text: /*
   *	w1.c
   *
   * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   *
   *
   * 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 <linux/delay.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/list.h>
  #include <linux/interrupt.h>
  #include <linux/spinlock.h>
  #include <linux/timer.h>
  #include <linux/device.h>
  #include <linux/slab.h>
  #include <linux/sched.h>
  #include <linux/kthread.h>
  #include <linux/freezer.h>
  
  #include <asm/atomic.h>
  
  #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 <johnpol@2ka.mipt.ru>");
  MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  
  static int w1_timeout = 10;
  int w1_max_slave_count = 10;
  int w1_max_slave_ttl = 10;
  
  module_param_named(timeout, w1_timeout, int, 0);
  module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  
  DEFINE_MUTEX(w1_mlock);
  LIST_HEAD(w1_masters);
  
  static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
  
  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.\n", __func__, sl->name);
  
  	while (atomic_read(&sl->refcnt)) {
  		dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
  				sl->name, atomic_read(&sl->refcnt));
  		if (msleep_interruptible(1000))
  			flush_signals(current);
  	}
  
  	w1_family_put(sl->family);
  	sl->master->slave_count--;
  
  	complete(&sl->released);
  }
  
  static ssize_t w1_slave_read_name(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 ssize_t w1_slave_read_id(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 struct device_attribute w1_slave_attr_name =
  	__ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
  static struct device_attribute w1_slave_attr_id =
  	__ATTR(id, S_IRUGO, w1_slave_read_id, NULL);
  
  /* Default family */
  
  static ssize_t w1_default_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 w1_default_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 struct bin_attribute w1_default_attr = {
        .attr = {
                .name = "rw",
                .mode = S_IRUGO | S_IWUSR,
        },
        .size = PAGE_SIZE,
        .read = w1_default_read,
        .write = w1_default_write,
  };
  
  static int w1_default_add_slave(struct w1_slave *sl)
  {
  	return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
  }
  
  static void w1_default_remove_slave(struct w1_slave *sl)
  {
  	sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
  }
  
  static struct w1_family_ops w1_default_fops = {
  	.add_slave	= w1_default_add_slave,
  	.remove_slave	= w1_default_remove_slave,
  };
  
  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);
  
  	if (strict_strtol(buf, 0, &tmp) == -EINVAL)
  		return -EINVAL;
  
  	mutex_lock(&md->mutex);
  	md->search_count = tmp;
  	mutex_unlock(&md->mutex);
  	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);
  
  	if (strict_strtol(buf, 0, &tmp) == -EINVAL)
  		return -EINVAL;
  
  	mutex_lock(&md->mutex);
  	md->enable_pullup = tmp;
  	mutex_unlock(&md->mutex);
  	wake_up_process(md->thread);
  
  	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_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;
  
  	mutex_lock(&md->mutex);
  
  	if (md->slave_count == 0)
  		c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
  	else {
  		struct list_head *ent, *n;
  		struct w1_slave *sl;
  
  		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);
  		}
  	}
  
  	mutex_unlock(&md->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 hold the mutex
   */
  static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
  	struct w1_reg_num *rn)
  {
  	struct w1_slave *sl;
  	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) {
  			return sl;
  		}
  	}
  	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) {
  		w1_slave_detach(sl);
  	} 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_RO(max_slave_count, S_IRUGO);
  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);
  }
  
  #ifdef CONFIG_HOTPLUG
  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;
  
  	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)
  		return 0;
  
  	err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
  	if (err)
  		return err;
  
  	err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
  			     (unsigned long long)sl->reg_num.id);
  	if (err)
  		return err;
  
  	return 0;
  };
  #else
  static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	return 0;
  }
  #endif
  
  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;
  
  	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);
  
  	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;
  	}
  
  	/* Create "name" entry */
  	err = device_create_file(&sl->dev, &w1_slave_attr_name);
  	if (err < 0) {
  		dev_err(&sl->dev,
  			"sysfs file creation for [%s] failed. err=%d\n",
  			dev_name(&sl->dev), err);
  		goto out_unreg;
  	}
  
  	/* Create "id" entry */
  	err = device_create_file(&sl->dev, &w1_slave_attr_id);
  	if (err < 0) {
  		dev_err(&sl->dev,
  			"sysfs file creation for [%s] failed. err=%d\n",
  			dev_name(&sl->dev), err);
  		goto out_rem1;
  	}
  
  	/* if the family driver needs to initialize something... */
  	if (sl->family->fops && sl->family->fops->add_slave &&
  	    ((err = sl->family->fops->add_slave(sl)) < 0)) {
  		dev_err(&sl->dev,
  			"sysfs file creation for [%s] failed. err=%d\n",
  			dev_name(&sl->dev), err);
  		goto out_rem2;
  	}
  
  	list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
  
  	return 0;
  
  out_rem2:
  	device_remove_file(&sl->dev, &w1_slave_attr_id);
  out_rem1:
  	device_remove_file(&sl->dev, &w1_slave_attr_name);
  out_unreg:
  	device_unregister(&sl->dev);
  	return err;
  }
  
  static 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, (long *)&sl->flags);
  
  	memset(&msg, 0, sizeof(msg));
  	memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
  	atomic_set(&sl->refcnt, 0);
  	init_completion(&sl->released);
  
  	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;
  }
  
  void w1_slave_detach(struct w1_slave *sl)
  {
  	struct w1_netlink_msg msg;
  
  	dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
  
  	list_del(&sl->w1_slave_entry);
  
  	if (sl->family->fops && sl->family->fops->remove_slave)
  		sl->family->fops->remove_slave(sl);
  
  	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);
  
  	device_remove_file(&sl->dev, &w1_slave_attr_id);
  	device_remove_file(&sl->dev, &w1_slave_attr_name);
  	device_unregister(&sl->dev);
  
  	wait_for_completion(&sl->released);
  	kfree(sl);
  }
  
  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->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->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);
  		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;
  
  				memcpy(&rn, &sl->reg_num, sizeof(rn));
  				w1_slave_detach(sl);
  
  				w1_attach_slave_device(dev, &rn);
  			}
  		}
  		dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
  			"has been finished.\n", dev->name);
  		mutex_unlock(&dev->mutex);
  	}
  	mutex_unlock(&w1_mlock);
  }
  
  static 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, (long *)&sl->flags);
  	} else {
  		if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
  			w1_attach_slave_device(dev, tmp);
  	}
  
  	atomic_dec(&dev->refcnt);
  }
  
  /**
   * Performs a ROM Search & registers any devices 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
   *
   * @dev        The master device to search
   * @cb         Function to call when a device is found
   */
  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 = 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.
  		 */
  		if (w1_reset_bus(dev)) {
  			dev_dbg(&dev->dev, "No devices present on the wire.\n");
  			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 (kthread_should_stop()) {
  				dev_dbg(&dev->dev, "Abort w1_search\n");
  				return;
  			}
  		}
  
  		if ( (triplet_ret & 0x03) != 0x03 ) {
  			if ( (desc_bit == last_zero) || (last_zero < 0))
  				last_device = 1;
  			desc_bit = last_zero;
  			cb(dev, rn);
  		}
  	}
  }
  
  void w1_search_process(struct w1_master *dev, u8 search_type)
  {
  	struct w1_slave *sl, *sln;
  
  	list_for_each_entry(sl, &dev->slist, w1_slave_entry)
  		clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
  
  	w1_search_devices(dev, search_type, w1_slave_found);
  
  	list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
  		if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
  			w1_slave_detach(sl);
  		else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
  			sl->ttl = dev->slave_ttl;
  	}
  
  	if (dev->search_count > 0)
  		dev->search_count--;
  }
  
  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);
  
  	while (!kthread_should_stop()) {
  		if (dev->search_count) {
  			mutex_lock(&dev->mutex);
  			w1_search_process(dev, W1_SEARCH);
  			mutex_unlock(&dev->mutex);
  		}
  
  		try_to_freeze();
  		__set_current_state(TASK_INTERRUPTIBLE);
  
  		if (kthread_should_stop())
  			break;
  
  		/* Only sleep when the search is active. */
  		if (dev->search_count)
  			schedule_timeout(jtime);
  		else
  			schedule();
  	}
  
  	atomic_dec(&dev->refcnt);
  
  	return 0;
  }
  
  static int __init w1_init(void)
  {
  	int retval;
  
  	printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
  
  	w1_init_netlink();
  
  	retval = bus_register(&w1_bus_type);
  	if (retval) {
  		printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
  		goto err_out_exit_init;
  	}
  
  	retval = driver_register(&w1_master_driver);
  	if (retval) {
  		printk(KERN_ERR
  			"Failed to register master driver. err=%d.\n",
  			retval);
  		goto err_out_bus_unregister;
  	}
  
  	retval = driver_register(&w1_slave_driver);
  	if (retval) {
  		printk(KERN_ERR
  			"Failed to register master 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);
  