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   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33 #include <linux/kthread.h>
  34 #include <linux/freezer.h>
  35
  36 #include <asm/atomic.h>
  37
  38 #include "w1.h"
  39 #include "w1_log.h"
  40 #include "w1_int.h"
  41 #include "w1_family.h"
  42 #include "w1_netlink.h"
  43
  44 MODULE_LICENSE("GPL");
  45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  47
  48 static int w1_timeout = 10;
  49 static int w1_control_timeout = 1;
  50 int w1_max_slave_count = 10;
  51 int w1_max_slave_ttl = 10;
  52
  53 module_param_named(timeout, w1_timeout, int, 0);
  54 module_param_named(control_timeout, w1_control_timeout, int, 0);
  55 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  56 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  57
  58 DEFINE_MUTEX(w1_mlock);
  59 LIST_HEAD(w1_masters);
  60
  61 static struct task_struct *w1_control_thread;
  62
  63 static int w1_master_match(struct device *dev, struct device_driver *drv)
  64 {
  65         return 1;
  66 }
  67
  68 static int w1_master_probe(struct device *dev)
  69 {
  70         return -ENODEV;
  71 }
  72
  73 static void w1_master_release(struct device *dev)
  74 {
  75         struct w1_master *md = dev_to_w1_master(dev);
  76
  77         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  78         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  79         kfree(md);
  80 }
  81
  82 static void w1_slave_release(struct device *dev)
  83 {
  84         struct w1_slave *sl = dev_to_w1_slave(dev);
  85
  86         printk("%s: Releasing %s.\n", __func__, sl->name);
  87
  88         while (atomic_read(&sl->refcnt)) {
  89                 printk("Waiting for %s to become free: refcnt=%d.\n",
  90                                 sl->name, atomic_read(&sl->refcnt));
  91                 if (msleep_interruptible(1000))
  92                         flush_signals(current);
  93         }
  94
  95         w1_family_put(sl->family);
  96         sl->master->slave_count--;
  97
  98         complete(&sl->released);
  99 }
 100
 101 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 102 {
 103         struct w1_slave *sl = dev_to_w1_slave(dev);
 104
 105         return sprintf(buf, "%s\n", sl->name);
 106 }
 107
 108 static ssize_t w1_slave_read_id(struct kobject *kobj,
 109                                 struct bin_attribute *bin_attr,
 110                                 char *buf, loff_t off, size_t count)
 111 {
 112         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 113
 114         if (off > 8) {
 115                 count = 0;
 116         } else {
 117                 if (off + count > 8)
 118                         count = 8 - off;
 119
 120                 memcpy(buf, (u8 *)&sl->reg_num, count);
 121         }
 122
 123         return count;
 124 }
 125
 126 static struct device_attribute w1_slave_attr_name =
 127         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 128
 129 static struct bin_attribute w1_slave_attr_bin_id = {
 130       .attr = {
 131               .name = "id",
 132               .mode = S_IRUGO,
 133       },
 134       .size = 8,
 135       .read = w1_slave_read_id,
 136 };
 137
 138 /* Default family */
 139
 140 static ssize_t w1_default_write(struct kobject *kobj,
 141                                 struct bin_attribute *bin_attr,
 142                                 char *buf, loff_t off, size_t count)
 143 {
 144         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 145
 146         mutex_lock(&sl->master->mutex);
 147         if (w1_reset_select_slave(sl)) {
 148                 count = 0;
 149                 goto out_up;
 150         }
 151
 152         w1_write_block(sl->master, buf, count);
 153
 154 out_up:
 155         mutex_unlock(&sl->master->mutex);
 156         return count;
 157 }
 158
 159 static ssize_t w1_default_read(struct kobject *kobj,
 160                                struct bin_attribute *bin_attr,
 161                                char *buf, loff_t off, size_t count)
 162 {
 163         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 164
 165         mutex_lock(&sl->master->mutex);
 166         w1_read_block(sl->master, buf, count);
 167         mutex_unlock(&sl->master->mutex);
 168         return count;
 169 }
 170
 171 static struct bin_attribute w1_default_attr = {
 172       .attr = {
 173               .name = "rw",
 174               .mode = S_IRUGO | S_IWUSR,
 175       },
 176       .size = PAGE_SIZE,
 177       .read = w1_default_read,
 178       .write = w1_default_write,
 179 };
 180
 181 static int w1_default_add_slave(struct w1_slave *sl)
 182 {
 183         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 184 }
 185
 186 static void w1_default_remove_slave(struct w1_slave *sl)
 187 {
 188         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 189 }
 190
 191 static struct w1_family_ops w1_default_fops = {
 192         .add_slave      = w1_default_add_slave,
 193         .remove_slave   = w1_default_remove_slave,
 194 };
 195
 196 static struct w1_family w1_default_family = {
 197         .fops = &w1_default_fops,
 198 };
 199
 200 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 201
 202 static struct bus_type w1_bus_type = {
 203         .name = "w1",
 204         .match = w1_master_match,
 205         .uevent = w1_uevent,
 206 };
 207
 208 struct device_driver w1_master_driver = {
 209         .name = "w1_master_driver",
 210         .bus = &w1_bus_type,
 211         .probe = w1_master_probe,
 212 };
 213
 214 struct device w1_master_device = {
 215         .parent = NULL,
 216         .bus = &w1_bus_type,
 217         .bus_id = "w1 bus master",
 218         .driver = &w1_master_driver,
 219         .release = &w1_master_release
 220 };
 221
 222 static struct device_driver w1_slave_driver = {
 223         .name = "w1_slave_driver",
 224         .bus = &w1_bus_type,
 225 };
 226
 227 #if 0
 228 struct device w1_slave_device = {
 229         .parent = NULL,
 230         .bus = &w1_bus_type,
 231         .bus_id = "w1 bus slave",
 232         .driver = &w1_slave_driver,
 233         .release = &w1_slave_release
 234 };
 235 #endif  /*  0  */
 236
 237 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 238 {
 239         struct w1_master *md = dev_to_w1_master(dev);
 240         ssize_t count;
 241
 242         mutex_lock(&md->mutex);
 243         count = sprintf(buf, "%s\n", md->name);
 244         mutex_unlock(&md->mutex);
 245
 246         return count;
 247 }
 248
 249 static ssize_t w1_master_attribute_store_search(struct device * dev,
 250                                                 struct device_attribute *attr,
 251                                                 const char * buf, size_t count)
 252 {
 253         struct w1_master *md = dev_to_w1_master(dev);
 254
 255         mutex_lock(&md->mutex);
 256         md->search_count = simple_strtol(buf, NULL, 0);
 257         mutex_unlock(&md->mutex);
 258
 259         return count;
 260 }
 261
 262 static ssize_t w1_master_attribute_show_search(struct device *dev,
 263                                                struct device_attribute *attr,
 264                                                char *buf)
 265 {
 266         struct w1_master *md = dev_to_w1_master(dev);
 267         ssize_t count;
 268
 269         mutex_lock(&md->mutex);
 270         count = sprintf(buf, "%d\n", md->search_count);
 271         mutex_unlock(&md->mutex);
 272
 273         return count;
 274 }
 275
 276 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 277 {
 278         struct w1_master *md = dev_to_w1_master(dev);
 279         ssize_t count;
 280
 281         mutex_lock(&md->mutex);
 282         count = sprintf(buf, "0x%p\n", md->bus_master);
 283         mutex_unlock(&md->mutex);
 284         return count;
 285 }
 286
 287 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 288 {
 289         ssize_t count;
 290         count = sprintf(buf, "%d\n", w1_timeout);
 291         return count;
 292 }
 293
 294 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 295 {
 296         struct w1_master *md = dev_to_w1_master(dev);
 297         ssize_t count;
 298
 299         mutex_lock(&md->mutex);
 300         count = sprintf(buf, "%d\n", md->max_slave_count);
 301         mutex_unlock(&md->mutex);
 302         return count;
 303 }
 304
 305 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 306 {
 307         struct w1_master *md = dev_to_w1_master(dev);
 308         ssize_t count;
 309
 310         mutex_lock(&md->mutex);
 311         count = sprintf(buf, "%lu\n", md->attempts);
 312         mutex_unlock(&md->mutex);
 313         return count;
 314 }
 315
 316 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 317 {
 318         struct w1_master *md = dev_to_w1_master(dev);
 319         ssize_t count;
 320
 321         mutex_lock(&md->mutex);
 322         count = sprintf(buf, "%d\n", md->slave_count);
 323         mutex_unlock(&md->mutex);
 324         return count;
 325 }
 326
 327 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 328 {
 329         struct w1_master *md = dev_to_w1_master(dev);
 330         int c = PAGE_SIZE;
 331
 332         mutex_lock(&md->mutex);
 333
 334         if (md->slave_count == 0)
 335                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 336         else {
 337                 struct list_head *ent, *n;
 338                 struct w1_slave *sl;
 339
 340                 list_for_each_safe(ent, n, &md->slist) {
 341                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 342
 343                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 344                 }
 345         }
 346
 347         mutex_unlock(&md->mutex);
 348
 349         return PAGE_SIZE - c;
 350 }
 351
 352 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 353         struct device_attribute w1_master_attribute_##_name =   \
 354                 __ATTR(w1_master_##_name, _mode,                \
 355                        w1_master_attribute_show_##_name, NULL)
 356
 357 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 358         struct device_attribute w1_master_attribute_##_name =   \
 359                 __ATTR(w1_master_##_name, _mode,                \
 360                        w1_master_attribute_show_##_name,        \
 361                        w1_master_attribute_store_##_name)
 362
 363 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 364 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 365 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 366 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 367 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 368 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 369 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 370 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 371
 372 static struct attribute *w1_master_default_attrs[] = {
 373         &w1_master_attribute_name.attr,
 374         &w1_master_attribute_slaves.attr,
 375         &w1_master_attribute_slave_count.attr,
 376         &w1_master_attribute_max_slave_count.attr,
 377         &w1_master_attribute_attempts.attr,
 378         &w1_master_attribute_timeout.attr,
 379         &w1_master_attribute_pointer.attr,
 380         &w1_master_attribute_search.attr,
 381         NULL
 382 };
 383
 384 static struct attribute_group w1_master_defattr_group = {
 385         .attrs = w1_master_default_attrs,
 386 };
 387
 388 int w1_create_master_attributes(struct w1_master *master)
 389 {
 390         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 391 }
 392
 393 static void w1_destroy_master_attributes(struct w1_master *master)
 394 {
 395         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 396 }
 397
 398 #ifdef CONFIG_HOTPLUG
 399 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 400                         char *buffer, int buffer_size)
 401 {
 402         struct w1_master *md = NULL;
 403         struct w1_slave *sl = NULL;
 404         char *event_owner, *name;
 405         int err, cur_index=0, cur_len=0;
 406
 407         if (dev->driver == &w1_master_driver) {
 408                 md = container_of(dev, struct w1_master, dev);
 409                 event_owner = "master";
 410                 name = md->name;
 411         } else if (dev->driver == &w1_slave_driver) {
 412                 sl = container_of(dev, struct w1_slave, dev);
 413                 event_owner = "slave";
 414                 name = sl->name;
 415         } else {
 416                 dev_dbg(dev, "Unknown event.\n");
 417                 return -EINVAL;
 418         }
 419
 420         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 421                         event_owner, name, dev->bus_id);
 422
 423         if (dev->driver != &w1_slave_driver || !sl)
 424                 return 0;
 425
 426         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 427                         &cur_len, "W1_FID=%02X", sl->reg_num.family);
 428         if (err)
 429                 return err;
 430
 431         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
 432                         &cur_len, "W1_SLAVE_ID=%024LX",
 433                         (unsigned long long)sl->reg_num.id);
 434         if (err)
 435                 return err;
 436
 437         return 0;
 438 };
 439 #else
 440 static int w1_uevent(struct device *dev, char **envp, int num_envp,
 441                         char *buffer, int buffer_size)
 442 {
 443         return 0;
 444 }
 445 #endif
 446
 447 static int __w1_attach_slave_device(struct w1_slave *sl)
 448 {
 449         int err;
 450
 451         sl->dev.parent = &sl->master->dev;
 452         sl->dev.driver = &w1_slave_driver;
 453         sl->dev.bus = &w1_bus_type;
 454         sl->dev.release = &w1_slave_release;
 455
 456         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 457                  "%02x-%012llx",
 458                  (unsigned int) sl->reg_num.family,
 459                  (unsigned long long) sl->reg_num.id);
 460         snprintf(&sl->name[0], sizeof(sl->name),
 461                  "%02x-%012llx",
 462                  (unsigned int) sl->reg_num.family,
 463                  (unsigned long long) sl->reg_num.id);
 464
 465         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 466                 &sl->dev.bus_id[0], sl);
 467
 468         err = device_register(&sl->dev);
 469         if (err < 0) {
 470                 dev_err(&sl->dev,
 471                         "Device registration [%s] failed. err=%d\n",
 472                         sl->dev.bus_id, err);
 473                 return err;
 474         }
 475
 476         /* Create "name" entry */
 477         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 478         if (err < 0) {
 479                 dev_err(&sl->dev,
 480                         "sysfs file creation for [%s] failed. err=%d\n",
 481                         sl->dev.bus_id, err);
 482                 goto out_unreg;
 483         }
 484
 485         /* Create "id" entry */
 486         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 487         if (err < 0) {
 488                 dev_err(&sl->dev,
 489                         "sysfs file creation for [%s] failed. err=%d\n",
 490                         sl->dev.bus_id, err);
 491                 goto out_rem1;
 492         }
 493
 494         /* if the family driver needs to initialize something... */
 495         if (sl->family->fops && sl->family->fops->add_slave &&
 496             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 497                 dev_err(&sl->dev,
 498                         "sysfs file creation for [%s] failed. err=%d\n",
 499                         sl->dev.bus_id, err);
 500                 goto out_rem2;
 501         }
 502
 503         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 504
 505         return 0;
 506
 507 out_rem2:
 508         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 509 out_rem1:
 510         device_remove_file(&sl->dev, &w1_slave_attr_name);
 511 out_unreg:
 512         device_unregister(&sl->dev);
 513         return err;
 514 }
 515
 516 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 517 {
 518         struct w1_slave *sl;
 519         struct w1_family *f;
 520         int err;
 521         struct w1_netlink_msg msg;
 522
 523         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 524         if (!sl) {
 525                 dev_err(&dev->dev,
 526                          "%s: failed to allocate new slave device.\n",
 527                          __func__);
 528                 return -ENOMEM;
 529         }
 530
 531         memset(sl, 0, sizeof(*sl));
 532
 533         sl->owner = THIS_MODULE;
 534         sl->master = dev;
 535         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 536
 537         memset(&msg, 0, sizeof(msg));
 538         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 539         atomic_set(&sl->refcnt, 0);
 540         init_completion(&sl->released);
 541
 542         spin_lock(&w1_flock);
 543         f = w1_family_registered(rn->family);
 544         if (!f) {
 545                 f= &w1_default_family;
 546                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 547                           rn->family, rn->family,
 548                           (unsigned long long)rn->id, rn->crc);
 549         }
 550         __w1_family_get(f);
 551         spin_unlock(&w1_flock);
 552
 553         sl->family = f;
 554
 555
 556         err = __w1_attach_slave_device(sl);
 557         if (err < 0) {
 558                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 559                          sl->name);
 560                 w1_family_put(sl->family);
 561                 kfree(sl);
 562                 return err;
 563         }
 564
 565         sl->ttl = dev->slave_ttl;
 566         dev->slave_count++;
 567
 568         memcpy(msg.id.id, rn, sizeof(msg.id));
 569         msg.type = W1_SLAVE_ADD;
 570         w1_netlink_send(dev, &msg);
 571
 572         return 0;
 573 }
 574
 575 static void w1_slave_detach(struct w1_slave *sl)
 576 {
 577         struct w1_netlink_msg msg;
 578
 579         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 580
 581         list_del(&sl->w1_slave_entry);
 582
 583         if (sl->family->fops && sl->family->fops->remove_slave)
 584                 sl->family->fops->remove_slave(sl);
 585
 586         memset(&msg, 0, sizeof(msg));
 587         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 588         msg.type = W1_SLAVE_REMOVE;
 589         w1_netlink_send(sl->master, &msg);
 590
 591         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 592         device_remove_file(&sl->dev, &w1_slave_attr_name);
 593         device_unregister(&sl->dev);
 594
 595         wait_for_completion(&sl->released);
 596         kfree(sl);
 597 }
 598
 599 static struct w1_master *w1_search_master(void *data)
 600 {
 601         struct w1_master *dev;
 602         int found = 0;
 603
 604         mutex_lock(&w1_mlock);
 605         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 606                 if (dev->bus_master->data == data) {
 607                         found = 1;
 608                         atomic_inc(&dev->refcnt);
 609                         break;
 610                 }
 611         }
 612         mutex_unlock(&w1_mlock);
 613
 614         return (found)?dev:NULL;
 615 }
 616
 617 struct w1_master *w1_search_master_id(u32 id)
 618 {
 619         struct w1_master *dev;
 620         int found = 0;
 621
 622         mutex_lock(&w1_mlock);
 623         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 624                 if (dev->id == id) {
 625                         found = 1;
 626                         atomic_inc(&dev->refcnt);
 627                         break;
 628                 }
 629         }
 630         mutex_unlock(&w1_mlock);
 631
 632         return (found)?dev:NULL;
 633 }
 634
 635 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 636 {
 637         struct w1_master *dev;
 638         struct w1_slave *sl = NULL;
 639         int found = 0;
 640
 641         mutex_lock(&w1_mlock);
 642         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 643                 mutex_lock(&dev->mutex);
 644                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 645                         if (sl->reg_num.family == id->family &&
 646                                         sl->reg_num.id == id->id &&
 647                                         sl->reg_num.crc == id->crc) {
 648                                 found = 1;
 649                                 atomic_inc(&dev->refcnt);
 650                                 atomic_inc(&sl->refcnt);
 651                                 break;
 652                         }
 653                 }
 654                 mutex_unlock(&dev->mutex);
 655
 656                 if (found)
 657                         break;
 658         }
 659         mutex_unlock(&w1_mlock);
 660
 661         return (found)?sl:NULL;
 662 }
 663
 664 void w1_reconnect_slaves(struct w1_family *f)
 665 {
 666         struct w1_master *dev;
 667
 668         mutex_lock(&w1_mlock);
 669         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 670                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 671                                 dev->name, f->fid);
 672                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 673         }
 674         mutex_unlock(&w1_mlock);
 675 }
 676
 677 static void w1_slave_found(void *data, u64 rn)
 678 {
 679         int slave_count;
 680         struct w1_slave *sl;
 681         struct list_head *ent;
 682         struct w1_reg_num *tmp;
 683         int family_found = 0;
 684         struct w1_master *dev;
 685         u64 rn_le = cpu_to_le64(rn);
 686
 687         dev = w1_search_master(data);
 688         if (!dev) {
 689                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 690                        "it is impossible.\n", data);
 691                 return;
 692         }
 693
 694         tmp = (struct w1_reg_num *) &rn;
 695
 696         slave_count = 0;
 697         list_for_each(ent, &dev->slist) {
 698
 699                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 700
 701                 if (sl->reg_num.family == tmp->family &&
 702                     sl->reg_num.id == tmp->id &&
 703                     sl->reg_num.crc == tmp->crc) {
 704                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 705                         break;
 706                 } else if (sl->reg_num.family == tmp->family) {
 707                         family_found = 1;
 708                         break;
 709                 }
 710
 711                 slave_count++;
 712         }
 713
 714         if (slave_count == dev->slave_count &&
 715                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 716                 w1_attach_slave_device(dev, tmp);
 717         }
 718
 719         atomic_dec(&dev->refcnt);
 720 }
 721
 722 /**
 723  * Performs a ROM Search & registers any devices found.
 724  * The 1-wire search is a simple binary tree search.
 725  * For each bit of the address, we read two bits and write one bit.
 726  * The bit written will put to sleep all devies that don't match that bit.
 727  * When the two reads differ, the direction choice is obvious.
 728  * When both bits are 0, we must choose a path to take.
 729  * When we can scan all 64 bits without having to choose a path, we are done.
 730  *
 731  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 732  *
 733  * @dev        The master device to search
 734  * @cb         Function to call when a device is found
 735  */
 736 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 737 {
 738         u64 last_rn, rn, tmp64;
 739         int i, slave_count = 0;
 740         int last_zero, last_device;
 741         int search_bit, desc_bit;
 742         u8  triplet_ret = 0;
 743
 744         search_bit = 0;
 745         rn = last_rn = 0;
 746         last_device = 0;
 747         last_zero = -1;
 748
 749         desc_bit = 64;
 750
 751         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 752                 last_rn = rn;
 753                 rn = 0;
 754
 755                 /*
 756                  * Reset bus and all 1-wire device state machines
 757                  * so they can respond to our requests.
 758                  *
 759                  * Return 0 - device(s) present, 1 - no devices present.
 760                  */
 761                 if (w1_reset_bus(dev)) {
 762                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 763                         break;
 764                 }
 765
 766                 /* Start the search */
 767                 w1_write_8(dev, search_type);
 768                 for (i = 0; i < 64; ++i) {
 769                         /* Determine the direction/search bit */
 770                         if (i == desc_bit)
 771                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 772                         else if (i > desc_bit)
 773                                 search_bit = 0;   /* take the 0 path on the next branch */
 774                         else
 775                                 search_bit = ((last_rn >> i) & 0x1);
 776
 777                         /** Read two bits and write one bit */
 778                         triplet_ret = w1_triplet(dev, search_bit);
 779
 780                         /* quit if no device responded */
 781                         if ( (triplet_ret & 0x03) == 0x03 )
 782                                 break;
 783
 784                         /* If both directions were valid, and we took the 0 path... */
 785                         if (triplet_ret == 0)
 786                                 last_zero = i;
 787
 788                         /* extract the direction taken & update the device number */
 789                         tmp64 = (triplet_ret >> 2);
 790                         rn |= (tmp64 << i);
 791                 }
 792
 793                 if ( (triplet_ret & 0x03) != 0x03 ) {
 794                         if ( (desc_bit == last_zero) || (last_zero < 0))
 795                                 last_device = 1;
 796                         desc_bit = last_zero;
 797                         cb(dev->bus_master->data, rn);
 798                 }
 799         }
 800 }
 801
 802 static int w1_control(void *data)
 803 {
 804         struct w1_slave *sl, *sln;
 805         struct w1_master *dev, *n;
 806         int have_to_wait = 0;
 807
 808         set_freezable();
 809         while (!kthread_should_stop() || have_to_wait) {
 810                 have_to_wait = 0;
 811
 812                 try_to_freeze();
 813                 msleep_interruptible(w1_control_timeout * 1000);
 814
 815                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 816                         if (!kthread_should_stop() && !dev->flags)
 817                                 continue;
 818                         /*
 819                          * Little race: we can create thread but not set the flag.
 820                          * Get a chance for external process to set flag up.
 821                          */
 822                         if (!dev->initialized) {
 823                                 have_to_wait = 1;
 824                                 continue;
 825                         }
 826
 827                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 828                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 829
 830                                 mutex_lock(&w1_mlock);
 831                                 list_del(&dev->w1_master_entry);
 832                                 mutex_unlock(&w1_mlock);
 833
 834                                 mutex_lock(&dev->mutex);
 835                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 836                                         w1_slave_detach(sl);
 837                                 }
 838                                 w1_destroy_master_attributes(dev);
 839                                 mutex_unlock(&dev->mutex);
 840                                 atomic_dec(&dev->refcnt);
 841                                 continue;
 842                         }
 843
 844                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 845                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 846                                 mutex_lock(&dev->mutex);
 847                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 848                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 849                                                 struct w1_reg_num rn;
 850
 851                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 852                                                 w1_slave_detach(sl);
 853
 854                                                 w1_attach_slave_device(dev, &rn);
 855                                         }
 856                                 }
 857                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 858                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 859                                 mutex_unlock(&dev->mutex);
 860                         }
 861                 }
 862         }
 863
 864         return 0;
 865 }
 866
 867 void w1_search_process(struct w1_master *dev, u8 search_type)
 868 {
 869         struct w1_slave *sl, *sln;
 870
 871         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 872                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 873
 874         w1_search_devices(dev, search_type, w1_slave_found);
 875
 876         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 877                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 878                         w1_slave_detach(sl);
 879
 880                         dev->slave_count--;
 881                 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 882                         sl->ttl = dev->slave_ttl;
 883         }
 884
 885         if (dev->search_count > 0)
 886                 dev->search_count--;
 887 }
 888
 889 int w1_process(void *data)
 890 {
 891         struct w1_master *dev = (struct w1_master *) data;
 892
 893         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 894                 try_to_freeze();
 895                 msleep_interruptible(w1_timeout * 1000);
 896
 897                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 898                         break;
 899
 900                 if (!dev->initialized)
 901                         continue;
 902
 903                 if (dev->search_count == 0)
 904                         continue;
 905
 906                 mutex_lock(&dev->mutex);
 907                 w1_search_process(dev, W1_SEARCH);
 908                 mutex_unlock(&dev->mutex);
 909         }
 910
 911         atomic_dec(&dev->refcnt);
 912
 913         return 0;
 914 }
 915
 916 static int w1_init(void)
 917 {
 918         int retval;
 919
 920         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 921
 922         w1_init_netlink();
 923
 924         retval = bus_register(&w1_bus_type);
 925         if (retval) {
 926                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 927                 goto err_out_exit_init;
 928         }
 929
 930         retval = driver_register(&w1_master_driver);
 931         if (retval) {
 932                 printk(KERN_ERR
 933                         "Failed to register master driver. err=%d.\n",
 934                         retval);
 935                 goto err_out_bus_unregister;
 936         }
 937
 938         retval = driver_register(&w1_slave_driver);
 939         if (retval) {
 940                 printk(KERN_ERR
 941                         "Failed to register master driver. err=%d.\n",
 942                         retval);
 943                 goto err_out_master_unregister;
 944         }
 945
 946         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 947         if (IS_ERR(w1_control_thread)) {
 948                 retval = PTR_ERR(w1_control_thread);
 949                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 950                         retval);
 951                 goto err_out_slave_unregister;
 952         }
 953
 954         return 0;
 955
 956 err_out_slave_unregister:
 957         driver_unregister(&w1_slave_driver);
 958
 959 err_out_master_unregister:
 960         driver_unregister(&w1_master_driver);
 961
 962 err_out_bus_unregister:
 963         bus_unregister(&w1_bus_type);
 964
 965 err_out_exit_init:
 966         return retval;
 967 }
 968
 969 static void w1_fini(void)
 970 {
 971         struct w1_master *dev;
 972
 973         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 974                 __w1_remove_master_device(dev);
 975
 976         w1_fini_netlink();
 977
 978         kthread_stop(w1_control_thread);
 979
 980         driver_unregister(&w1_slave_driver);
 981         driver_unregister(&w1_master_driver);
 982         bus_unregister(&w1_bus_type);
 983 }
 984
 985 module_init(w1_init);
 986 module_exit(w1_fini);