drivers/w1/w1.c

   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33 #include <linux/kthread.h>
  34 #include <linux/freezer.h>
  35
  36 #include <asm/atomic.h>
  37
  38 #include "w1.h"
  39 #include "w1_log.h"
  40 #include "w1_int.h"
  41 #include "w1_family.h"
  42 #include "w1_netlink.h"
  43
  44 MODULE_LICENSE("GPL");
  45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  47
  48 static int w1_timeout = 10;
  49 static int w1_control_timeout = 1;
  50 int w1_max_slave_count = 10;
  51 int w1_max_slave_ttl = 10;
  52
  53 module_param_named(timeout, w1_timeout, int, 0);
  54 module_param_named(control_timeout, w1_control_timeout, int, 0);
  55 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  56 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  57
  58 DEFINE_MUTEX(w1_mlock);
  59 LIST_HEAD(w1_masters);
  60
  61 static struct task_struct *w1_control_thread;
  62
  63 static int w1_master_match(struct device *dev, struct device_driver *drv)
  64 {
  65         return 1;
  66 }
  67
  68 static int w1_master_probe(struct device *dev)
  69 {
  70         return -ENODEV;
  71 }
  72
  73 static void w1_master_release(struct device *dev)
  74 {
  75         struct w1_master *md = dev_to_w1_master(dev);
  76
  77         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  78         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  79         kfree(md);
  80 }
  81
  82 static void w1_slave_release(struct device *dev)
  83 {
  84         struct w1_slave *sl = dev_to_w1_slave(dev);
  85
  86         printk("%s: Releasing %s.\n", __func__, sl->name);
  87
  88         while (atomic_read(&sl->refcnt)) {
  89                 printk("Waiting for %s to become free: refcnt=%d.\n",
  90                                 sl->name, atomic_read(&sl->refcnt));
  91                 if (msleep_interruptible(1000))
  92                         flush_signals(current);
  93         }
  94
  95         w1_family_put(sl->family);
  96         sl->master->slave_count--;
  97
  98         complete(&sl->released);
  99 }
 100
 101 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 102 {
 103         struct w1_slave *sl = dev_to_w1_slave(dev);
 104
 105         return sprintf(buf, "%s\n", sl->name);
 106 }
 107
 108 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
 109 {
 110         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 111
 112         if (off > 8) {
 113                 count = 0;
 114         } else {
 115                 if (off + count > 8)
 116                         count = 8 - off;
 117
 118                 memcpy(buf, (u8 *)&sl->reg_num, count);
 119         }
 120
 121         return count;
 122 }
 123
 124 static struct device_attribute w1_slave_attr_name =
 125         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 126
 127 static struct bin_attribute w1_slave_attr_bin_id = {
 128       .attr = {
 129               .name = "id",
 130               .mode = S_IRUGO,
 131       },
 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       },
 170       .size = PAGE_SIZE,
 171       .read = w1_default_read,
 172       .write = w1_default_write,
 173 };
 174
 175 static int w1_default_add_slave(struct w1_slave *sl)
 176 {
 177         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 178 }
 179
 180 static void w1_default_remove_slave(struct w1_slave *sl)
 181 {
 182         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 183 }
 184
 185 static struct w1_family_ops w1_default_fops = {
 186         .add_slave      = w1_default_add_slave,
 187         .remove_slave   = w1_default_remove_slave,
 188 };
 189
 190 static struct w1_family w1_default_family = {
 191         .fops = &w1_default_fops,
 192 };
 193
 194 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 195
 196 static struct bus_type w1_bus_type = {
 197         .name = "w1",
 198         .match = w1_master_match,
 199         .uevent = w1_uevent,
 200 };
 201
 202 struct device_driver w1_master_driver = {
 203         .name = "w1_master_driver",
 204         .bus = &w1_bus_type,
 205         .probe = w1_master_probe,
 206 };
 207
 208 struct device w1_master_device = {
 209         .parent = NULL,
 210         .bus = &w1_bus_type,
 211         .bus_id = "w1 bus master",
 212         .driver = &w1_master_driver,
 213         .release = &w1_master_release
 214 };
 215
 216 static struct device_driver w1_slave_driver = {
 217         .name = "w1_slave_driver",
 218         .bus = &w1_bus_type,
 219 };
 220
 221 #if 0
 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 #endif  /*  0  */
 230
 231 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 232 {
 233         struct w1_master *md = dev_to_w1_master(dev);
 234         ssize_t count;
 235
 236         mutex_lock(&md->mutex);
 237         count = sprintf(buf, "%s\n", md->name);
 238         mutex_unlock(&md->mutex);
 239
 240         return count;
 241 }
 242
 243 static ssize_t w1_master_attribute_store_search(struct device * dev,
 244                                                 struct device_attribute *attr,
 245                                                 const char * buf, size_t count)
 246 {
 247         struct w1_master *md = dev_to_w1_master(dev);
 248
 249         mutex_lock(&md->mutex);
 250         md->search_count = simple_strtol(buf, NULL, 0);
 251         mutex_unlock(&md->mutex);
 252
 253         return count;
 254 }
 255
 256 static ssize_t w1_master_attribute_show_search(struct device *dev,
 257                                                struct device_attribute *attr,
 258                                                char *buf)
 259 {
 260         struct w1_master *md = dev_to_w1_master(dev);
 261         ssize_t count;
 262
 263         mutex_lock(&md->mutex);
 264         count = sprintf(buf, "%d\n", md->search_count);
 265         mutex_unlock(&md->mutex);
 266
 267         return count;
 268 }
 269
 270 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 271 {
 272         struct w1_master *md = dev_to_w1_master(dev);
 273         ssize_t count;
 274
 275         mutex_lock(&md->mutex);
 276         count = sprintf(buf, "0x%p\n", md->bus_master);
 277         mutex_unlock(&md->mutex);
 278         return count;
 279 }
 280
 281 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 282 {
 283         ssize_t count;
 284         count = sprintf(buf, "%d\n", w1_timeout);
 285         return count;
 286 }
 287
 288 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 289 {
 290         struct w1_master *md = dev_to_w1_master(dev);
 291         ssize_t count;
 292
 293         mutex_lock(&md->mutex);
 294         count = sprintf(buf, "%d\n", md->max_slave_count);
 295         mutex_unlock(&md->mutex);
 296         return count;
 297 }
 298
 299 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 300 {
 301         struct w1_master *md = dev_to_w1_master(dev);
 302         ssize_t count;
 303
 304         mutex_lock(&md->mutex);
 305         count = sprintf(buf, "%lu\n", md->attempts);
 306         mutex_unlock(&md->mutex);
 307         return count;
 308 }
 309
 310 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 311 {
 312         struct w1_master *md = dev_to_w1_master(dev);
 313         ssize_t count;
 314
 315         mutex_lock(&md->mutex);
 316         count = sprintf(buf, "%d\n", md->slave_count);
 317         mutex_unlock(&md->mutex);
 318         return count;
 319 }
 320
 321 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 322 {
 323         struct w1_master *md = dev_to_w1_master(dev);
 324         int c = PAGE_SIZE;
 325
 326         mutex_lock(&md->mutex);
 327
 328         if (md->slave_count == 0)
 329                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 330         else {
 331                 struct list_head *ent, *n;
 332                 struct w1_slave *sl;
 333
 334                 list_for_each_safe(ent, n, &md->slist) {
 335                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 336
 337                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 338                 }
 339         }
 340
 341         mutex_unlock(&md->mutex);
 342
 343         return PAGE_SIZE - c;
 344 }
 345
 346 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 347         struct device_attribute w1_master_attribute_##_name =   \
 348                 __ATTR(w1_master_##_name, _mode,                \
 349                        w1_master_attribute_show_##_name, NULL)
 350
 351 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 352         struct device_attribute w1_master_attribute_##_name =   \
 353                 __ATTR(w1_master_##_name, _mode,                \
 354                        w1_master_attribute_show_##_name,        \
 355                        w1_master_attribute_store_##_name)
 356
 357 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 358 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 359 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 360 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 361 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 362 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 363 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 364 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 365
 366 static struct attribute *w1_master_default_attrs[] = {
 367         &w1_master_attribute_name.attr,
 368         &w1_master_attribute_slaves.attr,
 369         &w1_master_attribute_slave_count.attr,
 370         &w1_master_attribute_max_slave_count.attr,
 371         &w1_master_attribute_attempts.attr,
 372         &w1_master_attribute_timeout.attr,
 373         &w1_master_attribute_pointer.attr,
 374         &w1_master_attribute_search.attr,
 375         NULL
 376 };
 377
 378 static struct attribute_group w1_master_defattr_group = {
 379         .attrs = w1_master_default_attrs,
 380 };
 381
 382 int w1_create_master_attributes(struct w1_master *master)
 383 {
 384         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 385 }
 386
 387 static void w1_destroy_master_attributes(struct w1_master *master)
 388 {
 389         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 390 }
 391
 392 #ifdef CONFIG_HOTPLUG
 393 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 394                         char *buffer, int buffer_size)
 395 {
 396         struct w1_master *md = NULL;
 397         struct w1_slave *sl = NULL;
 398         char *event_owner, *name;
 399         int err, cur_index=0, cur_len=0;
 400
 401         if (dev->driver == &w1_master_driver) {
 402                 md = container_of(dev, struct w1_master, dev);
 403                 event_owner = "master";
 404                 name = md->name;
 405         } else if (dev->driver == &w1_slave_driver) {
 406                 sl = container_of(dev, struct w1_slave, dev);
 407                 event_owner = "slave";
 408                 name = sl->name;
 409         } else {
 410                 dev_dbg(dev, "Unknown event.\n");
 411                 return -EINVAL;
 412         }
 413
 414         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 415                         event_owner, name, dev->bus_id);
 416
 417         if (dev->driver != &w1_slave_driver || !sl)
 418                 return 0;
 419
 420         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 421                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
 422         if (err)
 423                 return err;
 424
 425         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 426                         &cur_len, "W1_SLAVE_ID=%024LX",
 427                         (unsigned long long)sl->reg_num.id);
 428         if (err)
 429                 return err;
 430
 431         return 0;
 432 };
 433 #else
 434 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 435                         char *buffer, int buffer_size)
 436 {
 437         return 0;
 438 }
 439 #endif
 440
 441 static int __w1_attach_slave_device(struct w1_slave *sl)
 442 {
 443         int err;
 444
 445         sl->dev.parent = &sl->master->dev;
 446         sl->dev.driver = &w1_slave_driver;
 447         sl->dev.bus = &w1_bus_type;
 448         sl->dev.release = &w1_slave_release;
 449
 450         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 451                  "%02x-%012llx",
 452                  (unsigned int) sl->reg_num.family,
 453                  (unsigned long long) sl->reg_num.id);
 454         snprintf(&sl->name[0], sizeof(sl->name),
 455                  "%02x-%012llx",
 456                  (unsigned int) sl->reg_num.family,
 457                  (unsigned long long) sl->reg_num.id);
 458
 459         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 460                 &sl->dev.bus_id[0], sl);
 461
 462         err = device_register(&sl->dev);
 463         if (err < 0) {
 464                 dev_err(&sl->dev,
 465                         "Device registration [%s] failed. err=%d\n",
 466                         sl->dev.bus_id, err);
 467                 return err;
 468         }
 469
 470         /* Create "name" entry */
 471         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 472         if (err < 0) {
 473                 dev_err(&sl->dev,
 474                         "sysfs file creation for [%s] failed. err=%d\n",
 475                         sl->dev.bus_id, err);
 476                 goto out_unreg;
 477         }
 478
 479         /* Create "id" entry */
 480         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 481         if (err < 0) {
 482                 dev_err(&sl->dev,
 483                         "sysfs file creation for [%s] failed. err=%d\n",
 484                         sl->dev.bus_id, err);
 485                 goto out_rem1;
 486         }
 487
 488         /* if the family driver needs to initialize something... */
 489         if (sl->family->fops && sl->family->fops->add_slave &&
 490             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 491                 dev_err(&sl->dev,
 492                         "sysfs file creation for [%s] failed. err=%d\n",
 493                         sl->dev.bus_id, err);
 494                 goto out_rem2;
 495         }
 496
 497         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 498
 499         return 0;
 500
 501 out_rem2:
 502         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 503 out_rem1:
 504         device_remove_file(&sl->dev, &w1_slave_attr_name);
 505 out_unreg:
 506         device_unregister(&sl->dev);
 507         return err;
 508 }
 509
 510 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 511 {
 512         struct w1_slave *sl;
 513         struct w1_family *f;
 514         int err;
 515         struct w1_netlink_msg msg;
 516
 517         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 518         if (!sl) {
 519                 dev_err(&dev->dev,
 520                          "%s: failed to allocate new slave device.\n",
 521                          __func__);
 522                 return -ENOMEM;
 523         }
 524
 525         memset(sl, 0, sizeof(*sl));
 526
 527         sl->owner = THIS_MODULE;
 528         sl->master = dev;
 529         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 530
 531         memset(&msg, 0, sizeof(msg));
 532         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 533         atomic_set(&sl->refcnt, 0);
 534         init_completion(&sl->released);
 535
 536         spin_lock(&w1_flock);
 537         f = w1_family_registered(rn->family);
 538         if (!f) {
 539                 f= &w1_default_family;
 540                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 541                           rn->family, rn->family,
 542                           (unsigned long long)rn->id, rn->crc);
 543         }
 544         __w1_family_get(f);
 545         spin_unlock(&w1_flock);
 546
 547         sl->family = f;
 548
 549
 550         err = __w1_attach_slave_device(sl);
 551         if (err < 0) {
 552                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 553                          sl->name);
 554                 w1_family_put(sl->family);
 555                 kfree(sl);
 556                 return err;
 557         }
 558
 559         sl->ttl = dev->slave_ttl;
 560         dev->slave_count++;
 561
 562         memcpy(msg.id.id, rn, sizeof(msg.id));
 563         msg.type = W1_SLAVE_ADD;
 564         w1_netlink_send(dev, &msg);
 565
 566         return 0;
 567 }
 568
 569 static void w1_slave_detach(struct w1_slave *sl)
 570 {
 571         struct w1_netlink_msg msg;
 572
 573         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 574
 575         list_del(&sl->w1_slave_entry);
 576
 577         if (sl->family->fops && sl->family->fops->remove_slave)
 578                 sl->family->fops->remove_slave(sl);
 579
 580         memset(&msg, 0, sizeof(msg));
 581         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 582         msg.type = W1_SLAVE_REMOVE;
 583         w1_netlink_send(sl->master, &msg);
 584
 585         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 586         device_remove_file(&sl->dev, &w1_slave_attr_name);
 587         device_unregister(&sl->dev);
 588
 589         wait_for_completion(&sl->released);
 590         kfree(sl);
 591 }
 592
 593 static struct w1_master *w1_search_master(void *data)
 594 {
 595         struct w1_master *dev;
 596         int found = 0;
 597
 598         mutex_lock(&w1_mlock);
 599         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 600                 if (dev->bus_master->data == data) {
 601                         found = 1;
 602                         atomic_inc(&dev->refcnt);
 603                         break;
 604                 }
 605         }
 606         mutex_unlock(&w1_mlock);
 607
 608         return (found)?dev:NULL;
 609 }
 610
 611 struct w1_master *w1_search_master_id(u32 id)
 612 {
 613         struct w1_master *dev;
 614         int found = 0;
 615
 616         mutex_lock(&w1_mlock);
 617         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 618                 if (dev->id == id) {
 619                         found = 1;
 620                         atomic_inc(&dev->refcnt);
 621                         break;
 622                 }
 623         }
 624         mutex_unlock(&w1_mlock);
 625
 626         return (found)?dev:NULL;
 627 }
 628
 629 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 630 {
 631         struct w1_master *dev;
 632         struct w1_slave *sl = NULL;
 633         int found = 0;
 634
 635         mutex_lock(&w1_mlock);
 636         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 637                 mutex_lock(&dev->mutex);
 638                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 639                         if (sl->reg_num.family == id->family &&
 640                                         sl->reg_num.id == id->id &&
 641                                         sl->reg_num.crc == id->crc) {
 642                                 found = 1;
 643                                 atomic_inc(&dev->refcnt);
 644                                 atomic_inc(&sl->refcnt);
 645                                 break;
 646                         }
 647                 }
 648                 mutex_unlock(&dev->mutex);
 649
 650                 if (found)
 651                         break;
 652         }
 653         mutex_unlock(&w1_mlock);
 654
 655         return (found)?sl:NULL;
 656 }
 657
 658 void w1_reconnect_slaves(struct w1_family *f)
 659 {
 660         struct w1_master *dev;
 661
 662         mutex_lock(&w1_mlock);
 663         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 664                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 665                                 dev->name, f->fid);
 666                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 667         }
 668         mutex_unlock(&w1_mlock);
 669 }
 670
 671 static void w1_slave_found(void *data, u64 rn)
 672 {
 673         int slave_count;
 674         struct w1_slave *sl;
 675         struct list_head *ent;
 676         struct w1_reg_num *tmp;
 677         int family_found = 0;
 678         struct w1_master *dev;
 679         u64 rn_le = cpu_to_le64(rn);
 680
 681         dev = w1_search_master(data);
 682         if (!dev) {
 683                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 684                        "it is impossible.\n", data);
 685                 return;
 686         }
 687
 688         tmp = (struct w1_reg_num *) &rn;
 689
 690         slave_count = 0;
 691         list_for_each(ent, &dev->slist) {
 692
 693                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 694
 695                 if (sl->reg_num.family == tmp->family &&
 696                     sl->reg_num.id == tmp->id &&
 697                     sl->reg_num.crc == tmp->crc) {
 698                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 699                         break;
 700                 } else if (sl->reg_num.family == tmp->family) {
 701                         family_found = 1;
 702                         break;
 703                 }
 704
 705                 slave_count++;
 706         }
 707
 708         if (slave_count == dev->slave_count &&
 709                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 710                 w1_attach_slave_device(dev, tmp);
 711         }
 712
 713         atomic_dec(&dev->refcnt);
 714 }
 715
 716 /**
 717  * Performs a ROM Search & registers any devices found.
 718  * The 1-wire search is a simple binary tree search.
 719  * For each bit of the address, we read two bits and write one bit.
 720  * The bit written will put to sleep all devies that don't match that bit.
 721  * When the two reads differ, the direction choice is obvious.
 722  * When both bits are 0, we must choose a path to take.
 723  * When we can scan all 64 bits without having to choose a path, we are done.
 724  *
 725  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 726  *
 727  * @dev        The master device to search
 728  * @cb         Function to call when a device is found
 729  */
 730 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 731 {
 732         u64 last_rn, rn, tmp64;
 733         int i, slave_count = 0;
 734         int last_zero, last_device;
 735         int search_bit, desc_bit;
 736         u8  triplet_ret = 0;
 737
 738         search_bit = 0;
 739         rn = last_rn = 0;
 740         last_device = 0;
 741         last_zero = -1;
 742
 743         desc_bit = 64;
 744
 745         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 746                 last_rn = rn;
 747                 rn = 0;
 748
 749                 /*
 750                  * Reset bus and all 1-wire device state machines
 751                  * so they can respond to our requests.
 752                  *
 753                  * Return 0 - device(s) present, 1 - no devices present.
 754                  */
 755                 if (w1_reset_bus(dev)) {
 756                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 757                         break;
 758                 }
 759
 760                 /* Start the search */
 761                 w1_write_8(dev, search_type);
 762                 for (i = 0; i < 64; ++i) {
 763                         /* Determine the direction/search bit */
 764                         if (i == desc_bit)
 765                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 766                         else if (i > desc_bit)
 767                                 search_bit = 0;   /* take the 0 path on the next branch */
 768                         else
 769                                 search_bit = ((last_rn >> i) & 0x1);
 770
 771                         /** Read two bits and write one bit */
 772                         triplet_ret = w1_triplet(dev, search_bit);
 773
 774                         /* quit if no device responded */
 775                         if ( (triplet_ret & 0x03) == 0x03 )
 776                                 break;
 777
 778                         /* If both directions were valid, and we took the 0 path... */
 779                         if (triplet_ret == 0)
 780                                 last_zero = i;
 781
 782                         /* extract the direction taken & update the device number */
 783                         tmp64 = (triplet_ret >> 2);
 784                         rn |= (tmp64 << i);
 785                 }
 786
 787                 if ( (triplet_ret & 0x03) != 0x03 ) {
 788                         if ( (desc_bit == last_zero) || (last_zero < 0))
 789                                 last_device = 1;
 790                         desc_bit = last_zero;
 791                         cb(dev->bus_master->data, rn);
 792                 }
 793         }
 794 }
 795
 796 static int w1_control(void *data)
 797 {
 798         struct w1_slave *sl, *sln;
 799         struct w1_master *dev, *n;
 800         int have_to_wait = 0;
 801
 802         while (!kthread_should_stop() || have_to_wait) {
 803                 have_to_wait = 0;
 804
 805                 try_to_freeze();
 806                 msleep_interruptible(w1_control_timeout * 1000);
 807
 808                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 809                         if (!kthread_should_stop() && !dev->flags)
 810                                 continue;
 811                         /*
 812                          * Little race: we can create thread but not set the flag.
 813                          * Get a chance for external process to set flag up.
 814                          */
 815                         if (!dev->initialized) {
 816                                 have_to_wait = 1;
 817                                 continue;
 818                         }
 819
 820                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 821                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 822
 823                                 mutex_lock(&w1_mlock);
 824                                 list_del(&dev->w1_master_entry);
 825                                 mutex_unlock(&w1_mlock);
 826
 827                                 mutex_lock(&dev->mutex);
 828                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 829                                         w1_slave_detach(sl);
 830                                 }
 831                                 w1_destroy_master_attributes(dev);
 832                                 mutex_unlock(&dev->mutex);
 833                                 atomic_dec(&dev->refcnt);
 834                                 continue;
 835                         }
 836
 837                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 838                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 839                                 mutex_lock(&dev->mutex);
 840                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 841                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 842                                                 struct w1_reg_num rn;
 843
 844                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 845                                                 w1_slave_detach(sl);
 846
 847                                                 w1_attach_slave_device(dev, &rn);
 848                                         }
 849                                 }
 850                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 851                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 852                                 mutex_unlock(&dev->mutex);
 853                         }
 854                 }
 855         }
 856
 857         return 0;
 858 }
 859
 860 void w1_search_process(struct w1_master *dev, u8 search_type)
 861 {
 862         struct w1_slave *sl, *sln;
 863
 864         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 865                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 866
 867         w1_search_devices(dev, search_type, w1_slave_found);
 868
 869         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 870                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 871                         w1_slave_detach(sl);
 872
 873                         dev->slave_count--;
 874                 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 875                         sl->ttl = dev->slave_ttl;
 876         }
 877
 878         if (dev->search_count > 0)
 879                 dev->search_count--;
 880 }
 881
 882 int w1_process(void *data)
 883 {
 884         struct w1_master *dev = (struct w1_master *) data;
 885
 886         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 887                 try_to_freeze();
 888                 msleep_interruptible(w1_timeout * 1000);
 889
 890                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 891                         break;
 892
 893                 if (!dev->initialized)
 894                         continue;
 895
 896                 if (dev->search_count == 0)
 897                         continue;
 898
 899                 mutex_lock(&dev->mutex);
 900                 w1_search_process(dev, W1_SEARCH);
 901                 mutex_unlock(&dev->mutex);
 902         }
 903
 904         atomic_dec(&dev->refcnt);
 905
 906         return 0;
 907 }
 908
 909 static int w1_init(void)
 910 {
 911         int retval;
 912
 913         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 914
 915         w1_init_netlink();
 916
 917         retval = bus_register(&w1_bus_type);
 918         if (retval) {
 919                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 920                 goto err_out_exit_init;
 921         }
 922
 923         retval = driver_register(&w1_master_driver);
 924         if (retval) {
 925                 printk(KERN_ERR
 926                         "Failed to register master driver. err=%d.\n",
 927                         retval);
 928                 goto err_out_bus_unregister;
 929         }
 930
 931         retval = driver_register(&w1_slave_driver);
 932         if (retval) {
 933                 printk(KERN_ERR
 934                         "Failed to register master driver. err=%d.\n",
 935                         retval);
 936                 goto err_out_master_unregister;
 937         }
 938
 939         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 940         if (IS_ERR(w1_control_thread)) {
 941                 retval = PTR_ERR(w1_control_thread);
 942                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 943                         retval);
 944                 goto err_out_slave_unregister;
 945         }
 946
 947         return 0;
 948
 949 err_out_slave_unregister:
 950         driver_unregister(&w1_slave_driver);
 951
 952 err_out_master_unregister:
 953         driver_unregister(&w1_master_driver);
 954
 955 err_out_bus_unregister:
 956         bus_unregister(&w1_bus_type);
 957
 958 err_out_exit_init:
 959         return retval;
 960 }
 961
 962 static void w1_fini(void)
 963 {
 964         struct w1_master *dev;
 965
 966         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 967                 __w1_remove_master_device(dev);
 968
 969         w1_fini_netlink();
 970
 971         kthread_stop(w1_control_thread);
 972
 973         driver_unregister(&w1_slave_driver);
 974         driver_unregister(&w1_master_driver);
 975         bus_unregister(&w1_bus_type);
 976 }
 977
 978 module_init(w1_init);
 979 module_exit(w1_fini);