Commit | Line | Data |
---|---|---|
fe3078fa DH |
1 | /* |
2 | * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA | |
3 | * Copyright (c) 2012 David Airlie <airlied@linux.ie> | |
4 | * Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.com> | |
5 | * | |
6 | * Permission is hereby granted, free of charge, to any person obtaining a | |
7 | * copy of this software and associated documentation files (the "Software"), | |
8 | * to deal in the Software without restriction, including without limitation | |
9 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
10 | * and/or sell copies of the Software, and to permit persons to whom the | |
11 | * Software is furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR | |
20 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, | |
21 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR | |
22 | * OTHER DEALINGS IN THE SOFTWARE. | |
23 | */ | |
24 | ||
25 | #include <drm/drmP.h> | |
26 | #include <drm/drm_mm.h> | |
27 | #include <drm/drm_vma_manager.h> | |
28 | #include <linux/mm.h> | |
29 | #include <linux/module.h> | |
30 | #include <linux/rbtree.h> | |
31 | #include <linux/slab.h> | |
32 | #include <linux/spinlock.h> | |
33 | #include <linux/types.h> | |
34 | ||
35 | /** | |
36 | * DOC: vma offset manager | |
37 | * | |
38 | * The vma-manager is responsible to map arbitrary driver-dependent memory | |
39 | * regions into the linear user address-space. It provides offsets to the | |
40 | * caller which can then be used on the address_space of the drm-device. It | |
41 | * takes care to not overlap regions, size them appropriately and to not | |
42 | * confuse mm-core by inconsistent fake vm_pgoff fields. | |
43 | * Drivers shouldn't use this for object placement in VMEM. This manager should | |
44 | * only be used to manage mappings into linear user-space VMs. | |
45 | * | |
46 | * We use drm_mm as backend to manage object allocations. But it is highly | |
47 | * optimized for alloc/free calls, not lookups. Hence, we use an rb-tree to | |
48 | * speed up offset lookups. | |
49 | * | |
50 | * You must not use multiple offset managers on a single address_space. | |
51 | * Otherwise, mm-core will be unable to tear down memory mappings as the VM will | |
52 | * no longer be linear. Please use VM_NONLINEAR in that case and implement your | |
53 | * own offset managers. | |
54 | * | |
55 | * This offset manager works on page-based addresses. That is, every argument | |
56 | * and return code (with the exception of drm_vma_node_offset_addr()) is given | |
57 | * in number of pages, not number of bytes. That means, object sizes and offsets | |
58 | * must always be page-aligned (as usual). | |
59 | * If you want to get a valid byte-based user-space address for a given offset, | |
60 | * please see drm_vma_node_offset_addr(). | |
61 | */ | |
62 | ||
63 | /** | |
64 | * drm_vma_offset_manager_init - Initialize new offset-manager | |
65 | * @mgr: Manager object | |
66 | * @page_offset: Offset of available memory area (page-based) | |
67 | * @size: Size of available address space range (page-based) | |
68 | * | |
69 | * Initialize a new offset-manager. The offset and area size available for the | |
70 | * manager are given as @page_offset and @size. Both are interpreted as | |
71 | * page-numbers, not bytes. | |
72 | * | |
73 | * Adding/removing nodes from the manager is locked internally and protected | |
74 | * against concurrent access. However, node allocation and destruction is left | |
75 | * for the caller. While calling into the vma-manager, a given node must | |
76 | * always be guaranteed to be referenced. | |
77 | */ | |
78 | void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr, | |
79 | unsigned long page_offset, unsigned long size) | |
80 | { | |
81 | rwlock_init(&mgr->vm_lock); | |
82 | mgr->vm_addr_space_rb = RB_ROOT; | |
83 | drm_mm_init(&mgr->vm_addr_space_mm, page_offset, size); | |
84 | } | |
85 | EXPORT_SYMBOL(drm_vma_offset_manager_init); | |
86 | ||
87 | /** | |
88 | * drm_vma_offset_manager_destroy() - Destroy offset manager | |
89 | * @mgr: Manager object | |
90 | * | |
91 | * Destroy an object manager which was previously created via | |
92 | * drm_vma_offset_manager_init(). The caller must remove all allocated nodes | |
93 | * before destroying the manager. Otherwise, drm_mm will refuse to free the | |
94 | * requested resources. | |
95 | * | |
96 | * The manager must not be accessed after this function is called. | |
97 | */ | |
98 | void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr) | |
99 | { | |
100 | /* take the lock to protect against buggy drivers */ | |
101 | write_lock(&mgr->vm_lock); | |
102 | drm_mm_takedown(&mgr->vm_addr_space_mm); | |
103 | write_unlock(&mgr->vm_lock); | |
104 | } | |
105 | EXPORT_SYMBOL(drm_vma_offset_manager_destroy); | |
106 | ||
107 | /** | |
108 | * drm_vma_offset_lookup() - Find node in offset space | |
109 | * @mgr: Manager object | |
110 | * @start: Start address for object (page-based) | |
111 | * @pages: Size of object (page-based) | |
112 | * | |
113 | * Find a node given a start address and object size. This returns the _best_ | |
114 | * match for the given node. That is, @start may point somewhere into a valid | |
115 | * region and the given node will be returned, as long as the node spans the | |
116 | * whole requested area (given the size in number of pages as @pages). | |
117 | * | |
118 | * RETURNS: | |
119 | * Returns NULL if no suitable node can be found. Otherwise, the best match | |
120 | * is returned. It's the caller's responsibility to make sure the node doesn't | |
121 | * get destroyed before the caller can access it. | |
122 | */ | |
123 | struct drm_vma_offset_node *drm_vma_offset_lookup(struct drm_vma_offset_manager *mgr, | |
124 | unsigned long start, | |
125 | unsigned long pages) | |
126 | { | |
127 | struct drm_vma_offset_node *node; | |
128 | ||
129 | read_lock(&mgr->vm_lock); | |
130 | node = drm_vma_offset_lookup_locked(mgr, start, pages); | |
131 | read_unlock(&mgr->vm_lock); | |
132 | ||
133 | return node; | |
134 | } | |
135 | EXPORT_SYMBOL(drm_vma_offset_lookup); | |
136 | ||
137 | /** | |
138 | * drm_vma_offset_lookup_locked() - Find node in offset space | |
139 | * @mgr: Manager object | |
140 | * @start: Start address for object (page-based) | |
141 | * @pages: Size of object (page-based) | |
142 | * | |
143 | * Same as drm_vma_offset_lookup() but requires the caller to lock offset lookup | |
144 | * manually. See drm_vma_offset_lock_lookup() for an example. | |
145 | * | |
146 | * RETURNS: | |
147 | * Returns NULL if no suitable node can be found. Otherwise, the best match | |
148 | * is returned. | |
149 | */ | |
150 | struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr, | |
151 | unsigned long start, | |
152 | unsigned long pages) | |
153 | { | |
154 | struct drm_vma_offset_node *node, *best; | |
155 | struct rb_node *iter; | |
156 | unsigned long offset; | |
157 | ||
158 | iter = mgr->vm_addr_space_rb.rb_node; | |
159 | best = NULL; | |
160 | ||
161 | while (likely(iter)) { | |
162 | node = rb_entry(iter, struct drm_vma_offset_node, vm_rb); | |
163 | offset = node->vm_node.start; | |
164 | if (start >= offset) { | |
165 | iter = iter->rb_right; | |
166 | best = node; | |
167 | if (start == offset) | |
168 | break; | |
169 | } else { | |
170 | iter = iter->rb_left; | |
171 | } | |
172 | } | |
173 | ||
174 | /* verify that the node spans the requested area */ | |
175 | if (best) { | |
176 | offset = best->vm_node.start + best->vm_node.size; | |
177 | if (offset < start + pages) | |
178 | best = NULL; | |
179 | } | |
180 | ||
181 | return best; | |
182 | } | |
183 | EXPORT_SYMBOL(drm_vma_offset_lookup_locked); | |
184 | ||
185 | /* internal helper to link @node into the rb-tree */ | |
186 | static void _drm_vma_offset_add_rb(struct drm_vma_offset_manager *mgr, | |
187 | struct drm_vma_offset_node *node) | |
188 | { | |
189 | struct rb_node **iter = &mgr->vm_addr_space_rb.rb_node; | |
190 | struct rb_node *parent = NULL; | |
191 | struct drm_vma_offset_node *iter_node; | |
192 | ||
193 | while (likely(*iter)) { | |
194 | parent = *iter; | |
195 | iter_node = rb_entry(*iter, struct drm_vma_offset_node, vm_rb); | |
196 | ||
197 | if (node->vm_node.start < iter_node->vm_node.start) | |
198 | iter = &(*iter)->rb_left; | |
199 | else if (node->vm_node.start > iter_node->vm_node.start) | |
200 | iter = &(*iter)->rb_right; | |
201 | else | |
202 | BUG(); | |
203 | } | |
204 | ||
205 | rb_link_node(&node->vm_rb, parent, iter); | |
206 | rb_insert_color(&node->vm_rb, &mgr->vm_addr_space_rb); | |
207 | } | |
208 | ||
209 | /** | |
210 | * drm_vma_offset_add() - Add offset node to manager | |
211 | * @mgr: Manager object | |
212 | * @node: Node to be added | |
213 | * @pages: Allocation size visible to user-space (in number of pages) | |
214 | * | |
215 | * Add a node to the offset-manager. If the node was already added, this does | |
216 | * nothing and return 0. @pages is the size of the object given in number of | |
217 | * pages. | |
218 | * After this call succeeds, you can access the offset of the node until it | |
219 | * is removed again. | |
220 | * | |
221 | * If this call fails, it is safe to retry the operation or call | |
222 | * drm_vma_offset_remove(), anyway. However, no cleanup is required in that | |
223 | * case. | |
224 | * | |
225 | * @pages is not required to be the same size as the underlying memory object | |
226 | * that you want to map. It only limits the size that user-space can map into | |
227 | * their address space. | |
228 | * | |
229 | * RETURNS: | |
230 | * 0 on success, negative error code on failure. | |
231 | */ | |
232 | int drm_vma_offset_add(struct drm_vma_offset_manager *mgr, | |
233 | struct drm_vma_offset_node *node, unsigned long pages) | |
234 | { | |
235 | int ret; | |
236 | ||
237 | write_lock(&mgr->vm_lock); | |
238 | ||
239 | if (drm_mm_node_allocated(&node->vm_node)) { | |
240 | ret = 0; | |
241 | goto out_unlock; | |
242 | } | |
243 | ||
31e5d7c6 DH |
244 | ret = drm_mm_insert_node(&mgr->vm_addr_space_mm, &node->vm_node, |
245 | pages, 0, DRM_MM_SEARCH_DEFAULT); | |
fe3078fa DH |
246 | if (ret) |
247 | goto out_unlock; | |
248 | ||
249 | _drm_vma_offset_add_rb(mgr, node); | |
250 | ||
251 | out_unlock: | |
252 | write_unlock(&mgr->vm_lock); | |
253 | return ret; | |
254 | } | |
255 | EXPORT_SYMBOL(drm_vma_offset_add); | |
256 | ||
257 | /** | |
258 | * drm_vma_offset_remove() - Remove offset node from manager | |
259 | * @mgr: Manager object | |
260 | * @node: Node to be removed | |
261 | * | |
262 | * Remove a node from the offset manager. If the node wasn't added before, this | |
263 | * does nothing. After this call returns, the offset and size will be 0 until a | |
264 | * new offset is allocated via drm_vma_offset_add() again. Helper functions like | |
265 | * drm_vma_node_start() and drm_vma_node_offset_addr() will return 0 if no | |
266 | * offset is allocated. | |
267 | */ | |
268 | void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr, | |
269 | struct drm_vma_offset_node *node) | |
270 | { | |
271 | write_lock(&mgr->vm_lock); | |
272 | ||
273 | if (drm_mm_node_allocated(&node->vm_node)) { | |
274 | rb_erase(&node->vm_rb, &mgr->vm_addr_space_rb); | |
275 | drm_mm_remove_node(&node->vm_node); | |
276 | memset(&node->vm_node, 0, sizeof(node->vm_node)); | |
277 | } | |
278 | ||
279 | write_unlock(&mgr->vm_lock); | |
280 | } | |
281 | EXPORT_SYMBOL(drm_vma_offset_remove); |