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 name_show(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 static DEVICE_ATTR_RO(name);
 106
 107 static ssize_t id_show(struct device *dev,
 108         struct device_attribute *attr, char *buf)
 109 {
 110         struct w1_slave *sl = dev_to_w1_slave(dev);
 111         ssize_t count = sizeof(sl->reg_num);
 112
 113         memcpy(buf, (u8 *)&sl->reg_num, count);
 114         return count;
 115 }
 116 static DEVICE_ATTR_RO(id);
 117
 118 static struct attribute *w1_slave_attrs[] = {
 119         &dev_attr_name.attr,
 120         &dev_attr_id.attr,
 121         NULL,
 122 };
 123 ATTRIBUTE_GROUPS(w1_slave);
 124
 125 /* Default family */
 126
 127 static ssize_t rw_write(struct file *filp, struct kobject *kobj,
 128                         struct bin_attribute *bin_attr, char *buf, loff_t off,
 129                         size_t count)
 130 {
 131         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 132
 133         mutex_lock(&sl->master->mutex);
 134         if (w1_reset_select_slave(sl)) {
 135                 count = 0;
 136                 goto out_up;
 137         }
 138
 139         w1_write_block(sl->master, buf, count);
 140
 141 out_up:
 142         mutex_unlock(&sl->master->mutex);
 143         return count;
 144 }
 145
 146 static ssize_t rw_read(struct file *filp, struct kobject *kobj,
 147                        struct bin_attribute *bin_attr, char *buf, loff_t off,
 148                        size_t count)
 149 {
 150         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 151
 152         mutex_lock(&sl->master->mutex);
 153         w1_read_block(sl->master, buf, count);
 154         mutex_unlock(&sl->master->mutex);
 155         return count;
 156 }
 157
 158 static BIN_ATTR_RW(rw, PAGE_SIZE);
 159
 160 static struct bin_attribute *w1_slave_bin_attrs[] = {
 161         &bin_attr_rw,
 162         NULL,
 163 };
 164
 165 static const struct attribute_group w1_slave_default_group = {
 166         .bin_attrs = w1_slave_bin_attrs,
 167 };
 168
 169 static const struct attribute_group *w1_slave_default_groups[] = {
 170         &w1_slave_default_group,
 171         NULL,
 172 };
 173
 174 static struct w1_family_ops w1_default_fops = {
 175         .groups         = w1_slave_default_groups,
 176 };
 177
 178 static struct w1_family w1_default_family = {
 179         .fops = &w1_default_fops,
 180 };
 181
 182 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 183
 184 static struct bus_type w1_bus_type = {
 185         .name = "w1",
 186         .match = w1_master_match,
 187         .uevent = w1_uevent,
 188 };
 189
 190 struct device_driver w1_master_driver = {
 191         .name = "w1_master_driver",
 192         .bus = &w1_bus_type,
 193         .probe = w1_master_probe,
 194 };
 195
 196 struct device w1_master_device = {
 197         .parent = NULL,
 198         .bus = &w1_bus_type,
 199         .init_name = "w1 bus master",
 200         .driver = &w1_master_driver,
 201         .release = &w1_master_release
 202 };
 203
 204 static struct device_driver w1_slave_driver = {
 205         .name = "w1_slave_driver",
 206         .bus = &w1_bus_type,
 207 };
 208
 209 #if 0
 210 struct device w1_slave_device = {
 211         .parent = NULL,
 212         .bus = &w1_bus_type,
 213         .init_name = "w1 bus slave",
 214         .driver = &w1_slave_driver,
 215         .release = &w1_slave_release
 216 };
 217 #endif  /*  0  */
 218
 219 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 220 {
 221         struct w1_master *md = dev_to_w1_master(dev);
 222         ssize_t count;
 223
 224         mutex_lock(&md->mutex);
 225         count = sprintf(buf, "%s\n", md->name);
 226         mutex_unlock(&md->mutex);
 227
 228         return count;
 229 }
 230
 231 static ssize_t w1_master_attribute_store_search(struct device * dev,
 232                                                 struct device_attribute *attr,
 233                                                 const char * buf, size_t count)
 234 {
 235         long tmp;
 236         struct w1_master *md = dev_to_w1_master(dev);
 237
 238         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
 239                 return -EINVAL;
 240
 241         mutex_lock(&md->mutex);
 242         md->search_count = tmp;
 243         mutex_unlock(&md->mutex);
 244         wake_up_process(md->thread);
 245
 246         return count;
 247 }
 248
 249 static ssize_t w1_master_attribute_show_search(struct device *dev,
 250                                                struct device_attribute *attr,
 251                                                char *buf)
 252 {
 253         struct w1_master *md = dev_to_w1_master(dev);
 254         ssize_t count;
 255
 256         mutex_lock(&md->mutex);
 257         count = sprintf(buf, "%d\n", md->search_count);
 258         mutex_unlock(&md->mutex);
 259
 260         return count;
 261 }
 262
 263 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
 264                                                 struct device_attribute *attr,
 265                                                 const char *buf, size_t count)
 266 {
 267         long tmp;
 268         struct w1_master *md = dev_to_w1_master(dev);
 269
 270         if (strict_strtol(buf, 0, &tmp) == -EINVAL)
 271                 return -EINVAL;
 272
 273         mutex_lock(&md->mutex);
 274         md->enable_pullup = tmp;
 275         mutex_unlock(&md->mutex);
 276         wake_up_process(md->thread);
 277
 278         return count;
 279 }
 280
 281 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
 282                                                struct device_attribute *attr,
 283                                                char *buf)
 284 {
 285         struct w1_master *md = dev_to_w1_master(dev);
 286         ssize_t count;
 287
 288         mutex_lock(&md->mutex);
 289         count = sprintf(buf, "%d\n", md->enable_pullup);
 290         mutex_unlock(&md->mutex);
 291
 292         return count;
 293 }
 294
 295 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 296 {
 297         struct w1_master *md = dev_to_w1_master(dev);
 298         ssize_t count;
 299
 300         mutex_lock(&md->mutex);
 301         count = sprintf(buf, "0x%p\n", md->bus_master);
 302         mutex_unlock(&md->mutex);
 303         return count;
 304 }
 305
 306 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 307 {
 308         ssize_t count;
 309         count = sprintf(buf, "%d\n", w1_timeout);
 310         return count;
 311 }
 312
 313 static ssize_t w1_master_attribute_show_max_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->max_slave_count);
 320         mutex_unlock(&md->mutex);
 321         return count;
 322 }
 323
 324 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 325 {
 326         struct w1_master *md = dev_to_w1_master(dev);
 327         ssize_t count;
 328
 329         mutex_lock(&md->mutex);
 330         count = sprintf(buf, "%lu\n", md->attempts);
 331         mutex_unlock(&md->mutex);
 332         return count;
 333 }
 334
 335 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 336 {
 337         struct w1_master *md = dev_to_w1_master(dev);
 338         ssize_t count;
 339
 340         mutex_lock(&md->mutex);
 341         count = sprintf(buf, "%d\n", md->slave_count);
 342         mutex_unlock(&md->mutex);
 343         return count;
 344 }
 345
 346 static ssize_t w1_master_attribute_show_slaves(struct device *dev,
 347         struct device_attribute *attr, char *buf)
 348 {
 349         struct w1_master *md = dev_to_w1_master(dev);
 350         int c = PAGE_SIZE;
 351
 352         mutex_lock(&md->mutex);
 353
 354         if (md->slave_count == 0)
 355                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 356         else {
 357                 struct list_head *ent, *n;
 358                 struct w1_slave *sl;
 359
 360                 list_for_each_safe(ent, n, &md->slist) {
 361                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 362
 363                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 364                 }
 365         }
 366
 367         mutex_unlock(&md->mutex);
 368
 369         return PAGE_SIZE - c;
 370 }
 371
 372 static ssize_t w1_master_attribute_show_add(struct device *dev,
 373         struct device_attribute *attr, char *buf)
 374 {
 375         int c = PAGE_SIZE;
 376         c -= snprintf(buf+PAGE_SIZE - c, c,
 377                 "write device id xx-xxxxxxxxxxxx to add slave\n");
 378         return PAGE_SIZE - c;
 379 }
 380
 381 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
 382         struct w1_reg_num *rn)
 383 {
 384         unsigned int family;
 385         unsigned long long id;
 386         int i;
 387         u64 rn64_le;
 388
 389         /* The CRC value isn't read from the user because the sysfs directory
 390          * doesn't include it and most messages from the bus search don't
 391          * print it either.  It would be unreasonable for the user to then
 392          * provide it.
 393          */
 394         const char *error_msg = "bad slave string format, expecting "
 395                 "ff-dddddddddddd\n";
 396
 397         if (buf[2] != '-') {
 398                 dev_err(dev, "%s", error_msg);
 399                 return -EINVAL;
 400         }
 401         i = sscanf(buf, "%02x-%012llx", &family, &id);
 402         if (i != 2) {
 403                 dev_err(dev, "%s", error_msg);
 404                 return -EINVAL;
 405         }
 406         rn->family = family;
 407         rn->id = id;
 408
 409         rn64_le = cpu_to_le64(*(u64 *)rn);
 410         rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
 411
 412 #if 0
 413         dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
 414                   rn->family, (unsigned long long)rn->id, rn->crc);
 415 #endif
 416
 417         return 0;
 418 }
 419
 420 /* Searches the slaves in the w1_master and returns a pointer or NULL.
 421  * Note: must hold the mutex
 422  */
 423 static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
 424         struct w1_reg_num *rn)
 425 {
 426         struct w1_slave *sl;
 427         list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 428                 if (sl->reg_num.family == rn->family &&
 429                                 sl->reg_num.id == rn->id &&
 430                                 sl->reg_num.crc == rn->crc) {
 431                         return sl;
 432                 }
 433         }
 434         return NULL;
 435 }
 436
 437 static ssize_t w1_master_attribute_store_add(struct device *dev,
 438                                                 struct device_attribute *attr,
 439                                                 const char *buf, size_t count)
 440 {
 441         struct w1_master *md = dev_to_w1_master(dev);
 442         struct w1_reg_num rn;
 443         struct w1_slave *sl;
 444         ssize_t result = count;
 445
 446         if (w1_atoreg_num(dev, buf, count, &rn))
 447                 return -EINVAL;
 448
 449         mutex_lock(&md->mutex);
 450         sl = w1_slave_search_device(md, &rn);
 451         /* It would be nice to do a targeted search one the one-wire bus
 452          * for the new device to see if it is out there or not.  But the
 453          * current search doesn't support that.
 454          */
 455         if (sl) {
 456                 dev_info(dev, "Device %s already exists\n", sl->name);
 457                 result = -EINVAL;
 458         } else {
 459                 w1_attach_slave_device(md, &rn);
 460         }
 461         mutex_unlock(&md->mutex);
 462
 463         return result;
 464 }
 465
 466 static ssize_t w1_master_attribute_show_remove(struct device *dev,
 467         struct device_attribute *attr, char *buf)
 468 {
 469         int c = PAGE_SIZE;
 470         c -= snprintf(buf+PAGE_SIZE - c, c,
 471                 "write device id xx-xxxxxxxxxxxx to remove slave\n");
 472         return PAGE_SIZE - c;
 473 }
 474
 475 static ssize_t w1_master_attribute_store_remove(struct device *dev,
 476                                                 struct device_attribute *attr,
 477                                                 const char *buf, size_t count)
 478 {
 479         struct w1_master *md = dev_to_w1_master(dev);
 480         struct w1_reg_num rn;
 481         struct w1_slave *sl;
 482         ssize_t result = count;
 483
 484         if (w1_atoreg_num(dev, buf, count, &rn))
 485                 return -EINVAL;
 486
 487         mutex_lock(&md->mutex);
 488         sl = w1_slave_search_device(md, &rn);
 489         if (sl) {
 490                 w1_slave_detach(sl);
 491         } else {
 492                 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
 493                         (unsigned long long)rn.id);
 494                 result = -EINVAL;
 495         }
 496         mutex_unlock(&md->mutex);
 497
 498         return result;
 499 }
 500
 501 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 502         struct device_attribute w1_master_attribute_##_name =   \
 503                 __ATTR(w1_master_##_name, _mode,                \
 504                        w1_master_attribute_show_##_name, NULL)
 505
 506 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 507         struct device_attribute w1_master_attribute_##_name =   \
 508                 __ATTR(w1_master_##_name, _mode,                \
 509                        w1_master_attribute_show_##_name,        \
 510                        w1_master_attribute_store_##_name)
 511
 512 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 513 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 514 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 515 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 516 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 517 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 518 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 519 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
 520 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
 521 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
 522 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
 523
 524 static struct attribute *w1_master_default_attrs[] = {
 525         &w1_master_attribute_name.attr,
 526         &w1_master_attribute_slaves.attr,
 527         &w1_master_attribute_slave_count.attr,
 528         &w1_master_attribute_max_slave_count.attr,
 529         &w1_master_attribute_attempts.attr,
 530         &w1_master_attribute_timeout.attr,
 531         &w1_master_attribute_pointer.attr,
 532         &w1_master_attribute_search.attr,
 533         &w1_master_attribute_pullup.attr,
 534         &w1_master_attribute_add.attr,
 535         &w1_master_attribute_remove.attr,
 536         NULL
 537 };
 538
 539 static struct attribute_group w1_master_defattr_group = {
 540         .attrs = w1_master_default_attrs,
 541 };
 542
 543 int w1_create_master_attributes(struct w1_master *master)
 544 {
 545         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 546 }
 547
 548 void w1_destroy_master_attributes(struct w1_master *master)
 549 {
 550         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 551 }
 552
 553 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 554 {
 555         struct w1_master *md = NULL;
 556         struct w1_slave *sl = NULL;
 557         char *event_owner, *name;
 558         int err = 0;
 559
 560         if (dev->driver == &w1_master_driver) {
 561                 md = container_of(dev, struct w1_master, dev);
 562                 event_owner = "master";
 563                 name = md->name;
 564         } else if (dev->driver == &w1_slave_driver) {
 565                 sl = container_of(dev, struct w1_slave, dev);
 566                 event_owner = "slave";
 567                 name = sl->name;
 568         } else {
 569                 dev_dbg(dev, "Unknown event.\n");
 570                 return -EINVAL;
 571         }
 572
 573         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 574                         event_owner, name, dev_name(dev));
 575
 576         if (dev->driver != &w1_slave_driver || !sl)
 577                 goto end;
 578
 579         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 580         if (err)
 581                 goto end;
 582
 583         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 584                              (unsigned long long)sl->reg_num.id);
 585 end:
 586         return err;
 587 }
 588
 589 /*
 590  * Handle sysfs file creation and removal here, before userspace is told that
 591  * the device is added / removed from the system
 592  */
 593 static int w1_bus_notify(struct notifier_block *nb, unsigned long action,
 594                          void *data)
 595 {
 596         struct device *dev = data;
 597         struct w1_slave *sl;
 598         struct w1_family_ops *fops;
 599         int err;
 600
 601         /*
 602          * Only care about slave devices at the moment.  Yes, we should use a
 603          * separate "type" for this, but for now, look at the release function
 604          * to know which type it is...
 605          */
 606         if (dev->release != w1_slave_release)
 607                 return 0;
 608
 609         sl = dev_to_w1_slave(dev);
 610         fops = sl->family->fops;
 611
 612         switch (action) {
 613         case BUS_NOTIFY_ADD_DEVICE:
 614                 /* if the family driver needs to initialize something... */
 615                 if (fops->add_slave) {
 616                         err = fops->add_slave(sl);
 617                         if (err < 0) {
 618                                 dev_err(&sl->dev,
 619                                         "add_slave() call failed. err=%d\n",
 620                                         err);
 621                                 return err;
 622                         }
 623                 }
 624                 if (fops->groups) {
 625                         err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
 626                         if (err) {
 627                                 dev_err(&sl->dev,
 628                                         "sysfs group creation failed. err=%d\n",
 629                                         err);
 630                                 return err;
 631                         }
 632                 }
 633
 634                 break;
 635         case BUS_NOTIFY_DEL_DEVICE:
 636                 if (fops->remove_slave)
 637                         sl->family->fops->remove_slave(sl);
 638                 if (fops->groups)
 639                         sysfs_remove_groups(&sl->dev.kobj, fops->groups);
 640                 break;
 641         }
 642         return 0;
 643 }
 644
 645 static struct notifier_block w1_bus_nb = {
 646         .notifier_call = w1_bus_notify,
 647 };
 648
 649 static int __w1_attach_slave_device(struct w1_slave *sl)
 650 {
 651         int err;
 652
 653         sl->dev.parent = &sl->master->dev;
 654         sl->dev.driver = &w1_slave_driver;
 655         sl->dev.bus = &w1_bus_type;
 656         sl->dev.release = &w1_slave_release;
 657         sl->dev.groups = w1_slave_groups;
 658
 659         dev_set_name(&sl->dev, "%02x-%012llx",
 660                  (unsigned int) sl->reg_num.family,
 661                  (unsigned long long) sl->reg_num.id);
 662         snprintf(&sl->name[0], sizeof(sl->name),
 663                  "%02x-%012llx",
 664                  (unsigned int) sl->reg_num.family,
 665                  (unsigned long long) sl->reg_num.id);
 666
 667         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 668                 dev_name(&sl->dev), sl);
 669
 670         err = device_register(&sl->dev);
 671         if (err < 0) {
 672                 dev_err(&sl->dev,
 673                         "Device registration [%s] failed. err=%d\n",
 674                         dev_name(&sl->dev), err);
 675                 return err;
 676         }
 677
 678
 679         dev_set_uevent_suppress(&sl->dev, false);
 680         kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
 681
 682         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 683
 684         return 0;
 685 }
 686
 687 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 688 {
 689         struct w1_slave *sl;
 690         struct w1_family *f;
 691         int err;
 692         struct w1_netlink_msg msg;
 693
 694         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 695         if (!sl) {
 696                 dev_err(&dev->dev,
 697                          "%s: failed to allocate new slave device.\n",
 698                          __func__);
 699                 return -ENOMEM;
 700         }
 701
 702
 703         sl->owner = THIS_MODULE;
 704         sl->master = dev;
 705         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 706
 707         memset(&msg, 0, sizeof(msg));
 708         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 709         atomic_set(&sl->refcnt, 0);
 710         init_completion(&sl->released);
 711
 712         request_module("w1-family-0x%0x", rn->family);
 713
 714         spin_lock(&w1_flock);
 715         f = w1_family_registered(rn->family);
 716         if (!f) {
 717                 f= &w1_default_family;
 718                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 719                           rn->family, rn->family,
 720                           (unsigned long long)rn->id, rn->crc);
 721         }
 722         __w1_family_get(f);
 723         spin_unlock(&w1_flock);
 724
 725         sl->family = f;
 726
 727
 728         err = __w1_attach_slave_device(sl);
 729         if (err < 0) {
 730                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 731                          sl->name);
 732                 w1_family_put(sl->family);
 733                 kfree(sl);
 734                 return err;
 735         }
 736
 737         sl->ttl = dev->slave_ttl;
 738         dev->slave_count++;
 739
 740         memcpy(msg.id.id, rn, sizeof(msg.id));
 741         msg.type = W1_SLAVE_ADD;
 742         w1_netlink_send(dev, &msg);
 743
 744         return 0;
 745 }
 746
 747 void w1_slave_detach(struct w1_slave *sl)
 748 {
 749         struct w1_netlink_msg msg;
 750
 751         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 752
 753         list_del(&sl->w1_slave_entry);
 754
 755         memset(&msg, 0, sizeof(msg));
 756         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 757         msg.type = W1_SLAVE_REMOVE;
 758         w1_netlink_send(sl->master, &msg);
 759
 760         device_unregister(&sl->dev);
 761
 762         wait_for_completion(&sl->released);
 763         kfree(sl);
 764 }
 765
 766 struct w1_master *w1_search_master_id(u32 id)
 767 {
 768         struct w1_master *dev;
 769         int found = 0;
 770
 771         mutex_lock(&w1_mlock);
 772         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 773                 if (dev->id == id) {
 774                         found = 1;
 775                         atomic_inc(&dev->refcnt);
 776                         break;
 777                 }
 778         }
 779         mutex_unlock(&w1_mlock);
 780
 781         return (found)?dev:NULL;
 782 }
 783
 784 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 785 {
 786         struct w1_master *dev;
 787         struct w1_slave *sl = NULL;
 788         int found = 0;
 789
 790         mutex_lock(&w1_mlock);
 791         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 792                 mutex_lock(&dev->mutex);
 793                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 794                         if (sl->reg_num.family == id->family &&
 795                                         sl->reg_num.id == id->id &&
 796                                         sl->reg_num.crc == id->crc) {
 797                                 found = 1;
 798                                 atomic_inc(&dev->refcnt);
 799                                 atomic_inc(&sl->refcnt);
 800                                 break;
 801                         }
 802                 }
 803                 mutex_unlock(&dev->mutex);
 804
 805                 if (found)
 806                         break;
 807         }
 808         mutex_unlock(&w1_mlock);
 809
 810         return (found)?sl:NULL;
 811 }
 812
 813 void w1_reconnect_slaves(struct w1_family *f, int attach)
 814 {
 815         struct w1_slave *sl, *sln;
 816         struct w1_master *dev;
 817
 818         mutex_lock(&w1_mlock);
 819         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 820                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 821                         "for family %02x.\n", dev->name, f->fid);
 822                 mutex_lock(&dev->mutex);
 823                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 824                         /* If it is a new family, slaves with the default
 825                          * family driver and are that family will be
 826                          * connected.  If the family is going away, devices
 827                          * matching that family are reconneced.
 828                          */
 829                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 830                                 && sl->reg_num.family == f->fid) ||
 831                                 (!attach && sl->family->fid == f->fid)) {
 832                                 struct w1_reg_num rn;
 833
 834                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 835                                 w1_slave_detach(sl);
 836
 837                                 w1_attach_slave_device(dev, &rn);
 838                         }
 839                 }
 840                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 841                         "has been finished.\n", dev->name);
 842                 mutex_unlock(&dev->mutex);
 843         }
 844         mutex_unlock(&w1_mlock);
 845 }
 846
 847 void w1_slave_found(struct w1_master *dev, u64 rn)
 848 {
 849         struct w1_slave *sl;
 850         struct w1_reg_num *tmp;
 851         u64 rn_le = cpu_to_le64(rn);
 852
 853         atomic_inc(&dev->refcnt);
 854
 855         tmp = (struct w1_reg_num *) &rn;
 856
 857         sl = w1_slave_search_device(dev, tmp);
 858         if (sl) {
 859                 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 860         } else {
 861                 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
 862                         w1_attach_slave_device(dev, tmp);
 863         }
 864
 865         atomic_dec(&dev->refcnt);
 866 }
 867
 868 /**
 869  * Performs a ROM Search & registers any devices found.
 870  * The 1-wire search is a simple binary tree search.
 871  * For each bit of the address, we read two bits and write one bit.
 872  * The bit written will put to sleep all devies that don't match that bit.
 873  * When the two reads differ, the direction choice is obvious.
 874  * When both bits are 0, we must choose a path to take.
 875  * When we can scan all 64 bits without having to choose a path, we are done.
 876  *
 877  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 878  *
 879  * @dev        The master device to search
 880  * @cb         Function to call when a device is found
 881  */
 882 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 883 {
 884         u64 last_rn, rn, tmp64;
 885         int i, slave_count = 0;
 886         int last_zero, last_device;
 887         int search_bit, desc_bit;
 888         u8  triplet_ret = 0;
 889
 890         search_bit = 0;
 891         rn = last_rn = 0;
 892         last_device = 0;
 893         last_zero = -1;
 894
 895         desc_bit = 64;
 896
 897         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 898                 last_rn = rn;
 899                 rn = 0;
 900
 901                 /*
 902                  * Reset bus and all 1-wire device state machines
 903                  * so they can respond to our requests.
 904                  *
 905                  * Return 0 - device(s) present, 1 - no devices present.
 906                  */
 907                 mutex_lock(&dev->bus_mutex);
 908                 if (w1_reset_bus(dev)) {
 909                         mutex_unlock(&dev->bus_mutex);
 910                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 911                         break;
 912                 }
 913
 914                 /* Do fast search on single slave bus */
 915                 if (dev->max_slave_count == 1) {
 916                         int rv;
 917                         w1_write_8(dev, W1_READ_ROM);
 918                         rv = w1_read_block(dev, (u8 *)&rn, 8);
 919                         mutex_unlock(&dev->bus_mutex);
 920
 921                         if (rv == 8 && rn)
 922                                 cb(dev, rn);
 923
 924                         break;
 925                 }
 926
 927                 /* Start the search */
 928                 w1_write_8(dev, search_type);
 929                 for (i = 0; i < 64; ++i) {
 930                         /* Determine the direction/search bit */
 931                         if (i == desc_bit)
 932                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 933                         else if (i > desc_bit)
 934                                 search_bit = 0;   /* take the 0 path on the next branch */
 935                         else
 936                                 search_bit = ((last_rn >> i) & 0x1);
 937
 938                         /** Read two bits and write one bit */
 939                         triplet_ret = w1_triplet(dev, search_bit);
 940
 941                         /* quit if no device responded */
 942                         if ( (triplet_ret & 0x03) == 0x03 )
 943                                 break;
 944
 945                         /* If both directions were valid, and we took the 0 path... */
 946                         if (triplet_ret == 0)
 947                                 last_zero = i;
 948
 949                         /* extract the direction taken & update the device number */
 950                         tmp64 = (triplet_ret >> 2);
 951                         rn |= (tmp64 << i);
 952
 953                         /* ensure we're called from kthread and not by netlink callback */
 954                         if (!dev->priv && kthread_should_stop()) {
 955                                 mutex_unlock(&dev->bus_mutex);
 956                                 dev_dbg(&dev->dev, "Abort w1_search\n");
 957                                 return;
 958                         }
 959                 }
 960                 mutex_unlock(&dev->bus_mutex);
 961
 962                 if ( (triplet_ret & 0x03) != 0x03 ) {
 963                         if ( (desc_bit == last_zero) || (last_zero < 0))
 964                                 last_device = 1;
 965                         desc_bit = last_zero;
 966                         cb(dev, rn);
 967                 }
 968         }
 969 }
 970
 971 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
 972         w1_slave_found_callback cb)
 973 {
 974         struct w1_slave *sl, *sln;
 975
 976         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 977                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 978
 979         w1_search_devices(dev, search_type, cb);
 980
 981         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 982                 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
 983                         w1_slave_detach(sl);
 984                 else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 985                         sl->ttl = dev->slave_ttl;
 986         }
 987
 988         if (dev->search_count > 0)
 989                 dev->search_count--;
 990 }
 991
 992 static void w1_search_process(struct w1_master *dev, u8 search_type)
 993 {
 994         w1_search_process_cb(dev, search_type, w1_slave_found);
 995 }
 996
 997 int w1_process(void *data)
 998 {
 999         struct w1_master *dev = (struct w1_master *) data;
1000         /* As long as w1_timeout is only set by a module parameter the sleep
1001          * time can be calculated in jiffies once.
1002          */
1003         const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
1004
1005         while (!kthread_should_stop()) {
1006                 if (dev->search_count) {
1007                         mutex_lock(&dev->mutex);
1008                         w1_search_process(dev, W1_SEARCH);
1009                         mutex_unlock(&dev->mutex);
1010                 }
1011
1012                 try_to_freeze();
1013                 __set_current_state(TASK_INTERRUPTIBLE);
1014
1015                 if (kthread_should_stop())
1016                         break;
1017
1018                 /* Only sleep when the search is active. */
1019                 if (dev->search_count)
1020                         schedule_timeout(jtime);
1021                 else
1022                         schedule();
1023         }
1024
1025         atomic_dec(&dev->refcnt);
1026
1027         return 0;
1028 }
1029
1030 static int __init w1_init(void)
1031 {
1032         int retval;
1033
1034         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
1035
1036         w1_init_netlink();
1037
1038         retval = bus_register(&w1_bus_type);
1039         if (retval) {
1040                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
1041                 goto err_out_exit_init;
1042         }
1043
1044         retval = bus_register_notifier(&w1_bus_type, &w1_bus_nb);
1045         if (retval)
1046                 goto err_out_bus_unregister;
1047
1048         retval = driver_register(&w1_master_driver);
1049         if (retval) {
1050                 printk(KERN_ERR
1051                         "Failed to register master driver. err=%d.\n",
1052                         retval);
1053                 goto err_out_bus_unregister;
1054         }
1055
1056         retval = driver_register(&w1_slave_driver);
1057         if (retval) {
1058                 printk(KERN_ERR
1059                         "Failed to register slave driver. err=%d.\n",
1060                         retval);
1061                 goto err_out_master_unregister;
1062         }
1063
1064         return 0;
1065
1066 #if 0
1067 /* For undoing the slave register if there was a step after it. */
1068 err_out_slave_unregister:
1069         driver_unregister(&w1_slave_driver);
1070 #endif
1071
1072 err_out_master_unregister:
1073         driver_unregister(&w1_master_driver);
1074
1075 err_out_bus_unregister:
1076         bus_unregister(&w1_bus_type);
1077
1078 err_out_exit_init:
1079         return retval;
1080 }
1081
1082 static void __exit w1_fini(void)
1083 {
1084         struct w1_master *dev;
1085
1086         /* Set netlink removal messages and some cleanup */
1087         list_for_each_entry(dev, &w1_masters, w1_master_entry)
1088                 __w1_remove_master_device(dev);
1089
1090         w1_fini_netlink();
1091
1092         driver_unregister(&w1_slave_driver);
1093         driver_unregister(&w1_master_driver);
1094         bus_unregister(&w1_bus_type);
1095 }
1096
1097 module_init(w1_init);
1098 module_exit(w1_fini);