[deliverable/linux.git] / drivers / w1 / w1_family.c

/*
 *	w1_family.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/spinlock.h>
#include <linux/list.h>
#include <linux/sched.h>	/* schedule_timeout() */
#include <linux/delay.h>
#include <linux/export.h>

#include "w1_family.h"
#include "w1.h"

DEFINE_SPINLOCK(w1_flock);
static LIST_HEAD(w1_families);

/**
 * w1_register_family() - register a device family driver
 * @newf:	family to register
 */
int w1_register_family(struct w1_family *newf)
{
	struct list_head *ent, *n;
	struct w1_family *f;
	int ret = 0;

	spin_lock(&w1_flock);
	list_for_each_safe(ent, n, &w1_families) {
		f = list_entry(ent, struct w1_family, family_entry);

		if (f->fid == newf->fid) {
			ret = -EEXIST;
			break;
		}
	}

	if (!ret) {
		atomic_set(&newf->refcnt, 0);
		list_add_tail(&newf->family_entry, &w1_families);
	}
	spin_unlock(&w1_flock);

	/* check default devices against the new set of drivers */
	w1_reconnect_slaves(newf, 1);

	return ret;
}

/**
 * w1_unregister_family() - unregister a device family driver
 * @fent:	family to unregister
 */
void w1_unregister_family(struct w1_family *fent)
{
	struct list_head *ent, *n;
	struct w1_family *f;

	spin_lock(&w1_flock);
	list_for_each_safe(ent, n, &w1_families) {
		f = list_entry(ent, struct w1_family, family_entry);

		if (f->fid == fent->fid) {
			list_del(&fent->family_entry);
			break;
		}
	}
	spin_unlock(&w1_flock);

	/* deatch devices using this family code */
	w1_reconnect_slaves(fent, 0);

	while (atomic_read(&fent->refcnt)) {
		printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n",
				fent->fid, atomic_read(&fent->refcnt));

		if (msleep_interruptible(1000))
			flush_signals(current);
	}
}

/*
 * Should be called under w1_flock held.
 */
struct w1_family * w1_family_registered(u8 fid)
{
	struct list_head *ent, *n;
	struct w1_family *f = NULL;
	int ret = 0;

	list_for_each_safe(ent, n, &w1_families) {
		f = list_entry(ent, struct w1_family, family_entry);

		if (f->fid == fid) {
			ret = 1;
			break;
		}
	}

	return (ret) ? f : NULL;
}

static void __w1_family_put(struct w1_family *f)
{
	atomic_dec(&f->refcnt);
}

void w1_family_put(struct w1_family *f)
{
	spin_lock(&w1_flock);
	__w1_family_put(f);
	spin_unlock(&w1_flock);
}

#if 0
void w1_family_get(struct w1_family *f)
{
	spin_lock(&w1_flock);
	__w1_family_get(f);
	spin_unlock(&w1_flock);
}
#endif  /*  0  */

void __w1_family_get(struct w1_family *f)
{
	smp_mb__before_atomic();
	atomic_inc(&f->refcnt);
	smp_mb__after_atomic();
}

EXPORT_SYMBOL(w1_unregister_family);
EXPORT_SYMBOL(w1_register_family);
Commit	Line	Data
1da177e4	1	/*
7785925d	2	* w1_family.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/spinlock.h>
	23	#include <linux/list.h>
4e57b681	24	#include <linux/sched.h> /* schedule_timeout() */
1da177e4	25	#include <linux/delay.h>
9623932c	26	#include <linux/export.h>
1da177e4 LT	27
1da177e4 LT	28	#include "w1_family.h"
a9fb1c7b	29	#include "w1.h"
1da177e4 LT	30
	31	DEFINE_SPINLOCK(w1_flock);
	32	static LIST_HEAD(w1_families);
	33
b3be177a DF	34	/**
	35	* w1_register_family() - register a device family driver
	36	* @newf: family to register
	37	*/
1da177e4 LT	38	int w1_register_family(struct w1_family *newf)
	39	{
	40	struct list_head ent, n;
	41	struct w1_family *f;
	42	int ret = 0;
	43
1da177e4 LT	44	spin_lock(&w1_flock);
	45	list_for_each_safe(ent, n, &w1_families) {
	46	f = list_entry(ent, struct w1_family, family_entry);
	47
	48	if (f->fid == newf->fid) {
	49	ret = -EEXIST;
	50	break;
	51	}
	52	}
	53
	54	if (!ret) {
	55	atomic_set(&newf->refcnt, 0);
1da177e4 LT	56	list_add_tail(&newf->family_entry, &w1_families);
1da177e4 LT	57	}
1da177e4 LT	58	spin_unlock(&w1_flock);
1da177e4 LT	59
c30c9b15 DF	60	/* check default devices against the new set of drivers */
c30c9b15 DF	61	w1_reconnect_slaves(newf, 1);
6adf87bd	62
1da177e4 LT	63	return ret;
	64	}
	65
b3be177a DF	66	/**
	67	* w1_unregister_family() - unregister a device family driver
	68	* @fent: family to unregister
	69	*/
1da177e4 LT	70	void w1_unregister_family(struct w1_family *fent)
	71	{
	72	struct list_head ent, n;
	73	struct w1_family *f;
	74
	75	spin_lock(&w1_flock);
	76	list_for_each_safe(ent, n, &w1_families) {
	77	f = list_entry(ent, struct w1_family, family_entry);
	78
	79	if (f->fid == fent->fid) {
	80	list_del(&fent->family_entry);
	81	break;
	82	}
	83	}
1da177e4 LT	84	spin_unlock(&w1_flock);
1da177e4 LT	85
c30c9b15 DF	86	/* deatch devices using this family code */
	87	w1_reconnect_slaves(fent, 0);
	88
1da177e4 LT	89	while (atomic_read(&fent->refcnt)) {
	90	printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n",
	91	fent->fid, atomic_read(&fent->refcnt));
	92
	93	if (msleep_interruptible(1000))
	94	flush_signals(current);
	95	}
	96	}
	97
	98	/*
	99	* Should be called under w1_flock held.
	100	*/
	101	struct w1_family * w1_family_registered(u8 fid)
	102	{
	103	struct list_head ent, n;
	104	struct w1_family *f = NULL;
	105	int ret = 0;
	106
	107	list_for_each_safe(ent, n, &w1_families) {
	108	f = list_entry(ent, struct w1_family, family_entry);
	109
	110	if (f->fid == fid) {
	111	ret = 1;
	112	break;
	113	}
	114	}
	115
	116	return (ret) ? f : NULL;
	117	}
	118
70d484bf EP	119	static void __w1_family_put(struct w1_family *f)
70d484bf EP	120	{
fe3cb823	121	atomic_dec(&f->refcnt);
70d484bf EP	122	}
70d484bf EP	123
1da177e4 LT	124	void w1_family_put(struct w1_family *f)
	125	{
	126	spin_lock(&w1_flock);
	127	__w1_family_put(f);
	128	spin_unlock(&w1_flock);
	129	}
	130
70d484bf	131	#if 0
1da177e4 LT	132	void w1_family_get(struct w1_family *f)
	133	{
	134	spin_lock(&w1_flock);
	135	__w1_family_get(f);
	136	spin_unlock(&w1_flock);
1da177e4	137	}
70d484bf	138	#endif /* 0 */
1da177e4 LT	139
	140	void __w1_family_get(struct w1_family *f)
	141	{
4e857c58	142	smp_mb__before_atomic();
1da177e4	143	atomic_inc(&f->refcnt);
4e857c58	144	smp_mb__after_atomic();
1da177e4 LT	145	}
1da177e4 LT	146
1da177e4 LT	147	EXPORT_SYMBOL(w1_unregister_family);
1da177e4 LT	148	EXPORT_SYMBOL(w1_register_family);