summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/drm_gem_framebuffer_helper.c
blob: 2810d413141182e4b6298524612670aa34a54757 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
/*
 * drm gem framebuffer helper functions
 *
 * Copyright (C) 2017 Noralf Trønnes
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/dma-buf.h>
#include <linux/dma-fence.h>
#include <linux/reservation.h>
#include <linux/slab.h>

#include <drm/drmP.h>
#include <drm/drm_atomic.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_modeset_helper.h>
#include <drm/drm_simple_kms_helper.h>

/**
 * DOC: overview
 *
 * This library provides helpers for drivers that don't subclass
 * &drm_framebuffer and use &drm_gem_object for their backing storage.
 *
 * Drivers without additional needs to validate framebuffers can simply use
 * drm_gem_fb_create() and everything is wired up automatically. Other drivers
 * can use all parts independently.
 */

/**
 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer
 * @fb: Framebuffer
 * @plane: Plane index
 *
 * No additional reference is taken beyond the one that the &drm_frambuffer
 * already holds.
 *
 * Returns:
 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL
 * if it does not exist.
 */
struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
					  unsigned int plane)
{
	if (plane >= 4)
		return NULL;

	return fb->obj[plane];
}
EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);

static struct drm_framebuffer *
drm_gem_fb_alloc(struct drm_device *dev,
		 const struct drm_mode_fb_cmd2 *mode_cmd,
		 struct drm_gem_object **obj, unsigned int num_planes,
		 const struct drm_framebuffer_funcs *funcs)
{
	struct drm_framebuffer *fb;
	int ret, i;

	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
	if (!fb)
		return ERR_PTR(-ENOMEM);

	drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);

	for (i = 0; i < num_planes; i++)
		fb->obj[i] = obj[i];

	ret = drm_framebuffer_init(dev, fb, funcs);
	if (ret) {
		DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n",
			      ret);
		kfree(fb);
		return ERR_PTR(ret);
	}

	return fb;
}

/**
 * drm_gem_fb_destroy - Free GEM backed framebuffer
 * @fb: Framebuffer
 *
 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure
 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
 * callback.
 */
void drm_gem_fb_destroy(struct drm_framebuffer *fb)
{
	int i;

	for (i = 0; i < 4; i++)
		drm_gem_object_put_unlocked(fb->obj[i]);

	drm_framebuffer_cleanup(fb);
	kfree(fb);
}
EXPORT_SYMBOL(drm_gem_fb_destroy);

/**
 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
 * @fb: Framebuffer
 * @file: DRM file to register the handle for
 * @handle: Pointer to return the created handle
 *
 * This function creates a handle for the GEM object backing the framebuffer.
 * Drivers can use this as their &drm_framebuffer_funcs->create_handle
 * callback. The GETFB IOCTL calls into this callback.
 *
 * Returns:
 * 0 on success or a negative error code on failure.
 */
int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
			     unsigned int *handle)
{
	return drm_gem_handle_create(file, fb->obj[0], handle);
}
EXPORT_SYMBOL(drm_gem_fb_create_handle);

/**
 * drm_gem_fb_create_with_funcs() - Helper function for the
 *                                  &drm_mode_config_funcs.fb_create
 *                                  callback
 * @dev: DRM device
 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
 * @mode_cmd: Metadata from the userspace framebuffer creation request
 * @funcs: vtable to be used for the new framebuffer object
 *
 * This can be used to set &drm_framebuffer_funcs for drivers that need the
 * &drm_framebuffer_funcs.dirty callback. Use drm_gem_fb_create() if you don't
 * need to change &drm_framebuffer_funcs.
 * The function does buffer size validation.
 *
 * Returns:
 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
 */
struct drm_framebuffer *
drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
			     const struct drm_mode_fb_cmd2 *mode_cmd,
			     const struct drm_framebuffer_funcs *funcs)
{
	const struct drm_format_info *info;
	struct drm_gem_object *objs[4];
	struct drm_framebuffer *fb;
	int ret, i;

	info = drm_get_format_info(dev, mode_cmd);
	if (!info)
		return ERR_PTR(-EINVAL);

	for (i = 0; i < info->num_planes; i++) {
		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
		unsigned int min_size;

		objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
		if (!objs[i]) {
			DRM_DEBUG_KMS("Failed to lookup GEM object\n");
			ret = -ENOENT;
			goto err_gem_object_put;
		}

		min_size = (height - 1) * mode_cmd->pitches[i]
			 + width * info->cpp[i]
			 + mode_cmd->offsets[i];

		if (objs[i]->size < min_size) {
			drm_gem_object_put_unlocked(objs[i]);
			ret = -EINVAL;
			goto err_gem_object_put;
		}
	}

	fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs);
	if (IS_ERR(fb)) {
		ret = PTR_ERR(fb);
		goto err_gem_object_put;
	}

	return fb;

err_gem_object_put:
	for (i--; i >= 0; i--)
		drm_gem_object_put_unlocked(objs[i]);

	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);

static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
	.destroy	= drm_gem_fb_destroy,
	.create_handle	= drm_gem_fb_create_handle,
};

/**
 * drm_gem_fb_create() - Helper function for the
 *                       &drm_mode_config_funcs.fb_create callback
 * @dev: DRM device
 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
 * @mode_cmd: Metadata from the userspace framebuffer creation request
 *
 * This function creates a new framebuffer object described by
 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
 * backing the framebuffer.
 *
 * If your hardware has special alignment or pitch requirements these should be
 * checked before calling this function. The function does buffer size
 * validation. Use drm_gem_fb_create_with_funcs() if you need to set
 * &drm_framebuffer_funcs.dirty.
 *
 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
 * The ADDFB2 IOCTL calls into this callback.
 *
 * Returns:
 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
 */
struct drm_framebuffer *
drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
		  const struct drm_mode_fb_cmd2 *mode_cmd)
{
	return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
					    &drm_gem_fb_funcs);
}
EXPORT_SYMBOL_GPL(drm_gem_fb_create);

/**
 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer
 * @plane: Plane
 * @state: Plane state the fence will be attached to
 *
 * This function prepares a GEM backed framebuffer for scanout by checking if
 * the plane framebuffer has a DMA-BUF attached. If it does, it extracts the
 * exclusive fence and attaches it to the plane state for the atomic helper to
 * wait on. This function can be used as the &drm_plane_helper_funcs.prepare_fb
 * callback.
 *
 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
 * gem based framebuffer drivers which have their buffers always pinned in
 * memory.
 */
int drm_gem_fb_prepare_fb(struct drm_plane *plane,
			  struct drm_plane_state *state)
{
	struct dma_buf *dma_buf;
	struct dma_fence *fence;

	if (!state->fb)
		return 0;

	dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf;
	if (dma_buf) {
		fence = reservation_object_get_excl_rcu(dma_buf->resv);
		drm_atomic_set_fence_for_plane(state, fence);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);

/**
 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for
 *     &drm_simple_display_pipe
 * @pipe: Simple display pipe
 * @plane_state: Plane state
 *
 * This function uses drm_gem_fb_prepare_fb() to check if the plane FB has a
 * &dma_buf attached, extracts the exclusive fence and attaches it to plane
 * state for the atomic helper to wait on. Drivers can use this as their
 * &drm_simple_display_pipe_funcs.prepare_fb callback.
 */
int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,
					      struct drm_plane_state *plane_state)
{
	return drm_gem_fb_prepare_fb(&pipe->plane, plane_state);
}
EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb);

/**
 * drm_gem_fbdev_fb_create - Create a GEM backed &drm_framebuffer for fbdev
 *                           emulation
 * @dev: DRM device
 * @sizes: fbdev size description
 * @pitch_align: Optional pitch alignment
 * @obj: GEM object backing the framebuffer
 * @funcs: Optional vtable to be used for the new framebuffer object when the
 *         dirty callback is needed.
 *
 * This function creates a framebuffer from a &drm_fb_helper_surface_size
 * description for use in the &drm_fb_helper_funcs.fb_probe callback.
 *
 * Returns:
 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
 */
struct drm_framebuffer *
drm_gem_fbdev_fb_create(struct drm_device *dev,
			struct drm_fb_helper_surface_size *sizes,
			unsigned int pitch_align, struct drm_gem_object *obj,
			const struct drm_framebuffer_funcs *funcs)
{
	struct drm_mode_fb_cmd2 mode_cmd = { 0 };

	mode_cmd.width = sizes->surface_width;
	mode_cmd.height = sizes->surface_height;
	mode_cmd.pitches[0] = sizes->surface_width *
			      DIV_ROUND_UP(sizes->surface_bpp, 8);
	if (pitch_align)
		mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0],
					      pitch_align);
	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
							sizes->surface_depth);
	if (obj->size < mode_cmd.pitches[0] * mode_cmd.height)
		return ERR_PTR(-EINVAL);

	if (!funcs)
		funcs = &drm_gem_fb_funcs;

	return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs);
}
EXPORT_SYMBOL(drm_gem_fbdev_fb_create);