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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
  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 DECLARE_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         if (down_interruptible(&sl->master->mutex)) {
 143                 count = 0;
 144                 goto out;
 145         }
 146
 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         up(&sl->master->mutex);
 156 out:
 157         return count;
 158 }
 159
 160 static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
 161 {
 162         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 163
 164         if (down_interruptible(&sl->master->mutex)) {
 165                 count = 0;
 166                 goto out;
 167         }
 168
 169         w1_read_block(sl->master, buf, count);
 170
 171         up(&sl->master->mutex);
 172 out:
 173         return count;
 174 }
 175
 176 static struct bin_attribute w1_default_attr = {
 177       .attr = {
 178               .name = "rw",
 179               .mode = S_IRUGO | S_IWUSR,
 180               .owner = THIS_MODULE,
 181       },
 182       .size = PAGE_SIZE,
 183       .read = w1_default_read,
 184       .write = w1_default_write,
 185 };
 186
 187 static int w1_default_add_slave(struct w1_slave *sl)
 188 {
 189         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 190 }
 191
 192 static void w1_default_remove_slave(struct w1_slave *sl)
 193 {
 194         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 195 }
 196
 197 static struct w1_family_ops w1_default_fops = {
 198         .add_slave      = w1_default_add_slave,
 199         .remove_slave   = w1_default_remove_slave,
 200 };
 201
 202 static struct w1_family w1_default_family = {
 203         .fops = &w1_default_fops,
 204 };
 205
 206 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 207
 208 static struct bus_type w1_bus_type = {
 209         .name = "w1",
 210         .match = w1_master_match,
 211         .uevent = w1_uevent,
 212 };
 213
 214 struct device_driver w1_master_driver = {
 215         .name = "w1_master_driver",
 216         .bus = &w1_bus_type,
 217         .probe = w1_master_probe,
 218 };
 219
 220 struct device w1_master_device = {
 221         .parent = NULL,
 222         .bus = &w1_bus_type,
 223         .bus_id = "w1 bus master",
 224         .driver = &w1_master_driver,
 225         .release = &w1_master_release
 226 };
 227
 228 struct device_driver w1_slave_driver = {
 229         .name = "w1_slave_driver",
 230         .bus = &w1_bus_type,
 231 };
 232
 233 struct device w1_slave_device = {
 234         .parent = NULL,
 235         .bus = &w1_bus_type,
 236         .bus_id = "w1 bus slave",
 237         .driver = &w1_slave_driver,
 238         .release = &w1_slave_release
 239 };
 240
 241 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 242 {
 243         struct w1_master *md = dev_to_w1_master(dev);
 244         ssize_t count;
 245
 246         if (down_interruptible (&md->mutex))
 247                 return -EBUSY;
 248
 249         count = sprintf(buf, "%s\n", md->name);
 250
 251         up(&md->mutex);
 252
 253         return count;
 254 }
 255
 256 static ssize_t w1_master_attribute_store_search(struct device * dev,
 257                                                 struct device_attribute *attr,
 258                                                 const char * buf, size_t count)
 259 {
 260         struct w1_master *md = dev_to_w1_master(dev);
 261
 262         if (down_interruptible (&md->mutex))
 263                 return -EBUSY;
 264
 265         md->search_count = simple_strtol(buf, NULL, 0);
 266
 267         up(&md->mutex);
 268
 269         return count;
 270 }
 271
 272 static ssize_t w1_master_attribute_show_search(struct device *dev,
 273                                                struct device_attribute *attr,
 274                                                char *buf)
 275 {
 276         struct w1_master *md = dev_to_w1_master(dev);
 277         ssize_t count;
 278
 279         if (down_interruptible (&md->mutex))
 280                 return -EBUSY;
 281
 282         count = sprintf(buf, "%d\n", md->search_count);
 283
 284         up(&md->mutex);
 285
 286         return count;
 287 }
 288
 289 static ssize_t w1_master_attribute_show_pointer(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         if (down_interruptible(&md->mutex))
 295                 return -EBUSY;
 296
 297         count = sprintf(buf, "0x%p\n", md->bus_master);
 298
 299         up(&md->mutex);
 300         return count;
 301 }
 302
 303 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 304 {
 305         ssize_t count;
 306         count = sprintf(buf, "%d\n", w1_timeout);
 307         return count;
 308 }
 309
 310 static ssize_t w1_master_attribute_show_max_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         if (down_interruptible(&md->mutex))
 316                 return -EBUSY;
 317
 318         count = sprintf(buf, "%d\n", md->max_slave_count);
 319
 320         up(&md->mutex);
 321         return count;
 322 }
 323
 324 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 325 {
 326         struct w1_master *md = dev_to_w1_master(dev);
 327         ssize_t count;
 328
 329         if (down_interruptible(&md->mutex))
 330                 return -EBUSY;
 331
 332         count = sprintf(buf, "%lu\n", md->attempts);
 333
 334         up(&md->mutex);
 335         return count;
 336 }
 337
 338 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 339 {
 340         struct w1_master *md = dev_to_w1_master(dev);
 341         ssize_t count;
 342
 343         if (down_interruptible(&md->mutex))
 344                 return -EBUSY;
 345
 346         count = sprintf(buf, "%d\n", md->slave_count);
 347
 348         up(&md->mutex);
 349         return count;
 350 }
 351
 352 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 353 {
 354         struct w1_master *md = dev_to_w1_master(dev);
 355         int c = PAGE_SIZE;
 356
 357         if (down_interruptible(&md->mutex))
 358                 return -EBUSY;
 359
 360         if (md->slave_count == 0)
 361                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 362         else {
 363                 struct list_head *ent, *n;
 364                 struct w1_slave *sl;
 365
 366                 list_for_each_safe(ent, n, &md->slist) {
 367                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 368
 369                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 370                 }
 371         }
 372
 373         up(&md->mutex);
 374
 375         return PAGE_SIZE - c;
 376 }
 377
 378 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 379         struct device_attribute w1_master_attribute_##_name =   \
 380                 __ATTR(w1_master_##_name, _mode,                \
 381                        w1_master_attribute_show_##_name, NULL)
 382
 383 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 384         struct device_attribute w1_master_attribute_##_name =   \
 385                 __ATTR(w1_master_##_name, _mode,                \
 386                        w1_master_attribute_show_##_name,        \
 387                        w1_master_attribute_store_##_name)
 388
 389 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 390 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 391 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 392 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 393 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 394 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 395 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 396 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 397
 398 static struct attribute *w1_master_default_attrs[] = {
 399         &w1_master_attribute_name.attr,
 400         &w1_master_attribute_slaves.attr,
 401         &w1_master_attribute_slave_count.attr,
 402         &w1_master_attribute_max_slave_count.attr,
 403         &w1_master_attribute_attempts.attr,
 404         &w1_master_attribute_timeout.attr,
 405         &w1_master_attribute_pointer.attr,
 406         &w1_master_attribute_search.attr,
 407         NULL
 408 };
 409
 410 static struct attribute_group w1_master_defattr_group = {
 411         .attrs = w1_master_default_attrs,
 412 };
 413
 414 int w1_create_master_attributes(struct w1_master *master)
 415 {
 416         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 417 }
 418
 419 void w1_destroy_master_attributes(struct w1_master *master)
 420 {
 421         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 422 }
 423
 424 #ifdef CONFIG_HOTPLUG
 425 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 426 {
 427         struct w1_master *md = NULL;
 428         struct w1_slave *sl = NULL;
 429         char *event_owner, *name;
 430         int err, cur_index=0, cur_len=0;
 431
 432         if (dev->driver == &w1_master_driver) {
 433                 md = container_of(dev, struct w1_master, dev);
 434                 event_owner = "master";
 435                 name = md->name;
 436         } else if (dev->driver == &w1_slave_driver) {
 437                 sl = container_of(dev, struct w1_slave, dev);
 438                 event_owner = "slave";
 439                 name = sl->name;
 440         } else {
 441                 dev_dbg(dev, "Unknown event.\n");
 442                 return -EINVAL;
 443         }
 444
 445         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
 446
 447         if (dev->driver != &w1_slave_driver || !sl)
 448                 return 0;
 449
 450         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
 451         if (err)
 452                 return err;
 453
 454         err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
 455         if (err)
 456                 return err;
 457
 458         return 0;
 459 };
 460 #else
 461 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 462 {
 463         return 0;
 464 }
 465 #endif
 466
 467 static int __w1_attach_slave_device(struct w1_slave *sl)
 468 {
 469         int err;
 470
 471         sl->dev.parent = &sl->master->dev;
 472         sl->dev.driver = &w1_slave_driver;
 473         sl->dev.bus = &w1_bus_type;
 474         sl->dev.release = &w1_slave_release;
 475
 476         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 477                  "%02x-%012llx",
 478                  (unsigned int) sl->reg_num.family,
 479                  (unsigned long long) sl->reg_num.id);
 480         snprintf(&sl->name[0], sizeof(sl->name),
 481                  "%02x-%012llx",
 482                  (unsigned int) sl->reg_num.family,
 483                  (unsigned long long) sl->reg_num.id);
 484
 485         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);
 486
 487         err = device_register(&sl->dev);
 488         if (err < 0) {
 489                 dev_err(&sl->dev,
 490                         "Device registration [%s] failed. err=%d\n",
 491                         sl->dev.bus_id, err);
 492                 return err;
 493         }
 494
 495         /* Create "name" entry */
 496         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 497         if (err < 0) {
 498                 dev_err(&sl->dev,
 499                         "sysfs file creation for [%s] failed. err=%d\n",
 500                         sl->dev.bus_id, err);
 501                 goto out_unreg;
 502         }
 503
 504         /* Create "id" entry */
 505         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 506         if (err < 0) {
 507                 dev_err(&sl->dev,
 508                         "sysfs file creation for [%s] failed. err=%d\n",
 509                         sl->dev.bus_id, err);
 510                 goto out_rem1;
 511         }
 512
 513         /* if the family driver needs to initialize something... */
 514         if (sl->family->fops && sl->family->fops->add_slave &&
 515             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 516                 dev_err(&sl->dev,
 517                         "sysfs file creation for [%s] failed. err=%d\n",
 518                         sl->dev.bus_id, err);
 519                 goto out_rem2;
 520         }
 521
 522         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 523
 524         return 0;
 525
 526 out_rem2:
 527         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 528 out_rem1:
 529         device_remove_file(&sl->dev, &w1_slave_attr_name);
 530 out_unreg:
 531         device_unregister(&sl->dev);
 532         return err;
 533 }
 534
 535 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 536 {
 537         struct w1_slave *sl;
 538         struct w1_family *f;
 539         int err;
 540         struct w1_netlink_msg msg;
 541
 542         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 543         if (!sl) {
 544                 dev_err(&dev->dev,
 545                          "%s: failed to allocate new slave device.\n",
 546                          __func__);
 547                 return -ENOMEM;
 548         }
 549
 550         memset(sl, 0, sizeof(*sl));
 551
 552         sl->owner = THIS_MODULE;
 553         sl->master = dev;
 554         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 555
 556         memset(&msg, 0, sizeof(msg));
 557         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 558         atomic_set(&sl->refcnt, 0);
 559         init_completion(&sl->released);
 560
 561         spin_lock(&w1_flock);
 562         f = w1_family_registered(rn->family);
 563         if (!f) {
 564                 f= &w1_default_family;
 565                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 566                           rn->family, rn->family,
 567                           (unsigned long long)rn->id, rn->crc);
 568         }
 569         __w1_family_get(f);
 570         spin_unlock(&w1_flock);
 571
 572         sl->family = f;
 573
 574
 575         err = __w1_attach_slave_device(sl);
 576         if (err < 0) {
 577                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 578                          sl->name);
 579                 w1_family_put(sl->family);
 580                 kfree(sl);
 581                 return err;
 582         }
 583
 584         sl->ttl = dev->slave_ttl;
 585         dev->slave_count++;
 586
 587         memcpy(msg.id.id, rn, sizeof(msg.id));
 588         msg.type = W1_SLAVE_ADD;
 589         w1_netlink_send(dev, &msg);
 590
 591         return 0;
 592 }
 593
 594 static void w1_slave_detach(struct w1_slave *sl)
 595 {
 596         struct w1_netlink_msg msg;
 597
 598         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 599
 600         list_del(&sl->w1_slave_entry);
 601
 602         if (sl->family->fops && sl->family->fops->remove_slave)
 603                 sl->family->fops->remove_slave(sl);
 604
 605         memset(&msg, 0, sizeof(msg));
 606         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 607         msg.type = W1_SLAVE_REMOVE;
 608         w1_netlink_send(sl->master, &msg);
 609
 610         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 611         device_remove_file(&sl->dev, &w1_slave_attr_name);
 612         device_unregister(&sl->dev);
 613
 614         wait_for_completion(&sl->released);
 615         kfree(sl);
 616 }
 617
 618 static struct w1_master *w1_search_master(void *data)
 619 {
 620         struct w1_master *dev;
 621         int found = 0;
 622
 623         down(&w1_mlock);
 624         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 625                 if (dev->bus_master->data == data) {
 626                         found = 1;
 627                         atomic_inc(&dev->refcnt);
 628                         break;
 629                 }
 630         }
 631         up(&w1_mlock);
 632
 633         return (found)?dev:NULL;
 634 }
 635
 636 struct w1_master *w1_search_master_id(u32 id)
 637 {
 638         struct w1_master *dev;
 639         int found = 0;
 640
 641         down(&w1_mlock);
 642         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 643                 if (dev->id == id) {
 644                         found = 1;
 645                         atomic_inc(&dev->refcnt);
 646                         break;
 647                 }
 648         }
 649         up(&w1_mlock);
 650
 651         return (found)?dev:NULL;
 652 }
 653
 654 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 655 {
 656         struct w1_master *dev;
 657         struct w1_slave *sl = NULL;
 658         int found = 0;
 659
 660         down(&w1_mlock);
 661         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 662                 down(&dev->mutex);
 663                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 664                         if (sl->reg_num.family == id->family &&
 665                                         sl->reg_num.id == id->id &&
 666                                         sl->reg_num.crc == id->crc) {
 667                                 found = 1;
 668                                 atomic_inc(&dev->refcnt);
 669                                 atomic_inc(&sl->refcnt);
 670                                 break;
 671                         }
 672                 }
 673                 up(&dev->mutex);
 674
 675                 if (found)
 676                         break;
 677         }
 678         up(&w1_mlock);
 679
 680         return (found)?sl:NULL;
 681 }
 682
 683 void w1_reconnect_slaves(struct w1_family *f)
 684 {
 685         struct w1_master *dev;
 686
 687         down(&w1_mlock);
 688         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 689                 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 690                                 dev->name, f->fid);
 691                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 692         }
 693         up(&w1_mlock);
 694 }
 695
 696 static void w1_slave_found(void *data, u64 rn)
 697 {
 698         int slave_count;
 699         struct w1_slave *sl;
 700         struct list_head *ent;
 701         struct w1_reg_num *tmp;
 702         int family_found = 0;
 703         struct w1_master *dev;
 704         u64 rn_le = cpu_to_le64(rn);
 705
 706         dev = w1_search_master(data);
 707         if (!dev) {
 708                 printk(KERN_ERR "Failed to find w1 master device for data %p, "
 709                        "it is impossible.\n", data);
 710                 return;
 711         }
 712
 713         tmp = (struct w1_reg_num *) &rn;
 714
 715         slave_count = 0;
 716         list_for_each(ent, &dev->slist) {
 717
 718                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 719
 720                 if (sl->reg_num.family == tmp->family &&
 721                     sl->reg_num.id == tmp->id &&
 722                     sl->reg_num.crc == tmp->crc) {
 723                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 724                         break;
 725                 } else if (sl->reg_num.family == tmp->family) {
 726                         family_found = 1;
 727                         break;
 728                 }
 729
 730                 slave_count++;
 731         }
 732
 733         if (slave_count == dev->slave_count &&
 734                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 735                 w1_attach_slave_device(dev, tmp);
 736         }
 737
 738         atomic_dec(&dev->refcnt);
 739 }
 740
 741 /**
 742  * Performs a ROM Search & registers any devices found.
 743  * The 1-wire search is a simple binary tree search.
 744  * For each bit of the address, we read two bits and write one bit.
 745  * The bit written will put to sleep all devies that don't match that bit.
 746  * When the two reads differ, the direction choice is obvious.
 747  * When both bits are 0, we must choose a path to take.
 748  * When we can scan all 64 bits without having to choose a path, we are done.
 749  *
 750  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 751  *
 752  * @dev        The master device to search
 753  * @cb         Function to call when a device is found
 754  */
 755 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 756 {
 757         u64 last_rn, rn, tmp64;
 758         int i, slave_count = 0;
 759         int last_zero, last_device;
 760         int search_bit, desc_bit;
 761         u8  triplet_ret = 0;
 762
 763         search_bit = 0;
 764         rn = last_rn = 0;
 765         last_device = 0;
 766         last_zero = -1;
 767
 768         desc_bit = 64;
 769
 770         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 771                 last_rn = rn;
 772                 rn = 0;
 773
 774                 /*
 775                  * Reset bus and all 1-wire device state machines
 776                  * so they can respond to our requests.
 777                  *
 778                  * Return 0 - device(s) present, 1 - no devices present.
 779                  */
 780                 if (w1_reset_bus(dev)) {
 781                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 782                         break;
 783                 }
 784
 785                 /* Start the search */
 786                 w1_write_8(dev, search_type);
 787                 for (i = 0; i < 64; ++i) {
 788                         /* Determine the direction/search bit */
 789                         if (i == desc_bit)
 790                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 791                         else if (i > desc_bit)
 792                                 search_bit = 0;   /* take the 0 path on the next branch */
 793                         else
 794                                 search_bit = ((last_rn >> i) & 0x1);
 795
 796                         /** Read two bits and write one bit */
 797                         triplet_ret = w1_triplet(dev, search_bit);
 798
 799                         /* quit if no device responded */
 800                         if ( (triplet_ret & 0x03) == 0x03 )
 801                                 break;
 802
 803                         /* If both directions were valid, and we took the 0 path... */
 804                         if (triplet_ret == 0)
 805                                 last_zero = i;
 806
 807                         /* extract the direction taken & update the device number */
 808                         tmp64 = (triplet_ret >> 2);
 809                         rn |= (tmp64 << i);
 810                 }
 811
 812                 if ( (triplet_ret & 0x03) != 0x03 ) {
 813                         if ( (desc_bit == last_zero) || (last_zero < 0))
 814                                 last_device = 1;
 815                         desc_bit = last_zero;
 816                         cb(dev->bus_master->data, rn);
 817                 }
 818         }
 819 }
 820
 821 static int w1_control(void *data)
 822 {
 823         struct w1_slave *sl, *sln;
 824         struct w1_master *dev, *n;
 825         int have_to_wait = 0;
 826
 827         while (!kthread_should_stop() || have_to_wait) {
 828                 have_to_wait = 0;
 829
 830                 try_to_freeze();
 831                 msleep_interruptible(w1_control_timeout * 1000);
 832
 833                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 834                         if (!kthread_should_stop() && !dev->flags)
 835                                 continue;
 836                         /*
 837                          * Little race: we can create thread but not set the flag.
 838                          * Get a chance for external process to set flag up.
 839                          */
 840                         if (!dev->initialized) {
 841                                 have_to_wait = 1;
 842                                 continue;
 843                         }
 844
 845                         if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 846                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 847
 848                                 down(&w1_mlock);
 849                                 list_del(&dev->w1_master_entry);
 850                                 up(&w1_mlock);
 851
 852                                 down(&dev->mutex);
 853                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 854                                         w1_slave_detach(sl);
 855                                 }
 856                                 w1_destroy_master_attributes(dev);
 857                                 up(&dev->mutex);
 858                                 atomic_dec(&dev->refcnt);
 859                                 continue;
 860                         }
 861
 862                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 863                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 864                                 down(&dev->mutex);
 865                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 866                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 867                                                 struct w1_reg_num rn;
 868
 869                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 870                                                 w1_slave_detach(sl);
 871
 872                                                 w1_attach_slave_device(dev, &rn);
 873                                         }
 874                                 }
 875                                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name);
 876                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 877                                 up(&dev->mutex);
 878                         }
 879                 }
 880         }
 881
 882         return 0;
 883 }
 884
 885 void w1_search_process(struct w1_master *dev, u8 search_type)
 886 {
 887         struct w1_slave *sl, *sln;
 888
 889         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 890                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 891
 892         w1_search_devices(dev, search_type, w1_slave_found);
 893
 894         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 895                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 896                         w1_slave_detach(sl);
 897
 898                         dev->slave_count--;
 899                 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 900                         sl->ttl = dev->slave_ttl;
 901         }
 902
 903         if (dev->search_count > 0)
 904                 dev->search_count--;
 905 }
 906
 907 int w1_process(void *data)
 908 {
 909         struct w1_master *dev = (struct w1_master *) data;
 910
 911         while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 912                 try_to_freeze();
 913                 msleep_interruptible(w1_timeout * 1000);
 914
 915                 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 916                         break;
 917
 918                 if (!dev->initialized)
 919                         continue;
 920
 921                 if (dev->search_count == 0)
 922                         continue;
 923
 924                 if (down_interruptible(&dev->mutex))
 925                         continue;
 926
 927                 w1_search_process(dev, W1_SEARCH);
 928
 929                 up(&dev->mutex);
 930         }
 931
 932         atomic_dec(&dev->refcnt);
 933
 934         return 0;
 935 }
 936
 937 static int w1_init(void)
 938 {
 939         int retval;
 940
 941         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 942
 943         w1_init_netlink();
 944
 945         retval = bus_register(&w1_bus_type);
 946         if (retval) {
 947                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 948                 goto err_out_exit_init;
 949         }
 950
 951         retval = driver_register(&w1_master_driver);
 952         if (retval) {
 953                 printk(KERN_ERR
 954                         "Failed to register master driver. err=%d.\n",
 955                         retval);
 956                 goto err_out_bus_unregister;
 957         }
 958
 959         retval = driver_register(&w1_slave_driver);
 960         if (retval) {
 961                 printk(KERN_ERR
 962                         "Failed to register master driver. err=%d.\n",
 963                         retval);
 964                 goto err_out_master_unregister;
 965         }
 966
 967         w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
 968         if (IS_ERR(w1_control_thread)) {
 969                 retval = PTR_ERR(w1_control_thread);
 970                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 971                         retval);
 972                 goto err_out_slave_unregister;
 973         }
 974
 975         return 0;
 976
 977 err_out_slave_unregister:
 978         driver_unregister(&w1_slave_driver);
 979
 980 err_out_master_unregister:
 981         driver_unregister(&w1_master_driver);
 982
 983 err_out_bus_unregister:
 984         bus_unregister(&w1_bus_type);
 985
 986 err_out_exit_init:
 987         return retval;
 988 }
 989
 990 static void w1_fini(void)
 991 {
 992         struct w1_master *dev;
 993
 994         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 995                 __w1_remove_master_device(dev);
 996
 997         w1_fini_netlink();
 998
 999         kthread_stop(w1_control_thread);
1000
1001         driver_unregister(&w1_slave_driver);
1002         driver_unregister(&w1_master_driver);
1003         bus_unregister(&w1_bus_type);
1004 }
1005
1006 module_init(w1_init);
1007 module_exit(w1_fini);