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#include "i915_gtt_view_types.h"
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
98struct i915_vma_resource;
99
100static inline void assert_i915_gem_gtt_types(void)
101{
102 BUILD_BUG_ON(sizeof(struct intel_rotation_info) != 2 * sizeof(u32) + 8 * sizeof(u16));
103 BUILD_BUG_ON(sizeof(struct intel_partial_info) != sizeof(u64) + sizeof(unsigned int));
104 BUILD_BUG_ON(sizeof(struct intel_remapped_info) != 5 * sizeof(u32) + 16 * sizeof(u16));
105
106 /* Check that rotation/remapped shares offsets for simplicity */
107 BUILD_BUG_ON(offsetof(struct intel_remapped_info, plane[0]) !=
108 offsetof(struct intel_rotation_info, plane[0]));
109 BUILD_BUG_ON(offsetofend(struct intel_remapped_info, plane[1]) !=
110 offsetofend(struct intel_rotation_info, plane[1]));
111
112 /* As we encode the size of each branch inside the union into its type,
113 * we have to be careful that each branch has a unique size.
114 */
115 switch ((enum i915_gtt_view_type)0) {
116 case I915_GTT_VIEW_NORMAL:
117 case I915_GTT_VIEW_PARTIAL:
118 case I915_GTT_VIEW_ROTATED:
119 case I915_GTT_VIEW_REMAPPED:
120 /* gcc complains if these are identical cases */
121 break;
122 }
123}
124
125/**
126 * DOC: Virtual Memory Address
127 *
128 * A VMA represents a GEM BO that is bound into an address space. Therefore, a
129 * VMA's presence cannot be guaranteed before binding, or after unbinding the
130 * object into/from the address space.
131 *
132 * To make things as simple as possible (ie. no refcounting), a VMA's lifetime
133 * will always be <= an objects lifetime. So object refcounting should cover us.
134 */
135struct i915_vma {
136 struct drm_mm_node node;
137
138 struct i915_address_space *vm;
139 const struct i915_vma_ops *ops;
140
141 struct drm_i915_gem_object *obj;
142
143 struct sg_table *pages;
144 void __iomem *iomap;
145 void *private; /* owned by creator */
146
147 struct i915_fence_reg *fence;
148
149 u64 size;
150 struct i915_page_sizes page_sizes;
151
152 /* mmap-offset associated with fencing for this vma */
153 struct i915_mmap_offset *mmo;
154
155 u32 guard; /* padding allocated around vma->pages within the node */
156 u32 fence_size;
157 u32 fence_alignment;
158 u32 display_alignment;
159
160 /**
161 * Count of the number of times this vma has been opened by different
162 * handles (but same file) for execbuf, i.e. the number of aliases
163 * that exist in the ctx->handle_vmas LUT for this vma.
164 */
165 atomic_t open_count;
166 atomic_t flags;
167 /**
168 * How many users have pinned this object in GTT space.
169 *
170 * This is a tightly bound, fairly small number of users, so we
171 * stuff inside the flags field so that we can both check for overflow
172 * and detect a no-op i915_vma_pin() in a single check, while also
173 * pinning the vma.
174 *
175 * The worst case display setup would have the same vma pinned for
176 * use on each plane on each crtc, while also building the next atomic
177 * state and holding a pin for the length of the cleanup queue. In the
178 * future, the flip queue may be increased from 1.
179 * Estimated worst case: 3 [qlen] * 4 [max crtcs] * 7 [max planes] = 84
180 *
181 * For GEM, the number of concurrent users for pwrite/pread is
182 * unbounded. For execbuffer, it is currently one but will in future
183 * be extended to allow multiple clients to pin vma concurrently.
184 *
185 * We also use suballocated pages, with each suballocation claiming
186 * its own pin on the shared vma. At present, this is limited to
187 * exclusive cachelines of a single page, so a maximum of 64 possible
188 * users.
189 */
190#define I915_VMA_PIN_MASK 0x3ff
191#define I915_VMA_OVERFLOW 0x200
192
193 /** Flags and address space this VMA is bound to */
194#define I915_VMA_GLOBAL_BIND_BIT 10
195#define I915_VMA_LOCAL_BIND_BIT 11
196
197#define I915_VMA_GLOBAL_BIND ((int)BIT(I915_VMA_GLOBAL_BIND_BIT))
198#define I915_VMA_LOCAL_BIND ((int)BIT(I915_VMA_LOCAL_BIND_BIT))
199
200#define I915_VMA_BIND_MASK (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND)
201
202#define I915_VMA_ERROR_BIT 12
203#define I915_VMA_ERROR ((int)BIT(I915_VMA_ERROR_BIT))
204
205#define I915_VMA_GGTT_BIT 13
206#define I915_VMA_CAN_FENCE_BIT 14
207#define I915_VMA_USERFAULT_BIT 15
208#define I915_VMA_GGTT_WRITE_BIT 16
209
210#define I915_VMA_GGTT ((int)BIT(I915_VMA_GGTT_BIT))
211#define I915_VMA_CAN_FENCE ((int)BIT(I915_VMA_CAN_FENCE_BIT))
212#define I915_VMA_USERFAULT ((int)BIT(I915_VMA_USERFAULT_BIT))
213#define I915_VMA_GGTT_WRITE ((int)BIT(I915_VMA_GGTT_WRITE_BIT))
214
215#define I915_VMA_SCANOUT_BIT 17
216#define I915_VMA_SCANOUT ((int)BIT(I915_VMA_SCANOUT_BIT))
217
218 struct i915_active active;
219
220#define I915_VMA_PAGES_BIAS 24
221#define I915_VMA_PAGES_ACTIVE (BIT(24) | 1)
222 atomic_t pages_count; /* number of active binds to the pages */
223
224 /**
225 * Whether we hold a reference on the vm dma_resv lock to temporarily
226 * block vm freeing until the vma is destroyed.
227 * Protected by the vm mutex.
228 */
229 bool vm_ddestroy;
230
231 /**
232 * Support different GGTT views into the same object.
233 * This means there can be multiple VMA mappings per object and per VM.
234 * i915_gtt_view_type is used to distinguish between those entries.
235 * The default one of zero (I915_GTT_VIEW_NORMAL) is default and also
236 * assumed in GEM functions which take no ggtt view parameter.
237 */
238 struct i915_gtt_view gtt_view;
239
240 /** This object's place on the active/inactive lists */
241 struct list_head vm_link;
242
243 struct list_head obj_link; /* Link in the object's VMA list */
244 struct rb_node obj_node;
245
246 /** This vma's place in the eviction list */
247 struct list_head evict_link;
248
249 struct list_head closed_link;
250
251 /** The async vma resource. Protected by the vm_mutex */
252 struct i915_vma_resource *resource;
253};
254
255#endif
256

source code of linux/drivers/gpu/drm/i915/i915_vma_types.h