SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 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(max_slave_count, w1_max_slave_count, int, 0);
  54 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  55
  56 DEFINE_MUTEX(w1_mlock);
  57 LIST_HEAD(w1_masters);
  58
  59 static int w1_master_match(struct device *dev, struct device_driver *drv)
  60 {
  61         return 1;
  62 }
  63
  64 static int w1_master_probe(struct device *dev)
  65 {
  66         return -ENODEV;
  67 }
  68
  69 static void w1_master_release(struct device *dev)
  70 {
  71         struct w1_master *md = dev_to_w1_master(dev);
  72
  73         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  74         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  75         kfree(md);
  76 }
  77
  78 static void w1_slave_release(struct device *dev)
  79 {
  80         struct w1_slave *sl = dev_to_w1_slave(dev);
  81
  82         printk("%s: Releasing %s.\n", __func__, sl->name);
  83
  84         while (atomic_read(&sl->refcnt)) {
  85                 printk("Waiting for %s to become free: refcnt=%d.\n",
  86                                 sl->name, atomic_read(&sl->refcnt));
  87                 if (msleep_interruptible(1000))
  88                         flush_signals(current);
  89         }
  90
  91         w1_family_put(sl->family);
  92         sl->master->slave_count--;
  93
  94         complete(&sl->released);
  95 }
  96
  97 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
  98 {
  99         struct w1_slave *sl = dev_to_w1_slave(dev);
 100
 101         return sprintf(buf, "%s\n", sl->name);
 102 }
 103
 104 static ssize_t w1_slave_read_id(struct kobject *kobj,
 105                                 struct bin_attribute *bin_attr,
 106                                 char *buf, loff_t off, size_t count)
 107 {
 108         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 109
 110         if (off > 8) {
 111                 count = 0;
 112         } else {
 113                 if (off + count > 8)
 114                         count = 8 - off;
 115
 116                 memcpy(buf, (u8 *)&sl->reg_num, count);
 117         }
 118
 119         return count;
 120 }
 121
 122 static struct device_attribute w1_slave_attr_name =
 123         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 124
 125 static struct bin_attribute w1_slave_attr_bin_id = {
 126       .attr = {
 127               .name = "id",
 128               .mode = S_IRUGO,
 129       },
 130       .size = 8,
 131       .read = w1_slave_read_id,
 132 };
 133
 134 /* Default family */
 135
 136 static ssize_t w1_default_write(struct kobject *kobj,
 137                                 struct bin_attribute *bin_attr,
 138                                 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,
 156                                struct bin_attribute *bin_attr,
 157                                char *buf, loff_t off, size_t count)
 158 {
 159         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 160
 161         mutex_lock(&sl->master->mutex);
 162         w1_read_block(sl->master, buf, count);
 163         mutex_unlock(&sl->master->mutex);
 164         return count;
 165 }
 166
 167 static struct bin_attribute w1_default_attr = {
 168       .attr = {
 169               .name = "rw",
 170               .mode = S_IRUGO | S_IWUSR,
 171       },
 172       .size = PAGE_SIZE,
 173       .read = w1_default_read,
 174       .write = w1_default_write,
 175 };
 176
 177 static int w1_default_add_slave(struct w1_slave *sl)
 178 {
 179         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 180 }
 181
 182 static void w1_default_remove_slave(struct w1_slave *sl)
 183 {
 184         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 185 }
 186
 187 static struct w1_family_ops w1_default_fops = {
 188         .add_slave      = w1_default_add_slave,
 189         .remove_slave   = w1_default_remove_slave,
 190 };
 191
 192 static struct w1_family w1_default_family = {
 193         .fops = &w1_default_fops,
 194 };
 195
 196 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 197
 198 static struct bus_type w1_bus_type = {
 199         .name = "w1",
 200         .match = w1_master_match,
 201         .uevent = w1_uevent,
 202 };
 203
 204 struct device_driver w1_master_driver = {
 205         .name = "w1_master_driver",
 206         .bus = &w1_bus_type,
 207         .probe = w1_master_probe,
 208 };
 209
 210 struct device w1_master_device = {
 211         .parent = NULL,
 212         .bus = &w1_bus_type,
 213         .bus_id = "w1 bus master",
 214         .driver = &w1_master_driver,
 215         .release = &w1_master_release
 216 };
 217
 218 static struct device_driver w1_slave_driver = {
 219         .name = "w1_slave_driver",
 220         .bus = &w1_bus_type,
 221 };
 222
 223 #if 0
 224 struct device w1_slave_device = {
 225         .parent = NULL,
 226         .bus = &w1_bus_type,
 227         .bus_id = "w1 bus slave",
 228         .driver = &w1_slave_driver,
 229         .release = &w1_slave_release
 230 };
 231 #endif  /*  0  */
 232
 233 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 234 {
 235         struct w1_master *md = dev_to_w1_master(dev);
 236         ssize_t count;
 237
 238         mutex_lock(&md->mutex);
 239         count = sprintf(buf, "%s\n", md->name);
 240         mutex_unlock(&md->mutex);
 241
 242         return count;
 243 }
 244
 245 static ssize_t w1_master_attribute_store_search(struct device * dev,
 246                                                 struct device_attribute *attr,
 247                                                 const char * buf, size_t count)
 248 {
 249         struct w1_master *md = dev_to_w1_master(dev);
 250
 251         mutex_lock(&md->mutex);
 252         md->search_count = simple_strtol(buf, NULL, 0);
 253         mutex_unlock(&md->mutex);
 254         wake_up_process(md->thread);
 255
 256         return count;
 257 }
 258
 259 static ssize_t w1_master_attribute_show_search(struct device *dev,
 260                                                struct device_attribute *attr,
 261                                                char *buf)
 262 {
 263         struct w1_master *md = dev_to_w1_master(dev);
 264         ssize_t count;
 265
 266         mutex_lock(&md->mutex);
 267         count = sprintf(buf, "%d\n", md->search_count);
 268         mutex_unlock(&md->mutex);
 269
 270         return count;
 271 }
 272
 273 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 274 {
 275         struct w1_master *md = dev_to_w1_master(dev);
 276         ssize_t count;
 277
 278         mutex_lock(&md->mutex);
 279         count = sprintf(buf, "0x%p\n", md->bus_master);
 280         mutex_unlock(&md->mutex);
 281         return count;
 282 }
 283
 284 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 285 {
 286         ssize_t count;
 287         count = sprintf(buf, "%d\n", w1_timeout);
 288         return count;
 289 }
 290
 291 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 292 {
 293         struct w1_master *md = dev_to_w1_master(dev);
 294         ssize_t count;
 295
 296         mutex_lock(&md->mutex);
 297         count = sprintf(buf, "%d\n", md->max_slave_count);
 298         mutex_unlock(&md->mutex);
 299         return count;
 300 }
 301
 302 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 303 {
 304         struct w1_master *md = dev_to_w1_master(dev);
 305         ssize_t count;
 306
 307         mutex_lock(&md->mutex);
 308         count = sprintf(buf, "%lu\n", md->attempts);
 309         mutex_unlock(&md->mutex);
 310         return count;
 311 }
 312
 313 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 314 {
 315         struct w1_master *md = dev_to_w1_master(dev);
 316         ssize_t count;
 317
 318         mutex_lock(&md->mutex);
 319         count = sprintf(buf, "%d\n", md->slave_count);
 320         mutex_unlock(&md->mutex);
 321         return count;
 322 }
 323
 324 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 325 {
 326         struct w1_master *md = dev_to_w1_master(dev);
 327         int c = PAGE_SIZE;
 328
 329         mutex_lock(&md->mutex);
 330
 331         if (md->slave_count == 0)
 332                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 333         else {
 334                 struct list_head *ent, *n;
 335                 struct w1_slave *sl;
 336
 337                 list_for_each_safe(ent, n, &md->slist) {
 338                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 339
 340                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 341                 }
 342         }
 343
 344         mutex_unlock(&md->mutex);
 345
 346         return PAGE_SIZE - c;
 347 }
 348
 349 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 350         struct device_attribute w1_master_attribute_##_name =   \
 351                 __ATTR(w1_master_##_name, _mode,                \
 352                        w1_master_attribute_show_##_name, NULL)
 353
 354 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 355         struct device_attribute w1_master_attribute_##_name =   \
 356                 __ATTR(w1_master_##_name, _mode,                \
 357                        w1_master_attribute_show_##_name,        \
 358                        w1_master_attribute_store_##_name)
 359
 360 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 361 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 362 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 363 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 364 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 365 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 366 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 367 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 368
 369 static struct attribute *w1_master_default_attrs[] = {
 370         &w1_master_attribute_name.attr,
 371         &w1_master_attribute_slaves.attr,
 372         &w1_master_attribute_slave_count.attr,
 373         &w1_master_attribute_max_slave_count.attr,
 374         &w1_master_attribute_attempts.attr,
 375         &w1_master_attribute_timeout.attr,
 376         &w1_master_attribute_pointer.attr,
 377         &w1_master_attribute_search.attr,
 378         NULL
 379 };
 380
 381 static struct attribute_group w1_master_defattr_group = {
 382         .attrs = w1_master_default_attrs,
 383 };
 384
 385 int w1_create_master_attributes(struct w1_master *master)
 386 {
 387         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 388 }
 389
 390 void w1_destroy_master_attributes(struct w1_master *master)
 391 {
 392         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 393 }
 394
 395 #ifdef CONFIG_HOTPLUG
 396 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 397 {
 398         struct w1_master *md = NULL;
 399         struct w1_slave *sl = NULL;
 400         char *event_owner, *name;
 401         int err;
 402
 403         if (dev->driver == &w1_master_driver) {
 404                 md = container_of(dev, struct w1_master, dev);
 405                 event_owner = "master";
 406                 name = md->name;
 407         } else if (dev->driver == &w1_slave_driver) {
 408                 sl = container_of(dev, struct w1_slave, dev);
 409                 event_owner = "slave";
 410                 name = sl->name;
 411         } else {
 412                 dev_dbg(dev, "Unknown event.\n");
 413                 return -EINVAL;
 414         }
 415
 416         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 417                         event_owner, name, dev->bus_id);
 418
 419         if (dev->driver != &w1_slave_driver || !sl)
 420                 return 0;
 421
 422         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 423         if (err)
 424                 return err;
 425
 426         err = add_uevent_var(env, "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, struct kobj_uevent_env *env)
 435 {
 436         return 0;
 437 }
 438 #endif
 439
 440 static int __w1_attach_slave_device(struct w1_slave *sl)
 441 {
 442         int err;
 443
 444         sl->dev.parent = &sl->master->dev;
 445         sl->dev.driver = &w1_slave_driver;
 446         sl->dev.bus = &w1_bus_type;
 447         sl->dev.release = &w1_slave_release;
 448
 449         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 450                  "%02x-%012llx",
 451                  (unsigned int) sl->reg_num.family,
 452                  (unsigned long long) sl->reg_num.id);
 453         snprintf(&sl->name[0], sizeof(sl->name),
 454                  "%02x-%012llx",
 455                  (unsigned int) sl->reg_num.family,
 456                  (unsigned long long) sl->reg_num.id);
 457
 458         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 459                 &sl->dev.bus_id[0], sl);
 460
 461         err = device_register(&sl->dev);
 462         if (err < 0) {
 463                 dev_err(&sl->dev,
 464                         "Device registration [%s] failed. err=%d\n",
 465                         sl->dev.bus_id, err);
 466                 return err;
 467         }
 468
 469         /* Create "name" entry */
 470         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 471         if (err < 0) {
 472                 dev_err(&sl->dev,
 473                         "sysfs file creation for [%s] failed. err=%d\n",
 474                         sl->dev.bus_id, err);
 475                 goto out_unreg;
 476         }
 477
 478         /* Create "id" entry */
 479         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 480         if (err < 0) {
 481                 dev_err(&sl->dev,
 482                         "sysfs file creation for [%s] failed. err=%d\n",
 483                         sl->dev.bus_id, err);
 484                 goto out_rem1;
 485         }
 486
 487         /* if the family driver needs to initialize something... */
 488         if (sl->family->fops && sl->family->fops->add_slave &&
 489             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 490                 dev_err(&sl->dev,
 491                         "sysfs file creation for [%s] failed. err=%d\n",
 492                         sl->dev.bus_id, err);
 493                 goto out_rem2;
 494         }
 495
 496         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 497
 498         return 0;
 499
 500 out_rem2:
 501         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 502 out_rem1:
 503         device_remove_file(&sl->dev, &w1_slave_attr_name);
 504 out_unreg:
 505         device_unregister(&sl->dev);
 506         return err;
 507 }
 508
 509 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 510 {
 511         struct w1_slave *sl;
 512         struct w1_family *f;
 513         int err;
 514         struct w1_netlink_msg msg;
 515
 516         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 517         if (!sl) {
 518                 dev_err(&dev->dev,
 519                          "%s: failed to allocate new slave device.\n",
 520                          __func__);
 521                 return -ENOMEM;
 522         }
 523
 524
 525         sl->owner = THIS_MODULE;
 526         sl->master = dev;
 527         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 528
 529         memset(&msg, 0, sizeof(msg));
 530         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 531         atomic_set(&sl->refcnt, 0);
 532         init_completion(&sl->released);
 533
 534         spin_lock(&w1_flock);
 535         f = w1_family_registered(rn->family);
 536         if (!f) {
 537                 f= &w1_default_family;
 538                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 539                           rn->family, rn->family,
 540                           (unsigned long long)rn->id, rn->crc);
 541         }
 542         __w1_family_get(f);
 543         spin_unlock(&w1_flock);
 544
 545         sl->family = f;
 546
 547
 548         err = __w1_attach_slave_device(sl);
 549         if (err < 0) {
 550                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 551                          sl->name);
 552                 w1_family_put(sl->family);
 553                 kfree(sl);
 554                 return err;
 555         }
 556
 557         sl->ttl = dev->slave_ttl;
 558         dev->slave_count++;
 559
 560         memcpy(msg.id.id, rn, sizeof(msg.id));
 561         msg.type = W1_SLAVE_ADD;
 562         w1_netlink_send(dev, &msg);
 563
 564         return 0;
 565 }
 566
 567 void w1_slave_detach(struct w1_slave *sl)
 568 {
 569         struct w1_netlink_msg msg;
 570
 571         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 572
 573         list_del(&sl->w1_slave_entry);
 574
 575         if (sl->family->fops && sl->family->fops->remove_slave)
 576                 sl->family->fops->remove_slave(sl);
 577
 578         memset(&msg, 0, sizeof(msg));
 579         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 580         msg.type = W1_SLAVE_REMOVE;
 581         w1_netlink_send(sl->master, &msg);
 582
 583         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 584         device_remove_file(&sl->dev, &w1_slave_attr_name);
 585         device_unregister(&sl->dev);
 586
 587         wait_for_completion(&sl->released);
 588         kfree(sl);
 589 }
 590
 591 struct w1_master *w1_search_master_id(u32 id)
 592 {
 593         struct w1_master *dev;
 594         int found = 0;
 595
 596         mutex_lock(&w1_mlock);
 597         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 598                 if (dev->id == id) {
 599                         found = 1;
 600                         atomic_inc(&dev->refcnt);
 601                         break;
 602                 }
 603         }
 604         mutex_unlock(&w1_mlock);
 605
 606         return (found)?dev:NULL;
 607 }
 608
 609 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 610 {
 611         struct w1_master *dev;
 612         struct w1_slave *sl = NULL;
 613         int found = 0;
 614
 615         mutex_lock(&w1_mlock);
 616         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 617                 mutex_lock(&dev->mutex);
 618                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 619                         if (sl->reg_num.family == id->family &&
 620                                         sl->reg_num.id == id->id &&
 621                                         sl->reg_num.crc == id->crc) {
 622                                 found = 1;
 623                                 atomic_inc(&dev->refcnt);
 624                                 atomic_inc(&sl->refcnt);
 625                                 break;
 626                         }
 627                 }
 628                 mutex_unlock(&dev->mutex);
 629
 630                 if (found)
 631                         break;
 632         }
 633         mutex_unlock(&w1_mlock);
 634
 635         return (found)?sl:NULL;
 636 }
 637
 638 void w1_reconnect_slaves(struct w1_family *f, int attach)
 639 {
 640         struct w1_slave *sl, *sln;
 641         struct w1_master *dev;
 642
 643         mutex_lock(&w1_mlock);
 644         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 645                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 646                         "for family %02x.\n", dev->name, f->fid);
 647                 mutex_lock(&dev->mutex);
 648                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 649                         /* If it is a new family, slaves with the default
 650                          * family driver and are that family will be
 651                          * connected.  If the family is going away, devices
 652                          * matching that family are reconneced.
 653                          */
 654                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 655                                 && sl->reg_num.family == f->fid) ||
 656                                 (!attach && sl->family->fid == f->fid)) {
 657                                 struct w1_reg_num rn;
 658
 659                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 660                                 w1_slave_detach(sl);
 661
 662                                 w1_attach_slave_device(dev, &rn);
 663                         }
 664                 }
 665                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 666                         "has been finished.\n", dev->name);
 667                 mutex_unlock(&dev->mutex);
 668         }
 669         mutex_unlock(&w1_mlock);
 670 }
 671
 672 static void w1_slave_found(struct w1_master *dev, u64 rn)
 673 {
 674         int slave_count;
 675         struct w1_slave *sl;
 676         struct list_head *ent;
 677         struct w1_reg_num *tmp;
 678         u64 rn_le = cpu_to_le64(rn);
 679
 680         atomic_inc(&dev->refcnt);
 681
 682         tmp = (struct w1_reg_num *) &rn;
 683
 684         slave_count = 0;
 685         list_for_each(ent, &dev->slist) {
 686
 687                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 688
 689                 if (sl->reg_num.family == tmp->family &&
 690                     sl->reg_num.id == tmp->id &&
 691                     sl->reg_num.crc == tmp->crc) {
 692                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 693                         break;
 694                 }
 695
 696                 slave_count++;
 697         }
 698
 699         if (slave_count == dev->slave_count &&
 700                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 701                 w1_attach_slave_device(dev, tmp);
 702         }
 703
 704         atomic_dec(&dev->refcnt);
 705 }
 706
 707 /**
 708  * Performs a ROM Search & registers any devices found.
 709  * The 1-wire search is a simple binary tree search.
 710  * For each bit of the address, we read two bits and write one bit.
 711  * The bit written will put to sleep all devies that don't match that bit.
 712  * When the two reads differ, the direction choice is obvious.
 713  * When both bits are 0, we must choose a path to take.
 714  * When we can scan all 64 bits without having to choose a path, we are done.
 715  *
 716  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 717  *
 718  * @dev        The master device to search
 719  * @cb         Function to call when a device is found
 720  */
 721 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 722 {
 723         u64 last_rn, rn, tmp64;
 724         int i, slave_count = 0;
 725         int last_zero, last_device;
 726         int search_bit, desc_bit;
 727         u8  triplet_ret = 0;
 728
 729         search_bit = 0;
 730         rn = last_rn = 0;
 731         last_device = 0;
 732         last_zero = -1;
 733
 734         desc_bit = 64;
 735
 736         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 737                 last_rn = rn;
 738                 rn = 0;
 739
 740                 /*
 741                  * Reset bus and all 1-wire device state machines
 742                  * so they can respond to our requests.
 743                  *
 744                  * Return 0 - device(s) present, 1 - no devices present.
 745                  */
 746                 if (w1_reset_bus(dev)) {
 747                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 748                         break;
 749                 }
 750
 751                 /* Start the search */
 752                 w1_write_8(dev, search_type);
 753                 for (i = 0; i < 64; ++i) {
 754                         /* Determine the direction/search bit */
 755                         if (i == desc_bit)
 756                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 757                         else if (i > desc_bit)
 758                                 search_bit = 0;   /* take the 0 path on the next branch */
 759                         else
 760                                 search_bit = ((last_rn >> i) & 0x1);
 761
 762                         /** Read two bits and write one bit */
 763                         triplet_ret = w1_triplet(dev, search_bit);
 764
 765                         /* quit if no device responded */
 766                         if ( (triplet_ret & 0x03) == 0x03 )
 767                                 break;
 768
 769                         /* If both directions were valid, and we took the 0 path... */
 770                         if (triplet_ret == 0)
 771                                 last_zero = i;
 772
 773                         /* extract the direction taken & update the device number */
 774                         tmp64 = (triplet_ret >> 2);
 775                         rn |= (tmp64 << i);
 776
 777                         if (kthread_should_stop()) {
 778                                 printk(KERN_INFO "Abort w1_search (exiting)\n");
 779                                 return;
 780                         }
 781                 }
 782
 783                 if ( (triplet_ret & 0x03) != 0x03 ) {
 784                         if ( (desc_bit == last_zero) || (last_zero < 0))
 785                                 last_device = 1;
 786                         desc_bit = last_zero;
 787                         cb(dev, rn);
 788                 }
 789         }
 790 }
 791
 792 void w1_search_process(struct w1_master *dev, u8 search_type)
 793 {
 794         struct w1_slave *sl, *sln;
 795
 796         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 797                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 798
 799         w1_search_devices(dev, search_type, w1_slave_found);
 800
 801         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 802                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
 803                         w1_slave_detach(sl);
 804                 else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 805                         sl->ttl = dev->slave_ttl;
 806         }
 807
 808         if (dev->search_count > 0)
 809                 dev->search_count--;
 810 }
 811
 812 int w1_process(void *data)
 813 {
 814         struct w1_master *dev = (struct w1_master *) data;
 815         /* As long as w1_timeout is only set by a module parameter the sleep
 816          * time can be calculated in jiffies once.
 817          */
 818         const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
 819
 820         while (!kthread_should_stop()) {
 821                 if (dev->search_count) {
 822                         mutex_lock(&dev->mutex);
 823                         w1_search_process(dev, W1_SEARCH);
 824                         mutex_unlock(&dev->mutex);
 825                 }
 826
 827                 try_to_freeze();
 828                 __set_current_state(TASK_INTERRUPTIBLE);
 829
 830                 if (kthread_should_stop())
 831                         break;
 832
 833                 /* Only sleep when the search is active. */
 834                 if (dev->search_count)
 835                         schedule_timeout(jtime);
 836                 else
 837                         schedule();
 838         }
 839
 840         atomic_dec(&dev->refcnt);
 841
 842         return 0;
 843 }
 844
 845 static int w1_init(void)
 846 {
 847         int retval;
 848
 849         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 850
 851         w1_init_netlink();
 852
 853         retval = bus_register(&w1_bus_type);
 854         if (retval) {
 855                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 856                 goto err_out_exit_init;
 857         }
 858
 859         retval = driver_register(&w1_master_driver);
 860         if (retval) {
 861                 printk(KERN_ERR
 862                         "Failed to register master driver. err=%d.\n",
 863                         retval);
 864                 goto err_out_bus_unregister;
 865         }
 866
 867         retval = driver_register(&w1_slave_driver);
 868         if (retval) {
 869                 printk(KERN_ERR
 870                         "Failed to register master driver. err=%d.\n",
 871                         retval);
 872                 goto err_out_master_unregister;
 873         }
 874
 875         return 0;
 876
 877 #if 0
 878 /* For undoing the slave register if there was a step after it. */
 879 err_out_slave_unregister:
 880         driver_unregister(&w1_slave_driver);
 881 #endif
 882
 883 err_out_master_unregister:
 884         driver_unregister(&w1_master_driver);
 885
 886 err_out_bus_unregister:
 887         bus_unregister(&w1_bus_type);
 888
 889 err_out_exit_init:
 890         return retval;
 891 }
 892
 893 static void w1_fini(void)
 894 {
 895         struct w1_master *dev;
 896
 897         /* Set netlink removal messages and some cleanup */
 898         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 899                 __w1_remove_master_device(dev);
 900
 901         w1_fini_netlink();
 902
 903         driver_unregister(&w1_slave_driver);
 904         driver_unregister(&w1_master_driver);
 905         bus_unregister(&w1_bus_type);
 906 }
 907
 908 module_init(w1_init);
 909 module_exit(w1_fini);