xref: /openbmc/linux/include/drm/drm_framebuffer.h (revision 752beb5e)
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_format_info;
36 struct drm_framebuffer;
37 struct drm_gem_object;
38 
39 /**
40  * struct drm_framebuffer_funcs - framebuffer hooks
41  */
42 struct drm_framebuffer_funcs {
43 	/**
44 	 * @destroy:
45 	 *
46 	 * Clean up framebuffer resources, specifically also unreference the
47 	 * backing storage. The core guarantees to call this function for every
48 	 * framebuffer successfully created by calling
49 	 * &drm_mode_config_funcs.fb_create. Drivers must also call
50 	 * drm_framebuffer_cleanup() to release DRM core resources for this
51 	 * framebuffer.
52 	 */
53 	void (*destroy)(struct drm_framebuffer *framebuffer);
54 
55 	/**
56 	 * @create_handle:
57 	 *
58 	 * Create a buffer handle in the driver-specific buffer manager (either
59 	 * GEM or TTM) valid for the passed-in &struct drm_file. This is used by
60 	 * the core to implement the GETFB IOCTL, which returns (for
61 	 * sufficiently priviledged user) also a native buffer handle. This can
62 	 * be used for seamless transitions between modesetting clients by
63 	 * copying the current screen contents to a private buffer and blending
64 	 * between that and the new contents.
65 	 *
66 	 * GEM based drivers should call drm_gem_handle_create() to create the
67 	 * handle.
68 	 *
69 	 * RETURNS:
70 	 *
71 	 * 0 on success or a negative error code on failure.
72 	 */
73 	int (*create_handle)(struct drm_framebuffer *fb,
74 			     struct drm_file *file_priv,
75 			     unsigned int *handle);
76 	/**
77 	 * @dirty:
78 	 *
79 	 * Optional callback for the dirty fb IOCTL.
80 	 *
81 	 * Userspace can notify the driver via this callback that an area of the
82 	 * framebuffer has changed and should be flushed to the display
83 	 * hardware. This can also be used internally, e.g. by the fbdev
84 	 * emulation, though that's not the case currently.
85 	 *
86 	 * See documentation in drm_mode.h for the struct drm_mode_fb_dirty_cmd
87 	 * for more information as all the semantics and arguments have a one to
88 	 * one mapping on this function.
89 	 *
90 	 * RETURNS:
91 	 *
92 	 * 0 on success or a negative error code on failure.
93 	 */
94 	int (*dirty)(struct drm_framebuffer *framebuffer,
95 		     struct drm_file *file_priv, unsigned flags,
96 		     unsigned color, struct drm_clip_rect *clips,
97 		     unsigned num_clips);
98 };
99 
100 /**
101  * struct drm_framebuffer - frame buffer object
102  *
103  * Note that the fb is refcounted for the benefit of driver internals,
104  * for example some hw, disabling a CRTC/plane is asynchronous, and
105  * scanout does not actually complete until the next vblank.  So some
106  * cleanup (like releasing the reference(s) on the backing GEM bo(s))
107  * should be deferred.  In cases like this, the driver would like to
108  * hold a ref to the fb even though it has already been removed from
109  * userspace perspective. See drm_framebuffer_get() and
110  * drm_framebuffer_put().
111  *
112  * The refcount is stored inside the mode object @base.
113  */
114 struct drm_framebuffer {
115 	/**
116 	 * @dev: DRM device this framebuffer belongs to
117 	 */
118 	struct drm_device *dev;
119 	/**
120 	 * @head: Place on the &drm_mode_config.fb_list, access protected by
121 	 * &drm_mode_config.fb_lock.
122 	 */
123 	struct list_head head;
124 
125 	/**
126 	 * @base: base modeset object structure, contains the reference count.
127 	 */
128 	struct drm_mode_object base;
129 
130 	/**
131 	 * @comm: Name of the process allocating the fb, used for fb dumping.
132 	 */
133 	char comm[TASK_COMM_LEN];
134 
135 	/**
136 	 * @format: framebuffer format information
137 	 */
138 	const struct drm_format_info *format;
139 	/**
140 	 * @funcs: framebuffer vfunc table
141 	 */
142 	const struct drm_framebuffer_funcs *funcs;
143 	/**
144 	 * @pitches: Line stride per buffer. For userspace created object this
145 	 * is copied from drm_mode_fb_cmd2.
146 	 */
147 	unsigned int pitches[4];
148 	/**
149 	 * @offsets: Offset from buffer start to the actual pixel data in bytes,
150 	 * per buffer. For userspace created object this is copied from
151 	 * drm_mode_fb_cmd2.
152 	 *
153 	 * Note that this is a linear offset and does not take into account
154 	 * tiling or buffer laytou per @modifier. It meant to be used when the
155 	 * actual pixel data for this framebuffer plane starts at an offset,
156 	 * e.g.  when multiple planes are allocated within the same backing
157 	 * storage buffer object. For tiled layouts this generally means it
158 	 * @offsets must at least be tile-size aligned, but hardware often has
159 	 * stricter requirements.
160 	 *
161 	 * This should not be used to specifiy x/y pixel offsets into the buffer
162 	 * data (even for linear buffers). Specifying an x/y pixel offset is
163 	 * instead done through the source rectangle in &struct drm_plane_state.
164 	 */
165 	unsigned int offsets[4];
166 	/**
167 	 * @modifier: Data layout modifier. This is used to describe
168 	 * tiling, or also special layouts (like compression) of auxiliary
169 	 * buffers. For userspace created object this is copied from
170 	 * drm_mode_fb_cmd2.
171 	 */
172 	uint64_t modifier;
173 	/**
174 	 * @width: Logical width of the visible area of the framebuffer, in
175 	 * pixels.
176 	 */
177 	unsigned int width;
178 	/**
179 	 * @height: Logical height of the visible area of the framebuffer, in
180 	 * pixels.
181 	 */
182 	unsigned int height;
183 	/**
184 	 * @flags: Framebuffer flags like DRM_MODE_FB_INTERLACED or
185 	 * DRM_MODE_FB_MODIFIERS.
186 	 */
187 	int flags;
188 	/**
189 	 * @hot_x: X coordinate of the cursor hotspot. Used by the legacy cursor
190 	 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
191 	 * universal plane.
192 	 */
193 	int hot_x;
194 	/**
195 	 * @hot_y: Y coordinate of the cursor hotspot. Used by the legacy cursor
196 	 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
197 	 * universal plane.
198 	 */
199 	int hot_y;
200 	/**
201 	 * @filp_head: Placed on &drm_file.fbs, protected by &drm_file.fbs_lock.
202 	 */
203 	struct list_head filp_head;
204 	/**
205 	 * @obj: GEM objects backing the framebuffer, one per plane (optional).
206 	 *
207 	 * This is used by the GEM framebuffer helpers, see e.g.
208 	 * drm_gem_fb_create().
209 	 */
210 	struct drm_gem_object *obj[4];
211 };
212 
213 #define obj_to_fb(x) container_of(x, struct drm_framebuffer, base)
214 
215 int drm_framebuffer_init(struct drm_device *dev,
216 			 struct drm_framebuffer *fb,
217 			 const struct drm_framebuffer_funcs *funcs);
218 struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
219 					       struct drm_file *file_priv,
220 					       uint32_t id);
221 void drm_framebuffer_remove(struct drm_framebuffer *fb);
222 void drm_framebuffer_cleanup(struct drm_framebuffer *fb);
223 void drm_framebuffer_unregister_private(struct drm_framebuffer *fb);
224 
225 /**
226  * drm_framebuffer_get - acquire a framebuffer reference
227  * @fb: DRM framebuffer
228  *
229  * This function increments the framebuffer's reference count.
230  */
231 static inline void drm_framebuffer_get(struct drm_framebuffer *fb)
232 {
233 	drm_mode_object_get(&fb->base);
234 }
235 
236 /**
237  * drm_framebuffer_put - release a framebuffer reference
238  * @fb: DRM framebuffer
239  *
240  * This function decrements the framebuffer's reference count and frees the
241  * framebuffer if the reference count drops to zero.
242  */
243 static inline void drm_framebuffer_put(struct drm_framebuffer *fb)
244 {
245 	drm_mode_object_put(&fb->base);
246 }
247 
248 /**
249  * drm_framebuffer_read_refcount - read the framebuffer reference count.
250  * @fb: framebuffer
251  *
252  * This functions returns the framebuffer's reference count.
253  */
254 static inline uint32_t drm_framebuffer_read_refcount(const struct drm_framebuffer *fb)
255 {
256 	return kref_read(&fb->base.refcount);
257 }
258 
259 /**
260  * drm_framebuffer_assign - store a reference to the fb
261  * @p: location to store framebuffer
262  * @fb: new framebuffer (maybe NULL)
263  *
264  * This functions sets the location to store a reference to the framebuffer,
265  * unreferencing the framebuffer that was previously stored in that location.
266  */
267 static inline void drm_framebuffer_assign(struct drm_framebuffer **p,
268 					  struct drm_framebuffer *fb)
269 {
270 	if (fb)
271 		drm_framebuffer_get(fb);
272 	if (*p)
273 		drm_framebuffer_put(*p);
274 	*p = fb;
275 }
276 
277 /*
278  * drm_for_each_fb - iterate over all framebuffers
279  * @fb: the loop cursor
280  * @dev: the DRM device
281  *
282  * Iterate over all framebuffers of @dev. User must hold
283  * &drm_mode_config.fb_lock.
284  */
285 #define drm_for_each_fb(fb, dev) \
286 	for (WARN_ON(!mutex_is_locked(&(dev)->mode_config.fb_lock)),		\
287 	     fb = list_first_entry(&(dev)->mode_config.fb_list,	\
288 					  struct drm_framebuffer, head);	\
289 	     &fb->head != (&(dev)->mode_config.fb_list);			\
290 	     fb = list_next_entry(fb, head))
291 
292 int drm_framebuffer_plane_width(int width,
293 				const struct drm_framebuffer *fb, int plane);
294 int drm_framebuffer_plane_height(int height,
295 				 const struct drm_framebuffer *fb, int plane);
296 
297 #endif
298