1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * drm gem framebuffer helper functions
  4 *
  5 * Copyright (C) 2017 Noralf Trønnes
  6 */
  7
  8#include <linux/slab.h>
  9
 10#include <drm/drm_damage_helper.h>
 11#include <drm/drm_fb_helper.h>
 12#include <drm/drm_fourcc.h>
 13#include <drm/drm_framebuffer.h>
 14#include <drm/drm_gem.h>
 15#include <drm/drm_gem_framebuffer_helper.h>
 16#include <drm/drm_modeset_helper.h>
 17
 18#define AFBC_HEADER_SIZE		16
 19#define AFBC_TH_LAYOUT_ALIGNMENT	8
 20#define AFBC_HDR_ALIGN			64
 21#define AFBC_SUPERBLOCK_PIXELS		256
 22#define AFBC_SUPERBLOCK_ALIGNMENT	128
 23#define AFBC_TH_BODY_START_ALIGNMENT	4096
 24
 25/**
 26 * DOC: overview
 27 *
 28 * This library provides helpers for drivers that don't subclass
 29 * &drm_framebuffer and use &drm_gem_object for their backing storage.
 30 *
 31 * Drivers without additional needs to validate framebuffers can simply use
 32 * drm_gem_fb_create() and everything is wired up automatically. Other drivers
 33 * can use all parts independently.
 34 */
 35
 36/**
 37 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer
 38 * @fb: Framebuffer
 39 * @plane: Plane index
 40 *
 41 * No additional reference is taken beyond the one that the &drm_frambuffer
 42 * already holds.
 43 *
 44 * Returns:
 45 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL
 46 * if it does not exist.
 47 */
 48struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
 49					  unsigned int plane)
 50{
 51	if (plane >= 4)
 52		return NULL;
 53
 54	return fb->obj[plane];
 55}
 56EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
 57
 58static int
 59drm_gem_fb_init(struct drm_device *dev,
 60		 struct drm_framebuffer *fb,
 61		 const struct drm_mode_fb_cmd2 *mode_cmd,
 62		 struct drm_gem_object **obj, unsigned int num_planes,
 63		 const struct drm_framebuffer_funcs *funcs)
 64{
 65	int ret, i;
 66
 67	drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
 68
 69	for (i = 0; i < num_planes; i++)
 70		fb->obj[i] = obj[i];
 71
 72	ret = drm_framebuffer_init(dev, fb, funcs);
 73	if (ret)
 74		drm_err(dev, "Failed to init framebuffer: %d\n", ret);
 75
 76	return ret;
 77}
 78
 79/**
 80 * drm_gem_fb_destroy - Free GEM backed framebuffer
 81 * @fb: Framebuffer
 82 *
 83 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure
 84 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
 85 * callback.
 86 */
 87void drm_gem_fb_destroy(struct drm_framebuffer *fb)
 88{
 89	int i;
 90
 91	for (i = 0; i < 4; i++)
 92		drm_gem_object_put(fb->obj[i]);
 93
 94	drm_framebuffer_cleanup(fb);
 95	kfree(fb);
 96}
 97EXPORT_SYMBOL(drm_gem_fb_destroy);
 98
 99/**
100 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
101 * @fb: Framebuffer
102 * @file: DRM file to register the handle for
103 * @handle: Pointer to return the created handle
104 *
105 * This function creates a handle for the GEM object backing the framebuffer.
106 * Drivers can use this as their &drm_framebuffer_funcs->create_handle
107 * callback. The GETFB IOCTL calls into this callback.
108 *
109 * Returns:
110 * 0 on success or a negative error code on failure.
111 */
112int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
113			     unsigned int *handle)
114{
115	return drm_gem_handle_create(file, fb->obj[0], handle);
116}
117EXPORT_SYMBOL(drm_gem_fb_create_handle);
118
119/**
120 * drm_gem_fb_init_with_funcs() - Helper function for implementing
121 *				  &drm_mode_config_funcs.fb_create
122 *				  callback in cases when the driver
123 *				  allocates a subclass of
124 *				  struct drm_framebuffer
125 * @dev: DRM device
126 * @fb: framebuffer object
127 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
128 * @mode_cmd: Metadata from the userspace framebuffer creation request
129 * @funcs: vtable to be used for the new framebuffer object
130 *
131 * This function can be used to set &drm_framebuffer_funcs for drivers that need
132 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to
133 * change &drm_framebuffer_funcs. The function does buffer size validation.
134 * The buffer size validation is for a general case, though, so users should
135 * pay attention to the checks being appropriate for them or, at least,
136 * non-conflicting.
137 *
138 * Returns:
139 * Zero or a negative error code.
140 */
141int drm_gem_fb_init_with_funcs(struct drm_device *dev,
142			       struct drm_framebuffer *fb,
143			       struct drm_file *file,
144			       const struct drm_mode_fb_cmd2 *mode_cmd,
145			       const struct drm_framebuffer_funcs *funcs)
146{
147	const struct drm_format_info *info;
148	struct drm_gem_object *objs[4];
149	int ret, i;
150
151	info = drm_get_format_info(dev, mode_cmd);
152	if (!info) {
153		drm_dbg_kms(dev, "Failed to get FB format info\n");
154		return -EINVAL;
155	}
156
157	for (i = 0; i < info->num_planes; i++) {
158		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
159		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
160		unsigned int min_size;
161
162		objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
163		if (!objs[i]) {
164			drm_dbg_kms(dev, "Failed to lookup GEM object\n");
165			ret = -ENOENT;
166			goto err_gem_object_put;
167		}
168
169		min_size = (height - 1) * mode_cmd->pitches[i]
170			 + drm_format_info_min_pitch(info, i, width)
171			 + mode_cmd->offsets[i];
172
173		if (objs[i]->size < min_size) {
174			drm_dbg_kms(dev,
175				    "GEM object size (%zu) smaller than minimum size (%u) for plane %d\n",
176				    objs[i]->size, min_size, i);
177			drm_gem_object_put(objs[i]);
178			ret = -EINVAL;
179			goto err_gem_object_put;
180		}
181	}
182
183	ret = drm_gem_fb_init(dev, fb, mode_cmd, objs, i, funcs);
184	if (ret)
185		goto err_gem_object_put;
186
187	return 0;
188
189err_gem_object_put:
190	for (i--; i >= 0; i--)
191		drm_gem_object_put(objs[i]);
192
193	return ret;
194}
195EXPORT_SYMBOL_GPL(drm_gem_fb_init_with_funcs);
196
197/**
198 * drm_gem_fb_create_with_funcs() - Helper function for the
199 *                                  &drm_mode_config_funcs.fb_create
200 *                                  callback
201 * @dev: DRM device
202 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
203 * @mode_cmd: Metadata from the userspace framebuffer creation request
204 * @funcs: vtable to be used for the new framebuffer object
205 *
206 * This function can be used to set &drm_framebuffer_funcs for drivers that need
207 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to
208 * change &drm_framebuffer_funcs. The function does buffer size validation.
209 *
210 * Returns:
211 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
212 */
213struct drm_framebuffer *
214drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
215			     const struct drm_mode_fb_cmd2 *mode_cmd,
216			     const struct drm_framebuffer_funcs *funcs)
217{
218	struct drm_framebuffer *fb;
219	int ret;
220
221	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
222	if (!fb)
223		return ERR_PTR(-ENOMEM);
224
225	ret = drm_gem_fb_init_with_funcs(dev, fb, file, mode_cmd, funcs);
226	if (ret) {
227		kfree(fb);
228		return ERR_PTR(ret);
229	}
230
231	return fb;
232}
233EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
234
235static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
236	.destroy	= drm_gem_fb_destroy,
237	.create_handle	= drm_gem_fb_create_handle,
238};
239
240/**
241 * drm_gem_fb_create() - Helper function for the
242 *                       &drm_mode_config_funcs.fb_create callback
243 * @dev: DRM device
244 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
245 * @mode_cmd: Metadata from the userspace framebuffer creation request
246 *
247 * This function creates a new framebuffer object described by
248 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
249 * backing the framebuffer.
250 *
251 * If your hardware has special alignment or pitch requirements these should be
252 * checked before calling this function. The function does buffer size
253 * validation. Use drm_gem_fb_create_with_dirty() if you need framebuffer
254 * flushing.
255 *
256 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
257 * The ADDFB2 IOCTL calls into this callback.
258 *
259 * Returns:
260 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
261 */
262struct drm_framebuffer *
263drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
264		  const struct drm_mode_fb_cmd2 *mode_cmd)
265{
266	return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
267					    &drm_gem_fb_funcs);
268}
269EXPORT_SYMBOL_GPL(drm_gem_fb_create);
270
271static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = {
272	.destroy	= drm_gem_fb_destroy,
273	.create_handle	= drm_gem_fb_create_handle,
274	.dirty		= drm_atomic_helper_dirtyfb,
275};
276
277/**
278 * drm_gem_fb_create_with_dirty() - Helper function for the
279 *                       &drm_mode_config_funcs.fb_create callback
280 * @dev: DRM device
281 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
282 * @mode_cmd: Metadata from the userspace framebuffer creation request
283 *
284 * This function creates a new framebuffer object described by
285 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
286 * backing the framebuffer. drm_atomic_helper_dirtyfb() is used for the dirty
287 * callback giving framebuffer flushing through the atomic machinery. Use
288 * drm_gem_fb_create() if you don't need the dirty callback.
289 * The function does buffer size validation.
290 *
291 * Drivers should also call drm_plane_enable_fb_damage_clips() on all planes
292 * to enable userspace to use damage clips also with the ATOMIC IOCTL.
293 *
294 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
295 * The ADDFB2 IOCTL calls into this callback.
296 *
297 * Returns:
298 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
299 */
300struct drm_framebuffer *
301drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
302			     const struct drm_mode_fb_cmd2 *mode_cmd)
303{
304	return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
305					    &drm_gem_fb_funcs_dirtyfb);
306}
307EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
308
309static __u32 drm_gem_afbc_get_bpp(struct drm_device *dev,
310				  const struct drm_mode_fb_cmd2 *mode_cmd)
311{
312	const struct drm_format_info *info;
313
314	info = drm_get_format_info(dev, mode_cmd);
315
316	/* use whatever a driver has set */
317	if (info->cpp[0])
318		return info->cpp[0] * 8;
319
320	/* guess otherwise */
321	switch (info->format) {
322	case DRM_FORMAT_YUV420_8BIT:
323		return 12;
324	case DRM_FORMAT_YUV420_10BIT:
325		return 15;
326	case DRM_FORMAT_VUY101010:
327		return 30;
328	default:
329		break;
330	}
331
332	/* all attempts failed */
333	return 0;
334}
335
336static int drm_gem_afbc_min_size(struct drm_device *dev,
337				 const struct drm_mode_fb_cmd2 *mode_cmd,
338				 struct drm_afbc_framebuffer *afbc_fb)
339{
340	__u32 n_blocks, w_alignment, h_alignment, hdr_alignment;
341	/* remove bpp when all users properly encode cpp in drm_format_info */
342	__u32 bpp;
343
344	switch (mode_cmd->modifier[0] & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK) {
345	case AFBC_FORMAT_MOD_BLOCK_SIZE_16x16:
346		afbc_fb->block_width = 16;
347		afbc_fb->block_height = 16;
348		break;
349	case AFBC_FORMAT_MOD_BLOCK_SIZE_32x8:
350		afbc_fb->block_width = 32;
351		afbc_fb->block_height = 8;
352		break;
353	/* no user exists yet - fall through */
354	case AFBC_FORMAT_MOD_BLOCK_SIZE_64x4:
355	case AFBC_FORMAT_MOD_BLOCK_SIZE_32x8_64x4:
356	default:
357		drm_dbg_kms(dev, "Invalid AFBC_FORMAT_MOD_BLOCK_SIZE: %lld.\n",
358			    mode_cmd->modifier[0]
359			    & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK);
360		return -EINVAL;
361	}
362
363	/* tiled header afbc */
364	w_alignment = afbc_fb->block_width;
365	h_alignment = afbc_fb->block_height;
366	hdr_alignment = AFBC_HDR_ALIGN;
367	if (mode_cmd->modifier[0] & AFBC_FORMAT_MOD_TILED) {
368		w_alignment *= AFBC_TH_LAYOUT_ALIGNMENT;
369		h_alignment *= AFBC_TH_LAYOUT_ALIGNMENT;
370		hdr_alignment = AFBC_TH_BODY_START_ALIGNMENT;
371	}
372
373	afbc_fb->aligned_width = ALIGN(mode_cmd->width, w_alignment);
374	afbc_fb->aligned_height = ALIGN(mode_cmd->height, h_alignment);
375	afbc_fb->offset = mode_cmd->offsets[0];
376
377	bpp = drm_gem_afbc_get_bpp(dev, mode_cmd);
378	if (!bpp) {
379		drm_dbg_kms(dev, "Invalid AFBC bpp value: %d\n", bpp);
380		return -EINVAL;
381	}
382
383	n_blocks = (afbc_fb->aligned_width * afbc_fb->aligned_height)
384		   / AFBC_SUPERBLOCK_PIXELS;
385	afbc_fb->afbc_size = ALIGN(n_blocks * AFBC_HEADER_SIZE, hdr_alignment);
386	afbc_fb->afbc_size += n_blocks * ALIGN(bpp * AFBC_SUPERBLOCK_PIXELS / 8,
387					       AFBC_SUPERBLOCK_ALIGNMENT);
388
389	return 0;
390}
391
392/**
393 * drm_gem_fb_afbc_init() - Helper function for drivers using afbc to
394 *			    fill and validate all the afbc-specific
395 *			    struct drm_afbc_framebuffer members
396 *
397 * @dev: DRM device
398 * @afbc_fb: afbc-specific framebuffer
399 * @mode_cmd: Metadata from the userspace framebuffer creation request
400 * @afbc_fb: afbc framebuffer
401 *
402 * This function can be used by drivers which support afbc to complete
403 * the preparation of struct drm_afbc_framebuffer. It must be called after
404 * allocating the said struct and calling drm_gem_fb_init_with_funcs().
405 * It is caller's responsibility to put afbc_fb->base.obj objects in case
406 * the call is unsuccessful.
407 *
408 * Returns:
409 * Zero on success or a negative error value on failure.
410 */
411int drm_gem_fb_afbc_init(struct drm_device *dev,
412			 const struct drm_mode_fb_cmd2 *mode_cmd,
413			 struct drm_afbc_framebuffer *afbc_fb)
414{
415	const struct drm_format_info *info;
416	struct drm_gem_object **objs;
417	int ret;
418
419	objs = afbc_fb->base.obj;
420	info = drm_get_format_info(dev, mode_cmd);
421	if (!info)
422		return -EINVAL;
423
424	ret = drm_gem_afbc_min_size(dev, mode_cmd, afbc_fb);
425	if (ret < 0)
426		return ret;
427
428	if (objs[0]->size < afbc_fb->afbc_size)
429		return -EINVAL;
430
431	return 0;
432}
433EXPORT_SYMBOL_GPL(drm_gem_fb_afbc_init);