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_ggtt_view_type and struct i915_ggtt_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_ggtt_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_ggtt_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_ggtt_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.ggtt_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_ggtt_view does not need to be persistent (left around after
94 * calling the core API functions).
95 *
96 */
97
98 struct intel_remapped_plane_info {
99 /* in gtt pages */
100 unsigned int width, height, stride, offset;
101 } __packed;
102
103 struct intel_remapped_info {
104 struct intel_remapped_plane_info plane[2];
105 unsigned int unused_mbz;
106 } __packed;
107
108 struct intel_rotation_info {
109 struct intel_remapped_plane_info plane[2];
110 } __packed;
111
112 struct intel_partial_info {
113 u64 offset;
114 unsigned int size;
115 } __packed;
116
117 enum i915_ggtt_view_type {
118 I915_GGTT_VIEW_NORMAL = 0,
119 I915_GGTT_VIEW_ROTATED = sizeof(struct intel_rotation_info),
120 I915_GGTT_VIEW_PARTIAL = sizeof(struct intel_partial_info),
121 I915_GGTT_VIEW_REMAPPED = sizeof(struct intel_remapped_info),
122 };
123
assert_i915_gem_gtt_types(void)124 static inline void assert_i915_gem_gtt_types(void)
125 {
126 BUILD_BUG_ON(sizeof(struct intel_rotation_info) != 8*sizeof(unsigned int));
127 BUILD_BUG_ON(sizeof(struct intel_partial_info) != sizeof(u64) + sizeof(unsigned int));
128 BUILD_BUG_ON(sizeof(struct intel_remapped_info) != 9*sizeof(unsigned int));
129
130 /* Check that rotation/remapped shares offsets for simplicity */
131 BUILD_BUG_ON(offsetof(struct intel_remapped_info, plane[0]) !=
132 offsetof(struct intel_rotation_info, plane[0]));
133 BUILD_BUG_ON(offsetofend(struct intel_remapped_info, plane[1]) !=
134 offsetofend(struct intel_rotation_info, plane[1]));
135
136 /* As we encode the size of each branch inside the union into its type,
137 * we have to be careful that each branch has a unique size.
138 */
139 switch ((enum i915_ggtt_view_type)0) {
140 case I915_GGTT_VIEW_NORMAL:
141 case I915_GGTT_VIEW_PARTIAL:
142 case I915_GGTT_VIEW_ROTATED:
143 case I915_GGTT_VIEW_REMAPPED:
144 /* gcc complains if these are identical cases */
145 break;
146 }
147 }
148
149 struct i915_ggtt_view {
150 enum i915_ggtt_view_type type;
151 union {
152 /* Members need to contain no holes/padding */
153 struct intel_partial_info partial;
154 struct intel_rotation_info rotated;
155 struct intel_remapped_info remapped;
156 };
157 };
158
159 /**
160 * DOC: Virtual Memory Address
161 *
162 * A VMA represents a GEM BO that is bound into an address space. Therefore, a
163 * VMA's presence cannot be guaranteed before binding, or after unbinding the
164 * object into/from the address space.
165 *
166 * To make things as simple as possible (ie. no refcounting), a VMA's lifetime
167 * will always be <= an objects lifetime. So object refcounting should cover us.
168 */
169 struct i915_vma {
170 struct drm_mm_node node;
171
172 struct i915_address_space *vm;
173 const struct i915_vma_ops *ops;
174
175 struct drm_i915_gem_object *obj;
176 struct dma_resv *resv; /** Alias of obj->resv */
177
178 struct sg_table *pages;
179 void __iomem *iomap;
180 void *private; /* owned by creator */
181
182 struct i915_fence_reg *fence;
183
184 u64 size;
185 u64 display_alignment;
186 struct i915_page_sizes page_sizes;
187
188 /* mmap-offset associated with fencing for this vma */
189 struct i915_mmap_offset *mmo;
190
191 u32 fence_size;
192 u32 fence_alignment;
193
194 /**
195 * Count of the number of times this vma has been opened by different
196 * handles (but same file) for execbuf, i.e. the number of aliases
197 * that exist in the ctx->handle_vmas LUT for this vma.
198 */
199 struct kref ref;
200 atomic_t open_count;
201 atomic_t flags;
202 /**
203 * How many users have pinned this object in GTT space.
204 *
205 * This is a tightly bound, fairly small number of users, so we
206 * stuff inside the flags field so that we can both check for overflow
207 * and detect a no-op i915_vma_pin() in a single check, while also
208 * pinning the vma.
209 *
210 * The worst case display setup would have the same vma pinned for
211 * use on each plane on each crtc, while also building the next atomic
212 * state and holding a pin for the length of the cleanup queue. In the
213 * future, the flip queue may be increased from 1.
214 * Estimated worst case: 3 [qlen] * 4 [max crtcs] * 7 [max planes] = 84
215 *
216 * For GEM, the number of concurrent users for pwrite/pread is
217 * unbounded. For execbuffer, it is currently one but will in future
218 * be extended to allow multiple clients to pin vma concurrently.
219 *
220 * We also use suballocated pages, with each suballocation claiming
221 * its own pin on the shared vma. At present, this is limited to
222 * exclusive cachelines of a single page, so a maximum of 64 possible
223 * users.
224 */
225 #define I915_VMA_PIN_MASK 0x3ff
226 #define I915_VMA_OVERFLOW 0x200
227
228 /** Flags and address space this VMA is bound to */
229 #define I915_VMA_GLOBAL_BIND_BIT 10
230 #define I915_VMA_LOCAL_BIND_BIT 11
231
232 #define I915_VMA_GLOBAL_BIND ((int)BIT(I915_VMA_GLOBAL_BIND_BIT))
233 #define I915_VMA_LOCAL_BIND ((int)BIT(I915_VMA_LOCAL_BIND_BIT))
234
235 #define I915_VMA_BIND_MASK (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND)
236
237 #define I915_VMA_ALLOC_BIT 12
238
239 #define I915_VMA_ERROR_BIT 13
240 #define I915_VMA_ERROR ((int)BIT(I915_VMA_ERROR_BIT))
241
242 #define I915_VMA_GGTT_BIT 14
243 #define I915_VMA_CAN_FENCE_BIT 15
244 #define I915_VMA_USERFAULT_BIT 16
245 #define I915_VMA_GGTT_WRITE_BIT 17
246
247 #define I915_VMA_GGTT ((int)BIT(I915_VMA_GGTT_BIT))
248 #define I915_VMA_CAN_FENCE ((int)BIT(I915_VMA_CAN_FENCE_BIT))
249 #define I915_VMA_USERFAULT ((int)BIT(I915_VMA_USERFAULT_BIT))
250 #define I915_VMA_GGTT_WRITE ((int)BIT(I915_VMA_GGTT_WRITE_BIT))
251
252 struct i915_active active;
253
254 #define I915_VMA_PAGES_BIAS 24
255 #define I915_VMA_PAGES_ACTIVE (BIT(24) | 1)
256 atomic_t pages_count; /* number of active binds to the pages */
257 struct mutex pages_mutex; /* protect acquire/release of backing pages */
258
259 /**
260 * Support different GGTT views into the same object.
261 * This means there can be multiple VMA mappings per object and per VM.
262 * i915_ggtt_view_type is used to distinguish between those entries.
263 * The default one of zero (I915_GGTT_VIEW_NORMAL) is default and also
264 * assumed in GEM functions which take no ggtt view parameter.
265 */
266 struct i915_ggtt_view ggtt_view;
267
268 /** This object's place on the active/inactive lists */
269 struct list_head vm_link;
270
271 struct list_head obj_link; /* Link in the object's VMA list */
272 struct rb_node obj_node;
273 struct hlist_node obj_hash;
274
275 /** This vma's place in the eviction list */
276 struct list_head evict_link;
277
278 struct list_head closed_link;
279 };
280
281 #endif
282
283
