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linux-stable/drivers/w1/w1.c
Dmitry Khromov c309835692 w1: introduce an ability to specify microseconds bus scanning intervals 
Some of 1-Wire devices commonly associated with physical access control
systems are attached/generate presence for as short as 100 ms - hence
the tens-to-hundreds milliseconds scan intervals are required.

Signed-off-by: Dmitry Khromov <dk@icelogic.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 12:08:59 -07:00

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/*
* w1.c
*
* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
*
*
* 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 <linux/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 <zbr@ioremap.net>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
static int w1_timeout = 10;
static int w1_timeout_us = 0;
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");
module_param_named(timeout_us, w1_timeout_us, int, 0);
MODULE_PARM_DESC(timeout, "time in microseconds 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_show_timeout_us(struct device *dev,
struct device_attribute *attr, char *buf)
{
ssize_t count;
count = sprintf(buf, "%d\n", w1_timeout_us);
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(timeout_us, 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_timeout_us.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 =
usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);
/* 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);
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