drivers/w1/w1.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
   4  */
   5
   6 #include <linux/delay.h>
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/moduleparam.h>
  10 #include <linux/list.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/timer.h>
  14 #include <linux/device.h>
  15 #include <linux/slab.h>
  16 #include <linux/sched.h>
  17 #include <linux/kthread.h>
  18 #include <linux/freezer.h>
  19 #include <linux/hwmon.h>
  20 #include <linux/of.h>
  21
  22 #include <linux/atomic.h>
  23
  24 #include "w1_internal.h"
  25 #include "w1_netlink.h"
  26
  27 #define W1_FAMILY_DEFAULT       0
  28 #define W1_FAMILY_DS28E04       0x1C /* for crc quirk */
  29
  30
  31 static int w1_timeout = 10;
  32 module_param_named(timeout, w1_timeout, int, 0);
  33 MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
  34
  35 static int w1_timeout_us = 0;
  36 module_param_named(timeout_us, w1_timeout_us, int, 0);
  37 MODULE_PARM_DESC(timeout_us,
  38                  "time in microseconds between automatic slave searches");
  39
  40 /* A search stops when w1_max_slave_count devices have been found in that
  41  * search.  The next search will start over and detect the same set of devices
  42  * on a static 1-wire bus.  Memory is not allocated based on this number, just
  43  * on the number of devices known to the kernel.  Having a high number does not
  44  * consume additional resources.  As a special case, if there is only one
  45  * device on the network and w1_max_slave_count is set to 1, the device id can
  46  * be read directly skipping the normal slower search process.
  47  */
  48 int w1_max_slave_count = 64;
  49 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  50 MODULE_PARM_DESC(max_slave_count,
  51         "maximum number of slaves detected in a search");
  52
  53 int w1_max_slave_ttl = 10;
  54 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  55 MODULE_PARM_DESC(slave_ttl,
  56         "Number of searches not seeing a slave before it will be removed");
  57
  58 DEFINE_MUTEX(w1_mlock);
  59 LIST_HEAD(w1_masters);
  60
  61 static int w1_master_probe(struct device *dev)
  62 {
  63         return -ENODEV;
  64 }
  65
  66 static void w1_master_release(struct device *dev)
  67 {
  68         struct w1_master *md = dev_to_w1_master(dev);
  69
  70         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  71         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  72         kfree(md);
  73 }
  74
  75 static void w1_slave_release(struct device *dev)
  76 {
  77         struct w1_slave *sl = dev_to_w1_slave(dev);
  78
  79         dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);
  80
  81         w1_family_put(sl->family);
  82         sl->master->slave_count--;
  83 }
  84
  85 static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
  86 {
  87         struct w1_slave *sl = dev_to_w1_slave(dev);
  88
  89         return sprintf(buf, "%s\n", sl->name);
  90 }
  91 static DEVICE_ATTR_RO(name);
  92
  93 static ssize_t id_show(struct device *dev,
  94         struct device_attribute *attr, char *buf)
  95 {
  96         struct w1_slave *sl = dev_to_w1_slave(dev);
  97         ssize_t count = sizeof(sl->reg_num);
  98
  99         memcpy(buf, (u8 *)&sl->reg_num, count);
 100         return count;
 101 }
 102 static DEVICE_ATTR_RO(id);
 103
 104 static struct attribute *w1_slave_attrs[] = {
 105         &dev_attr_name.attr,
 106         &dev_attr_id.attr,
 107         NULL,
 108 };
 109 ATTRIBUTE_GROUPS(w1_slave);
 110
 111 /* Default family */
 112
 113 static ssize_t rw_write(struct file *filp, struct kobject *kobj,
 114                         struct bin_attribute *bin_attr, char *buf, loff_t off,
 115                         size_t count)
 116 {
 117         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 118
 119         mutex_lock(&sl->master->mutex);
 120         if (w1_reset_select_slave(sl)) {
 121                 count = 0;
 122                 goto out_up;
 123         }
 124
 125         w1_write_block(sl->master, buf, count);
 126
 127 out_up:
 128         mutex_unlock(&sl->master->mutex);
 129         return count;
 130 }
 131
 132 static ssize_t rw_read(struct file *filp, struct kobject *kobj,
 133                        struct bin_attribute *bin_attr, char *buf, loff_t off,
 134                        size_t count)
 135 {
 136         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 137
 138         mutex_lock(&sl->master->mutex);
 139         w1_read_block(sl->master, buf, count);
 140         mutex_unlock(&sl->master->mutex);
 141         return count;
 142 }
 143
 144 static BIN_ATTR_RW(rw, PAGE_SIZE);
 145
 146 static struct bin_attribute *w1_slave_bin_attrs[] = {
 147         &bin_attr_rw,
 148         NULL,
 149 };
 150
 151 static const struct attribute_group w1_slave_default_group = {
 152         .bin_attrs = w1_slave_bin_attrs,
 153 };
 154
 155 static const struct attribute_group *w1_slave_default_groups[] = {
 156         &w1_slave_default_group,
 157         NULL,
 158 };
 159
 160 static const struct w1_family_ops w1_default_fops = {
 161         .groups         = w1_slave_default_groups,
 162 };
 163
 164 static struct w1_family w1_default_family = {
 165         .fops = &w1_default_fops,
 166 };
 167
 168 static int w1_uevent(const struct device *dev, struct kobj_uevent_env *env);
 169
 170 static struct bus_type w1_bus_type = {
 171         .name = "w1",
 172         .uevent = w1_uevent,
 173 };
 174
 175 struct device_driver w1_master_driver = {
 176         .name = "w1_master_driver",
 177         .bus = &w1_bus_type,
 178         .probe = w1_master_probe,
 179 };
 180
 181 struct device w1_master_device = {
 182         .parent = NULL,
 183         .bus = &w1_bus_type,
 184         .init_name = "w1 bus master",
 185         .driver = &w1_master_driver,
 186         .release = &w1_master_release
 187 };
 188
 189 static struct device_driver w1_slave_driver = {
 190         .name = "w1_slave_driver",
 191         .bus = &w1_bus_type,
 192 };
 193
 194 #if 0
 195 struct device w1_slave_device = {
 196         .parent = NULL,
 197         .bus = &w1_bus_type,
 198         .init_name = "w1 bus slave",
 199         .driver = &w1_slave_driver,
 200         .release = &w1_slave_release
 201 };
 202 #endif  /*  0  */
 203
 204 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 205 {
 206         struct w1_master *md = dev_to_w1_master(dev);
 207         ssize_t count;
 208
 209         mutex_lock(&md->mutex);
 210         count = sprintf(buf, "%s\n", md->name);
 211         mutex_unlock(&md->mutex);
 212
 213         return count;
 214 }
 215
 216 static ssize_t w1_master_attribute_store_search(struct device * dev,
 217                                                 struct device_attribute *attr,
 218                                                 const char * buf, size_t count)
 219 {
 220         long tmp;
 221         struct w1_master *md = dev_to_w1_master(dev);
 222         int ret;
 223
 224         ret = kstrtol(buf, 0, &tmp);
 225         if (ret)
 226                 return ret;
 227
 228         mutex_lock(&md->mutex);
 229         md->search_count = tmp;
 230         mutex_unlock(&md->mutex);
 231         /* Only wake if it is going to be searching. */
 232         if (tmp)
 233                 wake_up_process(md->thread);
 234
 235         return count;
 236 }
 237
 238 static ssize_t w1_master_attribute_show_search(struct device *dev,
 239                                                struct device_attribute *attr,
 240                                                char *buf)
 241 {
 242         struct w1_master *md = dev_to_w1_master(dev);
 243         ssize_t count;
 244
 245         mutex_lock(&md->mutex);
 246         count = sprintf(buf, "%d\n", md->search_count);
 247         mutex_unlock(&md->mutex);
 248
 249         return count;
 250 }
 251
 252 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
 253                                                 struct device_attribute *attr,
 254                                                 const char *buf, size_t count)
 255 {
 256         long tmp;
 257         struct w1_master *md = dev_to_w1_master(dev);
 258         int ret;
 259
 260         ret = kstrtol(buf, 0, &tmp);
 261         if (ret)
 262                 return ret;
 263
 264         mutex_lock(&md->mutex);
 265         md->enable_pullup = tmp;
 266         mutex_unlock(&md->mutex);
 267
 268         return count;
 269 }
 270
 271 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
 272                                                struct device_attribute *attr,
 273                                                char *buf)
 274 {
 275         struct w1_master *md = dev_to_w1_master(dev);
 276         ssize_t count;
 277
 278         mutex_lock(&md->mutex);
 279         count = sprintf(buf, "%d\n", md->enable_pullup);
 280         mutex_unlock(&md->mutex);
 281
 282         return count;
 283 }
 284
 285 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 286 {
 287         struct w1_master *md = dev_to_w1_master(dev);
 288         ssize_t count;
 289
 290         mutex_lock(&md->mutex);
 291         count = sprintf(buf, "0x%p\n", md->bus_master);
 292         mutex_unlock(&md->mutex);
 293         return count;
 294 }
 295
 296 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 297 {
 298         return sprintf(buf, "%d\n", w1_timeout);
 299 }
 300
 301 static ssize_t w1_master_attribute_show_timeout_us(struct device *dev,
 302         struct device_attribute *attr, char *buf)
 303 {
 304         return sprintf(buf, "%d\n", w1_timeout_us);
 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         int tmp;
 311         struct w1_master *md = dev_to_w1_master(dev);
 312
 313         if (kstrtoint(buf, 0, &tmp) || 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(timeout_us, S_IRUGO);
 534 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 535 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
 536 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
 537 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
 538 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
 539
 540 static struct attribute *w1_master_default_attrs[] = {
 541         &w1_master_attribute_name.attr,
 542         &w1_master_attribute_slaves.attr,
 543         &w1_master_attribute_slave_count.attr,
 544         &w1_master_attribute_max_slave_count.attr,
 545         &w1_master_attribute_attempts.attr,
 546         &w1_master_attribute_timeout.attr,
 547         &w1_master_attribute_timeout_us.attr,
 548         &w1_master_attribute_pointer.attr,
 549         &w1_master_attribute_search.attr,
 550         &w1_master_attribute_pullup.attr,
 551         &w1_master_attribute_add.attr,
 552         &w1_master_attribute_remove.attr,
 553         NULL
 554 };
 555
 556 static const struct attribute_group w1_master_defattr_group = {
 557         .attrs = w1_master_default_attrs,
 558 };
 559
 560 int w1_create_master_attributes(struct w1_master *master)
 561 {
 562         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 563 }
 564
 565 void w1_destroy_master_attributes(struct w1_master *master)
 566 {
 567         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 568 }
 569
 570 static int w1_uevent(const struct device *dev, struct kobj_uevent_env *env)
 571 {
 572         const struct w1_master *md = NULL;
 573         const struct w1_slave *sl = NULL;
 574         const char *event_owner, *name;
 575         int err = 0;
 576
 577         if (dev->driver == &w1_master_driver) {
 578                 md = container_of(dev, struct w1_master, dev);
 579                 event_owner = "master";
 580                 name = md->name;
 581         } else if (dev->driver == &w1_slave_driver) {
 582                 sl = container_of(dev, struct w1_slave, dev);
 583                 event_owner = "slave";
 584                 name = sl->name;
 585         } else {
 586                 dev_dbg(dev, "Unknown event.\n");
 587                 return -EINVAL;
 588         }
 589
 590         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 591                         event_owner, name, dev_name(dev));
 592
 593         if (dev->driver != &w1_slave_driver || !sl)
 594                 goto end;
 595
 596         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 597         if (err)
 598                 goto end;
 599
 600         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 601                              (unsigned long long)sl->reg_num.id);
 602 end:
 603         return err;
 604 }
 605
 606 static int w1_family_notify(unsigned long action, struct w1_slave *sl)
 607 {
 608         const struct w1_family_ops *fops;
 609         int err;
 610
 611         fops = sl->family->fops;
 612
 613         if (!fops)
 614                 return 0;
 615
 616         switch (action) {
 617         case BUS_NOTIFY_ADD_DEVICE:
 618                 /* if the family driver needs to initialize something... */
 619                 if (fops->add_slave) {
 620                         err = fops->add_slave(sl);
 621                         if (err < 0) {
 622                                 dev_err(&sl->dev,
 623                                         "add_slave() call failed. err=%d\n",
 624                                         err);
 625                                 return err;
 626                         }
 627                 }
 628                 if (fops->groups) {
 629                         err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
 630                         if (err) {
 631                                 dev_err(&sl->dev,
 632                                         "sysfs group creation failed. err=%d\n",
 633                                         err);
 634                                 return err;
 635                         }
 636                 }
 637                 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info) {
 638                         struct device *hwmon
 639                                 = hwmon_device_register_with_info(&sl->dev,
 640                                                 "w1_slave_temp", sl,
 641                                                 fops->chip_info,
 642                                                 NULL);
 643                         if (IS_ERR(hwmon)) {
 644                                 dev_warn(&sl->dev,
 645                                          "could not create hwmon device\n");
 646                         } else {
 647                                 sl->hwmon = hwmon;
 648                         }
 649                 }
 650                 break;
 651         case BUS_NOTIFY_DEL_DEVICE:
 652                 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info &&
 653                             sl->hwmon)
 654                         hwmon_device_unregister(sl->hwmon);
 655                 if (fops->remove_slave)
 656                         sl->family->fops->remove_slave(sl);
 657                 if (fops->groups)
 658                         sysfs_remove_groups(&sl->dev.kobj, fops->groups);
 659                 break;
 660         }
 661         return 0;
 662 }
 663
 664 static int __w1_attach_slave_device(struct w1_slave *sl)
 665 {
 666         int err;
 667
 668         sl->dev.parent = &sl->master->dev;
 669         sl->dev.driver = &w1_slave_driver;
 670         sl->dev.bus = &w1_bus_type;
 671         sl->dev.release = &w1_slave_release;
 672         sl->dev.groups = w1_slave_groups;
 673         sl->dev.of_node = of_find_matching_node(sl->master->dev.of_node,
 674                                                 sl->family->of_match_table);
 675
 676         dev_set_name(&sl->dev, "%02x-%012llx",
 677                  (unsigned int) sl->reg_num.family,
 678                  (unsigned long long) sl->reg_num.id);
 679         snprintf(&sl->name[0], sizeof(sl->name),
 680                  "%02x-%012llx",
 681                  (unsigned int) sl->reg_num.family,
 682                  (unsigned long long) sl->reg_num.id);
 683
 684         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 685                 dev_name(&sl->dev), sl);
 686
 687         /* suppress for w1_family_notify before sending KOBJ_ADD */
 688         dev_set_uevent_suppress(&sl->dev, true);
 689
 690         err = device_register(&sl->dev);
 691         if (err < 0) {
 692                 dev_err(&sl->dev,
 693                         "Device registration [%s] failed. err=%d\n",
 694                         dev_name(&sl->dev), err);
 695                 put_device(&sl->dev);
 696                 return err;
 697         }
 698         w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl);
 699
 700         dev_set_uevent_suppress(&sl->dev, false);
 701         kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
 702
 703         mutex_lock(&sl->master->list_mutex);
 704         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 705         mutex_unlock(&sl->master->list_mutex);
 706
 707         return 0;
 708 }
 709
 710 int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 711 {
 712         struct w1_slave *sl;
 713         struct w1_family *f;
 714         int err;
 715         struct w1_netlink_msg msg;
 716
 717         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 718         if (!sl) {
 719                 dev_err(&dev->dev,
 720                          "%s: failed to allocate new slave device.\n",
 721                          __func__);
 722                 return -ENOMEM;
 723         }
 724
 725
 726         sl->owner = THIS_MODULE;
 727         sl->master = dev;
 728         set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 729
 730         memset(&msg, 0, sizeof(msg));
 731         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 732         atomic_set(&sl->refcnt, 1);
 733         atomic_inc(&sl->master->refcnt);
 734         dev->slave_count++;
 735         dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",
 736                   rn->family, (unsigned long long)rn->id, rn->crc);
 737
 738         /* slave modules need to be loaded in a context with unlocked mutex */
 739         mutex_unlock(&dev->mutex);
 740         request_module("w1-family-0x%02X", rn->family);
 741         mutex_lock(&dev->mutex);
 742
 743         spin_lock(&w1_flock);
 744         f = w1_family_registered(rn->family);
 745         if (!f) {
 746                 f= &w1_default_family;
 747                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 748                           rn->family, rn->family,
 749                           (unsigned long long)rn->id, rn->crc);
 750         }
 751         __w1_family_get(f);
 752         spin_unlock(&w1_flock);
 753
 754         sl->family = f;
 755
 756         err = __w1_attach_slave_device(sl);
 757         if (err < 0) {
 758                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 759                          sl->name);
 760                 dev->slave_count--;
 761                 w1_family_put(sl->family);
 762                 atomic_dec(&sl->master->refcnt);
 763                 kfree(sl);
 764                 return err;
 765         }
 766
 767         sl->ttl = dev->slave_ttl;
 768
 769         memcpy(msg.id.id, rn, sizeof(msg.id));
 770         msg.type = W1_SLAVE_ADD;
 771         w1_netlink_send(dev, &msg);
 772
 773         return 0;
 774 }
 775
 776 int w1_unref_slave(struct w1_slave *sl)
 777 {
 778         struct w1_master *dev = sl->master;
 779         int refcnt;
 780         mutex_lock(&dev->list_mutex);
 781         refcnt = atomic_sub_return(1, &sl->refcnt);
 782         if (refcnt == 0) {
 783                 struct w1_netlink_msg msg;
 784
 785                 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
 786                         sl->name, sl);
 787
 788                 list_del(&sl->w1_slave_entry);
 789
 790                 memset(&msg, 0, sizeof(msg));
 791                 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 792                 msg.type = W1_SLAVE_REMOVE;
 793                 w1_netlink_send(sl->master, &msg);
 794
 795                 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);
 796                 device_unregister(&sl->dev);
 797                 #ifdef DEBUG
 798                 memset(sl, 0, sizeof(*sl));
 799                 #endif
 800                 kfree(sl);
 801         }
 802         atomic_dec(&dev->refcnt);
 803         mutex_unlock(&dev->list_mutex);
 804         return refcnt;
 805 }
 806
 807 int w1_slave_detach(struct w1_slave *sl)
 808 {
 809         /* Only detach a slave once as it decreases the refcnt each time. */
 810         int destroy_now;
 811         mutex_lock(&sl->master->list_mutex);
 812         destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
 813         set_bit(W1_SLAVE_DETACH, &sl->flags);
 814         mutex_unlock(&sl->master->list_mutex);
 815
 816         if (destroy_now)
 817                 destroy_now = !w1_unref_slave(sl);
 818         return destroy_now ? 0 : -EBUSY;
 819 }
 820
 821 struct w1_master *w1_search_master_id(u32 id)
 822 {
 823         struct w1_master *dev;
 824         int found = 0;
 825
 826         mutex_lock(&w1_mlock);
 827         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 828                 if (dev->id == id) {
 829                         found = 1;
 830                         atomic_inc(&dev->refcnt);
 831                         break;
 832                 }
 833         }
 834         mutex_unlock(&w1_mlock);
 835
 836         return (found)?dev:NULL;
 837 }
 838
 839 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 840 {
 841         struct w1_master *dev;
 842         struct w1_slave *sl = NULL;
 843         int found = 0;
 844
 845         mutex_lock(&w1_mlock);
 846         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 847                 mutex_lock(&dev->list_mutex);
 848                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 849                         if (sl->reg_num.family == id->family &&
 850                                         sl->reg_num.id == id->id &&
 851                                         sl->reg_num.crc == id->crc) {
 852                                 found = 1;
 853                                 atomic_inc(&dev->refcnt);
 854                                 atomic_inc(&sl->refcnt);
 855                                 break;
 856                         }
 857                 }
 858                 mutex_unlock(&dev->list_mutex);
 859
 860                 if (found)
 861                         break;
 862         }
 863         mutex_unlock(&w1_mlock);
 864
 865         return (found)?sl:NULL;
 866 }
 867
 868 void w1_reconnect_slaves(struct w1_family *f, int attach)
 869 {
 870         struct w1_slave *sl, *sln;
 871         struct w1_master *dev;
 872
 873         mutex_lock(&w1_mlock);
 874         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 875                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 876                         "for family %02x.\n", dev->name, f->fid);
 877                 mutex_lock(&dev->mutex);
 878                 mutex_lock(&dev->list_mutex);
 879                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 880                         /* If it is a new family, slaves with the default
 881                          * family driver and are that family will be
 882                          * connected.  If the family is going away, devices
 883                          * matching that family are reconneced.
 884                          */
 885                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 886                                 && sl->reg_num.family == f->fid) ||
 887                                 (!attach && sl->family->fid == f->fid)) {
 888                                 struct w1_reg_num rn;
 889
 890                                 mutex_unlock(&dev->list_mutex);
 891                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 892                                 /* If it was already in use let the automatic
 893                                  * scan pick it up again later.
 894                                  */
 895                                 if (!w1_slave_detach(sl))
 896                                         w1_attach_slave_device(dev, &rn);
 897                                 mutex_lock(&dev->list_mutex);
 898                         }
 899                 }
 900                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 901                         "has been finished.\n", dev->name);
 902                 mutex_unlock(&dev->list_mutex);
 903                 mutex_unlock(&dev->mutex);
 904         }
 905         mutex_unlock(&w1_mlock);
 906 }
 907
 908 static int w1_addr_crc_is_valid(struct w1_master *dev, u64 rn)
 909 {
 910         u64 rn_le = cpu_to_le64(rn);
 911         struct w1_reg_num *tmp = (struct w1_reg_num *)&rn;
 912         u8 crc;
 913
 914         crc = w1_calc_crc8((u8 *)&rn_le, 7);
 915
 916         /* quirk:
 917          *   DS28E04 (1w eeprom) has strapping pins to change
 918          *   address, but will not update the crc. So normal rules
 919          *   for consistent w1 addresses are violated. We test
 920          *   with the 7 LSBs of the address forced high.
 921          *
 922          *   (char*)&rn_le = { family, addr_lsb, ..., addr_msb, crc }.
 923          */
 924         if (crc != tmp->crc && tmp->family == W1_FAMILY_DS28E04) {
 925                 u64 corr_le = rn_le;
 926
 927                 ((u8 *)&corr_le)[1] |= 0x7f;
 928                 crc = w1_calc_crc8((u8 *)&corr_le, 7);
 929
 930                 dev_info(&dev->dev, "DS28E04 crc workaround on %02x.%012llx.%02x\n",
 931                         tmp->family, (unsigned long long)tmp->id, tmp->crc);
 932         }
 933
 934         if (crc != tmp->crc) {
 935                 dev_dbg(&dev->dev, "w1 addr crc mismatch: %02x.%012llx.%02x != 0x%02x.\n",
 936                         tmp->family, (unsigned long long)tmp->id, tmp->crc, crc);
 937                 return 0;
 938         }
 939         return 1;
 940 }
 941
 942 void w1_slave_found(struct w1_master *dev, u64 rn)
 943 {
 944         struct w1_slave *sl;
 945         struct w1_reg_num *tmp;
 946
 947         atomic_inc(&dev->refcnt);
 948
 949         tmp = (struct w1_reg_num *) &rn;
 950
 951         sl = w1_slave_search_device(dev, tmp);
 952         if (sl) {
 953                 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 954         } else {
 955                 if (rn && w1_addr_crc_is_valid(dev, rn))
 956                         w1_attach_slave_device(dev, tmp);
 957         }
 958
 959         atomic_dec(&dev->refcnt);
 960 }
 961
 962 /**
 963  * w1_search() - Performs a ROM Search & registers any devices found.
 964  * @dev: The master device to search
 965  * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH
 966  * to return only devices in the alarmed state
 967  * @cb: Function to call when a device is found
 968  *
 969  * The 1-wire search is a simple binary tree search.
 970  * For each bit of the address, we read two bits and write one bit.
 971  * The bit written will put to sleep all devies that don't match that bit.
 972  * When the two reads differ, the direction choice is obvious.
 973  * When both bits are 0, we must choose a path to take.
 974  * When we can scan all 64 bits without having to choose a path, we are done.
 975  *
 976  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 977  *
 978  */
 979 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 980 {
 981         u64 last_rn, rn, tmp64;
 982         int i, slave_count = 0;
 983         int last_zero, last_device;
 984         int search_bit, desc_bit;
 985         u8  triplet_ret = 0;
 986
 987         search_bit = 0;
 988         rn = dev->search_id;
 989         last_rn = 0;
 990         last_device = 0;
 991         last_zero = -1;
 992
 993         desc_bit = 64;
 994
 995         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 996                 last_rn = rn;
 997                 rn = 0;
 998
 999                 /*
1000                  * Reset bus and all 1-wire device state machines
1001                  * so they can respond to our requests.
1002                  *
1003                  * Return 0 - device(s) present, 1 - no devices present.
1004                  */
1005                 mutex_lock(&dev->bus_mutex);
1006                 if (w1_reset_bus(dev)) {
1007                         mutex_unlock(&dev->bus_mutex);
1008                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
1009                         break;
1010                 }
1011
1012                 /* Do fast search on single slave bus */
1013                 if (dev->max_slave_count == 1) {
1014                         int rv;
1015                         w1_write_8(dev, W1_READ_ROM);
1016                         rv = w1_read_block(dev, (u8 *)&rn, 8);
1017                         mutex_unlock(&dev->bus_mutex);
1018
1019                         if (rv == 8 && rn)
1020                                 cb(dev, rn);
1021
1022                         break;
1023                 }
1024
1025                 /* Start the search */
1026                 w1_write_8(dev, search_type);
1027                 for (i = 0; i < 64; ++i) {
1028                         /* Determine the direction/search bit */
1029                         if (i == desc_bit)
1030                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
1031                         else if (i > desc_bit)
1032                                 search_bit = 0;   /* take the 0 path on the next branch */
1033                         else
1034                                 search_bit = ((last_rn >> i) & 0x1);
1035
1036                         /* Read two bits and write one bit */
1037                         triplet_ret = w1_triplet(dev, search_bit);
1038
1039                         /* quit if no device responded */
1040                         if ( (triplet_ret & 0x03) == 0x03 )
1041                                 break;
1042
1043                         /* If both directions were valid, and we took the 0 path... */
1044                         if (triplet_ret == 0)
1045                                 last_zero = i;
1046
1047                         /* extract the direction taken & update the device number */
1048                         tmp64 = (triplet_ret >> 2);
1049                         rn |= (tmp64 << i);
1050
1051                         if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
1052                                 mutex_unlock(&dev->bus_mutex);
1053                                 dev_dbg(&dev->dev, "Abort w1_search\n");
1054                                 return;
1055                         }
1056                 }
1057                 mutex_unlock(&dev->bus_mutex);
1058
1059                 if ( (triplet_ret & 0x03) != 0x03 ) {
1060                         if ((desc_bit == last_zero) || (last_zero < 0)) {
1061                                 last_device = 1;
1062                                 dev->search_id = 0;
1063                         } else {
1064                                 dev->search_id = rn;
1065                         }
1066                         desc_bit = last_zero;
1067                         cb(dev, rn);
1068                 }
1069
1070                 if (!last_device && slave_count == dev->max_slave_count &&
1071                         !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
1072                         /* Only max_slave_count will be scanned in a search,
1073                          * but it will start where it left off next search
1074                          * until all ids are identified and then it will start
1075                          * over.  A continued search will report the previous
1076                          * last id as the first id (provided it is still on the
1077                          * bus).
1078                          */
1079                         dev_info(&dev->dev, "%s: max_slave_count %d reached, "
1080                                 "will continue next search.\n", __func__,
1081                                 dev->max_slave_count);
1082                         set_bit(W1_WARN_MAX_COUNT, &dev->flags);
1083                 }
1084         }
1085 }
1086
1087 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
1088         w1_slave_found_callback cb)
1089 {
1090         struct w1_slave *sl, *sln;
1091
1092         mutex_lock(&dev->list_mutex);
1093         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
1094                 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
1095         mutex_unlock(&dev->list_mutex);
1096
1097         w1_search_devices(dev, search_type, cb);
1098
1099         mutex_lock(&dev->list_mutex);
1100         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
1101                 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
1102                         mutex_unlock(&dev->list_mutex);
1103                         w1_slave_detach(sl);
1104                         mutex_lock(&dev->list_mutex);
1105                 }
1106                 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
1107                         sl->ttl = dev->slave_ttl;
1108         }
1109         mutex_unlock(&dev->list_mutex);
1110
1111         if (dev->search_count > 0)
1112                 dev->search_count--;
1113 }
1114
1115 static void w1_search_process(struct w1_master *dev, u8 search_type)
1116 {
1117         w1_search_process_cb(dev, search_type, w1_slave_found);
1118 }
1119
1120 /**
1121  * w1_process_callbacks() - execute each dev->async_list callback entry
1122  * @dev: w1_master device
1123  *
1124  * The w1 master list_mutex must be held.
1125  *
1126  * Return: 1 if there were commands to executed 0 otherwise
1127  */
1128 int w1_process_callbacks(struct w1_master *dev)
1129 {
1130         int ret = 0;
1131         struct w1_async_cmd *async_cmd, *async_n;
1132
1133         /* The list can be added to in another thread, loop until it is empty */
1134         while (!list_empty(&dev->async_list)) {
1135                 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
1136                         async_entry) {
1137                         /* drop the lock, if it is a search it can take a long
1138                          * time */
1139                         mutex_unlock(&dev->list_mutex);
1140                         async_cmd->cb(dev, async_cmd);
1141                         ret = 1;
1142                         mutex_lock(&dev->list_mutex);
1143                 }
1144         }
1145         return ret;
1146 }
1147
1148 int w1_process(void *data)
1149 {
1150         struct w1_master *dev = (struct w1_master *) data;
1151         /* As long as w1_timeout is only set by a module parameter the sleep
1152          * time can be calculated in jiffies once.
1153          */
1154         const unsigned long jtime =
1155           usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);
1156         /* remainder if it woke up early */
1157         unsigned long jremain = 0;
1158
1159         atomic_inc(&dev->refcnt);
1160
1161         for (;;) {
1162
1163                 if (!jremain && dev->search_count) {
1164                         mutex_lock(&dev->mutex);
1165                         w1_search_process(dev, W1_SEARCH);
1166                         mutex_unlock(&dev->mutex);
1167                 }
1168
1169                 mutex_lock(&dev->list_mutex);
1170                 /* Note, w1_process_callback drops the lock while processing,
1171                  * but locks it again before returning.
1172                  */
1173                 if (!w1_process_callbacks(dev) && jremain) {
1174                         /* a wake up is either to stop the thread, process
1175                          * callbacks, or search, it isn't process callbacks, so
1176                          * schedule a search.
1177                          */
1178                         jremain = 1;
1179                 }
1180
1181                 __set_current_state(TASK_INTERRUPTIBLE);
1182
1183                 /* hold list_mutex until after interruptible to prevent loosing
1184                  * the wakeup signal when async_cmd is added.
1185                  */
1186                 mutex_unlock(&dev->list_mutex);
1187
1188                 if (kthread_should_stop()) {
1189                         __set_current_state(TASK_RUNNING);
1190                         break;
1191                 }
1192
1193                 /* Only sleep when the search is active. */
1194                 if (dev->search_count) {
1195                         if (!jremain)
1196                                 jremain = jtime;
1197                         jremain = schedule_timeout(jremain);
1198                 }
1199                 else
1200                         schedule();
1201         }
1202
1203         atomic_dec(&dev->refcnt);
1204
1205         return 0;
1206 }
1207
1208 static int __init w1_init(void)
1209 {
1210         int retval;
1211
1212         pr_info("Driver for 1-wire Dallas network protocol.\n");
1213
1214         w1_init_netlink();
1215
1216         retval = bus_register(&w1_bus_type);
1217         if (retval) {
1218                 pr_err("Failed to register bus. err=%d.\n", retval);
1219                 goto err_out_exit_init;
1220         }
1221
1222         retval = driver_register(&w1_master_driver);
1223         if (retval) {
1224                 pr_err("Failed to register master driver. err=%d.\n",
1225                         retval);
1226                 goto err_out_bus_unregister;
1227         }
1228
1229         retval = driver_register(&w1_slave_driver);
1230         if (retval) {
1231                 pr_err("Failed to register slave driver. err=%d.\n",
1232                         retval);
1233                 goto err_out_master_unregister;
1234         }
1235
1236         return 0;
1237
1238 #if 0
1239 /* For undoing the slave register if there was a step after it. */
1240 err_out_slave_unregister:
1241         driver_unregister(&w1_slave_driver);
1242 #endif
1243
1244 err_out_master_unregister:
1245         driver_unregister(&w1_master_driver);
1246
1247 err_out_bus_unregister:
1248         bus_unregister(&w1_bus_type);
1249
1250 err_out_exit_init:
1251         return retval;
1252 }
1253
1254 static void __exit w1_fini(void)
1255 {
1256         struct w1_master *dev;
1257
1258         /* Set netlink removal messages and some cleanup */
1259         list_for_each_entry(dev, &w1_masters, w1_master_entry)
1260                 __w1_remove_master_device(dev);
1261
1262         w1_fini_netlink();
1263
1264         driver_unregister(&w1_slave_driver);
1265         driver_unregister(&w1_master_driver);
1266         bus_unregister(&w1_bus_type);
1267 }
1268
1269 module_init(w1_init);
1270 module_exit(w1_fini);
1271
1272 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
1273 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
1274 MODULE_LICENSE("GPL");