1 /* 2 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 */ 14 15 #include <linux/delay.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/moduleparam.h> 19 #include <linux/list.h> 20 #include <linux/interrupt.h> 21 #include <linux/spinlock.h> 22 #include <linux/timer.h> 23 #include <linux/device.h> 24 #include <linux/slab.h> 25 #include <linux/sched.h> 26 #include <linux/kthread.h> 27 #include <linux/freezer.h> 28 #include <linux/hwmon.h> 29 30 #include <linux/atomic.h> 31 32 #include "w1_internal.h" 33 #include "w1_netlink.h" 34 35 #define W1_FAMILY_DEFAULT 0 36 37 static int w1_timeout = 10; 38 module_param_named(timeout, w1_timeout, int, 0); 39 MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches"); 40 41 static int w1_timeout_us = 0; 42 module_param_named(timeout_us, w1_timeout_us, int, 0); 43 MODULE_PARM_DESC(timeout_us, 44 "time in microseconds between automatic slave searches"); 45 46 /* A search stops when w1_max_slave_count devices have been found in that 47 * search. The next search will start over and detect the same set of devices 48 * on a static 1-wire bus. Memory is not allocated based on this number, just 49 * on the number of devices known to the kernel. Having a high number does not 50 * consume additional resources. As a special case, if there is only one 51 * device on the network and w1_max_slave_count is set to 1, the device id can 52 * be read directly skipping the normal slower search process. 53 */ 54 int w1_max_slave_count = 64; 55 module_param_named(max_slave_count, w1_max_slave_count, int, 0); 56 MODULE_PARM_DESC(max_slave_count, 57 "maximum number of slaves detected in a search"); 58 59 int w1_max_slave_ttl = 10; 60 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); 61 MODULE_PARM_DESC(slave_ttl, 62 "Number of searches not seeing a slave before it will be removed"); 63 64 DEFINE_MUTEX(w1_mlock); 65 LIST_HEAD(w1_masters); 66 67 static int w1_master_match(struct device *dev, struct device_driver *drv) 68 { 69 return 1; 70 } 71 72 static int w1_master_probe(struct device *dev) 73 { 74 return -ENODEV; 75 } 76 77 static void w1_master_release(struct device *dev) 78 { 79 struct w1_master *md = dev_to_w1_master(dev); 80 81 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); 82 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 83 kfree(md); 84 } 85 86 static void w1_slave_release(struct device *dev) 87 { 88 struct w1_slave *sl = dev_to_w1_slave(dev); 89 90 dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl); 91 92 w1_family_put(sl->family); 93 sl->master->slave_count--; 94 } 95 96 static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) 97 { 98 struct w1_slave *sl = dev_to_w1_slave(dev); 99 100 return sprintf(buf, "%s\n", sl->name); 101 } 102 static DEVICE_ATTR_RO(name); 103 104 static ssize_t id_show(struct device *dev, 105 struct device_attribute *attr, char *buf) 106 { 107 struct w1_slave *sl = dev_to_w1_slave(dev); 108 ssize_t count = sizeof(sl->reg_num); 109 110 memcpy(buf, (u8 *)&sl->reg_num, count); 111 return count; 112 } 113 static DEVICE_ATTR_RO(id); 114 115 static struct attribute *w1_slave_attrs[] = { 116 &dev_attr_name.attr, 117 &dev_attr_id.attr, 118 NULL, 119 }; 120 ATTRIBUTE_GROUPS(w1_slave); 121 122 /* Default family */ 123 124 static ssize_t rw_write(struct file *filp, struct kobject *kobj, 125 struct bin_attribute *bin_attr, char *buf, loff_t off, 126 size_t count) 127 { 128 struct w1_slave *sl = kobj_to_w1_slave(kobj); 129 130 mutex_lock(&sl->master->mutex); 131 if (w1_reset_select_slave(sl)) { 132 count = 0; 133 goto out_up; 134 } 135 136 w1_write_block(sl->master, buf, count); 137 138 out_up: 139 mutex_unlock(&sl->master->mutex); 140 return count; 141 } 142 143 static ssize_t rw_read(struct file *filp, struct kobject *kobj, 144 struct bin_attribute *bin_attr, char *buf, loff_t off, 145 size_t count) 146 { 147 struct w1_slave *sl = kobj_to_w1_slave(kobj); 148 149 mutex_lock(&sl->master->mutex); 150 w1_read_block(sl->master, buf, count); 151 mutex_unlock(&sl->master->mutex); 152 return count; 153 } 154 155 static BIN_ATTR_RW(rw, PAGE_SIZE); 156 157 static struct bin_attribute *w1_slave_bin_attrs[] = { 158 &bin_attr_rw, 159 NULL, 160 }; 161 162 static const struct attribute_group w1_slave_default_group = { 163 .bin_attrs = w1_slave_bin_attrs, 164 }; 165 166 static const struct attribute_group *w1_slave_default_groups[] = { 167 &w1_slave_default_group, 168 NULL, 169 }; 170 171 static struct w1_family_ops w1_default_fops = { 172 .groups = w1_slave_default_groups, 173 }; 174 175 static struct w1_family w1_default_family = { 176 .fops = &w1_default_fops, 177 }; 178 179 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env); 180 181 static struct bus_type w1_bus_type = { 182 .name = "w1", 183 .match = w1_master_match, 184 .uevent = w1_uevent, 185 }; 186 187 struct device_driver w1_master_driver = { 188 .name = "w1_master_driver", 189 .bus = &w1_bus_type, 190 .probe = w1_master_probe, 191 }; 192 193 struct device w1_master_device = { 194 .parent = NULL, 195 .bus = &w1_bus_type, 196 .init_name = "w1 bus master", 197 .driver = &w1_master_driver, 198 .release = &w1_master_release 199 }; 200 201 static struct device_driver w1_slave_driver = { 202 .name = "w1_slave_driver", 203 .bus = &w1_bus_type, 204 }; 205 206 #if 0 207 struct device w1_slave_device = { 208 .parent = NULL, 209 .bus = &w1_bus_type, 210 .init_name = "w1 bus slave", 211 .driver = &w1_slave_driver, 212 .release = &w1_slave_release 213 }; 214 #endif /* 0 */ 215 216 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) 217 { 218 struct w1_master *md = dev_to_w1_master(dev); 219 ssize_t count; 220 221 mutex_lock(&md->mutex); 222 count = sprintf(buf, "%s\n", md->name); 223 mutex_unlock(&md->mutex); 224 225 return count; 226 } 227 228 static ssize_t w1_master_attribute_store_search(struct device * dev, 229 struct device_attribute *attr, 230 const char * buf, size_t count) 231 { 232 long tmp; 233 struct w1_master *md = dev_to_w1_master(dev); 234 int ret; 235 236 ret = kstrtol(buf, 0, &tmp); 237 if (ret) 238 return ret; 239 240 mutex_lock(&md->mutex); 241 md->search_count = tmp; 242 mutex_unlock(&md->mutex); 243 /* Only wake if it is going to be searching. */ 244 if (tmp) 245 wake_up_process(md->thread); 246 247 return count; 248 } 249 250 static ssize_t w1_master_attribute_show_search(struct device *dev, 251 struct device_attribute *attr, 252 char *buf) 253 { 254 struct w1_master *md = dev_to_w1_master(dev); 255 ssize_t count; 256 257 mutex_lock(&md->mutex); 258 count = sprintf(buf, "%d\n", md->search_count); 259 mutex_unlock(&md->mutex); 260 261 return count; 262 } 263 264 static ssize_t w1_master_attribute_store_pullup(struct device *dev, 265 struct device_attribute *attr, 266 const char *buf, size_t count) 267 { 268 long tmp; 269 struct w1_master *md = dev_to_w1_master(dev); 270 int ret; 271 272 ret = kstrtol(buf, 0, &tmp); 273 if (ret) 274 return ret; 275 276 mutex_lock(&md->mutex); 277 md->enable_pullup = tmp; 278 mutex_unlock(&md->mutex); 279 280 return count; 281 } 282 283 static ssize_t w1_master_attribute_show_pullup(struct device *dev, 284 struct device_attribute *attr, 285 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, "%d\n", md->enable_pullup); 292 mutex_unlock(&md->mutex); 293 294 return count; 295 } 296 297 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) 298 { 299 struct w1_master *md = dev_to_w1_master(dev); 300 ssize_t count; 301 302 mutex_lock(&md->mutex); 303 count = sprintf(buf, "0x%p\n", md->bus_master); 304 mutex_unlock(&md->mutex); 305 return count; 306 } 307 308 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) 309 { 310 ssize_t count; 311 count = sprintf(buf, "%d\n", w1_timeout); 312 return count; 313 } 314 315 static ssize_t w1_master_attribute_show_timeout_us(struct device *dev, 316 struct device_attribute *attr, char *buf) 317 { 318 ssize_t count; 319 count = sprintf(buf, "%d\n", w1_timeout_us); 320 return count; 321 } 322 323 static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev, 324 struct device_attribute *attr, const char *buf, size_t count) 325 { 326 int tmp; 327 struct w1_master *md = dev_to_w1_master(dev); 328 329 if (kstrtoint(buf, 0, &tmp) || tmp < 1) 330 return -EINVAL; 331 332 mutex_lock(&md->mutex); 333 md->max_slave_count = tmp; 334 /* allow each time the max_slave_count is updated */ 335 clear_bit(W1_WARN_MAX_COUNT, &md->flags); 336 mutex_unlock(&md->mutex); 337 338 return count; 339 } 340 341 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 342 { 343 struct w1_master *md = dev_to_w1_master(dev); 344 ssize_t count; 345 346 mutex_lock(&md->mutex); 347 count = sprintf(buf, "%d\n", md->max_slave_count); 348 mutex_unlock(&md->mutex); 349 return count; 350 } 351 352 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) 353 { 354 struct w1_master *md = dev_to_w1_master(dev); 355 ssize_t count; 356 357 mutex_lock(&md->mutex); 358 count = sprintf(buf, "%lu\n", md->attempts); 359 mutex_unlock(&md->mutex); 360 return count; 361 } 362 363 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 364 { 365 struct w1_master *md = dev_to_w1_master(dev); 366 ssize_t count; 367 368 mutex_lock(&md->mutex); 369 count = sprintf(buf, "%d\n", md->slave_count); 370 mutex_unlock(&md->mutex); 371 return count; 372 } 373 374 static ssize_t w1_master_attribute_show_slaves(struct device *dev, 375 struct device_attribute *attr, char *buf) 376 { 377 struct w1_master *md = dev_to_w1_master(dev); 378 int c = PAGE_SIZE; 379 struct list_head *ent, *n; 380 struct w1_slave *sl = NULL; 381 382 mutex_lock(&md->list_mutex); 383 384 list_for_each_safe(ent, n, &md->slist) { 385 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 386 387 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); 388 } 389 if (!sl) 390 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); 391 392 mutex_unlock(&md->list_mutex); 393 394 return PAGE_SIZE - c; 395 } 396 397 static ssize_t w1_master_attribute_show_add(struct device *dev, 398 struct device_attribute *attr, char *buf) 399 { 400 int c = PAGE_SIZE; 401 c -= snprintf(buf+PAGE_SIZE - c, c, 402 "write device id xx-xxxxxxxxxxxx to add slave\n"); 403 return PAGE_SIZE - c; 404 } 405 406 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count, 407 struct w1_reg_num *rn) 408 { 409 unsigned int family; 410 unsigned long long id; 411 int i; 412 u64 rn64_le; 413 414 /* The CRC value isn't read from the user because the sysfs directory 415 * doesn't include it and most messages from the bus search don't 416 * print it either. It would be unreasonable for the user to then 417 * provide it. 418 */ 419 const char *error_msg = "bad slave string format, expecting " 420 "ff-dddddddddddd\n"; 421 422 if (buf[2] != '-') { 423 dev_err(dev, "%s", error_msg); 424 return -EINVAL; 425 } 426 i = sscanf(buf, "%02x-%012llx", &family, &id); 427 if (i != 2) { 428 dev_err(dev, "%s", error_msg); 429 return -EINVAL; 430 } 431 rn->family = family; 432 rn->id = id; 433 434 rn64_le = cpu_to_le64(*(u64 *)rn); 435 rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7); 436 437 #if 0 438 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n", 439 rn->family, (unsigned long long)rn->id, rn->crc); 440 #endif 441 442 return 0; 443 } 444 445 /* Searches the slaves in the w1_master and returns a pointer or NULL. 446 * Note: must not hold list_mutex 447 */ 448 struct w1_slave *w1_slave_search_device(struct w1_master *dev, 449 struct w1_reg_num *rn) 450 { 451 struct w1_slave *sl; 452 mutex_lock(&dev->list_mutex); 453 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 454 if (sl->reg_num.family == rn->family && 455 sl->reg_num.id == rn->id && 456 sl->reg_num.crc == rn->crc) { 457 mutex_unlock(&dev->list_mutex); 458 return sl; 459 } 460 } 461 mutex_unlock(&dev->list_mutex); 462 return NULL; 463 } 464 465 static ssize_t w1_master_attribute_store_add(struct device *dev, 466 struct device_attribute *attr, 467 const char *buf, size_t count) 468 { 469 struct w1_master *md = dev_to_w1_master(dev); 470 struct w1_reg_num rn; 471 struct w1_slave *sl; 472 ssize_t result = count; 473 474 if (w1_atoreg_num(dev, buf, count, &rn)) 475 return -EINVAL; 476 477 mutex_lock(&md->mutex); 478 sl = w1_slave_search_device(md, &rn); 479 /* It would be nice to do a targeted search one the one-wire bus 480 * for the new device to see if it is out there or not. But the 481 * current search doesn't support that. 482 */ 483 if (sl) { 484 dev_info(dev, "Device %s already exists\n", sl->name); 485 result = -EINVAL; 486 } else { 487 w1_attach_slave_device(md, &rn); 488 } 489 mutex_unlock(&md->mutex); 490 491 return result; 492 } 493 494 static ssize_t w1_master_attribute_show_remove(struct device *dev, 495 struct device_attribute *attr, char *buf) 496 { 497 int c = PAGE_SIZE; 498 c -= snprintf(buf+PAGE_SIZE - c, c, 499 "write device id xx-xxxxxxxxxxxx to remove slave\n"); 500 return PAGE_SIZE - c; 501 } 502 503 static ssize_t w1_master_attribute_store_remove(struct device *dev, 504 struct device_attribute *attr, 505 const char *buf, size_t count) 506 { 507 struct w1_master *md = dev_to_w1_master(dev); 508 struct w1_reg_num rn; 509 struct w1_slave *sl; 510 ssize_t result = count; 511 512 if (w1_atoreg_num(dev, buf, count, &rn)) 513 return -EINVAL; 514 515 mutex_lock(&md->mutex); 516 sl = w1_slave_search_device(md, &rn); 517 if (sl) { 518 result = w1_slave_detach(sl); 519 /* refcnt 0 means it was detached in the call */ 520 if (result == 0) 521 result = count; 522 } else { 523 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family, 524 (unsigned long long)rn.id); 525 result = -EINVAL; 526 } 527 mutex_unlock(&md->mutex); 528 529 return result; 530 } 531 532 #define W1_MASTER_ATTR_RO(_name, _mode) \ 533 struct device_attribute w1_master_attribute_##_name = \ 534 __ATTR(w1_master_##_name, _mode, \ 535 w1_master_attribute_show_##_name, NULL) 536 537 #define W1_MASTER_ATTR_RW(_name, _mode) \ 538 struct device_attribute w1_master_attribute_##_name = \ 539 __ATTR(w1_master_##_name, _mode, \ 540 w1_master_attribute_show_##_name, \ 541 w1_master_attribute_store_##_name) 542 543 static W1_MASTER_ATTR_RO(name, S_IRUGO); 544 static W1_MASTER_ATTR_RO(slaves, S_IRUGO); 545 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); 546 static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP); 547 static W1_MASTER_ATTR_RO(attempts, S_IRUGO); 548 static W1_MASTER_ATTR_RO(timeout, S_IRUGO); 549 static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO); 550 static W1_MASTER_ATTR_RO(pointer, S_IRUGO); 551 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP); 552 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP); 553 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP); 554 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP); 555 556 static struct attribute *w1_master_default_attrs[] = { 557 &w1_master_attribute_name.attr, 558 &w1_master_attribute_slaves.attr, 559 &w1_master_attribute_slave_count.attr, 560 &w1_master_attribute_max_slave_count.attr, 561 &w1_master_attribute_attempts.attr, 562 &w1_master_attribute_timeout.attr, 563 &w1_master_attribute_timeout_us.attr, 564 &w1_master_attribute_pointer.attr, 565 &w1_master_attribute_search.attr, 566 &w1_master_attribute_pullup.attr, 567 &w1_master_attribute_add.attr, 568 &w1_master_attribute_remove.attr, 569 NULL 570 }; 571 572 static const struct attribute_group w1_master_defattr_group = { 573 .attrs = w1_master_default_attrs, 574 }; 575 576 int w1_create_master_attributes(struct w1_master *master) 577 { 578 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); 579 } 580 581 void w1_destroy_master_attributes(struct w1_master *master) 582 { 583 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); 584 } 585 586 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env) 587 { 588 struct w1_master *md = NULL; 589 struct w1_slave *sl = NULL; 590 char *event_owner, *name; 591 int err = 0; 592 593 if (dev->driver == &w1_master_driver) { 594 md = container_of(dev, struct w1_master, dev); 595 event_owner = "master"; 596 name = md->name; 597 } else if (dev->driver == &w1_slave_driver) { 598 sl = container_of(dev, struct w1_slave, dev); 599 event_owner = "slave"; 600 name = sl->name; 601 } else { 602 dev_dbg(dev, "Unknown event.\n"); 603 return -EINVAL; 604 } 605 606 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", 607 event_owner, name, dev_name(dev)); 608 609 if (dev->driver != &w1_slave_driver || !sl) 610 goto end; 611 612 err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family); 613 if (err) 614 goto end; 615 616 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX", 617 (unsigned long long)sl->reg_num.id); 618 end: 619 return err; 620 } 621 622 static int w1_family_notify(unsigned long action, struct w1_slave *sl) 623 { 624 struct w1_family_ops *fops; 625 int err; 626 627 fops = sl->family->fops; 628 629 if (!fops) 630 return 0; 631 632 switch (action) { 633 case BUS_NOTIFY_ADD_DEVICE: 634 /* if the family driver needs to initialize something... */ 635 if (fops->add_slave) { 636 err = fops->add_slave(sl); 637 if (err < 0) { 638 dev_err(&sl->dev, 639 "add_slave() call failed. err=%d\n", 640 err); 641 return err; 642 } 643 } 644 if (fops->groups) { 645 err = sysfs_create_groups(&sl->dev.kobj, fops->groups); 646 if (err) { 647 dev_err(&sl->dev, 648 "sysfs group creation failed. err=%d\n", 649 err); 650 return err; 651 } 652 } 653 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info) { 654 struct device *hwmon 655 = hwmon_device_register_with_info(&sl->dev, 656 "w1_slave_temp", sl, 657 fops->chip_info, 658 NULL); 659 if (IS_ERR(hwmon)) { 660 dev_warn(&sl->dev, 661 "could not create hwmon device\n"); 662 } else { 663 sl->hwmon = hwmon; 664 } 665 } 666 break; 667 case BUS_NOTIFY_DEL_DEVICE: 668 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info && 669 sl->hwmon) 670 hwmon_device_unregister(sl->hwmon); 671 if (fops->remove_slave) 672 sl->family->fops->remove_slave(sl); 673 if (fops->groups) 674 sysfs_remove_groups(&sl->dev.kobj, fops->groups); 675 break; 676 } 677 return 0; 678 } 679 680 static int __w1_attach_slave_device(struct w1_slave *sl) 681 { 682 int err; 683 684 sl->dev.parent = &sl->master->dev; 685 sl->dev.driver = &w1_slave_driver; 686 sl->dev.bus = &w1_bus_type; 687 sl->dev.release = &w1_slave_release; 688 sl->dev.groups = w1_slave_groups; 689 690 dev_set_name(&sl->dev, "%02x-%012llx", 691 (unsigned int) sl->reg_num.family, 692 (unsigned long long) sl->reg_num.id); 693 snprintf(&sl->name[0], sizeof(sl->name), 694 "%02x-%012llx", 695 (unsigned int) sl->reg_num.family, 696 (unsigned long long) sl->reg_num.id); 697 698 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, 699 dev_name(&sl->dev), sl); 700 701 /* suppress for w1_family_notify before sending KOBJ_ADD */ 702 dev_set_uevent_suppress(&sl->dev, true); 703 704 err = device_register(&sl->dev); 705 if (err < 0) { 706 dev_err(&sl->dev, 707 "Device registration [%s] failed. err=%d\n", 708 dev_name(&sl->dev), err); 709 put_device(&sl->dev); 710 return err; 711 } 712 w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl); 713 714 dev_set_uevent_suppress(&sl->dev, false); 715 kobject_uevent(&sl->dev.kobj, KOBJ_ADD); 716 717 mutex_lock(&sl->master->list_mutex); 718 list_add_tail(&sl->w1_slave_entry, &sl->master->slist); 719 mutex_unlock(&sl->master->list_mutex); 720 721 return 0; 722 } 723 724 int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 725 { 726 struct w1_slave *sl; 727 struct w1_family *f; 728 int err; 729 struct w1_netlink_msg msg; 730 731 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL); 732 if (!sl) { 733 dev_err(&dev->dev, 734 "%s: failed to allocate new slave device.\n", 735 __func__); 736 return -ENOMEM; 737 } 738 739 740 sl->owner = THIS_MODULE; 741 sl->master = dev; 742 set_bit(W1_SLAVE_ACTIVE, &sl->flags); 743 744 memset(&msg, 0, sizeof(msg)); 745 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); 746 atomic_set(&sl->refcnt, 1); 747 atomic_inc(&sl->master->refcnt); 748 dev->slave_count++; 749 dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n", 750 rn->family, (unsigned long long)rn->id, rn->crc); 751 752 /* slave modules need to be loaded in a context with unlocked mutex */ 753 mutex_unlock(&dev->mutex); 754 request_module("w1-family-0x%02X", rn->family); 755 mutex_lock(&dev->mutex); 756 757 spin_lock(&w1_flock); 758 f = w1_family_registered(rn->family); 759 if (!f) { 760 f= &w1_default_family; 761 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", 762 rn->family, rn->family, 763 (unsigned long long)rn->id, rn->crc); 764 } 765 __w1_family_get(f); 766 spin_unlock(&w1_flock); 767 768 sl->family = f; 769 770 err = __w1_attach_slave_device(sl); 771 if (err < 0) { 772 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, 773 sl->name); 774 dev->slave_count--; 775 w1_family_put(sl->family); 776 atomic_dec(&sl->master->refcnt); 777 kfree(sl); 778 return err; 779 } 780 781 sl->ttl = dev->slave_ttl; 782 783 memcpy(msg.id.id, rn, sizeof(msg.id)); 784 msg.type = W1_SLAVE_ADD; 785 w1_netlink_send(dev, &msg); 786 787 return 0; 788 } 789 790 int w1_unref_slave(struct w1_slave *sl) 791 { 792 struct w1_master *dev = sl->master; 793 int refcnt; 794 mutex_lock(&dev->list_mutex); 795 refcnt = atomic_sub_return(1, &sl->refcnt); 796 if (refcnt == 0) { 797 struct w1_netlink_msg msg; 798 799 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, 800 sl->name, sl); 801 802 list_del(&sl->w1_slave_entry); 803 804 memset(&msg, 0, sizeof(msg)); 805 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); 806 msg.type = W1_SLAVE_REMOVE; 807 w1_netlink_send(sl->master, &msg); 808 809 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl); 810 device_unregister(&sl->dev); 811 #ifdef DEBUG 812 memset(sl, 0, sizeof(*sl)); 813 #endif 814 kfree(sl); 815 } 816 atomic_dec(&dev->refcnt); 817 mutex_unlock(&dev->list_mutex); 818 return refcnt; 819 } 820 821 int w1_slave_detach(struct w1_slave *sl) 822 { 823 /* Only detach a slave once as it decreases the refcnt each time. */ 824 int destroy_now; 825 mutex_lock(&sl->master->list_mutex); 826 destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags); 827 set_bit(W1_SLAVE_DETACH, &sl->flags); 828 mutex_unlock(&sl->master->list_mutex); 829 830 if (destroy_now) 831 destroy_now = !w1_unref_slave(sl); 832 return destroy_now ? 0 : -EBUSY; 833 } 834 835 struct w1_master *w1_search_master_id(u32 id) 836 { 837 struct w1_master *dev; 838 int found = 0; 839 840 mutex_lock(&w1_mlock); 841 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 842 if (dev->id == id) { 843 found = 1; 844 atomic_inc(&dev->refcnt); 845 break; 846 } 847 } 848 mutex_unlock(&w1_mlock); 849 850 return (found)?dev:NULL; 851 } 852 853 struct w1_slave *w1_search_slave(struct w1_reg_num *id) 854 { 855 struct w1_master *dev; 856 struct w1_slave *sl = NULL; 857 int found = 0; 858 859 mutex_lock(&w1_mlock); 860 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 861 mutex_lock(&dev->list_mutex); 862 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 863 if (sl->reg_num.family == id->family && 864 sl->reg_num.id == id->id && 865 sl->reg_num.crc == id->crc) { 866 found = 1; 867 atomic_inc(&dev->refcnt); 868 atomic_inc(&sl->refcnt); 869 break; 870 } 871 } 872 mutex_unlock(&dev->list_mutex); 873 874 if (found) 875 break; 876 } 877 mutex_unlock(&w1_mlock); 878 879 return (found)?sl:NULL; 880 } 881 882 void w1_reconnect_slaves(struct w1_family *f, int attach) 883 { 884 struct w1_slave *sl, *sln; 885 struct w1_master *dev; 886 887 mutex_lock(&w1_mlock); 888 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 889 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 890 "for family %02x.\n", dev->name, f->fid); 891 mutex_lock(&dev->mutex); 892 mutex_lock(&dev->list_mutex); 893 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 894 /* If it is a new family, slaves with the default 895 * family driver and are that family will be 896 * connected. If the family is going away, devices 897 * matching that family are reconneced. 898 */ 899 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT 900 && sl->reg_num.family == f->fid) || 901 (!attach && sl->family->fid == f->fid)) { 902 struct w1_reg_num rn; 903 904 mutex_unlock(&dev->list_mutex); 905 memcpy(&rn, &sl->reg_num, sizeof(rn)); 906 /* If it was already in use let the automatic 907 * scan pick it up again later. 908 */ 909 if (!w1_slave_detach(sl)) 910 w1_attach_slave_device(dev, &rn); 911 mutex_lock(&dev->list_mutex); 912 } 913 } 914 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 915 "has been finished.\n", dev->name); 916 mutex_unlock(&dev->list_mutex); 917 mutex_unlock(&dev->mutex); 918 } 919 mutex_unlock(&w1_mlock); 920 } 921 922 void w1_slave_found(struct w1_master *dev, u64 rn) 923 { 924 struct w1_slave *sl; 925 struct w1_reg_num *tmp; 926 u64 rn_le = cpu_to_le64(rn); 927 928 atomic_inc(&dev->refcnt); 929 930 tmp = (struct w1_reg_num *) &rn; 931 932 sl = w1_slave_search_device(dev, tmp); 933 if (sl) { 934 set_bit(W1_SLAVE_ACTIVE, &sl->flags); 935 } else { 936 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7)) 937 w1_attach_slave_device(dev, tmp); 938 } 939 940 atomic_dec(&dev->refcnt); 941 } 942 943 /** 944 * w1_search() - Performs a ROM Search & registers any devices found. 945 * @dev: The master device to search 946 * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH 947 * to return only devices in the alarmed state 948 * @cb: Function to call when a device is found 949 * 950 * The 1-wire search is a simple binary tree search. 951 * For each bit of the address, we read two bits and write one bit. 952 * The bit written will put to sleep all devies that don't match that bit. 953 * When the two reads differ, the direction choice is obvious. 954 * When both bits are 0, we must choose a path to take. 955 * When we can scan all 64 bits without having to choose a path, we are done. 956 * 957 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com 958 * 959 */ 960 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) 961 { 962 u64 last_rn, rn, tmp64; 963 int i, slave_count = 0; 964 int last_zero, last_device; 965 int search_bit, desc_bit; 966 u8 triplet_ret = 0; 967 968 search_bit = 0; 969 rn = dev->search_id; 970 last_rn = 0; 971 last_device = 0; 972 last_zero = -1; 973 974 desc_bit = 64; 975 976 while ( !last_device && (slave_count++ < dev->max_slave_count) ) { 977 last_rn = rn; 978 rn = 0; 979 980 /* 981 * Reset bus and all 1-wire device state machines 982 * so they can respond to our requests. 983 * 984 * Return 0 - device(s) present, 1 - no devices present. 985 */ 986 mutex_lock(&dev->bus_mutex); 987 if (w1_reset_bus(dev)) { 988 mutex_unlock(&dev->bus_mutex); 989 dev_dbg(&dev->dev, "No devices present on the wire.\n"); 990 break; 991 } 992 993 /* Do fast search on single slave bus */ 994 if (dev->max_slave_count == 1) { 995 int rv; 996 w1_write_8(dev, W1_READ_ROM); 997 rv = w1_read_block(dev, (u8 *)&rn, 8); 998 mutex_unlock(&dev->bus_mutex); 999 1000 if (rv == 8 && rn) 1001 cb(dev, rn); 1002 1003 break; 1004 } 1005 1006 /* Start the search */ 1007 w1_write_8(dev, search_type); 1008 for (i = 0; i < 64; ++i) { 1009 /* Determine the direction/search bit */ 1010 if (i == desc_bit) 1011 search_bit = 1; /* took the 0 path last time, so take the 1 path */ 1012 else if (i > desc_bit) 1013 search_bit = 0; /* take the 0 path on the next branch */ 1014 else 1015 search_bit = ((last_rn >> i) & 0x1); 1016 1017 /* Read two bits and write one bit */ 1018 triplet_ret = w1_triplet(dev, search_bit); 1019 1020 /* quit if no device responded */ 1021 if ( (triplet_ret & 0x03) == 0x03 ) 1022 break; 1023 1024 /* If both directions were valid, and we took the 0 path... */ 1025 if (triplet_ret == 0) 1026 last_zero = i; 1027 1028 /* extract the direction taken & update the device number */ 1029 tmp64 = (triplet_ret >> 2); 1030 rn |= (tmp64 << i); 1031 1032 if (test_bit(W1_ABORT_SEARCH, &dev->flags)) { 1033 mutex_unlock(&dev->bus_mutex); 1034 dev_dbg(&dev->dev, "Abort w1_search\n"); 1035 return; 1036 } 1037 } 1038 mutex_unlock(&dev->bus_mutex); 1039 1040 if ( (triplet_ret & 0x03) != 0x03 ) { 1041 if ((desc_bit == last_zero) || (last_zero < 0)) { 1042 last_device = 1; 1043 dev->search_id = 0; 1044 } else { 1045 dev->search_id = rn; 1046 } 1047 desc_bit = last_zero; 1048 cb(dev, rn); 1049 } 1050 1051 if (!last_device && slave_count == dev->max_slave_count && 1052 !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) { 1053 /* Only max_slave_count will be scanned in a search, 1054 * but it will start where it left off next search 1055 * until all ids are identified and then it will start 1056 * over. A continued search will report the previous 1057 * last id as the first id (provided it is still on the 1058 * bus). 1059 */ 1060 dev_info(&dev->dev, "%s: max_slave_count %d reached, " 1061 "will continue next search.\n", __func__, 1062 dev->max_slave_count); 1063 set_bit(W1_WARN_MAX_COUNT, &dev->flags); 1064 } 1065 } 1066 } 1067 1068 void w1_search_process_cb(struct w1_master *dev, u8 search_type, 1069 w1_slave_found_callback cb) 1070 { 1071 struct w1_slave *sl, *sln; 1072 1073 mutex_lock(&dev->list_mutex); 1074 list_for_each_entry(sl, &dev->slist, w1_slave_entry) 1075 clear_bit(W1_SLAVE_ACTIVE, &sl->flags); 1076 mutex_unlock(&dev->list_mutex); 1077 1078 w1_search_devices(dev, search_type, cb); 1079 1080 mutex_lock(&dev->list_mutex); 1081 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 1082 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) { 1083 mutex_unlock(&dev->list_mutex); 1084 w1_slave_detach(sl); 1085 mutex_lock(&dev->list_mutex); 1086 } 1087 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags)) 1088 sl->ttl = dev->slave_ttl; 1089 } 1090 mutex_unlock(&dev->list_mutex); 1091 1092 if (dev->search_count > 0) 1093 dev->search_count--; 1094 } 1095 1096 static void w1_search_process(struct w1_master *dev, u8 search_type) 1097 { 1098 w1_search_process_cb(dev, search_type, w1_slave_found); 1099 } 1100 1101 /** 1102 * w1_process_callbacks() - execute each dev->async_list callback entry 1103 * @dev: w1_master device 1104 * 1105 * The w1 master list_mutex must be held. 1106 * 1107 * Return: 1 if there were commands to executed 0 otherwise 1108 */ 1109 int w1_process_callbacks(struct w1_master *dev) 1110 { 1111 int ret = 0; 1112 struct w1_async_cmd *async_cmd, *async_n; 1113 1114 /* The list can be added to in another thread, loop until it is empty */ 1115 while (!list_empty(&dev->async_list)) { 1116 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list, 1117 async_entry) { 1118 /* drop the lock, if it is a search it can take a long 1119 * time */ 1120 mutex_unlock(&dev->list_mutex); 1121 async_cmd->cb(dev, async_cmd); 1122 ret = 1; 1123 mutex_lock(&dev->list_mutex); 1124 } 1125 } 1126 return ret; 1127 } 1128 1129 int w1_process(void *data) 1130 { 1131 struct w1_master *dev = (struct w1_master *) data; 1132 /* As long as w1_timeout is only set by a module parameter the sleep 1133 * time can be calculated in jiffies once. 1134 */ 1135 const unsigned long jtime = 1136 usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us); 1137 /* remainder if it woke up early */ 1138 unsigned long jremain = 0; 1139 1140 for (;;) { 1141 1142 if (!jremain && dev->search_count) { 1143 mutex_lock(&dev->mutex); 1144 w1_search_process(dev, W1_SEARCH); 1145 mutex_unlock(&dev->mutex); 1146 } 1147 1148 mutex_lock(&dev->list_mutex); 1149 /* Note, w1_process_callback drops the lock while processing, 1150 * but locks it again before returning. 1151 */ 1152 if (!w1_process_callbacks(dev) && jremain) { 1153 /* a wake up is either to stop the thread, process 1154 * callbacks, or search, it isn't process callbacks, so 1155 * schedule a search. 1156 */ 1157 jremain = 1; 1158 } 1159 1160 __set_current_state(TASK_INTERRUPTIBLE); 1161 1162 /* hold list_mutex until after interruptible to prevent loosing 1163 * the wakeup signal when async_cmd is added. 1164 */ 1165 mutex_unlock(&dev->list_mutex); 1166 1167 if (kthread_should_stop()) 1168 break; 1169 1170 /* Only sleep when the search is active. */ 1171 if (dev->search_count) { 1172 if (!jremain) 1173 jremain = jtime; 1174 jremain = schedule_timeout(jremain); 1175 } 1176 else 1177 schedule(); 1178 } 1179 1180 atomic_dec(&dev->refcnt); 1181 1182 return 0; 1183 } 1184 1185 static int __init w1_init(void) 1186 { 1187 int retval; 1188 1189 pr_info("Driver for 1-wire Dallas network protocol.\n"); 1190 1191 w1_init_netlink(); 1192 1193 retval = bus_register(&w1_bus_type); 1194 if (retval) { 1195 pr_err("Failed to register bus. err=%d.\n", retval); 1196 goto err_out_exit_init; 1197 } 1198 1199 retval = driver_register(&w1_master_driver); 1200 if (retval) { 1201 pr_err("Failed to register master driver. err=%d.\n", 1202 retval); 1203 goto err_out_bus_unregister; 1204 } 1205 1206 retval = driver_register(&w1_slave_driver); 1207 if (retval) { 1208 pr_err("Failed to register slave driver. err=%d.\n", 1209 retval); 1210 goto err_out_master_unregister; 1211 } 1212 1213 return 0; 1214 1215 #if 0 1216 /* For undoing the slave register if there was a step after it. */ 1217 err_out_slave_unregister: 1218 driver_unregister(&w1_slave_driver); 1219 #endif 1220 1221 err_out_master_unregister: 1222 driver_unregister(&w1_master_driver); 1223 1224 err_out_bus_unregister: 1225 bus_unregister(&w1_bus_type); 1226 1227 err_out_exit_init: 1228 return retval; 1229 } 1230 1231 static void __exit w1_fini(void) 1232 { 1233 struct w1_master *dev; 1234 1235 /* Set netlink removal messages and some cleanup */ 1236 list_for_each_entry(dev, &w1_masters, w1_master_entry) 1237 __w1_remove_master_device(dev); 1238 1239 w1_fini_netlink(); 1240 1241 driver_unregister(&w1_slave_driver); 1242 driver_unregister(&w1_master_driver); 1243 bus_unregister(&w1_bus_type); 1244 } 1245 1246 module_init(w1_init); 1247 module_exit(w1_fini); 1248 1249 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); 1250 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); 1251 MODULE_LICENSE("GPL"); 1252