/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (c) 2019, The Linux Foundation. All rights reserved.
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*/
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#ifndef _ION_KERNEL_H
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#define _ION_KERNEL_H
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#include <linux/dma-buf.h>
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/dma-direction.h>
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#include <linux/kref.h>
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#include <linux/mm_types.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/rbtree.h>
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#include <linux/sched.h>
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#include <linux/shrinker.h>
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#include <linux/types.h>
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#include <uapi/linux/ion.h>
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/**
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* struct ion_buffer - metadata for a particular buffer
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* @list: element in list of deferred freeable buffers
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* @heap: back pointer to the heap the buffer came from
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* @flags: buffer specific flags
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* @private_flags: internal buffer specific flags
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* @size: size of the buffer
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* @priv_virt: private data to the buffer representable as
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* a void *
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* @lock: protects the buffers cnt fields
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* @kmap_cnt: number of times the buffer is mapped to the kernel
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* @vaddr: the kernel mapping if kmap_cnt is not zero
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* @sg_table: the sg table for the buffer
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* @attachments: list of devices attached to this buffer
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*/
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struct ion_buffer {
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struct list_head list;
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struct ion_heap *heap;
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unsigned long flags;
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unsigned long private_flags;
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size_t size;
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void *priv_virt;
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struct mutex lock;
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int kmap_cnt;
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void *vaddr;
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struct sg_table *sg_table;
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struct list_head attachments;
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};
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/**
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* struct ion_heap_ops - ops to operate on a given heap
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* @allocate: allocate memory
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* @free: free memory
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* @get_pool_size: get pool size in pages
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*
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* allocate returns 0 on success, -errno on error.
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* map_dma and map_kernel return pointer on success, ERR_PTR on
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* error. @free will be called with ION_PRIV_FLAG_SHRINKER_FREE set in
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* the buffer's private_flags when called from a shrinker. In that
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* case, the pages being free'd must be truly free'd back to the
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* system, not put in a page pool or otherwise cached.
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*/
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struct ion_heap_ops {
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int (*allocate)(struct ion_heap *heap,
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struct ion_buffer *buffer, unsigned long len,
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unsigned long flags);
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void (*free)(struct ion_buffer *buffer);
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int (*shrink)(struct ion_heap *heap, gfp_t gfp_mask, int nr_to_scan);
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long (*get_pool_size)(struct ion_heap *heap);
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};
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/**
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* heap flags - flags between the heaps and core ion code
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*/
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#define ION_HEAP_FLAG_DEFER_FREE BIT(0)
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/**
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* private flags - flags internal to ion
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*/
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/*
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* Buffer is being freed from a shrinker function. Skip any possible
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* heap-specific caching mechanism (e.g. page pools). Guarantees that
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* any buffer storage that came from the system allocator will be
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* returned to the system allocator.
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*/
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#define ION_PRIV_FLAG_SHRINKER_FREE BIT(0)
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/**
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* struct ion_heap - represents a heap in the system
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* @node: rb node to put the heap on the device's tree of heaps
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* @type: type of heap
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* @ops: ops struct as above
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* @buf_ops: dma_buf ops specific to the heap implementation.
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* @flags: flags
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* @id: id of heap, also indicates priority of this heap when
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* allocating. These are specified by platform data and
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* MUST be unique
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* @name: used for debugging
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* @owner: kernel module that implements this heap
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* @shrinker: a shrinker for the heap
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* @free_list: free list head if deferred free is used
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* @free_list_size size of the deferred free list in bytes
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* @lock: protects the free list
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* @waitqueue: queue to wait on from deferred free thread
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* @task: task struct of deferred free thread
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* @num_of_buffers the number of currently allocated buffers
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* @num_of_alloc_bytes the number of allocated bytes
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* @alloc_bytes_wm the number of allocated bytes watermark
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*
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* Represents a pool of memory from which buffers can be made. In some
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* systems the only heap is regular system memory allocated via vmalloc.
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* On others, some blocks might require large physically contiguous buffers
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* that are allocated from a specially reserved heap.
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*/
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struct ion_heap {
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struct plist_node node;
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enum ion_heap_type type;
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struct ion_heap_ops *ops;
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struct dma_buf_ops buf_ops;
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unsigned long flags;
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unsigned int id;
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const char *name;
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struct module *owner;
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/* deferred free support */
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struct shrinker shrinker;
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struct list_head free_list;
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size_t free_list_size;
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spinlock_t free_lock;
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wait_queue_head_t waitqueue;
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struct task_struct *task;
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/* heap statistics */
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u64 num_of_buffers;
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u64 num_of_alloc_bytes;
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u64 alloc_bytes_wm;
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/* protect heap statistics */
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spinlock_t stat_lock;
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/* heap's debugfs root */
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struct dentry *debugfs_dir;
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};
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#define ion_device_add_heap(heap) __ion_device_add_heap(heap, THIS_MODULE)
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/**
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* struct ion_dma_buf_attachment - hold device-table attachment data for buffer
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* @dev: device attached to the buffer.
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* @table: cached mapping.
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* @list: list of ion_dma_buf_attachment.
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*/
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struct ion_dma_buf_attachment {
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struct device *dev;
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struct sg_table *table;
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struct list_head list;
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bool mapped:1;
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};
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#ifdef CONFIG_ION
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/**
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* __ion_device_add_heap - adds a heap to the ion device
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*
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* @heap: the heap to add
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*
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* Returns 0 on success, negative error otherwise.
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*/
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int __ion_device_add_heap(struct ion_heap *heap, struct module *owner);
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/**
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* ion_device_remove_heap - removes a heap from ion device
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*
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* @heap: pointer to the heap to be removed
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*/
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void ion_device_remove_heap(struct ion_heap *heap);
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/**
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* ion_heap_init_shrinker
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* @heap: the heap
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*
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* If a heap sets the ION_HEAP_FLAG_DEFER_FREE flag or defines the shrink op
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* this function will be called to setup a shrinker to shrink the freelists
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* and call the heap's shrink op.
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*/
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int ion_heap_init_shrinker(struct ion_heap *heap);
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/**
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* ion_heap_init_deferred_free -- initialize deferred free functionality
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* @heap: the heap
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*
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* If a heap sets the ION_HEAP_FLAG_DEFER_FREE flag this function will
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* be called to setup deferred frees. Calls to free the buffer will
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* return immediately and the actual free will occur some time later
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*/
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int ion_heap_init_deferred_free(struct ion_heap *heap);
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/**
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* ion_heap_freelist_add - add a buffer to the deferred free list
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* @heap: the heap
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* @buffer: the buffer
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*
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* Adds an item to the deferred freelist.
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*/
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void ion_heap_freelist_add(struct ion_heap *heap, struct ion_buffer *buffer);
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/**
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* ion_heap_freelist_drain - drain the deferred free list
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* @heap: the heap
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* @size: amount of memory to drain in bytes
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*
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* Drains the indicated amount of memory from the deferred freelist immediately.
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* Returns the total amount freed. The total freed may be higher depending
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* on the size of the items in the list, or lower if there is insufficient
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* total memory on the freelist.
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*/
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size_t ion_heap_freelist_drain(struct ion_heap *heap, size_t size);
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/**
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* ion_heap_freelist_shrink - drain the deferred free
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* list, skipping any heap-specific
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* pooling or caching mechanisms
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*
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* @heap: the heap
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* @size: amount of memory to drain in bytes
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*
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* Drains the indicated amount of memory from the deferred freelist immediately.
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* Returns the total amount freed. The total freed may be higher depending
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* on the size of the items in the list, or lower if there is insufficient
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* total memory on the freelist.
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*
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* Unlike with @ion_heap_freelist_drain, don't put any pages back into
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* page pools or otherwise cache the pages. Everything must be
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* genuinely free'd back to the system. If you're free'ing from a
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* shrinker you probably want to use this. Note that this relies on
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* the heap.ops.free callback honoring the ION_PRIV_FLAG_SHRINKER_FREE
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* flag.
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*/
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size_t ion_heap_freelist_shrink(struct ion_heap *heap,
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size_t size);
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/**
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* ion_heap_freelist_size - returns the size of the freelist in bytes
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* @heap: the heap
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*/
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size_t ion_heap_freelist_size(struct ion_heap *heap);
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/**
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* ion_heap_map_kernel - map the ion_buffer in kernel virtual address space.
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*
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* @heap: the heap
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* @buffer: buffer to be mapped
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*
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* Maps the buffer using vmap(). The function respects cache flags for the
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* buffer and creates the page table entries accordingly. Returns virtual
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* address at the beginning of the buffer or ERR_PTR.
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*/
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void *ion_heap_map_kernel(struct ion_heap *heap, struct ion_buffer *buffer);
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/**
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* ion_heap_unmap_kernel - unmap ion_buffer
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*
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* @buffer: buffer to be unmapped
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*
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* ION wrapper for vunmap() of the ion buffer.
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*/
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void ion_heap_unmap_kernel(struct ion_heap *heap, struct ion_buffer *buffer);
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/**
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* ion_heap_map_user - map given ion buffer in provided vma
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*
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* @heap: the heap this buffer belongs to
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* @buffer: Ion buffer to be mapped
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* @vma: vma of the process where buffer should be mapped.
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*
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* Maps the buffer using remap_pfn_range() into specific process's vma starting
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* with vma->vm_start. The vma size is expected to be >= ion buffer size.
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* If not, a partial buffer mapping may be created. Returns 0 on success.
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*/
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int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
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struct vm_area_struct *vma);
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/* ion_buffer_zero - zeroes out an ion buffer respecting the ION_FLAGs.
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*
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* @buffer: ion_buffer to zero
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*
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* Returns 0 on success, negative error otherwise.
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*/
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int ion_buffer_zero(struct ion_buffer *buffer);
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/**
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* ion_buffer_prep_noncached - flush cache before non-cached mapping
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*
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* @buffer: ion_buffer to flush
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*
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* The memory allocated by the heap could be in the CPU cache. To map
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* this memory as non-cached, we need to flush the associated cache
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* first. Without the flush, it is possible for stale dirty cache lines
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* to be evicted after the ION client started writing into this buffer,
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* leading to data corruption.
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*/
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void ion_buffer_prep_noncached(struct ion_buffer *buffer);
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/**
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* ion_alloc - Allocates an ion buffer of given size from given heap
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*
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* @len: size of the buffer to be allocated.
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* @heap_id_mask: a bitwise maks of heap ids to allocate from
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* @flags: ION_BUFFER_XXXX flags for the new buffer.
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*
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* The function exports a dma_buf object for the new ion buffer internally
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* and returns that to the caller. So, the buffer is ready to be used by other
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* drivers immediately. Returns ERR_PTR in case of failure.
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*/
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struct dma_buf *ion_alloc(size_t len, unsigned int heap_id_mask,
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unsigned int flags);
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/**
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* ion_free - Releases the ion buffer.
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*
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* @buffer: ion buffer to be released
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*/
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int ion_free(struct ion_buffer *buffer);
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/**
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* ion_query_heaps_kernel - Returns information about available heaps to
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* in-kernel clients.
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*
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* @hdata: pointer to array of struct ion_heap_data.
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* @size: size of @hdata array.
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*
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* Returns the number of available heaps and populates @hdata with information
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* regarding the same. When invoked with @size as 0, the function with return
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* the number of available heaps without modifying @hdata. When the number of
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* available heaps is higher than @size, @size is returned instead of the
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* actual number of available heaps.
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*/
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size_t ion_query_heaps_kernel(struct ion_heap_data *hdata, size_t size);
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#else
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static inline int __ion_device_add_heap(struct ion_heap *heap,
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struct module *owner)
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{
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return -ENODEV;
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}
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static inline int ion_heap_init_shrinker(struct ion_heap *heap)
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{
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return -ENODEV;
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}
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static inline int ion_heap_init_deferred_free(struct ion_heap *heap)
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{
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return -ENODEV;
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}
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static inline void ion_heap_freelist_add(struct ion_heap *heap,
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struct ion_buffer *buffer) {}
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static inline size_t ion_heap_freelist_drain(struct ion_heap *heap, size_t size)
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{
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return -ENODEV;
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}
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static inline size_t ion_heap_freelist_shrink(struct ion_heap *heap,
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size_t size)
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{
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return -ENODEV;
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}
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static inline size_t ion_heap_freelist_size(struct ion_heap *heap)
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{
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return -ENODEV;
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}
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static inline void *ion_heap_map_kernel(struct ion_heap *heap,
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struct ion_buffer *buffer)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void ion_heap_unmap_kernel(struct ion_heap *heap,
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struct ion_buffer *buffer) {}
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static inline int ion_heap_map_user(struct ion_heap *heap,
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struct ion_buffer *buffer,
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struct vm_area_struct *vma)
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{
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return -ENODEV;
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}
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static inline int ion_buffer_zero(struct ion_buffer *buffer)
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{
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return -EINVAL;
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}
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static inline void ion_buffer_prep_noncached(struct ion_buffer *buffer) {}
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static inline struct dma_buf *ion_alloc(size_t len, unsigned int heap_id_mask,
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unsigned int flags)
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{
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return ERR_PTR(-ENOMEM);
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}
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static inline int ion_free(struct ion_buffer *buffer)
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{
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return 0;
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}
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static inline size_t ion_query_heaps_kernel(struct ion_heap_data *hdata,
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size_t size)
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{
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return 0;
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}
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#endif /* CONFIG_ION */
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#endif /* _ION_KERNEL_H */
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