xref: /openbmc/linux/include/drm/drm_framebuffer.h (revision a44e4f3a)
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 	 * Atomic drivers should use drm_atomic_helper_dirtyfb() to implement
91 	 * this hook.
92 	 *
93 	 * RETURNS:
94 	 *
95 	 * 0 on success or a negative error code on failure.
96 	 */
97 	int (*dirty)(struct drm_framebuffer *framebuffer,
98 		     struct drm_file *file_priv, unsigned flags,
99 		     unsigned color, struct drm_clip_rect *clips,
100 		     unsigned num_clips);
101 };
102 
103 /**
104  * struct drm_framebuffer - frame buffer object
105  *
106  * Note that the fb is refcounted for the benefit of driver internals,
107  * for example some hw, disabling a CRTC/plane is asynchronous, and
108  * scanout does not actually complete until the next vblank.  So some
109  * cleanup (like releasing the reference(s) on the backing GEM bo(s))
110  * should be deferred.  In cases like this, the driver would like to
111  * hold a ref to the fb even though it has already been removed from
112  * userspace perspective. See drm_framebuffer_get() and
113  * drm_framebuffer_put().
114  *
115  * The refcount is stored inside the mode object @base.
116  */
117 struct drm_framebuffer {
118 	/**
119 	 * @dev: DRM device this framebuffer belongs to
120 	 */
121 	struct drm_device *dev;
122 	/**
123 	 * @head: Place on the &drm_mode_config.fb_list, access protected by
124 	 * &drm_mode_config.fb_lock.
125 	 */
126 	struct list_head head;
127 
128 	/**
129 	 * @base: base modeset object structure, contains the reference count.
130 	 */
131 	struct drm_mode_object base;
132 
133 	/**
134 	 * @comm: Name of the process allocating the fb, used for fb dumping.
135 	 */
136 	char comm[TASK_COMM_LEN];
137 
138 	/**
139 	 * @format: framebuffer format information
140 	 */
141 	const struct drm_format_info *format;
142 	/**
143 	 * @funcs: framebuffer vfunc table
144 	 */
145 	const struct drm_framebuffer_funcs *funcs;
146 	/**
147 	 * @pitches: Line stride per buffer. For userspace created object this
148 	 * is copied from drm_mode_fb_cmd2.
149 	 */
150 	unsigned int pitches[4];
151 	/**
152 	 * @offsets: Offset from buffer start to the actual pixel data in bytes,
153 	 * per buffer. For userspace created object this is copied from
154 	 * drm_mode_fb_cmd2.
155 	 *
156 	 * Note that this is a linear offset and does not take into account
157 	 * tiling or buffer laytou per @modifier. It meant to be used when the
158 	 * actual pixel data for this framebuffer plane starts at an offset,
159 	 * e.g.  when multiple planes are allocated within the same backing
160 	 * storage buffer object. For tiled layouts this generally means it
161 	 * @offsets must at least be tile-size aligned, but hardware often has
162 	 * stricter requirements.
163 	 *
164 	 * This should not be used to specifiy x/y pixel offsets into the buffer
165 	 * data (even for linear buffers). Specifying an x/y pixel offset is
166 	 * instead done through the source rectangle in &struct drm_plane_state.
167 	 */
168 	unsigned int offsets[4];
169 	/**
170 	 * @modifier: Data layout modifier. This is used to describe
171 	 * tiling, or also special layouts (like compression) of auxiliary
172 	 * buffers. For userspace created object this is copied from
173 	 * drm_mode_fb_cmd2.
174 	 */
175 	uint64_t modifier;
176 	/**
177 	 * @width: Logical width of the visible area of the framebuffer, in
178 	 * pixels.
179 	 */
180 	unsigned int width;
181 	/**
182 	 * @height: Logical height of the visible area of the framebuffer, in
183 	 * pixels.
184 	 */
185 	unsigned int height;
186 	/**
187 	 * @flags: Framebuffer flags like DRM_MODE_FB_INTERLACED or
188 	 * DRM_MODE_FB_MODIFIERS.
189 	 */
190 	int flags;
191 	/**
192 	 * @hot_x: X coordinate of the cursor hotspot. Used by the legacy cursor
193 	 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
194 	 * universal plane.
195 	 */
196 	int hot_x;
197 	/**
198 	 * @hot_y: Y coordinate of the cursor hotspot. Used by the legacy cursor
199 	 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
200 	 * universal plane.
201 	 */
202 	int hot_y;
203 	/**
204 	 * @filp_head: Placed on &drm_file.fbs, protected by &drm_file.fbs_lock.
205 	 */
206 	struct list_head filp_head;
207 	/**
208 	 * @obj: GEM objects backing the framebuffer, one per plane (optional).
209 	 *
210 	 * This is used by the GEM framebuffer helpers, see e.g.
211 	 * drm_gem_fb_create().
212 	 */
213 	struct drm_gem_object *obj[4];
214 };
215 
216 #define obj_to_fb(x) container_of(x, struct drm_framebuffer, base)
217 
218 int drm_framebuffer_init(struct drm_device *dev,
219 			 struct drm_framebuffer *fb,
220 			 const struct drm_framebuffer_funcs *funcs);
221 struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
222 					       struct drm_file *file_priv,
223 					       uint32_t id);
224 void drm_framebuffer_remove(struct drm_framebuffer *fb);
225 void drm_framebuffer_cleanup(struct drm_framebuffer *fb);
226 void drm_framebuffer_unregister_private(struct drm_framebuffer *fb);
227 
228 /**
229  * drm_framebuffer_get - acquire a framebuffer reference
230  * @fb: DRM framebuffer
231  *
232  * This function increments the framebuffer's reference count.
233  */
234 static inline void drm_framebuffer_get(struct drm_framebuffer *fb)
235 {
236 	drm_mode_object_get(&fb->base);
237 }
238 
239 /**
240  * drm_framebuffer_put - release a framebuffer reference
241  * @fb: DRM framebuffer
242  *
243  * This function decrements the framebuffer's reference count and frees the
244  * framebuffer if the reference count drops to zero.
245  */
246 static inline void drm_framebuffer_put(struct drm_framebuffer *fb)
247 {
248 	drm_mode_object_put(&fb->base);
249 }
250 
251 /**
252  * drm_framebuffer_read_refcount - read the framebuffer reference count.
253  * @fb: framebuffer
254  *
255  * This functions returns the framebuffer's reference count.
256  */
257 static inline uint32_t drm_framebuffer_read_refcount(const struct drm_framebuffer *fb)
258 {
259 	return kref_read(&fb->base.refcount);
260 }
261 
262 /**
263  * drm_framebuffer_assign - store a reference to the fb
264  * @p: location to store framebuffer
265  * @fb: new framebuffer (maybe NULL)
266  *
267  * This functions sets the location to store a reference to the framebuffer,
268  * unreferencing the framebuffer that was previously stored in that location.
269  */
270 static inline void drm_framebuffer_assign(struct drm_framebuffer **p,
271 					  struct drm_framebuffer *fb)
272 {
273 	if (fb)
274 		drm_framebuffer_get(fb);
275 	if (*p)
276 		drm_framebuffer_put(*p);
277 	*p = fb;
278 }
279 
280 /*
281  * drm_for_each_fb - iterate over all framebuffers
282  * @fb: the loop cursor
283  * @dev: the DRM device
284  *
285  * Iterate over all framebuffers of @dev. User must hold
286  * &drm_mode_config.fb_lock.
287  */
288 #define drm_for_each_fb(fb, dev) \
289 	for (WARN_ON(!mutex_is_locked(&(dev)->mode_config.fb_lock)),		\
290 	     fb = list_first_entry(&(dev)->mode_config.fb_list,	\
291 					  struct drm_framebuffer, head);	\
292 	     &fb->head != (&(dev)->mode_config.fb_list);			\
293 	     fb = list_next_entry(fb, head))
294 
295 int drm_framebuffer_plane_width(int width,
296 				const struct drm_framebuffer *fb, int plane);
297 int drm_framebuffer_plane_height(int height,
298 				 const struct drm_framebuffer *fb, int plane);
299 
300 #endif
301