[linux-2.6-block.git] / drivers / w1 / 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.
 */

#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sched/signal.h>
#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)) {
		pr_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	/*
a8018766	2	* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
7785925d	3	*
1da177e4 LT	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
1da177e4 LT	13	*/
	14
	15	#include <linux/spinlock.h>
	16	#include <linux/list.h>
3f07c014	17	#include <linux/sched/signal.h>
1da177e4	18	#include <linux/delay.h>
9623932c	19	#include <linux/export.h>
1da177e4 LT	20
1da177e4 LT	21	#include "w1_family.h"
a9fb1c7b	22	#include "w1.h"
1da177e4 LT	23
	24	DEFINE_SPINLOCK(w1_flock);
	25	static LIST_HEAD(w1_families);
	26
b3be177a DF	27	/**
	28	* w1_register_family() - register a device family driver
	29	* @newf: family to register
	30	*/
1da177e4 LT	31	int w1_register_family(struct w1_family *newf)
	32	{
	33	struct list_head ent, n;
	34	struct w1_family *f;
	35	int ret = 0;
	36
1da177e4 LT	37	spin_lock(&w1_flock);
	38	list_for_each_safe(ent, n, &w1_families) {
	39	f = list_entry(ent, struct w1_family, family_entry);
	40
	41	if (f->fid == newf->fid) {
	42	ret = -EEXIST;
	43	break;
	44	}
	45	}
	46
	47	if (!ret) {
	48	atomic_set(&newf->refcnt, 0);
1da177e4 LT	49	list_add_tail(&newf->family_entry, &w1_families);
1da177e4 LT	50	}
1da177e4 LT	51	spin_unlock(&w1_flock);
1da177e4 LT	52
c30c9b15 DF	53	/* check default devices against the new set of drivers */
c30c9b15 DF	54	w1_reconnect_slaves(newf, 1);
6adf87bd	55
1da177e4 LT	56	return ret;
	57	}
	58
b3be177a DF	59	/**
	60	* w1_unregister_family() - unregister a device family driver
	61	* @fent: family to unregister
	62	*/
1da177e4 LT	63	void w1_unregister_family(struct w1_family *fent)
	64	{
	65	struct list_head ent, n;
	66	struct w1_family *f;
	67
	68	spin_lock(&w1_flock);
	69	list_for_each_safe(ent, n, &w1_families) {
	70	f = list_entry(ent, struct w1_family, family_entry);
	71
	72	if (f->fid == fent->fid) {
	73	list_del(&fent->family_entry);
	74	break;
	75	}
	76	}
1da177e4 LT	77	spin_unlock(&w1_flock);
1da177e4 LT	78
c30c9b15 DF	79	/* deatch devices using this family code */
	80	w1_reconnect_slaves(fent, 0);
	81
1da177e4	82	while (atomic_read(&fent->refcnt)) {
fdc9167a	83	pr_info("Waiting for family %u to become free: refcnt=%d.\n",
1da177e4 LT	84	fent->fid, atomic_read(&fent->refcnt));
	85
	86	if (msleep_interruptible(1000))
	87	flush_signals(current);
	88	}
	89	}
	90
	91	/*
	92	* Should be called under w1_flock held.
	93	*/
	94	struct w1_family * w1_family_registered(u8 fid)
	95	{
	96	struct list_head ent, n;
	97	struct w1_family *f = NULL;
	98	int ret = 0;
	99
	100	list_for_each_safe(ent, n, &w1_families) {
	101	f = list_entry(ent, struct w1_family, family_entry);
	102
	103	if (f->fid == fid) {
	104	ret = 1;
	105	break;
	106	}
	107	}
	108
	109	return (ret) ? f : NULL;
	110	}
	111
70d484bf EP	112	static void __w1_family_put(struct w1_family *f)
70d484bf EP	113	{
fe3cb823	114	atomic_dec(&f->refcnt);
70d484bf EP	115	}
70d484bf EP	116
1da177e4 LT	117	void w1_family_put(struct w1_family *f)
	118	{
	119	spin_lock(&w1_flock);
	120	__w1_family_put(f);
	121	spin_unlock(&w1_flock);
	122	}
	123
70d484bf	124	#if 0
1da177e4 LT	125	void w1_family_get(struct w1_family *f)
	126	{
	127	spin_lock(&w1_flock);
	128	__w1_family_get(f);
	129	spin_unlock(&w1_flock);
1da177e4	130	}
70d484bf	131	#endif /* 0 */
1da177e4 LT	132
	133	void __w1_family_get(struct w1_family *f)
	134	{
4e857c58	135	smp_mb__before_atomic();
1da177e4	136	atomic_inc(&f->refcnt);
4e857c58	137	smp_mb__after_atomic();
1da177e4 LT	138	}
1da177e4 LT	139
1da177e4 LT	140	EXPORT_SYMBOL(w1_unregister_family);
1da177e4 LT	141	EXPORT_SYMBOL(w1_register_family);