linux-stable/drivers/w1/w1.c
Andrew F. Davis 91bd2855ed w1: Remove unneeded use of assert() and remove w1_log.h
The only use of assert() is in matrox_w1.c and is used to check the input
to probe() from the PCI subsystem for NULL values, these are guaranteed
to be populated and no other PCI driver makes this check, remove this.

As this was the only definition in w1_log.h, remove this also.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-08 18:20:57 +02:00

1230 lines
30 KiB
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.
*/
#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_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_us,
"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) || 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);
atomic_dec(&sl->master->refcnt);
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;
}
__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);