1 /* SPDX-License-Identifier: MIT */
2 /*
3  * Copyright © 2016 Intel Corporation
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice (including the next
13  * paragraph) shall be included in all copies or substantial portions of the
14  * Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  *
24  */
25 
26 #ifndef __I915_VMA_TYPES_H__
27 #define __I915_VMA_TYPES_H__
28 
29 #include <linux/rbtree.h>
30 
31 #include <drm/drm_mm.h>
32 
33 #include "gem/i915_gem_object_types.h"
34 
35 enum i915_cache_level;
36 
37 /**
38  * DOC: Global GTT views
39  *
40  * Background and previous state
41  *
42  * Historically objects could exists (be bound) in global GTT space only as
43  * singular instances with a view representing all of the object's backing pages
44  * in a linear fashion. This view will be called a normal view.
45  *
46  * To support multiple views of the same object, where the number of mapped
47  * pages is not equal to the backing store, or where the layout of the pages
48  * is not linear, concept of a GGTT view was added.
49  *
50  * One example of an alternative view is a stereo display driven by a single
51  * image. In this case we would have a framebuffer looking like this
52  * (2x2 pages):
53  *
54  *    12
55  *    34
56  *
57  * Above would represent a normal GGTT view as normally mapped for GPU or CPU
58  * rendering. In contrast, fed to the display engine would be an alternative
59  * view which could look something like this:
60  *
61  *   1212
62  *   3434
63  *
64  * In this example both the size and layout of pages in the alternative view is
65  * different from the normal view.
66  *
67  * Implementation and usage
68  *
69  * GGTT views are implemented using VMAs and are distinguished via enum
70  * i915_gtt_view_type and struct i915_gtt_view.
71  *
72  * A new flavour of core GEM functions which work with GGTT bound objects were
73  * added with the _ggtt_ infix, and sometimes with _view postfix to avoid
74  * renaming  in large amounts of code. They take the struct i915_gtt_view
75  * parameter encapsulating all metadata required to implement a view.
76  *
77  * As a helper for callers which are only interested in the normal view,
78  * globally const i915_gtt_view_normal singleton instance exists. All old core
79  * GEM API functions, the ones not taking the view parameter, are operating on,
80  * or with the normal GGTT view.
81  *
82  * Code wanting to add or use a new GGTT view needs to:
83  *
84  * 1. Add a new enum with a suitable name.
85  * 2. Extend the metadata in the i915_gtt_view structure if required.
86  * 3. Add support to i915_get_vma_pages().
87  *
88  * New views are required to build a scatter-gather table from within the
89  * i915_get_vma_pages function. This table is stored in the vma.gtt_view and
90  * exists for the lifetime of an VMA.
91  *
92  * Core API is designed to have copy semantics which means that passed in
93  * struct i915_gtt_view does not need to be persistent (left around after
94  * calling the core API functions).
95  *
96  */
97 
98 struct i915_vma_resource;
99 
100 struct intel_remapped_plane_info {
101 	/* in gtt pages */
102 	u32 offset:31;
103 	u32 linear:1;
104 	union {
105 		/* in gtt pages for !linear */
106 		struct {
107 			u16 width;
108 			u16 height;
109 			u16 src_stride;
110 			u16 dst_stride;
111 		};
112 
113 		/* in gtt pages for linear */
114 		u32 size;
115 	};
116 } __packed;
117 
118 struct intel_remapped_info {
119 	struct intel_remapped_plane_info plane[4];
120 	/* in gtt pages */
121 	u32 plane_alignment;
122 } __packed;
123 
124 struct intel_rotation_info {
125 	struct intel_remapped_plane_info plane[2];
126 } __packed;
127 
128 struct intel_partial_info {
129 	u64 offset;
130 	unsigned int size;
131 } __packed;
132 
133 enum i915_gtt_view_type {
134 	I915_GTT_VIEW_NORMAL = 0,
135 	I915_GTT_VIEW_ROTATED = sizeof(struct intel_rotation_info),
136 	I915_GTT_VIEW_PARTIAL = sizeof(struct intel_partial_info),
137 	I915_GTT_VIEW_REMAPPED = sizeof(struct intel_remapped_info),
138 };
139 
assert_i915_gem_gtt_types(void)140 static inline void assert_i915_gem_gtt_types(void)
141 {
142 	BUILD_BUG_ON(sizeof(struct intel_rotation_info) != 2 * sizeof(u32) + 8 * sizeof(u16));
143 	BUILD_BUG_ON(sizeof(struct intel_partial_info) != sizeof(u64) + sizeof(unsigned int));
144 	BUILD_BUG_ON(sizeof(struct intel_remapped_info) != 5 * sizeof(u32) + 16 * sizeof(u16));
145 
146 	/* Check that rotation/remapped shares offsets for simplicity */
147 	BUILD_BUG_ON(offsetof(struct intel_remapped_info, plane[0]) !=
148 		     offsetof(struct intel_rotation_info, plane[0]));
149 	BUILD_BUG_ON(offsetofend(struct intel_remapped_info, plane[1]) !=
150 		     offsetofend(struct intel_rotation_info, plane[1]));
151 
152 	/* As we encode the size of each branch inside the union into its type,
153 	 * we have to be careful that each branch has a unique size.
154 	 */
155 	switch ((enum i915_gtt_view_type)0) {
156 	case I915_GTT_VIEW_NORMAL:
157 	case I915_GTT_VIEW_PARTIAL:
158 	case I915_GTT_VIEW_ROTATED:
159 	case I915_GTT_VIEW_REMAPPED:
160 		/* gcc complains if these are identical cases */
161 		break;
162 	}
163 }
164 
165 struct i915_gtt_view {
166 	enum i915_gtt_view_type type;
167 	union {
168 		/* Members need to contain no holes/padding */
169 		struct intel_partial_info partial;
170 		struct intel_rotation_info rotated;
171 		struct intel_remapped_info remapped;
172 	};
173 };
174 
175 /**
176  * DOC: Virtual Memory Address
177  *
178  * A VMA represents a GEM BO that is bound into an address space. Therefore, a
179  * VMA's presence cannot be guaranteed before binding, or after unbinding the
180  * object into/from the address space.
181  *
182  * To make things as simple as possible (ie. no refcounting), a VMA's lifetime
183  * will always be <= an objects lifetime. So object refcounting should cover us.
184  */
185 struct i915_vma {
186 	struct drm_mm_node node;
187 
188 	struct i915_address_space *vm;
189 	const struct i915_vma_ops *ops;
190 
191 	struct drm_i915_gem_object *obj;
192 
193 	struct sg_table *pages;
194 	void __iomem *iomap;
195 	void *private; /* owned by creator */
196 
197 	struct i915_fence_reg *fence;
198 
199 	u64 size;
200 	u64 display_alignment;
201 	struct i915_page_sizes page_sizes;
202 
203 	/* mmap-offset associated with fencing for this vma */
204 	struct i915_mmap_offset	*mmo;
205 
206 	u32 fence_size;
207 	u32 fence_alignment;
208 
209 	/**
210 	 * Count of the number of times this vma has been opened by different
211 	 * handles (but same file) for execbuf, i.e. the number of aliases
212 	 * that exist in the ctx->handle_vmas LUT for this vma.
213 	 */
214 	atomic_t open_count;
215 	atomic_t flags;
216 	/**
217 	 * How many users have pinned this object in GTT space.
218 	 *
219 	 * This is a tightly bound, fairly small number of users, so we
220 	 * stuff inside the flags field so that we can both check for overflow
221 	 * and detect a no-op i915_vma_pin() in a single check, while also
222 	 * pinning the vma.
223 	 *
224 	 * The worst case display setup would have the same vma pinned for
225 	 * use on each plane on each crtc, while also building the next atomic
226 	 * state and holding a pin for the length of the cleanup queue. In the
227 	 * future, the flip queue may be increased from 1.
228 	 * Estimated worst case: 3 [qlen] * 4 [max crtcs] * 7 [max planes] = 84
229 	 *
230 	 * For GEM, the number of concurrent users for pwrite/pread is
231 	 * unbounded. For execbuffer, it is currently one but will in future
232 	 * be extended to allow multiple clients to pin vma concurrently.
233 	 *
234 	 * We also use suballocated pages, with each suballocation claiming
235 	 * its own pin on the shared vma. At present, this is limited to
236 	 * exclusive cachelines of a single page, so a maximum of 64 possible
237 	 * users.
238 	 */
239 #define I915_VMA_PIN_MASK 0x3ff
240 #define I915_VMA_OVERFLOW 0x200
241 
242 	/** Flags and address space this VMA is bound to */
243 #define I915_VMA_GLOBAL_BIND_BIT 10
244 #define I915_VMA_LOCAL_BIND_BIT  11
245 
246 #define I915_VMA_GLOBAL_BIND	((int)BIT(I915_VMA_GLOBAL_BIND_BIT))
247 #define I915_VMA_LOCAL_BIND	((int)BIT(I915_VMA_LOCAL_BIND_BIT))
248 
249 #define I915_VMA_BIND_MASK (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND)
250 
251 #define I915_VMA_ERROR_BIT	12
252 #define I915_VMA_ERROR		((int)BIT(I915_VMA_ERROR_BIT))
253 
254 #define I915_VMA_GGTT_BIT	13
255 #define I915_VMA_CAN_FENCE_BIT	14
256 #define I915_VMA_USERFAULT_BIT	15
257 #define I915_VMA_GGTT_WRITE_BIT	16
258 
259 #define I915_VMA_GGTT		((int)BIT(I915_VMA_GGTT_BIT))
260 #define I915_VMA_CAN_FENCE	((int)BIT(I915_VMA_CAN_FENCE_BIT))
261 #define I915_VMA_USERFAULT	((int)BIT(I915_VMA_USERFAULT_BIT))
262 #define I915_VMA_GGTT_WRITE	((int)BIT(I915_VMA_GGTT_WRITE_BIT))
263 
264 #define I915_VMA_SCANOUT_BIT	17
265 #define I915_VMA_SCANOUT	((int)BIT(I915_VMA_SCANOUT_BIT))
266 
267 	struct i915_active active;
268 
269 #define I915_VMA_PAGES_BIAS 24
270 #define I915_VMA_PAGES_ACTIVE (BIT(24) | 1)
271 	atomic_t pages_count; /* number of active binds to the pages */
272 
273 	/**
274 	 * Whether we hold a reference on the vm dma_resv lock to temporarily
275 	 * block vm freeing until the vma is destroyed.
276 	 * Protected by the vm mutex.
277 	 */
278 	bool vm_ddestroy;
279 
280 	/**
281 	 * Support different GGTT views into the same object.
282 	 * This means there can be multiple VMA mappings per object and per VM.
283 	 * i915_gtt_view_type is used to distinguish between those entries.
284 	 * The default one of zero (I915_GTT_VIEW_NORMAL) is default and also
285 	 * assumed in GEM functions which take no ggtt view parameter.
286 	 */
287 	struct i915_gtt_view gtt_view;
288 
289 	/** This object's place on the active/inactive lists */
290 	struct list_head vm_link;
291 
292 	struct list_head obj_link; /* Link in the object's VMA list */
293 	struct rb_node obj_node;
294 	struct hlist_node obj_hash;
295 
296 	/** This vma's place in the eviction list */
297 	struct list_head evict_link;
298 
299 	struct list_head closed_link;
300 
301 	/** The async vma resource. Protected by the vm_mutex */
302 	struct i915_vma_resource *resource;
303 };
304 
305 #endif
306