android_kernel_xiaomi_sm8350/drivers/w1/w1.c
Christoph Lameter 3e1d1d28d9 [PATCH] Cleanup patch for process freezing
1. Establish a simple API for process freezing defined in linux/include/sched.h:

   frozen(process)		Check for frozen process
   freezing(process)		Check if a process is being frozen
   freeze(process)		Tell a process to freeze (go to refrigerator)
   thaw_process(process)	Restart process
   frozen_process(process)	Process is frozen now

2. Remove all references to PF_FREEZE and PF_FROZEN from all
   kernel sources except sched.h

3. Fix numerous locations where try_to_freeze is manually done by a driver

4. Remove the argument that is no longer necessary from two function calls.

5. Some whitespace cleanup

6. Clear potential race in refrigerator (provides an open window of PF_FREEZE
   cleared before setting PF_FROZEN, recalc_sigpending does not check
   PF_FROZEN).

This patch does not address the problem of freeze_processes() violating the rule
that a task may only modify its own flags by setting PF_FREEZE. This is not clean
in an SMP environment. freeze(process) is therefore not SMP safe!

Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 17:10:13 -07:00

831 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();
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();
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);