1 /* 2 * w1.c 3 * 4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> 5 * 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22 #include <linux/delay.h> 23 #include <linux/kernel.h> 24 #include <linux/module.h> 25 #include <linux/moduleparam.h> 26 #include <linux/list.h> 27 #include <linux/interrupt.h> 28 #include <linux/spinlock.h> 29 #include <linux/timer.h> 30 #include <linux/device.h> 31 #include <linux/slab.h> 32 #include <linux/sched.h> 33 #include <linux/kthread.h> 34 35 #include <asm/atomic.h> 36 37 #include "w1.h" 38 #include "w1_log.h" 39 #include "w1_int.h" 40 #include "w1_family.h" 41 #include "w1_netlink.h" 42 43 MODULE_LICENSE("GPL"); 44 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); 45 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); 46 47 static int w1_timeout = 10; 48 static int w1_control_timeout = 1; 49 int w1_max_slave_count = 10; 50 int w1_max_slave_ttl = 10; 51 52 module_param_named(timeout, w1_timeout, int, 0); 53 module_param_named(control_timeout, w1_control_timeout, int, 0); 54 module_param_named(max_slave_count, w1_max_slave_count, int, 0); 55 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); 56 57 DEFINE_MUTEX(w1_mlock); 58 LIST_HEAD(w1_masters); 59 60 static struct task_struct *w1_control_thread; 61 62 static int w1_master_match(struct device *dev, struct device_driver *drv) 63 { 64 return 1; 65 } 66 67 static int w1_master_probe(struct device *dev) 68 { 69 return -ENODEV; 70 } 71 72 static void w1_master_release(struct device *dev) 73 { 74 struct w1_master *md = dev_to_w1_master(dev); 75 76 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); 77 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 78 kfree(md); 79 } 80 81 static void w1_slave_release(struct device *dev) 82 { 83 struct w1_slave *sl = dev_to_w1_slave(dev); 84 85 printk("%s: Releasing %s.\n", __func__, sl->name); 86 87 while (atomic_read(&sl->refcnt)) { 88 printk("Waiting for %s to become free: refcnt=%d.\n", 89 sl->name, atomic_read(&sl->refcnt)); 90 if (msleep_interruptible(1000)) 91 flush_signals(current); 92 } 93 94 w1_family_put(sl->family); 95 sl->master->slave_count--; 96 97 complete(&sl->released); 98 } 99 100 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf) 101 { 102 struct w1_slave *sl = dev_to_w1_slave(dev); 103 104 return sprintf(buf, "%s\n", sl->name); 105 } 106 107 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count) 108 { 109 struct w1_slave *sl = kobj_to_w1_slave(kobj); 110 111 if (off > 8) { 112 count = 0; 113 } else { 114 if (off + count > 8) 115 count = 8 - off; 116 117 memcpy(buf, (u8 *)&sl->reg_num, count); 118 } 119 120 return count; 121 } 122 123 static struct device_attribute w1_slave_attr_name = 124 __ATTR(name, S_IRUGO, w1_slave_read_name, NULL); 125 126 static struct bin_attribute w1_slave_attr_bin_id = { 127 .attr = { 128 .name = "id", 129 .mode = S_IRUGO, 130 .owner = THIS_MODULE, 131 }, 132 .size = 8, 133 .read = w1_slave_read_id, 134 }; 135 136 /* Default family */ 137 138 static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count) 139 { 140 struct w1_slave *sl = kobj_to_w1_slave(kobj); 141 142 mutex_lock(&sl->master->mutex); 143 if (w1_reset_select_slave(sl)) { 144 count = 0; 145 goto out_up; 146 } 147 148 w1_write_block(sl->master, buf, count); 149 150 out_up: 151 mutex_unlock(&sl->master->mutex); 152 return count; 153 } 154 155 static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count) 156 { 157 struct w1_slave *sl = kobj_to_w1_slave(kobj); 158 159 mutex_lock(&sl->master->mutex); 160 w1_read_block(sl->master, buf, count); 161 mutex_unlock(&sl->master->mutex); 162 return count; 163 } 164 165 static struct bin_attribute w1_default_attr = { 166 .attr = { 167 .name = "rw", 168 .mode = S_IRUGO | S_IWUSR, 169 .owner = THIS_MODULE, 170 }, 171 .size = PAGE_SIZE, 172 .read = w1_default_read, 173 .write = w1_default_write, 174 }; 175 176 static int w1_default_add_slave(struct w1_slave *sl) 177 { 178 return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr); 179 } 180 181 static void w1_default_remove_slave(struct w1_slave *sl) 182 { 183 sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr); 184 } 185 186 static struct w1_family_ops w1_default_fops = { 187 .add_slave = w1_default_add_slave, 188 .remove_slave = w1_default_remove_slave, 189 }; 190 191 static struct w1_family w1_default_family = { 192 .fops = &w1_default_fops, 193 }; 194 195 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size); 196 197 static struct bus_type w1_bus_type = { 198 .name = "w1", 199 .match = w1_master_match, 200 .uevent = w1_uevent, 201 }; 202 203 struct device_driver w1_master_driver = { 204 .name = "w1_master_driver", 205 .bus = &w1_bus_type, 206 .probe = w1_master_probe, 207 }; 208 209 struct device w1_master_device = { 210 .parent = NULL, 211 .bus = &w1_bus_type, 212 .bus_id = "w1 bus master", 213 .driver = &w1_master_driver, 214 .release = &w1_master_release 215 }; 216 217 static struct device_driver w1_slave_driver = { 218 .name = "w1_slave_driver", 219 .bus = &w1_bus_type, 220 }; 221 222 #if 0 223 struct device w1_slave_device = { 224 .parent = NULL, 225 .bus = &w1_bus_type, 226 .bus_id = "w1 bus slave", 227 .driver = &w1_slave_driver, 228 .release = &w1_slave_release 229 }; 230 #endif /* 0 */ 231 232 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) 233 { 234 struct w1_master *md = dev_to_w1_master(dev); 235 ssize_t count; 236 237 mutex_lock(&md->mutex); 238 count = sprintf(buf, "%s\n", md->name); 239 mutex_unlock(&md->mutex); 240 241 return count; 242 } 243 244 static ssize_t w1_master_attribute_store_search(struct device * dev, 245 struct device_attribute *attr, 246 const char * buf, size_t count) 247 { 248 struct w1_master *md = dev_to_w1_master(dev); 249 250 mutex_lock(&md->mutex); 251 md->search_count = simple_strtol(buf, NULL, 0); 252 mutex_unlock(&md->mutex); 253 254 return count; 255 } 256 257 static ssize_t w1_master_attribute_show_search(struct device *dev, 258 struct device_attribute *attr, 259 char *buf) 260 { 261 struct w1_master *md = dev_to_w1_master(dev); 262 ssize_t count; 263 264 mutex_lock(&md->mutex); 265 count = sprintf(buf, "%d\n", md->search_count); 266 mutex_unlock(&md->mutex); 267 268 return count; 269 } 270 271 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) 272 { 273 struct w1_master *md = dev_to_w1_master(dev); 274 ssize_t count; 275 276 mutex_lock(&md->mutex); 277 count = sprintf(buf, "0x%p\n", md->bus_master); 278 mutex_unlock(&md->mutex); 279 return count; 280 } 281 282 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) 283 { 284 ssize_t count; 285 count = sprintf(buf, "%d\n", w1_timeout); 286 return count; 287 } 288 289 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 290 { 291 struct w1_master *md = dev_to_w1_master(dev); 292 ssize_t count; 293 294 mutex_lock(&md->mutex); 295 count = sprintf(buf, "%d\n", md->max_slave_count); 296 mutex_unlock(&md->mutex); 297 return count; 298 } 299 300 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) 301 { 302 struct w1_master *md = dev_to_w1_master(dev); 303 ssize_t count; 304 305 mutex_lock(&md->mutex); 306 count = sprintf(buf, "%lu\n", md->attempts); 307 mutex_unlock(&md->mutex); 308 return count; 309 } 310 311 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 312 { 313 struct w1_master *md = dev_to_w1_master(dev); 314 ssize_t count; 315 316 mutex_lock(&md->mutex); 317 count = sprintf(buf, "%d\n", md->slave_count); 318 mutex_unlock(&md->mutex); 319 return count; 320 } 321 322 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf) 323 { 324 struct w1_master *md = dev_to_w1_master(dev); 325 int c = PAGE_SIZE; 326 327 mutex_lock(&md->mutex); 328 329 if (md->slave_count == 0) 330 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); 331 else { 332 struct list_head *ent, *n; 333 struct w1_slave *sl; 334 335 list_for_each_safe(ent, n, &md->slist) { 336 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 337 338 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); 339 } 340 } 341 342 mutex_unlock(&md->mutex); 343 344 return PAGE_SIZE - c; 345 } 346 347 #define W1_MASTER_ATTR_RO(_name, _mode) \ 348 struct device_attribute w1_master_attribute_##_name = \ 349 __ATTR(w1_master_##_name, _mode, \ 350 w1_master_attribute_show_##_name, NULL) 351 352 #define W1_MASTER_ATTR_RW(_name, _mode) \ 353 struct device_attribute w1_master_attribute_##_name = \ 354 __ATTR(w1_master_##_name, _mode, \ 355 w1_master_attribute_show_##_name, \ 356 w1_master_attribute_store_##_name) 357 358 static W1_MASTER_ATTR_RO(name, S_IRUGO); 359 static W1_MASTER_ATTR_RO(slaves, S_IRUGO); 360 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); 361 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO); 362 static W1_MASTER_ATTR_RO(attempts, S_IRUGO); 363 static W1_MASTER_ATTR_RO(timeout, S_IRUGO); 364 static W1_MASTER_ATTR_RO(pointer, S_IRUGO); 365 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO); 366 367 static struct attribute *w1_master_default_attrs[] = { 368 &w1_master_attribute_name.attr, 369 &w1_master_attribute_slaves.attr, 370 &w1_master_attribute_slave_count.attr, 371 &w1_master_attribute_max_slave_count.attr, 372 &w1_master_attribute_attempts.attr, 373 &w1_master_attribute_timeout.attr, 374 &w1_master_attribute_pointer.attr, 375 &w1_master_attribute_search.attr, 376 NULL 377 }; 378 379 static struct attribute_group w1_master_defattr_group = { 380 .attrs = w1_master_default_attrs, 381 }; 382 383 int w1_create_master_attributes(struct w1_master *master) 384 { 385 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); 386 } 387 388 static void w1_destroy_master_attributes(struct w1_master *master) 389 { 390 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); 391 } 392 393 #ifdef CONFIG_HOTPLUG 394 static int w1_uevent(struct device *dev, char **envp, int num_envp, 395 char *buffer, int buffer_size) 396 { 397 struct w1_master *md = NULL; 398 struct w1_slave *sl = NULL; 399 char *event_owner, *name; 400 int err, cur_index=0, cur_len=0; 401 402 if (dev->driver == &w1_master_driver) { 403 md = container_of(dev, struct w1_master, dev); 404 event_owner = "master"; 405 name = md->name; 406 } else if (dev->driver == &w1_slave_driver) { 407 sl = container_of(dev, struct w1_slave, dev); 408 event_owner = "slave"; 409 name = sl->name; 410 } else { 411 dev_dbg(dev, "Unknown event.\n"); 412 return -EINVAL; 413 } 414 415 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", 416 event_owner, name, dev->bus_id); 417 418 if (dev->driver != &w1_slave_driver || !sl) 419 return 0; 420 421 err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, 422 &cur_len, "W1_FID=%02X", sl->reg_num.family); 423 if (err) 424 return err; 425 426 err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, 427 &cur_len, "W1_SLAVE_ID=%024LX", 428 (unsigned long long)sl->reg_num.id); 429 if (err) 430 return err; 431 432 return 0; 433 }; 434 #else 435 static int w1_uevent(struct device *dev, char **envp, int num_envp, 436 char *buffer, int buffer_size) 437 { 438 return 0; 439 } 440 #endif 441 442 static int __w1_attach_slave_device(struct w1_slave *sl) 443 { 444 int err; 445 446 sl->dev.parent = &sl->master->dev; 447 sl->dev.driver = &w1_slave_driver; 448 sl->dev.bus = &w1_bus_type; 449 sl->dev.release = &w1_slave_release; 450 451 snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id), 452 "%02x-%012llx", 453 (unsigned int) sl->reg_num.family, 454 (unsigned long long) sl->reg_num.id); 455 snprintf(&sl->name[0], sizeof(sl->name), 456 "%02x-%012llx", 457 (unsigned int) sl->reg_num.family, 458 (unsigned long long) sl->reg_num.id); 459 460 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, 461 &sl->dev.bus_id[0]); 462 463 err = device_register(&sl->dev); 464 if (err < 0) { 465 dev_err(&sl->dev, 466 "Device registration [%s] failed. err=%d\n", 467 sl->dev.bus_id, err); 468 return err; 469 } 470 471 /* Create "name" entry */ 472 err = device_create_file(&sl->dev, &w1_slave_attr_name); 473 if (err < 0) { 474 dev_err(&sl->dev, 475 "sysfs file creation for [%s] failed. err=%d\n", 476 sl->dev.bus_id, err); 477 goto out_unreg; 478 } 479 480 /* Create "id" entry */ 481 err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 482 if (err < 0) { 483 dev_err(&sl->dev, 484 "sysfs file creation for [%s] failed. err=%d\n", 485 sl->dev.bus_id, err); 486 goto out_rem1; 487 } 488 489 /* if the family driver needs to initialize something... */ 490 if (sl->family->fops && sl->family->fops->add_slave && 491 ((err = sl->family->fops->add_slave(sl)) < 0)) { 492 dev_err(&sl->dev, 493 "sysfs file creation for [%s] failed. err=%d\n", 494 sl->dev.bus_id, err); 495 goto out_rem2; 496 } 497 498 list_add_tail(&sl->w1_slave_entry, &sl->master->slist); 499 500 return 0; 501 502 out_rem2: 503 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 504 out_rem1: 505 device_remove_file(&sl->dev, &w1_slave_attr_name); 506 out_unreg: 507 device_unregister(&sl->dev); 508 return err; 509 } 510 511 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 512 { 513 struct w1_slave *sl; 514 struct w1_family *f; 515 int err; 516 struct w1_netlink_msg msg; 517 518 sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL); 519 if (!sl) { 520 dev_err(&dev->dev, 521 "%s: failed to allocate new slave device.\n", 522 __func__); 523 return -ENOMEM; 524 } 525 526 memset(sl, 0, sizeof(*sl)); 527 528 sl->owner = THIS_MODULE; 529 sl->master = dev; 530 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 531 532 memset(&msg, 0, sizeof(msg)); 533 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); 534 atomic_set(&sl->refcnt, 0); 535 init_completion(&sl->released); 536 537 spin_lock(&w1_flock); 538 f = w1_family_registered(rn->family); 539 if (!f) { 540 f= &w1_default_family; 541 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", 542 rn->family, rn->family, 543 (unsigned long long)rn->id, rn->crc); 544 } 545 __w1_family_get(f); 546 spin_unlock(&w1_flock); 547 548 sl->family = f; 549 550 551 err = __w1_attach_slave_device(sl); 552 if (err < 0) { 553 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, 554 sl->name); 555 w1_family_put(sl->family); 556 kfree(sl); 557 return err; 558 } 559 560 sl->ttl = dev->slave_ttl; 561 dev->slave_count++; 562 563 memcpy(msg.id.id, rn, sizeof(msg.id)); 564 msg.type = W1_SLAVE_ADD; 565 w1_netlink_send(dev, &msg); 566 567 return 0; 568 } 569 570 static void w1_slave_detach(struct w1_slave *sl) 571 { 572 struct w1_netlink_msg msg; 573 574 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl); 575 576 list_del(&sl->w1_slave_entry); 577 578 if (sl->family->fops && sl->family->fops->remove_slave) 579 sl->family->fops->remove_slave(sl); 580 581 memset(&msg, 0, sizeof(msg)); 582 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); 583 msg.type = W1_SLAVE_REMOVE; 584 w1_netlink_send(sl->master, &msg); 585 586 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 587 device_remove_file(&sl->dev, &w1_slave_attr_name); 588 device_unregister(&sl->dev); 589 590 wait_for_completion(&sl->released); 591 kfree(sl); 592 } 593 594 static struct w1_master *w1_search_master(void *data) 595 { 596 struct w1_master *dev; 597 int found = 0; 598 599 mutex_lock(&w1_mlock); 600 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 601 if (dev->bus_master->data == data) { 602 found = 1; 603 atomic_inc(&dev->refcnt); 604 break; 605 } 606 } 607 mutex_unlock(&w1_mlock); 608 609 return (found)?dev:NULL; 610 } 611 612 struct w1_master *w1_search_master_id(u32 id) 613 { 614 struct w1_master *dev; 615 int found = 0; 616 617 mutex_lock(&w1_mlock); 618 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 619 if (dev->id == id) { 620 found = 1; 621 atomic_inc(&dev->refcnt); 622 break; 623 } 624 } 625 mutex_unlock(&w1_mlock); 626 627 return (found)?dev:NULL; 628 } 629 630 struct w1_slave *w1_search_slave(struct w1_reg_num *id) 631 { 632 struct w1_master *dev; 633 struct w1_slave *sl = NULL; 634 int found = 0; 635 636 mutex_lock(&w1_mlock); 637 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 638 mutex_lock(&dev->mutex); 639 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 640 if (sl->reg_num.family == id->family && 641 sl->reg_num.id == id->id && 642 sl->reg_num.crc == id->crc) { 643 found = 1; 644 atomic_inc(&dev->refcnt); 645 atomic_inc(&sl->refcnt); 646 break; 647 } 648 } 649 mutex_unlock(&dev->mutex); 650 651 if (found) 652 break; 653 } 654 mutex_unlock(&w1_mlock); 655 656 return (found)?sl:NULL; 657 } 658 659 void w1_reconnect_slaves(struct w1_family *f) 660 { 661 struct w1_master *dev; 662 663 mutex_lock(&w1_mlock); 664 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 665 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n", 666 dev->name, f->fid); 667 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); 668 } 669 mutex_unlock(&w1_mlock); 670 } 671 672 static void w1_slave_found(void *data, u64 rn) 673 { 674 int slave_count; 675 struct w1_slave *sl; 676 struct list_head *ent; 677 struct w1_reg_num *tmp; 678 int family_found = 0; 679 struct w1_master *dev; 680 u64 rn_le = cpu_to_le64(rn); 681 682 dev = w1_search_master(data); 683 if (!dev) { 684 printk(KERN_ERR "Failed to find w1 master device for data %p, " 685 "it is impossible.\n", data); 686 return; 687 } 688 689 tmp = (struct w1_reg_num *) &rn; 690 691 slave_count = 0; 692 list_for_each(ent, &dev->slist) { 693 694 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 695 696 if (sl->reg_num.family == tmp->family && 697 sl->reg_num.id == tmp->id && 698 sl->reg_num.crc == tmp->crc) { 699 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 700 break; 701 } else if (sl->reg_num.family == tmp->family) { 702 family_found = 1; 703 break; 704 } 705 706 slave_count++; 707 } 708 709 if (slave_count == dev->slave_count && 710 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) { 711 w1_attach_slave_device(dev, tmp); 712 } 713 714 atomic_dec(&dev->refcnt); 715 } 716 717 /** 718 * Performs a ROM Search & registers any devices found. 719 * The 1-wire search is a simple binary tree search. 720 * For each bit of the address, we read two bits and write one bit. 721 * The bit written will put to sleep all devies that don't match that bit. 722 * When the two reads differ, the direction choice is obvious. 723 * When both bits are 0, we must choose a path to take. 724 * When we can scan all 64 bits without having to choose a path, we are done. 725 * 726 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com 727 * 728 * @dev The master device to search 729 * @cb Function to call when a device is found 730 */ 731 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) 732 { 733 u64 last_rn, rn, tmp64; 734 int i, slave_count = 0; 735 int last_zero, last_device; 736 int search_bit, desc_bit; 737 u8 triplet_ret = 0; 738 739 search_bit = 0; 740 rn = last_rn = 0; 741 last_device = 0; 742 last_zero = -1; 743 744 desc_bit = 64; 745 746 while ( !last_device && (slave_count++ < dev->max_slave_count) ) { 747 last_rn = rn; 748 rn = 0; 749 750 /* 751 * Reset bus and all 1-wire device state machines 752 * so they can respond to our requests. 753 * 754 * Return 0 - device(s) present, 1 - no devices present. 755 */ 756 if (w1_reset_bus(dev)) { 757 dev_dbg(&dev->dev, "No devices present on the wire.\n"); 758 break; 759 } 760 761 /* Start the search */ 762 w1_write_8(dev, search_type); 763 for (i = 0; i < 64; ++i) { 764 /* Determine the direction/search bit */ 765 if (i == desc_bit) 766 search_bit = 1; /* took the 0 path last time, so take the 1 path */ 767 else if (i > desc_bit) 768 search_bit = 0; /* take the 0 path on the next branch */ 769 else 770 search_bit = ((last_rn >> i) & 0x1); 771 772 /** Read two bits and write one bit */ 773 triplet_ret = w1_triplet(dev, search_bit); 774 775 /* quit if no device responded */ 776 if ( (triplet_ret & 0x03) == 0x03 ) 777 break; 778 779 /* If both directions were valid, and we took the 0 path... */ 780 if (triplet_ret == 0) 781 last_zero = i; 782 783 /* extract the direction taken & update the device number */ 784 tmp64 = (triplet_ret >> 2); 785 rn |= (tmp64 << i); 786 } 787 788 if ( (triplet_ret & 0x03) != 0x03 ) { 789 if ( (desc_bit == last_zero) || (last_zero < 0)) 790 last_device = 1; 791 desc_bit = last_zero; 792 cb(dev->bus_master->data, rn); 793 } 794 } 795 } 796 797 static int w1_control(void *data) 798 { 799 struct w1_slave *sl, *sln; 800 struct w1_master *dev, *n; 801 int have_to_wait = 0; 802 803 while (!kthread_should_stop() || have_to_wait) { 804 have_to_wait = 0; 805 806 try_to_freeze(); 807 msleep_interruptible(w1_control_timeout * 1000); 808 809 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) { 810 if (!kthread_should_stop() && !dev->flags) 811 continue; 812 /* 813 * Little race: we can create thread but not set the flag. 814 * Get a chance for external process to set flag up. 815 */ 816 if (!dev->initialized) { 817 have_to_wait = 1; 818 continue; 819 } 820 821 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 822 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 823 824 mutex_lock(&w1_mlock); 825 list_del(&dev->w1_master_entry); 826 mutex_unlock(&w1_mlock); 827 828 mutex_lock(&dev->mutex); 829 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 830 w1_slave_detach(sl); 831 } 832 w1_destroy_master_attributes(dev); 833 mutex_unlock(&dev->mutex); 834 atomic_dec(&dev->refcnt); 835 continue; 836 } 837 838 if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) { 839 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name); 840 mutex_lock(&dev->mutex); 841 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 842 if (sl->family->fid == W1_FAMILY_DEFAULT) { 843 struct w1_reg_num rn; 844 845 memcpy(&rn, &sl->reg_num, sizeof(rn)); 846 w1_slave_detach(sl); 847 848 w1_attach_slave_device(dev, &rn); 849 } 850 } 851 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name); 852 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); 853 mutex_unlock(&dev->mutex); 854 } 855 } 856 } 857 858 return 0; 859 } 860 861 void w1_search_process(struct w1_master *dev, u8 search_type) 862 { 863 struct w1_slave *sl, *sln; 864 865 list_for_each_entry(sl, &dev->slist, w1_slave_entry) 866 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 867 868 w1_search_devices(dev, search_type, w1_slave_found); 869 870 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 871 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) { 872 w1_slave_detach(sl); 873 874 dev->slave_count--; 875 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags)) 876 sl->ttl = dev->slave_ttl; 877 } 878 879 if (dev->search_count > 0) 880 dev->search_count--; 881 } 882 883 int w1_process(void *data) 884 { 885 struct w1_master *dev = (struct w1_master *) data; 886 887 while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 888 try_to_freeze(); 889 msleep_interruptible(w1_timeout * 1000); 890 891 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) 892 break; 893 894 if (!dev->initialized) 895 continue; 896 897 if (dev->search_count == 0) 898 continue; 899 900 mutex_lock(&dev->mutex); 901 w1_search_process(dev, W1_SEARCH); 902 mutex_unlock(&dev->mutex); 903 } 904 905 atomic_dec(&dev->refcnt); 906 907 return 0; 908 } 909 910 static int w1_init(void) 911 { 912 int retval; 913 914 printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n"); 915 916 w1_init_netlink(); 917 918 retval = bus_register(&w1_bus_type); 919 if (retval) { 920 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval); 921 goto err_out_exit_init; 922 } 923 924 retval = driver_register(&w1_master_driver); 925 if (retval) { 926 printk(KERN_ERR 927 "Failed to register master driver. err=%d.\n", 928 retval); 929 goto err_out_bus_unregister; 930 } 931 932 retval = driver_register(&w1_slave_driver); 933 if (retval) { 934 printk(KERN_ERR 935 "Failed to register master driver. err=%d.\n", 936 retval); 937 goto err_out_master_unregister; 938 } 939 940 w1_control_thread = kthread_run(w1_control, NULL, "w1_control"); 941 if (IS_ERR(w1_control_thread)) { 942 retval = PTR_ERR(w1_control_thread); 943 printk(KERN_ERR "Failed to create control thread. err=%d\n", 944 retval); 945 goto err_out_slave_unregister; 946 } 947 948 return 0; 949 950 err_out_slave_unregister: 951 driver_unregister(&w1_slave_driver); 952 953 err_out_master_unregister: 954 driver_unregister(&w1_master_driver); 955 956 err_out_bus_unregister: 957 bus_unregister(&w1_bus_type); 958 959 err_out_exit_init: 960 return retval; 961 } 962 963 static void w1_fini(void) 964 { 965 struct w1_master *dev; 966 967 list_for_each_entry(dev, &w1_masters, w1_master_entry) 968 __w1_remove_master_device(dev); 969 970 w1_fini_netlink(); 971 972 kthread_stop(w1_control_thread); 973 974 driver_unregister(&w1_slave_driver); 975 driver_unregister(&w1_master_driver); 976 bus_unregister(&w1_bus_type); 977 } 978 979 module_init(w1_init); 980 module_exit(w1_fini); 981