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 static struct device_driver w1_slave_driver = {
 218         .name = "w1_slave_driver",
 219         .bus = &w1_bus_type,
 220 };
 221
 222 #if 0
 223 struct device w1_slave_device = {
 224         .parent = NULL,
 225         .bus = &w1_bus_type,
 226         .bus_id = "w1 bus slave",
 227         .driver = &w1_slave_driver,
 228         .release = &w1_slave_release
 229 };
 230 #endif  /*  0  */
 231
 232 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 233 {
 234         struct w1_master *md = dev_to_w1_master(dev);
 235         ssize_t count;
 236
 237         mutex_lock(&md->mutex);
 238         count = sprintf(buf, "%s\n", md->name);
 239         mutex_unlock(&md->mutex);
 240
 241         return count;
 242 }
 243
 244 static ssize_t w1_master_attribute_store_search(struct device * dev,
 245                                                 struct device_attribute *attr,
 246                                                 const char * buf, size_t count)
 247 {
 248         struct w1_master *md = dev_to_w1_master(dev);
 249
 250         mutex_lock(&md->mutex);
 251         md->search_count = simple_strtol(buf, NULL, 0);
 252         mutex_unlock(&md->mutex);
 253
 254         return count;
 255 }
 256
 257 static ssize_t w1_master_attribute_show_search(struct device *dev,
 258                                                struct device_attribute *attr,
 259                                                char *buf)
 260 {
 261         struct w1_master *md = dev_to_w1_master(dev);
 262         ssize_t count;
 263
 264         mutex_lock(&md->mutex);
 265         count = sprintf(buf, "%d\n", md->search_count);
 266         mutex_unlock(&md->mutex);
 267
 268         return count;
 269 }
 270
 271 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 272 {
 273         struct w1_master *md = dev_to_w1_master(dev);
 274         ssize_t count;
 275
 276         mutex_lock(&md->mutex);
 277         count = sprintf(buf, "0x%p\n", md->bus_master);
 278         mutex_unlock(&md->mutex);
 279         return count;
 280 }
 281
 282 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 283 {
 284         ssize_t count;
 285         count = sprintf(buf, "%d\n", w1_timeout);
 286         return count;
 287 }
 288
 289 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 290 {
 291         struct w1_master *md = dev_to_w1_master(dev);
 292         ssize_t count;
 293
 294         mutex_lock(&md->mutex);
 295         count = sprintf(buf, "%d\n", md->max_slave_count);
 296         mutex_unlock(&md->mutex);
 297         return count;
 298 }
 299
 300 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 301 {
 302         struct w1_master *md = dev_to_w1_master(dev);
 303         ssize_t count;
 304
 305         mutex_lock(&md->mutex);
 306         count = sprintf(buf, "%lu\n", md->attempts);
 307         mutex_unlock(&md->mutex);
 308         return count;
 309 }
 310
 311 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 312 {
 313         struct w1_master *md = dev_to_w1_master(dev);
 314         ssize_t count;
 315
 316         mutex_lock(&md->mutex);
 317         count = sprintf(buf, "%d\n", md->slave_count);
 318         mutex_unlock(&md->mutex);
 319         return count;
 320 }
 321
 322 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 323 {
 324         struct w1_master *md = dev_to_w1_master(dev);
 325         int c = PAGE_SIZE;
 326
 327         mutex_lock(&md->mutex);
 328
 329         if (md->slave_count == 0)
 330                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 331         else {
 332                 struct list_head *ent, *n;
 333                 struct w1_slave *sl;
 334
 335                 list_for_each_safe(ent, n, &md->slist) {
 336                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 337
 338                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 339                 }
 340         }
 341
 342         mutex_unlock(&md->mutex);
 343
 344         return PAGE_SIZE - c;
 345 }
 346
 347 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 348         struct device_attribute w1_master_attribute_##_name =   \
 349                 __ATTR(w1_master_##_name, _mode,                \
 350                        w1_master_attribute_show_##_name, NULL)
 351
 352 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 353         struct device_attribute w1_master_attribute_##_name =   \
 354                 __ATTR(w1_master_##_name, _mode,                \
 355                        w1_master_attribute_show_##_name,        \
 356                        w1_master_attribute_store_##_name)
 357
 358 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 359 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 360 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 361 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 362 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 363 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 364 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 365 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 366
 367 static struct attribute *w1_master_default_attrs[] = {
 368         &w1_master_attribute_name.attr,
 369         &w1_master_attribute_slaves.attr,
 370         &w1_master_attribute_slave_count.attr,
 371         &w1_master_attribute_max_slave_count.attr,
 372         &w1_master_attribute_attempts.attr,
 373         &w1_master_attribute_timeout.attr,
 374         &w1_master_attribute_pointer.attr,
 375         &w1_master_attribute_search.attr,
 376         NULL
 377 };
 378
 379 static struct attribute_group w1_master_defattr_group = {
 380         .attrs = w1_master_default_attrs,
 381 };
 382
 383 int w1_create_master_attributes(struct w1_master *master)
 384 {
 385         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 386 }
 387
 388 static void w1_destroy_master_attributes(struct w1_master *master)
 389 {
 390         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 391 }
 392
 393 #ifdef CONFIG_HOTPLUG
 394 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 395                         char *buffer, int buffer_size)
 396 {
 397         struct w1_master *md = NULL;
 398         struct w1_slave *sl = NULL;
 399         char *event_owner, *name;
 400         int err, cur_index=0, cur_len=0;
 401
 402         if (dev->driver == &w1_master_driver) {
 403                 md = container_of(dev, struct w1_master, dev);
 404                 event_owner = "master";
 405                 name = md->name;
 406         } else if (dev->driver == &w1_slave_driver) {
 407                 sl = container_of(dev, struct w1_slave, dev);
 408                 event_owner = "slave";
 409                 name = sl->name;
 410         } else {
 411                 dev_dbg(dev, "Unknown event.\n");
 412                 return -EINVAL;
 413         }
 414
 415         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 416                         event_owner, name, dev->bus_id);
 417
 418         if (dev->driver != &w1_slave_driver || !sl)
 419                 return 0;
 420
 421         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 422                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
 423         if (err)
 424                 return err;
 425
 426         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 427                         &cur_len, "W1_SLAVE_ID=%024LX",
 428                         (unsigned long long)sl->reg_num.id);
 429         if (err)
 430                 return err;
 431
 432         return 0;
 433 };
 434 #else
 435 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 436                         char *buffer, int buffer_size)
 437 {
 438         return 0;
 439 }
 440 #endif
 441
 442 static int __w1_attach_slave_device(struct w1_slave *sl)
 443 {
 444         int err;
 445
 446         sl->dev.parent = &sl->master->dev;
 447         sl->dev.driver = &w1_slave_driver;
 448         sl->dev.bus = &w1_bus_type;
 449         sl->dev.release = &w1_slave_release;
 450
 451         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 452                  "%02x-%012llx",
 453                  (unsigned int) sl->reg_num.family,
 454                  (unsigned long long) sl->reg_num.id);
 455         snprintf(&sl->name[0], sizeof(sl->name),
 456                  "%02x-%012llx",
 457                  (unsigned int) sl->reg_num.family,
 458                  (unsigned long long) sl->reg_num.id);
 459
 460         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 461                 &sl->dev.bus_id[0]);
 462
 463         err = device_register(&sl->dev);
 464         if (err < 0) {
 465                 dev_err(&sl->dev,
 466                         "Device registration [%s] failed. err=%d\n",
 467                         sl->dev.bus_id, err);
 468                 return err;
 469         }
 470
 471         /* Create "name" entry */
 472         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 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_unreg;
 478         }
 479
 480         /* Create "id" entry */
 481         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 482         if (err < 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_rem1;
 487         }
 488
 489         /* if the family driver needs to initialize something... */
 490         if (sl->family->fops && sl->family->fops->add_slave &&
 491             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 492                 dev_err(&sl->dev,
 493                         "sysfs file creation for [%s] failed. err=%d\n",
 494                         sl->dev.bus_id, err);
 495                 goto out_rem2;
 496         }
 497
 498         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 499
 500         return 0;
 501
 502 out_rem2:
 503         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 504 out_rem1:
 505         device_remove_file(&sl->dev, &w1_slave_attr_name);
 506 out_unreg:
 507         device_unregister(&sl->dev);
 508         return err;
 509 }
 510
 511 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 512 {
 513         struct w1_slave *sl;
 514         struct w1_family *f;
 515         int err;
 516         struct w1_netlink_msg msg;
 517
 518         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 519         if (!sl) {
 520                 dev_err(&dev->dev,
 521                          "%s: failed to allocate new slave device.\n",
 522                          __func__);
 523                 return -ENOMEM;
 524         }
 525
 526         memset(sl, 0, sizeof(*sl));
 527
 528         sl->owner = THIS_MODULE;
 529         sl->master = dev;
 530         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 531
 532         memset(&msg, 0, sizeof(msg));
 533         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 534         atomic_set(&sl->refcnt, 0);
 535         init_completion(&sl->released);
 536
 537         spin_lock(&w1_flock);
 538         f = w1_family_registered(rn->family);
 539         if (!f) {
 540                 f= &w1_default_family;
 541                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 542                           rn->family, rn->family,
 543                           (unsigned long long)rn->id, rn->crc);
 544         }
 545         __w1_family_get(f);
 546         spin_unlock(&w1_flock);
 547
 548         sl->family = f;
 549
 550
 551         err = __w1_attach_slave_device(sl);
 552         if (err < 0) {
 553                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 554                          sl->name);
 555                 w1_family_put(sl->family);
 556                 kfree(sl);
 557                 return err;
 558         }
 559
 560         sl->ttl = dev->slave_ttl;
 561         dev->slave_count++;
 562
 563         memcpy(msg.id.id, rn, sizeof(msg.id));
 564         msg.type = W1_SLAVE_ADD;
 565         w1_netlink_send(dev, &msg);
 566
 567         return 0;
 568 }
 569
 570 static void w1_slave_detach(struct w1_slave *sl)
 571 {
 572         struct w1_netlink_msg msg;
 573
 574         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 575
 576         list_del(&sl->w1_slave_entry);
 577
 578         if (sl->family->fops && sl->family->fops->remove_slave)
 579                 sl->family->fops->remove_slave(sl);
 580
 581         memset(&msg, 0, sizeof(msg));
 582         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 583         msg.type = W1_SLAVE_REMOVE;
 584         w1_netlink_send(sl->master, &msg);
 585
 586         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 587         device_remove_file(&sl->dev, &w1_slave_attr_name);
 588         device_unregister(&sl->dev);
 589
 590         wait_for_completion(&sl->released);
 591         kfree(sl);
 592 }
 593
 594 static struct w1_master *w1_search_master(void *data)
 595 {
 596         struct w1_master *dev;
 597         int found = 0;
 598
 599         mutex_lock(&w1_mlock);
 600         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 601                 if (dev->bus_master->data == data) {
 602                         found = 1;
 603                         atomic_inc(&dev->refcnt);
 604                         break;
 605                 }
 606         }
 607         mutex_unlock(&w1_mlock);
 608
 609         return (found)?dev:NULL;
 610 }
 611
 612 struct w1_master *w1_search_master_id(u32 id)
 613 {
 614         struct w1_master *dev;
 615         int found = 0;
 616
 617         mutex_lock(&w1_mlock);
 618         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 619                 if (dev->id == id) {
 620                         found = 1;
 621                         atomic_inc(&dev->refcnt);
 622                         break;
 623                 }
 624         }
 625         mutex_unlock(&w1_mlock);
 626
 627         return (found)?dev:NULL;
 628 }
 629
 630 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 631 {
 632         struct w1_master *dev;
 633         struct w1_slave *sl = NULL;
 634         int found = 0;
 635
 636         mutex_lock(&w1_mlock);
 637         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 638                 mutex_lock(&dev->mutex);
 639                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 640                         if (sl->reg_num.family == id->family &&
 641                                         sl->reg_num.id == id->id &&
 642                                         sl->reg_num.crc == id->crc) {
 643                                 found = 1;
 644                                 atomic_inc(&dev->refcnt);
 645                                 atomic_inc(&sl->refcnt);
 646                                 break;
 647                         }
 648                 }
 649                 mutex_unlock(&dev->mutex);
 650
 651                 if (found)
 652                         break;
 653         }
 654         mutex_unlock(&w1_mlock);
 655
 656         return (found)?sl:NULL;
 657 }
 658
 659 void w1_reconnect_slaves(struct w1_family *f)
 660 {
 661         struct w1_master *dev;
 662
 663         mutex_lock(&w1_mlock);
 664         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 665                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 666                                 dev->name, f->fid);
 667                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 668         }
 669         mutex_unlock(&w1_mlock);
 670 }
 671
 672 static void w1_slave_found(void *data, u64 rn)
 673 {
 674         int slave_count;
 675         struct w1_slave *sl;
 676         struct list_head *ent;
 677         struct w1_reg_num *tmp;
 678         int family_found = 0;
 679         struct w1_master *dev;
 680         u64 rn_le = cpu_to_le64(rn);
 681
 682         dev = w1_search_master(data);
 683         if (!dev) {
 684                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 685                        "it is impossible.\n", data);
 686                 return;
 687         }
 688
 689         tmp = (struct w1_reg_num *) &rn;
 690
 691         slave_count = 0;
 692         list_for_each(ent, &dev->slist) {
 693
 694                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 695
 696                 if (sl->reg_num.family == tmp->family &&
 697                     sl->reg_num.id == tmp->id &&
 698                     sl->reg_num.crc == tmp->crc) {
 699                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 700                         break;
 701                 } else if (sl->reg_num.family == tmp->family) {
 702                         family_found = 1;
 703                         break;
 704                 }
 705
 706                 slave_count++;
 707         }
 708
 709         if (slave_count == dev->slave_count &&
 710                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 711                 w1_attach_slave_device(dev, tmp);
 712         }
 713
 714         atomic_dec(&dev->refcnt);
 715 }
 716
 717 /**
 718  * Performs a ROM Search & registers any devices found.
 719  * The 1-wire search is a simple binary tree search.
 720  * For each bit of the address, we read two bits and write one bit.
 721  * The bit written will put to sleep all devies that don't match that bit.
 722  * When the two reads differ, the direction choice is obvious.
 723  * When both bits are 0, we must choose a path to take.
 724  * When we can scan all 64 bits without having to choose a path, we are done.
 725  *
 726  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 727  *
 728  * @dev        The master device to search
 729  * @cb         Function to call when a device is found
 730  */
 731 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 732 {
 733         u64 last_rn, rn, tmp64;
 734         int i, slave_count = 0;
 735         int last_zero, last_device;
 736         int search_bit, desc_bit;
 737         u8  triplet_ret = 0;
 738
 739         search_bit = 0;
 740         rn = last_rn = 0;
 741         last_device = 0;
 742         last_zero = -1;
 743
 744         desc_bit = 64;
 745
 746         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 747                 last_rn = rn;
 748                 rn = 0;
 749
 750                 /*
 751                  * Reset bus and all 1-wire device state machines
 752                  * so they can respond to our requests.
 753                  *
 754                  * Return 0 - device(s) present, 1 - no devices present.
 755                  */
 756                 if (w1_reset_bus(dev)) {
 757                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 758                         break;
 759                 }
 760
 761                 /* Start the search */
 762                 w1_write_8(dev, search_type);
 763                 for (i = 0; i < 64; ++i) {
 764                         /* Determine the direction/search bit */
 765                         if (i == desc_bit)
 766                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 767                         else if (i > desc_bit)
 768                                 search_bit = 0;   /* take the 0 path on the next branch */
 769                         else
 770                                 search_bit = ((last_rn >> i) & 0x1);
 771
 772                         /** Read two bits and write one bit */
 773                         triplet_ret = w1_triplet(dev, search_bit);
 774
 775                         /* quit if no device responded */
 776                         if ( (triplet_ret & 0x03) == 0x03 )
 777                                 break;
 778
 779                         /* If both directions were valid, and we took the 0 path... */
 780                         if (triplet_ret == 0)
 781                                 last_zero = i;
 782
 783                         /* extract the direction taken & update the device number */
 784                         tmp64 = (triplet_ret >> 2);
 785                         rn |= (tmp64 << i);
 786                 }
 787
 788                 if ( (triplet_ret & 0x03) != 0x03 ) {
 789                         if ( (desc_bit == last_zero) || (last_zero < 0))
 790                                 last_device = 1;
 791                         desc_bit = last_zero;
 792                         cb(dev->bus_master->data, rn);
 793                 }
 794         }
 795 }
 796
 797 static int w1_control(void *data)
 798 {
 799         struct w1_slave *sl, *sln;
 800         struct w1_master *dev, *n;
 801         int have_to_wait = 0;
 802
 803         while (!kthread_should_stop() || have_to_wait) {
 804                 have_to_wait = 0;
 805
 806                 try_to_freeze();
 807                 msleep_interruptible(w1_control_timeout * 1000);
 808
 809                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 810                         if (!kthread_should_stop() && !dev->flags)
 811                                 continue;
 812                         /*
 813                          * Little race: we can create thread but not set the flag.
 814                          * Get a chance for external process to set flag up.
 815                          */
 816                         if (!dev->initialized) {
 817                                 have_to_wait = 1;
 818                                 continue;
 819                         }
 820
 821                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 822                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 823
 824                                 mutex_lock(&w1_mlock);
 825                                 list_del(&dev->w1_master_entry);
 826                                 mutex_unlock(&w1_mlock);
 827
 828                                 mutex_lock(&dev->mutex);
 829                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 830                                         w1_slave_detach(sl);
 831                                 }
 832                                 w1_destroy_master_attributes(dev);
 833                                 mutex_unlock(&dev->mutex);
 834                                 atomic_dec(&dev->refcnt);
 835                                 continue;
 836                         }
 837
 838                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 839                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 840                                 mutex_lock(&dev->mutex);
 841                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 842                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 843                                                 struct w1_reg_num rn;
 844
 845                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 846                                                 w1_slave_detach(sl);
 847
 848                                                 w1_attach_slave_device(dev, &rn);
 849                                         }
 850                                 }
 851                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 852                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 853                                 mutex_unlock(&dev->mutex);
 854                         }
 855                 }
 856         }
 857
 858         return 0;
 859 }
 860
 861 void w1_search_process(struct w1_master *dev, u8 search_type)
 862 {
 863         struct w1_slave *sl, *sln;
 864
 865         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 866                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 867
 868         w1_search_devices(dev, search_type, w1_slave_found);
 869
 870         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 871                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 872                         w1_slave_detach(sl);
 873
 874                         dev->slave_count--;
 875                 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 876                         sl->ttl = dev->slave_ttl;
 877         }
 878
 879         if (dev->search_count > 0)
 880                 dev->search_count--;
 881 }
 882
 883 int w1_process(void *data)
 884 {
 885         struct w1_master *dev = (struct w1_master *) data;
 886
 887         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 888                 try_to_freeze();
 889                 msleep_interruptible(w1_timeout * 1000);
 890
 891                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 892                         break;
 893
 894                 if (!dev->initialized)
 895                         continue;
 896
 897                 if (dev->search_count == 0)
 898                         continue;
 899
 900                 mutex_lock(&dev->mutex);
 901                 w1_search_process(dev, W1_SEARCH);
 902                 mutex_unlock(&dev->mutex);
 903         }
 904
 905         atomic_dec(&dev->refcnt);
 906
 907         return 0;
 908 }
 909
 910 static int w1_init(void)
 911 {
 912         int retval;
 913
 914         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 915
 916         w1_init_netlink();
 917
 918         retval = bus_register(&w1_bus_type);
 919         if (retval) {
 920                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 921                 goto err_out_exit_init;
 922         }
 923
 924         retval = driver_register(&w1_master_driver);
 925         if (retval) {
 926                 printk(KERN_ERR
 927                         "Failed to register master driver. err=%d.\n",
 928                         retval);
 929                 goto err_out_bus_unregister;
 930         }
 931
 932         retval = driver_register(&w1_slave_driver);
 933         if (retval) {
 934                 printk(KERN_ERR
 935                         "Failed to register master driver. err=%d.\n",
 936                         retval);
 937                 goto err_out_master_unregister;
 938         }
 939
 940         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 941         if (IS_ERR(w1_control_thread)) {
 942                 retval = PTR_ERR(w1_control_thread);
 943                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 944                         retval);
 945                 goto err_out_slave_unregister;
 946         }
 947
 948         return 0;
 949
 950 err_out_slave_unregister:
 951         driver_unregister(&w1_slave_driver);
 952
 953 err_out_master_unregister:
 954         driver_unregister(&w1_master_driver);
 955
 956 err_out_bus_unregister:
 957         bus_unregister(&w1_bus_type);
 958
 959 err_out_exit_init:
 960         return retval;
 961 }
 962
 963 static void w1_fini(void)
 964 {
 965         struct w1_master *dev;
 966
 967         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 968                 __w1_remove_master_device(dev);
 969
 970         w1_fini_netlink();
 971
 972         kthread_stop(w1_control_thread);
 973
 974         driver_unregister(&w1_slave_driver);
 975         driver_unregister(&w1_master_driver);
 976         bus_unregister(&w1_bus_type);
 977 }
 978
 979 module_init(w1_init);
 980 module_exit(w1_fini);