/* * w1.c * * Copyright (c) 2004 Evgeniy Polyakov * * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "w1.h" #include "w1_log.h" #include "w1_int.h" #include "w1_family.h" #include "w1_netlink.h" MODULE_LICENSE("GPL"); MODULE_AUTHOR("Evgeniy Polyakov "); MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); static int w1_timeout = 10; int w1_max_slave_count = 64; int w1_max_slave_ttl = 10; module_param_named(timeout, w1_timeout, int, 0); MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches"); /* A search stops when w1_max_slave_count devices have been found in that * search. The next search will start over and detect the same set of devices * on a static 1-wire bus. Memory is not allocated based on this number, just * on the number of devices known to the kernel. Having a high number does not * consume additional resources. As a special case, if there is only one * device on the network and w1_max_slave_count is set to 1, the device id can * be read directly skipping the normal slower search process. */ module_param_named(max_slave_count, w1_max_slave_count, int, 0); MODULE_PARM_DESC(max_slave_count, "maximum number of slaves detected in a search"); module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); MODULE_PARM_DESC(slave_ttl, "Number of searches not seeing a slave before it will be removed"); DEFINE_MUTEX(w1_mlock); LIST_HEAD(w1_masters); static int w1_master_match(struct device *dev, struct device_driver *drv) { return 1; } static int w1_master_probe(struct device *dev) { return -ENODEV; } static void w1_master_release(struct device *dev) { struct w1_master *md = dev_to_w1_master(dev); dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); kfree(md); } static void w1_slave_release(struct device *dev) { struct w1_slave *sl = dev_to_w1_slave(dev); dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl); w1_family_put(sl->family); sl->master->slave_count--; } static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_slave *sl = dev_to_w1_slave(dev); return sprintf(buf, "%s\n", sl->name); } static DEVICE_ATTR_RO(name); static ssize_t id_show(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_slave *sl = dev_to_w1_slave(dev); ssize_t count = sizeof(sl->reg_num); memcpy(buf, (u8 *)&sl->reg_num, count); return count; } static DEVICE_ATTR_RO(id); static struct attribute *w1_slave_attrs[] = { &dev_attr_name.attr, &dev_attr_id.attr, NULL, }; ATTRIBUTE_GROUPS(w1_slave); /* Default family */ static ssize_t rw_write(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); mutex_lock(&sl->master->mutex); if (w1_reset_select_slave(sl)) { count = 0; goto out_up; } w1_write_block(sl->master, buf, count); out_up: mutex_unlock(&sl->master->mutex); return count; } static ssize_t rw_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); mutex_lock(&sl->master->mutex); w1_read_block(sl->master, buf, count); mutex_unlock(&sl->master->mutex); return count; } static BIN_ATTR_RW(rw, PAGE_SIZE); static struct bin_attribute *w1_slave_bin_attrs[] = { &bin_attr_rw, NULL, }; static const struct attribute_group w1_slave_default_group = { .bin_attrs = w1_slave_bin_attrs, }; static const struct attribute_group *w1_slave_default_groups[] = { &w1_slave_default_group, NULL, }; static struct w1_family_ops w1_default_fops = { .groups = w1_slave_default_groups, }; static struct w1_family w1_default_family = { .fops = &w1_default_fops, }; static int w1_uevent(struct device *dev, struct kobj_uevent_env *env); static struct bus_type w1_bus_type = { .name = "w1", .match = w1_master_match, .uevent = w1_uevent, }; struct device_driver w1_master_driver = { .name = "w1_master_driver", .bus = &w1_bus_type, .probe = w1_master_probe, }; struct device w1_master_device = { .parent = NULL, .bus = &w1_bus_type, .init_name = "w1 bus master", .driver = &w1_master_driver, .release = &w1_master_release }; static struct device_driver w1_slave_driver = { .name = "w1_slave_driver", .bus = &w1_bus_type, }; #if 0 struct device w1_slave_device = { .parent = NULL, .bus = &w1_bus_type, .init_name = "w1 bus slave", .driver = &w1_slave_driver, .release = &w1_slave_release }; #endif /* 0 */ static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); ssize_t count; mutex_lock(&md->mutex); count = sprintf(buf, "%s\n", md->name); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_store_search(struct device * dev, struct device_attribute *attr, const char * buf, size_t count) { long tmp; struct w1_master *md = dev_to_w1_master(dev); int ret; ret = kstrtol(buf, 0, &tmp); if (ret) return ret; mutex_lock(&md->mutex); md->search_count = tmp; mutex_unlock(&md->mutex); /* Only wake if it is going to be searching. */ if (tmp) wake_up_process(md->thread); return count; } static ssize_t w1_master_attribute_show_search(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); ssize_t count; mutex_lock(&md->mutex); count = sprintf(buf, "%d\n", md->search_count); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_store_pullup(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { long tmp; struct w1_master *md = dev_to_w1_master(dev); int ret; ret = kstrtol(buf, 0, &tmp); if (ret) return ret; mutex_lock(&md->mutex); md->enable_pullup = tmp; mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_show_pullup(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); ssize_t count; mutex_lock(&md->mutex); count = sprintf(buf, "%d\n", md->enable_pullup); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); ssize_t count; mutex_lock(&md->mutex); count = sprintf(buf, "0x%p\n", md->bus_master); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) { ssize_t count; count = sprintf(buf, "%d\n", w1_timeout); return count; } static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int tmp; struct w1_master *md = dev_to_w1_master(dev); if (kstrtoint(buf, 0, &tmp) == -EINVAL || tmp < 1) return -EINVAL; mutex_lock(&md->mutex); md->max_slave_count = tmp; /* allow each time the max_slave_count is updated */ clear_bit(W1_WARN_MAX_COUNT, &md->flags); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); ssize_t count; mutex_lock(&md->mutex); count = sprintf(buf, "%d\n", md->max_slave_count); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); ssize_t count; mutex_lock(&md->mutex); count = sprintf(buf, "%lu\n", md->attempts); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); ssize_t count; mutex_lock(&md->mutex); count = sprintf(buf, "%d\n", md->slave_count); mutex_unlock(&md->mutex); return count; } static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = dev_to_w1_master(dev); int c = PAGE_SIZE; struct list_head *ent, *n; struct w1_slave *sl = NULL; mutex_lock(&md->list_mutex); list_for_each_safe(ent, n, &md->slist) { sl = list_entry(ent, struct w1_slave, w1_slave_entry); c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); } if (!sl) c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); mutex_unlock(&md->list_mutex); return PAGE_SIZE - c; } static ssize_t w1_master_attribute_show_add(struct device *dev, struct device_attribute *attr, char *buf) { int c = PAGE_SIZE; c -= snprintf(buf+PAGE_SIZE - c, c, "write device id xx-xxxxxxxxxxxx to add slave\n"); return PAGE_SIZE - c; } static int w1_atoreg_num(struct device *dev, const char *buf, size_t count, struct w1_reg_num *rn) { unsigned int family; unsigned long long id; int i; u64 rn64_le; /* The CRC value isn't read from the user because the sysfs directory * doesn't include it and most messages from the bus search don't * print it either. It would be unreasonable for the user to then * provide it. */ const char *error_msg = "bad slave string format, expecting " "ff-dddddddddddd\n"; if (buf[2] != '-') { dev_err(dev, "%s", error_msg); return -EINVAL; } i = sscanf(buf, "%02x-%012llx", &family, &id); if (i != 2) { dev_err(dev, "%s", error_msg); return -EINVAL; } rn->family = family; rn->id = id; rn64_le = cpu_to_le64(*(u64 *)rn); rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7); #if 0 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n", rn->family, (unsigned long long)rn->id, rn->crc); #endif return 0; } /* Searches the slaves in the w1_master and returns a pointer or NULL. * Note: must not hold list_mutex */ struct w1_slave *w1_slave_search_device(struct w1_master *dev, struct w1_reg_num *rn) { struct w1_slave *sl; mutex_lock(&dev->list_mutex); list_for_each_entry(sl, &dev->slist, w1_slave_entry) { if (sl->reg_num.family == rn->family && sl->reg_num.id == rn->id && sl->reg_num.crc == rn->crc) { mutex_unlock(&dev->list_mutex); return sl; } } mutex_unlock(&dev->list_mutex); return NULL; } static ssize_t w1_master_attribute_store_add(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct w1_master *md = dev_to_w1_master(dev); struct w1_reg_num rn; struct w1_slave *sl; ssize_t result = count; if (w1_atoreg_num(dev, buf, count, &rn)) return -EINVAL; mutex_lock(&md->mutex); sl = w1_slave_search_device(md, &rn); /* It would be nice to do a targeted search one the one-wire bus * for the new device to see if it is out there or not. But the * current search doesn't support that. */ if (sl) { dev_info(dev, "Device %s already exists\n", sl->name); result = -EINVAL; } else { w1_attach_slave_device(md, &rn); } mutex_unlock(&md->mutex); return result; } static ssize_t w1_master_attribute_show_remove(struct device *dev, struct device_attribute *attr, char *buf) { int c = PAGE_SIZE; c -= snprintf(buf+PAGE_SIZE - c, c, "write device id xx-xxxxxxxxxxxx to remove slave\n"); return PAGE_SIZE - c; } static ssize_t w1_master_attribute_store_remove(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct w1_master *md = dev_to_w1_master(dev); struct w1_reg_num rn; struct w1_slave *sl; ssize_t result = count; if (w1_atoreg_num(dev, buf, count, &rn)) return -EINVAL; mutex_lock(&md->mutex); sl = w1_slave_search_device(md, &rn); if (sl) { result = w1_slave_detach(sl); /* refcnt 0 means it was detached in the call */ if (result == 0) result = count; } else { dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family, (unsigned long long)rn.id); result = -EINVAL; } mutex_unlock(&md->mutex); return result; } #define W1_MASTER_ATTR_RO(_name, _mode) \ struct device_attribute w1_master_attribute_##_name = \ __ATTR(w1_master_##_name, _mode, \ w1_master_attribute_show_##_name, NULL) #define W1_MASTER_ATTR_RW(_name, _mode) \ struct device_attribute w1_master_attribute_##_name = \ __ATTR(w1_master_##_name, _mode, \ w1_master_attribute_show_##_name, \ w1_master_attribute_store_##_name) static W1_MASTER_ATTR_RO(name, S_IRUGO); static W1_MASTER_ATTR_RO(slaves, S_IRUGO); static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP); static W1_MASTER_ATTR_RO(attempts, S_IRUGO); static W1_MASTER_ATTR_RO(timeout, S_IRUGO); static W1_MASTER_ATTR_RO(pointer, S_IRUGO); static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP); static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP); static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP); static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP); static struct attribute *w1_master_default_attrs[] = { &w1_master_attribute_name.attr, &w1_master_attribute_slaves.attr, &w1_master_attribute_slave_count.attr, &w1_master_attribute_max_slave_count.attr, &w1_master_attribute_attempts.attr, &w1_master_attribute_timeout.attr, &w1_master_attribute_pointer.attr, &w1_master_attribute_search.attr, &w1_master_attribute_pullup.attr, &w1_master_attribute_add.attr, &w1_master_attribute_remove.attr, NULL }; static struct attribute_group w1_master_defattr_group = { .attrs = w1_master_default_attrs, }; int w1_create_master_attributes(struct w1_master *master) { return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); } void w1_destroy_master_attributes(struct w1_master *master) { sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); } static int w1_uevent(struct device *dev, struct kobj_uevent_env *env) { struct w1_master *md = NULL; struct w1_slave *sl = NULL; char *event_owner, *name; int err = 0; if (dev->driver == &w1_master_driver) { md = container_of(dev, struct w1_master, dev); event_owner = "master"; name = md->name; } else if (dev->driver == &w1_slave_driver) { sl = container_of(dev, struct w1_slave, dev); event_owner = "slave"; name = sl->name; } else { dev_dbg(dev, "Unknown event.\n"); return -EINVAL; } dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev_name(dev)); if (dev->driver != &w1_slave_driver || !sl) goto end; err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family); if (err) goto end; err = add_uevent_var(env, "W1_SLAVE_ID=%024LX", (unsigned long long)sl->reg_num.id); end: return err; } static int w1_family_notify(unsigned long action, struct w1_slave *sl) { struct w1_family_ops *fops; int err; fops = sl->family->fops; if (!fops) return 0; switch (action) { case BUS_NOTIFY_ADD_DEVICE: /* if the family driver needs to initialize something... */ if (fops->add_slave) { err = fops->add_slave(sl); if (err < 0) { dev_err(&sl->dev, "add_slave() call failed. err=%d\n", err); return err; } } if (fops->groups) { err = sysfs_create_groups(&sl->dev.kobj, fops->groups); if (err) { dev_err(&sl->dev, "sysfs group creation failed. err=%d\n", err); return err; } } break; case BUS_NOTIFY_DEL_DEVICE: if (fops->remove_slave) sl->family->fops->remove_slave(sl); if (fops->groups) sysfs_remove_groups(&sl->dev.kobj, fops->groups); break; } return 0; } static int __w1_attach_slave_device(struct w1_slave *sl) { int err; sl->dev.parent = &sl->master->dev; sl->dev.driver = &w1_slave_driver; sl->dev.bus = &w1_bus_type; sl->dev.release = &w1_slave_release; sl->dev.groups = w1_slave_groups; dev_set_name(&sl->dev, "%02x-%012llx", (unsigned int) sl->reg_num.family, (unsigned long long) sl->reg_num.id); snprintf(&sl->name[0], sizeof(sl->name), "%02x-%012llx", (unsigned int) sl->reg_num.family, (unsigned long long) sl->reg_num.id); dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, dev_name(&sl->dev), sl); /* suppress for w1_family_notify before sending KOBJ_ADD */ dev_set_uevent_suppress(&sl->dev, true); err = device_register(&sl->dev); if (err < 0) { dev_err(&sl->dev, "Device registration [%s] failed. err=%d\n", dev_name(&sl->dev), err); return err; } w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl); dev_set_uevent_suppress(&sl->dev, false); kobject_uevent(&sl->dev.kobj, KOBJ_ADD); mutex_lock(&sl->master->list_mutex); list_add_tail(&sl->w1_slave_entry, &sl->master->slist); mutex_unlock(&sl->master->list_mutex); return 0; } int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) { struct w1_slave *sl; struct w1_family *f; int err; struct w1_netlink_msg msg; sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL); if (!sl) { dev_err(&dev->dev, "%s: failed to allocate new slave device.\n", __func__); return -ENOMEM; } sl->owner = THIS_MODULE; sl->master = dev; set_bit(W1_SLAVE_ACTIVE, &sl->flags); memset(&msg, 0, sizeof(msg)); memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); atomic_set(&sl->refcnt, 1); atomic_inc(&sl->master->refcnt); /* slave modules need to be loaded in a context with unlocked mutex */ mutex_unlock(&dev->mutex); request_module("w1-family-0x%02x", rn->family); mutex_lock(&dev->mutex); spin_lock(&w1_flock); f = w1_family_registered(rn->family); if (!f) { f= &w1_default_family; dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", rn->family, rn->family, (unsigned long long)rn->id, rn->crc); } __w1_family_get(f); spin_unlock(&w1_flock); sl->family = f; err = __w1_attach_slave_device(sl); if (err < 0) { dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, sl->name); w1_family_put(sl->family); kfree(sl); return err; } sl->ttl = dev->slave_ttl; dev->slave_count++; memcpy(msg.id.id, rn, sizeof(msg.id)); msg.type = W1_SLAVE_ADD; w1_netlink_send(dev, &msg); return 0; } int w1_unref_slave(struct w1_slave *sl) { struct w1_master *dev = sl->master; int refcnt; mutex_lock(&dev->list_mutex); refcnt = atomic_sub_return(1, &sl->refcnt); if (refcnt == 0) { struct w1_netlink_msg msg; dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl); list_del(&sl->w1_slave_entry); memset(&msg, 0, sizeof(msg)); memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); msg.type = W1_SLAVE_REMOVE; w1_netlink_send(sl->master, &msg); w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl); device_unregister(&sl->dev); #ifdef DEBUG memset(sl, 0, sizeof(*sl)); #endif kfree(sl); } atomic_dec(&dev->refcnt); mutex_unlock(&dev->list_mutex); return refcnt; } int w1_slave_detach(struct w1_slave *sl) { /* Only detach a slave once as it decreases the refcnt each time. */ int destroy_now; mutex_lock(&sl->master->list_mutex); destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags); set_bit(W1_SLAVE_DETACH, &sl->flags); mutex_unlock(&sl->master->list_mutex); if (destroy_now) destroy_now = !w1_unref_slave(sl); return destroy_now ? 0 : -EBUSY; } struct w1_master *w1_search_master_id(u32 id) { struct w1_master *dev; int found = 0; mutex_lock(&w1_mlock); list_for_each_entry(dev, &w1_masters, w1_master_entry) { if (dev->id == id) { found = 1; atomic_inc(&dev->refcnt); break; } } mutex_unlock(&w1_mlock); return (found)?dev:NULL; } struct w1_slave *w1_search_slave(struct w1_reg_num *id) { struct w1_master *dev; struct w1_slave *sl = NULL; int found = 0; mutex_lock(&w1_mlock); list_for_each_entry(dev, &w1_masters, w1_master_entry) { mutex_lock(&dev->list_mutex); list_for_each_entry(sl, &dev->slist, w1_slave_entry) { if (sl->reg_num.family == id->family && sl->reg_num.id == id->id && sl->reg_num.crc == id->crc) { found = 1; atomic_inc(&dev->refcnt); atomic_inc(&sl->refcnt); break; } } mutex_unlock(&dev->list_mutex); if (found) break; } mutex_unlock(&w1_mlock); return (found)?sl:NULL; } void w1_reconnect_slaves(struct w1_family *f, int attach) { struct w1_slave *sl, *sln; struct w1_master *dev; mutex_lock(&w1_mlock); list_for_each_entry(dev, &w1_masters, w1_master_entry) { dev_dbg(&dev->dev, "Reconnecting slaves in device %s " "for family %02x.\n", dev->name, f->fid); mutex_lock(&dev->mutex); mutex_lock(&dev->list_mutex); list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { /* If it is a new family, slaves with the default * family driver and are that family will be * connected. If the family is going away, devices * matching that family are reconneced. */ if ((attach && sl->family->fid == W1_FAMILY_DEFAULT && sl->reg_num.family == f->fid) || (!attach && sl->family->fid == f->fid)) { struct w1_reg_num rn; mutex_unlock(&dev->list_mutex); memcpy(&rn, &sl->reg_num, sizeof(rn)); /* If it was already in use let the automatic * scan pick it up again later. */ if (!w1_slave_detach(sl)) w1_attach_slave_device(dev, &rn); mutex_lock(&dev->list_mutex); } } dev_dbg(&dev->dev, "Reconnecting slaves in device %s " "has been finished.\n", dev->name); mutex_unlock(&dev->list_mutex); mutex_unlock(&dev->mutex); } mutex_unlock(&w1_mlock); } void w1_slave_found(struct w1_master *dev, u64 rn) { struct w1_slave *sl; struct w1_reg_num *tmp; u64 rn_le = cpu_to_le64(rn); atomic_inc(&dev->refcnt); tmp = (struct w1_reg_num *) &rn; sl = w1_slave_search_device(dev, tmp); if (sl) { set_bit(W1_SLAVE_ACTIVE, &sl->flags); } else { if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7)) w1_attach_slave_device(dev, tmp); } atomic_dec(&dev->refcnt); } /** * w1_search() - Performs a ROM Search & registers any devices found. * @dev: The master device to search * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH * to return only devices in the alarmed state * @cb: Function to call when a device is found * * The 1-wire search is a simple binary tree search. * For each bit of the address, we read two bits and write one bit. * The bit written will put to sleep all devies that don't match that bit. * When the two reads differ, the direction choice is obvious. * When both bits are 0, we must choose a path to take. * When we can scan all 64 bits without having to choose a path, we are done. * * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com * */ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) { u64 last_rn, rn, tmp64; int i, slave_count = 0; int last_zero, last_device; int search_bit, desc_bit; u8 triplet_ret = 0; search_bit = 0; rn = dev->search_id; last_rn = 0; last_device = 0; last_zero = -1; desc_bit = 64; while ( !last_device && (slave_count++ < dev->max_slave_count) ) { last_rn = rn; rn = 0; /* * Reset bus and all 1-wire device state machines * so they can respond to our requests. * * Return 0 - device(s) present, 1 - no devices present. */ mutex_lock(&dev->bus_mutex); if (w1_reset_bus(dev)) { mutex_unlock(&dev->bus_mutex); dev_dbg(&dev->dev, "No devices present on the wire.\n"); break; } /* Do fast search on single slave bus */ if (dev->max_slave_count == 1) { int rv; w1_write_8(dev, W1_READ_ROM); rv = w1_read_block(dev, (u8 *)&rn, 8); mutex_unlock(&dev->bus_mutex); if (rv == 8 && rn) cb(dev, rn); break; } /* Start the search */ w1_write_8(dev, search_type); for (i = 0; i < 64; ++i) { /* Determine the direction/search bit */ if (i == desc_bit) search_bit = 1; /* took the 0 path last time, so take the 1 path */ else if (i > desc_bit) search_bit = 0; /* take the 0 path on the next branch */ else search_bit = ((last_rn >> i) & 0x1); /* Read two bits and write one bit */ triplet_ret = w1_triplet(dev, search_bit); /* quit if no device responded */ if ( (triplet_ret & 0x03) == 0x03 ) break; /* If both directions were valid, and we took the 0 path... */ if (triplet_ret == 0) last_zero = i; /* extract the direction taken & update the device number */ tmp64 = (triplet_ret >> 2); rn |= (tmp64 << i); if (test_bit(W1_ABORT_SEARCH, &dev->flags)) { mutex_unlock(&dev->bus_mutex); dev_dbg(&dev->dev, "Abort w1_search\n"); return; } } mutex_unlock(&dev->bus_mutex); if ( (triplet_ret & 0x03) != 0x03 ) { if ((desc_bit == last_zero) || (last_zero < 0)) { last_device = 1; dev->search_id = 0; } else { dev->search_id = rn; } desc_bit = last_zero; cb(dev, rn); } if (!last_device && slave_count == dev->max_slave_count && !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) { /* Only max_slave_count will be scanned in a search, * but it will start where it left off next search * until all ids are identified and then it will start * over. A continued search will report the previous * last id as the first id (provided it is still on the * bus). */ dev_info(&dev->dev, "%s: max_slave_count %d reached, " "will continue next search.\n", __func__, dev->max_slave_count); set_bit(W1_WARN_MAX_COUNT, &dev->flags); } } } void w1_search_process_cb(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) { struct w1_slave *sl, *sln; mutex_lock(&dev->list_mutex); list_for_each_entry(sl, &dev->slist, w1_slave_entry) clear_bit(W1_SLAVE_ACTIVE, &sl->flags); mutex_unlock(&dev->list_mutex); w1_search_devices(dev, search_type, cb); mutex_lock(&dev->list_mutex); list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) { mutex_unlock(&dev->list_mutex); w1_slave_detach(sl); mutex_lock(&dev->list_mutex); } else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags)) sl->ttl = dev->slave_ttl; } mutex_unlock(&dev->list_mutex); if (dev->search_count > 0) dev->search_count--; } static void w1_search_process(struct w1_master *dev, u8 search_type) { w1_search_process_cb(dev, search_type, w1_slave_found); } /** * w1_process_callbacks() - execute each dev->async_list callback entry * @dev: w1_master device * * The w1 master list_mutex must be held. * * Return: 1 if there were commands to executed 0 otherwise */ int w1_process_callbacks(struct w1_master *dev) { int ret = 0; struct w1_async_cmd *async_cmd, *async_n; /* The list can be added to in another thread, loop until it is empty */ while (!list_empty(&dev->async_list)) { list_for_each_entry_safe(async_cmd, async_n, &dev->async_list, async_entry) { /* drop the lock, if it is a search it can take a long * time */ mutex_unlock(&dev->list_mutex); async_cmd->cb(dev, async_cmd); ret = 1; mutex_lock(&dev->list_mutex); } } return ret; } int w1_process(void *data) { struct w1_master *dev = (struct w1_master *) data; /* As long as w1_timeout is only set by a module parameter the sleep * time can be calculated in jiffies once. */ const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000); /* remainder if it woke up early */ unsigned long jremain = 0; for (;;) { if (!jremain && dev->search_count) { mutex_lock(&dev->mutex); w1_search_process(dev, W1_SEARCH); mutex_unlock(&dev->mutex); } mutex_lock(&dev->list_mutex); /* Note, w1_process_callback drops the lock while processing, * but locks it again before returning. */ if (!w1_process_callbacks(dev) && jremain) { /* a wake up is either to stop the thread, process * callbacks, or search, it isn't process callbacks, so * schedule a search. */ jremain = 1; } try_to_freeze(); __set_current_state(TASK_INTERRUPTIBLE); /* hold list_mutex until after interruptible to prevent loosing * the wakeup signal when async_cmd is added. */ mutex_unlock(&dev->list_mutex); if (kthread_should_stop()) break; /* Only sleep when the search is active. */ if (dev->search_count) { if (!jremain) jremain = jtime; jremain = schedule_timeout(jremain); } else schedule(); } atomic_dec(&dev->refcnt); return 0; } static int __init w1_init(void) { int retval; pr_info("Driver for 1-wire Dallas network protocol.\n"); w1_init_netlink(); retval = bus_register(&w1_bus_type); if (retval) { pr_err("Failed to register bus. err=%d.\n", retval); goto err_out_exit_init; } retval = driver_register(&w1_master_driver); if (retval) { pr_err("Failed to register master driver. err=%d.\n", retval); goto err_out_bus_unregister; } retval = driver_register(&w1_slave_driver); if (retval) { pr_err("Failed to register slave driver. err=%d.\n", retval); goto err_out_master_unregister; } return 0; #if 0 /* For undoing the slave register if there was a step after it. */ err_out_slave_unregister: driver_unregister(&w1_slave_driver); #endif err_out_master_unregister: driver_unregister(&w1_master_driver); err_out_bus_unregister: bus_unregister(&w1_bus_type); err_out_exit_init: return retval; } static void __exit w1_fini(void) { struct w1_master *dev; /* Set netlink removal messages and some cleanup */ list_for_each_entry(dev, &w1_masters, w1_master_entry) __w1_remove_master_device(dev); w1_fini_netlink(); driver_unregister(&w1_slave_driver); driver_unregister(&w1_master_driver); bus_unregister(&w1_bus_type); } module_init(w1_init); module_exit(w1_fini);