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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>4 */5 6#include <linux/delay.h>7#include <linux/kernel.h>8#include <linux/module.h>9#include <linux/moduleparam.h>10#include <linux/list.h>11#include <linux/interrupt.h>12#include <linux/spinlock.h>13#include <linux/timer.h>14#include <linux/device.h>15#include <linux/slab.h>16#include <linux/sched.h>17#include <linux/kthread.h>18#include <linux/freezer.h>19#include <linux/hwmon.h>20#include <linux/of.h>21 22#include <linux/atomic.h>23 24#include "w1_internal.h"25#include "w1_netlink.h"26 27#define W1_FAMILY_DEFAULT 028#define W1_FAMILY_DS28E04 0x1C /* for crc quirk */29 30 31static int w1_timeout = 10;32module_param_named(timeout, w1_timeout, int, 0);33MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");34 35static int w1_timeout_us;36module_param_named(timeout_us, w1_timeout_us, int, 0);37MODULE_PARM_DESC(timeout_us,38 "time in microseconds between automatic slave searches");39 40/* A search stops when w1_max_slave_count devices have been found in that41 * search. The next search will start over and detect the same set of devices42 * on a static 1-wire bus. Memory is not allocated based on this number, just43 * on the number of devices known to the kernel. Having a high number does not44 * consume additional resources. As a special case, if there is only one45 * device on the network and w1_max_slave_count is set to 1, the device id can46 * be read directly skipping the normal slower search process.47 */48int w1_max_slave_count = 64;49module_param_named(max_slave_count, w1_max_slave_count, int, 0);50MODULE_PARM_DESC(max_slave_count,51 "maximum number of slaves detected in a search");52 53int w1_max_slave_ttl = 10;54module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);55MODULE_PARM_DESC(slave_ttl,56 "Number of searches not seeing a slave before it will be removed");57 58DEFINE_MUTEX(w1_mlock);59LIST_HEAD(w1_masters);60 61static int w1_master_probe(struct device *dev)62{63 return -ENODEV;64}65 66static void w1_master_release(struct device *dev)67{68 struct w1_master *md = dev_to_w1_master(dev);69 70 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);71 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));72 kfree(md);73}74 75static void w1_slave_release(struct device *dev)76{77 struct w1_slave *sl = dev_to_w1_slave(dev);78 79 dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);80 81 w1_family_put(sl->family);82 sl->master->slave_count--;83}84 85static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)86{87 struct w1_slave *sl = dev_to_w1_slave(dev);88 89 return sprintf(buf, "%s\n", sl->name);90}91static DEVICE_ATTR_RO(name);92 93static ssize_t id_show(struct device *dev,94 struct device_attribute *attr, char *buf)95{96 struct w1_slave *sl = dev_to_w1_slave(dev);97 ssize_t count = sizeof(sl->reg_num);98 99 memcpy(buf, (u8 *)&sl->reg_num, count);100 return count;101}102static DEVICE_ATTR_RO(id);103 104static struct attribute *w1_slave_attrs[] = {105 &dev_attr_name.attr,106 &dev_attr_id.attr,107 NULL,108};109ATTRIBUTE_GROUPS(w1_slave);110 111/* Default family */112 113static ssize_t rw_write(struct file *filp, struct kobject *kobj,114 struct bin_attribute *bin_attr, char *buf, loff_t off,115 size_t count)116{117 struct w1_slave *sl = kobj_to_w1_slave(kobj);118 119 mutex_lock(&sl->master->mutex);120 if (w1_reset_select_slave(sl)) {121 count = 0;122 goto out_up;123 }124 125 w1_write_block(sl->master, buf, count);126 127out_up:128 mutex_unlock(&sl->master->mutex);129 return count;130}131 132static ssize_t rw_read(struct file *filp, struct kobject *kobj,133 struct bin_attribute *bin_attr, char *buf, loff_t off,134 size_t count)135{136 struct w1_slave *sl = kobj_to_w1_slave(kobj);137 138 mutex_lock(&sl->master->mutex);139 w1_read_block(sl->master, buf, count);140 mutex_unlock(&sl->master->mutex);141 return count;142}143 144static BIN_ATTR_RW(rw, PAGE_SIZE);145 146static struct bin_attribute *w1_slave_bin_attrs[] = {147 &bin_attr_rw,148 NULL,149};150 151static const struct attribute_group w1_slave_default_group = {152 .bin_attrs = w1_slave_bin_attrs,153};154 155static const struct attribute_group *w1_slave_default_groups[] = {156 &w1_slave_default_group,157 NULL,158};159 160static const struct w1_family_ops w1_default_fops = {161 .groups = w1_slave_default_groups,162};163 164static struct w1_family w1_default_family = {165 .fops = &w1_default_fops,166};167 168static int w1_uevent(const struct device *dev, struct kobj_uevent_env *env);169 170static const struct bus_type w1_bus_type = {171 .name = "w1",172 .uevent = w1_uevent,173};174 175struct device_driver w1_master_driver = {176 .name = "w1_master_driver",177 .bus = &w1_bus_type,178 .probe = w1_master_probe,179};180 181struct device w1_master_device = {182 .parent = NULL,183 .bus = &w1_bus_type,184 .init_name = "w1 bus master",185 .driver = &w1_master_driver,186 .release = &w1_master_release187};188 189static struct device_driver w1_slave_driver = {190 .name = "w1_slave_driver",191 .bus = &w1_bus_type,192};193 194#if 0195struct device w1_slave_device = {196 .parent = NULL,197 .bus = &w1_bus_type,198 .init_name = "w1 bus slave",199 .driver = &w1_slave_driver,200 .release = &w1_slave_release201};202#endif /* 0 */203 204static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)205{206 struct w1_master *md = dev_to_w1_master(dev);207 ssize_t count;208 209 mutex_lock(&md->mutex);210 count = sprintf(buf, "%s\n", md->name);211 mutex_unlock(&md->mutex);212 213 return count;214}215 216static ssize_t w1_master_attribute_store_search(struct device * dev,217 struct device_attribute *attr,218 const char * buf, size_t count)219{220 long tmp;221 struct w1_master *md = dev_to_w1_master(dev);222 int ret;223 224 ret = kstrtol(buf, 0, &tmp);225 if (ret)226 return ret;227 228 mutex_lock(&md->mutex);229 md->search_count = tmp;230 mutex_unlock(&md->mutex);231 /* Only wake if it is going to be searching. */232 if (tmp)233 wake_up_process(md->thread);234 235 return count;236}237 238static ssize_t w1_master_attribute_show_search(struct device *dev,239 struct device_attribute *attr,240 char *buf)241{242 struct w1_master *md = dev_to_w1_master(dev);243 ssize_t count;244 245 mutex_lock(&md->mutex);246 count = sprintf(buf, "%d\n", md->search_count);247 mutex_unlock(&md->mutex);248 249 return count;250}251 252static ssize_t w1_master_attribute_store_pullup(struct device *dev,253 struct device_attribute *attr,254 const char *buf, size_t count)255{256 long tmp;257 struct w1_master *md = dev_to_w1_master(dev);258 int ret;259 260 ret = kstrtol(buf, 0, &tmp);261 if (ret)262 return ret;263 264 mutex_lock(&md->mutex);265 md->enable_pullup = tmp;266 mutex_unlock(&md->mutex);267 268 return count;269}270 271static ssize_t w1_master_attribute_show_pullup(struct device *dev,272 struct device_attribute *attr,273 char *buf)274{275 struct w1_master *md = dev_to_w1_master(dev);276 ssize_t count;277 278 mutex_lock(&md->mutex);279 count = sprintf(buf, "%d\n", md->enable_pullup);280 mutex_unlock(&md->mutex);281 282 return count;283}284 285static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)286{287 struct w1_master *md = dev_to_w1_master(dev);288 ssize_t count;289 290 mutex_lock(&md->mutex);291 count = sprintf(buf, "0x%p\n", md->bus_master);292 mutex_unlock(&md->mutex);293 return count;294}295 296static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)297{298 return sprintf(buf, "%d\n", w1_timeout);299}300 301static ssize_t w1_master_attribute_show_timeout_us(struct device *dev,302 struct device_attribute *attr, char *buf)303{304 return sprintf(buf, "%d\n", w1_timeout_us);305}306 307static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,308 struct device_attribute *attr, const char *buf, size_t count)309{310 int tmp;311 struct w1_master *md = dev_to_w1_master(dev);312 313 if (kstrtoint(buf, 0, &tmp) || tmp < 1)314 return -EINVAL;315 316 mutex_lock(&md->mutex);317 md->max_slave_count = tmp;318 /* allow each time the max_slave_count is updated */319 clear_bit(W1_WARN_MAX_COUNT, &md->flags);320 mutex_unlock(&md->mutex);321 322 return count;323}324 325static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)326{327 struct w1_master *md = dev_to_w1_master(dev);328 ssize_t count;329 330 mutex_lock(&md->mutex);331 count = sprintf(buf, "%d\n", md->max_slave_count);332 mutex_unlock(&md->mutex);333 return count;334}335 336static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)337{338 struct w1_master *md = dev_to_w1_master(dev);339 ssize_t count;340 341 mutex_lock(&md->mutex);342 count = sprintf(buf, "%lu\n", md->attempts);343 mutex_unlock(&md->mutex);344 return count;345}346 347static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)348{349 struct w1_master *md = dev_to_w1_master(dev);350 ssize_t count;351 352 mutex_lock(&md->mutex);353 count = sprintf(buf, "%d\n", md->slave_count);354 mutex_unlock(&md->mutex);355 return count;356}357 358static ssize_t w1_master_attribute_show_slaves(struct device *dev,359 struct device_attribute *attr, char *buf)360{361 struct w1_master *md = dev_to_w1_master(dev);362 int c = PAGE_SIZE;363 struct list_head *ent, *n;364 struct w1_slave *sl = NULL;365 366 mutex_lock(&md->list_mutex);367 368 list_for_each_safe(ent, n, &md->slist) {369 sl = list_entry(ent, struct w1_slave, w1_slave_entry);370 371 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);372 }373 if (!sl)374 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");375 376 mutex_unlock(&md->list_mutex);377 378 return PAGE_SIZE - c;379}380 381static ssize_t w1_master_attribute_show_add(struct device *dev,382 struct device_attribute *attr, char *buf)383{384 int c = PAGE_SIZE;385 c -= snprintf(buf+PAGE_SIZE - c, c,386 "write device id xx-xxxxxxxxxxxx to add slave\n");387 return PAGE_SIZE - c;388}389 390static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,391 struct w1_reg_num *rn)392{393 unsigned int family;394 unsigned long long id;395 int i;396 u64 rn64_le;397 398 /* The CRC value isn't read from the user because the sysfs directory399 * doesn't include it and most messages from the bus search don't400 * print it either. It would be unreasonable for the user to then401 * provide it.402 */403 const char *error_msg = "bad slave string format, expecting "404 "ff-dddddddddddd\n";405 406 if (buf[2] != '-') {407 dev_err(dev, "%s", error_msg);408 return -EINVAL;409 }410 i = sscanf(buf, "%02x-%012llx", &family, &id);411 if (i != 2) {412 dev_err(dev, "%s", error_msg);413 return -EINVAL;414 }415 rn->family = family;416 rn->id = id;417 418 rn64_le = cpu_to_le64(*(u64 *)rn);419 rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);420 421#if 0422 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",423 rn->family, (unsigned long long)rn->id, rn->crc);424#endif425 426 return 0;427}428 429/* Searches the slaves in the w1_master and returns a pointer or NULL.430 * Note: must not hold list_mutex431 */432struct w1_slave *w1_slave_search_device(struct w1_master *dev,433 struct w1_reg_num *rn)434{435 struct w1_slave *sl;436 mutex_lock(&dev->list_mutex);437 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {438 if (sl->reg_num.family == rn->family &&439 sl->reg_num.id == rn->id &&440 sl->reg_num.crc == rn->crc) {441 mutex_unlock(&dev->list_mutex);442 return sl;443 }444 }445 mutex_unlock(&dev->list_mutex);446 return NULL;447}448 449static ssize_t w1_master_attribute_store_add(struct device *dev,450 struct device_attribute *attr,451 const char *buf, size_t count)452{453 struct w1_master *md = dev_to_w1_master(dev);454 struct w1_reg_num rn;455 struct w1_slave *sl;456 ssize_t result = count;457 458 if (w1_atoreg_num(dev, buf, count, &rn))459 return -EINVAL;460 461 mutex_lock(&md->mutex);462 sl = w1_slave_search_device(md, &rn);463 /* It would be nice to do a targeted search one the one-wire bus464 * for the new device to see if it is out there or not. But the465 * current search doesn't support that.466 */467 if (sl) {468 dev_info(dev, "Device %s already exists\n", sl->name);469 result = -EINVAL;470 } else {471 w1_attach_slave_device(md, &rn);472 }473 mutex_unlock(&md->mutex);474 475 return result;476}477 478static ssize_t w1_master_attribute_show_remove(struct device *dev,479 struct device_attribute *attr, char *buf)480{481 int c = PAGE_SIZE;482 c -= snprintf(buf+PAGE_SIZE - c, c,483 "write device id xx-xxxxxxxxxxxx to remove slave\n");484 return PAGE_SIZE - c;485}486 487static ssize_t w1_master_attribute_store_remove(struct device *dev,488 struct device_attribute *attr,489 const char *buf, size_t count)490{491 struct w1_master *md = dev_to_w1_master(dev);492 struct w1_reg_num rn;493 struct w1_slave *sl;494 ssize_t result;495 496 if (w1_atoreg_num(dev, buf, count, &rn))497 return -EINVAL;498 499 mutex_lock(&md->mutex);500 sl = w1_slave_search_device(md, &rn);501 if (sl) {502 result = w1_slave_detach(sl);503 /* refcnt 0 means it was detached in the call */504 if (result == 0)505 result = count;506 } else {507 dev_info(dev, "Device %02x-%012llx doesn't exist\n", rn.family,508 (unsigned long long)rn.id);509 result = -EINVAL;510 }511 mutex_unlock(&md->mutex);512 513 return result;514}515 516#define W1_MASTER_ATTR_RO(_name, _mode) \517 struct device_attribute w1_master_attribute_##_name = \518 __ATTR(w1_master_##_name, _mode, \519 w1_master_attribute_show_##_name, NULL)520 521#define W1_MASTER_ATTR_RW(_name, _mode) \522 struct device_attribute w1_master_attribute_##_name = \523 __ATTR(w1_master_##_name, _mode, \524 w1_master_attribute_show_##_name, \525 w1_master_attribute_store_##_name)526 527static W1_MASTER_ATTR_RO(name, S_IRUGO);528static W1_MASTER_ATTR_RO(slaves, S_IRUGO);529static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);530static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);531static W1_MASTER_ATTR_RO(attempts, S_IRUGO);532static W1_MASTER_ATTR_RO(timeout, S_IRUGO);533static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO);534static W1_MASTER_ATTR_RO(pointer, S_IRUGO);535static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);536static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);537static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);538static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);539 540static struct attribute *w1_master_default_attrs[] = {541 &w1_master_attribute_name.attr,542 &w1_master_attribute_slaves.attr,543 &w1_master_attribute_slave_count.attr,544 &w1_master_attribute_max_slave_count.attr,545 &w1_master_attribute_attempts.attr,546 &w1_master_attribute_timeout.attr,547 &w1_master_attribute_timeout_us.attr,548 &w1_master_attribute_pointer.attr,549 &w1_master_attribute_search.attr,550 &w1_master_attribute_pullup.attr,551 &w1_master_attribute_add.attr,552 &w1_master_attribute_remove.attr,553 NULL554};555 556static const struct attribute_group w1_master_defattr_group = {557 .attrs = w1_master_default_attrs,558};559 560int w1_create_master_attributes(struct w1_master *master)561{562 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);563}564 565void w1_destroy_master_attributes(struct w1_master *master)566{567 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);568}569 570static int w1_uevent(const struct device *dev, struct kobj_uevent_env *env)571{572 const struct w1_master *md = NULL;573 const struct w1_slave *sl = NULL;574 const char *event_owner, *name;575 int err = 0;576 577 if (dev->driver == &w1_master_driver) {578 md = container_of(dev, struct w1_master, dev);579 event_owner = "master";580 name = md->name;581 } else if (dev->driver == &w1_slave_driver) {582 sl = container_of(dev, struct w1_slave, dev);583 event_owner = "slave";584 name = sl->name;585 } else {586 dev_dbg(dev, "Unknown event.\n");587 return -EINVAL;588 }589 590 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",591 event_owner, name, dev_name(dev));592 593 if (dev->driver != &w1_slave_driver || !sl)594 goto end;595 596 err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);597 if (err)598 goto end;599 600 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",601 (unsigned long long)sl->reg_num.id);602end:603 return err;604}605 606static int w1_family_notify(unsigned long action, struct w1_slave *sl)607{608 const struct w1_family_ops *fops;609 int err;610 611 fops = sl->family->fops;612 613 if (!fops)614 return 0;615 616 switch (action) {617 case BUS_NOTIFY_ADD_DEVICE:618 /* if the family driver needs to initialize something... */619 if (fops->add_slave) {620 err = fops->add_slave(sl);621 if (err < 0) {622 dev_err(&sl->dev,623 "add_slave() call failed. err=%d\n",624 err);625 return err;626 }627 }628 if (fops->groups) {629 err = sysfs_create_groups(&sl->dev.kobj, fops->groups);630 if (err) {631 dev_err(&sl->dev,632 "sysfs group creation failed. err=%d\n",633 err);634 return err;635 }636 }637 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info) {638 struct device *hwmon639 = hwmon_device_register_with_info(&sl->dev,640 "w1_slave_temp", sl,641 fops->chip_info,642 NULL);643 if (IS_ERR(hwmon)) {644 dev_warn(&sl->dev,645 "could not create hwmon device\n");646 } else {647 sl->hwmon = hwmon;648 }649 }650 break;651 case BUS_NOTIFY_DEL_DEVICE:652 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info &&653 sl->hwmon)654 hwmon_device_unregister(sl->hwmon);655 if (fops->remove_slave)656 sl->family->fops->remove_slave(sl);657 if (fops->groups)658 sysfs_remove_groups(&sl->dev.kobj, fops->groups);659 break;660 }661 return 0;662}663 664static int __w1_attach_slave_device(struct w1_slave *sl)665{666 int err;667 668 sl->dev.parent = &sl->master->dev;669 sl->dev.driver = &w1_slave_driver;670 sl->dev.bus = &w1_bus_type;671 sl->dev.release = &w1_slave_release;672 sl->dev.groups = w1_slave_groups;673 sl->dev.of_node = of_find_matching_node(sl->master->dev.of_node,674 sl->family->of_match_table);675 676 dev_set_name(&sl->dev, "%02x-%012llx",677 (unsigned int) sl->reg_num.family,678 (unsigned long long) sl->reg_num.id);679 snprintf(&sl->name[0], sizeof(sl->name),680 "%02x-%012llx",681 (unsigned int) sl->reg_num.family,682 (unsigned long long) sl->reg_num.id);683 684 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,685 dev_name(&sl->dev), sl);686 687 /* suppress for w1_family_notify before sending KOBJ_ADD */688 dev_set_uevent_suppress(&sl->dev, true);689 690 err = device_register(&sl->dev);691 if (err < 0) {692 dev_err(&sl->dev,693 "Device registration [%s] failed. err=%d\n",694 dev_name(&sl->dev), err);695 of_node_put(sl->dev.of_node);696 put_device(&sl->dev);697 return err;698 }699 w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl);700 701 dev_set_uevent_suppress(&sl->dev, false);702 kobject_uevent(&sl->dev.kobj, KOBJ_ADD);703 704 mutex_lock(&sl->master->list_mutex);705 list_add_tail(&sl->w1_slave_entry, &sl->master->slist);706 mutex_unlock(&sl->master->list_mutex);707 708 return 0;709}710 711int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)712{713 struct w1_slave *sl;714 struct w1_family *f;715 int err;716 struct w1_netlink_msg msg;717 718 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);719 if (!sl) {720 dev_err(&dev->dev,721 "%s: failed to allocate new slave device.\n",722 __func__);723 return -ENOMEM;724 }725 726 727 sl->owner = THIS_MODULE;728 sl->master = dev;729 set_bit(W1_SLAVE_ACTIVE, &sl->flags);730 731 memset(&msg, 0, sizeof(msg));732 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));733 atomic_set(&sl->refcnt, 1);734 atomic_inc(&sl->master->refcnt);735 dev->slave_count++;736 dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",737 rn->family, (unsigned long long)rn->id, rn->crc);738 739 /* slave modules need to be loaded in a context with unlocked mutex */740 mutex_unlock(&dev->mutex);741 request_module("w1-family-0x%02X", rn->family);742 mutex_lock(&dev->mutex);743 744 spin_lock(&w1_flock);745 f = w1_family_registered(rn->family);746 if (!f) {747 f= &w1_default_family;748 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",749 rn->family, rn->family,750 (unsigned long long)rn->id, rn->crc);751 }752 __w1_family_get(f);753 spin_unlock(&w1_flock);754 755 sl->family = f;756 757 err = __w1_attach_slave_device(sl);758 if (err < 0) {759 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,760 sl->name);761 dev->slave_count--;762 w1_family_put(sl->family);763 atomic_dec(&sl->master->refcnt);764 kfree(sl);765 return err;766 }767 768 sl->ttl = dev->slave_ttl;769 770 memcpy(msg.id.id, rn, sizeof(msg.id));771 msg.type = W1_SLAVE_ADD;772 w1_netlink_send(dev, &msg);773 774 return 0;775}776 777int w1_unref_slave(struct w1_slave *sl)778{779 struct w1_master *dev = sl->master;780 int refcnt;781 mutex_lock(&dev->list_mutex);782 refcnt = atomic_sub_return(1, &sl->refcnt);783 if (refcnt == 0) {784 struct w1_netlink_msg msg;785 786 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,787 sl->name, sl);788 789 list_del(&sl->w1_slave_entry);790 791 memset(&msg, 0, sizeof(msg));792 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));793 msg.type = W1_SLAVE_REMOVE;794 w1_netlink_send(sl->master, &msg);795 796 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);797 device_unregister(&sl->dev);798 #ifdef DEBUG799 memset(sl, 0, sizeof(*sl));800 #endif801 kfree(sl);802 }803 atomic_dec(&dev->refcnt);804 mutex_unlock(&dev->list_mutex);805 return refcnt;806}807 808int w1_slave_detach(struct w1_slave *sl)809{810 /* Only detach a slave once as it decreases the refcnt each time. */811 int destroy_now;812 mutex_lock(&sl->master->list_mutex);813 destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);814 set_bit(W1_SLAVE_DETACH, &sl->flags);815 mutex_unlock(&sl->master->list_mutex);816 817 if (destroy_now)818 destroy_now = !w1_unref_slave(sl);819 return destroy_now ? 0 : -EBUSY;820}821 822struct w1_master *w1_search_master_id(u32 id)823{824 struct w1_master *dev = NULL, *iter;825 826 mutex_lock(&w1_mlock);827 list_for_each_entry(iter, &w1_masters, w1_master_entry) {828 if (iter->id == id) {829 dev = iter;830 atomic_inc(&iter->refcnt);831 break;832 }833 }834 mutex_unlock(&w1_mlock);835 836 return dev;837}838 839struct w1_slave *w1_search_slave(struct w1_reg_num *id)840{841 struct w1_master *dev;842 struct w1_slave *sl = NULL, *iter;843 844 mutex_lock(&w1_mlock);845 list_for_each_entry(dev, &w1_masters, w1_master_entry) {846 mutex_lock(&dev->list_mutex);847 list_for_each_entry(iter, &dev->slist, w1_slave_entry) {848 if (iter->reg_num.family == id->family &&849 iter->reg_num.id == id->id &&850 iter->reg_num.crc == id->crc) {851 sl = iter;852 atomic_inc(&dev->refcnt);853 atomic_inc(&iter->refcnt);854 break;855 }856 }857 mutex_unlock(&dev->list_mutex);858 859 if (sl)860 break;861 }862 mutex_unlock(&w1_mlock);863 864 return sl;865}866 867void w1_reconnect_slaves(struct w1_family *f, int attach)868{869 struct w1_slave *sl, *sln;870 struct w1_master *dev;871 872 mutex_lock(&w1_mlock);873 list_for_each_entry(dev, &w1_masters, w1_master_entry) {874 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "875 "for family %02x.\n", dev->name, f->fid);876 mutex_lock(&dev->mutex);877 mutex_lock(&dev->list_mutex);878 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {879 /* If it is a new family, slaves with the default880 * family driver and are that family will be881 * connected. If the family is going away, devices882 * matching that family are reconneced.883 */884 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT885 && sl->reg_num.family == f->fid) ||886 (!attach && sl->family->fid == f->fid)) {887 struct w1_reg_num rn;888 889 mutex_unlock(&dev->list_mutex);890 memcpy(&rn, &sl->reg_num, sizeof(rn));891 /* If it was already in use let the automatic892 * scan pick it up again later.893 */894 if (!w1_slave_detach(sl))895 w1_attach_slave_device(dev, &rn);896 mutex_lock(&dev->list_mutex);897 }898 }899 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "900 "has been finished.\n", dev->name);901 mutex_unlock(&dev->list_mutex);902 mutex_unlock(&dev->mutex);903 }904 mutex_unlock(&w1_mlock);905}906 907static int w1_addr_crc_is_valid(struct w1_master *dev, u64 rn)908{909 u64 rn_le = cpu_to_le64(rn);910 struct w1_reg_num *tmp = (struct w1_reg_num *)&rn;911 u8 crc;912 913 crc = w1_calc_crc8((u8 *)&rn_le, 7);914 915 /* quirk:916 * DS28E04 (1w eeprom) has strapping pins to change917 * address, but will not update the crc. So normal rules918 * for consistent w1 addresses are violated. We test919 * with the 7 LSBs of the address forced high.920 *921 * (char*)&rn_le = { family, addr_lsb, ..., addr_msb, crc }.922 */923 if (crc != tmp->crc && tmp->family == W1_FAMILY_DS28E04) {924 u64 corr_le = rn_le;925 926 ((u8 *)&corr_le)[1] |= 0x7f;927 crc = w1_calc_crc8((u8 *)&corr_le, 7);928 929 dev_info(&dev->dev, "DS28E04 crc workaround on %02x.%012llx.%02x\n",930 tmp->family, (unsigned long long)tmp->id, tmp->crc);931 }932 933 if (crc != tmp->crc) {934 dev_dbg(&dev->dev, "w1 addr crc mismatch: %02x.%012llx.%02x != 0x%02x.\n",935 tmp->family, (unsigned long long)tmp->id, tmp->crc, crc);936 return 0;937 }938 return 1;939}940 941void w1_slave_found(struct w1_master *dev, u64 rn)942{943 struct w1_slave *sl;944 struct w1_reg_num *tmp;945 946 atomic_inc(&dev->refcnt);947 948 tmp = (struct w1_reg_num *) &rn;949 950 sl = w1_slave_search_device(dev, tmp);951 if (sl) {952 set_bit(W1_SLAVE_ACTIVE, &sl->flags);953 } else {954 if (rn && w1_addr_crc_is_valid(dev, rn))955 w1_attach_slave_device(dev, tmp);956 }957 958 atomic_dec(&dev->refcnt);959}960 961/**962 * w1_search() - Performs a ROM Search & registers any devices found.963 * @dev: The master device to search964 * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH965 * to return only devices in the alarmed state966 * @cb: Function to call when a device is found967 *968 * The 1-wire search is a simple binary tree search.969 * For each bit of the address, we read two bits and write one bit.970 * The bit written will put to sleep all devies that don't match that bit.971 * When the two reads differ, the direction choice is obvious.972 * When both bits are 0, we must choose a path to take.973 * When we can scan all 64 bits without having to choose a path, we are done.974 *975 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com976 *977 */978void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)979{980 u64 last_rn, rn, tmp64;981 int i, slave_count = 0;982 int last_zero, last_device;983 int search_bit, desc_bit;984 u8 triplet_ret = 0;985 986 search_bit = 0;987 rn = dev->search_id;988 last_rn = 0;989 last_device = 0;990 last_zero = -1;991 992 desc_bit = 64;993 994 while ( !last_device && (slave_count++ < dev->max_slave_count) ) {995 last_rn = rn;996 rn = 0;997 998 /*999 * Reset bus and all 1-wire device state machines1000 * so they can respond to our requests.1001 *1002 * Return 0 - device(s) present, 1 - no devices present.1003 */1004 mutex_lock(&dev->bus_mutex);1005 if (w1_reset_bus(dev)) {1006 mutex_unlock(&dev->bus_mutex);1007 dev_dbg(&dev->dev, "No devices present on the wire.\n");1008 break;1009 }1010 1011 /* Do fast search on single slave bus */1012 if (dev->max_slave_count == 1) {1013 int rv;1014 w1_write_8(dev, W1_READ_ROM);1015 rv = w1_read_block(dev, (u8 *)&rn, 8);1016 mutex_unlock(&dev->bus_mutex);1017 1018 if (rv == 8 && rn)1019 cb(dev, rn);1020 1021 break;1022 }1023 1024 /* Start the search */1025 w1_write_8(dev, search_type);1026 for (i = 0; i < 64; ++i) {1027 /* Determine the direction/search bit */1028 if (i == desc_bit)1029 search_bit = 1; /* took the 0 path last time, so take the 1 path */1030 else if (i > desc_bit)1031 search_bit = 0; /* take the 0 path on the next branch */1032 else1033 search_bit = ((last_rn >> i) & 0x1);1034 1035 /* Read two bits and write one bit */1036 triplet_ret = w1_triplet(dev, search_bit);1037 1038 /* quit if no device responded */1039 if ( (triplet_ret & 0x03) == 0x03 )1040 break;1041 1042 /* If both directions were valid, and we took the 0 path... */1043 if (triplet_ret == 0)1044 last_zero = i;1045 1046 /* extract the direction taken & update the device number */1047 tmp64 = (triplet_ret >> 2);1048 rn |= (tmp64 << i);1049 1050 if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {1051 mutex_unlock(&dev->bus_mutex);1052 dev_dbg(&dev->dev, "Abort w1_search\n");1053 return;1054 }1055 }1056 mutex_unlock(&dev->bus_mutex);1057 1058 if ( (triplet_ret & 0x03) != 0x03 ) {1059 if ((desc_bit == last_zero) || (last_zero < 0)) {1060 last_device = 1;1061 dev->search_id = 0;1062 } else {1063 dev->search_id = rn;1064 }1065 desc_bit = last_zero;1066 cb(dev, rn);1067 }1068 1069 if (!last_device && slave_count == dev->max_slave_count &&1070 !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {1071 /* Only max_slave_count will be scanned in a search,1072 * but it will start where it left off next search1073 * until all ids are identified and then it will start1074 * over. A continued search will report the previous1075 * last id as the first id (provided it is still on the1076 * bus).1077 */1078 dev_info(&dev->dev, "%s: max_slave_count %d reached, "1079 "will continue next search.\n", __func__,1080 dev->max_slave_count);1081 set_bit(W1_WARN_MAX_COUNT, &dev->flags);1082 }1083 }1084}1085 1086void w1_search_process_cb(struct w1_master *dev, u8 search_type,1087 w1_slave_found_callback cb)1088{1089 struct w1_slave *sl, *sln;1090 1091 mutex_lock(&dev->list_mutex);1092 list_for_each_entry(sl, &dev->slist, w1_slave_entry)1093 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);1094 mutex_unlock(&dev->list_mutex);1095 1096 w1_search_devices(dev, search_type, cb);1097 1098 mutex_lock(&dev->list_mutex);1099 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {1100 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {1101 mutex_unlock(&dev->list_mutex);1102 w1_slave_detach(sl);1103 mutex_lock(&dev->list_mutex);1104 }1105 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))1106 sl->ttl = dev->slave_ttl;1107 }1108 mutex_unlock(&dev->list_mutex);1109 1110 if (dev->search_count > 0)1111 dev->search_count--;1112}1113 1114static void w1_search_process(struct w1_master *dev, u8 search_type)1115{1116 w1_search_process_cb(dev, search_type, w1_slave_found);1117}1118 1119/**1120 * w1_process_callbacks() - execute each dev->async_list callback entry1121 * @dev: w1_master device1122 *1123 * The w1 master list_mutex must be held.1124 *1125 * Return: 1 if there were commands to executed 0 otherwise1126 */1127int w1_process_callbacks(struct w1_master *dev)1128{1129 int ret = 0;1130 struct w1_async_cmd *async_cmd, *async_n;1131 1132 /* The list can be added to in another thread, loop until it is empty */1133 while (!list_empty(&dev->async_list)) {1134 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,1135 async_entry) {1136 /* drop the lock, if it is a search it can take a long1137 * time */1138 mutex_unlock(&dev->list_mutex);1139 async_cmd->cb(dev, async_cmd);1140 ret = 1;1141 mutex_lock(&dev->list_mutex);1142 }1143 }1144 return ret;1145}1146 1147int w1_process(void *data)1148{1149 struct w1_master *dev = (struct w1_master *) data;1150 /* As long as w1_timeout is only set by a module parameter the sleep1151 * time can be calculated in jiffies once.1152 */1153 const unsigned long jtime =1154 usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);1155 /* remainder if it woke up early */1156 unsigned long jremain = 0;1157 1158 atomic_inc(&dev->refcnt);1159 1160 for (;;) {1161 1162 if (!jremain && dev->search_count) {1163 mutex_lock(&dev->mutex);1164 w1_search_process(dev, W1_SEARCH);1165 mutex_unlock(&dev->mutex);1166 }1167 1168 mutex_lock(&dev->list_mutex);1169 /* Note, w1_process_callback drops the lock while processing,1170 * but locks it again before returning.1171 */1172 if (!w1_process_callbacks(dev) && jremain) {1173 /* a wake up is either to stop the thread, process1174 * callbacks, or search, it isn't process callbacks, so1175 * schedule a search.1176 */1177 jremain = 1;1178 }1179 1180 __set_current_state(TASK_INTERRUPTIBLE);1181 1182 /* hold list_mutex until after interruptible to prevent loosing1183 * the wakeup signal when async_cmd is added.1184 */1185 mutex_unlock(&dev->list_mutex);1186 1187 if (kthread_should_stop()) {1188 __set_current_state(TASK_RUNNING);1189 break;1190 }1191 1192 /* Only sleep when the search is active. */1193 if (dev->search_count) {1194 if (!jremain)1195 jremain = jtime;1196 jremain = schedule_timeout(jremain);1197 }1198 else1199 schedule();1200 }1201 1202 atomic_dec(&dev->refcnt);1203 1204 return 0;1205}1206 1207static int __init w1_init(void)1208{1209 int retval;1210 1211 pr_info("Driver for 1-wire Dallas network protocol.\n");1212 1213 w1_init_netlink();1214 1215 retval = bus_register(&w1_bus_type);1216 if (retval) {1217 pr_err("Failed to register bus. err=%d.\n", retval);1218 goto err_out_exit_init;1219 }1220 1221 retval = driver_register(&w1_master_driver);1222 if (retval) {1223 pr_err("Failed to register master driver. err=%d.\n",1224 retval);1225 goto err_out_bus_unregister;1226 }1227 1228 retval = driver_register(&w1_slave_driver);1229 if (retval) {1230 pr_err("Failed to register slave driver. err=%d.\n",1231 retval);1232 goto err_out_master_unregister;1233 }1234 1235 return 0;1236 1237#if 01238/* For undoing the slave register if there was a step after it. */1239err_out_slave_unregister:1240 driver_unregister(&w1_slave_driver);1241#endif1242 1243err_out_master_unregister:1244 driver_unregister(&w1_master_driver);1245 1246err_out_bus_unregister:1247 bus_unregister(&w1_bus_type);1248 1249err_out_exit_init:1250 return retval;1251}1252 1253static void __exit w1_fini(void)1254{1255 struct w1_master *dev, *n;1256 1257 /* Set netlink removal messages and some cleanup */1258 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry)1259 __w1_remove_master_device(dev);1260 1261 w1_fini_netlink();1262 1263 driver_unregister(&w1_slave_driver);1264 driver_unregister(&w1_master_driver);1265 bus_unregister(&w1_bus_type);1266}1267 1268module_init(w1_init);1269module_exit(w1_fini);1270 1271MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");1272MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");1273MODULE_LICENSE("GPL");1274