1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * drivers/staging/android/ion/ion.h
4  *
5  * Copyright (C) 2011 Google, Inc.
6  */
7 
8 #ifndef _ION_H
9 #define _ION_H
10 
11 #include <linux/device.h>
12 #include <linux/dma-direction.h>
13 #include <linux/kref.h>
14 #include <linux/mm_types.h>
15 #include <linux/mutex.h>
16 #include <linux/rbtree.h>
17 #include <linux/sched.h>
18 #include <linux/shrinker.h>
19 #include <linux/types.h>
20 #include <linux/miscdevice.h>
21 
22 #include "../uapi/ion.h"
23 
24 /**
25  * struct ion_platform_heap - defines a heap in the given platform
26  * @type:	type of the heap from ion_heap_type enum
27  * @id:		unique identifier for heap.  When allocating higher numb ers
28  *		will be allocated from first.  At allocation these are passed
29  *		as a bit mask and therefore can not exceed ION_NUM_HEAP_IDS.
30  * @name:	used for debug purposes
31  * @base:	base address of heap in physical memory if applicable
32  * @size:	size of the heap in bytes if applicable
33  * @priv:	private info passed from the board file
34  *
35  * Provided by the board file.
36  */
37 struct ion_platform_heap {
38 	enum ion_heap_type type;
39 	unsigned int id;
40 	const char *name;
41 	phys_addr_t base;
42 	size_t size;
43 	phys_addr_t align;
44 	void *priv;
45 };
46 
47 /**
48  * struct ion_buffer - metadata for a particular buffer
49  * @ref:		reference count
50  * @node:		node in the ion_device buffers tree
51  * @dev:		back pointer to the ion_device
52  * @heap:		back pointer to the heap the buffer came from
53  * @flags:		buffer specific flags
54  * @private_flags:	internal buffer specific flags
55  * @size:		size of the buffer
56  * @priv_virt:		private data to the buffer representable as
57  *			a void *
58  * @lock:		protects the buffers cnt fields
59  * @kmap_cnt:		number of times the buffer is mapped to the kernel
60  * @vaddr:		the kernel mapping if kmap_cnt is not zero
61  * @sg_table:		the sg table for the buffer if dmap_cnt is not zero
62  */
63 struct ion_buffer {
64 	union {
65 		struct rb_node node;
66 		struct list_head list;
67 	};
68 	struct ion_device *dev;
69 	struct ion_heap *heap;
70 	unsigned long flags;
71 	unsigned long private_flags;
72 	size_t size;
73 	void *priv_virt;
74 	struct mutex lock;
75 	int kmap_cnt;
76 	void *vaddr;
77 	struct sg_table *sg_table;
78 	struct list_head attachments;
79 };
80 
81 void ion_buffer_destroy(struct ion_buffer *buffer);
82 
83 /**
84  * struct ion_device - the metadata of the ion device node
85  * @dev:		the actual misc device
86  * @buffers:		an rb tree of all the existing buffers
87  * @buffer_lock:	lock protecting the tree of buffers
88  * @lock:		rwsem protecting the tree of heaps and clients
89  */
90 struct ion_device {
91 	struct miscdevice dev;
92 	struct rb_root buffers;
93 	struct mutex buffer_lock;
94 	struct rw_semaphore lock;
95 	struct plist_head heaps;
96 	struct dentry *debug_root;
97 	int heap_cnt;
98 };
99 
100 /**
101  * struct ion_heap_ops - ops to operate on a given heap
102  * @allocate:		allocate memory
103  * @free:		free memory
104  * @map_kernel		map memory to the kernel
105  * @unmap_kernel	unmap memory to the kernel
106  * @map_user		map memory to userspace
107  *
108  * allocate, phys, and map_user return 0 on success, -errno on error.
109  * map_dma and map_kernel return pointer on success, ERR_PTR on
110  * error. @free will be called with ION_PRIV_FLAG_SHRINKER_FREE set in
111  * the buffer's private_flags when called from a shrinker. In that
112  * case, the pages being free'd must be truly free'd back to the
113  * system, not put in a page pool or otherwise cached.
114  */
115 struct ion_heap_ops {
116 	int (*allocate)(struct ion_heap *heap,
117 			struct ion_buffer *buffer, unsigned long len,
118 			unsigned long flags);
119 	void (*free)(struct ion_buffer *buffer);
120 	void * (*map_kernel)(struct ion_heap *heap, struct ion_buffer *buffer);
121 	void (*unmap_kernel)(struct ion_heap *heap, struct ion_buffer *buffer);
122 	int (*map_user)(struct ion_heap *mapper, struct ion_buffer *buffer,
123 			struct vm_area_struct *vma);
124 	int (*shrink)(struct ion_heap *heap, gfp_t gfp_mask, int nr_to_scan);
125 };
126 
127 /**
128  * heap flags - flags between the heaps and core ion code
129  */
130 #define ION_HEAP_FLAG_DEFER_FREE BIT(0)
131 
132 /**
133  * private flags - flags internal to ion
134  */
135 /*
136  * Buffer is being freed from a shrinker function. Skip any possible
137  * heap-specific caching mechanism (e.g. page pools). Guarantees that
138  * any buffer storage that came from the system allocator will be
139  * returned to the system allocator.
140  */
141 #define ION_PRIV_FLAG_SHRINKER_FREE BIT(0)
142 
143 /**
144  * struct ion_heap - represents a heap in the system
145  * @node:		rb node to put the heap on the device's tree of heaps
146  * @dev:		back pointer to the ion_device
147  * @type:		type of heap
148  * @ops:		ops struct as above
149  * @flags:		flags
150  * @id:			id of heap, also indicates priority of this heap when
151  *			allocating.  These are specified by platform data and
152  *			MUST be unique
153  * @name:		used for debugging
154  * @shrinker:		a shrinker for the heap
155  * @free_list:		free list head if deferred free is used
156  * @free_list_size	size of the deferred free list in bytes
157  * @lock:		protects the free list
158  * @waitqueue:		queue to wait on from deferred free thread
159  * @task:		task struct of deferred free thread
160  * @debug_show:		called when heap debug file is read to add any
161  *			heap specific debug info to output
162  *
163  * Represents a pool of memory from which buffers can be made.  In some
164  * systems the only heap is regular system memory allocated via vmalloc.
165  * On others, some blocks might require large physically contiguous buffers
166  * that are allocated from a specially reserved heap.
167  */
168 struct ion_heap {
169 	struct plist_node node;
170 	struct ion_device *dev;
171 	enum ion_heap_type type;
172 	struct ion_heap_ops *ops;
173 	unsigned long flags;
174 	unsigned int id;
175 	const char *name;
176 	struct shrinker shrinker;
177 	struct list_head free_list;
178 	size_t free_list_size;
179 	spinlock_t free_lock;
180 	wait_queue_head_t waitqueue;
181 	struct task_struct *task;
182 
183 	int (*debug_show)(struct ion_heap *heap, struct seq_file *s,
184 			  void *unused);
185 };
186 
187 /**
188  * ion_device_add_heap - adds a heap to the ion device
189  * @heap:		the heap to add
190  */
191 void ion_device_add_heap(struct ion_heap *heap);
192 
193 /**
194  * some helpers for common operations on buffers using the sg_table
195  * and vaddr fields
196  */
197 void *ion_heap_map_kernel(struct ion_heap *heap, struct ion_buffer *buffer);
198 void ion_heap_unmap_kernel(struct ion_heap *heap, struct ion_buffer *buffer);
199 int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
200 		      struct vm_area_struct *vma);
201 int ion_heap_buffer_zero(struct ion_buffer *buffer);
202 int ion_heap_pages_zero(struct page *page, size_t size, pgprot_t pgprot);
203 
204 int ion_alloc(size_t len,
205 	      unsigned int heap_id_mask,
206 	      unsigned int flags);
207 
208 /**
209  * ion_heap_init_shrinker
210  * @heap:		the heap
211  *
212  * If a heap sets the ION_HEAP_FLAG_DEFER_FREE flag or defines the shrink op
213  * this function will be called to setup a shrinker to shrink the freelists
214  * and call the heap's shrink op.
215  */
216 int ion_heap_init_shrinker(struct ion_heap *heap);
217 
218 /**
219  * ion_heap_init_deferred_free -- initialize deferred free functionality
220  * @heap:		the heap
221  *
222  * If a heap sets the ION_HEAP_FLAG_DEFER_FREE flag this function will
223  * be called to setup deferred frees. Calls to free the buffer will
224  * return immediately and the actual free will occur some time later
225  */
226 int ion_heap_init_deferred_free(struct ion_heap *heap);
227 
228 /**
229  * ion_heap_freelist_add - add a buffer to the deferred free list
230  * @heap:		the heap
231  * @buffer:		the buffer
232  *
233  * Adds an item to the deferred freelist.
234  */
235 void ion_heap_freelist_add(struct ion_heap *heap, struct ion_buffer *buffer);
236 
237 /**
238  * ion_heap_freelist_drain - drain the deferred free list
239  * @heap:		the heap
240  * @size:		amount of memory to drain in bytes
241  *
242  * Drains the indicated amount of memory from the deferred freelist immediately.
243  * Returns the total amount freed.  The total freed may be higher depending
244  * on the size of the items in the list, or lower if there is insufficient
245  * total memory on the freelist.
246  */
247 size_t ion_heap_freelist_drain(struct ion_heap *heap, size_t size);
248 
249 /**
250  * ion_heap_freelist_shrink - drain the deferred free
251  *				list, skipping any heap-specific
252  *				pooling or caching mechanisms
253  *
254  * @heap:		the heap
255  * @size:		amount of memory to drain in bytes
256  *
257  * Drains the indicated amount of memory from the deferred freelist immediately.
258  * Returns the total amount freed.  The total freed may be higher depending
259  * on the size of the items in the list, or lower if there is insufficient
260  * total memory on the freelist.
261  *
262  * Unlike with @ion_heap_freelist_drain, don't put any pages back into
263  * page pools or otherwise cache the pages. Everything must be
264  * genuinely free'd back to the system. If you're free'ing from a
265  * shrinker you probably want to use this. Note that this relies on
266  * the heap.ops.free callback honoring the ION_PRIV_FLAG_SHRINKER_FREE
267  * flag.
268  */
269 size_t ion_heap_freelist_shrink(struct ion_heap *heap,
270 				size_t size);
271 
272 /**
273  * ion_heap_freelist_size - returns the size of the freelist in bytes
274  * @heap:		the heap
275  */
276 size_t ion_heap_freelist_size(struct ion_heap *heap);
277 
278 /**
279  * functions for creating and destroying a heap pool -- allows you
280  * to keep a pool of pre allocated memory to use from your heap.  Keeping
281  * a pool of memory that is ready for dma, ie any cached mapping have been
282  * invalidated from the cache, provides a significant performance benefit on
283  * many systems
284  */
285 
286 /**
287  * struct ion_page_pool - pagepool struct
288  * @high_count:		number of highmem items in the pool
289  * @low_count:		number of lowmem items in the pool
290  * @high_items:		list of highmem items
291  * @low_items:		list of lowmem items
292  * @mutex:		lock protecting this struct and especially the count
293  *			item list
294  * @gfp_mask:		gfp_mask to use from alloc
295  * @order:		order of pages in the pool
296  * @list:		plist node for list of pools
297  *
298  * Allows you to keep a pool of pre allocated pages to use from your heap.
299  * Keeping a pool of pages that is ready for dma, ie any cached mapping have
300  * been invalidated from the cache, provides a significant performance benefit
301  * on many systems
302  */
303 struct ion_page_pool {
304 	int high_count;
305 	int low_count;
306 	struct list_head high_items;
307 	struct list_head low_items;
308 	struct mutex mutex;
309 	gfp_t gfp_mask;
310 	unsigned int order;
311 	struct plist_node list;
312 };
313 
314 struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order);
315 void ion_page_pool_destroy(struct ion_page_pool *pool);
316 struct page *ion_page_pool_alloc(struct ion_page_pool *pool);
317 void ion_page_pool_free(struct ion_page_pool *pool, struct page *page);
318 
319 /** ion_page_pool_shrink - shrinks the size of the memory cached in the pool
320  * @pool:		the pool
321  * @gfp_mask:		the memory type to reclaim
322  * @nr_to_scan:		number of items to shrink in pages
323  *
324  * returns the number of items freed in pages
325  */
326 int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
327 			 int nr_to_scan);
328 
329 long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
330 
331 int ion_query_heaps(struct ion_heap_query *query);
332 
333 #endif /* _ION_H */
334