1/* 2 * w1.c 3 * 4 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> 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 <linux/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 <zbr@ioremap.net>"); 46MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); 47 48static int w1_timeout = 10; 49int w1_max_slave_count = 64; 50int w1_max_slave_ttl = 10; 51 52module_param_named(timeout, w1_timeout, int, 0); 53MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches"); 54/* A search stops when w1_max_slave_count devices have been found in that 55 * search. The next search will start over and detect the same set of devices 56 * on a static 1-wire bus. Memory is not allocated based on this number, just 57 * on the number of devices known to the kernel. Having a high number does not 58 * consume additional resources. As a special case, if there is only one 59 * device on the network and w1_max_slave_count is set to 1, the device id can 60 * be read directly skipping the normal slower search process. 61 */ 62module_param_named(max_slave_count, w1_max_slave_count, int, 0); 63MODULE_PARM_DESC(max_slave_count, 64 "maximum number of slaves detected in a search"); 65module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); 66MODULE_PARM_DESC(slave_ttl, 67 "Number of searches not seeing a slave before it will be removed"); 68 69DEFINE_MUTEX(w1_mlock); 70LIST_HEAD(w1_masters); 71 72static int w1_master_match(struct device *dev, struct device_driver *drv) 73{ 74 return 1; 75} 76 77static int w1_master_probe(struct device *dev) 78{ 79 return -ENODEV; 80} 81 82static void w1_master_release(struct device *dev) 83{ 84 struct w1_master *md = dev_to_w1_master(dev); 85 86 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); 87 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 88 kfree(md); 89} 90 91static void w1_slave_release(struct device *dev) 92{ 93 struct w1_slave *sl = dev_to_w1_slave(dev); 94 95 dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl); 96 97 w1_family_put(sl->family); 98 sl->master->slave_count--; 99} 100 101static ssize_t name_show(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} 107static DEVICE_ATTR_RO(name); 108 109static ssize_t id_show(struct device *dev, 110 struct device_attribute *attr, char *buf) 111{ 112 struct w1_slave *sl = dev_to_w1_slave(dev); 113 ssize_t count = sizeof(sl->reg_num); 114 115 memcpy(buf, (u8 *)&sl->reg_num, count); 116 return count; 117} 118static DEVICE_ATTR_RO(id); 119 120static struct attribute *w1_slave_attrs[] = { 121 &dev_attr_name.attr, 122 &dev_attr_id.attr, 123 NULL, 124}; 125ATTRIBUTE_GROUPS(w1_slave); 126 127/* Default family */ 128 129static ssize_t rw_write(struct file *filp, struct kobject *kobj, 130 struct bin_attribute *bin_attr, char *buf, loff_t off, 131 size_t count) 132{ 133 struct w1_slave *sl = kobj_to_w1_slave(kobj); 134 135 mutex_lock(&sl->master->mutex); 136 if (w1_reset_select_slave(sl)) { 137 count = 0; 138 goto out_up; 139 } 140 141 w1_write_block(sl->master, buf, count); 142 143out_up: 144 mutex_unlock(&sl->master->mutex); 145 return count; 146} 147 148static ssize_t rw_read(struct file *filp, struct kobject *kobj, 149 struct bin_attribute *bin_attr, char *buf, loff_t off, 150 size_t count) 151{ 152 struct w1_slave *sl = kobj_to_w1_slave(kobj); 153 154 mutex_lock(&sl->master->mutex); 155 w1_read_block(sl->master, buf, count); 156 mutex_unlock(&sl->master->mutex); 157 return count; 158} 159 160static BIN_ATTR_RW(rw, PAGE_SIZE); 161 162static struct bin_attribute *w1_slave_bin_attrs[] = { 163 &bin_attr_rw, 164 NULL, 165}; 166 167static const struct attribute_group w1_slave_default_group = { 168 .bin_attrs = w1_slave_bin_attrs, 169}; 170 171static const struct attribute_group *w1_slave_default_groups[] = { 172 &w1_slave_default_group, 173 NULL, 174}; 175 176static struct w1_family_ops w1_default_fops = { 177 .groups = w1_slave_default_groups, 178}; 179 180static struct w1_family w1_default_family = { 181 .fops = &w1_default_fops, 182}; 183 184static int w1_uevent(struct device *dev, struct kobj_uevent_env *env); 185 186static struct bus_type w1_bus_type = { 187 .name = "w1", 188 .match = w1_master_match, 189 .uevent = w1_uevent, 190}; 191 192struct device_driver w1_master_driver = { 193 .name = "w1_master_driver", 194 .bus = &w1_bus_type, 195 .probe = w1_master_probe, 196}; 197 198struct device w1_master_device = { 199 .parent = NULL, 200 .bus = &w1_bus_type, 201 .init_name = "w1 bus master", 202 .driver = &w1_master_driver, 203 .release = &w1_master_release 204}; 205 206static struct device_driver w1_slave_driver = { 207 .name = "w1_slave_driver", 208 .bus = &w1_bus_type, 209}; 210 211#if 0 212struct device w1_slave_device = { 213 .parent = NULL, 214 .bus = &w1_bus_type, 215 .init_name = "w1 bus slave", 216 .driver = &w1_slave_driver, 217 .release = &w1_slave_release 218}; 219#endif /* 0 */ 220 221static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) 222{ 223 struct w1_master *md = dev_to_w1_master(dev); 224 ssize_t count; 225 226 mutex_lock(&md->mutex); 227 count = sprintf(buf, "%s\n", md->name); 228 mutex_unlock(&md->mutex); 229 230 return count; 231} 232 233static ssize_t w1_master_attribute_store_search(struct device * dev, 234 struct device_attribute *attr, 235 const char * buf, size_t count) 236{ 237 long tmp; 238 struct w1_master *md = dev_to_w1_master(dev); 239 int ret; 240 241 ret = kstrtol(buf, 0, &tmp); 242 if (ret) 243 return ret; 244 245 mutex_lock(&md->mutex); 246 md->search_count = tmp; 247 mutex_unlock(&md->mutex); 248 /* Only wake if it is going to be searching. */ 249 if (tmp) 250 wake_up_process(md->thread); 251 252 return count; 253} 254 255static ssize_t w1_master_attribute_show_search(struct device *dev, 256 struct device_attribute *attr, 257 char *buf) 258{ 259 struct w1_master *md = dev_to_w1_master(dev); 260 ssize_t count; 261 262 mutex_lock(&md->mutex); 263 count = sprintf(buf, "%d\n", md->search_count); 264 mutex_unlock(&md->mutex); 265 266 return count; 267} 268 269static ssize_t w1_master_attribute_store_pullup(struct device *dev, 270 struct device_attribute *attr, 271 const char *buf, size_t count) 272{ 273 long tmp; 274 struct w1_master *md = dev_to_w1_master(dev); 275 int ret; 276 277 ret = kstrtol(buf, 0, &tmp); 278 if (ret) 279 return ret; 280 281 mutex_lock(&md->mutex); 282 md->enable_pullup = tmp; 283 mutex_unlock(&md->mutex); 284 285 return count; 286} 287 288static ssize_t w1_master_attribute_show_pullup(struct device *dev, 289 struct device_attribute *attr, 290 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->enable_pullup); 297 mutex_unlock(&md->mutex); 298 299 return count; 300} 301 302static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) 303{ 304 struct w1_master *md = dev_to_w1_master(dev); 305 ssize_t count; 306 307 mutex_lock(&md->mutex); 308 count = sprintf(buf, "0x%p\n", md->bus_master); 309 mutex_unlock(&md->mutex); 310 return count; 311} 312 313static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) 314{ 315 ssize_t count; 316 count = sprintf(buf, "%d\n", w1_timeout); 317 return count; 318} 319 320static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev, 321 struct device_attribute *attr, const char *buf, size_t count) 322{ 323 int tmp; 324 struct w1_master *md = dev_to_w1_master(dev); 325 326 if (kstrtoint(buf, 0, &tmp) == -EINVAL || tmp < 1) 327 return -EINVAL; 328 329 mutex_lock(&md->mutex); 330 md->max_slave_count = tmp; 331 /* allow each time the max_slave_count is updated */ 332 clear_bit(W1_WARN_MAX_COUNT, &md->flags); 333 mutex_unlock(&md->mutex); 334 335 return count; 336} 337 338static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 339{ 340 struct w1_master *md = dev_to_w1_master(dev); 341 ssize_t count; 342 343 mutex_lock(&md->mutex); 344 count = sprintf(buf, "%d\n", md->max_slave_count); 345 mutex_unlock(&md->mutex); 346 return count; 347} 348 349static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) 350{ 351 struct w1_master *md = dev_to_w1_master(dev); 352 ssize_t count; 353 354 mutex_lock(&md->mutex); 355 count = sprintf(buf, "%lu\n", md->attempts); 356 mutex_unlock(&md->mutex); 357 return count; 358} 359 360static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 361{ 362 struct w1_master *md = dev_to_w1_master(dev); 363 ssize_t count; 364 365 mutex_lock(&md->mutex); 366 count = sprintf(buf, "%d\n", md->slave_count); 367 mutex_unlock(&md->mutex); 368 return count; 369} 370 371static ssize_t w1_master_attribute_show_slaves(struct device *dev, 372 struct device_attribute *attr, char *buf) 373{ 374 struct w1_master *md = dev_to_w1_master(dev); 375 int c = PAGE_SIZE; 376 struct list_head *ent, *n; 377 struct w1_slave *sl = NULL; 378 379 mutex_lock(&md->list_mutex); 380 381 list_for_each_safe(ent, n, &md->slist) { 382 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 383 384 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); 385 } 386 if (!sl) 387 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); 388 389 mutex_unlock(&md->list_mutex); 390 391 return PAGE_SIZE - c; 392} 393 394static ssize_t w1_master_attribute_show_add(struct device *dev, 395 struct device_attribute *attr, char *buf) 396{ 397 int c = PAGE_SIZE; 398 c -= snprintf(buf+PAGE_SIZE - c, c, 399 "write device id xx-xxxxxxxxxxxx to add slave\n"); 400 return PAGE_SIZE - c; 401} 402 403static int w1_atoreg_num(struct device *dev, const char *buf, size_t count, 404 struct w1_reg_num *rn) 405{ 406 unsigned int family; 407 unsigned long long id; 408 int i; 409 u64 rn64_le; 410 411 /* The CRC value isn't read from the user because the sysfs directory 412 * doesn't include it and most messages from the bus search don't 413 * print it either. It would be unreasonable for the user to then 414 * provide it. 415 */ 416 const char *error_msg = "bad slave string format, expecting " 417 "ff-dddddddddddd\n"; 418 419 if (buf[2] != '-') { 420 dev_err(dev, "%s", error_msg); 421 return -EINVAL; 422 } 423 i = sscanf(buf, "%02x-%012llx", &family, &id); 424 if (i != 2) { 425 dev_err(dev, "%s", error_msg); 426 return -EINVAL; 427 } 428 rn->family = family; 429 rn->id = id; 430 431 rn64_le = cpu_to_le64(*(u64 *)rn); 432 rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7); 433 434#if 0 435 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n", 436 rn->family, (unsigned long long)rn->id, rn->crc); 437#endif 438 439 return 0; 440} 441 442/* Searches the slaves in the w1_master and returns a pointer or NULL. 443 * Note: must not hold list_mutex 444 */ 445struct w1_slave *w1_slave_search_device(struct w1_master *dev, 446 struct w1_reg_num *rn) 447{ 448 struct w1_slave *sl; 449 mutex_lock(&dev->list_mutex); 450 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 451 if (sl->reg_num.family == rn->family && 452 sl->reg_num.id == rn->id && 453 sl->reg_num.crc == rn->crc) { 454 mutex_unlock(&dev->list_mutex); 455 return sl; 456 } 457 } 458 mutex_unlock(&dev->list_mutex); 459 return NULL; 460} 461 462static ssize_t w1_master_attribute_store_add(struct device *dev, 463 struct device_attribute *attr, 464 const char *buf, size_t count) 465{ 466 struct w1_master *md = dev_to_w1_master(dev); 467 struct w1_reg_num rn; 468 struct w1_slave *sl; 469 ssize_t result = count; 470 471 if (w1_atoreg_num(dev, buf, count, &rn)) 472 return -EINVAL; 473 474 mutex_lock(&md->mutex); 475 sl = w1_slave_search_device(md, &rn); 476 /* It would be nice to do a targeted search one the one-wire bus 477 * for the new device to see if it is out there or not. But the 478 * current search doesn't support that. 479 */ 480 if (sl) { 481 dev_info(dev, "Device %s already exists\n", sl->name); 482 result = -EINVAL; 483 } else { 484 w1_attach_slave_device(md, &rn); 485 } 486 mutex_unlock(&md->mutex); 487 488 return result; 489} 490 491static ssize_t w1_master_attribute_show_remove(struct device *dev, 492 struct device_attribute *attr, char *buf) 493{ 494 int c = PAGE_SIZE; 495 c -= snprintf(buf+PAGE_SIZE - c, c, 496 "write device id xx-xxxxxxxxxxxx to remove slave\n"); 497 return PAGE_SIZE - c; 498} 499 500static ssize_t w1_master_attribute_store_remove(struct device *dev, 501 struct device_attribute *attr, 502 const char *buf, size_t count) 503{ 504 struct w1_master *md = dev_to_w1_master(dev); 505 struct w1_reg_num rn; 506 struct w1_slave *sl; 507 ssize_t result = count; 508 509 if (w1_atoreg_num(dev, buf, count, &rn)) 510 return -EINVAL; 511 512 mutex_lock(&md->mutex); 513 sl = w1_slave_search_device(md, &rn); 514 if (sl) { 515 result = w1_slave_detach(sl); 516 /* refcnt 0 means it was detached in the call */ 517 if (result == 0) 518 result = count; 519 } else { 520 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family, 521 (unsigned long long)rn.id); 522 result = -EINVAL; 523 } 524 mutex_unlock(&md->mutex); 525 526 return result; 527} 528 529#define W1_MASTER_ATTR_RO(_name, _mode) \ 530 struct device_attribute w1_master_attribute_##_name = \ 531 __ATTR(w1_master_##_name, _mode, \ 532 w1_master_attribute_show_##_name, NULL) 533 534#define W1_MASTER_ATTR_RW(_name, _mode) \ 535 struct device_attribute w1_master_attribute_##_name = \ 536 __ATTR(w1_master_##_name, _mode, \ 537 w1_master_attribute_show_##_name, \ 538 w1_master_attribute_store_##_name) 539 540static W1_MASTER_ATTR_RO(name, S_IRUGO); 541static W1_MASTER_ATTR_RO(slaves, S_IRUGO); 542static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); 543static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP); 544static W1_MASTER_ATTR_RO(attempts, S_IRUGO); 545static W1_MASTER_ATTR_RO(timeout, S_IRUGO); 546static W1_MASTER_ATTR_RO(pointer, S_IRUGO); 547static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP); 548static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP); 549static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP); 550static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP); 551 552static struct attribute *w1_master_default_attrs[] = { 553 &w1_master_attribute_name.attr, 554 &w1_master_attribute_slaves.attr, 555 &w1_master_attribute_slave_count.attr, 556 &w1_master_attribute_max_slave_count.attr, 557 &w1_master_attribute_attempts.attr, 558 &w1_master_attribute_timeout.attr, 559 &w1_master_attribute_pointer.attr, 560 &w1_master_attribute_search.attr, 561 &w1_master_attribute_pullup.attr, 562 &w1_master_attribute_add.attr, 563 &w1_master_attribute_remove.attr, 564 NULL 565}; 566 567static struct attribute_group w1_master_defattr_group = { 568 .attrs = w1_master_default_attrs, 569}; 570 571int w1_create_master_attributes(struct w1_master *master) 572{ 573 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); 574} 575 576void w1_destroy_master_attributes(struct w1_master *master) 577{ 578 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); 579} 580 581static int w1_uevent(struct device *dev, struct kobj_uevent_env *env) 582{ 583 struct w1_master *md = NULL; 584 struct w1_slave *sl = NULL; 585 char *event_owner, *name; 586 int err = 0; 587 588 if (dev->driver == &w1_master_driver) { 589 md = container_of(dev, struct w1_master, dev); 590 event_owner = "master"; 591 name = md->name; 592 } else if (dev->driver == &w1_slave_driver) { 593 sl = container_of(dev, struct w1_slave, dev); 594 event_owner = "slave"; 595 name = sl->name; 596 } else { 597 dev_dbg(dev, "Unknown event.\n"); 598 return -EINVAL; 599 } 600 601 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", 602 event_owner, name, dev_name(dev)); 603 604 if (dev->driver != &w1_slave_driver || !sl) 605 goto end; 606 607 err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family); 608 if (err) 609 goto end; 610 611 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX", 612 (unsigned long long)sl->reg_num.id); 613end: 614 return err; 615} 616 617static int w1_family_notify(unsigned long action, struct w1_slave *sl) 618{ 619 struct w1_family_ops *fops; 620 int err; 621 622 fops = sl->family->fops; 623 624 if (!fops) 625 return 0; 626 627 switch (action) { 628 case BUS_NOTIFY_ADD_DEVICE: 629 /* if the family driver needs to initialize something... */ 630 if (fops->add_slave) { 631 err = fops->add_slave(sl); 632 if (err < 0) { 633 dev_err(&sl->dev, 634 "add_slave() call failed. err=%d\n", 635 err); 636 return err; 637 } 638 } 639 if (fops->groups) { 640 err = sysfs_create_groups(&sl->dev.kobj, fops->groups); 641 if (err) { 642 dev_err(&sl->dev, 643 "sysfs group creation failed. err=%d\n", 644 err); 645 return err; 646 } 647 } 648 649 break; 650 case BUS_NOTIFY_DEL_DEVICE: 651 if (fops->remove_slave) 652 sl->family->fops->remove_slave(sl); 653 if (fops->groups) 654 sysfs_remove_groups(&sl->dev.kobj, fops->groups); 655 break; 656 } 657 return 0; 658} 659 660static int __w1_attach_slave_device(struct w1_slave *sl) 661{ 662 int err; 663 664 sl->dev.parent = &sl->master->dev; 665 sl->dev.driver = &w1_slave_driver; 666 sl->dev.bus = &w1_bus_type; 667 sl->dev.release = &w1_slave_release; 668 sl->dev.groups = w1_slave_groups; 669 670 dev_set_name(&sl->dev, "%02x-%012llx", 671 (unsigned int) sl->reg_num.family, 672 (unsigned long long) sl->reg_num.id); 673 snprintf(&sl->name[0], sizeof(sl->name), 674 "%02x-%012llx", 675 (unsigned int) sl->reg_num.family, 676 (unsigned long long) sl->reg_num.id); 677 678 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, 679 dev_name(&sl->dev), sl); 680 681 /* suppress for w1_family_notify before sending KOBJ_ADD */ 682 dev_set_uevent_suppress(&sl->dev, true); 683 684 err = device_register(&sl->dev); 685 if (err < 0) { 686 dev_err(&sl->dev, 687 "Device registration [%s] failed. err=%d\n", 688 dev_name(&sl->dev), err); 689 return err; 690 } 691 w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl); 692 693 dev_set_uevent_suppress(&sl->dev, false); 694 kobject_uevent(&sl->dev.kobj, KOBJ_ADD); 695 696 mutex_lock(&sl->master->list_mutex); 697 list_add_tail(&sl->w1_slave_entry, &sl->master->slist); 698 mutex_unlock(&sl->master->list_mutex); 699 700 return 0; 701} 702 703int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 704{ 705 struct w1_slave *sl; 706 struct w1_family *f; 707 int err; 708 struct w1_netlink_msg msg; 709 710 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL); 711 if (!sl) { 712 dev_err(&dev->dev, 713 "%s: failed to allocate new slave device.\n", 714 __func__); 715 return -ENOMEM; 716 } 717 718 719 sl->owner = THIS_MODULE; 720 sl->master = dev; 721 set_bit(W1_SLAVE_ACTIVE, &sl->flags); 722 723 memset(&msg, 0, sizeof(msg)); 724 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); 725 atomic_set(&sl->refcnt, 1); 726 atomic_inc(&sl->master->refcnt); 727 728 /* slave modules need to be loaded in a context with unlocked mutex */ 729 mutex_unlock(&dev->mutex); 730 request_module("w1-family-0x%02x", rn->family); 731 mutex_lock(&dev->mutex); 732 733 spin_lock(&w1_flock); 734 f = w1_family_registered(rn->family); 735 if (!f) { 736 f= &w1_default_family; 737 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", 738 rn->family, rn->family, 739 (unsigned long long)rn->id, rn->crc); 740 } 741 __w1_family_get(f); 742 spin_unlock(&w1_flock); 743 744 sl->family = f; 745 746 747 err = __w1_attach_slave_device(sl); 748 if (err < 0) { 749 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, 750 sl->name); 751 w1_family_put(sl->family); 752 kfree(sl); 753 return err; 754 } 755 756 sl->ttl = dev->slave_ttl; 757 dev->slave_count++; 758 759 memcpy(msg.id.id, rn, sizeof(msg.id)); 760 msg.type = W1_SLAVE_ADD; 761 w1_netlink_send(dev, &msg); 762 763 return 0; 764} 765 766int w1_unref_slave(struct w1_slave *sl) 767{ 768 struct w1_master *dev = sl->master; 769 int refcnt; 770 mutex_lock(&dev->list_mutex); 771 refcnt = atomic_sub_return(1, &sl->refcnt); 772 if (refcnt == 0) { 773 struct w1_netlink_msg msg; 774 775 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, 776 sl->name, sl); 777 778 list_del(&sl->w1_slave_entry); 779 780 memset(&msg, 0, sizeof(msg)); 781 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); 782 msg.type = W1_SLAVE_REMOVE; 783 w1_netlink_send(sl->master, &msg); 784 785 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl); 786 device_unregister(&sl->dev); 787 #ifdef DEBUG 788 memset(sl, 0, sizeof(*sl)); 789 #endif 790 kfree(sl); 791 } 792 atomic_dec(&dev->refcnt); 793 mutex_unlock(&dev->list_mutex); 794 return refcnt; 795} 796 797int w1_slave_detach(struct w1_slave *sl) 798{ 799 /* Only detach a slave once as it decreases the refcnt each time. */ 800 int destroy_now; 801 mutex_lock(&sl->master->list_mutex); 802 destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags); 803 set_bit(W1_SLAVE_DETACH, &sl->flags); 804 mutex_unlock(&sl->master->list_mutex); 805 806 if (destroy_now) 807 destroy_now = !w1_unref_slave(sl); 808 return destroy_now ? 0 : -EBUSY; 809} 810 811struct w1_master *w1_search_master_id(u32 id) 812{ 813 struct w1_master *dev; 814 int found = 0; 815 816 mutex_lock(&w1_mlock); 817 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 818 if (dev->id == id) { 819 found = 1; 820 atomic_inc(&dev->refcnt); 821 break; 822 } 823 } 824 mutex_unlock(&w1_mlock); 825 826 return (found)?dev:NULL; 827} 828 829struct w1_slave *w1_search_slave(struct w1_reg_num *id) 830{ 831 struct w1_master *dev; 832 struct w1_slave *sl = NULL; 833 int found = 0; 834 835 mutex_lock(&w1_mlock); 836 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 837 mutex_lock(&dev->list_mutex); 838 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 839 if (sl->reg_num.family == id->family && 840 sl->reg_num.id == id->id && 841 sl->reg_num.crc == id->crc) { 842 found = 1; 843 atomic_inc(&dev->refcnt); 844 atomic_inc(&sl->refcnt); 845 break; 846 } 847 } 848 mutex_unlock(&dev->list_mutex); 849 850 if (found) 851 break; 852 } 853 mutex_unlock(&w1_mlock); 854 855 return (found)?sl:NULL; 856} 857 858void w1_reconnect_slaves(struct w1_family *f, int attach) 859{ 860 struct w1_slave *sl, *sln; 861 struct w1_master *dev; 862 863 mutex_lock(&w1_mlock); 864 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 865 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 866 "for family %02x.\n", dev->name, f->fid); 867 mutex_lock(&dev->mutex); 868 mutex_lock(&dev->list_mutex); 869 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 870 /* If it is a new family, slaves with the default 871 * family driver and are that family will be 872 * connected. If the family is going away, devices 873 * matching that family are reconneced. 874 */ 875 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT 876 && sl->reg_num.family == f->fid) || 877 (!attach && sl->family->fid == f->fid)) { 878 struct w1_reg_num rn; 879 880 mutex_unlock(&dev->list_mutex); 881 memcpy(&rn, &sl->reg_num, sizeof(rn)); 882 /* If it was already in use let the automatic 883 * scan pick it up again later. 884 */ 885 if (!w1_slave_detach(sl)) 886 w1_attach_slave_device(dev, &rn); 887 mutex_lock(&dev->list_mutex); 888 } 889 } 890 dev_dbg(&dev->dev, "Reconnecting slaves in device %s " 891 "has been finished.\n", dev->name); 892 mutex_unlock(&dev->list_mutex); 893 mutex_unlock(&dev->mutex); 894 } 895 mutex_unlock(&w1_mlock); 896} 897 898void w1_slave_found(struct w1_master *dev, u64 rn) 899{ 900 struct w1_slave *sl; 901 struct w1_reg_num *tmp; 902 u64 rn_le = cpu_to_le64(rn); 903 904 atomic_inc(&dev->refcnt); 905 906 tmp = (struct w1_reg_num *) &rn; 907 908 sl = w1_slave_search_device(dev, tmp); 909 if (sl) { 910 set_bit(W1_SLAVE_ACTIVE, &sl->flags); 911 } else { 912 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7)) 913 w1_attach_slave_device(dev, tmp); 914 } 915 916 atomic_dec(&dev->refcnt); 917} 918 919/** 920 * w1_search() - Performs a ROM Search & registers any devices found. 921 * @dev: The master device to search 922 * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH 923 * to return only devices in the alarmed state 924 * @cb: Function to call when a device is found 925 * 926 * The 1-wire search is a simple binary tree search. 927 * For each bit of the address, we read two bits and write one bit. 928 * The bit written will put to sleep all devies that don't match that bit. 929 * When the two reads differ, the direction choice is obvious. 930 * When both bits are 0, we must choose a path to take. 931 * When we can scan all 64 bits without having to choose a path, we are done. 932 * 933 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com 934 * 935 */ 936void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) 937{ 938 u64 last_rn, rn, tmp64; 939 int i, slave_count = 0; 940 int last_zero, last_device; 941 int search_bit, desc_bit; 942 u8 triplet_ret = 0; 943 944 search_bit = 0; 945 rn = dev->search_id; 946 last_rn = 0; 947 last_device = 0; 948 last_zero = -1; 949 950 desc_bit = 64; 951 952 while ( !last_device && (slave_count++ < dev->max_slave_count) ) { 953 last_rn = rn; 954 rn = 0; 955 956 /* 957 * Reset bus and all 1-wire device state machines 958 * so they can respond to our requests. 959 * 960 * Return 0 - device(s) present, 1 - no devices present. 961 */ 962 mutex_lock(&dev->bus_mutex); 963 if (w1_reset_bus(dev)) { 964 mutex_unlock(&dev->bus_mutex); 965 dev_dbg(&dev->dev, "No devices present on the wire.\n"); 966 break; 967 } 968 969 /* Do fast search on single slave bus */ 970 if (dev->max_slave_count == 1) { 971 int rv; 972 w1_write_8(dev, W1_READ_ROM); 973 rv = w1_read_block(dev, (u8 *)&rn, 8); 974 mutex_unlock(&dev->bus_mutex); 975 976 if (rv == 8 && rn) 977 cb(dev, rn); 978 979 break; 980 } 981 982 /* Start the search */ 983 w1_write_8(dev, search_type); 984 for (i = 0; i < 64; ++i) { 985 /* Determine the direction/search bit */ 986 if (i == desc_bit) 987 search_bit = 1; /* took the 0 path last time, so take the 1 path */ 988 else if (i > desc_bit) 989 search_bit = 0; /* take the 0 path on the next branch */ 990 else 991 search_bit = ((last_rn >> i) & 0x1); 992 993 /* Read two bits and write one bit */ 994 triplet_ret = w1_triplet(dev, search_bit); 995 996 /* quit if no device responded */ 997 if ( (triplet_ret & 0x03) == 0x03 ) 998 break; 999 1000 /* If both directions were valid, and we took the 0 path... */ 1001 if (triplet_ret == 0) 1002 last_zero = i; 1003 1004 /* extract the direction taken & update the device number */ 1005 tmp64 = (triplet_ret >> 2); 1006 rn |= (tmp64 << i); 1007 1008 if (test_bit(W1_ABORT_SEARCH, &dev->flags)) { 1009 mutex_unlock(&dev->bus_mutex); 1010 dev_dbg(&dev->dev, "Abort w1_search\n"); 1011 return; 1012 } 1013 } 1014 mutex_unlock(&dev->bus_mutex); 1015 1016 if ( (triplet_ret & 0x03) != 0x03 ) { 1017 if ((desc_bit == last_zero) || (last_zero < 0)) { 1018 last_device = 1; 1019 dev->search_id = 0; 1020 } else { 1021 dev->search_id = rn; 1022 } 1023 desc_bit = last_zero; 1024 cb(dev, rn); 1025 } 1026 1027 if (!last_device && slave_count == dev->max_slave_count && 1028 !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) { 1029 /* Only max_slave_count will be scanned in a search, 1030 * but it will start where it left off next search 1031 * until all ids are identified and then it will start 1032 * over. A continued search will report the previous 1033 * last id as the first id (provided it is still on the 1034 * bus). 1035 */ 1036 dev_info(&dev->dev, "%s: max_slave_count %d reached, " 1037 "will continue next search.\n", __func__, 1038 dev->max_slave_count); 1039 set_bit(W1_WARN_MAX_COUNT, &dev->flags); 1040 } 1041 } 1042} 1043 1044void w1_search_process_cb(struct w1_master *dev, u8 search_type, 1045 w1_slave_found_callback cb) 1046{ 1047 struct w1_slave *sl, *sln; 1048 1049 mutex_lock(&dev->list_mutex); 1050 list_for_each_entry(sl, &dev->slist, w1_slave_entry) 1051 clear_bit(W1_SLAVE_ACTIVE, &sl->flags); 1052 mutex_unlock(&dev->list_mutex); 1053 1054 w1_search_devices(dev, search_type, cb); 1055 1056 mutex_lock(&dev->list_mutex); 1057 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 1058 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) { 1059 mutex_unlock(&dev->list_mutex); 1060 w1_slave_detach(sl); 1061 mutex_lock(&dev->list_mutex); 1062 } 1063 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags)) 1064 sl->ttl = dev->slave_ttl; 1065 } 1066 mutex_unlock(&dev->list_mutex); 1067 1068 if (dev->search_count > 0) 1069 dev->search_count--; 1070} 1071 1072static void w1_search_process(struct w1_master *dev, u8 search_type) 1073{ 1074 w1_search_process_cb(dev, search_type, w1_slave_found); 1075} 1076 1077/** 1078 * w1_process_callbacks() - execute each dev->async_list callback entry 1079 * @dev: w1_master device 1080 * 1081 * The w1 master list_mutex must be held. 1082 * 1083 * Return: 1 if there were commands to executed 0 otherwise 1084 */ 1085int w1_process_callbacks(struct w1_master *dev) 1086{ 1087 int ret = 0; 1088 struct w1_async_cmd *async_cmd, *async_n; 1089 1090 /* The list can be added to in another thread, loop until it is empty */ 1091 while (!list_empty(&dev->async_list)) { 1092 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list, 1093 async_entry) { 1094 /* drop the lock, if it is a search it can take a long 1095 * time */ 1096 mutex_unlock(&dev->list_mutex); 1097 async_cmd->cb(dev, async_cmd); 1098 ret = 1; 1099 mutex_lock(&dev->list_mutex); 1100 } 1101 } 1102 return ret; 1103} 1104 1105int w1_process(void *data) 1106{ 1107 struct w1_master *dev = (struct w1_master *) data; 1108 /* As long as w1_timeout is only set by a module parameter the sleep 1109 * time can be calculated in jiffies once. 1110 */ 1111 const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000); 1112 /* remainder if it woke up early */ 1113 unsigned long jremain = 0; 1114 1115 for (;;) { 1116 1117 if (!jremain && dev->search_count) { 1118 mutex_lock(&dev->mutex); 1119 w1_search_process(dev, W1_SEARCH); 1120 mutex_unlock(&dev->mutex); 1121 } 1122 1123 mutex_lock(&dev->list_mutex); 1124 /* Note, w1_process_callback drops the lock while processing, 1125 * but locks it again before returning. 1126 */ 1127 if (!w1_process_callbacks(dev) && jremain) { 1128 /* a wake up is either to stop the thread, process 1129 * callbacks, or search, it isn't process callbacks, so 1130 * schedule a search. 1131 */ 1132 jremain = 1; 1133 } 1134 1135 try_to_freeze(); 1136 __set_current_state(TASK_INTERRUPTIBLE); 1137 1138 /* hold list_mutex until after interruptible to prevent loosing 1139 * the wakeup signal when async_cmd is added. 1140 */ 1141 mutex_unlock(&dev->list_mutex); 1142 1143 if (kthread_should_stop()) 1144 break; 1145 1146 /* Only sleep when the search is active. */ 1147 if (dev->search_count) { 1148 if (!jremain) 1149 jremain = jtime; 1150 jremain = schedule_timeout(jremain); 1151 } 1152 else 1153 schedule(); 1154 } 1155 1156 atomic_dec(&dev->refcnt); 1157 1158 return 0; 1159} 1160 1161static int __init w1_init(void) 1162{ 1163 int retval; 1164 1165 pr_info("Driver for 1-wire Dallas network protocol.\n"); 1166 1167 w1_init_netlink(); 1168 1169 retval = bus_register(&w1_bus_type); 1170 if (retval) { 1171 pr_err("Failed to register bus. err=%d.\n", retval); 1172 goto err_out_exit_init; 1173 } 1174 1175 retval = driver_register(&w1_master_driver); 1176 if (retval) { 1177 pr_err("Failed to register master driver. err=%d.\n", 1178 retval); 1179 goto err_out_bus_unregister; 1180 } 1181 1182 retval = driver_register(&w1_slave_driver); 1183 if (retval) { 1184 pr_err("Failed to register slave driver. err=%d.\n", 1185 retval); 1186 goto err_out_master_unregister; 1187 } 1188 1189 return 0; 1190 1191#if 0 1192/* For undoing the slave register if there was a step after it. */ 1193err_out_slave_unregister: 1194 driver_unregister(&w1_slave_driver); 1195#endif 1196 1197err_out_master_unregister: 1198 driver_unregister(&w1_master_driver); 1199 1200err_out_bus_unregister: 1201 bus_unregister(&w1_bus_type); 1202 1203err_out_exit_init: 1204 return retval; 1205} 1206 1207static void __exit w1_fini(void) 1208{ 1209 struct w1_master *dev; 1210 1211 /* Set netlink removal messages and some cleanup */ 1212 list_for_each_entry(dev, &w1_masters, w1_master_entry) 1213 __w1_remove_master_device(dev); 1214 1215 w1_fini_netlink(); 1216 1217 driver_unregister(&w1_slave_driver); 1218 driver_unregister(&w1_master_driver); 1219 bus_unregister(&w1_bus_type); 1220} 1221 1222module_init(w1_init); 1223module_exit(w1_fini); 1224