linux/drivers/w1/w1.c

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/*
* 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;
static int w1_control_timeout = 1;
int w1_max_slave_count = 10;
int w1_max_slave_ttl = 10;
module_param_named(timeout, w1_timeout, int, 0);
module_param_named(control_timeout, w1_control_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 struct task_struct *w1_control_thread;
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);
printk("%s: Releasing %s.\n", __func__, sl->name);
while (atomic_read(&sl->refcnt)) {
printk("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);
}
sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes Well, first of all, I don't want to change so many files either. What I do: Adding a new parameter "struct bin_attribute *" in the .read/.write methods for the sysfs binary attributes. In fact, only the four lines change in fs/sysfs/bin.c and include/linux/sysfs.h do the real work. But I have to update all the files that use binary attributes to make them compatible with the new .read and .write methods. I'm not sure if I missed any. :( Why I do this: For a sysfs attribute, we can get a pointer pointing to the struct attribute in the .show/.store method, while we can't do this for the binary attributes. I don't know why this is different, but this does make it not so handy to use the binary attributes as the regular ones. So I think this patch is reasonable. :) Who benefits from it: The patch that exposes ACPI tables in sysfs requires such an improvement. All the table binary attributes share the same .read method. Parameter "struct bin_attribute *" is used to get the table signature and instance number which are used to distinguish different ACPI table binary attributes. Without this parameter, we need to offer different .read methods for different ACPI table binary attributes. This is impossible as there are various ACPI tables on different platforms, and we don't know what they are until they are loaded. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-09 05:57:22 +00:00
static ssize_t w1_slave_read_id(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);
if (off > 8) {
count = 0;
} else {
if (off + count > 8)
count = 8 - off;
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 bin_attribute w1_slave_attr_bin_id = {
.attr = {
.name = "id",
.mode = S_IRUGO,
},
.size = 8,
.read = w1_slave_read_id,
};
/* Default family */
sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes Well, first of all, I don't want to change so many files either. What I do: Adding a new parameter "struct bin_attribute *" in the .read/.write methods for the sysfs binary attributes. In fact, only the four lines change in fs/sysfs/bin.c and include/linux/sysfs.h do the real work. But I have to update all the files that use binary attributes to make them compatible with the new .read and .write methods. I'm not sure if I missed any. :( Why I do this: For a sysfs attribute, we can get a pointer pointing to the struct attribute in the .show/.store method, while we can't do this for the binary attributes. I don't know why this is different, but this does make it not so handy to use the binary attributes as the regular ones. So I think this patch is reasonable. :) Who benefits from it: The patch that exposes ACPI tables in sysfs requires such an improvement. All the table binary attributes share the same .read method. Parameter "struct bin_attribute *" is used to get the table signature and instance number which are used to distinguish different ACPI table binary attributes. Without this parameter, we need to offer different .read methods for different ACPI table binary attributes. This is impossible as there are various ACPI tables on different platforms, and we don't know what they are until they are loaded. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-09 05:57:22 +00:00
static ssize_t w1_default_write(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;
}
sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes Well, first of all, I don't want to change so many files either. What I do: Adding a new parameter "struct bin_attribute *" in the .read/.write methods for the sysfs binary attributes. In fact, only the four lines change in fs/sysfs/bin.c and include/linux/sysfs.h do the real work. But I have to update all the files that use binary attributes to make them compatible with the new .read and .write methods. I'm not sure if I missed any. :( Why I do this: For a sysfs attribute, we can get a pointer pointing to the struct attribute in the .show/.store method, while we can't do this for the binary attributes. I don't know why this is different, but this does make it not so handy to use the binary attributes as the regular ones. So I think this patch is reasonable. :) Who benefits from it: The patch that exposes ACPI tables in sysfs requires such an improvement. All the table binary attributes share the same .read method. Parameter "struct bin_attribute *" is used to get the table signature and instance number which are used to distinguish different ACPI table binary attributes. Without this parameter, we need to offer different .read methods for different ACPI table binary attributes. This is impossible as there are various ACPI tables on different platforms, and we don't know what they are until they are loaded. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-09 05:57:22 +00:00
static ssize_t w1_default_read(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, char **envp, int num_envp, char *buffer, int buffer_size);
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,
.bus_id = "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,
.bus_id = "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)
{
struct w1_master *md = dev_to_w1_master(dev);
mutex_lock(&md->mutex);
md->search_count = simple_strtol(buf, NULL, 0);
mutex_unlock(&md->mutex);
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_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;
}
#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_IWUGO);
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,
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);
}
static 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, char **envp, int num_envp,
char *buffer, int buffer_size)
{
struct w1_master *md = NULL;
struct w1_slave *sl = NULL;
char *event_owner, *name;
int err, cur_index=0, cur_len=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->bus_id);
if (dev->driver != &w1_slave_driver || !sl)
return 0;
err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
&cur_len, "W1_FID=%02X", sl->reg_num.family);
if (err)
return err;
err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
&cur_len, "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, char **envp, int num_envp,
char *buffer, int buffer_size)
{
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;
snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
"%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__,
&sl->dev.bus_id[0], sl);
err = device_register(&sl->dev);
if (err < 0) {
dev_err(&sl->dev,
"Device registration [%s] failed. err=%d\n",
sl->dev.bus_id, 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",
sl->dev.bus_id, err);
goto out_unreg;
}
/* Create "id" entry */
err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
if (err < 0) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
sl->dev.bus_id, 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",
sl->dev.bus_id, err);
goto out_rem2;
}
list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
return 0;
out_rem2:
sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_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;
2007-07-19 08:49:03 +00:00
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;
}
static 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);
sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
device_remove_file(&sl->dev, &w1_slave_attr_name);
device_unregister(&sl->dev);
wait_for_completion(&sl->released);
kfree(sl);
}
static struct w1_master *w1_search_master(void *data)
{
struct w1_master *dev;
int found = 0;
mutex_lock(&w1_mlock);
list_for_each_entry(dev, &w1_masters, w1_master_entry) {
if (dev->bus_master->data == data) {
found = 1;
atomic_inc(&dev->refcnt);
break;
}
}
mutex_unlock(&w1_mlock);
return (found)?dev:NULL;
}
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)
{
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 %s into new family %02x.\n",
dev->name, f->fid);
set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
}
mutex_unlock(&w1_mlock);
}
static void w1_slave_found(void *data, u64 rn)
{
int slave_count;
struct w1_slave *sl;
struct list_head *ent;
struct w1_reg_num *tmp;
int family_found = 0;
struct w1_master *dev;
u64 rn_le = cpu_to_le64(rn);
dev = w1_search_master(data);
if (!dev) {
printk(KERN_ERR "Failed to find w1 master device for data %p, "
"it is impossible.\n", data);
return;
}
tmp = (struct w1_reg_num *) &rn;
slave_count = 0;
list_for_each(ent, &dev->slist) {
sl = list_entry(ent, struct w1_slave, w1_slave_entry);
if (sl->reg_num.family == tmp->family &&
sl->reg_num.id == tmp->id &&
sl->reg_num.crc == tmp->crc) {
set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
break;
} else if (sl->reg_num.family == tmp->family) {
family_found = 1;
break;
}
slave_count++;
}
if (slave_count == dev->slave_count &&
rn && ((rn >> 56) & 0xff) == 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 ( (triplet_ret & 0x03) != 0x03 ) {
if ( (desc_bit == last_zero) || (last_zero < 0))
last_device = 1;
desc_bit = last_zero;
cb(dev->bus_master->data, rn);
}
}
}
static int w1_control(void *data)
{
struct w1_slave *sl, *sln;
struct w1_master *dev, *n;
int have_to_wait = 0;
set_freezable();
while (!kthread_should_stop() || have_to_wait) {
have_to_wait = 0;
try_to_freeze();
msleep_interruptible(w1_control_timeout * 1000);
list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
if (!kthread_should_stop() && !dev->flags)
continue;
/*
* Little race: we can create thread but not set the flag.
* Get a chance for external process to set flag up.
*/
if (!dev->initialized) {
have_to_wait = 1;
continue;
}
if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
mutex_lock(&w1_mlock);
list_del(&dev->w1_master_entry);
mutex_unlock(&w1_mlock);
mutex_lock(&dev->mutex);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
w1_slave_detach(sl);
}
w1_destroy_master_attributes(dev);
mutex_unlock(&dev->mutex);
atomic_dec(&dev->refcnt);
continue;
}
if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
mutex_lock(&dev->mutex);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
if (sl->family->fid == W1_FAMILY_DEFAULT) {
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);
clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
mutex_unlock(&dev->mutex);
}
}
}
return 0;
}
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);
dev->slave_count--;
} 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;
while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
try_to_freeze();
msleep_interruptible(w1_timeout * 1000);
if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
break;
if (!dev->initialized)
continue;
if (dev->search_count == 0)
continue;
mutex_lock(&dev->mutex);
w1_search_process(dev, W1_SEARCH);
mutex_unlock(&dev->mutex);
}
atomic_dec(&dev->refcnt);
return 0;
}
static int 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;
}
w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
if (IS_ERR(w1_control_thread)) {
retval = PTR_ERR(w1_control_thread);
printk(KERN_ERR "Failed to create control thread. err=%d\n",
retval);
goto err_out_slave_unregister;
}
return 0;
err_out_slave_unregister:
driver_unregister(&w1_slave_driver);
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 w1_fini(void)
{
struct w1_master *dev;
list_for_each_entry(dev, &w1_masters, w1_master_entry)
__w1_remove_master_device(dev);
w1_fini_netlink();
kthread_stop(w1_control_thread);
driver_unregister(&w1_slave_driver);
driver_unregister(&w1_master_driver);
bus_unregister(&w1_bus_type);
}
module_init(w1_init);
module_exit(w1_fini);