xref: /openbmc/linux/include/drm/drm_framebuffer.h (revision 62e59c4e)
1 /*
2  * Copyright (c) 2016 Intel Corporation
3  *
4  * Permission to use, copy, modify, distribute, and sell this software and its
5  * documentation for any purpose is hereby granted without fee, provided that
6  * the above copyright notice appear in all copies and that both that copyright
7  * notice and this permission notice appear in supporting documentation, and
8  * that the name of the copyright holders not be used in advertising or
9  * publicity pertaining to distribution of the software without specific,
10  * written prior permission.  The copyright holders make no representations
11  * about the suitability of this software for any purpose.  It is provided "as
12  * is" without express or implied warranty.
13  *
14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20  * OF THIS SOFTWARE.
21  */
22 
23 #ifndef __DRM_FRAMEBUFFER_H__
24 #define __DRM_FRAMEBUFFER_H__
25 
26 #include <linux/ctype.h>
27 #include <linux/list.h>
28 #include <linux/sched.h>
29 
30 #include <drm/drm_mode_object.h>
31 
32 struct drm_clip_rect;
33 struct drm_device;
34 struct drm_file;
35 struct drm_framebuffer;
36 struct drm_gem_object;
37 
38 /**
39  * struct drm_framebuffer_funcs - framebuffer hooks
40  */
41 struct drm_framebuffer_funcs {
42 	/**
43 	 * @destroy:
44 	 *
45 	 * Clean up framebuffer resources, specifically also unreference the
46 	 * backing storage. The core guarantees to call this function for every
47 	 * framebuffer successfully created by calling
48 	 * &drm_mode_config_funcs.fb_create. Drivers must also call
49 	 * drm_framebuffer_cleanup() to release DRM core resources for this
50 	 * framebuffer.
51 	 */
52 	void (*destroy)(struct drm_framebuffer *framebuffer);
53 
54 	/**
55 	 * @create_handle:
56 	 *
57 	 * Create a buffer handle in the driver-specific buffer manager (either
58 	 * GEM or TTM) valid for the passed-in &struct drm_file. This is used by
59 	 * the core to implement the GETFB IOCTL, which returns (for
60 	 * sufficiently priviledged user) also a native buffer handle. This can
61 	 * be used for seamless transitions between modesetting clients by
62 	 * copying the current screen contents to a private buffer and blending
63 	 * between that and the new contents.
64 	 *
65 	 * GEM based drivers should call drm_gem_handle_create() to create the
66 	 * handle.
67 	 *
68 	 * RETURNS:
69 	 *
70 	 * 0 on success or a negative error code on failure.
71 	 */
72 	int (*create_handle)(struct drm_framebuffer *fb,
73 			     struct drm_file *file_priv,
74 			     unsigned int *handle);
75 	/**
76 	 * @dirty:
77 	 *
78 	 * Optional callback for the dirty fb IOCTL.
79 	 *
80 	 * Userspace can notify the driver via this callback that an area of the
81 	 * framebuffer has changed and should be flushed to the display
82 	 * hardware. This can also be used internally, e.g. by the fbdev
83 	 * emulation, though that's not the case currently.
84 	 *
85 	 * See documentation in drm_mode.h for the struct drm_mode_fb_dirty_cmd
86 	 * for more information as all the semantics and arguments have a one to
87 	 * one mapping on this function.
88 	 *
89 	 * RETURNS:
90 	 *
91 	 * 0 on success or a negative error code on failure.
92 	 */
93 	int (*dirty)(struct drm_framebuffer *framebuffer,
94 		     struct drm_file *file_priv, unsigned flags,
95 		     unsigned color, struct drm_clip_rect *clips,
96 		     unsigned num_clips);
97 };
98 
99 /**
100  * struct drm_framebuffer - frame buffer object
101  *
102  * Note that the fb is refcounted for the benefit of driver internals,
103  * for example some hw, disabling a CRTC/plane is asynchronous, and
104  * scanout does not actually complete until the next vblank.  So some
105  * cleanup (like releasing the reference(s) on the backing GEM bo(s))
106  * should be deferred.  In cases like this, the driver would like to
107  * hold a ref to the fb even though it has already been removed from
108  * userspace perspective. See drm_framebuffer_get() and
109  * drm_framebuffer_put().
110  *
111  * The refcount is stored inside the mode object @base.
112  */
113 struct drm_framebuffer {
114 	/**
115 	 * @dev: DRM device this framebuffer belongs to
116 	 */
117 	struct drm_device *dev;
118 	/**
119 	 * @head: Place on the &drm_mode_config.fb_list, access protected by
120 	 * &drm_mode_config.fb_lock.
121 	 */
122 	struct list_head head;
123 
124 	/**
125 	 * @base: base modeset object structure, contains the reference count.
126 	 */
127 	struct drm_mode_object base;
128 
129 	/**
130 	 * @comm: Name of the process allocating the fb, used for fb dumping.
131 	 */
132 	char comm[TASK_COMM_LEN];
133 
134 	/**
135 	 * @format: framebuffer format information
136 	 */
137 	const struct drm_format_info *format;
138 	/**
139 	 * @funcs: framebuffer vfunc table
140 	 */
141 	const struct drm_framebuffer_funcs *funcs;
142 	/**
143 	 * @pitches: Line stride per buffer. For userspace created object this
144 	 * is copied from drm_mode_fb_cmd2.
145 	 */
146 	unsigned int pitches[4];
147 	/**
148 	 * @offsets: Offset from buffer start to the actual pixel data in bytes,
149 	 * per buffer. For userspace created object this is copied from
150 	 * drm_mode_fb_cmd2.
151 	 *
152 	 * Note that this is a linear offset and does not take into account
153 	 * tiling or buffer laytou per @modifier. It meant to be used when the
154 	 * actual pixel data for this framebuffer plane starts at an offset,
155 	 * e.g.  when multiple planes are allocated within the same backing
156 	 * storage buffer object. For tiled layouts this generally means it
157 	 * @offsets must at least be tile-size aligned, but hardware often has
158 	 * stricter requirements.
159 	 *
160 	 * This should not be used to specifiy x/y pixel offsets into the buffer
161 	 * data (even for linear buffers). Specifying an x/y pixel offset is
162 	 * instead done through the source rectangle in &struct drm_plane_state.
163 	 */
164 	unsigned int offsets[4];
165 	/**
166 	 * @modifier: Data layout modifier. This is used to describe
167 	 * tiling, or also special layouts (like compression) of auxiliary
168 	 * buffers. For userspace created object this is copied from
169 	 * drm_mode_fb_cmd2.
170 	 */
171 	uint64_t modifier;
172 	/**
173 	 * @width: Logical width of the visible area of the framebuffer, in
174 	 * pixels.
175 	 */
176 	unsigned int width;
177 	/**
178 	 * @height: Logical height of the visible area of the framebuffer, in
179 	 * pixels.
180 	 */
181 	unsigned int height;
182 	/**
183 	 * @flags: Framebuffer flags like DRM_MODE_FB_INTERLACED or
184 	 * DRM_MODE_FB_MODIFIERS.
185 	 */
186 	int flags;
187 	/**
188 	 * @hot_x: X coordinate of the cursor hotspot. Used by the legacy cursor
189 	 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
190 	 * universal plane.
191 	 */
192 	int hot_x;
193 	/**
194 	 * @hot_y: Y coordinate of the cursor hotspot. Used by the legacy cursor
195 	 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
196 	 * universal plane.
197 	 */
198 	int hot_y;
199 	/**
200 	 * @filp_head: Placed on &drm_file.fbs, protected by &drm_file.fbs_lock.
201 	 */
202 	struct list_head filp_head;
203 	/**
204 	 * @obj: GEM objects backing the framebuffer, one per plane (optional).
205 	 *
206 	 * This is used by the GEM framebuffer helpers, see e.g.
207 	 * drm_gem_fb_create().
208 	 */
209 	struct drm_gem_object *obj[4];
210 };
211 
212 #define obj_to_fb(x) container_of(x, struct drm_framebuffer, base)
213 
214 int drm_framebuffer_init(struct drm_device *dev,
215 			 struct drm_framebuffer *fb,
216 			 const struct drm_framebuffer_funcs *funcs);
217 struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
218 					       struct drm_file *file_priv,
219 					       uint32_t id);
220 void drm_framebuffer_remove(struct drm_framebuffer *fb);
221 void drm_framebuffer_cleanup(struct drm_framebuffer *fb);
222 void drm_framebuffer_unregister_private(struct drm_framebuffer *fb);
223 
224 /**
225  * drm_framebuffer_get - acquire a framebuffer reference
226  * @fb: DRM framebuffer
227  *
228  * This function increments the framebuffer's reference count.
229  */
230 static inline void drm_framebuffer_get(struct drm_framebuffer *fb)
231 {
232 	drm_mode_object_get(&fb->base);
233 }
234 
235 /**
236  * drm_framebuffer_put - release a framebuffer reference
237  * @fb: DRM framebuffer
238  *
239  * This function decrements the framebuffer's reference count and frees the
240  * framebuffer if the reference count drops to zero.
241  */
242 static inline void drm_framebuffer_put(struct drm_framebuffer *fb)
243 {
244 	drm_mode_object_put(&fb->base);
245 }
246 
247 /**
248  * drm_framebuffer_read_refcount - read the framebuffer reference count.
249  * @fb: framebuffer
250  *
251  * This functions returns the framebuffer's reference count.
252  */
253 static inline uint32_t drm_framebuffer_read_refcount(const struct drm_framebuffer *fb)
254 {
255 	return kref_read(&fb->base.refcount);
256 }
257 
258 /**
259  * drm_framebuffer_assign - store a reference to the fb
260  * @p: location to store framebuffer
261  * @fb: new framebuffer (maybe NULL)
262  *
263  * This functions sets the location to store a reference to the framebuffer,
264  * unreferencing the framebuffer that was previously stored in that location.
265  */
266 static inline void drm_framebuffer_assign(struct drm_framebuffer **p,
267 					  struct drm_framebuffer *fb)
268 {
269 	if (fb)
270 		drm_framebuffer_get(fb);
271 	if (*p)
272 		drm_framebuffer_put(*p);
273 	*p = fb;
274 }
275 
276 /*
277  * drm_for_each_fb - iterate over all framebuffers
278  * @fb: the loop cursor
279  * @dev: the DRM device
280  *
281  * Iterate over all framebuffers of @dev. User must hold
282  * &drm_mode_config.fb_lock.
283  */
284 #define drm_for_each_fb(fb, dev) \
285 	for (WARN_ON(!mutex_is_locked(&(dev)->mode_config.fb_lock)),		\
286 	     fb = list_first_entry(&(dev)->mode_config.fb_list,	\
287 					  struct drm_framebuffer, head);	\
288 	     &fb->head != (&(dev)->mode_config.fb_list);			\
289 	     fb = list_next_entry(fb, head))
290 
291 int drm_framebuffer_plane_width(int width,
292 				const struct drm_framebuffer *fb, int plane);
293 int drm_framebuffer_plane_height(int height,
294 				 const struct drm_framebuffer *fb, int plane);
295 
296 #endif
297