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 44 MODULE_LICENSE("GPL"); 45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); 46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); 47 48 static int w1_timeout = 10; 49 static int w1_control_timeout = 1; 50 int w1_max_slave_count = 10; 51 int w1_max_slave_ttl = 10; 52 53 module_param_named(timeout, w1_timeout, int, 0); 54 module_param_named(control_timeout, w1_control_timeout, int, 0); 55 module_param_named(max_slave_count, w1_max_slave_count, int, 0); 56 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); 57 58 DEFINE_MUTEX(w1_mlock); 59 LIST_HEAD(w1_masters); 60 61 static struct task_struct *w1_control_thread; 62 63 static int w1_master_match(struct device *dev, struct device_driver *drv) 64 { 65 return 1; 66 } 67 68 static int w1_master_probe(struct device *dev) 69 { 70 return -ENODEV; 71 } 72 73 static void w1_master_release(struct device *dev) 74 { 75 struct w1_master *md = dev_to_w1_master(dev); 76 77 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); 78 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 79 kfree(md); 80 } 81 82 static void w1_slave_release(struct device *dev) 83 { 84 struct w1_slave *sl = dev_to_w1_slave(dev); 85 86 printk("%s: Releasing %s.\n", __func__, sl->name); 87 88 while (atomic_read(&sl->refcnt)) { 89 printk("Waiting for %s to become free: refcnt=%d.\n", 90 sl->name, atomic_read(&sl->refcnt)); 91 if (msleep_interruptible(1000)) 92 flush_signals(current); 93 } 94 95 w1_family_put(sl->family); 96 sl->master->slave_count--; 97 98 complete(&sl->released); 99 } 100 101 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf) 102 { 103 struct w1_slave *sl = dev_to_w1_slave(dev); 104 105 return sprintf(buf, "%s\n", sl->name); 106 } 107 108 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count) 109 { 110 struct w1_slave *sl = kobj_to_w1_slave(kobj); 111 112 if (off > 8) { 113 count = 0; 114 } else { 115 if (off + count > 8) 116 count = 8 - off; 117 118 memcpy(buf, (u8 *)&sl->reg_num, count); 119 } 120 121 return count; 122 } 123 124 static struct device_attribute w1_slave_attr_name = 125 __ATTR(name, S_IRUGO, w1_slave_read_name, NULL); 126 127 static struct bin_attribute w1_slave_attr_bin_id = { 128 .attr = { 129 .name = "id", 130 .mode = S_IRUGO, 131 .owner = THIS_MODULE, 132 }, 133 .size = 8, 134 .read = w1_slave_read_id, 135 }; 136 137 /* Default family */ 138 139 static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count) 140 { 141 struct w1_slave *sl = kobj_to_w1_slave(kobj); 142 143 mutex_lock(&sl->master->mutex); 144 if (w1_reset_select_slave(sl)) { 145 count = 0; 146 goto out_up; 147 } 148 149 w1_write_block(sl->master, buf, count); 150 151 out_up: 152 mutex_unlock(&sl->master->mutex); 153 return count; 154 } 155 156 static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count) 157 { 158 struct w1_slave *sl = kobj_to_w1_slave(kobj); 159 160 mutex_lock(&sl->master->mutex); 161 w1_read_block(sl->master, buf, count); 162 mutex_unlock(&sl->master->mutex); 163 return count; 164 } 165 166 static struct bin_attribute w1_default_attr = { 167 .attr = { 168 .name = "rw", 169 .mode = S_IRUGO | S_IWUSR, 170 .owner = THIS_MODULE, 171 }, 172 .size = PAGE_SIZE, 173 .read = w1_default_read, 174 .write = w1_default_write, 175 }; 176 177 static int w1_default_add_slave(struct w1_slave *sl) 178 { 179 return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr); 180 } 181 182 static void w1_default_remove_slave(struct w1_slave *sl) 183 { 184 sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr); 185 } 186 187 static struct w1_family_ops w1_default_fops = { 188 .add_slave = w1_default_add_slave, 189 .remove_slave = w1_default_remove_slave, 190 }; 191 192 static struct w1_family w1_default_family = { 193 .fops = &w1_default_fops, 194 }; 195 196 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size); 197 198 static struct bus_type w1_bus_type = { 199 .name = "w1", 200 .match = w1_master_match, 201 .uevent = w1_uevent, 202 }; 203 204 struct device_driver w1_master_driver = { 205 .name = "w1_master_driver", 206 .bus = &w1_bus_type, 207 .probe = w1_master_probe, 208 }; 209 210 struct 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 }; 217 218 static struct device_driver w1_slave_driver = { 219 .name = "w1_slave_driver", 220 .bus = &w1_bus_type, 221 }; 222 223 #if 0 224 struct 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 */ 232 233 static 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 } 244 245 static 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 } 257 258 static 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 } 271 272 static 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 } 282 283 static 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 } 289 290 static 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 } 300 301 static 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 } 311 312 static 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 } 322 323 static 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) 358 359 static W1_MASTER_ATTR_RO(name, S_IRUGO); 360 static W1_MASTER_ATTR_RO(slaves, S_IRUGO); 361 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); 362 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO); 363 static W1_MASTER_ATTR_RO(attempts, S_IRUGO); 364 static W1_MASTER_ATTR_RO(timeout, S_IRUGO); 365 static W1_MASTER_ATTR_RO(pointer, S_IRUGO); 366 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO); 367 368 static 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 }; 379 380 static struct attribute_group w1_master_defattr_group = { 381 .attrs = w1_master_default_attrs, 382 }; 383 384 int w1_create_master_attributes(struct w1_master *master) 385 { 386 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); 387 } 388 389 static void 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 395 static int w1_uevent(struct device *dev, char **envp, int num_envp, 396 char *buffer, int buffer_size) 397 { 398 struct w1_master *md = NULL; 399 struct w1_slave *sl = NULL; 400 char *event_owner, *name; 401 int err, cur_index=0, cur_len=0; 402 403 if (dev->driver == &w1_master_driver) { 404 md = container_of(dev, struct w1_master, dev); 405 event_owner = "master"; 406 name = md->name; 407 } else if (dev->driver == &w1_slave_driver) { 408 sl = container_of(dev, struct w1_slave, dev); 409 event_owner = "slave"; 410 name = sl->name; 411 } else { 412 dev_dbg(dev, "Unknown event.\n"); 413 return -EINVAL; 414 } 415 416 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", 417 event_owner, name, dev->bus_id); 418 419 if (dev->driver != &w1_slave_driver || !sl) 420 return 0; 421 422 err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, 423 &cur_len, "W1_FID=%02X", sl->reg_num.family); 424 if (err) 425 return err; 426 427 err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, 428 &cur_len, "W1_SLAVE_ID=%024LX", 429 (unsigned long long)sl->reg_num.id); 430 if (err) 431 return err; 432 433 return 0; 434 }; 435 #else 436 static int w1_uevent(struct device *dev, char **envp, int num_envp, 437 char *buffer, int buffer_size) 438 { 439 return 0; 440 } 441 #endif 442 443 static int __w1_attach_slave_device(struct w1_slave *sl) 444 { 445 int err; 446 447 sl->dev.parent = &sl->master->dev; 448 sl->dev.driver = &w1_slave_driver; 449 sl->dev.bus = &w1_bus_type; 450 sl->dev.release = &w1_slave_release; 451 452 snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id), 453 "%02x-%012llx", 454 (unsigned int) sl->reg_num.family, 455 (unsigned long long) sl->reg_num.id); 456 snprintf(&sl->name[0], sizeof(sl->name), 457 "%02x-%012llx", 458 (unsigned int) sl->reg_num.family, 459 (unsigned long long) sl->reg_num.id); 460 461 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, 462 &sl->dev.bus_id[0], sl); 463 464 err = device_register(&sl->dev); 465 if (err < 0) { 466 dev_err(&sl->dev, 467 "Device registration [%s] failed. err=%d\n", 468 sl->dev.bus_id, err); 469 return err; 470 } 471 472 /* Create "name" entry */ 473 err = device_create_file(&sl->dev, &w1_slave_attr_name); 474 if (err < 0) { 475 dev_err(&sl->dev, 476 "sysfs file creation for [%s] failed. err=%d\n", 477 sl->dev.bus_id, err); 478 goto out_unreg; 479 } 480 481 /* Create "id" entry */ 482 err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 483 if (err < 0) { 484 dev_err(&sl->dev, 485 "sysfs file creation for [%s] failed. err=%d\n", 486 sl->dev.bus_id, err); 487 goto out_rem1; 488 } 489 490 /* if the family driver needs to initialize something... */ 491 if (sl->family->fops && sl->family->fops->add_slave && 492 ((err = sl->family->fops->add_slave(sl)) < 0)) { 493 dev_err(&sl->dev, 494 "sysfs file creation for [%s] failed. err=%d\n", 495 sl->dev.bus_id, err); 496 goto out_rem2; 497 } 498 499 list_add_tail(&sl->w1_slave_entry, &sl->master->slist); 500 501 return 0; 502 503 out_rem2: 504 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 505 out_rem1: 506 device_remove_file(&sl->dev, &w1_slave_attr_name); 507 out_unreg: 508 device_unregister(&sl->dev); 509 return err; 510 } 511 512 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 513 { 514 struct w1_slave *sl; 515 struct w1_family *f; 516 int err; 517 struct w1_netlink_msg msg; 518 519 sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL); 520 if (!sl) { 521 dev_err(&dev->dev, 522 "%s: failed to allocate new slave device.\n", 523 __func__); 524 return -ENOMEM; 525 } 526 527 memset(sl, 0, sizeof(*sl)); 528 529 sl->owner = THIS_MODULE; 530 sl->master = dev; 531 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 532 533 memset(&msg, 0, sizeof(msg)); 534 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); 535 atomic_set(&sl->refcnt, 0); 536 init_completion(&sl->released); 537 538 spin_lock(&w1_flock); 539 f = w1_family_registered(rn->family); 540 if (!f) { 541 f= &w1_default_family; 542 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", 543 rn->family, rn->family, 544 (unsigned long long)rn->id, rn->crc); 545 } 546 __w1_family_get(f); 547 spin_unlock(&w1_flock); 548 549 sl->family = f; 550 551 552 err = __w1_attach_slave_device(sl); 553 if (err < 0) { 554 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, 555 sl->name); 556 w1_family_put(sl->family); 557 kfree(sl); 558 return err; 559 } 560 561 sl->ttl = dev->slave_ttl; 562 dev->slave_count++; 563 564 memcpy(msg.id.id, rn, sizeof(msg.id)); 565 msg.type = W1_SLAVE_ADD; 566 w1_netlink_send(dev, &msg); 567 568 return 0; 569 } 570 571 static void w1_slave_detach(struct w1_slave *sl) 572 { 573 struct w1_netlink_msg msg; 574 575 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl); 576 577 list_del(&sl->w1_slave_entry); 578 579 if (sl->family->fops && sl->family->fops->remove_slave) 580 sl->family->fops->remove_slave(sl); 581 582 memset(&msg, 0, sizeof(msg)); 583 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); 584 msg.type = W1_SLAVE_REMOVE; 585 w1_netlink_send(sl->master, &msg); 586 587 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 588 device_remove_file(&sl->dev, &w1_slave_attr_name); 589 device_unregister(&sl->dev); 590 591 wait_for_completion(&sl->released); 592 kfree(sl); 593 } 594 595 static struct w1_master *w1_search_master(void *data) 596 { 597 struct w1_master *dev; 598 int found = 0; 599 600 mutex_lock(&w1_mlock); 601 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 602 if (dev->bus_master->data == data) { 603 found = 1; 604 atomic_inc(&dev->refcnt); 605 break; 606 } 607 } 608 mutex_unlock(&w1_mlock); 609 610 return (found)?dev:NULL; 611 } 612 613 struct w1_master *w1_search_master_id(u32 id) 614 { 615 struct w1_master *dev; 616 int found = 0; 617 618 mutex_lock(&w1_mlock); 619 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 620 if (dev->id == id) { 621 found = 1; 622 atomic_inc(&dev->refcnt); 623 break; 624 } 625 } 626 mutex_unlock(&w1_mlock); 627 628 return (found)?dev:NULL; 629 } 630 631 struct w1_slave *w1_search_slave(struct w1_reg_num *id) 632 { 633 struct w1_master *dev; 634 struct w1_slave *sl = NULL; 635 int found = 0; 636 637 mutex_lock(&w1_mlock); 638 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 639 mutex_lock(&dev->mutex); 640 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 641 if (sl->reg_num.family == id->family && 642 sl->reg_num.id == id->id && 643 sl->reg_num.crc == id->crc) { 644 found = 1; 645 atomic_inc(&dev->refcnt); 646 atomic_inc(&sl->refcnt); 647 break; 648 } 649 } 650 mutex_unlock(&dev->mutex); 651 652 if (found) 653 break; 654 } 655 mutex_unlock(&w1_mlock); 656 657 return (found)?sl:NULL; 658 } 659 660 void w1_reconnect_slaves(struct w1_family *f) 661 { 662 struct w1_master *dev; 663 664 mutex_lock(&w1_mlock); 665 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 666 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n", 667 dev->name, f->fid); 668 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); 669 } 670 mutex_unlock(&w1_mlock); 671 } 672 673 static void w1_slave_found(void *data, u64 rn) 674 { 675 int slave_count; 676 struct w1_slave *sl; 677 struct list_head *ent; 678 struct w1_reg_num *tmp; 679 int family_found = 0; 680 struct w1_master *dev; 681 u64 rn_le = cpu_to_le64(rn); 682 683 dev = w1_search_master(data); 684 if (!dev) { 685 printk(KERN_ERR "Failed to find w1 master device for data %p, " 686 "it is impossible.\n", data); 687 return; 688 } 689 690 tmp = (struct w1_reg_num *) &rn; 691 692 slave_count = 0; 693 list_for_each(ent, &dev->slist) { 694 695 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 696 697 if (sl->reg_num.family == tmp->family && 698 sl->reg_num.id == tmp->id && 699 sl->reg_num.crc == tmp->crc) { 700 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 701 break; 702 } else if (sl->reg_num.family == tmp->family) { 703 family_found = 1; 704 break; 705 } 706 707 slave_count++; 708 } 709 710 if (slave_count == dev->slave_count && 711 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) { 712 w1_attach_slave_device(dev, tmp); 713 } 714 715 atomic_dec(&dev->refcnt); 716 } 717 718 /** 719 * Performs a ROM Search & registers any devices found. 720 * The 1-wire search is a simple binary tree search. 721 * For each bit of the address, we read two bits and write one bit. 722 * The bit written will put to sleep all devies that don't match that bit. 723 * When the two reads differ, the direction choice is obvious. 724 * When both bits are 0, we must choose a path to take. 725 * When we can scan all 64 bits without having to choose a path, we are done. 726 * 727 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com 728 * 729 * @dev The master device to search 730 * @cb Function to call when a device is found 731 */ 732 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) 733 { 734 u64 last_rn, rn, tmp64; 735 int i, slave_count = 0; 736 int last_zero, last_device; 737 int search_bit, desc_bit; 738 u8 triplet_ret = 0; 739 740 search_bit = 0; 741 rn = last_rn = 0; 742 last_device = 0; 743 last_zero = -1; 744 745 desc_bit = 64; 746 747 while ( !last_device && (slave_count++ < dev->max_slave_count) ) { 748 last_rn = rn; 749 rn = 0; 750 751 /* 752 * Reset bus and all 1-wire device state machines 753 * so they can respond to our requests. 754 * 755 * Return 0 - device(s) present, 1 - no devices present. 756 */ 757 if (w1_reset_bus(dev)) { 758 dev_dbg(&dev->dev, "No devices present on the wire.\n"); 759 break; 760 } 761 762 /* Start the search */ 763 w1_write_8(dev, search_type); 764 for (i = 0; i < 64; ++i) { 765 /* Determine the direction/search bit */ 766 if (i == desc_bit) 767 search_bit = 1; /* took the 0 path last time, so take the 1 path */ 768 else if (i > desc_bit) 769 search_bit = 0; /* take the 0 path on the next branch */ 770 else 771 search_bit = ((last_rn >> i) & 0x1); 772 773 /** Read two bits and write one bit */ 774 triplet_ret = w1_triplet(dev, search_bit); 775 776 /* quit if no device responded */ 777 if ( (triplet_ret & 0x03) == 0x03 ) 778 break; 779 780 /* If both directions were valid, and we took the 0 path... */ 781 if (triplet_ret == 0) 782 last_zero = i; 783 784 /* extract the direction taken & update the device number */ 785 tmp64 = (triplet_ret >> 2); 786 rn |= (tmp64 << i); 787 } 788 789 if ( (triplet_ret & 0x03) != 0x03 ) { 790 if ( (desc_bit == last_zero) || (last_zero < 0)) 791 last_device = 1; 792 desc_bit = last_zero; 793 cb(dev->bus_master->data, rn); 794 } 795 } 796 } 797 798 static int w1_control(void *data) 799 { 800 struct w1_slave *sl, *sln; 801 struct w1_master *dev, *n; 802 int have_to_wait = 0; 803 804 while (!kthread_should_stop() || have_to_wait) { 805 have_to_wait = 0; 806 807 try_to_freeze(); 808 msleep_interruptible(w1_control_timeout * 1000); 809 810 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) { 811 if (!kthread_should_stop() && !dev->flags) 812 continue; 813 /* 814 * Little race: we can create thread but not set the flag. 815 * Get a chance for external process to set flag up. 816 */ 817 if (!dev->initialized) { 818 have_to_wait = 1; 819 continue; 820 } 821 822 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 823 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 824 825 mutex_lock(&w1_mlock); 826 list_del(&dev->w1_master_entry); 827 mutex_unlock(&w1_mlock); 828 829 mutex_lock(&dev->mutex); 830 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 831 w1_slave_detach(sl); 832 } 833 w1_destroy_master_attributes(dev); 834 mutex_unlock(&dev->mutex); 835 atomic_dec(&dev->refcnt); 836 continue; 837 } 838 839 if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) { 840 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name); 841 mutex_lock(&dev->mutex); 842 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 843 if (sl->family->fid == W1_FAMILY_DEFAULT) { 844 struct w1_reg_num rn; 845 846 memcpy(&rn, &sl->reg_num, sizeof(rn)); 847 w1_slave_detach(sl); 848 849 w1_attach_slave_device(dev, &rn); 850 } 851 } 852 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name); 853 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); 854 mutex_unlock(&dev->mutex); 855 } 856 } 857 } 858 859 return 0; 860 } 861 862 void w1_search_process(struct w1_master *dev, u8 search_type) 863 { 864 struct w1_slave *sl, *sln; 865 866 list_for_each_entry(sl, &dev->slist, w1_slave_entry) 867 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 868 869 w1_search_devices(dev, search_type, w1_slave_found); 870 871 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 872 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) { 873 w1_slave_detach(sl); 874 875 dev->slave_count--; 876 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags)) 877 sl->ttl = dev->slave_ttl; 878 } 879 880 if (dev->search_count > 0) 881 dev->search_count--; 882 } 883 884 int w1_process(void *data) 885 { 886 struct w1_master *dev = (struct w1_master *) data; 887 888 while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 889 try_to_freeze(); 890 msleep_interruptible(w1_timeout * 1000); 891 892 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) 893 break; 894 895 if (!dev->initialized) 896 continue; 897 898 if (dev->search_count == 0) 899 continue; 900 901 mutex_lock(&dev->mutex); 902 w1_search_process(dev, W1_SEARCH); 903 mutex_unlock(&dev->mutex); 904 } 905 906 atomic_dec(&dev->refcnt); 907 908 return 0; 909 } 910 911 static int w1_init(void) 912 { 913 int retval; 914 915 printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n"); 916 917 w1_init_netlink(); 918 919 retval = bus_register(&w1_bus_type); 920 if (retval) { 921 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval); 922 goto err_out_exit_init; 923 } 924 925 retval = driver_register(&w1_master_driver); 926 if (retval) { 927 printk(KERN_ERR 928 "Failed to register master driver. err=%d.\n", 929 retval); 930 goto err_out_bus_unregister; 931 } 932 933 retval = driver_register(&w1_slave_driver); 934 if (retval) { 935 printk(KERN_ERR 936 "Failed to register master driver. err=%d.\n", 937 retval); 938 goto err_out_master_unregister; 939 } 940 941 w1_control_thread = kthread_run(w1_control, NULL, "w1_control"); 942 if (IS_ERR(w1_control_thread)) { 943 retval = PTR_ERR(w1_control_thread); 944 printk(KERN_ERR "Failed to create control thread. err=%d\n", 945 retval); 946 goto err_out_slave_unregister; 947 } 948 949 return 0; 950 951 err_out_slave_unregister: 952 driver_unregister(&w1_slave_driver); 953 954 err_out_master_unregister: 955 driver_unregister(&w1_master_driver); 956 957 err_out_bus_unregister: 958 bus_unregister(&w1_bus_type); 959 960 err_out_exit_init: 961 return retval; 962 } 963 964 static void w1_fini(void) 965 { 966 struct w1_master *dev; 967 968 list_for_each_entry(dev, &w1_masters, w1_master_entry) 969 __w1_remove_master_device(dev); 970 971 w1_fini_netlink(); 972 973 kthread_stop(w1_control_thread); 974 975 driver_unregister(&w1_slave_driver); 976 driver_unregister(&w1_master_driver); 977 bus_unregister(&w1_bus_type); 978 } 979 980 module_init(w1_init); 981 module_exit(w1_fini); 982