drivers/w1/w1.c

   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
   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 <linux/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 <zbr@ioremap.net>");
  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_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
  60
  61 static int w1_master_match(struct device *dev, struct device_driver *drv)
  62 {
  63         return 1;
  64 }
  65
  66 static int w1_master_probe(struct device *dev)
  67 {
  68         return -ENODEV;
  69 }
  70
  71 static void w1_master_release(struct device *dev)
  72 {
  73         struct w1_master *md = dev_to_w1_master(dev);
  74
  75         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  76         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  77         kfree(md);
  78 }
  79
  80 static void w1_slave_release(struct device *dev)
  81 {
  82         struct w1_slave *sl = dev_to_w1_slave(dev);
  83
  84         dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
  85
  86         while (atomic_read(&sl->refcnt)) {
  87                 dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
  88                                 sl->name, atomic_read(&sl->refcnt));
  89                 if (msleep_interruptible(1000))
  90                         flush_signals(current);
  91         }
  92
  93         w1_family_put(sl->family);
  94         sl->master->slave_count--;
  95
  96         complete(&sl->released);
  97 }
  98
  99 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 100 {
 101         struct w1_slave *sl = dev_to_w1_slave(dev);
 102
 103         return sprintf(buf, "%s\n", sl->name);
 104 }
 105
 106 static ssize_t w1_slave_read_id(struct device *dev,
 107         struct device_attribute *attr, char *buf)
 108 {
 109         struct w1_slave *sl = dev_to_w1_slave(dev);
 110         ssize_t count = sizeof(sl->reg_num);
 111
 112         memcpy(buf, (u8 *)&sl->reg_num, count);
 113         return count;
 114 }
 115
 116 static struct device_attribute w1_slave_attr_name =
 117         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 118 static struct device_attribute w1_slave_attr_id =
 119         __ATTR(id, S_IRUGO, w1_slave_read_id, NULL);
 120
 121 /* Default family */
 122
 123 static ssize_t w1_default_write(struct file *filp, struct kobject *kobj,
 124                                 struct bin_attribute *bin_attr,
 125                                 char *buf, loff_t off, size_t count)
 126 {
 127         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 128
 129         mutex_lock(&sl->master->mutex);
 130         if (w1_reset_select_slave(sl)) {
 131                 count = 0;
 132                 goto out_up;
 133         }
 134
 135         w1_write_block(sl->master, buf, count);
 136
 137 out_up:
 138         mutex_unlock(&sl->master->mutex);
 139         return count;
 140 }
 141
 142 static ssize_t w1_default_read(struct file *filp, struct kobject *kobj,
 143                                struct bin_attribute *bin_attr,
 144                                char *buf, loff_t off, size_t count)
 145 {
 146         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 147
 148         mutex_lock(&sl->master->mutex);
 149         w1_read_block(sl->master, buf, count);
 150         mutex_unlock(&sl->master->mutex);
 151         return count;
 152 }
 153
 154 static struct bin_attribute w1_default_attr = {
 155       .attr = {
 156               .name = "rw",
 157               .mode = S_IRUGO | S_IWUSR,
 158       },
 159       .size = PAGE_SIZE,
 160       .read = w1_default_read,
 161       .write = w1_default_write,
 162 };
 163
 164 static int w1_default_add_slave(struct w1_slave *sl)
 165 {
 166         return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 167 }
 168
 169 static void w1_default_remove_slave(struct w1_slave *sl)
 170 {
 171         sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 172 }
 173
 174 static struct w1_family_ops w1_default_fops = {
 175         .add_slave      = w1_default_add_slave,
 176         .remove_slave   = w1_default_remove_slave,
 177 };
 178
 179 static struct w1_family w1_default_family = {
 180         .fops = &w1_default_fops,
 181 };
 182
 183 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 184
 185 static struct bus_type w1_bus_type = {
 186         .name = "w1",
 187         .match = w1_master_match,
 188         .uevent = w1_uevent,
 189 };
 190
 191 struct device_driver w1_master_driver = {
 192         .name = "w1_master_driver",
 193         .bus = &w1_bus_type,
 194         .probe = w1_master_probe,
 195 };
 196
 197 struct device w1_master_device = {
 198         .parent = NULL,
 199         .bus = &w1_bus_type,
 200         .init_name = "w1 bus master",
 201         .driver = &w1_master_driver,
 202         .release = &w1_master_release
 203 };
 204
 205 static struct device_driver w1_slave_driver = {
 206         .name = "w1_slave_driver",
 207         .bus = &w1_bus_type,
 208 };
 209
 210 #if 0
 211 struct device w1_slave_device = {
 212         .parent = NULL,
 213         .bus = &w1_bus_type,
 214         .init_name = "w1 bus slave",
 215         .driver = &w1_slave_driver,
 216         .release = &w1_slave_release
 217 };
 218 #endif  /*  0  */
 219
 220 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 221 {
 222         struct w1_master *md = dev_to_w1_master(dev);
 223         ssize_t count;
 224
 225         mutex_lock(&md->mutex);
 226         count = sprintf(buf, "%s\n", md->name);
 227         mutex_unlock(&md->mutex);
 228
 229         return count;
 230 }
 231
 232 static ssize_t w1_master_attribute_store_search(struct device * dev,
 233                                                 struct device_attribute *attr,
 234                                                 const char * buf, size_t count)
 235 {
 236         long tmp;
 237         struct w1_master *md = dev_to_w1_master(dev);
 238
 239         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
 240                 return -EINVAL;
 241
 242         mutex_lock(&md->mutex);
 243         md->search_count = tmp;
 244         mutex_unlock(&md->mutex);
 245         wake_up_process(md->thread);
 246
 247         return count;
 248 }
 249
 250 static ssize_t w1_master_attribute_show_search(struct device *dev,
 251                                                struct device_attribute *attr,
 252                                                char *buf)
 253 {
 254         struct w1_master *md = dev_to_w1_master(dev);
 255         ssize_t count;
 256
 257         mutex_lock(&md->mutex);
 258         count = sprintf(buf, "%d\n", md->search_count);
 259         mutex_unlock(&md->mutex);
 260
 261         return count;
 262 }
 263
 264 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
 265                                                 struct device_attribute *attr,
 266                                                 const char *buf, size_t count)
 267 {
 268         long tmp;
 269         struct w1_master *md = dev_to_w1_master(dev);
 270
 271         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
 272                 return -EINVAL;
 273
 274         mutex_lock(&md->mutex);
 275         md->enable_pullup = tmp;
 276         mutex_unlock(&md->mutex);
 277         wake_up_process(md->thread);
 278
 279         return count;
 280 }
 281
 282 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
 283                                                struct device_attribute *attr,
 284                                                char *buf)
 285 {
 286         struct w1_master *md = dev_to_w1_master(dev);
 287         ssize_t count;
 288
 289         mutex_lock(&md->mutex);
 290         count = sprintf(buf, "%d\n", md->enable_pullup);
 291         mutex_unlock(&md->mutex);
 292
 293         return count;
 294 }
 295
 296 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 297 {
 298         struct w1_master *md = dev_to_w1_master(dev);
 299         ssize_t count;
 300
 301         mutex_lock(&md->mutex);
 302         count = sprintf(buf, "0x%p\n", md->bus_master);
 303         mutex_unlock(&md->mutex);
 304         return count;
 305 }
 306
 307 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 308 {
 309         ssize_t count;
 310         count = sprintf(buf, "%d\n", w1_timeout);
 311         return count;
 312 }
 313
 314 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 315 {
 316         struct w1_master *md = dev_to_w1_master(dev);
 317         ssize_t count;
 318
 319         mutex_lock(&md->mutex);
 320         count = sprintf(buf, "%d\n", md->max_slave_count);
 321         mutex_unlock(&md->mutex);
 322         return count;
 323 }
 324
 325 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 326 {
 327         struct w1_master *md = dev_to_w1_master(dev);
 328         ssize_t count;
 329
 330         mutex_lock(&md->mutex);
 331         count = sprintf(buf, "%lu\n", md->attempts);
 332         mutex_unlock(&md->mutex);
 333         return count;
 334 }
 335
 336 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 337 {
 338         struct w1_master *md = dev_to_w1_master(dev);
 339         ssize_t count;
 340
 341         mutex_lock(&md->mutex);
 342         count = sprintf(buf, "%d\n", md->slave_count);
 343         mutex_unlock(&md->mutex);
 344         return count;
 345 }
 346
 347 static ssize_t w1_master_attribute_show_slaves(struct device *dev,
 348         struct device_attribute *attr, char *buf)
 349 {
 350         struct w1_master *md = dev_to_w1_master(dev);
 351         int c = PAGE_SIZE;
 352
 353         mutex_lock(&md->mutex);
 354
 355         if (md->slave_count == 0)
 356                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 357         else {
 358                 struct list_head *ent, *n;
 359                 struct w1_slave *sl;
 360
 361                 list_for_each_safe(ent, n, &md->slist) {
 362                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 363
 364                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 365                 }
 366         }
 367
 368         mutex_unlock(&md->mutex);
 369
 370         return PAGE_SIZE - c;
 371 }
 372
 373 static ssize_t w1_master_attribute_show_add(struct device *dev,
 374         struct device_attribute *attr, char *buf)
 375 {
 376         int c = PAGE_SIZE;
 377         c -= snprintf(buf+PAGE_SIZE - c, c,
 378                 "write device id xx-xxxxxxxxxxxx to add slave\n");
 379         return PAGE_SIZE - c;
 380 }
 381
 382 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
 383         struct w1_reg_num *rn)
 384 {
 385         unsigned int family;
 386         unsigned long long id;
 387         int i;
 388         u64 rn64_le;
 389
 390         /* The CRC value isn't read from the user because the sysfs directory
 391          * doesn't include it and most messages from the bus search don't
 392          * print it either.  It would be unreasonable for the user to then
 393          * provide it.
 394          */
 395         const char *error_msg = "bad slave string format, expecting "
 396                 "ff-dddddddddddd\n";
 397
 398         if (buf[2] != '-') {
 399                 dev_err(dev, "%s", error_msg);
 400                 return -EINVAL;
 401         }
 402         i = sscanf(buf, "%02x-%012llx", &family, &id);
 403         if (i != 2) {
 404                 dev_err(dev, "%s", error_msg);
 405                 return -EINVAL;
 406         }
 407         rn->family = family;
 408         rn->id = id;
 409
 410         rn64_le = cpu_to_le64(*(u64 *)rn);
 411         rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
 412
 413 #if 0
 414         dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
 415                   rn->family, (unsigned long long)rn->id, rn->crc);
 416 #endif
 417
 418         return 0;
 419 }
 420
 421 /* Searches the slaves in the w1_master and returns a pointer or NULL.
 422  * Note: must hold the mutex
 423  */
 424 static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
 425         struct w1_reg_num *rn)
 426 {
 427         struct w1_slave *sl;
 428         list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 429                 if (sl->reg_num.family == rn->family &&
 430                                 sl->reg_num.id == rn->id &&
 431                                 sl->reg_num.crc == rn->crc) {
 432                         return sl;
 433                 }
 434         }
 435         return NULL;
 436 }
 437
 438 static ssize_t w1_master_attribute_store_add(struct device *dev,
 439                                                 struct device_attribute *attr,
 440                                                 const char *buf, size_t count)
 441 {
 442         struct w1_master *md = dev_to_w1_master(dev);
 443         struct w1_reg_num rn;
 444         struct w1_slave *sl;
 445         ssize_t result = count;
 446
 447         if (w1_atoreg_num(dev, buf, count, &rn))
 448                 return -EINVAL;
 449
 450         mutex_lock(&md->mutex);
 451         sl = w1_slave_search_device(md, &rn);
 452         /* It would be nice to do a targeted search one the one-wire bus
 453          * for the new device to see if it is out there or not.  But the
 454          * current search doesn't support that.
 455          */
 456         if (sl) {
 457                 dev_info(dev, "Device %s already exists\n", sl->name);
 458                 result = -EINVAL;
 459         } else {
 460                 w1_attach_slave_device(md, &rn);
 461         }
 462         mutex_unlock(&md->mutex);
 463
 464         return result;
 465 }
 466
 467 static ssize_t w1_master_attribute_show_remove(struct device *dev,
 468         struct device_attribute *attr, char *buf)
 469 {
 470         int c = PAGE_SIZE;
 471         c -= snprintf(buf+PAGE_SIZE - c, c,
 472                 "write device id xx-xxxxxxxxxxxx to remove slave\n");
 473         return PAGE_SIZE - c;
 474 }
 475
 476 static ssize_t w1_master_attribute_store_remove(struct device *dev,
 477                                                 struct device_attribute *attr,
 478                                                 const char *buf, size_t count)
 479 {
 480         struct w1_master *md = dev_to_w1_master(dev);
 481         struct w1_reg_num rn;
 482         struct w1_slave *sl;
 483         ssize_t result = count;
 484
 485         if (w1_atoreg_num(dev, buf, count, &rn))
 486                 return -EINVAL;
 487
 488         mutex_lock(&md->mutex);
 489         sl = w1_slave_search_device(md, &rn);
 490         if (sl) {
 491                 w1_slave_detach(sl);
 492         } else {
 493                 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
 494                         (unsigned long long)rn.id);
 495                 result = -EINVAL;
 496         }
 497         mutex_unlock(&md->mutex);
 498
 499         return result;
 500 }
 501
 502 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 503         struct device_attribute w1_master_attribute_##_name =   \
 504                 __ATTR(w1_master_##_name, _mode,                \
 505                        w1_master_attribute_show_##_name, NULL)
 506
 507 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 508         struct device_attribute w1_master_attribute_##_name =   \
 509                 __ATTR(w1_master_##_name, _mode,                \
 510                        w1_master_attribute_show_##_name,        \
 511                        w1_master_attribute_store_##_name)
 512
 513 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 514 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 515 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 516 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 517 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 518 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 519 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 520 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
 521 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
 522 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
 523 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
 524
 525 static struct attribute *w1_master_default_attrs[] = {
 526         &w1_master_attribute_name.attr,
 527         &w1_master_attribute_slaves.attr,
 528         &w1_master_attribute_slave_count.attr,
 529         &w1_master_attribute_max_slave_count.attr,
 530         &w1_master_attribute_attempts.attr,
 531         &w1_master_attribute_timeout.attr,
 532         &w1_master_attribute_pointer.attr,
 533         &w1_master_attribute_search.attr,
 534         &w1_master_attribute_pullup.attr,
 535         &w1_master_attribute_add.attr,
 536         &w1_master_attribute_remove.attr,
 537         NULL
 538 };
 539
 540 static struct attribute_group w1_master_defattr_group = {
 541         .attrs = w1_master_default_attrs,
 542 };
 543
 544 int w1_create_master_attributes(struct w1_master *master)
 545 {
 546         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 547 }
 548
 549 void w1_destroy_master_attributes(struct w1_master *master)
 550 {
 551         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 552 }
 553
 554 #ifdef CONFIG_HOTPLUG
 555 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 556 {
 557         struct w1_master *md = NULL;
 558         struct w1_slave *sl = NULL;
 559         char *event_owner, *name;
 560         int err;
 561
 562         if (dev->driver == &w1_master_driver) {
 563                 md = container_of(dev, struct w1_master, dev);
 564                 event_owner = "master";
 565                 name = md->name;
 566         } else if (dev->driver == &w1_slave_driver) {
 567                 sl = container_of(dev, struct w1_slave, dev);
 568                 event_owner = "slave";
 569                 name = sl->name;
 570         } else {
 571                 dev_dbg(dev, "Unknown event.\n");
 572                 return -EINVAL;
 573         }
 574
 575         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 576                         event_owner, name, dev_name(dev));
 577
 578         if (dev->driver != &w1_slave_driver || !sl)
 579                 return 0;
 580
 581         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 582         if (err)
 583                 return err;
 584
 585         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 586                              (unsigned long long)sl->reg_num.id);
 587         if (err)
 588                 return err;
 589
 590         return 0;
 591 };
 592 #else
 593 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 594 {
 595         return 0;
 596 }
 597 #endif
 598
 599 static int __w1_attach_slave_device(struct w1_slave *sl)
 600 {
 601         int err;
 602
 603         sl->dev.parent = &sl->master->dev;
 604         sl->dev.driver = &w1_slave_driver;
 605         sl->dev.bus = &w1_bus_type;
 606         sl->dev.release = &w1_slave_release;
 607
 608         dev_set_name(&sl->dev, "%02x-%012llx",
 609                  (unsigned int) sl->reg_num.family,
 610                  (unsigned long long) sl->reg_num.id);
 611         snprintf(&sl->name[0], sizeof(sl->name),
 612                  "%02x-%012llx",
 613                  (unsigned int) sl->reg_num.family,
 614                  (unsigned long long) sl->reg_num.id);
 615
 616         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 617                 dev_name(&sl->dev), sl);
 618
 619         err = device_register(&sl->dev);
 620         if (err < 0) {
 621                 dev_err(&sl->dev,
 622                         "Device registration [%s] failed. err=%d\n",
 623                         dev_name(&sl->dev), err);
 624                 return err;
 625         }
 626
 627         /* Create "name" entry */
 628         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 629         if (err < 0) {
 630                 dev_err(&sl->dev,
 631                         "sysfs file creation for [%s] failed. err=%d\n",
 632                         dev_name(&sl->dev), err);
 633                 goto out_unreg;
 634         }
 635
 636         /* Create "id" entry */
 637         err = device_create_file(&sl->dev, &w1_slave_attr_id);
 638         if (err < 0) {
 639                 dev_err(&sl->dev,
 640                         "sysfs file creation for [%s] failed. err=%d\n",
 641                         dev_name(&sl->dev), err);
 642                 goto out_rem1;
 643         }
 644
 645         /* if the family driver needs to initialize something... */
 646         if (sl->family->fops && sl->family->fops->add_slave &&
 647             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 648                 dev_err(&sl->dev,
 649                         "sysfs file creation for [%s] failed. err=%d\n",
 650                         dev_name(&sl->dev), err);
 651                 goto out_rem2;
 652         }
 653
 654         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 655
 656         return 0;
 657
 658 out_rem2:
 659         device_remove_file(&sl->dev, &w1_slave_attr_id);
 660 out_rem1:
 661         device_remove_file(&sl->dev, &w1_slave_attr_name);
 662 out_unreg:
 663         device_unregister(&sl->dev);
 664         return err;
 665 }
 666
 667 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 668 {
 669         struct w1_slave *sl;
 670         struct w1_family *f;
 671         int err;
 672         struct w1_netlink_msg msg;
 673
 674         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 675         if (!sl) {
 676                 dev_err(&dev->dev,
 677                          "%s: failed to allocate new slave device.\n",
 678                          __func__);
 679                 return -ENOMEM;
 680         }
 681
 682
 683         sl->owner = THIS_MODULE;
 684         sl->master = dev;
 685         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 686
 687         memset(&msg, 0, sizeof(msg));
 688         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 689         atomic_set(&sl->refcnt, 0);
 690         init_completion(&sl->released);
 691
 692         spin_lock(&w1_flock);
 693         f = w1_family_registered(rn->family);
 694         if (!f) {
 695                 f= &w1_default_family;
 696                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 697                           rn->family, rn->family,
 698                           (unsigned long long)rn->id, rn->crc);
 699         }
 700         __w1_family_get(f);
 701         spin_unlock(&w1_flock);
 702
 703         sl->family = f;
 704
 705
 706         err = __w1_attach_slave_device(sl);
 707         if (err < 0) {
 708                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 709                          sl->name);
 710                 w1_family_put(sl->family);
 711                 kfree(sl);
 712                 return err;
 713         }
 714
 715         sl->ttl = dev->slave_ttl;
 716         dev->slave_count++;
 717
 718         memcpy(msg.id.id, rn, sizeof(msg.id));
 719         msg.type = W1_SLAVE_ADD;
 720         w1_netlink_send(dev, &msg);
 721
 722         return 0;
 723 }
 724
 725 void w1_slave_detach(struct w1_slave *sl)
 726 {
 727         struct w1_netlink_msg msg;
 728
 729         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 730
 731         list_del(&sl->w1_slave_entry);
 732
 733         if (sl->family->fops && sl->family->fops->remove_slave)
 734                 sl->family->fops->remove_slave(sl);
 735
 736         memset(&msg, 0, sizeof(msg));
 737         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 738         msg.type = W1_SLAVE_REMOVE;
 739         w1_netlink_send(sl->master, &msg);
 740
 741         device_remove_file(&sl->dev, &w1_slave_attr_id);
 742         device_remove_file(&sl->dev, &w1_slave_attr_name);
 743         device_unregister(&sl->dev);
 744
 745         wait_for_completion(&sl->released);
 746         kfree(sl);
 747 }
 748
 749 struct w1_master *w1_search_master_id(u32 id)
 750 {
 751         struct w1_master *dev;
 752         int found = 0;
 753
 754         mutex_lock(&w1_mlock);
 755         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 756                 if (dev->id == id) {
 757                         found = 1;
 758                         atomic_inc(&dev->refcnt);
 759                         break;
 760                 }
 761         }
 762         mutex_unlock(&w1_mlock);
 763
 764         return (found)?dev:NULL;
 765 }
 766
 767 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 768 {
 769         struct w1_master *dev;
 770         struct w1_slave *sl = NULL;
 771         int found = 0;
 772
 773         mutex_lock(&w1_mlock);
 774         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 775                 mutex_lock(&dev->mutex);
 776                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 777                         if (sl->reg_num.family == id->family &&
 778                                         sl->reg_num.id == id->id &&
 779                                         sl->reg_num.crc == id->crc) {
 780                                 found = 1;
 781                                 atomic_inc(&dev->refcnt);
 782                                 atomic_inc(&sl->refcnt);
 783                                 break;
 784                         }
 785                 }
 786                 mutex_unlock(&dev->mutex);
 787
 788                 if (found)
 789                         break;
 790         }
 791         mutex_unlock(&w1_mlock);
 792
 793         return (found)?sl:NULL;
 794 }
 795
 796 void w1_reconnect_slaves(struct w1_family *f, int attach)
 797 {
 798         struct w1_slave *sl, *sln;
 799         struct w1_master *dev;
 800
 801         mutex_lock(&w1_mlock);
 802         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 803                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 804                         "for family %02x.\n", dev->name, f->fid);
 805                 mutex_lock(&dev->mutex);
 806                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 807                         /* If it is a new family, slaves with the default
 808                          * family driver and are that family will be
 809                          * connected.  If the family is going away, devices
 810                          * matching that family are reconneced.
 811                          */
 812                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 813                                 && sl->reg_num.family == f->fid) ||
 814                                 (!attach && sl->family->fid == f->fid)) {
 815                                 struct w1_reg_num rn;
 816
 817                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 818                                 w1_slave_detach(sl);
 819
 820                                 w1_attach_slave_device(dev, &rn);
 821                         }
 822                 }
 823                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 824                         "has been finished.\n", dev->name);
 825                 mutex_unlock(&dev->mutex);
 826         }
 827         mutex_unlock(&w1_mlock);
 828 }
 829
 830 void w1_slave_found(struct w1_master *dev, u64 rn)
 831 {
 832         struct w1_slave *sl;
 833         struct w1_reg_num *tmp;
 834         u64 rn_le = cpu_to_le64(rn);
 835
 836         atomic_inc(&dev->refcnt);
 837
 838         tmp = (struct w1_reg_num *) &rn;
 839
 840         sl = w1_slave_search_device(dev, tmp);
 841         if (sl) {
 842                 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 843         } else {
 844                 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
 845                         w1_attach_slave_device(dev, tmp);
 846         }
 847
 848         atomic_dec(&dev->refcnt);
 849 }
 850
 851 /**
 852  * Performs a ROM Search & registers any devices found.
 853  * The 1-wire search is a simple binary tree search.
 854  * For each bit of the address, we read two bits and write one bit.
 855  * The bit written will put to sleep all devies that don't match that bit.
 856  * When the two reads differ, the direction choice is obvious.
 857  * When both bits are 0, we must choose a path to take.
 858  * When we can scan all 64 bits without having to choose a path, we are done.
 859  *
 860  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 861  *
 862  * @dev        The master device to search
 863  * @cb         Function to call when a device is found
 864  */
 865 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 866 {
 867         u64 last_rn, rn, tmp64;
 868         int i, slave_count = 0;
 869         int last_zero, last_device;
 870         int search_bit, desc_bit;
 871         u8  triplet_ret = 0;
 872
 873         search_bit = 0;
 874         rn = last_rn = 0;
 875         last_device = 0;
 876         last_zero = -1;
 877
 878         desc_bit = 64;
 879
 880         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 881                 last_rn = rn;
 882                 rn = 0;
 883
 884                 /*
 885                  * Reset bus and all 1-wire device state machines
 886                  * so they can respond to our requests.
 887                  *
 888                  * Return 0 - device(s) present, 1 - no devices present.
 889                  */
 890                 if (w1_reset_bus(dev)) {
 891                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 892                         break;
 893                 }
 894
 895                 /* Start the search */
 896                 w1_write_8(dev, search_type);
 897                 for (i = 0; i < 64; ++i) {
 898                         /* Determine the direction/search bit */
 899                         if (i == desc_bit)
 900                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 901                         else if (i > desc_bit)
 902                                 search_bit = 0;   /* take the 0 path on the next branch */
 903                         else
 904                                 search_bit = ((last_rn >> i) & 0x1);
 905
 906                         /** Read two bits and write one bit */
 907                         triplet_ret = w1_triplet(dev, search_bit);
 908
 909                         /* quit if no device responded */
 910                         if ( (triplet_ret & 0x03) == 0x03 )
 911                                 break;
 912
 913                         /* If both directions were valid, and we took the 0 path... */
 914                         if (triplet_ret == 0)
 915                                 last_zero = i;
 916
 917                         /* extract the direction taken & update the device number */
 918                         tmp64 = (triplet_ret >> 2);
 919                         rn |= (tmp64 << i);
 920
 921                         if (kthread_should_stop()) {
 922                                 dev_dbg(&dev->dev, "Abort w1_search\n");
 923                                 return;
 924                         }
 925                 }
 926
 927                 if ( (triplet_ret & 0x03) != 0x03 ) {
 928                         if ( (desc_bit == last_zero) || (last_zero < 0))
 929                                 last_device = 1;
 930                         desc_bit = last_zero;
 931                         cb(dev, rn);
 932                 }
 933         }
 934 }
 935
 936 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
 937         w1_slave_found_callback cb)
 938 {
 939         struct w1_slave *sl, *sln;
 940
 941         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 942                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 943
 944         w1_search_devices(dev, search_type, cb);
 945
 946         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 947                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
 948                         w1_slave_detach(sl);
 949                 else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 950                         sl->ttl = dev->slave_ttl;
 951         }
 952
 953         if (dev->search_count > 0)
 954                 dev->search_count--;
 955 }
 956
 957 static void w1_search_process(struct w1_master *dev, u8 search_type)
 958 {
 959         w1_search_process_cb(dev, search_type, w1_slave_found);
 960 }
 961
 962 int w1_process(void *data)
 963 {
 964         struct w1_master *dev = (struct w1_master *) data;
 965         /* As long as w1_timeout is only set by a module parameter the sleep
 966          * time can be calculated in jiffies once.
 967          */
 968         const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
 969
 970         while (!kthread_should_stop()) {
 971                 if (dev->search_count) {
 972                         mutex_lock(&dev->mutex);
 973                         w1_search_process(dev, W1_SEARCH);
 974                         mutex_unlock(&dev->mutex);
 975                 }
 976
 977                 try_to_freeze();
 978                 __set_current_state(TASK_INTERRUPTIBLE);
 979
 980                 if (kthread_should_stop())
 981                         break;
 982
 983                 /* Only sleep when the search is active. */
 984                 if (dev->search_count)
 985                         schedule_timeout(jtime);
 986                 else
 987                         schedule();
 988         }
 989
 990         atomic_dec(&dev->refcnt);
 991
 992         return 0;
 993 }
 994
 995 static int __init w1_init(void)
 996 {
 997         int retval;
 998
 999         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
1000
1001         w1_init_netlink();
1002
1003         retval = bus_register(&w1_bus_type);
1004         if (retval) {
1005                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
1006                 goto err_out_exit_init;
1007         }
1008
1009         retval = driver_register(&w1_master_driver);
1010         if (retval) {
1011                 printk(KERN_ERR
1012                         "Failed to register master driver. err=%d.\n",
1013                         retval);
1014                 goto err_out_bus_unregister;
1015         }
1016
1017         retval = driver_register(&w1_slave_driver);
1018         if (retval) {
1019                 printk(KERN_ERR
1020                         "Failed to register master driver. err=%d.\n",
1021                         retval);
1022                 goto err_out_master_unregister;
1023         }
1024
1025         return 0;
1026
1027 #if 0
1028 /* For undoing the slave register if there was a step after it. */
1029 err_out_slave_unregister:
1030         driver_unregister(&w1_slave_driver);
1031 #endif
1032
1033 err_out_master_unregister:
1034         driver_unregister(&w1_master_driver);
1035
1036 err_out_bus_unregister:
1037         bus_unregister(&w1_bus_type);
1038
1039 err_out_exit_init:
1040         return retval;
1041 }
1042
1043 static void __exit w1_fini(void)
1044 {
1045         struct w1_master *dev;
1046
1047         /* Set netlink removal messages and some cleanup */
1048         list_for_each_entry(dev, &w1_masters, w1_master_entry)
1049                 __w1_remove_master_device(dev);
1050
1051         w1_fini_netlink();
1052
1053         driver_unregister(&w1_slave_driver);
1054         driver_unregister(&w1_master_driver);
1055         bus_unregister(&w1_bus_type);
1056 }
1057
1058 module_init(w1_init);
1059 module_exit(w1_fini);