/* SPDX-License-Identifier: GPL-2.0 */
/*
 * DMA BUF PagePool implementation
 * Based on earlier ION code by Google
 *
 * Copyright (C) 2011 Google, Inc.
 * Copyright (C) 2020 Linaro Ltd.
 * Copyright (C) 2022 Rockchip Electronics Co.Ltd
 */

#ifndef _LINUX_DMABUF_PAGE_POOL_H
#define _LINUX_DMABUF_PAGE_POOL_H

#include <linux/device.h>
#include <linux/kref.h>
#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/shrinker.h>
#include <linux/types.h>

/* page types we track in the pool */
enum {
	POOL_LOWPAGE,      /* Clean lowmem pages */
	POOL_HIGHPAGE,     /* Clean highmem pages */

	POOL_TYPE_SIZE,
};

/**
 * struct dmabuf_page_pool - pagepool struct
 * @count[]:		array of number of pages of that type in the pool
 * @items[]:		array of list of pages of the specific type
 * @mutex:		lock protecting this struct and especially the count
 *			item list
 * @gfp_mask:		gfp_mask to use from alloc
 * @order:		order of pages in the pool
 * @list:		list node for list of pools
 *
 * Allows you to keep a pool of pre allocated pages to use
 */
struct dmabuf_page_pool {
	int count[POOL_TYPE_SIZE];
	struct list_head items[POOL_TYPE_SIZE];
	struct mutex mutex;
	gfp_t gfp_mask;
	unsigned int order;
	struct list_head list;
};

#ifdef CONFIG_DMABUF_PAGE_POOL
struct dmabuf_page_pool *dmabuf_page_pool_create(gfp_t gfp_mask,
						 unsigned int order);
void dmabuf_page_pool_destroy(struct dmabuf_page_pool *pool);
struct page *dmabuf_page_pool_alloc(struct dmabuf_page_pool *pool);
void dmabuf_page_pool_free(struct dmabuf_page_pool *pool, struct page *page);

struct page **
dmabuf_page_pool_alloc_pages_array(struct dmabuf_page_pool *pool, int npages);

void dmabuf_page_pool_free_pages_array(struct dmabuf_page_pool *pool,
				       struct page **pages, int npages);
#else
static inline struct dmabuf_page_pool *
dmabuf_page_pool_create(gfp_t gfp_mask, unsigned int order)
{
	return NULL;
}

static inline void dmabuf_page_pool_destroy(struct dmabuf_page_pool *pool) { }

static inline struct page *
dmabuf_page_pool_alloc(struct dmabuf_page_pool *pool)
{
	return NULL;
}

static inline void
dmabuf_page_pool_free(struct dmabuf_page_pool *pool, struct page *page) { }

static inline struct page **
dmabuf_page_pool_alloc_pages_array(struct dmabuf_page_pool *pool, int npages)
{
	return NULL;
}

static inline void
dmabuf_page_pool_free_pages_array(struct dmabuf_page_pool *pool, struct page **pages,
		       int npages) { }

#endif

#endif