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/* -*- mode: c; c-basic-offset: 8; -*-

 * vim: noexpandtab sw=8 ts=8 sts=0:

 *

 * configfs.h - definitions for the device driver filesystem

 *

 * 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 021110-1307, USA.

 *

 * Based on sysfs:

 *      sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel

 *

 * Based on kobject.h:

 *      Copyright (c) 2002-2003 Patrick Mochel

 *      Copyright (c) 2002-2003 Open Source Development Labs

 *

 * configfs Copyright (C) 2005 Oracle.  All rights reserved.

 *

 * Please read Documentation/filesystems/configfs.txt before using the

 * configfs interface, ESPECIALLY the parts about reference counts and

 * item destructors.

 */

#ifndef _CONFIGFS_H_

#define _CONFIGFS_H_

#ifdef __KERNEL__

#include <linux/types.h>

#include <linux/list.h>

#include <linux/kref.h>

#include <linux/mutex.h>

#include <asm/atomic.h>

#define CONFIGFS_ITEM_NAME_LEN  20

struct module;

struct configfs_item_operations;

struct configfs_group_operations;

struct configfs_attribute;

struct configfs_subsystem;

struct config_item {

        char                    *ci_name;

        char                    ci_namebuf[CONFIGFS_ITEM_NAME_LEN];

        struct kref             ci_kref;

        struct list_head        ci_entry;

        struct config_item      *ci_parent;

        struct config_group     *ci_group;

        struct config_item_type *ci_type;

        struct dentry           *ci_dentry;

};

extern int config_item_set_name(struct config_item *, const char *, ...);

static inline char *config_item_name(struct config_item * item)

{

        return item->ci_name;

}

extern void config_item_init(struct config_item *);

extern void config_item_init_type_name(struct config_item *item,

                                       const char *name,

                                       struct config_item_type *type);

extern struct config_item * config_item_get(struct config_item *);

extern void config_item_put(struct config_item *);

struct config_item_type {

        struct module                           *ct_owner;

        struct configfs_item_operations         *ct_item_ops;

        struct configfs_group_operations        *ct_group_ops;

        struct configfs_attribute               **ct_attrs;

};

/**

 *      group - a group of config_items of a specific type, belonging

 *      to a specific subsystem.

 */

struct config_group {

        struct config_item              cg_item;

        struct list_head                cg_children;

        struct configfs_subsystem       *cg_subsys;

        struct config_group             **default_groups;

};

extern void config_group_init(struct config_group *group);

extern void config_group_init_type_name(struct config_group *group,

                                        const char *name,

                                        struct config_item_type *type);

static inline struct config_group *to_config_group(struct config_item *item)

{

        return item ? container_of(item,struct config_group,cg_item) : NULL;

}

static inline struct config_group *config_group_get(struct config_group *group)

{

        return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;

}

static inline void config_group_put(struct config_group *group)

{

        config_item_put(&group->cg_item);

}

extern struct config_item *config_group_find_item(struct config_group *,

                                                  const char *);

struct configfs_attribute {

        const char              *ca_name;

        struct module           *ca_owner;

        mode_t                  ca_mode;

};

/*

 * Users often need to create attribute structures for their configurable

 * attributes, containing a configfs_attribute member and function pointers

 * for the show() and store() operations on that attribute. They can use

 * this macro (similar to sysfs' __ATTR) to make defining attributes easier.

 */

#define __CONFIGFS_ATTR(_name, _mode, _show, _store)                    \

{                                                                       \

        .attr   = {                                                     \

                        .ca_name = __stringify(_name),                  \

                        .ca_mode = _mode,                               \

                        .ca_owner = THIS_MODULE,                        \

        },                                                              \

        .show   = _show,                                                \

        .store  = _store,                                               \

}

/*

 * If allow_link() exists, the item can symlink(2) out to other

 * items.  If the item is a group, it may support mkdir(2).

 * Groups supply one of make_group() and make_item().  If the

 * group supports make_group(), one can create group children.  If it

 * supports make_item(), one can create config_item children.  If it has

 * default_groups on group->default_groups, it has automatically created

 * group children.  default_groups may coexist alongsize make_group() or

 * make_item(), but if the group wishes to have only default_groups

 * children (disallowing mkdir(2)), it need not provide either function.

 * If the group has commit(), it supports pending and commited (active)

 * items.

 */

struct configfs_item_operations {

        void (*release)(struct config_item *);

        ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *);

        ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);

        int (*allow_link)(struct config_item *src, struct config_item *target);

        int (*drop_link)(struct config_item *src, struct config_item *target);

};

struct configfs_group_operations {

        struct config_item *(*make_item)(struct config_group *group, const char *name);

        struct config_group *(*make_group)(struct config_group *group, const char *name);

        int (*commit_item)(struct config_item *item);

        void (*disconnect_notify)(struct config_group *group, struct config_item *item);

        void (*drop_item)(struct config_group *group, struct config_item *item);

};

struct configfs_subsystem {

        struct config_group     su_group;

        struct mutex            su_mutex;

};

static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)

{

        return group ?

                container_of(group, struct configfs_subsystem, su_group) :

                NULL;

}

int configfs_register_subsystem(struct configfs_subsystem *subsys);

void configfs_unregister_subsystem(struct configfs_subsystem *subsys);

/* These functions can sleep and can alloc with GFP_KERNEL */

/* WARNING: These cannot be called underneath configfs callbacks!! */

int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);

void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);

#endif  /* __KERNEL__ */

#endif /* _CONFIGFS_H_ */