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
  34 #include <asm/atomic.h>
  35
  36 #include "w1.h"
  37 #include "w1_io.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 int w1_max_slave_count = 10;
  49 int w1_max_slave_ttl = 10;
  50
  51 module_param_named(timeout, w1_timeout, int, 0);
  52 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  53 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  54
  55 DEFINE_SPINLOCK(w1_mlock);
  56 LIST_HEAD(w1_masters);
  57
  58 static pid_t control_thread;
  59 static int control_needs_exit;
  60 static DECLARE_COMPLETION(w1_control_complete);
  61
  62 /* stuff for the default family */
  63 static ssize_t w1_famdefault_read_name(struct device *dev, struct device_attribute *attr, char *buf)
  64 {
  65         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  66         return(sprintf(buf, "%s\n", sl->name));
  67 }
  68 static struct w1_family_ops w1_default_fops = {
  69         .rname = &w1_famdefault_read_name,
  70 };
  71 static struct w1_family w1_default_family = {
  72         .fops = &w1_default_fops,
  73 };
  74
  75 static int w1_master_match(struct device *dev, struct device_driver *drv)
  76 {
  77         return 1;
  78 }
  79
  80 static int w1_master_probe(struct device *dev)
  81 {
  82         return -ENODEV;
  83 }
  84
  85 static int w1_master_remove(struct device *dev)
  86 {
  87         return 0;
  88 }
  89
  90 static void w1_master_release(struct device *dev)
  91 {
  92         struct w1_master *md = dev_to_w1_master(dev);
  93         complete(&md->dev_released);
  94 }
  95
  96 static void w1_slave_release(struct device *dev)
  97 {
  98         struct w1_slave *sl = dev_to_w1_slave(dev);
  99         complete(&sl->dev_released);
 100 }
 101
 102 static ssize_t w1_default_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 103 {
 104         return sprintf(buf, "No family registered.\n");
 105 }
 106
 107 static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off,
 108                      size_t count)
 109 {
 110         return sprintf(buf, "No family registered.\n");
 111 }
 112
 113 static struct device_attribute w1_slave_attribute =
 114         __ATTR(name, S_IRUGO, w1_default_read_name, NULL);
 115
 116 static struct bin_attribute w1_slave_bin_attribute = {
 117         .attr = {
 118                 .name = "w1_slave",
 119                 .mode = S_IRUGO,
 120                 .owner = THIS_MODULE,
 121         },
 122         .size = W1_SLAVE_DATA_SIZE,
 123         .read = &w1_default_read_bin,
 124 };
 125
 126 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 127
 128 static struct bus_type w1_bus_type = {
 129         .name = "w1",
 130         .match = w1_master_match,
 131         .hotplug = w1_hotplug,
 132 };
 133
 134 struct device_driver w1_master_driver = {
 135         .name = "w1_master_driver",
 136         .bus = &w1_bus_type,
 137         .probe = w1_master_probe,
 138         .remove = w1_master_remove,
 139 };
 140
 141 struct device w1_master_device = {
 142         .parent = NULL,
 143         .bus = &w1_bus_type,
 144         .bus_id = "w1 bus master",
 145         .driver = &w1_master_driver,
 146         .release = &w1_master_release
 147 };
 148
 149 struct device_driver w1_slave_driver = {
 150         .name = "w1_slave_driver",
 151         .bus = &w1_bus_type,
 152 };
 153
 154 struct device w1_slave_device = {
 155         .parent = NULL,
 156         .bus = &w1_bus_type,
 157         .bus_id = "w1 bus slave",
 158         .driver = &w1_slave_driver,
 159 };
 160
 161 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 162 {
 163         struct w1_master *md = dev_to_w1_master(dev);
 164         ssize_t count;
 165
 166         if (down_interruptible (&md->mutex))
 167                 return -EBUSY;
 168
 169         count = sprintf(buf, "%s\n", md->name);
 170
 171         up(&md->mutex);
 172
 173         return count;
 174 }
 175
 176 static ssize_t w1_master_attribute_store_search(struct device * dev,
 177                                                 struct device_attribute *attr,
 178                                                 const char * buf, size_t count)
 179 {
 180         struct w1_master *md = dev_to_w1_master(dev);
 181
 182         if (down_interruptible (&md->mutex))
 183                 return -EBUSY;
 184
 185         md->search_count = simple_strtol(buf, NULL, 0);
 186
 187         up(&md->mutex);
 188
 189         return count;
 190 }
 191
 192 static ssize_t w1_master_attribute_show_search(struct device *dev,
 193                                                struct device_attribute *attr,
 194                                                char *buf)
 195 {
 196         struct w1_master *md = dev_to_w1_master(dev);
 197         ssize_t count;
 198
 199         if (down_interruptible (&md->mutex))
 200                 return -EBUSY;
 201
 202         count = sprintf(buf, "%d\n", md->search_count);
 203
 204         up(&md->mutex);
 205
 206         return count;
 207 }
 208
 209 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 210 {
 211         struct w1_master *md = dev_to_w1_master(dev);
 212         ssize_t count;
 213
 214         if (down_interruptible(&md->mutex))
 215                 return -EBUSY;
 216
 217         count = sprintf(buf, "0x%p\n", md->bus_master);
 218
 219         up(&md->mutex);
 220         return count;
 221 }
 222
 223 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 224 {
 225         ssize_t count;
 226         count = sprintf(buf, "%d\n", w1_timeout);
 227         return count;
 228 }
 229
 230 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 231 {
 232         struct w1_master *md = dev_to_w1_master(dev);
 233         ssize_t count;
 234
 235         if (down_interruptible(&md->mutex))
 236                 return -EBUSY;
 237
 238         count = sprintf(buf, "%d\n", md->max_slave_count);
 239
 240         up(&md->mutex);
 241         return count;
 242 }
 243
 244 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 245 {
 246         struct w1_master *md = dev_to_w1_master(dev);
 247         ssize_t count;
 248
 249         if (down_interruptible(&md->mutex))
 250                 return -EBUSY;
 251
 252         count = sprintf(buf, "%lu\n", md->attempts);
 253
 254         up(&md->mutex);
 255         return count;
 256 }
 257
 258 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 259 {
 260         struct w1_master *md = dev_to_w1_master(dev);
 261         ssize_t count;
 262
 263         if (down_interruptible(&md->mutex))
 264                 return -EBUSY;
 265
 266         count = sprintf(buf, "%d\n", md->slave_count);
 267
 268         up(&md->mutex);
 269         return count;
 270 }
 271
 272 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 273 {
 274         struct w1_master *md = dev_to_w1_master(dev);
 275         int c = PAGE_SIZE;
 276
 277         if (down_interruptible(&md->mutex))
 278                 return -EBUSY;
 279
 280         if (md->slave_count == 0)
 281                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 282         else {
 283                 struct list_head *ent, *n;
 284                 struct w1_slave *sl;
 285
 286                 list_for_each_safe(ent, n, &md->slist) {
 287                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 288
 289                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 290                 }
 291         }
 292
 293         up(&md->mutex);
 294
 295         return PAGE_SIZE - c;
 296 }
 297
 298 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 299         struct device_attribute w1_master_attribute_##_name =   \
 300                 __ATTR(w1_master_##_name, _mode,                \
 301                        w1_master_attribute_show_##_name, NULL)
 302
 303 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 304         struct device_attribute w1_master_attribute_##_name =   \
 305                 __ATTR(w1_master_##_name, _mode,                \
 306                        w1_master_attribute_show_##_name,        \
 307                        w1_master_attribute_store_##_name)
 308
 309 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 310 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 311 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 312 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 313 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 314 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 315 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 316 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 317
 318 static struct attribute *w1_master_default_attrs[] = {
 319         &w1_master_attribute_name.attr,
 320         &w1_master_attribute_slaves.attr,
 321         &w1_master_attribute_slave_count.attr,
 322         &w1_master_attribute_max_slave_count.attr,
 323         &w1_master_attribute_attempts.attr,
 324         &w1_master_attribute_timeout.attr,
 325         &w1_master_attribute_pointer.attr,
 326         &w1_master_attribute_search.attr,
 327         NULL
 328 };
 329
 330 static struct attribute_group w1_master_defattr_group = {
 331         .attrs = w1_master_default_attrs,
 332 };
 333
 334 int w1_create_master_attributes(struct w1_master *master)
 335 {
 336         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 337 }
 338
 339 void w1_destroy_master_attributes(struct w1_master *master)
 340 {
 341         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 342 }
 343
 344 #ifdef CONFIG_HOTPLUG
 345 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 346 {
 347         struct w1_master *md = NULL;
 348         struct w1_slave *sl = NULL;
 349         char *event_owner, *name;
 350         int err, cur_index=0, cur_len=0;
 351
 352         if (dev->driver == &w1_master_driver) {
 353                 md = container_of(dev, struct w1_master, dev);
 354                 event_owner = "master";
 355                 name = md->name;
 356         } else if (dev->driver == &w1_slave_driver) {
 357                 sl = container_of(dev, struct w1_slave, dev);
 358                 event_owner = "slave";
 359                 name = sl->name;
 360         } else {
 361                 dev_dbg(dev, "Unknown hotplug event.\n");
 362                 return -EINVAL;
 363         }
 364
 365         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
 366
 367         if (dev->driver != &w1_slave_driver || !sl)
 368                 return 0;
 369
 370         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
 371         if (err)
 372                 return err;
 373
 374         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
 375         if (err)
 376                 return err;
 377
 378         return 0;
 379 };
 380 #else
 381 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 382 {
 383         return 0;
 384 }
 385 #endif
 386
 387 static int __w1_attach_slave_device(struct w1_slave *sl)
 388 {
 389         int err;
 390
 391         sl->dev.parent = &sl->master->dev;
 392         sl->dev.driver = &w1_slave_driver;
 393         sl->dev.bus = &w1_bus_type;
 394         sl->dev.release = &w1_slave_release;
 395
 396         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 397                  "%02x-%012llx",
 398                  (unsigned int) sl->reg_num.family,
 399                  (unsigned long long) sl->reg_num.id);
 400         snprintf(&sl->name[0], sizeof(sl->name),
 401                  "%02x-%012llx",
 402                  (unsigned int) sl->reg_num.family,
 403                  (unsigned long long) sl->reg_num.id);
 404
 405         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
 406                 &sl->dev.bus_id[0]);
 407
 408         err = device_register(&sl->dev);
 409         if (err < 0) {
 410                 dev_err(&sl->dev,
 411                         "Device registration [%s] failed. err=%d\n",
 412                         sl->dev.bus_id, err);
 413                 return err;
 414         }
 415
 416         memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
 417         memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
 418
 419         sl->attr_bin.read = sl->family->fops->rbin;
 420         sl->attr_name.show = sl->family->fops->rname;
 421
 422         err = device_create_file(&sl->dev, &sl->attr_name);
 423         if (err < 0) {
 424                 dev_err(&sl->dev,
 425                         "sysfs file creation for [%s] failed. err=%d\n",
 426                         sl->dev.bus_id, err);
 427                 device_unregister(&sl->dev);
 428                 return err;
 429         }
 430
 431         if ( sl->attr_bin.read ) {
 432                 err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
 433                 if (err < 0) {
 434                         dev_err(&sl->dev,
 435                                 "sysfs file creation for [%s] failed. err=%d\n",
 436                                 sl->dev.bus_id, err);
 437                         device_remove_file(&sl->dev, &sl->attr_name);
 438                         device_unregister(&sl->dev);
 439                         return err;
 440                 }
 441         }
 442
 443         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 444
 445         return 0;
 446 }
 447
 448 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 449 {
 450         struct w1_slave *sl;
 451         struct w1_family *f;
 452         int err;
 453         struct w1_netlink_msg msg;
 454
 455         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 456         if (!sl) {
 457                 dev_err(&dev->dev,
 458                          "%s: failed to allocate new slave device.\n",
 459                          __func__);
 460                 return -ENOMEM;
 461         }
 462
 463         memset(sl, 0, sizeof(*sl));
 464
 465         sl->owner = THIS_MODULE;
 466         sl->master = dev;
 467         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 468
 469         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 470         atomic_set(&sl->refcnt, 0);
 471         init_completion(&sl->dev_released);
 472
 473         spin_lock(&w1_flock);
 474         f = w1_family_registered(rn->family);
 475         if (!f) {
 476                 f= &w1_default_family;
 477                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 478                           rn->family, rn->family,
 479                           (unsigned long long)rn->id, rn->crc);
 480         }
 481         __w1_family_get(f);
 482         spin_unlock(&w1_flock);
 483
 484         sl->family = f;
 485
 486
 487         err = __w1_attach_slave_device(sl);
 488         if (err < 0) {
 489                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 490                          sl->name);
 491                 w1_family_put(sl->family);
 492                 kfree(sl);
 493                 return err;
 494         }
 495
 496         sl->ttl = dev->slave_ttl;
 497         dev->slave_count++;
 498
 499         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 500         msg.type = W1_SLAVE_ADD;
 501         w1_netlink_send(dev, &msg);
 502
 503         return 0;
 504 }
 505
 506 static void w1_slave_detach(struct w1_slave *sl)
 507 {
 508         struct w1_netlink_msg msg;
 509
 510         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
 511
 512         while (atomic_read(&sl->refcnt)) {
 513                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 514                                 sl->name, atomic_read(&sl->refcnt));
 515
 516                 if (msleep_interruptible(1000))
 517                         flush_signals(current);
 518         }
 519
 520         if ( sl->attr_bin.read ) {
 521                 sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
 522         }
 523         device_remove_file(&sl->dev, &sl->attr_name);
 524         device_unregister(&sl->dev);
 525         w1_family_put(sl->family);
 526
 527         sl->master->slave_count--;
 528
 529         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 530         msg.type = W1_SLAVE_REMOVE;
 531         w1_netlink_send(sl->master, &msg);
 532 }
 533
 534 static struct w1_master *w1_search_master(unsigned long data)
 535 {
 536         struct w1_master *dev;
 537         int found = 0;
 538
 539         spin_lock_bh(&w1_mlock);
 540         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 541                 if (dev->bus_master->data == data) {
 542                         found = 1;
 543                         atomic_inc(&dev->refcnt);
 544                         break;
 545                 }
 546         }
 547         spin_unlock_bh(&w1_mlock);
 548
 549         return (found)?dev:NULL;
 550 }
 551
 552 void w1_reconnect_slaves(struct w1_family *f)
 553 {
 554         struct w1_master *dev;
 555
 556         spin_lock_bh(&w1_mlock);
 557         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 558                 dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 559                                 dev->name, f->fid);
 560                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 561         }
 562         spin_unlock_bh(&w1_mlock);
 563 }
 564
 565 static void w1_slave_found(unsigned long data, u64 rn)
 566 {
 567         int slave_count;
 568         struct w1_slave *sl;
 569         struct list_head *ent;
 570         struct w1_reg_num *tmp;
 571         int family_found = 0;
 572         struct w1_master *dev;
 573         u64 rn_le = cpu_to_le64(rn);
 574
 575         dev = w1_search_master(data);
 576         if (!dev) {
 577                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 578                                 data);
 579                 return;
 580         }
 581
 582         tmp = (struct w1_reg_num *) &rn;
 583
 584         slave_count = 0;
 585         list_for_each(ent, &dev->slist) {
 586
 587                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 588
 589                 if (sl->reg_num.family == tmp->family &&
 590                     sl->reg_num.id == tmp->id &&
 591                     sl->reg_num.crc == tmp->crc) {
 592                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 593                         break;
 594                 } else if (sl->reg_num.family == tmp->family) {
 595                         family_found = 1;
 596                         break;
 597                 }
 598
 599                 slave_count++;
 600         }
 601
 602         if (slave_count == dev->slave_count &&
 603                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 604                 w1_attach_slave_device(dev, tmp);
 605         }
 606
 607         atomic_dec(&dev->refcnt);
 608 }
 609
 610 /**
 611  * Performs a ROM Search & registers any devices found.
 612  * The 1-wire search is a simple binary tree search.
 613  * For each bit of the address, we read two bits and write one bit.
 614  * The bit written will put to sleep all devies that don't match that bit.
 615  * When the two reads differ, the direction choice is obvious.
 616  * When both bits are 0, we must choose a path to take.
 617  * When we can scan all 64 bits without having to choose a path, we are done.
 618  *
 619  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 620  *
 621  * @dev        The master device to search
 622  * @cb         Function to call when a device is found
 623  */
 624 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
 625 {
 626         u64 last_rn, rn, tmp64;
 627         int i, slave_count = 0;
 628         int last_zero, last_device;
 629         int search_bit, desc_bit;
 630         u8  triplet_ret = 0;
 631
 632         search_bit = 0;
 633         rn = last_rn = 0;
 634         last_device = 0;
 635         last_zero = -1;
 636
 637         desc_bit = 64;
 638
 639         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 640                 last_rn = rn;
 641                 rn = 0;
 642
 643                 /*
 644                  * Reset bus and all 1-wire device state machines
 645                  * so they can respond to our requests.
 646                  *
 647                  * Return 0 - device(s) present, 1 - no devices present.
 648                  */
 649                 if (w1_reset_bus(dev)) {
 650                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 651                         break;
 652                 }
 653
 654                 /* Start the search */
 655                 w1_write_8(dev, W1_SEARCH);
 656                 for (i = 0; i < 64; ++i) {
 657                         /* Determine the direction/search bit */
 658                         if (i == desc_bit)
 659                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 660                         else if (i > desc_bit)
 661                                 search_bit = 0;   /* take the 0 path on the next branch */
 662                         else
 663                                 search_bit = ((last_rn >> i) & 0x1);
 664
 665                         /** Read two bits and write one bit */
 666                         triplet_ret = w1_triplet(dev, search_bit);
 667
 668                         /* quit if no device responded */
 669                         if ( (triplet_ret & 0x03) == 0x03 )
 670                                 break;
 671
 672                         /* If both directions were valid, and we took the 0 path... */
 673                         if (triplet_ret == 0)
 674                                 last_zero = i;
 675
 676                         /* extract the direction taken & update the device number */
 677                         tmp64 = (triplet_ret >> 2);
 678                         rn |= (tmp64 << i);
 679                 }
 680
 681                 if ( (triplet_ret & 0x03) != 0x03 ) {
 682                         if ( (desc_bit == last_zero) || (last_zero < 0))
 683                                 last_device = 1;
 684                         desc_bit = last_zero;
 685                         cb(dev->bus_master->data, rn);
 686                 }
 687         }
 688 }
 689
 690 static int w1_control(void *data)
 691 {
 692         struct w1_slave *sl, *sln;
 693         struct w1_master *dev, *n;
 694         int err, have_to_wait = 0;
 695
 696         daemonize("w1_control");
 697         allow_signal(SIGTERM);
 698
 699         while (!control_needs_exit || have_to_wait) {
 700                 have_to_wait = 0;
 701
 702                 try_to_freeze();
 703                 msleep_interruptible(w1_timeout * 1000);
 704
 705                 if (signal_pending(current))
 706                         flush_signals(current);
 707
 708                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 709                         if (!control_needs_exit && !dev->flags)
 710                                 continue;
 711                         /*
 712                          * Little race: we can create thread but not set the flag.
 713                          * Get a chance for external process to set flag up.
 714                          */
 715                         if (!dev->initialized) {
 716                                 have_to_wait = 1;
 717                                 continue;
 718                         }
 719
 720                         if (control_needs_exit) {
 721                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 722
 723                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 724                                 if (err)
 725                                         dev_err(&dev->dev,
 726                                                  "Failed to send signal to w1 kernel thread %d.\n",
 727                                                  dev->kpid);
 728                         }
 729
 730                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 731                                 wait_for_completion(&dev->dev_exited);
 732                                 spin_lock_bh(&w1_mlock);
 733                                 list_del(&dev->w1_master_entry);
 734                                 spin_unlock_bh(&w1_mlock);
 735
 736                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 737                                         list_del(&sl->w1_slave_entry);
 738
 739                                         w1_slave_detach(sl);
 740                                         kfree(sl);
 741                                 }
 742                                 w1_destroy_master_attributes(dev);
 743                                 atomic_dec(&dev->refcnt);
 744                                 continue;
 745                         }
 746
 747                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 748                                 dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 749                                 down(&dev->mutex);
 750                                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 751                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 752                                                 struct w1_reg_num rn;
 753                                                 list_del(&sl->w1_slave_entry);
 754                                                 w1_slave_detach(sl);
 755
 756                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 757
 758                                                 kfree(sl);
 759
 760                                                 w1_attach_slave_device(dev, &rn);
 761                                         }
 762                                 }
 763                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 764                                 up(&dev->mutex);
 765                         }
 766                 }
 767         }
 768
 769         complete_and_exit(&w1_control_complete, 0);
 770 }
 771
 772 int w1_process(void *data)
 773 {
 774         struct w1_master *dev = (struct w1_master *) data;
 775         struct w1_slave *sl, *sln;
 776
 777         daemonize("%s", dev->name);
 778         allow_signal(SIGTERM);
 779
 780         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 781                 try_to_freeze();
 782                 msleep_interruptible(w1_timeout * 1000);
 783
 784                 if (signal_pending(current))
 785                         flush_signals(current);
 786
 787                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 788                         break;
 789
 790                 if (!dev->initialized)
 791                         continue;
 792
 793                 if (dev->search_count == 0)
 794                         continue;
 795
 796                 if (down_interruptible(&dev->mutex))
 797                         continue;
 798
 799                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 800                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 801
 802                 w1_search_devices(dev, w1_slave_found);
 803
 804                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 805                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 806                                 list_del (&sl->w1_slave_entry);
 807
 808                                 w1_slave_detach (sl);
 809                                 kfree (sl);
 810
 811                                 dev->slave_count--;
 812                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 813                                 sl->ttl = dev->slave_ttl;
 814                 }
 815
 816                 if (dev->search_count > 0)
 817                         dev->search_count--;
 818
 819                 up(&dev->mutex);
 820         }
 821
 822         atomic_dec(&dev->refcnt);
 823         complete_and_exit(&dev->dev_exited, 0);
 824
 825         return 0;
 826 }
 827
 828 static int w1_init(void)
 829 {
 830         int retval;
 831
 832         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 833
 834         retval = bus_register(&w1_bus_type);
 835         if (retval) {
 836                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 837                 goto err_out_exit_init;
 838         }
 839
 840         retval = driver_register(&w1_master_driver);
 841         if (retval) {
 842                 printk(KERN_ERR
 843                         "Failed to register master driver. err=%d.\n",
 844                         retval);
 845                 goto err_out_bus_unregister;
 846         }
 847
 848         retval = driver_register(&w1_slave_driver);
 849         if (retval) {
 850                 printk(KERN_ERR
 851                         "Failed to register master driver. err=%d.\n",
 852                         retval);
 853                 goto err_out_master_unregister;
 854         }
 855
 856         control_thread = kernel_thread(&w1_control, NULL, 0);
 857         if (control_thread < 0) {
 858                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 859                         control_thread);
 860                 retval = control_thread;
 861                 goto err_out_slave_unregister;
 862         }
 863
 864         return 0;
 865
 866 err_out_slave_unregister:
 867         driver_unregister(&w1_slave_driver);
 868
 869 err_out_master_unregister:
 870         driver_unregister(&w1_master_driver);
 871
 872 err_out_bus_unregister:
 873         bus_unregister(&w1_bus_type);
 874
 875 err_out_exit_init:
 876         return retval;
 877 }
 878
 879 static void w1_fini(void)
 880 {
 881         struct w1_master *dev;
 882
 883         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 884                 __w1_remove_master_device(dev);
 885
 886         control_needs_exit = 1;
 887         wait_for_completion(&w1_control_complete);
 888
 889         driver_unregister(&w1_slave_driver);
 890         driver_unregister(&w1_master_driver);
 891         bus_unregister(&w1_bus_type);
 892 }
 893
 894 module_init(w1_init);
 895 module_exit(w1_fini);