/*
 * drivers/staging/android/ion/ion.h
 *
 * Copyright (C) 2011 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#ifndef _ION_H
#define _ION_H

#include <linux/device.h>
#include <linux/dma-direction.h>
#include <linux/kref.h>
#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
#include <linux/shrinker.h>
#include <linux/types.h>
#include <linux/miscdevice.h>

#include "../uapi/ion.h"

/**
 * struct ion_platform_heap - defines a heap in the given platform
 * @type:       type of the heap from ion_heap_type enum
 * @id:         unique identifier for heap.  When allocating higher numb ers
 *              will be allocated from first.  At allocation these are passed
 *              as a bit mask and therefore can not exceed ION_NUM_HEAP_IDS.
 * @name:       used for debug purposes
 * @base:       base address of heap in physical memory if applicable
 * @size:       size of the heap in bytes if applicable
 * @priv:       private info passed from the board file
 *
 * Provided by the board file.
 */
struct ion_platform_heap {
        enum ion_heap_type type;
        unsigned int id;
        const char *name;
        phys_addr_t base;
        size_t size;
        phys_addr_t align;
        void *priv;
};

/**
 * struct ion_buffer - metadata for a particular buffer
 * @ref:                reference count
 * @node:               node in the ion_device buffers tree
 * @dev:                back pointer to the ion_device
 * @heap:               back pointer to the heap the buffer came from
 * @flags:              buffer specific flags
 * @private_flags:      internal buffer specific flags
 * @size:               size of the buffer
 * @priv_virt:          private data to the buffer representable as
 *                      a void *
 * @lock:               protects the buffers cnt fields
 * @kmap_cnt:           number of times the buffer is mapped to the kernel
 * @vaddr:              the kernel mapping if kmap_cnt is not zero
 * @sg_table:           the sg table for the buffer if dmap_cnt is not zero
 */
struct ion_buffer {
        union {
                struct rb_node node;
                struct list_head list;
        };
        struct ion_device *dev;
        struct ion_heap *heap;
        unsigned long flags;
        unsigned long private_flags;
        size_t size;
        void *priv_virt;
        struct mutex lock;
        int kmap_cnt;
        void *vaddr;
        struct sg_table *sg_table;
        struct list_head attachments;
};
void ion_buffer_destroy(struct ion_buffer *buffer);

/**
 * struct ion_device - the metadata of the ion device node
 * @dev:                the actual misc device
 * @buffers:            an rb tree of all the existing buffers
 * @buffer_lock:        lock protecting the tree of buffers
 * @lock:               rwsem protecting the tree of heaps and clients
 */
struct ion_device {
        struct miscdevice dev;
        struct rb_root buffers;
        struct mutex buffer_lock;
        struct rw_semaphore lock;
        struct plist_head heaps;
        struct dentry *debug_root;
        int heap_cnt;
};

/**
 * struct ion_heap_ops - ops to operate on a given heap
 * @allocate:           allocate memory
 * @free:               free memory
 * @map_kernel          map memory to the kernel
 * @unmap_kernel        unmap memory to the kernel
 * @map_user            map memory to userspace
 *
 * allocate, phys, and map_user return 0 on success, -errno on error.
 * map_dma and map_kernel return pointer on success, ERR_PTR on
 * error. @free will be called with ION_PRIV_FLAG_SHRINKER_FREE set in
 * the buffer's private_flags when called from a shrinker. In that
 * case, the pages being free'd must be truly free'd back to the
 * system, not put in a page pool or otherwise cached.
 */
struct ion_heap_ops {
        int (*allocate)(struct ion_heap *heap,
                        struct ion_buffer *buffer, unsigned long len,
                        unsigned long flags);
        void (*free)(struct ion_buffer *buffer);
        void * (*map_kernel)(struct ion_heap *heap, struct ion_buffer *buffer);
        void (*unmap_kernel)(struct ion_heap *heap, struct ion_buffer *buffer);
        int (*map_user)(struct ion_heap *mapper, struct ion_buffer *buffer,
                        struct vm_area_struct *vma);
        int (*shrink)(struct ion_heap *heap, gfp_t gfp_mask, int nr_to_scan);
};

/**
 * heap flags - flags between the heaps and core ion code
 */
#define ION_HEAP_FLAG_DEFER_FREE (1 << 0)

/**
 * private flags - flags internal to ion
 */
/*
 * Buffer is being freed from a shrinker function. Skip any possible
 * heap-specific caching mechanism (e.g. page pools). Guarantees that
 * any buffer storage that came from the system allocator will be
 * returned to the system allocator.
 */
#define ION_PRIV_FLAG_SHRINKER_FREE (1 << 0)

/**
 * struct ion_heap - represents a heap in the system
 * @node:               rb node to put the heap on the device's tree of heaps
 * @dev:                back pointer to the ion_device
 * @type:               type of heap
 * @ops:                ops struct as above
 * @flags:              flags
 * @id:                 id of heap, also indicates priority of this heap when
 *                      allocating.  These are specified by platform data and
 *                      MUST be unique
 * @name:               used for debugging
 * @shrinker:           a shrinker for the heap
 * @free_list:          free list head if deferred free is used
 * @free_list_size      size of the deferred free list in bytes
 * @lock:               protects the free list
 * @waitqueue:          queue to wait on from deferred free thread
 * @task:               task struct of deferred free thread
 * @debug_show:         called when heap debug file is read to add any
 *                      heap specific debug info to output
 *
 * Represents a pool of memory from which buffers can be made.  In some
 * systems the only heap is regular system memory allocated via vmalloc.
 * On others, some blocks might require large physically contiguous buffers
 * that are allocated from a specially reserved heap.
 */
struct ion_heap {
        struct plist_node node;
        struct ion_device *dev;
        enum ion_heap_type type;
        struct ion_heap_ops *ops;
        unsigned long flags;
        unsigned int id;
        const char *name;
        struct shrinker shrinker;
        struct list_head free_list;
        size_t free_list_size;
        spinlock_t free_lock;
        wait_queue_head_t waitqueue;
        struct task_struct *task;

        int (*debug_show)(struct ion_heap *heap, struct seq_file *, void *);
};

/**
 * ion_buffer_cached - this ion buffer is cached
 * @buffer:             buffer
 *
 * indicates whether this ion buffer is cached
 */
bool ion_buffer_cached(struct ion_buffer *buffer);

/**
 * ion_buffer_fault_user_mappings - fault in user mappings of this buffer
 * @buffer:             buffer
 *
 * indicates whether userspace mappings of this buffer will be faulted
 * in, this can affect how buffers are allocated from the heap.
 */
bool ion_buffer_fault_user_mappings(struct ion_buffer *buffer);

/**
 * ion_device_add_heap - adds a heap to the ion device
 * @heap:               the heap to add
 */
void ion_device_add_heap(struct ion_heap *heap);

/**
 * some helpers for common operations on buffers using the sg_table
 * and vaddr fields
 */
void *ion_heap_map_kernel(struct ion_heap *heap, struct ion_buffer *buffer);
void ion_heap_unmap_kernel(struct ion_heap *heap, struct ion_buffer *buffer);
int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
                      struct vm_area_struct *vma);
int ion_heap_buffer_zero(struct ion_buffer *buffer);
int ion_heap_pages_zero(struct page *page, size_t size, pgprot_t pgprot);

int ion_alloc(size_t len,
                                unsigned int heap_id_mask,
                                unsigned int flags);

/**
 * ion_heap_init_shrinker
 * @heap:               the heap
 *
 * If a heap sets the ION_HEAP_FLAG_DEFER_FREE flag or defines the shrink op
 * this function will be called to setup a shrinker to shrink the freelists
 * and call the heap's shrink op.
 */
void ion_heap_init_shrinker(struct ion_heap *heap);

/**
 * ion_heap_init_deferred_free -- initialize deferred free functionality
 * @heap:               the heap
 *
 * If a heap sets the ION_HEAP_FLAG_DEFER_FREE flag this function will
 * be called to setup deferred frees. Calls to free the buffer will
 * return immediately and the actual free will occur some time later
 */
int ion_heap_init_deferred_free(struct ion_heap *heap);

/**
 * ion_heap_freelist_add - add a buffer to the deferred free list
 * @heap:               the heap
 * @buffer:             the buffer
 *
 * Adds an item to the deferred freelist.
 */
void ion_heap_freelist_add(struct ion_heap *heap, struct ion_buffer *buffer);

/**
 * ion_heap_freelist_drain - drain the deferred free list
 * @heap:               the heap
 * @size:               amount of memory to drain in bytes
 *
 * Drains the indicated amount of memory from the deferred freelist immediately.
 * Returns the total amount freed.  The total freed may be higher depending
 * on the size of the items in the list, or lower if there is insufficient
 * total memory on the freelist.
 */
size_t ion_heap_freelist_drain(struct ion_heap *heap, size_t size);

/**
 * ion_heap_freelist_shrink - drain the deferred free
 *                              list, skipping any heap-specific
 *                              pooling or caching mechanisms
 *
 * @heap:               the heap
 * @size:               amount of memory to drain in bytes
 *
 * Drains the indicated amount of memory from the deferred freelist immediately.
 * Returns the total amount freed.  The total freed may be higher depending
 * on the size of the items in the list, or lower if there is insufficient
 * total memory on the freelist.
 *
 * Unlike with @ion_heap_freelist_drain, don't put any pages back into
 * page pools or otherwise cache the pages. Everything must be
 * genuinely free'd back to the system. If you're free'ing from a
 * shrinker you probably want to use this. Note that this relies on
 * the heap.ops.free callback honoring the ION_PRIV_FLAG_SHRINKER_FREE
 * flag.
 */
size_t ion_heap_freelist_shrink(struct ion_heap *heap,
                                        size_t size);

/**
 * ion_heap_freelist_size - returns the size of the freelist in bytes
 * @heap:               the heap
 */
size_t ion_heap_freelist_size(struct ion_heap *heap);


/**
 * functions for creating and destroying a heap pool -- allows you
 * to keep a pool of pre allocated memory to use from your heap.  Keeping
 * a pool of memory that is ready for dma, ie any cached mapping have been
 * invalidated from the cache, provides a significant performance benefit on
 * many systems
 */

/**
 * struct ion_page_pool - pagepool struct
 * @high_count:         number of highmem items in the pool
 * @low_count:          number of lowmem items in the pool
 * @high_items:         list of highmem items
 * @low_items:          list of lowmem items
 * @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:               plist node for list of pools
 * @cached:             it's cached pool or not
 *
 * Allows you to keep a pool of pre allocated pages to use from your heap.
 * Keeping a pool of pages that is ready for dma, ie any cached mapping have
 * been invalidated from the cache, provides a significant performance benefit
 * on many systems
 */
struct ion_page_pool {
        int high_count;
        int low_count;
        bool cached;
        struct list_head high_items;
        struct list_head low_items;
        struct mutex mutex;
        gfp_t gfp_mask;
        unsigned int order;
        struct plist_node list;
};

struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order,
                                           bool cached);
void ion_page_pool_destroy(struct ion_page_pool *pool);
struct page *ion_page_pool_alloc(struct ion_page_pool *pool);
void ion_page_pool_free(struct ion_page_pool *pool, struct page *page);

/** ion_page_pool_shrink - shrinks the size of the memory cached in the pool
 * @pool:               the pool
 * @gfp_mask:           the memory type to reclaim
 * @nr_to_scan:         number of items to shrink in pages
 *
 * returns the number of items freed in pages
 */
int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
                          int nr_to_scan);

long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);

int ion_query_heaps(struct ion_heap_query *query);

#endif /* _ION_H */