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 = 64;
  50 int w1_max_slave_ttl = 10;
  51
  52 module_param_named(timeout, w1_timeout, int, 0);
  53 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  54 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  55
  56 DEFINE_MUTEX(w1_mlock);
  57 LIST_HEAD(w1_masters);
  58
  59 static int w1_master_match(struct device *dev, struct device_driver *drv)
  60 {
  61         return 1;
  62 }
  63
  64 static int w1_master_probe(struct device *dev)
  65 {
  66         return -ENODEV;
  67 }
  68
  69 static void w1_master_release(struct device *dev)
  70 {
  71         struct w1_master *md = dev_to_w1_master(dev);
  72
  73         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  74         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  75         kfree(md);
  76 }
  77
  78 static void w1_slave_release(struct device *dev)
  79 {
  80         struct w1_slave *sl = dev_to_w1_slave(dev);
  81
  82         dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);
  83
  84         w1_family_put(sl->family);
  85         sl->master->slave_count--;
  86 }
  87
  88 static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
  89 {
  90         struct w1_slave *sl = dev_to_w1_slave(dev);
  91
  92         return sprintf(buf, "%s\n", sl->name);
  93 }
  94 static DEVICE_ATTR_RO(name);
  95
  96 static ssize_t id_show(struct device *dev,
  97         struct device_attribute *attr, char *buf)
  98 {
  99         struct w1_slave *sl = dev_to_w1_slave(dev);
 100         ssize_t count = sizeof(sl->reg_num);
 101
 102         memcpy(buf, (u8 *)&sl->reg_num, count);
 103         return count;
 104 }
 105 static DEVICE_ATTR_RO(id);
 106
 107 static struct attribute *w1_slave_attrs[] = {
 108         &dev_attr_name.attr,
 109         &dev_attr_id.attr,
 110         NULL,
 111 };
 112 ATTRIBUTE_GROUPS(w1_slave);
 113
 114 /* Default family */
 115
 116 static ssize_t rw_write(struct file *filp, struct kobject *kobj,
 117                         struct bin_attribute *bin_attr, char *buf, loff_t off,
 118                         size_t count)
 119 {
 120         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 121
 122         mutex_lock(&sl->master->mutex);
 123         if (w1_reset_select_slave(sl)) {
 124                 count = 0;
 125                 goto out_up;
 126         }
 127
 128         w1_write_block(sl->master, buf, count);
 129
 130 out_up:
 131         mutex_unlock(&sl->master->mutex);
 132         return count;
 133 }
 134
 135 static ssize_t rw_read(struct file *filp, struct kobject *kobj,
 136                        struct bin_attribute *bin_attr, char *buf, loff_t off,
 137                        size_t count)
 138 {
 139         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 140
 141         mutex_lock(&sl->master->mutex);
 142         w1_read_block(sl->master, buf, count);
 143         mutex_unlock(&sl->master->mutex);
 144         return count;
 145 }
 146
 147 static BIN_ATTR_RW(rw, PAGE_SIZE);
 148
 149 static struct bin_attribute *w1_slave_bin_attrs[] = {
 150         &bin_attr_rw,
 151         NULL,
 152 };
 153
 154 static const struct attribute_group w1_slave_default_group = {
 155         .bin_attrs = w1_slave_bin_attrs,
 156 };
 157
 158 static const struct attribute_group *w1_slave_default_groups[] = {
 159         &w1_slave_default_group,
 160         NULL,
 161 };
 162
 163 static struct w1_family_ops w1_default_fops = {
 164         .groups         = w1_slave_default_groups,
 165 };
 166
 167 static struct w1_family w1_default_family = {
 168         .fops = &w1_default_fops,
 169 };
 170
 171 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 172
 173 static struct bus_type w1_bus_type = {
 174         .name = "w1",
 175         .match = w1_master_match,
 176         .uevent = w1_uevent,
 177 };
 178
 179 struct device_driver w1_master_driver = {
 180         .name = "w1_master_driver",
 181         .bus = &w1_bus_type,
 182         .probe = w1_master_probe,
 183 };
 184
 185 struct device w1_master_device = {
 186         .parent = NULL,
 187         .bus = &w1_bus_type,
 188         .init_name = "w1 bus master",
 189         .driver = &w1_master_driver,
 190         .release = &w1_master_release
 191 };
 192
 193 static struct device_driver w1_slave_driver = {
 194         .name = "w1_slave_driver",
 195         .bus = &w1_bus_type,
 196 };
 197
 198 #if 0
 199 struct device w1_slave_device = {
 200         .parent = NULL,
 201         .bus = &w1_bus_type,
 202         .init_name = "w1 bus slave",
 203         .driver = &w1_slave_driver,
 204         .release = &w1_slave_release
 205 };
 206 #endif  /*  0  */
 207
 208 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 209 {
 210         struct w1_master *md = dev_to_w1_master(dev);
 211         ssize_t count;
 212
 213         mutex_lock(&md->mutex);
 214         count = sprintf(buf, "%s\n", md->name);
 215         mutex_unlock(&md->mutex);
 216
 217         return count;
 218 }
 219
 220 static ssize_t w1_master_attribute_store_search(struct device * dev,
 221                                                 struct device_attribute *attr,
 222                                                 const char * buf, size_t count)
 223 {
 224         long tmp;
 225         struct w1_master *md = dev_to_w1_master(dev);
 226         int ret;
 227
 228         ret = kstrtol(buf, 0, &tmp);
 229         if (ret)
 230                 return ret;
 231
 232         mutex_lock(&md->mutex);
 233         md->search_count = tmp;
 234         mutex_unlock(&md->mutex);
 235         /* Only wake if it is going to be searching. */
 236         if (tmp)
 237                 wake_up_process(md->thread);
 238
 239         return count;
 240 }
 241
 242 static ssize_t w1_master_attribute_show_search(struct device *dev,
 243                                                struct device_attribute *attr,
 244                                                char *buf)
 245 {
 246         struct w1_master *md = dev_to_w1_master(dev);
 247         ssize_t count;
 248
 249         mutex_lock(&md->mutex);
 250         count = sprintf(buf, "%d\n", md->search_count);
 251         mutex_unlock(&md->mutex);
 252
 253         return count;
 254 }
 255
 256 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
 257                                                 struct device_attribute *attr,
 258                                                 const char *buf, size_t count)
 259 {
 260         long tmp;
 261         struct w1_master *md = dev_to_w1_master(dev);
 262         int ret;
 263
 264         ret = kstrtol(buf, 0, &tmp);
 265         if (ret)
 266                 return ret;
 267
 268         mutex_lock(&md->mutex);
 269         md->enable_pullup = tmp;
 270         mutex_unlock(&md->mutex);
 271
 272         return count;
 273 }
 274
 275 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
 276                                                struct device_attribute *attr,
 277                                                char *buf)
 278 {
 279         struct w1_master *md = dev_to_w1_master(dev);
 280         ssize_t count;
 281
 282         mutex_lock(&md->mutex);
 283         count = sprintf(buf, "%d\n", md->enable_pullup);
 284         mutex_unlock(&md->mutex);
 285
 286         return count;
 287 }
 288
 289 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 290 {
 291         struct w1_master *md = dev_to_w1_master(dev);
 292         ssize_t count;
 293
 294         mutex_lock(&md->mutex);
 295         count = sprintf(buf, "0x%p\n", md->bus_master);
 296         mutex_unlock(&md->mutex);
 297         return count;
 298 }
 299
 300 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 301 {
 302         ssize_t count;
 303         count = sprintf(buf, "%d\n", w1_timeout);
 304         return count;
 305 }
 306
 307 static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,
 308         struct device_attribute *attr, const char *buf, size_t count)
 309 {
 310         long tmp;
 311         struct w1_master *md = dev_to_w1_master(dev);
 312
 313         if (kstrtol(buf, 0, &tmp) == -EINVAL || tmp < 1)
 314                 return -EINVAL;
 315
 316         mutex_lock(&md->mutex);
 317         md->max_slave_count = tmp;
 318         /* allow each time the max_slave_count is updated */
 319         clear_bit(W1_WARN_MAX_COUNT, &md->flags);
 320         mutex_unlock(&md->mutex);
 321
 322         return count;
 323 }
 324
 325 static ssize_t w1_master_attribute_show_max_slave_count(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, "%d\n", md->max_slave_count);
 332         mutex_unlock(&md->mutex);
 333         return count;
 334 }
 335
 336 static ssize_t w1_master_attribute_show_attempts(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, "%lu\n", md->attempts);
 343         mutex_unlock(&md->mutex);
 344         return count;
 345 }
 346
 347 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 348 {
 349         struct w1_master *md = dev_to_w1_master(dev);
 350         ssize_t count;
 351
 352         mutex_lock(&md->mutex);
 353         count = sprintf(buf, "%d\n", md->slave_count);
 354         mutex_unlock(&md->mutex);
 355         return count;
 356 }
 357
 358 static ssize_t w1_master_attribute_show_slaves(struct device *dev,
 359         struct device_attribute *attr, char *buf)
 360 {
 361         struct w1_master *md = dev_to_w1_master(dev);
 362         int c = PAGE_SIZE;
 363         struct list_head *ent, *n;
 364         struct w1_slave *sl = NULL;
 365
 366         mutex_lock(&md->list_mutex);
 367
 368         list_for_each_safe(ent, n, &md->slist) {
 369                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 370
 371                 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 372         }
 373         if (!sl)
 374                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 375
 376         mutex_unlock(&md->list_mutex);
 377
 378         return PAGE_SIZE - c;
 379 }
 380
 381 static ssize_t w1_master_attribute_show_add(struct device *dev,
 382         struct device_attribute *attr, char *buf)
 383 {
 384         int c = PAGE_SIZE;
 385         c -= snprintf(buf+PAGE_SIZE - c, c,
 386                 "write device id xx-xxxxxxxxxxxx to add slave\n");
 387         return PAGE_SIZE - c;
 388 }
 389
 390 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
 391         struct w1_reg_num *rn)
 392 {
 393         unsigned int family;
 394         unsigned long long id;
 395         int i;
 396         u64 rn64_le;
 397
 398         /* The CRC value isn't read from the user because the sysfs directory
 399          * doesn't include it and most messages from the bus search don't
 400          * print it either.  It would be unreasonable for the user to then
 401          * provide it.
 402          */
 403         const char *error_msg = "bad slave string format, expecting "
 404                 "ff-dddddddddddd\n";
 405
 406         if (buf[2] != '-') {
 407                 dev_err(dev, "%s", error_msg);
 408                 return -EINVAL;
 409         }
 410         i = sscanf(buf, "%02x-%012llx", &family, &id);
 411         if (i != 2) {
 412                 dev_err(dev, "%s", error_msg);
 413                 return -EINVAL;
 414         }
 415         rn->family = family;
 416         rn->id = id;
 417
 418         rn64_le = cpu_to_le64(*(u64 *)rn);
 419         rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
 420
 421 #if 0
 422         dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
 423                   rn->family, (unsigned long long)rn->id, rn->crc);
 424 #endif
 425
 426         return 0;
 427 }
 428
 429 /* Searches the slaves in the w1_master and returns a pointer or NULL.
 430  * Note: must not hold list_mutex
 431  */
 432 struct w1_slave *w1_slave_search_device(struct w1_master *dev,
 433         struct w1_reg_num *rn)
 434 {
 435         struct w1_slave *sl;
 436         mutex_lock(&dev->list_mutex);
 437         list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 438                 if (sl->reg_num.family == rn->family &&
 439                                 sl->reg_num.id == rn->id &&
 440                                 sl->reg_num.crc == rn->crc) {
 441                         mutex_unlock(&dev->list_mutex);
 442                         return sl;
 443                 }
 444         }
 445         mutex_unlock(&dev->list_mutex);
 446         return NULL;
 447 }
 448
 449 static ssize_t w1_master_attribute_store_add(struct device *dev,
 450                                                 struct device_attribute *attr,
 451                                                 const char *buf, size_t count)
 452 {
 453         struct w1_master *md = dev_to_w1_master(dev);
 454         struct w1_reg_num rn;
 455         struct w1_slave *sl;
 456         ssize_t result = count;
 457
 458         if (w1_atoreg_num(dev, buf, count, &rn))
 459                 return -EINVAL;
 460
 461         mutex_lock(&md->mutex);
 462         sl = w1_slave_search_device(md, &rn);
 463         /* It would be nice to do a targeted search one the one-wire bus
 464          * for the new device to see if it is out there or not.  But the
 465          * current search doesn't support that.
 466          */
 467         if (sl) {
 468                 dev_info(dev, "Device %s already exists\n", sl->name);
 469                 result = -EINVAL;
 470         } else {
 471                 w1_attach_slave_device(md, &rn);
 472         }
 473         mutex_unlock(&md->mutex);
 474
 475         return result;
 476 }
 477
 478 static ssize_t w1_master_attribute_show_remove(struct device *dev,
 479         struct device_attribute *attr, char *buf)
 480 {
 481         int c = PAGE_SIZE;
 482         c -= snprintf(buf+PAGE_SIZE - c, c,
 483                 "write device id xx-xxxxxxxxxxxx to remove slave\n");
 484         return PAGE_SIZE - c;
 485 }
 486
 487 static ssize_t w1_master_attribute_store_remove(struct device *dev,
 488                                                 struct device_attribute *attr,
 489                                                 const char *buf, size_t count)
 490 {
 491         struct w1_master *md = dev_to_w1_master(dev);
 492         struct w1_reg_num rn;
 493         struct w1_slave *sl;
 494         ssize_t result = count;
 495
 496         if (w1_atoreg_num(dev, buf, count, &rn))
 497                 return -EINVAL;
 498
 499         mutex_lock(&md->mutex);
 500         sl = w1_slave_search_device(md, &rn);
 501         if (sl) {
 502                 result = w1_slave_detach(sl);
 503                 /* refcnt 0 means it was detached in the call */
 504                 if (result == 0)
 505                         result = count;
 506         } else {
 507                 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
 508                         (unsigned long long)rn.id);
 509                 result = -EINVAL;
 510         }
 511         mutex_unlock(&md->mutex);
 512
 513         return result;
 514 }
 515
 516 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 517         struct device_attribute w1_master_attribute_##_name =   \
 518                 __ATTR(w1_master_##_name, _mode,                \
 519                        w1_master_attribute_show_##_name, NULL)
 520
 521 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 522         struct device_attribute w1_master_attribute_##_name =   \
 523                 __ATTR(w1_master_##_name, _mode,                \
 524                        w1_master_attribute_show_##_name,        \
 525                        w1_master_attribute_store_##_name)
 526
 527 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 528 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 529 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 530 static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);
 531 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 532 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 533 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 534 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
 535 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
 536 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
 537 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
 538
 539 static struct attribute *w1_master_default_attrs[] = {
 540         &w1_master_attribute_name.attr,
 541         &w1_master_attribute_slaves.attr,
 542         &w1_master_attribute_slave_count.attr,
 543         &w1_master_attribute_max_slave_count.attr,
 544         &w1_master_attribute_attempts.attr,
 545         &w1_master_attribute_timeout.attr,
 546         &w1_master_attribute_pointer.attr,
 547         &w1_master_attribute_search.attr,
 548         &w1_master_attribute_pullup.attr,
 549         &w1_master_attribute_add.attr,
 550         &w1_master_attribute_remove.attr,
 551         NULL
 552 };
 553
 554 static struct attribute_group w1_master_defattr_group = {
 555         .attrs = w1_master_default_attrs,
 556 };
 557
 558 int w1_create_master_attributes(struct w1_master *master)
 559 {
 560         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 561 }
 562
 563 void w1_destroy_master_attributes(struct w1_master *master)
 564 {
 565         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 566 }
 567
 568 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 569 {
 570         struct w1_master *md = NULL;
 571         struct w1_slave *sl = NULL;
 572         char *event_owner, *name;
 573         int err = 0;
 574
 575         if (dev->driver == &w1_master_driver) {
 576                 md = container_of(dev, struct w1_master, dev);
 577                 event_owner = "master";
 578                 name = md->name;
 579         } else if (dev->driver == &w1_slave_driver) {
 580                 sl = container_of(dev, struct w1_slave, dev);
 581                 event_owner = "slave";
 582                 name = sl->name;
 583         } else {
 584                 dev_dbg(dev, "Unknown event.\n");
 585                 return -EINVAL;
 586         }
 587
 588         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 589                         event_owner, name, dev_name(dev));
 590
 591         if (dev->driver != &w1_slave_driver || !sl)
 592                 goto end;
 593
 594         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 595         if (err)
 596                 goto end;
 597
 598         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 599                              (unsigned long long)sl->reg_num.id);
 600 end:
 601         return err;
 602 }
 603
 604 /*
 605  * Handle sysfs file creation and removal here, before userspace is told that
 606  * the device is added / removed from the system
 607  */
 608 static int w1_bus_notify(struct notifier_block *nb, unsigned long action,
 609                          void *data)
 610 {
 611         struct device *dev = data;
 612         struct w1_slave *sl;
 613         struct w1_family_ops *fops;
 614         int err;
 615
 616         /*
 617          * Only care about slave devices at the moment.  Yes, we should use a
 618          * separate "type" for this, but for now, look at the release function
 619          * to know which type it is...
 620          */
 621         if (dev->release != w1_slave_release)
 622                 return 0;
 623
 624         sl = dev_to_w1_slave(dev);
 625         fops = sl->family->fops;
 626
 627         if (!fops)
 628                 return 0;
 629
 630         switch (action) {
 631         case BUS_NOTIFY_ADD_DEVICE:
 632                 /* if the family driver needs to initialize something... */
 633                 if (fops->add_slave) {
 634                         err = fops->add_slave(sl);
 635                         if (err < 0) {
 636                                 dev_err(&sl->dev,
 637                                         "add_slave() call failed. err=%d\n",
 638                                         err);
 639                                 return err;
 640                         }
 641                 }
 642                 if (fops->groups) {
 643                         err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
 644                         if (err) {
 645                                 dev_err(&sl->dev,
 646                                         "sysfs group creation failed. err=%d\n",
 647                                         err);
 648                                 return err;
 649                         }
 650                 }
 651
 652                 break;
 653         case BUS_NOTIFY_DEL_DEVICE:
 654                 if (fops->remove_slave)
 655                         sl->family->fops->remove_slave(sl);
 656                 if (fops->groups)
 657                         sysfs_remove_groups(&sl->dev.kobj, fops->groups);
 658                 break;
 659         }
 660         return 0;
 661 }
 662
 663 static struct notifier_block w1_bus_nb = {
 664         .notifier_call = w1_bus_notify,
 665 };
 666
 667 static int __w1_attach_slave_device(struct w1_slave *sl)
 668 {
 669         int err;
 670
 671         sl->dev.parent = &sl->master->dev;
 672         sl->dev.driver = &w1_slave_driver;
 673         sl->dev.bus = &w1_bus_type;
 674         sl->dev.release = &w1_slave_release;
 675         sl->dev.groups = w1_slave_groups;
 676
 677         dev_set_name(&sl->dev, "%02x-%012llx",
 678                  (unsigned int) sl->reg_num.family,
 679                  (unsigned long long) sl->reg_num.id);
 680         snprintf(&sl->name[0], sizeof(sl->name),
 681                  "%02x-%012llx",
 682                  (unsigned int) sl->reg_num.family,
 683                  (unsigned long long) sl->reg_num.id);
 684
 685         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 686                 dev_name(&sl->dev), sl);
 687
 688         err = device_register(&sl->dev);
 689         if (err < 0) {
 690                 dev_err(&sl->dev,
 691                         "Device registration [%s] failed. err=%d\n",
 692                         dev_name(&sl->dev), err);
 693                 return err;
 694         }
 695
 696
 697         dev_set_uevent_suppress(&sl->dev, false);
 698         kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
 699
 700         mutex_lock(&sl->master->list_mutex);
 701         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 702         mutex_unlock(&sl->master->list_mutex);
 703
 704         return 0;
 705 }
 706
 707 int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 708 {
 709         struct w1_slave *sl;
 710         struct w1_family *f;
 711         int err;
 712         struct w1_netlink_msg msg;
 713
 714         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 715         if (!sl) {
 716                 dev_err(&dev->dev,
 717                          "%s: failed to allocate new slave device.\n",
 718                          __func__);
 719                 return -ENOMEM;
 720         }
 721
 722
 723         sl->owner = THIS_MODULE;
 724         sl->master = dev;
 725         set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 726
 727         memset(&msg, 0, sizeof(msg));
 728         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 729         atomic_set(&sl->refcnt, 1);
 730         atomic_inc(&sl->master->refcnt);
 731
 732         /* slave modules need to be loaded in a context with unlocked mutex */
 733         mutex_unlock(&dev->mutex);
 734         request_module("w1-family-0x%0x", rn->family);
 735         mutex_lock(&dev->mutex);
 736
 737         spin_lock(&w1_flock);
 738         f = w1_family_registered(rn->family);
 739         if (!f) {
 740                 f= &w1_default_family;
 741                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 742                           rn->family, rn->family,
 743                           (unsigned long long)rn->id, rn->crc);
 744         }
 745         __w1_family_get(f);
 746         spin_unlock(&w1_flock);
 747
 748         sl->family = f;
 749
 750
 751         err = __w1_attach_slave_device(sl);
 752         if (err < 0) {
 753                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 754                          sl->name);
 755                 w1_family_put(sl->family);
 756                 kfree(sl);
 757                 return err;
 758         }
 759
 760         sl->ttl = dev->slave_ttl;
 761         dev->slave_count++;
 762
 763         memcpy(msg.id.id, rn, sizeof(msg.id));
 764         msg.type = W1_SLAVE_ADD;
 765         w1_netlink_send(dev, &msg);
 766
 767         return 0;
 768 }
 769
 770 int w1_unref_slave(struct w1_slave *sl)
 771 {
 772         struct w1_master *dev = sl->master;
 773         int refcnt;
 774         mutex_lock(&dev->list_mutex);
 775         refcnt = atomic_sub_return(1, &sl->refcnt);
 776         if (refcnt == 0) {
 777                 struct w1_netlink_msg msg;
 778
 779                 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
 780                         sl->name, sl);
 781
 782                 list_del(&sl->w1_slave_entry);
 783
 784                 memset(&msg, 0, sizeof(msg));
 785                 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 786                 msg.type = W1_SLAVE_REMOVE;
 787                 w1_netlink_send(sl->master, &msg);
 788
 789                 device_unregister(&sl->dev);
 790                 #ifdef DEBUG
 791                 memset(sl, 0, sizeof(*sl));
 792                 #endif
 793                 kfree(sl);
 794         }
 795         atomic_dec(&dev->refcnt);
 796         mutex_unlock(&dev->list_mutex);
 797         return refcnt;
 798 }
 799
 800 int w1_slave_detach(struct w1_slave *sl)
 801 {
 802         /* Only detach a slave once as it decreases the refcnt each time. */
 803         int destroy_now;
 804         mutex_lock(&sl->master->list_mutex);
 805         destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
 806         set_bit(W1_SLAVE_DETACH, &sl->flags);
 807         mutex_unlock(&sl->master->list_mutex);
 808
 809         if (destroy_now)
 810                 destroy_now = !w1_unref_slave(sl);
 811         return destroy_now ? 0 : -EBUSY;
 812 }
 813
 814 struct w1_master *w1_search_master_id(u32 id)
 815 {
 816         struct w1_master *dev;
 817         int found = 0;
 818
 819         mutex_lock(&w1_mlock);
 820         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 821                 if (dev->id == id) {
 822                         found = 1;
 823                         atomic_inc(&dev->refcnt);
 824                         break;
 825                 }
 826         }
 827         mutex_unlock(&w1_mlock);
 828
 829         return (found)?dev:NULL;
 830 }
 831
 832 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 833 {
 834         struct w1_master *dev;
 835         struct w1_slave *sl = NULL;
 836         int found = 0;
 837
 838         mutex_lock(&w1_mlock);
 839         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 840                 mutex_lock(&dev->list_mutex);
 841                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 842                         if (sl->reg_num.family == id->family &&
 843                                         sl->reg_num.id == id->id &&
 844                                         sl->reg_num.crc == id->crc) {
 845                                 found = 1;
 846                                 atomic_inc(&dev->refcnt);
 847                                 atomic_inc(&sl->refcnt);
 848                                 break;
 849                         }
 850                 }
 851                 mutex_unlock(&dev->list_mutex);
 852
 853                 if (found)
 854                         break;
 855         }
 856         mutex_unlock(&w1_mlock);
 857
 858         return (found)?sl:NULL;
 859 }
 860
 861 void w1_reconnect_slaves(struct w1_family *f, int attach)
 862 {
 863         struct w1_slave *sl, *sln;
 864         struct w1_master *dev;
 865
 866         mutex_lock(&w1_mlock);
 867         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 868                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 869                         "for family %02x.\n", dev->name, f->fid);
 870                 mutex_lock(&dev->mutex);
 871                 mutex_lock(&dev->list_mutex);
 872                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 873                         /* If it is a new family, slaves with the default
 874                          * family driver and are that family will be
 875                          * connected.  If the family is going away, devices
 876                          * matching that family are reconneced.
 877                          */
 878                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 879                                 && sl->reg_num.family == f->fid) ||
 880                                 (!attach && sl->family->fid == f->fid)) {
 881                                 struct w1_reg_num rn;
 882
 883                                 mutex_unlock(&dev->list_mutex);
 884                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 885                                 /* If it was already in use let the automatic
 886                                  * scan pick it up again later.
 887                                  */
 888                                 if (!w1_slave_detach(sl))
 889                                         w1_attach_slave_device(dev, &rn);
 890                                 mutex_lock(&dev->list_mutex);
 891                         }
 892                 }
 893                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 894                         "has been finished.\n", dev->name);
 895                 mutex_unlock(&dev->list_mutex);
 896                 mutex_unlock(&dev->mutex);
 897         }
 898         mutex_unlock(&w1_mlock);
 899 }
 900
 901 void w1_slave_found(struct w1_master *dev, u64 rn)
 902 {
 903         struct w1_slave *sl;
 904         struct w1_reg_num *tmp;
 905         u64 rn_le = cpu_to_le64(rn);
 906
 907         atomic_inc(&dev->refcnt);
 908
 909         tmp = (struct w1_reg_num *) &rn;
 910
 911         sl = w1_slave_search_device(dev, tmp);
 912         if (sl) {
 913                 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 914         } else {
 915                 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
 916                         w1_attach_slave_device(dev, tmp);
 917         }
 918
 919         atomic_dec(&dev->refcnt);
 920 }
 921
 922 /**
 923  * Performs a ROM Search & registers any devices found.
 924  * The 1-wire search is a simple binary tree search.
 925  * For each bit of the address, we read two bits and write one bit.
 926  * The bit written will put to sleep all devies that don't match that bit.
 927  * When the two reads differ, the direction choice is obvious.
 928  * When both bits are 0, we must choose a path to take.
 929  * When we can scan all 64 bits without having to choose a path, we are done.
 930  *
 931  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 932  *
 933  * @dev        The master device to search
 934  * @cb         Function to call when a device is found
 935  */
 936 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 937 {
 938         u64 last_rn, rn, tmp64;
 939         int i, slave_count = 0;
 940         int last_zero, last_device;
 941         int search_bit, desc_bit;
 942         u8  triplet_ret = 0;
 943
 944         search_bit = 0;
 945         rn = dev->search_id;
 946         last_rn = 0;
 947         last_device = 0;
 948         last_zero = -1;
 949
 950         desc_bit = 64;
 951
 952         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 953                 last_rn = rn;
 954                 rn = 0;
 955
 956                 /*
 957                  * Reset bus and all 1-wire device state machines
 958                  * so they can respond to our requests.
 959                  *
 960                  * Return 0 - device(s) present, 1 - no devices present.
 961                  */
 962                 mutex_lock(&dev->bus_mutex);
 963                 if (w1_reset_bus(dev)) {
 964                         mutex_unlock(&dev->bus_mutex);
 965                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 966                         break;
 967                 }
 968
 969                 /* Do fast search on single slave bus */
 970                 if (dev->max_slave_count == 1) {
 971                         int rv;
 972                         w1_write_8(dev, W1_READ_ROM);
 973                         rv = w1_read_block(dev, (u8 *)&rn, 8);
 974                         mutex_unlock(&dev->bus_mutex);
 975
 976                         if (rv == 8 && rn)
 977                                 cb(dev, rn);
 978
 979                         break;
 980                 }
 981
 982                 /* Start the search */
 983                 w1_write_8(dev, search_type);
 984                 for (i = 0; i < 64; ++i) {
 985                         /* Determine the direction/search bit */
 986                         if (i == desc_bit)
 987                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 988                         else if (i > desc_bit)
 989                                 search_bit = 0;   /* take the 0 path on the next branch */
 990                         else
 991                                 search_bit = ((last_rn >> i) & 0x1);
 992
 993                         /** Read two bits and write one bit */
 994                         triplet_ret = w1_triplet(dev, search_bit);
 995
 996                         /* quit if no device responded */
 997                         if ( (triplet_ret & 0x03) == 0x03 )
 998                                 break;
 999
1000                         /* If both directions were valid, and we took the 0 path... */
1001                         if (triplet_ret == 0)
1002                                 last_zero = i;
1003
1004                         /* extract the direction taken & update the device number */
1005                         tmp64 = (triplet_ret >> 2);
1006                         rn |= (tmp64 << i);
1007
1008                         if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
1009                                 mutex_unlock(&dev->bus_mutex);
1010                                 dev_dbg(&dev->dev, "Abort w1_search\n");
1011                                 return;
1012                         }
1013                 }
1014                 mutex_unlock(&dev->bus_mutex);
1015
1016                 if ( (triplet_ret & 0x03) != 0x03 ) {
1017                         if ((desc_bit == last_zero) || (last_zero < 0)) {
1018                                 last_device = 1;
1019                                 dev->search_id = 0;
1020                         } else {
1021                                 dev->search_id = rn;
1022                         }
1023                         desc_bit = last_zero;
1024                         cb(dev, rn);
1025                 }
1026
1027                 if (!last_device && slave_count == dev->max_slave_count &&
1028                         !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
1029                         /* Only max_slave_count will be scanned in a search,
1030                          * but it will start where it left off next search
1031                          * until all ids are identified and then it will start
1032                          * over.  A continued search will report the previous
1033                          * last id as the first id (provided it is still on the
1034                          * bus).
1035                          */
1036                         dev_info(&dev->dev, "%s: max_slave_count %d reached, "
1037                                 "will continue next search.\n", __func__,
1038                                 dev->max_slave_count);
1039                         set_bit(W1_WARN_MAX_COUNT, &dev->flags);
1040                 }
1041         }
1042 }
1043
1044 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
1045         w1_slave_found_callback cb)
1046 {
1047         struct w1_slave *sl, *sln;
1048
1049         mutex_lock(&dev->list_mutex);
1050         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
1051                 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
1052         mutex_unlock(&dev->list_mutex);
1053
1054         w1_search_devices(dev, search_type, cb);
1055
1056         mutex_lock(&dev->list_mutex);
1057         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
1058                 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
1059                         mutex_unlock(&dev->list_mutex);
1060                         w1_slave_detach(sl);
1061                         mutex_lock(&dev->list_mutex);
1062                 }
1063                 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
1064                         sl->ttl = dev->slave_ttl;
1065         }
1066         mutex_unlock(&dev->list_mutex);
1067
1068         if (dev->search_count > 0)
1069                 dev->search_count--;
1070 }
1071
1072 static void w1_search_process(struct w1_master *dev, u8 search_type)
1073 {
1074         w1_search_process_cb(dev, search_type, w1_slave_found);
1075 }
1076
1077 int w1_process_callbacks(struct w1_master *dev)
1078 {
1079         int ret = 0;
1080         struct w1_async_cmd *async_cmd, *async_n;
1081
1082         /* The list can be added to in another thread, loop until it is empty */
1083         while (!list_empty(&dev->async_list)) {
1084                 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
1085                         async_entry) {
1086                         /* drop the lock, if it is a search it can take a long
1087                          * time */
1088                         mutex_unlock(&dev->list_mutex);
1089                         async_cmd->cb(dev, async_cmd);
1090                         ret = 1;
1091                         mutex_lock(&dev->list_mutex);
1092                 }
1093         }
1094         return ret;
1095 }
1096
1097 int w1_process(void *data)
1098 {
1099         struct w1_master *dev = (struct w1_master *) data;
1100         /* As long as w1_timeout is only set by a module parameter the sleep
1101          * time can be calculated in jiffies once.
1102          */
1103         const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
1104         /* remainder if it woke up early */
1105         unsigned long jremain = 0;
1106
1107         for (;;) {
1108
1109                 if (!jremain && dev->search_count) {
1110                         mutex_lock(&dev->mutex);
1111                         w1_search_process(dev, W1_SEARCH);
1112                         mutex_unlock(&dev->mutex);
1113                 }
1114
1115                 mutex_lock(&dev->list_mutex);
1116                 /* Note, w1_process_callback drops the lock while processing,
1117                  * but locks it again before returning.
1118                  */
1119                 if (!w1_process_callbacks(dev) && jremain) {
1120                         /* a wake up is either to stop the thread, process
1121                          * callbacks, or search, it isn't process callbacks, so
1122                          * schedule a search.
1123                          */
1124                         jremain = 1;
1125                 }
1126
1127                 try_to_freeze();
1128                 __set_current_state(TASK_INTERRUPTIBLE);
1129
1130                 /* hold list_mutex until after interruptible to prevent loosing
1131                  * the wakeup signal when async_cmd is added.
1132                  */
1133                 mutex_unlock(&dev->list_mutex);
1134
1135                 if (kthread_should_stop())
1136                         break;
1137
1138                 /* Only sleep when the search is active. */
1139                 if (dev->search_count) {
1140                         if (!jremain)
1141                                 jremain = jtime;
1142                         jremain = schedule_timeout(jremain);
1143                 }
1144                 else
1145                         schedule();
1146         }
1147
1148         atomic_dec(&dev->refcnt);
1149
1150         return 0;
1151 }
1152
1153 static int __init w1_init(void)
1154 {
1155         int retval;
1156
1157         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
1158
1159         w1_init_netlink();
1160
1161         retval = bus_register(&w1_bus_type);
1162         if (retval) {
1163                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
1164                 goto err_out_exit_init;
1165         }
1166
1167         retval = bus_register_notifier(&w1_bus_type, &w1_bus_nb);
1168         if (retval)
1169                 goto err_out_bus_unregister;
1170
1171         retval = driver_register(&w1_master_driver);
1172         if (retval) {
1173                 printk(KERN_ERR
1174                         "Failed to register master driver. err=%d.\n",
1175                         retval);
1176                 goto err_out_bus_unregister;
1177         }
1178
1179         retval = driver_register(&w1_slave_driver);
1180         if (retval) {
1181                 printk(KERN_ERR
1182                         "Failed to register slave driver. err=%d.\n",
1183                         retval);
1184                 goto err_out_master_unregister;
1185         }
1186
1187         return 0;
1188
1189 #if 0
1190 /* For undoing the slave register if there was a step after it. */
1191 err_out_slave_unregister:
1192         driver_unregister(&w1_slave_driver);
1193 #endif
1194
1195 err_out_master_unregister:
1196         driver_unregister(&w1_master_driver);
1197
1198 err_out_bus_unregister:
1199         bus_unregister(&w1_bus_type);
1200
1201 err_out_exit_init:
1202         return retval;
1203 }
1204
1205 static void __exit w1_fini(void)
1206 {
1207         struct w1_master *dev;
1208
1209         /* Set netlink removal messages and some cleanup */
1210         list_for_each_entry(dev, &w1_masters, w1_master_entry)
1211                 __w1_remove_master_device(dev);
1212
1213         w1_fini_netlink();
1214
1215         driver_unregister(&w1_slave_driver);
1216         driver_unregister(&w1_master_driver);
1217         bus_unregister(&w1_bus_type);
1218 }
1219
1220 module_init(w1_init);
1221 module_exit(w1_fini);