896         atomic_dec(&dev->refcnt);
 897
 898         return 0;
 899 }
 900
 901 static int w1_init(void)
 902 {
 903         int retval;
 904
 905         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 906
 907         w1_init_netlink();
 908
 909         retval = bus_register(&w1_bus_type);
 910         if (retval) {
 911                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 912                 goto err_out_exit_init;
 913         }
 914
 915         retval = driver_register(&w1_master_driver);
 916         if (retval) {
 917                 printk(KERN_ERR
 918                         "Failed to register master driver. err=%d.\n",
 919                         retval);
 920                 goto err_out_bus_unregister;
 921         }
 922
 923         retval = driver_register(&w1_slave_driver);
 924         if (retval) {
 925                 printk(KERN_ERR
 926                         "Failed to register master driver. err=%d.\n",
 927                         retval);
 928                 goto err_out_master_unregister;
 929         }
 930
 931         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 932         if (IS_ERR(w1_control_thread)) {
 933                 retval = PTR_ERR(w1_control_thread);
 934                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 935                         retval);
 936                 goto err_out_slave_unregister;
 937         }
 938
 939         return 0;
 940
 941 err_out_slave_unregister:
 942         driver_unregister(&w1_slave_driver);
 943
 944 err_out_master_unregister:
 945         driver_unregister(&w1_master_driver);
 946
 947 err_out_bus_unregister:
 948         bus_unregister(&w1_bus_type);
 949
 950 err_out_exit_init:
 951         return retval;
 952 }
 953
 954 static void w1_fini(void)
 955 {
 956         struct w1_master *dev;
 957
 958         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 959                 __w1_remove_master_device(dev);
 960
 961         w1_fini_netlink();
 962
 963         kthread_stop(w1_control_thread);
 964
 965         driver_unregister(&w1_slave_driver);
 966         driver_unregister(&w1_master_driver);
 967         bus_unregister(&w1_bus_type);
 968 }
 969
 970 module_init(w1_init);
 971 module_exit(w1_fini);