i915_vma_types.h

  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"),
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  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
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 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