/*
 * Copyright (c) 2012-2013, NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
 */

#ifndef _LINUX_EDP_H
#define _LINUX_EDP_H

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/workqueue.h>
#include <linux/sysfs.h>

#define EDP_NAME_LEN	16
#define EDP_MIN_PRIO	19
#define EDP_MAX_PRIO	0

struct edp_manager {
	char name[EDP_NAME_LEN];
	unsigned int max;

	/* internal */
	struct list_head link;
	struct list_head clients;
	bool registered;
	unsigned int remaining;
	struct edp_governor *gov;
	struct work_struct work;
	unsigned int num_denied;
	struct kobject *kobj;

	/* governor internal */
	void *gov_data;

#ifdef CONFIG_DEBUG_FS
	/* public */
	struct dentry *dentry;
#endif
};

/*
 * @states: EDP state array holding the IMAX for each state.
 *	This must be sorted in descending order.
 * @num_states: length of the above array
 * @e0_index: index of the E0 state in the above array
 * @max_borrowers: maximum number of clients allowed to borrow from this
 * @priority: client priority - should be between EDP_MIN_PRIO & EDP_MAX_PRIO
 * @throttle: throttle callback function
 * @notify_loan_update: for receiving loan size change notifications
 *	(clients should return the amount of loan consumed)
 * @notify_loan_close: for receiving loan closure notification
 * Note that each EDP client is tied to a single EDP manager
 */
struct edp_client {
	char name[EDP_NAME_LEN];
	unsigned int *states;
	unsigned int num_states;
	unsigned int e0_index;
	unsigned int max_borrowers;
	int priority;
	void *private_data;
	struct edp_client_attribute *attrs;
	unsigned int notify_ui;

	void (*throttle)(unsigned int new_state, void *priv_data);
	void (*notify_promotion)(unsigned int new_state, void *priv_data);
	unsigned int (*notify_loan_update)(unsigned int new_size,
			struct edp_client *lender, void *priv_data);
	void (*notify_loan_close)(struct edp_client *lender, void *priv_data);

	/* internal */
	struct list_head link;
	struct list_head borrowers;
	struct edp_manager *manager;
	const unsigned int *req;
	const unsigned int *cur;
	unsigned int ithreshold;
	unsigned int num_borrowers;
	unsigned int num_loans;
	struct kobject *kobj;

	/* governor internal */
	unsigned int gwt;
	struct list_head glnk;

#ifdef CONFIG_DEBUG_FS
	/* public */
	struct dentry *dentry;
#endif
};

struct edp_client_attribute {
	struct attribute attr;
	ssize_t (*show)(struct edp_client *c,
			struct edp_client_attribute *attr, char *buf);
	ssize_t (*store)(struct edp_client *c,
			struct edp_client_attribute *attr,
			const char *buf, size_t count);
};

struct edp_governor {
	char name[EDP_NAME_LEN];
	struct module *owner;

	int (*start)(struct edp_manager *mgr);
	void (*stop)(struct edp_manager *mgr);
	void (*update_request)(struct edp_client *client,
			const unsigned int *req);
	void (*update_loans)(struct edp_client *client);
	void (*promote)(struct edp_manager *mgr);

	/* internal */
	struct list_head link;
	unsigned int refcnt;
};

static inline int edp_register_manager(struct edp_manager *mgr)
{ return -ENODEV; }
static inline int edp_unregister_manager(struct edp_manager *mgr)
{ return -ENODEV; }
static inline struct edp_manager *edp_get_manager(const char *name)
{ return NULL; }
static inline int edp_register_client(struct edp_manager *mgr,
		struct edp_client *client)
{ return -ENODEV; }
static inline int edp_unregister_client(struct edp_client *client)
{ return -ENODEV; }
static inline int edp_update_client_request(struct edp_client *client,
		unsigned int req, unsigned int *approved)
{ return -ENODEV; }
static inline struct edp_client *edp_get_client(const char *name)
{ return NULL; }
static inline int edp_register_loan(struct edp_client *lender,
		struct edp_client *borrower)
{ return -ENODEV; }
static inline int edp_unregister_loan(struct edp_client *lender,
		struct edp_client *borrower)
{ return -ENODEV; }
static inline int edp_update_loan_threshold(struct edp_client *lender,
		unsigned int threshold)
{ return -ENODEV; }
static inline int edp_register_governor(struct edp_governor *gov)
{ return -ENODEV; }
static inline int edp_unregister_governor(struct edp_governor *gov)
{ return -ENODEV; }
static inline struct edp_governor *edp_get_governor(const char *name)
{ return NULL; }
static inline int edp_set_governor(struct edp_manager *mgr,
		struct edp_governor *gov)
{ return -ENODEV; }

#endif