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 29 #include <linux/atomic.h> 30 31 #include "w1_internal.h" 32 #include "w1_netlink.h" 33 34 #define W1_FAMILY_DEFAULT 0 35 36 static int w1_timeout = 10; 37 module_param_named(timeout, w1_timeout, int, 0); 38 MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches"); 39 40 static int w1_timeout_us = 0; 41 module_param_named(timeout_us, w1_timeout_us, int, 0); 42 MODULE_PARM_DESC(timeout_us, 43 "time in microseconds between automatic slave searches"); 44 45 /* A search stops when w1_max_slave_count devices have been found in that 46 * search. The next search will start over and detect the same set of devices 47 * on a static 1-wire bus. Memory is not allocated based on this number, just 48 * on the number of devices known to the kernel. Having a high number does not 49 * consume additional resources. As a special case, if there is only one 50 * device on the network and w1_max_slave_count is set to 1, the device id can 51 * be read directly skipping the normal slower search process. 52 */ 53 int w1_max_slave_count = 64; 54 module_param_named(max_slave_count, w1_max_slave_count, int, 0); 55 MODULE_PARM_DESC(max_slave_count, 56 "maximum number of slaves detected in a search"); 57 58 int w1_max_slave_ttl = 10; 59 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); 60 MODULE_PARM_DESC(slave_ttl, 61 "Number of searches not seeing a slave before it will be removed"); 62 63 DEFINE_MUTEX(w1_mlock); 64 LIST_HEAD(w1_masters); 65 66 static int w1_master_match(struct device *dev, struct device_driver *drv) 67 { 68 return 1; 69 } 70 71 static int w1_master_probe(struct device *dev) 72 { 73 return -ENODEV; 74 } 75 76 static void w1_master_release(struct device *dev) 77 { 78 struct w1_master *md = dev_to_w1_master(dev); 79 80 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); 81 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 82 kfree(md); 83 } 84 85 static void w1_slave_release(struct device *dev) 86 { 87 struct w1_slave *sl = dev_to_w1_slave(dev); 88 89 dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl); 90 91 w1_family_put(sl->family); 92 sl->master->slave_count--; 93 } 94 95 static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) 96 { 97 struct w1_slave *sl = dev_to_w1_slave(dev); 98 99 return sprintf(buf, "%s\n", sl->name); 100 } 101 static DEVICE_ATTR_RO(name); 102 103 static ssize_t id_show(struct device *dev, 104 struct device_attribute *attr, char *buf) 105 { 106 struct w1_slave *sl = dev_to_w1_slave(dev); 107 ssize_t count = sizeof(sl->reg_num); 108 109 memcpy(buf, (u8 *)&sl->reg_num, count); 110 return count; 111 } 112 static DEVICE_ATTR_RO(id); 113 114 static struct attribute *w1_slave_attrs[] = { 115 &dev_attr_name.attr, 116 &dev_attr_id.attr, 117 NULL, 118 }; 119 ATTRIBUTE_GROUPS(w1_slave); 120 121 /* Default family */ 122 123 static ssize_t rw_write(struct file *filp, struct kobject *kobj, 124 struct bin_attribute *bin_attr, char *buf, loff_t off, 125 size_t count) 126 { 127 struct w1_slave *sl = kobj_to_w1_slave(kobj); 128 129 mutex_lock(&sl->master->mutex); 130 if (w1_reset_select_slave(sl)) { 131 count = 0; 132 goto out_up; 133 } 134 135 w1_write_block(sl->master, buf, count); 136 137 out_up: 138 mutex_unlock(&sl->master->mutex); 139 return count; 140 } 141 142 static ssize_t rw_read(struct file *filp, struct kobject *kobj, 143 struct bin_attribute *bin_attr, char *buf, loff_t off, 144 size_t count) 145 { 146 struct w1_slave *sl = kobj_to_w1_slave(kobj); 147 148 mutex_lock(&sl->master->mutex); 149 w1_read_block(sl->master, buf, count); 150 mutex_unlock(&sl->master->mutex); 151 return count; 152 } 153 154 static BIN_ATTR_RW(rw, PAGE_SIZE); 155 156 static struct bin_attribute *w1_slave_bin_attrs[] = { 157 &bin_attr_rw, 158 NULL, 159 }; 160 161 static const struct attribute_group w1_slave_default_group = { 162 .bin_attrs = w1_slave_bin_attrs, 163 }; 164 165 static const struct attribute_group *w1_slave_default_groups[] = { 166 &w1_slave_default_group, 167 NULL, 168 }; 169 170 static struct w1_family_ops w1_default_fops = { 171 .groups = w1_slave_default_groups, 172 }; 173 174 static struct w1_family w1_default_family = { 175 .fops = &w1_default_fops, 176 }; 177 178 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env); 179 180 static struct bus_type w1_bus_type = { 181 .name = "w1", 182 .match = w1_master_match, 183 .uevent = w1_uevent, 184 }; 185 186 struct device_driver w1_master_driver = { 187 .name = "w1_master_driver", 188 .bus = &w1_bus_type, 189 .probe = w1_master_probe, 190 }; 191 192 struct device w1_master_device = { 193 .parent = NULL, 194 .bus = &w1_bus_type, 195 .init_name = "w1 bus master", 196 .driver = &w1_master_driver, 197 .release = &w1_master_release 198 }; 199 200 static struct device_driver w1_slave_driver = { 201 .name = "w1_slave_driver", 202 .bus = &w1_bus_type, 203 }; 204 205 #if 0 206 struct device w1_slave_device = { 207 .parent = NULL, 208 .bus = &w1_bus_type, 209 .init_name = "w1 bus slave", 210 .driver = &w1_slave_driver, 211 .release = &w1_slave_release 212 }; 213 #endif /* 0 */ 214 215 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) 216 { 217 struct w1_master *md = dev_to_w1_master(dev); 218 ssize_t count; 219 220 mutex_lock(&md->mutex); 221 count = sprintf(buf, "%s\n", md->name); 222 mutex_unlock(&md->mutex); 223 224 return count; 225 } 226 227 static ssize_t w1_master_attribute_store_search(struct device * dev, 228 struct device_attribute *attr, 229 const char * buf, size_t count) 230 { 231 long tmp; 232 struct w1_master *md = dev_to_w1_master(dev); 233 int ret; 234 235 ret = kstrtol(buf, 0, &tmp); 236 if (ret) 237 return ret; 238 239 mutex_lock(&md->mutex); 240 md->search_count = tmp; 241 mutex_unlock(&md->mutex); 242 /* Only wake if it is going to be searching. */ 243 if (tmp) 244 wake_up_process(md->thread); 245 246 return count; 247 } 248 249 static ssize_t w1_master_attribute_show_search(struct device *dev, 250 struct device_attribute *attr, 251 char *buf) 252 { 253 struct w1_master *md = dev_to_w1_master(dev); 254 ssize_t count; 255 256 mutex_lock(&md->mutex); 257 count = sprintf(buf, "%d\n", md->search_count); 258 mutex_unlock(&md->mutex); 259 260 return count; 261 } 262 263 static ssize_t w1_master_attribute_store_pullup(struct device *dev, 264 struct device_attribute *attr, 265 const char *buf, size_t count) 266 { 267 long tmp; 268 struct w1_master *md = dev_to_w1_master(dev); 269 int ret; 270 271 ret = kstrtol(buf, 0, &tmp); 272 if (ret) 273 return ret; 274 275 mutex_lock(&md->mutex); 276 md->enable_pullup = tmp; 277 mutex_unlock(&md->mutex); 278 279 return count; 280 } 281 282 static ssize_t w1_master_attribute_show_pullup(struct device *dev, 283 struct device_attribute *attr, 284 char *buf) 285 { 286 struct w1_master *md = dev_to_w1_master(dev); 287 ssize_t count; 288 289 mutex_lock(&md->mutex); 290 count = sprintf(buf, "%d\n", md->enable_pullup); 291 mutex_unlock(&md->mutex); 292 293 return count; 294 } 295 296 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) 297 { 298 struct w1_master *md = dev_to_w1_master(dev); 299 ssize_t count; 300 301 mutex_lock(&md->mutex); 302 count = sprintf(buf, "0x%p\n", md->bus_master); 303 mutex_unlock(&md->mutex); 304 return count; 305 } 306 307 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) 308 { 309 ssize_t count; 310 count = sprintf(buf, "%d\n", w1_timeout); 311 return count; 312 } 313 314 static ssize_t w1_master_attribute_show_timeout_us(struct device *dev, 315 struct device_attribute *attr, char *buf) 316 { 317 ssize_t count; 318 count = sprintf(buf, "%d\n", w1_timeout_us); 319 return count; 320 } 321 322 static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev, 323 struct device_attribute *attr, const char *buf, size_t count) 324 { 325 int tmp; 326 struct w1_master *md = dev_to_w1_master(dev); 327 328 if (kstrtoint(buf, 0, &tmp) || tmp < 1) 329 return -EINVAL; 330 331 mutex_lock(&md->mutex); 332 md->max_slave_count = tmp; 333 /* allow each time the max_slave_count is updated */ 334 clear_bit(W1_WARN_MAX_COUNT, &md->flags); 335 mutex_unlock(&md->mutex); 336 337 return count; 338 } 339 340 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 341 { 342 struct w1_master *md = dev_to_w1_master(dev); 343 ssize_t count; 344 345 mutex_lock(&md->mutex); 346 count = sprintf(buf, "%d\n", md->max_slave_count); 347 mutex_unlock(&md->mutex); 348 return count; 349 } 350 351 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) 352 { 353 struct w1_master *md = dev_to_w1_master(dev); 354 ssize_t count; 355 356 mutex_lock(&md->mutex); 357 count = sprintf(buf, "%lu\n", md->attempts); 358 mutex_unlock(&md->mutex); 359 return count; 360 } 361 362 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 363 { 364 struct w1_master *md = dev_to_w1_master(dev); 365 ssize_t count; 366 367 mutex_lock(&md->mutex); 368 count = sprintf(buf, "%d\n", md->slave_count); 369 mutex_unlock(&md->mutex); 370 return count; 371 } 372 373 static ssize_t w1_master_attribute_show_slaves(struct device *dev, 374 struct device_attribute *attr, char *buf) 375 { 376 struct w1_master *md = dev_to_w1_master(dev); 377 int c = PAGE_SIZE; 378 struct list_head *ent, *n; 379 struct w1_slave *sl = NULL; 380 381 mutex_lock(&md->list_mutex); 382 383 list_for_each_safe(ent, n, &md->slist) { 384 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 385 386 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); 387 } 388 if (!sl) 389 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); 390 391 mutex_unlock(&md->list_mutex); 392 393 return PAGE_SIZE - c; 394 } 395 396 static ssize_t w1_master_attribute_show_add(struct device *dev, 397 struct device_attribute *attr, char *buf) 398 { 399 int c = PAGE_SIZE; 400 c -= snprintf(buf+PAGE_SIZE - c, c, 401 "write device id xx-xxxxxxxxxxxx to add slave\n"); 402 return PAGE_SIZE - c; 403 } 404 405 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count, 406 struct w1_reg_num *rn) 407 { 408 unsigned int family; 409 unsigned long long id; 410 int i; 411 u64 rn64_le; 412 413 /* The CRC value isn't read from the user because the sysfs directory 414 * doesn't include it and most messages from the bus search don't 415 * print it either. It would be unreasonable for the user to then 416 * provide it. 417 */ 418 const char *error_msg = "bad slave string format, expecting " 419 "ff-dddddddddddd\n"; 420 421 if (buf[2] != '-') { 422 dev_err(dev, "%s", error_msg); 423 return -EINVAL; 424 } 425 i = sscanf(buf, "%02x-%012llx", &family, &id); 426 if (i != 2) { 427 dev_err(dev, "%s", error_msg); 428 return -EINVAL; 429 } 430 rn->family = family; 431 rn->id = id; 432 433 rn64_le = cpu_to_le64(*(u64 *)rn); 434 rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7); 435 436 #if 0 437 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n", 438 rn->family, (unsigned long long)rn->id, rn->crc); 439 #endif 440 441 return 0; 442 } 443 444 /* Searches the slaves in the w1_master and returns a pointer or NULL. 445 * Note: must not hold list_mutex 446 */ 447 struct w1_slave *w1_slave_search_device(struct w1_master *dev, 448 struct w1_reg_num *rn) 449 { 450 struct w1_slave *sl; 451 mutex_lock(&dev->list_mutex); 452 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 453 if (sl->reg_num.family == rn->family && 454 sl->reg_num.id == rn->id && 455 sl->reg_num.crc == rn->crc) { 456 mutex_unlock(&dev->list_mutex); 457 return sl; 458 } 459 } 460 mutex_unlock(&dev->list_mutex); 461 return NULL; 462 } 463 464 static ssize_t w1_master_attribute_store_add(struct device *dev, 465 struct device_attribute *attr, 466 const char *buf, size_t count) 467 { 468 struct w1_master *md = dev_to_w1_master(dev); 469 struct w1_reg_num rn; 470 struct w1_slave *sl; 471 ssize_t result = count; 472 473 if (w1_atoreg_num(dev, buf, count, &rn)) 474 return -EINVAL; 475 476 mutex_lock(&md->mutex); 477 sl = w1_slave_search_device(md, &rn); 478 /* It would be nice to do a targeted search one the one-wire bus 479 * for the new device to see if it is out there or not. But the 480 * current search doesn't support that. 481 */ 482 if (sl) { 483 dev_info(dev, "Device %s already exists\n", sl->name); 484 result = -EINVAL; 485 } else { 486 w1_attach_slave_device(md, &rn); 487 } 488 mutex_unlock(&md->mutex); 489 490 return result; 491 } 492 493 static ssize_t w1_master_attribute_show_remove(struct device *dev, 494 struct device_attribute *attr, char *buf) 495 { 496 int c = PAGE_SIZE; 497 c -= snprintf(buf+PAGE_SIZE - c, c, 498 "write device id xx-xxxxxxxxxxxx to remove slave\n"); 499 return PAGE_SIZE - c; 500 } 501 502 static ssize_t w1_master_attribute_store_remove(struct device *dev, 503 struct device_attribute *attr, 504 const char *buf, size_t count) 505 { 506 struct w1_master *md = dev_to_w1_master(dev); 507 struct w1_reg_num rn; 508 struct w1_slave *sl; 509 ssize_t result = count; 510 511 if (w1_atoreg_num(dev, buf, count, &rn)) 512 return -EINVAL; 513 514 mutex_lock(&md->mutex); 515 sl = w1_slave_search_device(md, &rn); 516 if (sl) { 517 result = w1_slave_detach(sl); 518 /* refcnt 0 means it was detached in the call */ 519 if (result == 0) 520 result = count; 521 } else { 522 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family, 523 (unsigned long long)rn.id); 524 result = -EINVAL; 525 } 526 mutex_unlock(&md->mutex); 527 528 return result; 529 } 530 531 #define W1_MASTER_ATTR_RO(_name, _mode) \ 532 struct device_attribute w1_master_attribute_##_name = \ 533 __ATTR(w1_master_##_name, _mode, \ 534 w1_master_attribute_show_##_name, NULL) 535 536 #define W1_MASTER_ATTR_RW(_name, _mode) \ 537 struct device_attribute w1_master_attribute_##_name = \ 538 __ATTR(w1_master_##_name, _mode, \ 539 w1_master_attribute_show_##_name, \ 540 w1_master_attribute_store_##_name) 541 542 static W1_MASTER_ATTR_RO(name, S_IRUGO); 543 static W1_MASTER_ATTR_RO(slaves, S_IRUGO); 544 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); 545 static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP); 546 static W1_MASTER_ATTR_RO(attempts, S_IRUGO); 547 static W1_MASTER_ATTR_RO(timeout, S_IRUGO); 548 static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO); 549 static W1_MASTER_ATTR_RO(pointer, S_IRUGO); 550 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP); 551 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP); 552 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP); 553 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP); 554 555 static struct attribute *w1_master_default_attrs[] = { 556 &w1_master_attribute_name.attr, 557 &w1_master_attribute_slaves.attr, 558 &w1_master_attribute_slave_count.attr, 559 &w1_master_attribute_max_slave_count.attr, 560 &w1_master_attribute_attempts.attr, 561 &w1_master_attribute_timeout.attr, 562 &w1_master_attribute_timeout_us.attr, 563 &w1_master_attribute_pointer.attr, 564 &w1_master_attribute_search.attr, 565 &w1_master_attribute_pullup.attr, 566 &w1_master_attribute_add.attr, 567 &w1_master_attribute_remove.attr, 568 NULL 569 }; 570 571 static struct attribute_group w1_master_defattr_group = { 572 .attrs = w1_master_default_attrs, 573 }; 574 575 int w1_create_master_attributes(struct w1_master *master) 576 { 577 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); 578 } 579 580 void w1_destroy_master_attributes(struct w1_master *master) 581 { 582 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); 583 } 584 585 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env) 586 { 587 struct w1_master *md = NULL; 588 struct w1_slave *sl = NULL; 589 char *event_owner, *name; 590 int err = 0; 591 592 if (dev->driver == &w1_master_driver) { 593 md = container_of(dev, struct w1_master, dev); 594 event_owner = "master"; 595 name = md->name; 596 } else if (dev->driver == &w1_slave_driver) { 597 sl = container_of(dev, struct w1_slave, dev); 598 event_owner = "slave"; 599 name = sl->name; 600 } else { 601 dev_dbg(dev, "Unknown event.\n"); 602 return -EINVAL; 603 } 604 605 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", 606 event_owner, name, dev_name(dev)); 607 608 if (dev->driver != &w1_slave_driver || !sl) 609 goto end; 610 611 err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family); 612 if (err) 613 goto end; 614 615 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX", 616 (unsigned long long)sl->reg_num.id); 617 end: 618 return err; 619 } 620 621 static int w1_family_notify(unsigned long action, struct w1_slave *sl) 622 { 623 struct w1_family_ops *fops; 624 int err; 625 626 fops = sl->family->fops; 627 628 if (!fops) 629 return 0; 630 631 switch (action) { 632 case BUS_NOTIFY_ADD_DEVICE: 633 /* if the family driver needs to initialize something... */ 634 if (fops->add_slave) { 635 err = fops->add_slave(sl); 636 if (err < 0) { 637 dev_err(&sl->dev, 638 "add_slave() call failed. err=%d\n", 639 err); 640 return err; 641 } 642 } 643 if (fops->groups) { 644 err = sysfs_create_groups(&sl->dev.kobj, fops->groups); 645 if (err) { 646 dev_err(&sl->dev, 647 "sysfs group creation failed. err=%d\n", 648 err); 649 return err; 650 } 651 } 652 653 break; 654 case BUS_NOTIFY_DEL_DEVICE: 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; 673 674 dev_set_name(&sl->dev, "%02x-%012llx", 675 (unsigned int) sl->reg_num.family, 676 (unsigned long long) sl->reg_num.id); 677 snprintf(&sl->name[0], sizeof(sl->name), 678 "%02x-%012llx", 679 (unsigned int) sl->reg_num.family, 680 (unsigned long long) sl->reg_num.id); 681 682 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, 683 dev_name(&sl->dev), sl); 684 685 /* suppress for w1_family_notify before sending KOBJ_ADD */ 686 dev_set_uevent_suppress(&sl->dev, true); 687 688 err = device_register(&sl->dev); 689 if (err < 0) { 690 dev_err(&sl->dev, 691 "Device registration [%s] failed. err=%d\n", 692 dev_name(&sl->dev), err); 693 return err; 694 } 695 w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl); 696 697 dev_set_uevent_suppress(&sl->dev, false); 698 kobject_uevent(&sl->dev.kobj, KOBJ_ADD); 699 700 mutex_lock(&sl->master->list_mutex); 701 list_add_tail(&sl->w1_slave_entry, &sl->master->slist); 702 mutex_unlock(&sl->master->list_mutex); 703 704 return 0; 705 } 706 707 int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 708 { 709 struct w1_slave *sl; 710 struct w1_family *f; 711 int err; 712 struct w1_netlink_msg msg; 713 714 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL); 715 if (!sl) { 716 dev_err(&dev->dev, 717 "%s: failed to allocate new slave device.\n", 718 __func__); 719 return -ENOMEM; 720 } 721 722 723 sl->owner = THIS_MODULE; 724 sl->master = dev; 725 set_bit(W1_SLAVE_ACTIVE, &sl->flags); 726 727 memset(&msg, 0, sizeof(msg)); 728 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); 729 atomic_set(&sl->refcnt, 1); 730 atomic_inc(&sl->master->refcnt); 731 732 /* slave modules need to be loaded in a context with unlocked mutex */ 733 mutex_unlock(&dev->mutex); 734 request_module("w1-family-0x%02x", rn->family); 735 mutex_lock(&dev->mutex); 736 737 spin_lock(&w1_flock); 738 f = w1_family_registered(rn->family); 739 if (!f) { 740 f= &w1_default_family; 741 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", 742 rn->family, rn->family, 743 (unsigned long long)rn->id, rn->crc); 744 } 745 __w1_family_get(f); 746 spin_unlock(&w1_flock); 747 748 sl->family = f; 749 750 751 err = __w1_attach_slave_device(sl); 752 if (err < 0) { 753 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, 754 sl->name); 755 w1_family_put(sl->family); 756 atomic_dec(&sl->master->refcnt); 757 kfree(sl); 758 return err; 759 } 760 761 sl->ttl = dev->slave_ttl; 762 dev->slave_count++; 763 764 memcpy(msg.id.id, rn, sizeof(msg.id)); 765 msg.type = W1_SLAVE_ADD; 766 w1_netlink_send(dev, &msg); 767 768 return 0; 769 } 770 771 int w1_unref_slave(struct w1_slave *sl) 772 { 773 struct w1_master *dev = sl->master; 774 int refcnt; 775 mutex_lock(&dev->list_mutex); 776 refcnt = atomic_sub_return(1, &sl->refcnt); 777 if (refcnt == 0) { 778 struct w1_netlink_msg msg; 779 780 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, 781 sl->name, sl); 782 783 list_del(&sl->w1_slave_entry); 784 785 memset(&msg, 0, sizeof(msg)); 786 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); 787 msg.type = W1_SLAVE_REMOVE; 788 w1_netlink_send(sl->master, &msg); 789 790 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl); 791 device_unregister(&sl->dev); 792 #ifdef DEBUG 793 memset(sl, 0, sizeof(*sl)); 794 #endif 795 kfree(sl); 796 } 797 atomic_dec(&dev->refcnt); 798 mutex_unlock(&dev->list_mutex); 799 return refcnt; 800 } 801 802 int w1_slave_detach(struct w1_slave *sl) 803 { 804 /* Only detach a slave once as it decreases the refcnt each time. */ 805 int destroy_now; 806 mutex_lock(&sl->master->list_mutex); 807 destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags); 808 set_bit(W1_SLAVE_DETACH, &sl->flags); 809 mutex_unlock(&sl->master->list_mutex); 810 811 if (destroy_now) 812 destroy_now = !w1_unref_slave(sl); 813 return destroy_now ? 0 : -EBUSY; 814 } 815 816 struct w1_master *w1_search_master_id(u32 id) 817 { 818 struct w1_master *dev; 819 int found = 0; 820 821 mutex_lock(&w1_mlock); 822 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 823 if (dev->id == id) { 824 found = 1; 825 atomic_inc(&dev->refcnt); 826 break; 827 } 828 } 829 mutex_unlock(&w1_mlock); 830 831 return (found)?dev:NULL; 832 } 833 834 struct w1_slave *w1_search_slave(struct w1_reg_num *id) 835 { 836 struct w1_master *dev; 837 struct w1_slave *sl = NULL; 838 int found = 0; 839 840 mutex_lock(&w1_mlock); 841 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 842 mutex_lock(&dev->list_mutex); 843 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 844 if (sl->reg_num.family == id->family && 845 sl->reg_num.id == id->id && 846 sl->reg_num.crc == id->crc) { 847 found = 1; 848 atomic_inc(&dev->refcnt); 849 atomic_inc(&sl->refcnt); 850 break; 851 } 852 } 853 mutex_unlock(&dev->list_mutex); 854 855 if (found) 856 break; 857 } 858 mutex_unlock(&w1_mlock); 859 860 return (found)?sl:NULL; 861 } 862 863 void w1_reconnect_slaves(struct w1_family *f, int attach) 864 { 865 struct w1_slave *sl, *sln; 866 struct w1_master *dev; 867 868 mutex_lock(&w1_mlock); 869 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 870 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 871 "for family %02x.\n", dev->name, f->fid); 872 mutex_lock(&dev->mutex); 873 mutex_lock(&dev->list_mutex); 874 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 875 /* If it is a new family, slaves with the default 876 * family driver and are that family will be 877 * connected. If the family is going away, devices 878 * matching that family are reconneced. 879 */ 880 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT 881 && sl->reg_num.family == f->fid) || 882 (!attach && sl->family->fid == f->fid)) { 883 struct w1_reg_num rn; 884 885 mutex_unlock(&dev->list_mutex); 886 memcpy(&rn, &sl->reg_num, sizeof(rn)); 887 /* If it was already in use let the automatic 888 * scan pick it up again later. 889 */ 890 if (!w1_slave_detach(sl)) 891 w1_attach_slave_device(dev, &rn); 892 mutex_lock(&dev->list_mutex); 893 } 894 } 895 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 896 "has been finished.\n", dev->name); 897 mutex_unlock(&dev->list_mutex); 898 mutex_unlock(&dev->mutex); 899 } 900 mutex_unlock(&w1_mlock); 901 } 902 903 void w1_slave_found(struct w1_master *dev, u64 rn) 904 { 905 struct w1_slave *sl; 906 struct w1_reg_num *tmp; 907 u64 rn_le = cpu_to_le64(rn); 908 909 atomic_inc(&dev->refcnt); 910 911 tmp = (struct w1_reg_num *) &rn; 912 913 sl = w1_slave_search_device(dev, tmp); 914 if (sl) { 915 set_bit(W1_SLAVE_ACTIVE, &sl->flags); 916 } else { 917 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7)) 918 w1_attach_slave_device(dev, tmp); 919 } 920 921 atomic_dec(&dev->refcnt); 922 } 923 924 /** 925 * w1_search() - Performs a ROM Search & registers any devices found. 926 * @dev: The master device to search 927 * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH 928 * to return only devices in the alarmed state 929 * @cb: Function to call when a device is found 930 * 931 * The 1-wire search is a simple binary tree search. 932 * For each bit of the address, we read two bits and write one bit. 933 * The bit written will put to sleep all devies that don't match that bit. 934 * When the two reads differ, the direction choice is obvious. 935 * When both bits are 0, we must choose a path to take. 936 * When we can scan all 64 bits without having to choose a path, we are done. 937 * 938 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com 939 * 940 */ 941 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) 942 { 943 u64 last_rn, rn, tmp64; 944 int i, slave_count = 0; 945 int last_zero, last_device; 946 int search_bit, desc_bit; 947 u8 triplet_ret = 0; 948 949 search_bit = 0; 950 rn = dev->search_id; 951 last_rn = 0; 952 last_device = 0; 953 last_zero = -1; 954 955 desc_bit = 64; 956 957 while ( !last_device && (slave_count++ < dev->max_slave_count) ) { 958 last_rn = rn; 959 rn = 0; 960 961 /* 962 * Reset bus and all 1-wire device state machines 963 * so they can respond to our requests. 964 * 965 * Return 0 - device(s) present, 1 - no devices present. 966 */ 967 mutex_lock(&dev->bus_mutex); 968 if (w1_reset_bus(dev)) { 969 mutex_unlock(&dev->bus_mutex); 970 dev_dbg(&dev->dev, "No devices present on the wire.\n"); 971 break; 972 } 973 974 /* Do fast search on single slave bus */ 975 if (dev->max_slave_count == 1) { 976 int rv; 977 w1_write_8(dev, W1_READ_ROM); 978 rv = w1_read_block(dev, (u8 *)&rn, 8); 979 mutex_unlock(&dev->bus_mutex); 980 981 if (rv == 8 && rn) 982 cb(dev, rn); 983 984 break; 985 } 986 987 /* Start the search */ 988 w1_write_8(dev, search_type); 989 for (i = 0; i < 64; ++i) { 990 /* Determine the direction/search bit */ 991 if (i == desc_bit) 992 search_bit = 1; /* took the 0 path last time, so take the 1 path */ 993 else if (i > desc_bit) 994 search_bit = 0; /* take the 0 path on the next branch */ 995 else 996 search_bit = ((last_rn >> i) & 0x1); 997 998 /* Read two bits and write one bit */ 999 triplet_ret = w1_triplet(dev, search_bit); 1000 1001 /* quit if no device responded */ 1002 if ( (triplet_ret & 0x03) == 0x03 ) 1003 break; 1004 1005 /* If both directions were valid, and we took the 0 path... */ 1006 if (triplet_ret == 0) 1007 last_zero = i; 1008 1009 /* extract the direction taken & update the device number */ 1010 tmp64 = (triplet_ret >> 2); 1011 rn |= (tmp64 << i); 1012 1013 if (test_bit(W1_ABORT_SEARCH, &dev->flags)) { 1014 mutex_unlock(&dev->bus_mutex); 1015 dev_dbg(&dev->dev, "Abort w1_search\n"); 1016 return; 1017 } 1018 } 1019 mutex_unlock(&dev->bus_mutex); 1020 1021 if ( (triplet_ret & 0x03) != 0x03 ) { 1022 if ((desc_bit == last_zero) || (last_zero < 0)) { 1023 last_device = 1; 1024 dev->search_id = 0; 1025 } else { 1026 dev->search_id = rn; 1027 } 1028 desc_bit = last_zero; 1029 cb(dev, rn); 1030 } 1031 1032 if (!last_device && slave_count == dev->max_slave_count && 1033 !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) { 1034 /* Only max_slave_count will be scanned in a search, 1035 * but it will start where it left off next search 1036 * until all ids are identified and then it will start 1037 * over. A continued search will report the previous 1038 * last id as the first id (provided it is still on the 1039 * bus). 1040 */ 1041 dev_info(&dev->dev, "%s: max_slave_count %d reached, " 1042 "will continue next search.\n", __func__, 1043 dev->max_slave_count); 1044 set_bit(W1_WARN_MAX_COUNT, &dev->flags); 1045 } 1046 } 1047 } 1048 1049 void w1_search_process_cb(struct w1_master *dev, u8 search_type, 1050 w1_slave_found_callback cb) 1051 { 1052 struct w1_slave *sl, *sln; 1053 1054 mutex_lock(&dev->list_mutex); 1055 list_for_each_entry(sl, &dev->slist, w1_slave_entry) 1056 clear_bit(W1_SLAVE_ACTIVE, &sl->flags); 1057 mutex_unlock(&dev->list_mutex); 1058 1059 w1_search_devices(dev, search_type, cb); 1060 1061 mutex_lock(&dev->list_mutex); 1062 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 1063 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) { 1064 mutex_unlock(&dev->list_mutex); 1065 w1_slave_detach(sl); 1066 mutex_lock(&dev->list_mutex); 1067 } 1068 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags)) 1069 sl->ttl = dev->slave_ttl; 1070 } 1071 mutex_unlock(&dev->list_mutex); 1072 1073 if (dev->search_count > 0) 1074 dev->search_count--; 1075 } 1076 1077 static void w1_search_process(struct w1_master *dev, u8 search_type) 1078 { 1079 w1_search_process_cb(dev, search_type, w1_slave_found); 1080 } 1081 1082 /** 1083 * w1_process_callbacks() - execute each dev->async_list callback entry 1084 * @dev: w1_master device 1085 * 1086 * The w1 master list_mutex must be held. 1087 * 1088 * Return: 1 if there were commands to executed 0 otherwise 1089 */ 1090 int w1_process_callbacks(struct w1_master *dev) 1091 { 1092 int ret = 0; 1093 struct w1_async_cmd *async_cmd, *async_n; 1094 1095 /* The list can be added to in another thread, loop until it is empty */ 1096 while (!list_empty(&dev->async_list)) { 1097 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list, 1098 async_entry) { 1099 /* drop the lock, if it is a search it can take a long 1100 * time */ 1101 mutex_unlock(&dev->list_mutex); 1102 async_cmd->cb(dev, async_cmd); 1103 ret = 1; 1104 mutex_lock(&dev->list_mutex); 1105 } 1106 } 1107 return ret; 1108 } 1109 1110 int w1_process(void *data) 1111 { 1112 struct w1_master *dev = (struct w1_master *) data; 1113 /* As long as w1_timeout is only set by a module parameter the sleep 1114 * time can be calculated in jiffies once. 1115 */ 1116 const unsigned long jtime = 1117 usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us); 1118 /* remainder if it woke up early */ 1119 unsigned long jremain = 0; 1120 1121 for (;;) { 1122 1123 if (!jremain && dev->search_count) { 1124 mutex_lock(&dev->mutex); 1125 w1_search_process(dev, W1_SEARCH); 1126 mutex_unlock(&dev->mutex); 1127 } 1128 1129 mutex_lock(&dev->list_mutex); 1130 /* Note, w1_process_callback drops the lock while processing, 1131 * but locks it again before returning. 1132 */ 1133 if (!w1_process_callbacks(dev) && jremain) { 1134 /* a wake up is either to stop the thread, process 1135 * callbacks, or search, it isn't process callbacks, so 1136 * schedule a search. 1137 */ 1138 jremain = 1; 1139 } 1140 1141 __set_current_state(TASK_INTERRUPTIBLE); 1142 1143 /* hold list_mutex until after interruptible to prevent loosing 1144 * the wakeup signal when async_cmd is added. 1145 */ 1146 mutex_unlock(&dev->list_mutex); 1147 1148 if (kthread_should_stop()) 1149 break; 1150 1151 /* Only sleep when the search is active. */ 1152 if (dev->search_count) { 1153 if (!jremain) 1154 jremain = jtime; 1155 jremain = schedule_timeout(jremain); 1156 } 1157 else 1158 schedule(); 1159 } 1160 1161 atomic_dec(&dev->refcnt); 1162 1163 return 0; 1164 } 1165 1166 static int __init w1_init(void) 1167 { 1168 int retval; 1169 1170 pr_info("Driver for 1-wire Dallas network protocol.\n"); 1171 1172 w1_init_netlink(); 1173 1174 retval = bus_register(&w1_bus_type); 1175 if (retval) { 1176 pr_err("Failed to register bus. err=%d.\n", retval); 1177 goto err_out_exit_init; 1178 } 1179 1180 retval = driver_register(&w1_master_driver); 1181 if (retval) { 1182 pr_err("Failed to register master driver. err=%d.\n", 1183 retval); 1184 goto err_out_bus_unregister; 1185 } 1186 1187 retval = driver_register(&w1_slave_driver); 1188 if (retval) { 1189 pr_err("Failed to register slave driver. err=%d.\n", 1190 retval); 1191 goto err_out_master_unregister; 1192 } 1193 1194 return 0; 1195 1196 #if 0 1197 /* For undoing the slave register if there was a step after it. */ 1198 err_out_slave_unregister: 1199 driver_unregister(&w1_slave_driver); 1200 #endif 1201 1202 err_out_master_unregister: 1203 driver_unregister(&w1_master_driver); 1204 1205 err_out_bus_unregister: 1206 bus_unregister(&w1_bus_type); 1207 1208 err_out_exit_init: 1209 return retval; 1210 } 1211 1212 static void __exit w1_fini(void) 1213 { 1214 struct w1_master *dev; 1215 1216 /* Set netlink removal messages and some cleanup */ 1217 list_for_each_entry(dev, &w1_masters, w1_master_entry) 1218 __w1_remove_master_device(dev); 1219 1220 w1_fini_netlink(); 1221 1222 driver_unregister(&w1_slave_driver); 1223 driver_unregister(&w1_master_driver); 1224 bus_unregister(&w1_bus_type); 1225 } 1226 1227 module_init(w1_init); 1228 module_exit(w1_fini); 1229 1230 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); 1231 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); 1232 MODULE_LICENSE("GPL"); 1233