w1.c revision 0d671b272af9eb06260ab3fd210d454e98dd4216
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#include <linux/freezer.h> 35 36#include <asm/atomic.h> 37 38#include "w1.h" 39#include "w1_log.h" 40#include "w1_int.h" 41#include "w1_family.h" 42#include "w1_netlink.h" 43 44MODULE_LICENSE("GPL"); 45MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); 46MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); 47 48static int w1_timeout = 10; 49int w1_max_slave_count = 10; 50int w1_max_slave_ttl = 10; 51 52module_param_named(timeout, w1_timeout, int, 0); 53module_param_named(max_slave_count, w1_max_slave_count, int, 0); 54module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); 55 56DEFINE_MUTEX(w1_mlock); 57LIST_HEAD(w1_masters); 58 59static int w1_master_match(struct device *dev, struct device_driver *drv) 60{ 61 return 1; 62} 63 64static int w1_master_probe(struct device *dev) 65{ 66 return -ENODEV; 67} 68 69static void w1_master_release(struct device *dev) 70{ 71 struct w1_master *md = dev_to_w1_master(dev); 72 73 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); 74 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 75 kfree(md); 76} 77 78static void w1_slave_release(struct device *dev) 79{ 80 struct w1_slave *sl = dev_to_w1_slave(dev); 81 82 printk("%s: Releasing %s.\n", __func__, sl->name); 83 84 while (atomic_read(&sl->refcnt)) { 85 printk("Waiting for %s to become free: refcnt=%d.\n", 86 sl->name, atomic_read(&sl->refcnt)); 87 if (msleep_interruptible(1000)) 88 flush_signals(current); 89 } 90 91 w1_family_put(sl->family); 92 sl->master->slave_count--; 93 94 complete(&sl->released); 95} 96 97static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf) 98{ 99 struct w1_slave *sl = dev_to_w1_slave(dev); 100 101 return sprintf(buf, "%s\n", sl->name); 102} 103 104static ssize_t w1_slave_read_id(struct kobject *kobj, 105 struct bin_attribute *bin_attr, 106 char *buf, loff_t off, size_t count) 107{ 108 struct w1_slave *sl = kobj_to_w1_slave(kobj); 109 110 if (off > 8) { 111 count = 0; 112 } else { 113 if (off + count > 8) 114 count = 8 - off; 115 116 memcpy(buf, (u8 *)&sl->reg_num, count); 117 } 118 119 return count; 120} 121 122static struct device_attribute w1_slave_attr_name = 123 __ATTR(name, S_IRUGO, w1_slave_read_name, NULL); 124 125static struct bin_attribute w1_slave_attr_bin_id = { 126 .attr = { 127 .name = "id", 128 .mode = S_IRUGO, 129 }, 130 .size = 8, 131 .read = w1_slave_read_id, 132}; 133 134/* Default family */ 135 136static ssize_t w1_default_write(struct kobject *kobj, 137 struct bin_attribute *bin_attr, 138 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 150out_up: 151 mutex_unlock(&sl->master->mutex); 152 return count; 153} 154 155static ssize_t w1_default_read(struct kobject *kobj, 156 struct bin_attribute *bin_attr, 157 char *buf, loff_t off, size_t count) 158{ 159 struct w1_slave *sl = kobj_to_w1_slave(kobj); 160 161 mutex_lock(&sl->master->mutex); 162 w1_read_block(sl->master, buf, count); 163 mutex_unlock(&sl->master->mutex); 164 return count; 165} 166 167static struct bin_attribute w1_default_attr = { 168 .attr = { 169 .name = "rw", 170 .mode = S_IRUGO | S_IWUSR, 171 }, 172 .size = PAGE_SIZE, 173 .read = w1_default_read, 174 .write = w1_default_write, 175}; 176 177static int w1_default_add_slave(struct w1_slave *sl) 178{ 179 return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr); 180} 181 182static void w1_default_remove_slave(struct w1_slave *sl) 183{ 184 sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr); 185} 186 187static struct w1_family_ops w1_default_fops = { 188 .add_slave = w1_default_add_slave, 189 .remove_slave = w1_default_remove_slave, 190}; 191 192static struct w1_family w1_default_family = { 193 .fops = &w1_default_fops, 194}; 195 196static int w1_uevent(struct device *dev, struct kobj_uevent_env *env); 197 198static struct bus_type w1_bus_type = { 199 .name = "w1", 200 .match = w1_master_match, 201 .uevent = w1_uevent, 202}; 203 204struct device_driver w1_master_driver = { 205 .name = "w1_master_driver", 206 .bus = &w1_bus_type, 207 .probe = w1_master_probe, 208}; 209 210struct device w1_master_device = { 211 .parent = NULL, 212 .bus = &w1_bus_type, 213 .bus_id = "w1 bus master", 214 .driver = &w1_master_driver, 215 .release = &w1_master_release 216}; 217 218static struct device_driver w1_slave_driver = { 219 .name = "w1_slave_driver", 220 .bus = &w1_bus_type, 221}; 222 223#if 0 224struct device w1_slave_device = { 225 .parent = NULL, 226 .bus = &w1_bus_type, 227 .bus_id = "w1 bus slave", 228 .driver = &w1_slave_driver, 229 .release = &w1_slave_release 230}; 231#endif /* 0 */ 232 233static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) 234{ 235 struct w1_master *md = dev_to_w1_master(dev); 236 ssize_t count; 237 238 mutex_lock(&md->mutex); 239 count = sprintf(buf, "%s\n", md->name); 240 mutex_unlock(&md->mutex); 241 242 return count; 243} 244 245static ssize_t w1_master_attribute_store_search(struct device * dev, 246 struct device_attribute *attr, 247 const char * buf, size_t count) 248{ 249 struct w1_master *md = dev_to_w1_master(dev); 250 251 mutex_lock(&md->mutex); 252 md->search_count = simple_strtol(buf, NULL, 0); 253 mutex_unlock(&md->mutex); 254 255 return count; 256} 257 258static ssize_t w1_master_attribute_show_search(struct device *dev, 259 struct device_attribute *attr, 260 char *buf) 261{ 262 struct w1_master *md = dev_to_w1_master(dev); 263 ssize_t count; 264 265 mutex_lock(&md->mutex); 266 count = sprintf(buf, "%d\n", md->search_count); 267 mutex_unlock(&md->mutex); 268 269 return count; 270} 271 272static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) 273{ 274 struct w1_master *md = dev_to_w1_master(dev); 275 ssize_t count; 276 277 mutex_lock(&md->mutex); 278 count = sprintf(buf, "0x%p\n", md->bus_master); 279 mutex_unlock(&md->mutex); 280 return count; 281} 282 283static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) 284{ 285 ssize_t count; 286 count = sprintf(buf, "%d\n", w1_timeout); 287 return count; 288} 289 290static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 291{ 292 struct w1_master *md = dev_to_w1_master(dev); 293 ssize_t count; 294 295 mutex_lock(&md->mutex); 296 count = sprintf(buf, "%d\n", md->max_slave_count); 297 mutex_unlock(&md->mutex); 298 return count; 299} 300 301static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) 302{ 303 struct w1_master *md = dev_to_w1_master(dev); 304 ssize_t count; 305 306 mutex_lock(&md->mutex); 307 count = sprintf(buf, "%lu\n", md->attempts); 308 mutex_unlock(&md->mutex); 309 return count; 310} 311 312static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 313{ 314 struct w1_master *md = dev_to_w1_master(dev); 315 ssize_t count; 316 317 mutex_lock(&md->mutex); 318 count = sprintf(buf, "%d\n", md->slave_count); 319 mutex_unlock(&md->mutex); 320 return count; 321} 322 323static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf) 324{ 325 struct w1_master *md = dev_to_w1_master(dev); 326 int c = PAGE_SIZE; 327 328 mutex_lock(&md->mutex); 329 330 if (md->slave_count == 0) 331 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); 332 else { 333 struct list_head *ent, *n; 334 struct w1_slave *sl; 335 336 list_for_each_safe(ent, n, &md->slist) { 337 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 338 339 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); 340 } 341 } 342 343 mutex_unlock(&md->mutex); 344 345 return PAGE_SIZE - c; 346} 347 348#define W1_MASTER_ATTR_RO(_name, _mode) \ 349 struct device_attribute w1_master_attribute_##_name = \ 350 __ATTR(w1_master_##_name, _mode, \ 351 w1_master_attribute_show_##_name, NULL) 352 353#define W1_MASTER_ATTR_RW(_name, _mode) \ 354 struct device_attribute w1_master_attribute_##_name = \ 355 __ATTR(w1_master_##_name, _mode, \ 356 w1_master_attribute_show_##_name, \ 357 w1_master_attribute_store_##_name) 358 359static W1_MASTER_ATTR_RO(name, S_IRUGO); 360static W1_MASTER_ATTR_RO(slaves, S_IRUGO); 361static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); 362static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO); 363static W1_MASTER_ATTR_RO(attempts, S_IRUGO); 364static W1_MASTER_ATTR_RO(timeout, S_IRUGO); 365static W1_MASTER_ATTR_RO(pointer, S_IRUGO); 366static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO); 367 368static struct attribute *w1_master_default_attrs[] = { 369 &w1_master_attribute_name.attr, 370 &w1_master_attribute_slaves.attr, 371 &w1_master_attribute_slave_count.attr, 372 &w1_master_attribute_max_slave_count.attr, 373 &w1_master_attribute_attempts.attr, 374 &w1_master_attribute_timeout.attr, 375 &w1_master_attribute_pointer.attr, 376 &w1_master_attribute_search.attr, 377 NULL 378}; 379 380static struct attribute_group w1_master_defattr_group = { 381 .attrs = w1_master_default_attrs, 382}; 383 384int w1_create_master_attributes(struct w1_master *master) 385{ 386 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); 387} 388 389void w1_destroy_master_attributes(struct w1_master *master) 390{ 391 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); 392} 393 394#ifdef CONFIG_HOTPLUG 395static int w1_uevent(struct device *dev, struct kobj_uevent_env *env) 396{ 397 struct w1_master *md = NULL; 398 struct w1_slave *sl = NULL; 399 char *event_owner, *name; 400 int err; 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(env, "W1_FID=%02X", sl->reg_num.family); 422 if (err) 423 return err; 424 425 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX", 426 (unsigned long long)sl->reg_num.id); 427 if (err) 428 return err; 429 430 return 0; 431}; 432#else 433static int w1_uevent(struct device *dev, struct kobj_uevent_env *env) 434{ 435 return 0; 436} 437#endif 438 439static int __w1_attach_slave_device(struct w1_slave *sl) 440{ 441 int err; 442 443 sl->dev.parent = &sl->master->dev; 444 sl->dev.driver = &w1_slave_driver; 445 sl->dev.bus = &w1_bus_type; 446 sl->dev.release = &w1_slave_release; 447 448 snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id), 449 "%02x-%012llx", 450 (unsigned int) sl->reg_num.family, 451 (unsigned long long) sl->reg_num.id); 452 snprintf(&sl->name[0], sizeof(sl->name), 453 "%02x-%012llx", 454 (unsigned int) sl->reg_num.family, 455 (unsigned long long) sl->reg_num.id); 456 457 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, 458 &sl->dev.bus_id[0], sl); 459 460 err = device_register(&sl->dev); 461 if (err < 0) { 462 dev_err(&sl->dev, 463 "Device registration [%s] failed. err=%d\n", 464 sl->dev.bus_id, err); 465 return err; 466 } 467 468 /* Create "name" entry */ 469 err = device_create_file(&sl->dev, &w1_slave_attr_name); 470 if (err < 0) { 471 dev_err(&sl->dev, 472 "sysfs file creation for [%s] failed. err=%d\n", 473 sl->dev.bus_id, err); 474 goto out_unreg; 475 } 476 477 /* Create "id" entry */ 478 err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 479 if (err < 0) { 480 dev_err(&sl->dev, 481 "sysfs file creation for [%s] failed. err=%d\n", 482 sl->dev.bus_id, err); 483 goto out_rem1; 484 } 485 486 /* if the family driver needs to initialize something... */ 487 if (sl->family->fops && sl->family->fops->add_slave && 488 ((err = sl->family->fops->add_slave(sl)) < 0)) { 489 dev_err(&sl->dev, 490 "sysfs file creation for [%s] failed. err=%d\n", 491 sl->dev.bus_id, err); 492 goto out_rem2; 493 } 494 495 list_add_tail(&sl->w1_slave_entry, &sl->master->slist); 496 497 return 0; 498 499out_rem2: 500 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 501out_rem1: 502 device_remove_file(&sl->dev, &w1_slave_attr_name); 503out_unreg: 504 device_unregister(&sl->dev); 505 return err; 506} 507 508static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 509{ 510 struct w1_slave *sl; 511 struct w1_family *f; 512 int err; 513 struct w1_netlink_msg msg; 514 515 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL); 516 if (!sl) { 517 dev_err(&dev->dev, 518 "%s: failed to allocate new slave device.\n", 519 __func__); 520 return -ENOMEM; 521 } 522 523 524 sl->owner = THIS_MODULE; 525 sl->master = dev; 526 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 527 528 memset(&msg, 0, sizeof(msg)); 529 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); 530 atomic_set(&sl->refcnt, 0); 531 init_completion(&sl->released); 532 533 spin_lock(&w1_flock); 534 f = w1_family_registered(rn->family); 535 if (!f) { 536 f= &w1_default_family; 537 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", 538 rn->family, rn->family, 539 (unsigned long long)rn->id, rn->crc); 540 } 541 __w1_family_get(f); 542 spin_unlock(&w1_flock); 543 544 sl->family = f; 545 546 547 err = __w1_attach_slave_device(sl); 548 if (err < 0) { 549 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, 550 sl->name); 551 w1_family_put(sl->family); 552 kfree(sl); 553 return err; 554 } 555 556 sl->ttl = dev->slave_ttl; 557 dev->slave_count++; 558 559 memcpy(msg.id.id, rn, sizeof(msg.id)); 560 msg.type = W1_SLAVE_ADD; 561 w1_netlink_send(dev, &msg); 562 563 return 0; 564} 565 566void w1_slave_detach(struct w1_slave *sl) 567{ 568 struct w1_netlink_msg msg; 569 570 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl); 571 572 list_del(&sl->w1_slave_entry); 573 574 if (sl->family->fops && sl->family->fops->remove_slave) 575 sl->family->fops->remove_slave(sl); 576 577 memset(&msg, 0, sizeof(msg)); 578 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); 579 msg.type = W1_SLAVE_REMOVE; 580 w1_netlink_send(sl->master, &msg); 581 582 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 583 device_remove_file(&sl->dev, &w1_slave_attr_name); 584 device_unregister(&sl->dev); 585 586 wait_for_completion(&sl->released); 587 kfree(sl); 588} 589 590struct w1_master *w1_search_master_id(u32 id) 591{ 592 struct w1_master *dev; 593 int found = 0; 594 595 mutex_lock(&w1_mlock); 596 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 597 if (dev->id == id) { 598 found = 1; 599 atomic_inc(&dev->refcnt); 600 break; 601 } 602 } 603 mutex_unlock(&w1_mlock); 604 605 return (found)?dev:NULL; 606} 607 608struct w1_slave *w1_search_slave(struct w1_reg_num *id) 609{ 610 struct w1_master *dev; 611 struct w1_slave *sl = NULL; 612 int found = 0; 613 614 mutex_lock(&w1_mlock); 615 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 616 mutex_lock(&dev->mutex); 617 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 618 if (sl->reg_num.family == id->family && 619 sl->reg_num.id == id->id && 620 sl->reg_num.crc == id->crc) { 621 found = 1; 622 atomic_inc(&dev->refcnt); 623 atomic_inc(&sl->refcnt); 624 break; 625 } 626 } 627 mutex_unlock(&dev->mutex); 628 629 if (found) 630 break; 631 } 632 mutex_unlock(&w1_mlock); 633 634 return (found)?sl:NULL; 635} 636 637void w1_reconnect_slaves(struct w1_family *f, int attach) 638{ 639 struct w1_slave *sl, *sln; 640 struct w1_master *dev; 641 642 mutex_lock(&w1_mlock); 643 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 644 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 645 "for family %02x.\n", dev->name, f->fid); 646 mutex_lock(&dev->mutex); 647 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 648 /* If it is a new family, slaves with the default 649 * family driver and are that family will be 650 * connected. If the family is going away, devices 651 * matching that family are reconneced. 652 */ 653 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT 654 && sl->reg_num.family == f->fid) || 655 (!attach && sl->family->fid == f->fid)) { 656 struct w1_reg_num rn; 657 658 memcpy(&rn, &sl->reg_num, sizeof(rn)); 659 w1_slave_detach(sl); 660 661 w1_attach_slave_device(dev, &rn); 662 } 663 } 664 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 665 "has been finished.\n", dev->name); 666 mutex_unlock(&dev->mutex); 667 } 668 mutex_unlock(&w1_mlock); 669} 670 671static void w1_slave_found(struct w1_master *dev, u64 rn) 672{ 673 int slave_count; 674 struct w1_slave *sl; 675 struct list_head *ent; 676 struct w1_reg_num *tmp; 677 u64 rn_le = cpu_to_le64(rn); 678 679 atomic_inc(&dev->refcnt); 680 681 tmp = (struct w1_reg_num *) &rn; 682 683 slave_count = 0; 684 list_for_each(ent, &dev->slist) { 685 686 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 687 688 if (sl->reg_num.family == tmp->family && 689 sl->reg_num.id == tmp->id && 690 sl->reg_num.crc == tmp->crc) { 691 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 692 break; 693 } 694 695 slave_count++; 696 } 697 698 if (slave_count == dev->slave_count && 699 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) { 700 w1_attach_slave_device(dev, tmp); 701 } 702 703 atomic_dec(&dev->refcnt); 704} 705 706/** 707 * Performs a ROM Search & registers any devices found. 708 * The 1-wire search is a simple binary tree search. 709 * For each bit of the address, we read two bits and write one bit. 710 * The bit written will put to sleep all devies that don't match that bit. 711 * When the two reads differ, the direction choice is obvious. 712 * When both bits are 0, we must choose a path to take. 713 * When we can scan all 64 bits without having to choose a path, we are done. 714 * 715 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com 716 * 717 * @dev The master device to search 718 * @cb Function to call when a device is found 719 */ 720void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) 721{ 722 u64 last_rn, rn, tmp64; 723 int i, slave_count = 0; 724 int last_zero, last_device; 725 int search_bit, desc_bit; 726 u8 triplet_ret = 0; 727 728 search_bit = 0; 729 rn = last_rn = 0; 730 last_device = 0; 731 last_zero = -1; 732 733 desc_bit = 64; 734 735 while ( !last_device && (slave_count++ < dev->max_slave_count) ) { 736 last_rn = rn; 737 rn = 0; 738 739 /* 740 * Reset bus and all 1-wire device state machines 741 * so they can respond to our requests. 742 * 743 * Return 0 - device(s) present, 1 - no devices present. 744 */ 745 if (w1_reset_bus(dev)) { 746 dev_dbg(&dev->dev, "No devices present on the wire.\n"); 747 break; 748 } 749 750 /* Start the search */ 751 w1_write_8(dev, search_type); 752 for (i = 0; i < 64; ++i) { 753 /* Determine the direction/search bit */ 754 if (i == desc_bit) 755 search_bit = 1; /* took the 0 path last time, so take the 1 path */ 756 else if (i > desc_bit) 757 search_bit = 0; /* take the 0 path on the next branch */ 758 else 759 search_bit = ((last_rn >> i) & 0x1); 760 761 /** Read two bits and write one bit */ 762 triplet_ret = w1_triplet(dev, search_bit); 763 764 /* quit if no device responded */ 765 if ( (triplet_ret & 0x03) == 0x03 ) 766 break; 767 768 /* If both directions were valid, and we took the 0 path... */ 769 if (triplet_ret == 0) 770 last_zero = i; 771 772 /* extract the direction taken & update the device number */ 773 tmp64 = (triplet_ret >> 2); 774 rn |= (tmp64 << i); 775 776 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 777 printk(KERN_INFO "Abort w1_search (exiting)\n"); 778 return; 779 } 780 } 781 782 if ( (triplet_ret & 0x03) != 0x03 ) { 783 if ( (desc_bit == last_zero) || (last_zero < 0)) 784 last_device = 1; 785 desc_bit = last_zero; 786 cb(dev, rn); 787 } 788 } 789} 790 791void w1_search_process(struct w1_master *dev, u8 search_type) 792{ 793 struct w1_slave *sl, *sln; 794 795 list_for_each_entry(sl, &dev->slist, w1_slave_entry) 796 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 797 798 w1_search_devices(dev, search_type, w1_slave_found); 799 800 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 801 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) 802 w1_slave_detach(sl); 803 else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags)) 804 sl->ttl = dev->slave_ttl; 805 } 806 807 if (dev->search_count > 0) 808 dev->search_count--; 809} 810 811int w1_process(void *data) 812{ 813 struct w1_master *dev = (struct w1_master *) data; 814 815 while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 816 try_to_freeze(); 817 msleep_interruptible(w1_timeout * 1000); 818 819 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) 820 break; 821 822 if (!dev->initialized) 823 continue; 824 825 if (dev->search_count == 0) 826 continue; 827 828 mutex_lock(&dev->mutex); 829 w1_search_process(dev, W1_SEARCH); 830 mutex_unlock(&dev->mutex); 831 } 832 833 atomic_dec(&dev->refcnt); 834 835 return 0; 836} 837 838static int w1_init(void) 839{ 840 int retval; 841 842 printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n"); 843 844 w1_init_netlink(); 845 846 retval = bus_register(&w1_bus_type); 847 if (retval) { 848 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval); 849 goto err_out_exit_init; 850 } 851 852 retval = driver_register(&w1_master_driver); 853 if (retval) { 854 printk(KERN_ERR 855 "Failed to register master driver. err=%d.\n", 856 retval); 857 goto err_out_bus_unregister; 858 } 859 860 retval = driver_register(&w1_slave_driver); 861 if (retval) { 862 printk(KERN_ERR 863 "Failed to register master driver. err=%d.\n", 864 retval); 865 goto err_out_master_unregister; 866 } 867 868 return 0; 869 870#if 0 871/* For undoing the slave register if there was a step after it. */ 872err_out_slave_unregister: 873 driver_unregister(&w1_slave_driver); 874#endif 875 876err_out_master_unregister: 877 driver_unregister(&w1_master_driver); 878 879err_out_bus_unregister: 880 bus_unregister(&w1_bus_type); 881 882err_out_exit_init: 883 return retval; 884} 885 886static void w1_fini(void) 887{ 888 struct w1_master *dev; 889 890 /* Set netlink removal messages and some cleanup */ 891 list_for_each_entry(dev, &w1_masters, w1_master_entry) 892 __w1_remove_master_device(dev); 893 894 w1_fini_netlink(); 895 896 driver_unregister(&w1_slave_driver); 897 driver_unregister(&w1_master_driver); 898 bus_unregister(&w1_bus_type); 899} 900 901module_init(w1_init); 902module_exit(w1_fini); 903