linux/drivers/w1/w1.c
Evgeniy Polyakov 6adf87bd7b [PATCH] w1: reconnect feature.
I've created reconnect feature - if on start there are no registered families
all new devices will have defailt family, later when driver for appropriate
family is loaded, slaves, which were faound earlier, will still have defult
family instead of right one. Reconnect feature will force control thread to run
through all master devices and all slaves found and search for slaves with
default family id and try to reconnect them.

It does not store newly registered family and does not check only those slaves
which have reg_num.family the same as being registered one - all slaves with
default family are reconnected.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-06-21 21:43:12 -07:00

830 lines
20 KiB
C

/*
* 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 <asm/atomic.h>
#include "w1.h"
#include "w1_io.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_SPINLOCK(w1_mlock);
LIST_HEAD(w1_masters);
static pid_t control_thread;
static int control_needs_exit;
static DECLARE_COMPLETION(w1_control_complete);
/* stuff for the default family */
static ssize_t w1_famdefault_read_name(struct device *dev, struct device_attribute *attr, char *buf)
{
struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
return(sprintf(buf, "%s\n", sl->name));
}
static struct w1_family_ops w1_default_fops = {
.rname = &w1_famdefault_read_name,
};
static struct w1_family w1_default_family = {
.fops = &w1_default_fops,
};
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 int w1_master_remove(struct device *dev)
{
return 0;
}
static void w1_master_release(struct device *dev)
{
struct w1_master *md = container_of(dev, struct w1_master, dev);
complete(&md->dev_released);
}
static void w1_slave_release(struct device *dev)
{
struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
complete(&sl->dev_released);
}
static ssize_t w1_default_read_name(struct device *dev, struct device_attribute *attr, char *buf)
{
return sprintf(buf, "No family registered.\n");
}
static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off,
size_t count)
{
return sprintf(buf, "No family registered.\n");
}
static struct device_attribute w1_slave_attribute =
__ATTR(name, S_IRUGO, w1_default_read_name, NULL);
static struct bin_attribute w1_slave_bin_attribute = {
.attr = {
.name = "w1_slave",
.mode = S_IRUGO,
.owner = THIS_MODULE,
},
.size = W1_SLAVE_DATA_SIZE,
.read = &w1_default_read_bin,
};
static struct bus_type w1_bus_type = {
.name = "w1",
.match = w1_master_match,
};
struct device_driver w1_driver = {
.name = "w1_driver",
.bus = &w1_bus_type,
.probe = w1_master_probe,
.remove = w1_master_remove,
};
struct device w1_device = {
.parent = NULL,
.bus = &w1_bus_type,
.bus_id = "w1 bus master",
.driver = &w1_driver,
.release = &w1_master_release
};
static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
{
struct w1_master *md = container_of(dev, struct w1_master, dev);
ssize_t count;
if (down_interruptible (&md->mutex))
return -EBUSY;
count = sprintf(buf, "%s\n", md->name);
up(&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 = container_of(dev, struct w1_master, dev);
if (down_interruptible (&md->mutex))
return -EBUSY;
md->search_count = simple_strtol(buf, NULL, 0);
up(&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 = container_of(dev, struct w1_master, dev);
ssize_t count;
if (down_interruptible (&md->mutex))
return -EBUSY;
count = sprintf(buf, "%d\n", md->search_count);
up(&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 = container_of(dev, struct w1_master, dev);
ssize_t count;
if (down_interruptible(&md->mutex))
return -EBUSY;
count = sprintf(buf, "0x%p\n", md->bus_master);
up(&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 = container_of(dev, struct w1_master, dev);
ssize_t count;
if (down_interruptible(&md->mutex))
return -EBUSY;
count = sprintf(buf, "%d\n", md->max_slave_count);
up(&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 = container_of(dev, struct w1_master, dev);
ssize_t count;
if (down_interruptible(&md->mutex))
return -EBUSY;
count = sprintf(buf, "%lu\n", md->attempts);
up(&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 = container_of(dev, struct w1_master, dev);
ssize_t count;
if (down_interruptible(&md->mutex))
return -EBUSY;
count = sprintf(buf, "%d\n", md->slave_count);
up(&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 = container_of(dev, struct w1_master, dev);
int c = PAGE_SIZE;
if (down_interruptible(&md->mutex))
return -EBUSY;
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);
}
}
up(&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);
}
void w1_destroy_master_attributes(struct w1_master *master)
{
sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
}
static int __w1_attach_slave_device(struct w1_slave *sl)
{
int err;
sl->dev.parent = &sl->master->dev;
sl->dev.driver = sl->master->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.\n", __func__,
&sl->dev.bus_id[0]);
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;
}
memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
sl->attr_bin.read = sl->family->fops->rbin;
sl->attr_name.show = sl->family->fops->rname;
err = device_create_file(&sl->dev, &sl->attr_name);
if (err < 0) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
sl->dev.bus_id, err);
device_unregister(&sl->dev);
return err;
}
if ( sl->attr_bin.read ) {
err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
if (err < 0) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
sl->dev.bus_id, err);
device_remove_file(&sl->dev, &sl->attr_name);
device_unregister(&sl->dev);
return err;
}
}
list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
return 0;
}
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 = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
if (!sl) {
dev_err(&dev->dev,
"%s: failed to allocate new slave device.\n",
__func__);
return -ENOMEM;
}
memset(sl, 0, sizeof(*sl));
sl->owner = THIS_MODULE;
sl->master = dev;
set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
atomic_set(&sl->refcnt, 0);
init_completion(&sl->dev_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.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_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
while (atomic_read(&sl->refcnt)) {
printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
sl->name, atomic_read(&sl->refcnt));
if (msleep_interruptible(1000))
flush_signals(current);
}
if ( sl->attr_bin.read ) {
sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
}
device_remove_file(&sl->dev, &sl->attr_name);
device_unregister(&sl->dev);
w1_family_put(sl->family);
sl->master->slave_count--;
memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
msg.type = W1_SLAVE_REMOVE;
w1_netlink_send(sl->master, &msg);
}
static struct w1_master *w1_search_master(unsigned long data)
{
struct w1_master *dev;
int found = 0;
spin_lock_bh(&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;
}
}
spin_unlock_bh(&w1_mlock);
return (found)?dev:NULL;
}
void w1_reconnect_slaves(struct w1_family *f)
{
struct w1_master *dev;
spin_lock_bh(&w1_mlock);
list_for_each_entry(dev, &w1_masters, w1_master_entry) {
dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
dev->name, f->fid);
set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
}
spin_unlock_bh(&w1_mlock);
}
static void w1_slave_found(unsigned long 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;
dev = w1_search_master(data);
if (!dev) {
printk(KERN_ERR "Failed to find w1 master device for data %08lx, 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++;
}
rn = cpu_to_le64(rn);
if (slave_count == dev->slave_count &&
rn && ((le64_to_cpu(rn) >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn, 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, 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_info(&dev->dev, "No devices present on the wire.\n");
break;
}
/* Start the search */
w1_write_8(dev, W1_SEARCH);
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 err, have_to_wait = 0;
daemonize("w1_control");
allow_signal(SIGTERM);
while (!control_needs_exit || have_to_wait) {
have_to_wait = 0;
try_to_freeze(PF_FREEZE);
msleep_interruptible(w1_timeout * 1000);
if (signal_pending(current))
flush_signals(current);
list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
if (!control_needs_exit && !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 (control_needs_exit) {
set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
err = kill_proc(dev->kpid, SIGTERM, 1);
if (err)
dev_err(&dev->dev,
"Failed to send signal to w1 kernel thread %d.\n",
dev->kpid);
}
if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
wait_for_completion(&dev->dev_exited);
spin_lock_bh(&w1_mlock);
list_del(&dev->w1_master_entry);
spin_unlock_bh(&w1_mlock);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
list_del(&sl->w1_slave_entry);
w1_slave_detach(sl);
kfree(sl);
}
w1_destroy_master_attributes(dev);
atomic_dec(&dev->refcnt);
continue;
}
if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
down(&dev->mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
if (sl->family->fid == W1_FAMILY_DEFAULT) {
struct w1_reg_num rn;
list_del(&sl->w1_slave_entry);
w1_slave_detach(sl);
memcpy(&rn, &sl->reg_num, sizeof(rn));
kfree(sl);
w1_attach_slave_device(dev, &rn);
}
}
clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
up(&dev->mutex);
}
}
}
complete_and_exit(&w1_control_complete, 0);
}
int w1_process(void *data)
{
struct w1_master *dev = (struct w1_master *) data;
struct w1_slave *sl, *sln;
daemonize("%s", dev->name);
allow_signal(SIGTERM);
while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
try_to_freeze(PF_FREEZE);
msleep_interruptible(w1_timeout * 1000);
if (signal_pending(current))
flush_signals(current);
if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
break;
if (!dev->initialized)
continue;
if (dev->search_count == 0)
continue;
if (down_interruptible(&dev->mutex))
continue;
list_for_each_entry(sl, &dev->slist, w1_slave_entry)
clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
w1_search_devices(dev, 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) {
list_del (&sl->w1_slave_entry);
w1_slave_detach (sl);
kfree (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--;
up(&dev->mutex);
}
atomic_dec(&dev->refcnt);
complete_and_exit(&dev->dev_exited, 0);
return 0;
}
static int w1_init(void)
{
int retval;
printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
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_driver);
if (retval) {
printk(KERN_ERR
"Failed to register master driver. err=%d.\n",
retval);
goto err_out_bus_unregister;
}
control_thread = kernel_thread(&w1_control, NULL, 0);
if (control_thread < 0) {
printk(KERN_ERR "Failed to create control thread. err=%d\n",
control_thread);
retval = control_thread;
goto err_out_driver_unregister;
}
return 0;
err_out_driver_unregister:
driver_unregister(&w1_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);
control_needs_exit = 1;
wait_for_completion(&w1_control_complete);
driver_unregister(&w1_driver);
bus_unregister(&w1_bus_type);
}
module_init(w1_init);
module_exit(w1_fini);