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         int ret;
 238
 239         ret = kstrtol(buf, 0, &tmp);
 240         if (ret)
 241                 return ret;
 242
 243         mutex_lock(&md->mutex);
 244         md->search_count = tmp;
 245         mutex_unlock(&md->mutex);
 246         wake_up_process(md->thread);
 247
 248         return count;
 249 }
 250
 251 static ssize_t w1_master_attribute_show_search(struct device *dev,
 252                                                struct device_attribute *attr,
 253                                                char *buf)
 254 {
 255         struct w1_master *md = dev_to_w1_master(dev);
 256         ssize_t count;
 257
 258         mutex_lock(&md->mutex);
 259         count = sprintf(buf, "%d\n", md->search_count);
 260         mutex_unlock(&md->mutex);
 261
 262         return count;
 263 }
 264
 265 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
 266                                                 struct device_attribute *attr,
 267                                                 const char *buf, size_t count)
 268 {
 269         long tmp;
 270         struct w1_master *md = dev_to_w1_master(dev);
 271         int ret;
 272
 273         ret = kstrtol(buf, 0, &tmp);
 274         if (ret)
 275                 return ret;
 276
 277         mutex_lock(&md->mutex);
 278         md->enable_pullup = tmp;
 279         mutex_unlock(&md->mutex);
 280         wake_up_process(md->thread);
 281
 282         return count;
 283 }
 284
 285 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
 286                                                struct device_attribute *attr,
 287                                                char *buf)
 288 {
 289         struct w1_master *md = dev_to_w1_master(dev);
 290         ssize_t count;
 291
 292         mutex_lock(&md->mutex);
 293         count = sprintf(buf, "%d\n", md->enable_pullup);
 294         mutex_unlock(&md->mutex);
 295
 296         return count;
 297 }
 298
 299 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 300 {
 301         struct w1_master *md = dev_to_w1_master(dev);
 302         ssize_t count;
 303
 304         mutex_lock(&md->mutex);
 305         count = sprintf(buf, "0x%p\n", md->bus_master);
 306         mutex_unlock(&md->mutex);
 307         return count;
 308 }
 309
 310 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 311 {
 312         ssize_t count;
 313         count = sprintf(buf, "%d\n", w1_timeout);
 314         return count;
 315 }
 316
 317 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 318 {
 319         struct w1_master *md = dev_to_w1_master(dev);
 320         ssize_t count;
 321
 322         mutex_lock(&md->mutex);
 323         count = sprintf(buf, "%d\n", md->max_slave_count);
 324         mutex_unlock(&md->mutex);
 325         return count;
 326 }
 327
 328 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 329 {
 330         struct w1_master *md = dev_to_w1_master(dev);
 331         ssize_t count;
 332
 333         mutex_lock(&md->mutex);
 334         count = sprintf(buf, "%lu\n", md->attempts);
 335         mutex_unlock(&md->mutex);
 336         return count;
 337 }
 338
 339 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 340 {
 341         struct w1_master *md = dev_to_w1_master(dev);
 342         ssize_t count;
 343
 344         mutex_lock(&md->mutex);
 345         count = sprintf(buf, "%d\n", md->slave_count);
 346         mutex_unlock(&md->mutex);
 347         return count;
 348 }
 349
 350 static ssize_t w1_master_attribute_show_slaves(struct device *dev,
 351         struct device_attribute *attr, char *buf)
 352 {
 353         struct w1_master *md = dev_to_w1_master(dev);
 354         int c = PAGE_SIZE;
 355
 356         mutex_lock(&md->mutex);
 357
 358         if (md->slave_count == 0)
 359                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 360         else {
 361                 struct list_head *ent, *n;
 362                 struct w1_slave *sl;
 363
 364                 list_for_each_safe(ent, n, &md->slist) {
 365                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 366
 367                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 368                 }
 369         }
 370
 371         mutex_unlock(&md->mutex);
 372
 373         return PAGE_SIZE - c;
 374 }
 375
 376 static ssize_t w1_master_attribute_show_add(struct device *dev,
 377         struct device_attribute *attr, char *buf)
 378 {
 379         int c = PAGE_SIZE;
 380         c -= snprintf(buf+PAGE_SIZE - c, c,
 381                 "write device id xx-xxxxxxxxxxxx to add slave\n");
 382         return PAGE_SIZE - c;
 383 }
 384
 385 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
 386         struct w1_reg_num *rn)
 387 {
 388         unsigned int family;
 389         unsigned long long id;
 390         int i;
 391         u64 rn64_le;
 392
 393         /* The CRC value isn't read from the user because the sysfs directory
 394          * doesn't include it and most messages from the bus search don't
 395          * print it either.  It would be unreasonable for the user to then
 396          * provide it.
 397          */
 398         const char *error_msg = "bad slave string format, expecting "
 399                 "ff-dddddddddddd\n";
 400
 401         if (buf[2] != '-') {
 402                 dev_err(dev, "%s", error_msg);
 403                 return -EINVAL;
 404         }
 405         i = sscanf(buf, "%02x-%012llx", &family, &id);
 406         if (i != 2) {
 407                 dev_err(dev, "%s", error_msg);
 408                 return -EINVAL;
 409         }
 410         rn->family = family;
 411         rn->id = id;
 412
 413         rn64_le = cpu_to_le64(*(u64 *)rn);
 414         rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
 415
 416 #if 0
 417         dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
 418                   rn->family, (unsigned long long)rn->id, rn->crc);
 419 #endif
 420
 421         return 0;
 422 }
 423
 424 /* Searches the slaves in the w1_master and returns a pointer or NULL.
 425  * Note: must hold the mutex
 426  */
 427 static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
 428         struct w1_reg_num *rn)
 429 {
 430         struct w1_slave *sl;
 431         list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 432                 if (sl->reg_num.family == rn->family &&
 433                                 sl->reg_num.id == rn->id &&
 434                                 sl->reg_num.crc == rn->crc) {
 435                         return sl;
 436                 }
 437         }
 438         return NULL;
 439 }
 440
 441 static ssize_t w1_master_attribute_store_add(struct device *dev,
 442                                                 struct device_attribute *attr,
 443                                                 const char *buf, size_t count)
 444 {
 445         struct w1_master *md = dev_to_w1_master(dev);
 446         struct w1_reg_num rn;
 447         struct w1_slave *sl;
 448         ssize_t result = count;
 449
 450         if (w1_atoreg_num(dev, buf, count, &rn))
 451                 return -EINVAL;
 452
 453         mutex_lock(&md->mutex);
 454         sl = w1_slave_search_device(md, &rn);
 455         /* It would be nice to do a targeted search one the one-wire bus
 456          * for the new device to see if it is out there or not.  But the
 457          * current search doesn't support that.
 458          */
 459         if (sl) {
 460                 dev_info(dev, "Device %s already exists\n", sl->name);
 461                 result = -EINVAL;
 462         } else {
 463                 w1_attach_slave_device(md, &rn);
 464         }
 465         mutex_unlock(&md->mutex);
 466
 467         return result;
 468 }
 469
 470 static ssize_t w1_master_attribute_show_remove(struct device *dev,
 471         struct device_attribute *attr, char *buf)
 472 {
 473         int c = PAGE_SIZE;
 474         c -= snprintf(buf+PAGE_SIZE - c, c,
 475                 "write device id xx-xxxxxxxxxxxx to remove slave\n");
 476         return PAGE_SIZE - c;
 477 }
 478
 479 static ssize_t w1_master_attribute_store_remove(struct device *dev,
 480                                                 struct device_attribute *attr,
 481                                                 const char *buf, size_t count)
 482 {
 483         struct w1_master *md = dev_to_w1_master(dev);
 484         struct w1_reg_num rn;
 485         struct w1_slave *sl;
 486         ssize_t result = count;
 487
 488         if (w1_atoreg_num(dev, buf, count, &rn))
 489                 return -EINVAL;
 490
 491         mutex_lock(&md->mutex);
 492         sl = w1_slave_search_device(md, &rn);
 493         if (sl) {
 494                 w1_slave_detach(sl);
 495         } else {
 496                 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
 497                         (unsigned long long)rn.id);
 498                 result = -EINVAL;
 499         }
 500         mutex_unlock(&md->mutex);
 501
 502         return result;
 503 }
 504
 505 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 506         struct device_attribute w1_master_attribute_##_name =   \
 507                 __ATTR(w1_master_##_name, _mode,                \
 508                        w1_master_attribute_show_##_name, NULL)
 509
 510 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 511         struct device_attribute w1_master_attribute_##_name =   \
 512                 __ATTR(w1_master_##_name, _mode,                \
 513                        w1_master_attribute_show_##_name,        \
 514                        w1_master_attribute_store_##_name)
 515
 516 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 517 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 518 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 519 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 520 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 521 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 522 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 523 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
 524 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
 525 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
 526 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
 527
 528 static struct attribute *w1_master_default_attrs[] = {
 529         &w1_master_attribute_name.attr,
 530         &w1_master_attribute_slaves.attr,
 531         &w1_master_attribute_slave_count.attr,
 532         &w1_master_attribute_max_slave_count.attr,
 533         &w1_master_attribute_attempts.attr,
 534         &w1_master_attribute_timeout.attr,
 535         &w1_master_attribute_pointer.attr,
 536         &w1_master_attribute_search.attr,
 537         &w1_master_attribute_pullup.attr,
 538         &w1_master_attribute_add.attr,
 539         &w1_master_attribute_remove.attr,
 540         NULL
 541 };
 542
 543 static struct attribute_group w1_master_defattr_group = {
 544         .attrs = w1_master_default_attrs,
 545 };
 546
 547 int w1_create_master_attributes(struct w1_master *master)
 548 {
 549         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 550 }
 551
 552 void w1_destroy_master_attributes(struct w1_master *master)
 553 {
 554         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 555 }
 556
 557 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 558 {
 559         struct w1_master *md = NULL;
 560         struct w1_slave *sl = NULL;
 561         char *event_owner, *name;
 562         int err = 0;
 563
 564         if (dev->driver == &w1_master_driver) {
 565                 md = container_of(dev, struct w1_master, dev);
 566                 event_owner = "master";
 567                 name = md->name;
 568         } else if (dev->driver == &w1_slave_driver) {
 569                 sl = container_of(dev, struct w1_slave, dev);
 570                 event_owner = "slave";
 571                 name = sl->name;
 572         } else {
 573                 dev_dbg(dev, "Unknown event.\n");
 574                 return -EINVAL;
 575         }
 576
 577         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 578                         event_owner, name, dev_name(dev));
 579
 580         if (dev->driver != &w1_slave_driver || !sl)
 581                 goto end;
 582
 583         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 584         if (err)
 585                 goto end;
 586
 587         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 588                              (unsigned long long)sl->reg_num.id);
 589 end:
 590         return err;
 591 }
 592
 593 /*
 594  * Handle sysfs file creation and removal here, before userspace is told that
 595  * the device is added / removed from the system
 596  */
 597 static int w1_bus_notify(struct notifier_block *nb, unsigned long action,
 598                          void *data)
 599 {
 600         struct device *dev = data;
 601         struct w1_slave *sl;
 602         struct w1_family_ops *fops;
 603         int err;
 604
 605         /*
 606          * Only care about slave devices at the moment.  Yes, we should use a
 607          * separate "type" for this, but for now, look at the release function
 608          * to know which type it is...
 609          */
 610         if (dev->release != w1_slave_release)
 611                 return 0;
 612
 613         sl = dev_to_w1_slave(dev);
 614         fops = sl->family->fops;
 615
 616         if (!fops)
 617                 return 0;
 618
 619         switch (action) {
 620         case BUS_NOTIFY_ADD_DEVICE:
 621                 /* if the family driver needs to initialize something... */
 622                 if (fops->add_slave) {
 623                         err = fops->add_slave(sl);
 624                         if (err < 0) {
 625                                 dev_err(&sl->dev,
 626                                         "add_slave() call failed. err=%d\n",
 627                                         err);
 628                                 return err;
 629                         }
 630                 }
 631                 if (fops->groups) {
 632                         err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
 633                         if (err) {
 634                                 dev_err(&sl->dev,
 635                                         "sysfs group creation failed. err=%d\n",
 636                                         err);
 637                                 return err;
 638                         }
 639                 }
 640
 641                 break;
 642         case BUS_NOTIFY_DEL_DEVICE:
 643                 if (fops->remove_slave)
 644                         sl->family->fops->remove_slave(sl);
 645                 if (fops->groups)
 646                         sysfs_remove_groups(&sl->dev.kobj, fops->groups);
 647                 break;
 648         }
 649         return 0;
 650 }
 651
 652 static struct notifier_block w1_bus_nb = {
 653         .notifier_call = w1_bus_notify,
 654 };
 655
 656 static int __w1_attach_slave_device(struct w1_slave *sl)
 657 {
 658         int err;
 659
 660         sl->dev.parent = &sl->master->dev;
 661         sl->dev.driver = &w1_slave_driver;
 662         sl->dev.bus = &w1_bus_type;
 663         sl->dev.release = &w1_slave_release;
 664         sl->dev.groups = w1_slave_groups;
 665
 666         dev_set_name(&sl->dev, "%02x-%012llx",
 667                  (unsigned int) sl->reg_num.family,
 668                  (unsigned long long) sl->reg_num.id);
 669         snprintf(&sl->name[0], sizeof(sl->name),
 670                  "%02x-%012llx",
 671                  (unsigned int) sl->reg_num.family,
 672                  (unsigned long long) sl->reg_num.id);
 673
 674         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 675                 dev_name(&sl->dev), sl);
 676
 677         err = device_register(&sl->dev);
 678         if (err < 0) {
 679                 dev_err(&sl->dev,
 680                         "Device registration [%s] failed. err=%d\n",
 681                         dev_name(&sl->dev), err);
 682                 return err;
 683         }
 684
 685
 686         dev_set_uevent_suppress(&sl->dev, false);
 687         kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
 688
 689         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 690
 691         return 0;
 692 }
 693
 694 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 695 {
 696         struct w1_slave *sl;
 697         struct w1_family *f;
 698         int err;
 699         struct w1_netlink_msg msg;
 700
 701         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 702         if (!sl) {
 703                 dev_err(&dev->dev,
 704                          "%s: failed to allocate new slave device.\n",
 705                          __func__);
 706                 return -ENOMEM;
 707         }
 708
 709
 710         sl->owner = THIS_MODULE;
 711         sl->master = dev;
 712         set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 713
 714         memset(&msg, 0, sizeof(msg));
 715         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 716         atomic_set(&sl->refcnt, 0);
 717         init_completion(&sl->released);
 718
 719         /* slave modules need to be loaded in a context with unlocked mutex */
 720         mutex_unlock(&dev->mutex);
 721         request_module("w1-family-0x%0x", rn->family);
 722         mutex_lock(&dev->mutex);
 723
 724         spin_lock(&w1_flock);
 725         f = w1_family_registered(rn->family);
 726         if (!f) {
 727                 f= &w1_default_family;
 728                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 729                           rn->family, rn->family,
 730                           (unsigned long long)rn->id, rn->crc);
 731         }
 732         __w1_family_get(f);
 733         spin_unlock(&w1_flock);
 734
 735         sl->family = f;
 736
 737
 738         err = __w1_attach_slave_device(sl);
 739         if (err < 0) {
 740                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 741                          sl->name);
 742                 w1_family_put(sl->family);
 743                 kfree(sl);
 744                 return err;
 745         }
 746
 747         sl->ttl = dev->slave_ttl;
 748         dev->slave_count++;
 749
 750         memcpy(msg.id.id, rn, sizeof(msg.id));
 751         msg.type = W1_SLAVE_ADD;
 752         w1_netlink_send(dev, &msg);
 753
 754         return 0;
 755 }
 756
 757 void w1_slave_detach(struct w1_slave *sl)
 758 {
 759         struct w1_netlink_msg msg;
 760
 761         dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 762
 763         list_del(&sl->w1_slave_entry);
 764
 765         memset(&msg, 0, sizeof(msg));
 766         memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 767         msg.type = W1_SLAVE_REMOVE;
 768         w1_netlink_send(sl->master, &msg);
 769
 770         device_unregister(&sl->dev);
 771
 772         wait_for_completion(&sl->released);
 773         kfree(sl);
 774 }
 775
 776 struct w1_master *w1_search_master_id(u32 id)
 777 {
 778         struct w1_master *dev;
 779         int found = 0;
 780
 781         mutex_lock(&w1_mlock);
 782         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 783                 if (dev->id == id) {
 784                         found = 1;
 785                         atomic_inc(&dev->refcnt);
 786                         break;
 787                 }
 788         }
 789         mutex_unlock(&w1_mlock);
 790
 791         return (found)?dev:NULL;
 792 }
 793
 794 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 795 {
 796         struct w1_master *dev;
 797         struct w1_slave *sl = NULL;
 798         int found = 0;
 799
 800         mutex_lock(&w1_mlock);
 801         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 802                 mutex_lock(&dev->mutex);
 803                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 804                         if (sl->reg_num.family == id->family &&
 805                                         sl->reg_num.id == id->id &&
 806                                         sl->reg_num.crc == id->crc) {
 807                                 found = 1;
 808                                 atomic_inc(&dev->refcnt);
 809                                 atomic_inc(&sl->refcnt);
 810                                 break;
 811                         }
 812                 }
 813                 mutex_unlock(&dev->mutex);
 814
 815                 if (found)
 816                         break;
 817         }
 818         mutex_unlock(&w1_mlock);
 819
 820         return (found)?sl:NULL;
 821 }
 822
 823 void w1_reconnect_slaves(struct w1_family *f, int attach)
 824 {
 825         struct w1_slave *sl, *sln;
 826         struct w1_master *dev;
 827
 828         mutex_lock(&w1_mlock);
 829         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 830                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 831                         "for family %02x.\n", dev->name, f->fid);
 832                 mutex_lock(&dev->mutex);
 833                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 834                         /* If it is a new family, slaves with the default
 835                          * family driver and are that family will be
 836                          * connected.  If the family is going away, devices
 837                          * matching that family are reconneced.
 838                          */
 839                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 840                                 && sl->reg_num.family == f->fid) ||
 841                                 (!attach && sl->family->fid == f->fid)) {
 842                                 struct w1_reg_num rn;
 843
 844                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 845                                 w1_slave_detach(sl);
 846
 847                                 w1_attach_slave_device(dev, &rn);
 848                         }
 849                 }
 850                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 851                         "has been finished.\n", dev->name);
 852                 mutex_unlock(&dev->mutex);
 853         }
 854         mutex_unlock(&w1_mlock);
 855 }
 856
 857 void w1_slave_found(struct w1_master *dev, u64 rn)
 858 {
 859         struct w1_slave *sl;
 860         struct w1_reg_num *tmp;
 861         u64 rn_le = cpu_to_le64(rn);
 862
 863         atomic_inc(&dev->refcnt);
 864
 865         tmp = (struct w1_reg_num *) &rn;
 866
 867         sl = w1_slave_search_device(dev, tmp);
 868         if (sl) {
 869                 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 870         } else {
 871                 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
 872                         w1_attach_slave_device(dev, tmp);
 873         }
 874
 875         atomic_dec(&dev->refcnt);
 876 }
 877
 878 /**
 879  * Performs a ROM Search & registers any devices found.
 880  * The 1-wire search is a simple binary tree search.
 881  * For each bit of the address, we read two bits and write one bit.
 882  * The bit written will put to sleep all devies that don't match that bit.
 883  * When the two reads differ, the direction choice is obvious.
 884  * When both bits are 0, we must choose a path to take.
 885  * When we can scan all 64 bits without having to choose a path, we are done.
 886  *
 887  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 888  *
 889  * @dev        The master device to search
 890  * @cb         Function to call when a device is found
 891  */
 892 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 893 {
 894         u64 last_rn, rn, tmp64;
 895         int i, slave_count = 0;
 896         int last_zero, last_device;
 897         int search_bit, desc_bit;
 898         u8  triplet_ret = 0;
 899
 900         search_bit = 0;
 901         rn = last_rn = 0;
 902         last_device = 0;
 903         last_zero = -1;
 904
 905         desc_bit = 64;
 906
 907         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 908                 last_rn = rn;
 909                 rn = 0;
 910
 911                 /*
 912                  * Reset bus and all 1-wire device state machines
 913                  * so they can respond to our requests.
 914                  *
 915                  * Return 0 - device(s) present, 1 - no devices present.
 916                  */
 917                 mutex_lock(&dev->bus_mutex);
 918                 if (w1_reset_bus(dev)) {
 919                         mutex_unlock(&dev->bus_mutex);
 920                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 921                         break;
 922                 }
 923
 924                 /* Do fast search on single slave bus */
 925                 if (dev->max_slave_count == 1) {
 926                         int rv;
 927                         w1_write_8(dev, W1_READ_ROM);
 928                         rv = w1_read_block(dev, (u8 *)&rn, 8);
 929                         mutex_unlock(&dev->bus_mutex);
 930
 931                         if (rv == 8 && rn)
 932                                 cb(dev, rn);
 933
 934                         break;
 935                 }
 936
 937                 /* Start the search */
 938                 w1_write_8(dev, search_type);
 939                 for (i = 0; i < 64; ++i) {
 940                         /* Determine the direction/search bit */
 941                         if (i == desc_bit)
 942                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 943                         else if (i > desc_bit)
 944                                 search_bit = 0;   /* take the 0 path on the next branch */
 945                         else
 946                                 search_bit = ((last_rn >> i) & 0x1);
 947
 948                         /** Read two bits and write one bit */
 949                         triplet_ret = w1_triplet(dev, search_bit);
 950
 951                         /* quit if no device responded */
 952                         if ( (triplet_ret & 0x03) == 0x03 )
 953                                 break;
 954
 955                         /* If both directions were valid, and we took the 0 path... */
 956                         if (triplet_ret == 0)
 957                                 last_zero = i;
 958
 959                         /* extract the direction taken & update the device number */
 960                         tmp64 = (triplet_ret >> 2);
 961                         rn |= (tmp64 << i);
 962
 963                         /* ensure we're called from kthread and not by netlink callback */
 964                         if (!dev->priv && kthread_should_stop()) {
 965                                 mutex_unlock(&dev->bus_mutex);
 966                                 dev_dbg(&dev->dev, "Abort w1_search\n");
 967                                 return;
 968                         }
 969                 }
 970                 mutex_unlock(&dev->bus_mutex);
 971
 972                 if ( (triplet_ret & 0x03) != 0x03 ) {
 973                         if ( (desc_bit == last_zero) || (last_zero < 0))
 974                                 last_device = 1;
 975                         desc_bit = last_zero;
 976                         cb(dev, rn);
 977                 }
 978         }
 979 }
 980
 981 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
 982         w1_slave_found_callback cb)
 983 {
 984         struct w1_slave *sl, *sln;
 985
 986         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 987                 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
 988
 989         w1_search_devices(dev, search_type, cb);
 990
 991         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 992                 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl)
 993                         w1_slave_detach(sl);
 994                 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
 995                         sl->ttl = dev->slave_ttl;
 996         }
 997
 998         if (dev->search_count > 0)
 999                 dev->search_count--;
1000 }
1001
1002 static void w1_search_process(struct w1_master *dev, u8 search_type)
1003 {
1004         w1_search_process_cb(dev, search_type, w1_slave_found);
1005 }
1006
1007 int w1_process(void *data)
1008 {
1009         struct w1_master *dev = (struct w1_master *) data;
1010         /* As long as w1_timeout is only set by a module parameter the sleep
1011          * time can be calculated in jiffies once.
1012          */
1013         const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
1014
1015         while (!kthread_should_stop()) {
1016                 if (dev->search_count) {
1017                         mutex_lock(&dev->mutex);
1018                         w1_search_process(dev, W1_SEARCH);
1019                         mutex_unlock(&dev->mutex);
1020                 }
1021
1022                 try_to_freeze();
1023                 __set_current_state(TASK_INTERRUPTIBLE);
1024
1025                 if (kthread_should_stop())
1026                         break;
1027
1028                 /* Only sleep when the search is active. */
1029                 if (dev->search_count)
1030                         schedule_timeout(jtime);
1031                 else
1032                         schedule();
1033         }
1034
1035         atomic_dec(&dev->refcnt);
1036
1037         return 0;
1038 }
1039
1040 static int __init w1_init(void)
1041 {
1042         int retval;
1043
1044         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
1045
1046         w1_init_netlink();
1047
1048         retval = bus_register(&w1_bus_type);
1049         if (retval) {
1050                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
1051                 goto err_out_exit_init;
1052         }
1053
1054         retval = bus_register_notifier(&w1_bus_type, &w1_bus_nb);
1055         if (retval)
1056                 goto err_out_bus_unregister;
1057
1058         retval = driver_register(&w1_master_driver);
1059         if (retval) {
1060                 printk(KERN_ERR
1061                         "Failed to register master driver. err=%d.\n",
1062                         retval);
1063                 goto err_out_bus_unregister;
1064         }
1065
1066         retval = driver_register(&w1_slave_driver);
1067         if (retval) {
1068                 printk(KERN_ERR
1069                         "Failed to register slave driver. err=%d.\n",
1070                         retval);
1071                 goto err_out_master_unregister;
1072         }
1073
1074         return 0;
1075
1076 #if 0
1077 /* For undoing the slave register if there was a step after it. */
1078 err_out_slave_unregister:
1079         driver_unregister(&w1_slave_driver);
1080 #endif
1081
1082 err_out_master_unregister:
1083         driver_unregister(&w1_master_driver);
1084
1085 err_out_bus_unregister:
1086         bus_unregister(&w1_bus_type);
1087
1088 err_out_exit_init:
1089         return retval;
1090 }
1091
1092 static void __exit w1_fini(void)
1093 {
1094         struct w1_master *dev;
1095
1096         /* Set netlink removal messages and some cleanup */
1097         list_for_each_entry(dev, &w1_masters, w1_master_entry)
1098                 __w1_remove_master_device(dev);
1099
1100         w1_fini_netlink();
1101
1102         driver_unregister(&w1_slave_driver);
1103         driver_unregister(&w1_master_driver);
1104         bus_unregister(&w1_bus_type);
1105 }
1106
1107 module_init(w1_init);
1108 module_exit(w1_fini);