linux/drivers/w1/w1.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

836 lines
19 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);
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, 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 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 struct device_attribute w1_slave_attribute = {
.attr = {
.name = "name",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_default_read_name,
};
static struct device_attribute w1_slave_attribute_val = {
.attr = {
.name = "value",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_default_read_name,
};
static ssize_t w1_master_attribute_show_name(struct device *dev, 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_show_pointer(struct device *dev, 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, 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, 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, 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, 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, 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;
}
static struct device_attribute w1_master_attribute_slaves = {
.attr = {
.name = "w1_master_slaves",
.mode = S_IRUGO,
.owner = THIS_MODULE,
},
.show = &w1_master_attribute_show_slaves,
};
static struct device_attribute w1_master_attribute_slave_count = {
.attr = {
.name = "w1_master_slave_count",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_master_attribute_show_slave_count,
};
static struct device_attribute w1_master_attribute_attempts = {
.attr = {
.name = "w1_master_attempts",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_master_attribute_show_attempts,
};
static struct device_attribute w1_master_attribute_max_slave_count = {
.attr = {
.name = "w1_master_max_slave_count",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_master_attribute_show_max_slave_count,
};
static struct device_attribute w1_master_attribute_timeout = {
.attr = {
.name = "w1_master_timeout",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_master_attribute_show_timeout,
};
static struct device_attribute w1_master_attribute_pointer = {
.attr = {
.name = "w1_master_pointer",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_master_attribute_show_pointer,
};
static struct device_attribute w1_master_attribute_name = {
.attr = {
.name = "w1_master_name",
.mode = S_IRUGO,
.owner = THIS_MODULE
},
.show = &w1_master_attribute_show_name,
};
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 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));
memcpy(&sl->attr_val, &w1_slave_attribute_val, sizeof(sl->attr_val));
sl->attr_bin.read = sl->family->fops->rbin;
sl->attr_name.show = sl->family->fops->rname;
sl->attr_val.show = sl->family->fops->rval;
sl->attr_val.attr.name = sl->family->fops->rvalname;
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;
}
err = device_create_file(&sl->dev, &sl->attr_val);
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;
}
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_remove_file(&sl->dev, &sl->attr_val);
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) {
spin_unlock(&w1_flock);
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);
kfree(sl);
return -ENODEV;
}
__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);
}
sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
device_remove_file(&sl->dev, &sl->attr_name);
device_remove_file(&sl->dev, &sl->attr_val);
device_unregister(&sl->dev);
w1_family_put(sl->family);
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_irq(&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_irq(&w1_mlock);
return (found)?dev:NULL;
}
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++;
}
if (slave_count == dev->slave_count && rn ) {
tmp = cpu_to_le64(rn);
if(((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&tmp, 7))
w1_attach_slave_device(dev, (struct w1_reg_num *) &rn);
}
atomic_dec(&dev->refcnt);
}
void w1_search(struct w1_master *dev)
{
u64 last, rn, tmp;
int i, count = 0;
int last_family_desc, last_zero, last_device;
int search_bit, id_bit, comp_bit, desc_bit;
search_bit = id_bit = comp_bit = 0;
rn = tmp = last = 0;
last_device = last_zero = last_family_desc = 0;
desc_bit = 64;
while (!(id_bit && comp_bit) && !last_device
&& count++ < dev->max_slave_count) {
last = rn;
rn = 0;
last_family_desc = 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;
}
#if 1
w1_write_8(dev, W1_SEARCH);
for (i = 0; i < 64; ++i) {
/*
* Read 2 bits from bus.
* All who don't sleep must send ID bit and COMPLEMENT ID bit.
* They actually are ANDed between all senders.
*/
id_bit = w1_touch_bit(dev, 1);
comp_bit = w1_touch_bit(dev, 1);
if (id_bit && comp_bit)
break;
if (id_bit == 0 && comp_bit == 0) {
if (i == desc_bit)
search_bit = 1;
else if (i > desc_bit)
search_bit = 0;
else
search_bit = ((last >> i) & 0x1);
if (search_bit == 0) {
last_zero = i;
if (last_zero < 9)
last_family_desc = last_zero;
}
}
else
search_bit = id_bit;
tmp = search_bit;
rn |= (tmp << i);
/*
* Write 1 bit to bus
* and make all who don't have "search_bit" in "i"'th position
* in it's registration number sleep.
*/
if (dev->bus_master->touch_bit)
w1_touch_bit(dev, search_bit);
else
w1_write_bit(dev, search_bit);
}
#endif
if (desc_bit == last_zero)
last_device = 1;
desc_bit = last_zero;
w1_slave_found(dev->bus_master->data, rn);
}
}
int w1_create_master_attributes(struct w1_master *dev)
{
if ( device_create_file(&dev->dev, &w1_master_attribute_slaves) < 0 ||
device_create_file(&dev->dev, &w1_master_attribute_slave_count) < 0 ||
device_create_file(&dev->dev, &w1_master_attribute_attempts) < 0 ||
device_create_file(&dev->dev, &w1_master_attribute_max_slave_count) < 0 ||
device_create_file(&dev->dev, &w1_master_attribute_timeout) < 0||
device_create_file(&dev->dev, &w1_master_attribute_pointer) < 0||
device_create_file(&dev->dev, &w1_master_attribute_name) < 0)
return -EINVAL;
return 0;
}
void w1_destroy_master_attributes(struct w1_master *dev)
{
device_remove_file(&dev->dev, &w1_master_attribute_slaves);
device_remove_file(&dev->dev, &w1_master_attribute_slave_count);
device_remove_file(&dev->dev, &w1_master_attribute_attempts);
device_remove_file(&dev->dev, &w1_master_attribute_max_slave_count);
device_remove_file(&dev->dev, &w1_master_attribute_timeout);
device_remove_file(&dev->dev, &w1_master_attribute_pointer);
device_remove_file(&dev->dev, &w1_master_attribute_name);
}
int w1_control(void *data)
{
struct w1_slave *sl;
struct w1_master *dev;
struct list_head *ent, *ment, *n, *mn;
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_safe(ment, mn, &w1_masters) {
dev = list_entry(ment, struct w1_master, w1_master_entry);
if (!control_needs_exit && !dev->need_exit)
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;
}
spin_lock(&w1_mlock);
list_del(&dev->w1_master_entry);
spin_unlock(&w1_mlock);
if (control_needs_exit) {
dev->need_exit = 1;
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);
}
wait_for_completion(&dev->dev_exited);
list_for_each_safe(ent, n, &dev->slist) {
sl = list_entry(ent, struct w1_slave, w1_slave_entry);
if (!sl)
dev_warn(&dev->dev,
"%s: slave entry is NULL.\n",
__func__);
else {
list_del(&sl->w1_slave_entry);
w1_slave_detach(sl);
kfree(sl);
}
}
w1_destroy_master_attributes(dev);
atomic_dec(&dev->refcnt);
}
}
complete_and_exit(&w1_control_complete, 0);
}
int w1_process(void *data)
{
struct w1_master *dev = (struct w1_master *) data;
struct list_head *ent, *n;
struct w1_slave *sl;
daemonize("%s", dev->name);
allow_signal(SIGTERM);
while (!dev->need_exit) {
try_to_freeze(PF_FREEZE);
msleep_interruptible(w1_timeout * 1000);
if (signal_pending(current))
flush_signals(current);
if (dev->need_exit)
break;
if (!dev->initialized)
continue;
if (down_interruptible(&dev->mutex))
continue;
list_for_each_safe(ent, n, &dev->slist) {
sl = list_entry(ent, struct w1_slave, w1_slave_entry);
if (sl)
clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
}
w1_search_devices(dev, w1_slave_found);
list_for_each_safe(ent, n, &dev->slist) {
sl = list_entry(ent, struct w1_slave, w1_slave_entry);
if (sl && !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;
}
up(&dev->mutex);
}
atomic_dec(&dev->refcnt);
complete_and_exit(&dev->dev_exited, 0);
return 0;
}
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;
}
void w1_fini(void)
{
struct w1_master *dev;
struct list_head *ent, *n;
list_for_each_safe(ent, n, &w1_masters) {
dev = list_entry(ent, struct w1_master, 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);