[mirror_ubuntu-artful-kernel.git] / drivers / w1 / w1_int.c

/*
 *	w1_int.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/kernel.h>
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/moduleparam.h>

#include "w1.h"
#include "w1_log.h"
#include "w1_netlink.h"
#include "w1_int.h"

static int w1_search_count = -1; /* Default is continual scan */
module_param_named(search_count, w1_search_count, int, 0);

static int w1_enable_pullup = 1;
module_param_named(enable_pullup, w1_enable_pullup, int, 0);

static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
				       struct device_driver *driver,
				       struct device *device)
{
	struct w1_master *dev;
	int err;

	/*
	 * We are in process context(kernel thread), so can sleep.
	 */
	dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
	if (!dev) {
		pr_err("Failed to allocate %zd bytes for new w1 device.\n",
			sizeof(struct w1_master));
		return NULL;
	}


	dev->bus_master = (struct w1_bus_master *)(dev + 1);

	dev->owner		= THIS_MODULE;
	dev->max_slave_count	= slave_count;
	dev->slave_count	= 0;
	dev->attempts		= 0;
	dev->initialized	= 0;
	dev->id			= id;
	dev->slave_ttl		= slave_ttl;
	dev->search_count	= w1_search_count;
	dev->enable_pullup	= w1_enable_pullup;

	/* 1 for w1_process to decrement
	 * 1 for __w1_remove_master_device to decrement
	 */
	atomic_set(&dev->refcnt, 2);

	INIT_LIST_HEAD(&dev->slist);
	INIT_LIST_HEAD(&dev->async_list);
	mutex_init(&dev->mutex);
	mutex_init(&dev->bus_mutex);
	mutex_init(&dev->list_mutex);

	memcpy(&dev->dev, device, sizeof(struct device));
	dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
	snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
	dev->dev.init_name = dev->name;

	dev->driver = driver;

	dev->seq = 1;

	err = device_register(&dev->dev);
	if (err) {
		pr_err("Failed to register master device. err=%d\n", err);
		memset(dev, 0, sizeof(struct w1_master));
		kfree(dev);
		dev = NULL;
	}

	return dev;
}

static void w1_free_dev(struct w1_master *dev)
{
	device_unregister(&dev->dev);
}

/**
 * w1_add_master_device() - registers a new master device
 * @master:	master bus device to register
 */
int w1_add_master_device(struct w1_bus_master *master)
{
	struct w1_master *dev, *entry;
	int retval = 0;
	struct w1_netlink_msg msg;
	int id, found;

	/* validate minimum functionality */
	if (!(master->touch_bit && master->reset_bus) &&
	    !(master->write_bit && master->read_bit) &&
	    !(master->write_byte && master->read_byte && master->reset_bus)) {
		pr_err("w1_add_master_device: invalid function set\n");
		return(-EINVAL);
	}

	/* Lock until the device is added (or not) to w1_masters. */
	mutex_lock(&w1_mlock);
	/* Search for the first available id (starting at 1). */
	id = 0;
	do {
		++id;
		found = 0;
		list_for_each_entry(entry, &w1_masters, w1_master_entry) {
			if (entry->id == id) {
				found = 1;
				break;
			}
		}
	} while (found);

	dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
		&w1_master_driver, &w1_master_device);
	if (!dev) {
		mutex_unlock(&w1_mlock);
		return -ENOMEM;
	}

	retval =  w1_create_master_attributes(dev);
	if (retval) {
		mutex_unlock(&w1_mlock);
		goto err_out_free_dev;
	}

	memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));

	dev->initialized = 1;

	dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
	if (IS_ERR(dev->thread)) {
		retval = PTR_ERR(dev->thread);
		dev_err(&dev->dev,
			 "Failed to create new kernel thread. err=%d\n",
			 retval);
		mutex_unlock(&w1_mlock);
		goto err_out_rm_attr;
	}

	list_add(&dev->w1_master_entry, &w1_masters);
	mutex_unlock(&w1_mlock);

	memset(&msg, 0, sizeof(msg));
	msg.id.mst.id = dev->id;
	msg.type = W1_MASTER_ADD;
	w1_netlink_send(dev, &msg);

	return 0;

#if 0 /* Thread cleanup code, not required currently. */
err_out_kill_thread:
	set_bit(W1_ABORT_SEARCH, &dev->flags);
	kthread_stop(dev->thread);
#endif
err_out_rm_attr:
	w1_destroy_master_attributes(dev);
err_out_free_dev:
	w1_free_dev(dev);

	return retval;
}

void __w1_remove_master_device(struct w1_master *dev)
{
	struct w1_netlink_msg msg;
	struct w1_slave *sl, *sln;

	mutex_lock(&w1_mlock);
	list_del(&dev->w1_master_entry);
	mutex_unlock(&w1_mlock);

	set_bit(W1_ABORT_SEARCH, &dev->flags);
	kthread_stop(dev->thread);

	mutex_lock(&dev->mutex);
	mutex_lock(&dev->list_mutex);
	list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
		mutex_unlock(&dev->list_mutex);
		w1_slave_detach(sl);
		mutex_lock(&dev->list_mutex);
	}
	w1_destroy_master_attributes(dev);
	mutex_unlock(&dev->list_mutex);
	mutex_unlock(&dev->mutex);
	atomic_dec(&dev->refcnt);

	while (atomic_read(&dev->refcnt)) {
		dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
				dev->name, atomic_read(&dev->refcnt));

		if (msleep_interruptible(1000))
			flush_signals(current);
		mutex_lock(&dev->list_mutex);
		w1_process_callbacks(dev);
		mutex_unlock(&dev->list_mutex);
	}
	mutex_lock(&dev->list_mutex);
	w1_process_callbacks(dev);
	mutex_unlock(&dev->list_mutex);

	memset(&msg, 0, sizeof(msg));
	msg.id.mst.id = dev->id;
	msg.type = W1_MASTER_REMOVE;
	w1_netlink_send(dev, &msg);

	w1_free_dev(dev);
}

/**
 * w1_remove_master_device() - unregister a master device
 * @bm:	master bus device to remove
 */
void w1_remove_master_device(struct w1_bus_master *bm)
{
	struct w1_master *dev, *found = NULL;

	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
		if (!dev->initialized)
			continue;

		if (dev->bus_master->data == bm->data) {
			found = dev;
			break;
		}
	}

	if (!found) {
		pr_err("Device doesn't exist.\n");
		return;
	}

	__w1_remove_master_device(found);
}

EXPORT_SYMBOL(w1_add_master_device);
EXPORT_SYMBOL(w1_remove_master_device);
Commit	Line	Data
1da177e4	1	/*
7785925d	2	* w1_int.c
1da177e4	3	*
a8018766	4	* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
7785925d	5	*
1da177e4 LT	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	#include <linux/kernel.h>
	23	#include <linux/list.h>
	24	#include <linux/delay.h>
674a396c	25	#include <linux/kthread.h>
5a0e3ad6	26	#include <linux/slab.h>
9623932c	27	#include <linux/export.h>
4d184129	28	#include <linux/moduleparam.h>
1da177e4 LT	29
	30	#include "w1.h"
	31	#include "w1_log.h"
	32	#include "w1_netlink.h"
70d484bf	33	#include "w1_int.h"
1da177e4	34
9141f57c DF	35	static int w1_search_count = -1; /* Default is continual scan */
9141f57c DF	36	module_param_named(search_count, w1_search_count, int, 0);
1da177e4	37
6a158c0d DF	38	static int w1_enable_pullup = 1;
	39	module_param_named(enable_pullup, w1_enable_pullup, int, 0);
	40
7242d42a	41	static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
7785925d EP	42	struct device_driver *driver,
7785925d EP	43	struct device *device)
1da177e4 LT	44	{
	45	struct w1_master *dev;
	46	int err;
	47
	48	/*
	49	* We are in process context(kernel thread), so can sleep.
	50	*/
dd00cc48	51	dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
1da177e4	52	if (!dev) {
fdc9167a	53	pr_err("Failed to allocate %zd bytes for new w1 device.\n",
1da177e4 LT	54	sizeof(struct w1_master));
	55	return NULL;
	56	}
	57
1da177e4 LT	58
	59	dev->bus_master = (struct w1_bus_master *)(dev + 1);
	60
7785925d EP	61	dev->owner = THIS_MODULE;
	62	dev->max_slave_count = slave_count;
	63	dev->slave_count = 0;
	64	dev->attempts = 0;
7785925d EP	65	dev->initialized = 0;
7785925d EP	66	dev->id = id;
1da177e4	67	dev->slave_ttl = slave_ttl;
9141f57c	68	dev->search_count = w1_search_count;
6a158c0d	69	dev->enable_pullup = w1_enable_pullup;
1da177e4	70
01e14d6d DF	71	/* 1 for w1_process to decrement
	72	* 1 for __w1_remove_master_device to decrement
	73	*/
1da177e4 LT	74	atomic_set(&dev->refcnt, 2);
	75
	76	INIT_LIST_HEAD(&dev->slist);
9fcbbac5	77	INIT_LIST_HEAD(&dev->async_list);
abd52a13	78	mutex_init(&dev->mutex);
b02f8bed	79	mutex_init(&dev->bus_mutex);
9fcbbac5	80	mutex_init(&dev->list_mutex);
1da177e4	81
1da177e4	82	memcpy(&dev->dev, device, sizeof(struct device));
40f91de6	83	dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
1da177e4	84	snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
68a436ae	85	dev->dev.init_name = dev->name;
1da177e4 LT	86
	87	dev->driver = driver;
	88
1da177e4	89	dev->seq = 1;
1da177e4 LT	90
	91	err = device_register(&dev->dev);
	92	if (err) {
fdc9167a	93	pr_err("Failed to register master device. err=%d\n", err);
1da177e4 LT	94	memset(dev, 0, sizeof(struct w1_master));
	95	kfree(dev);
	96	dev = NULL;
	97	}
	98
	99	return dev;
	100	}
	101
2c5bfdac	102	static void w1_free_dev(struct w1_master *dev)
1da177e4 LT	103	{
1da177e4 LT	104	device_unregister(&dev->dev);
1da177e4 LT	105	}
1da177e4 LT	106
b3be177a DF	107	/**
	108	* w1_add_master_device() - registers a new master device
	109	* @master: master bus device to register
	110	*/
1da177e4 LT	111	int w1_add_master_device(struct w1_bus_master *master)
1da177e4 LT	112	{
af00a2d5	113	struct w1_master dev, entry;
1da177e4 LT	114	int retval = 0;
1da177e4 LT	115	struct w1_netlink_msg msg;
af00a2d5	116	int id, found;
1da177e4	117
7242d42a TW	118	/* validate minimum functionality */
	119	if (!(master->touch_bit && master->reset_bus) &&
	120	!(master->write_bit && master->read_bit) &&
c1f858b7	121	!(master->write_byte && master->read_byte && master->reset_bus)) {
fdc9167a	122	pr_err("w1_add_master_device: invalid function set\n");
6adf87bd	123	return(-EINVAL);
7242d42a	124	}
be57ce26	125
af00a2d5 DF	126	/* Lock until the device is added (or not) to w1_masters. */
	127	mutex_lock(&w1_mlock);
	128	/* Search for the first available id (starting at 1). */
	129	id = 0;
	130	do {
	131	++id;
	132	found = 0;
	133	list_for_each_entry(entry, &w1_masters, w1_master_entry) {
	134	if (entry->id == id) {
	135	found = 1;
	136	break;
	137	}
	138	}
	139	} while (found);
	140
	141	dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
	142	&w1_master_driver, &w1_master_device);
	143	if (!dev) {
	144	mutex_unlock(&w1_mlock);
1da177e4	145	return -ENOMEM;
af00a2d5	146	}
1da177e4	147
01e14d6d	148	retval = w1_create_master_attributes(dev);
af00a2d5 DF	149	if (retval) {
af00a2d5 DF	150	mutex_unlock(&w1_mlock);
01e14d6d	151	goto err_out_free_dev;
af00a2d5	152	}
01e14d6d DF	153
	154	memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
	155
	156	dev->initialized = 1;
	157
674a396c EP	158	dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
	159	if (IS_ERR(dev->thread)) {
	160	retval = PTR_ERR(dev->thread);
1da177e4 LT	161	dev_err(&dev->dev,
1da177e4 LT	162	"Failed to create new kernel thread. err=%d\n",
674a396c	163	retval);
af00a2d5	164	mutex_unlock(&w1_mlock);
01e14d6d	165	goto err_out_rm_attr;
1da177e4 LT	166	}
1da177e4 LT	167
1da177e4	168	list_add(&dev->w1_master_entry, &w1_masters);
abd52a13	169	mutex_unlock(&w1_mlock);
1da177e4	170
12003375	171	memset(&msg, 0, sizeof(msg));
1da177e4	172	msg.id.mst.id = dev->id;
1da177e4 LT	173	msg.type = W1_MASTER_ADD;
	174	w1_netlink_send(dev, &msg);
	175
	176	return 0;
	177
01e14d6d	178	#if 0 /* Thread cleanup code, not required currently. */
1da177e4	179	err_out_kill_thread:
42105698	180	set_bit(W1_ABORT_SEARCH, &dev->flags);
674a396c	181	kthread_stop(dev->thread);
01e14d6d DF	182	#endif
	183	err_out_rm_attr:
	184	w1_destroy_master_attributes(dev);
1da177e4 LT	185	err_out_free_dev:
	186	w1_free_dev(dev);
	187
	188	return retval;
	189	}
	190
	191	void __w1_remove_master_device(struct w1_master *dev)
	192	{
1da177e4	193	struct w1_netlink_msg msg;
c30c9b15	194	struct w1_slave sl, sln;
1da177e4	195
c30c9b15 DF	196	mutex_lock(&w1_mlock);
	197	list_del(&dev->w1_master_entry);
	198	mutex_unlock(&w1_mlock);
	199
9fcbbac5 DF	200	set_bit(W1_ABORT_SEARCH, &dev->flags);
	201	kthread_stop(dev->thread);
	202
c30c9b15	203	mutex_lock(&dev->mutex);
9fcbbac5 DF	204	mutex_lock(&dev->list_mutex);
	205	list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
	206	mutex_unlock(&dev->list_mutex);
c30c9b15	207	w1_slave_detach(sl);
9fcbbac5 DF	208	mutex_lock(&dev->list_mutex);
9fcbbac5 DF	209	}
c30c9b15	210	w1_destroy_master_attributes(dev);
9fcbbac5	211	mutex_unlock(&dev->list_mutex);
c30c9b15 DF	212	mutex_unlock(&dev->mutex);
	213	atomic_dec(&dev->refcnt);
	214
1da177e4	215	while (atomic_read(&dev->refcnt)) {
674a396c	216	dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
1da177e4 LT	217	dev->name, atomic_read(&dev->refcnt));
	218
	219	if (msleep_interruptible(1000))
	220	flush_signals(current);
a0f10464	221	mutex_lock(&dev->list_mutex);
9fcbbac5	222	w1_process_callbacks(dev);
a0f10464	223	mutex_unlock(&dev->list_mutex);
1da177e4	224	}
a0f10464	225	mutex_lock(&dev->list_mutex);
9fcbbac5	226	w1_process_callbacks(dev);
a0f10464	227	mutex_unlock(&dev->list_mutex);
1da177e4	228
12003375	229	memset(&msg, 0, sizeof(msg));
1da177e4	230	msg.id.mst.id = dev->id;
1da177e4 LT	231	msg.type = W1_MASTER_REMOVE;
	232	w1_netlink_send(dev, &msg);
	233
	234	w1_free_dev(dev);
	235	}
	236
b3be177a DF	237	/**
	238	* w1_remove_master_device() - unregister a master device
	239	* @bm: master bus device to remove
	240	*/
1da177e4 LT	241	void w1_remove_master_device(struct w1_bus_master *bm)
1da177e4 LT	242	{
59d9445e	243	struct w1_master dev, found = NULL;
1da177e4	244
7785925d	245	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
1da177e4 LT	246	if (!dev->initialized)
	247	continue;
	248
59d9445e EP	249	if (dev->bus_master->data == bm->data) {
59d9445e EP	250	found = dev;
1da177e4	251	break;
59d9445e	252	}
1da177e4 LT	253	}
1da177e4 LT	254
59d9445e	255	if (!found) {
fdc9167a	256	pr_err("Device doesn't exist.\n");
1da177e4 LT	257	return;
	258	}
	259
59d9445e	260	__w1_remove_master_device(found);
1da177e4 LT	261	}
	262
	263	EXPORT_SYMBOL(w1_add_master_device);
	264	EXPORT_SYMBOL(w1_remove_master_device);