1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 #include <linux/iosys-map.h>
4 #include <linux/module.h>
5 
6 #include <drm/drm_debugfs.h>
7 #include <drm/drm_device.h>
8 #include <drm/drm_drv.h>
9 #include <drm/drm_file.h>
10 #include <drm/drm_framebuffer.h>
11 #include <drm/drm_gem_atomic_helper.h>
12 #include <drm/drm_gem_framebuffer_helper.h>
13 #include <drm/drm_gem_ttm_helper.h>
14 #include <drm/drm_gem_vram_helper.h>
15 #include <drm/drm_managed.h>
16 #include <drm/drm_mode.h>
17 #include <drm/drm_plane.h>
18 #include <drm/drm_prime.h>
19 #include <drm/drm_simple_kms_helper.h>
20 
21 #include <drm/ttm/ttm_range_manager.h>
22 #include <drm/ttm/ttm_tt.h>
23 
24 static const struct drm_gem_object_funcs drm_gem_vram_object_funcs;
25 
26 /**
27  * DOC: overview
28  *
29  * This library provides &struct drm_gem_vram_object (GEM VRAM), a GEM
30  * buffer object that is backed by video RAM (VRAM). It can be used for
31  * framebuffer devices with dedicated memory.
32  *
33  * The data structure &struct drm_vram_mm and its helpers implement a memory
34  * manager for simple framebuffer devices with dedicated video memory. GEM
35  * VRAM buffer objects are either placed in the video memory or remain evicted
36  * to system memory.
37  *
38  * With the GEM interface userspace applications create, manage and destroy
39  * graphics buffers, such as an on-screen framebuffer. GEM does not provide
40  * an implementation of these interfaces. It's up to the DRM driver to
41  * provide an implementation that suits the hardware. If the hardware device
42  * contains dedicated video memory, the DRM driver can use the VRAM helper
43  * library. Each active buffer object is stored in video RAM. Active
44  * buffer are used for drawing the current frame, typically something like
45  * the frame's scanout buffer or the cursor image. If there's no more space
46  * left in VRAM, inactive GEM objects can be moved to system memory.
47  *
48  * To initialize the VRAM helper library call drmm_vram_helper_alloc_mm().
49  * The function allocates and initializes an instance of &struct drm_vram_mm
50  * in &struct drm_device.vram_mm . Use &DRM_GEM_VRAM_DRIVER to initialize
51  * &struct drm_driver and  &DRM_VRAM_MM_FILE_OPERATIONS to initialize
52  * &struct file_operations; as illustrated below.
53  *
54  * .. code-block:: c
55  *
56  *	struct file_operations fops ={
57  *		.owner = THIS_MODULE,
58  *		DRM_VRAM_MM_FILE_OPERATION
59  *	};
60  *	struct drm_driver drv = {
61  *		.driver_feature = DRM_ ... ,
62  *		.fops = &fops,
63  *		DRM_GEM_VRAM_DRIVER
64  *	};
65  *
66  *	int init_drm_driver()
67  *	{
68  *		struct drm_device *dev;
69  *		uint64_t vram_base;
70  *		unsigned long vram_size;
71  *		int ret;
72  *
73  *		// setup device, vram base and size
74  *		// ...
75  *
76  *		ret = drmm_vram_helper_alloc_mm(dev, vram_base, vram_size);
77  *		if (ret)
78  *			return ret;
79  *		return 0;
80  *	}
81  *
82  * This creates an instance of &struct drm_vram_mm, exports DRM userspace
83  * interfaces for GEM buffer management and initializes file operations to
84  * allow for accessing created GEM buffers. With this setup, the DRM driver
85  * manages an area of video RAM with VRAM MM and provides GEM VRAM objects
86  * to userspace.
87  *
88  * You don't have to clean up the instance of VRAM MM.
89  * drmm_vram_helper_alloc_mm() is a managed interface that installs a
90  * clean-up handler to run during the DRM device's release.
91  *
92  * For drawing or scanout operations, rsp. buffer objects have to be pinned
93  * in video RAM. Call drm_gem_vram_pin() with &DRM_GEM_VRAM_PL_FLAG_VRAM or
94  * &DRM_GEM_VRAM_PL_FLAG_SYSTEM to pin a buffer object in video RAM or system
95  * memory. Call drm_gem_vram_unpin() to release the pinned object afterwards.
96  *
97  * A buffer object that is pinned in video RAM has a fixed address within that
98  * memory region. Call drm_gem_vram_offset() to retrieve this value. Typically
99  * it's used to program the hardware's scanout engine for framebuffers, set
100  * the cursor overlay's image for a mouse cursor, or use it as input to the
101  * hardware's drawing engine.
102  *
103  * To access a buffer object's memory from the DRM driver, call
104  * drm_gem_vram_vmap(). It maps the buffer into kernel address
105  * space and returns the memory address. Use drm_gem_vram_vunmap() to
106  * release the mapping.
107  */
108 
109 /*
110  * Buffer-objects helpers
111  */
112 
113 static void drm_gem_vram_cleanup(struct drm_gem_vram_object *gbo)
114 {
115 	/* We got here via ttm_bo_put(), which means that the
116 	 * TTM buffer object in 'bo' has already been cleaned
117 	 * up; only release the GEM object.
118 	 */
119 
120 	WARN_ON(gbo->vmap_use_count);
121 	WARN_ON(iosys_map_is_set(&gbo->map));
122 
123 	drm_gem_object_release(&gbo->bo.base);
124 }
125 
126 static void drm_gem_vram_destroy(struct drm_gem_vram_object *gbo)
127 {
128 	drm_gem_vram_cleanup(gbo);
129 	kfree(gbo);
130 }
131 
132 static void ttm_buffer_object_destroy(struct ttm_buffer_object *bo)
133 {
134 	struct drm_gem_vram_object *gbo = drm_gem_vram_of_bo(bo);
135 
136 	drm_gem_vram_destroy(gbo);
137 }
138 
139 static void drm_gem_vram_placement(struct drm_gem_vram_object *gbo,
140 				   unsigned long pl_flag)
141 {
142 	u32 invariant_flags = 0;
143 	unsigned int i;
144 	unsigned int c = 0;
145 
146 	if (pl_flag & DRM_GEM_VRAM_PL_FLAG_TOPDOWN)
147 		invariant_flags = TTM_PL_FLAG_TOPDOWN;
148 
149 	gbo->placement.placement = gbo->placements;
150 	gbo->placement.busy_placement = gbo->placements;
151 
152 	if (pl_flag & DRM_GEM_VRAM_PL_FLAG_VRAM) {
153 		gbo->placements[c].mem_type = TTM_PL_VRAM;
154 		gbo->placements[c++].flags = invariant_flags;
155 	}
156 
157 	if (pl_flag & DRM_GEM_VRAM_PL_FLAG_SYSTEM || !c) {
158 		gbo->placements[c].mem_type = TTM_PL_SYSTEM;
159 		gbo->placements[c++].flags = invariant_flags;
160 	}
161 
162 	gbo->placement.num_placement = c;
163 	gbo->placement.num_busy_placement = c;
164 
165 	for (i = 0; i < c; ++i) {
166 		gbo->placements[i].fpfn = 0;
167 		gbo->placements[i].lpfn = 0;
168 	}
169 }
170 
171 /**
172  * drm_gem_vram_create() - Creates a VRAM-backed GEM object
173  * @dev:		the DRM device
174  * @size:		the buffer size in bytes
175  * @pg_align:		the buffer's alignment in multiples of the page size
176  *
177  * GEM objects are allocated by calling struct drm_driver.gem_create_object,
178  * if set. Otherwise kzalloc() will be used. Drivers can set their own GEM
179  * object functions in struct drm_driver.gem_create_object. If no functions
180  * are set, the new GEM object will use the default functions from GEM VRAM
181  * helpers.
182  *
183  * Returns:
184  * A new instance of &struct drm_gem_vram_object on success, or
185  * an ERR_PTR()-encoded error code otherwise.
186  */
187 struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
188 						size_t size,
189 						unsigned long pg_align)
190 {
191 	struct drm_gem_vram_object *gbo;
192 	struct drm_gem_object *gem;
193 	struct drm_vram_mm *vmm = dev->vram_mm;
194 	struct ttm_device *bdev;
195 	int ret;
196 
197 	if (WARN_ONCE(!vmm, "VRAM MM not initialized"))
198 		return ERR_PTR(-EINVAL);
199 
200 	if (dev->driver->gem_create_object) {
201 		gem = dev->driver->gem_create_object(dev, size);
202 		if (IS_ERR(gem))
203 			return ERR_CAST(gem);
204 		gbo = drm_gem_vram_of_gem(gem);
205 	} else {
206 		gbo = kzalloc(sizeof(*gbo), GFP_KERNEL);
207 		if (!gbo)
208 			return ERR_PTR(-ENOMEM);
209 		gem = &gbo->bo.base;
210 	}
211 
212 	if (!gem->funcs)
213 		gem->funcs = &drm_gem_vram_object_funcs;
214 
215 	ret = drm_gem_object_init(dev, gem, size);
216 	if (ret) {
217 		kfree(gbo);
218 		return ERR_PTR(ret);
219 	}
220 
221 	bdev = &vmm->bdev;
222 
223 	gbo->bo.bdev = bdev;
224 	drm_gem_vram_placement(gbo, DRM_GEM_VRAM_PL_FLAG_SYSTEM);
225 
226 	/*
227 	 * A failing ttm_bo_init will call ttm_buffer_object_destroy
228 	 * to release gbo->bo.base and kfree gbo.
229 	 */
230 	ret = ttm_bo_init_validate(bdev, &gbo->bo, ttm_bo_type_device,
231 				   &gbo->placement, pg_align, false, NULL, NULL,
232 				   ttm_buffer_object_destroy);
233 	if (ret)
234 		return ERR_PTR(ret);
235 
236 	return gbo;
237 }
238 EXPORT_SYMBOL(drm_gem_vram_create);
239 
240 /**
241  * drm_gem_vram_put() - Releases a reference to a VRAM-backed GEM object
242  * @gbo:	the GEM VRAM object
243  *
244  * See ttm_bo_put() for more information.
245  */
246 void drm_gem_vram_put(struct drm_gem_vram_object *gbo)
247 {
248 	ttm_bo_put(&gbo->bo);
249 }
250 EXPORT_SYMBOL(drm_gem_vram_put);
251 
252 static u64 drm_gem_vram_pg_offset(struct drm_gem_vram_object *gbo)
253 {
254 	/* Keep TTM behavior for now, remove when drivers are audited */
255 	if (WARN_ON_ONCE(!gbo->bo.resource ||
256 			 gbo->bo.resource->mem_type == TTM_PL_SYSTEM))
257 		return 0;
258 
259 	return gbo->bo.resource->start;
260 }
261 
262 /**
263  * drm_gem_vram_offset() - \
264 	Returns a GEM VRAM object's offset in video memory
265  * @gbo:	the GEM VRAM object
266  *
267  * This function returns the buffer object's offset in the device's video
268  * memory. The buffer object has to be pinned to %TTM_PL_VRAM.
269  *
270  * Returns:
271  * The buffer object's offset in video memory on success, or
272  * a negative errno code otherwise.
273  */
274 s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo)
275 {
276 	if (WARN_ON_ONCE(!gbo->bo.pin_count))
277 		return (s64)-ENODEV;
278 	return drm_gem_vram_pg_offset(gbo) << PAGE_SHIFT;
279 }
280 EXPORT_SYMBOL(drm_gem_vram_offset);
281 
282 static int drm_gem_vram_pin_locked(struct drm_gem_vram_object *gbo,
283 				   unsigned long pl_flag)
284 {
285 	struct ttm_operation_ctx ctx = { false, false };
286 	int ret;
287 
288 	if (gbo->bo.pin_count)
289 		goto out;
290 
291 	if (pl_flag)
292 		drm_gem_vram_placement(gbo, pl_flag);
293 
294 	ret = ttm_bo_validate(&gbo->bo, &gbo->placement, &ctx);
295 	if (ret < 0)
296 		return ret;
297 
298 out:
299 	ttm_bo_pin(&gbo->bo);
300 
301 	return 0;
302 }
303 
304 /**
305  * drm_gem_vram_pin() - Pins a GEM VRAM object in a region.
306  * @gbo:	the GEM VRAM object
307  * @pl_flag:	a bitmask of possible memory regions
308  *
309  * Pinning a buffer object ensures that it is not evicted from
310  * a memory region. A pinned buffer object has to be unpinned before
311  * it can be pinned to another region. If the pl_flag argument is 0,
312  * the buffer is pinned at its current location (video RAM or system
313  * memory).
314  *
315  * Small buffer objects, such as cursor images, can lead to memory
316  * fragmentation if they are pinned in the middle of video RAM. This
317  * is especially a problem on devices with only a small amount of
318  * video RAM. Fragmentation can prevent the primary framebuffer from
319  * fitting in, even though there's enough memory overall. The modifier
320  * DRM_GEM_VRAM_PL_FLAG_TOPDOWN marks the buffer object to be pinned
321  * at the high end of the memory region to avoid fragmentation.
322  *
323  * Returns:
324  * 0 on success, or
325  * a negative error code otherwise.
326  */
327 int drm_gem_vram_pin(struct drm_gem_vram_object *gbo, unsigned long pl_flag)
328 {
329 	int ret;
330 
331 	ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
332 	if (ret)
333 		return ret;
334 	ret = drm_gem_vram_pin_locked(gbo, pl_flag);
335 	ttm_bo_unreserve(&gbo->bo);
336 
337 	return ret;
338 }
339 EXPORT_SYMBOL(drm_gem_vram_pin);
340 
341 static void drm_gem_vram_unpin_locked(struct drm_gem_vram_object *gbo)
342 {
343 	ttm_bo_unpin(&gbo->bo);
344 }
345 
346 /**
347  * drm_gem_vram_unpin() - Unpins a GEM VRAM object
348  * @gbo:	the GEM VRAM object
349  *
350  * Returns:
351  * 0 on success, or
352  * a negative error code otherwise.
353  */
354 int drm_gem_vram_unpin(struct drm_gem_vram_object *gbo)
355 {
356 	int ret;
357 
358 	ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
359 	if (ret)
360 		return ret;
361 
362 	drm_gem_vram_unpin_locked(gbo);
363 	ttm_bo_unreserve(&gbo->bo);
364 
365 	return 0;
366 }
367 EXPORT_SYMBOL(drm_gem_vram_unpin);
368 
369 static int drm_gem_vram_kmap_locked(struct drm_gem_vram_object *gbo,
370 				    struct iosys_map *map)
371 {
372 	int ret;
373 
374 	if (gbo->vmap_use_count > 0)
375 		goto out;
376 
377 	/*
378 	 * VRAM helpers unmap the BO only on demand. So the previous
379 	 * page mapping might still be around. Only vmap if the there's
380 	 * no mapping present.
381 	 */
382 	if (iosys_map_is_null(&gbo->map)) {
383 		ret = ttm_bo_vmap(&gbo->bo, &gbo->map);
384 		if (ret)
385 			return ret;
386 	}
387 
388 out:
389 	++gbo->vmap_use_count;
390 	*map = gbo->map;
391 
392 	return 0;
393 }
394 
395 static void drm_gem_vram_kunmap_locked(struct drm_gem_vram_object *gbo,
396 				       struct iosys_map *map)
397 {
398 	struct drm_device *dev = gbo->bo.base.dev;
399 
400 	if (drm_WARN_ON_ONCE(dev, !gbo->vmap_use_count))
401 		return;
402 
403 	if (drm_WARN_ON_ONCE(dev, !iosys_map_is_equal(&gbo->map, map)))
404 		return; /* BUG: map not mapped from this BO */
405 
406 	if (--gbo->vmap_use_count > 0)
407 		return;
408 
409 	/*
410 	 * Permanently mapping and unmapping buffers adds overhead from
411 	 * updating the page tables and creates debugging output. Therefore,
412 	 * we delay the actual unmap operation until the BO gets evicted
413 	 * from memory. See drm_gem_vram_bo_driver_move_notify().
414 	 */
415 }
416 
417 /**
418  * drm_gem_vram_vmap() - Pins and maps a GEM VRAM object into kernel address
419  *                       space
420  * @gbo: The GEM VRAM object to map
421  * @map: Returns the kernel virtual address of the VRAM GEM object's backing
422  *       store.
423  *
424  * The vmap function pins a GEM VRAM object to its current location, either
425  * system or video memory, and maps its buffer into kernel address space.
426  * As pinned object cannot be relocated, you should avoid pinning objects
427  * permanently. Call drm_gem_vram_vunmap() with the returned address to
428  * unmap and unpin the GEM VRAM object.
429  *
430  * Returns:
431  * 0 on success, or a negative error code otherwise.
432  */
433 int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct iosys_map *map)
434 {
435 	int ret;
436 
437 	dma_resv_assert_held(gbo->bo.base.resv);
438 
439 	ret = drm_gem_vram_pin_locked(gbo, 0);
440 	if (ret)
441 		return ret;
442 	ret = drm_gem_vram_kmap_locked(gbo, map);
443 	if (ret)
444 		goto err_drm_gem_vram_unpin_locked;
445 
446 	return 0;
447 
448 err_drm_gem_vram_unpin_locked:
449 	drm_gem_vram_unpin_locked(gbo);
450 	return ret;
451 }
452 EXPORT_SYMBOL(drm_gem_vram_vmap);
453 
454 /**
455  * drm_gem_vram_vunmap() - Unmaps and unpins a GEM VRAM object
456  * @gbo: The GEM VRAM object to unmap
457  * @map: Kernel virtual address where the VRAM GEM object was mapped
458  *
459  * A call to drm_gem_vram_vunmap() unmaps and unpins a GEM VRAM buffer. See
460  * the documentation for drm_gem_vram_vmap() for more information.
461  */
462 void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo,
463 			 struct iosys_map *map)
464 {
465 	dma_resv_assert_held(gbo->bo.base.resv);
466 
467 	drm_gem_vram_kunmap_locked(gbo, map);
468 	drm_gem_vram_unpin_locked(gbo);
469 }
470 EXPORT_SYMBOL(drm_gem_vram_vunmap);
471 
472 /**
473  * drm_gem_vram_fill_create_dumb() - \
474 	Helper for implementing &struct drm_driver.dumb_create
475  * @file:		the DRM file
476  * @dev:		the DRM device
477  * @pg_align:		the buffer's alignment in multiples of the page size
478  * @pitch_align:	the scanline's alignment in powers of 2
479  * @args:		the arguments as provided to \
480 				&struct drm_driver.dumb_create
481  *
482  * This helper function fills &struct drm_mode_create_dumb, which is used
483  * by &struct drm_driver.dumb_create. Implementations of this interface
484  * should forwards their arguments to this helper, plus the driver-specific
485  * parameters.
486  *
487  * Returns:
488  * 0 on success, or
489  * a negative error code otherwise.
490  */
491 int drm_gem_vram_fill_create_dumb(struct drm_file *file,
492 				  struct drm_device *dev,
493 				  unsigned long pg_align,
494 				  unsigned long pitch_align,
495 				  struct drm_mode_create_dumb *args)
496 {
497 	size_t pitch, size;
498 	struct drm_gem_vram_object *gbo;
499 	int ret;
500 	u32 handle;
501 
502 	pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
503 	if (pitch_align) {
504 		if (WARN_ON_ONCE(!is_power_of_2(pitch_align)))
505 			return -EINVAL;
506 		pitch = ALIGN(pitch, pitch_align);
507 	}
508 	size = pitch * args->height;
509 
510 	size = roundup(size, PAGE_SIZE);
511 	if (!size)
512 		return -EINVAL;
513 
514 	gbo = drm_gem_vram_create(dev, size, pg_align);
515 	if (IS_ERR(gbo))
516 		return PTR_ERR(gbo);
517 
518 	ret = drm_gem_handle_create(file, &gbo->bo.base, &handle);
519 	if (ret)
520 		goto err_drm_gem_object_put;
521 
522 	drm_gem_object_put(&gbo->bo.base);
523 
524 	args->pitch = pitch;
525 	args->size = size;
526 	args->handle = handle;
527 
528 	return 0;
529 
530 err_drm_gem_object_put:
531 	drm_gem_object_put(&gbo->bo.base);
532 	return ret;
533 }
534 EXPORT_SYMBOL(drm_gem_vram_fill_create_dumb);
535 
536 /*
537  * Helpers for struct ttm_device_funcs
538  */
539 
540 static bool drm_is_gem_vram(struct ttm_buffer_object *bo)
541 {
542 	return (bo->destroy == ttm_buffer_object_destroy);
543 }
544 
545 static void drm_gem_vram_bo_driver_evict_flags(struct drm_gem_vram_object *gbo,
546 					       struct ttm_placement *pl)
547 {
548 	drm_gem_vram_placement(gbo, DRM_GEM_VRAM_PL_FLAG_SYSTEM);
549 	*pl = gbo->placement;
550 }
551 
552 static void drm_gem_vram_bo_driver_move_notify(struct drm_gem_vram_object *gbo)
553 {
554 	struct ttm_buffer_object *bo = &gbo->bo;
555 	struct drm_device *dev = bo->base.dev;
556 
557 	if (drm_WARN_ON_ONCE(dev, gbo->vmap_use_count))
558 		return;
559 
560 	ttm_bo_vunmap(bo, &gbo->map);
561 	iosys_map_clear(&gbo->map); /* explicitly clear mapping for next vmap call */
562 }
563 
564 static int drm_gem_vram_bo_driver_move(struct drm_gem_vram_object *gbo,
565 				       bool evict,
566 				       struct ttm_operation_ctx *ctx,
567 				       struct ttm_resource *new_mem)
568 {
569 	drm_gem_vram_bo_driver_move_notify(gbo);
570 	return ttm_bo_move_memcpy(&gbo->bo, ctx, new_mem);
571 }
572 
573 /*
574  * Helpers for struct drm_gem_object_funcs
575  */
576 
577 /**
578  * drm_gem_vram_object_free() - \
579 	Implements &struct drm_gem_object_funcs.free
580  * @gem:       GEM object. Refers to &struct drm_gem_vram_object.gem
581  */
582 static void drm_gem_vram_object_free(struct drm_gem_object *gem)
583 {
584 	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
585 
586 	drm_gem_vram_put(gbo);
587 }
588 
589 /*
590  * Helpers for dump buffers
591  */
592 
593 /**
594  * drm_gem_vram_driver_dumb_create() - \
595 	Implements &struct drm_driver.dumb_create
596  * @file:		the DRM file
597  * @dev:		the DRM device
598  * @args:		the arguments as provided to \
599 				&struct drm_driver.dumb_create
600  *
601  * This function requires the driver to use @drm_device.vram_mm for its
602  * instance of VRAM MM.
603  *
604  * Returns:
605  * 0 on success, or
606  * a negative error code otherwise.
607  */
608 int drm_gem_vram_driver_dumb_create(struct drm_file *file,
609 				    struct drm_device *dev,
610 				    struct drm_mode_create_dumb *args)
611 {
612 	if (WARN_ONCE(!dev->vram_mm, "VRAM MM not initialized"))
613 		return -EINVAL;
614 
615 	return drm_gem_vram_fill_create_dumb(file, dev, 0, 0, args);
616 }
617 EXPORT_SYMBOL(drm_gem_vram_driver_dumb_create);
618 
619 /*
620  * Helpers for struct drm_plane_helper_funcs
621  */
622 
623 static void __drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
624 						   struct drm_plane_state *state,
625 						   unsigned int num_planes)
626 {
627 	struct drm_gem_object *obj;
628 	struct drm_gem_vram_object *gbo;
629 	struct drm_framebuffer *fb = state->fb;
630 
631 	while (num_planes) {
632 		--num_planes;
633 		obj = drm_gem_fb_get_obj(fb, num_planes);
634 		if (!obj)
635 			continue;
636 		gbo = drm_gem_vram_of_gem(obj);
637 		drm_gem_vram_unpin(gbo);
638 	}
639 }
640 
641 /**
642  * drm_gem_vram_plane_helper_prepare_fb() - \
643  *	Implements &struct drm_plane_helper_funcs.prepare_fb
644  * @plane:	a DRM plane
645  * @new_state:	the plane's new state
646  *
647  * During plane updates, this function sets the plane's fence and
648  * pins the GEM VRAM objects of the plane's new framebuffer to VRAM.
649  * Call drm_gem_vram_plane_helper_cleanup_fb() to unpin them.
650  *
651  * Returns:
652  *	0 on success, or
653  *	a negative errno code otherwise.
654  */
655 int
656 drm_gem_vram_plane_helper_prepare_fb(struct drm_plane *plane,
657 				     struct drm_plane_state *new_state)
658 {
659 	struct drm_framebuffer *fb = new_state->fb;
660 	struct drm_gem_vram_object *gbo;
661 	struct drm_gem_object *obj;
662 	unsigned int i;
663 	int ret;
664 
665 	if (!fb)
666 		return 0;
667 
668 	for (i = 0; i < fb->format->num_planes; ++i) {
669 		obj = drm_gem_fb_get_obj(fb, i);
670 		if (!obj) {
671 			ret = -EINVAL;
672 			goto err_drm_gem_vram_unpin;
673 		}
674 		gbo = drm_gem_vram_of_gem(obj);
675 		ret = drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM);
676 		if (ret)
677 			goto err_drm_gem_vram_unpin;
678 	}
679 
680 	ret = drm_gem_plane_helper_prepare_fb(plane, new_state);
681 	if (ret)
682 		goto err_drm_gem_vram_unpin;
683 
684 	return 0;
685 
686 err_drm_gem_vram_unpin:
687 	__drm_gem_vram_plane_helper_cleanup_fb(plane, new_state, i);
688 	return ret;
689 }
690 EXPORT_SYMBOL(drm_gem_vram_plane_helper_prepare_fb);
691 
692 /**
693  * drm_gem_vram_plane_helper_cleanup_fb() - \
694  *	Implements &struct drm_plane_helper_funcs.cleanup_fb
695  * @plane:	a DRM plane
696  * @old_state:	the plane's old state
697  *
698  * During plane updates, this function unpins the GEM VRAM
699  * objects of the plane's old framebuffer from VRAM. Complements
700  * drm_gem_vram_plane_helper_prepare_fb().
701  */
702 void
703 drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
704 				     struct drm_plane_state *old_state)
705 {
706 	struct drm_framebuffer *fb = old_state->fb;
707 
708 	if (!fb)
709 		return;
710 
711 	__drm_gem_vram_plane_helper_cleanup_fb(plane, old_state, fb->format->num_planes);
712 }
713 EXPORT_SYMBOL(drm_gem_vram_plane_helper_cleanup_fb);
714 
715 /*
716  * Helpers for struct drm_simple_display_pipe_funcs
717  */
718 
719 /**
720  * drm_gem_vram_simple_display_pipe_prepare_fb() - \
721  *	Implements &struct drm_simple_display_pipe_funcs.prepare_fb
722  * @pipe:	a simple display pipe
723  * @new_state:	the plane's new state
724  *
725  * During plane updates, this function pins the GEM VRAM
726  * objects of the plane's new framebuffer to VRAM. Call
727  * drm_gem_vram_simple_display_pipe_cleanup_fb() to unpin them.
728  *
729  * Returns:
730  *	0 on success, or
731  *	a negative errno code otherwise.
732  */
733 int drm_gem_vram_simple_display_pipe_prepare_fb(
734 	struct drm_simple_display_pipe *pipe,
735 	struct drm_plane_state *new_state)
736 {
737 	return drm_gem_vram_plane_helper_prepare_fb(&pipe->plane, new_state);
738 }
739 EXPORT_SYMBOL(drm_gem_vram_simple_display_pipe_prepare_fb);
740 
741 /**
742  * drm_gem_vram_simple_display_pipe_cleanup_fb() - \
743  *	Implements &struct drm_simple_display_pipe_funcs.cleanup_fb
744  * @pipe:	a simple display pipe
745  * @old_state:	the plane's old state
746  *
747  * During plane updates, this function unpins the GEM VRAM
748  * objects of the plane's old framebuffer from VRAM. Complements
749  * drm_gem_vram_simple_display_pipe_prepare_fb().
750  */
751 void drm_gem_vram_simple_display_pipe_cleanup_fb(
752 	struct drm_simple_display_pipe *pipe,
753 	struct drm_plane_state *old_state)
754 {
755 	drm_gem_vram_plane_helper_cleanup_fb(&pipe->plane, old_state);
756 }
757 EXPORT_SYMBOL(drm_gem_vram_simple_display_pipe_cleanup_fb);
758 
759 /*
760  * PRIME helpers
761  */
762 
763 /**
764  * drm_gem_vram_object_pin() - \
765 	Implements &struct drm_gem_object_funcs.pin
766  * @gem:	The GEM object to pin
767  *
768  * Returns:
769  * 0 on success, or
770  * a negative errno code otherwise.
771  */
772 static int drm_gem_vram_object_pin(struct drm_gem_object *gem)
773 {
774 	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
775 
776 	/* Fbdev console emulation is the use case of these PRIME
777 	 * helpers. This may involve updating a hardware buffer from
778 	 * a shadow FB. We pin the buffer to it's current location
779 	 * (either video RAM or system memory) to prevent it from
780 	 * being relocated during the update operation. If you require
781 	 * the buffer to be pinned to VRAM, implement a callback that
782 	 * sets the flags accordingly.
783 	 */
784 	return drm_gem_vram_pin(gbo, 0);
785 }
786 
787 /**
788  * drm_gem_vram_object_unpin() - \
789 	Implements &struct drm_gem_object_funcs.unpin
790  * @gem:	The GEM object to unpin
791  */
792 static void drm_gem_vram_object_unpin(struct drm_gem_object *gem)
793 {
794 	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
795 
796 	drm_gem_vram_unpin(gbo);
797 }
798 
799 /**
800  * drm_gem_vram_object_vmap() -
801  *	Implements &struct drm_gem_object_funcs.vmap
802  * @gem: The GEM object to map
803  * @map: Returns the kernel virtual address of the VRAM GEM object's backing
804  *       store.
805  *
806  * Returns:
807  * 0 on success, or a negative error code otherwise.
808  */
809 static int drm_gem_vram_object_vmap(struct drm_gem_object *gem,
810 				    struct iosys_map *map)
811 {
812 	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
813 
814 	return drm_gem_vram_vmap(gbo, map);
815 }
816 
817 /**
818  * drm_gem_vram_object_vunmap() -
819  *	Implements &struct drm_gem_object_funcs.vunmap
820  * @gem: The GEM object to unmap
821  * @map: Kernel virtual address where the VRAM GEM object was mapped
822  */
823 static void drm_gem_vram_object_vunmap(struct drm_gem_object *gem,
824 				       struct iosys_map *map)
825 {
826 	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
827 
828 	drm_gem_vram_vunmap(gbo, map);
829 }
830 
831 /*
832  * GEM object funcs
833  */
834 
835 static const struct drm_gem_object_funcs drm_gem_vram_object_funcs = {
836 	.free	= drm_gem_vram_object_free,
837 	.pin	= drm_gem_vram_object_pin,
838 	.unpin	= drm_gem_vram_object_unpin,
839 	.vmap	= drm_gem_vram_object_vmap,
840 	.vunmap	= drm_gem_vram_object_vunmap,
841 	.mmap   = drm_gem_ttm_mmap,
842 	.print_info = drm_gem_ttm_print_info,
843 };
844 
845 /*
846  * VRAM memory manager
847  */
848 
849 /*
850  * TTM TT
851  */
852 
853 static void bo_driver_ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *tt)
854 {
855 	ttm_tt_fini(tt);
856 	kfree(tt);
857 }
858 
859 /*
860  * TTM BO device
861  */
862 
863 static struct ttm_tt *bo_driver_ttm_tt_create(struct ttm_buffer_object *bo,
864 					      uint32_t page_flags)
865 {
866 	struct ttm_tt *tt;
867 	int ret;
868 
869 	tt = kzalloc(sizeof(*tt), GFP_KERNEL);
870 	if (!tt)
871 		return NULL;
872 
873 	ret = ttm_tt_init(tt, bo, page_flags, ttm_cached, 0);
874 	if (ret < 0)
875 		goto err_ttm_tt_init;
876 
877 	return tt;
878 
879 err_ttm_tt_init:
880 	kfree(tt);
881 	return NULL;
882 }
883 
884 static void bo_driver_evict_flags(struct ttm_buffer_object *bo,
885 				  struct ttm_placement *placement)
886 {
887 	struct drm_gem_vram_object *gbo;
888 
889 	/* TTM may pass BOs that are not GEM VRAM BOs. */
890 	if (!drm_is_gem_vram(bo))
891 		return;
892 
893 	gbo = drm_gem_vram_of_bo(bo);
894 
895 	drm_gem_vram_bo_driver_evict_flags(gbo, placement);
896 }
897 
898 static void bo_driver_delete_mem_notify(struct ttm_buffer_object *bo)
899 {
900 	struct drm_gem_vram_object *gbo;
901 
902 	/* TTM may pass BOs that are not GEM VRAM BOs. */
903 	if (!drm_is_gem_vram(bo))
904 		return;
905 
906 	gbo = drm_gem_vram_of_bo(bo);
907 
908 	drm_gem_vram_bo_driver_move_notify(gbo);
909 }
910 
911 static int bo_driver_move(struct ttm_buffer_object *bo,
912 			  bool evict,
913 			  struct ttm_operation_ctx *ctx,
914 			  struct ttm_resource *new_mem,
915 			  struct ttm_place *hop)
916 {
917 	struct drm_gem_vram_object *gbo;
918 
919 	if (!bo->resource) {
920 		if (new_mem->mem_type != TTM_PL_SYSTEM) {
921 			hop->mem_type = TTM_PL_SYSTEM;
922 			hop->flags = TTM_PL_FLAG_TEMPORARY;
923 			return -EMULTIHOP;
924 		}
925 
926 		ttm_bo_move_null(bo, new_mem);
927 		return 0;
928 	}
929 
930 	gbo = drm_gem_vram_of_bo(bo);
931 
932 	return drm_gem_vram_bo_driver_move(gbo, evict, ctx, new_mem);
933 }
934 
935 static int bo_driver_io_mem_reserve(struct ttm_device *bdev,
936 				    struct ttm_resource *mem)
937 {
938 	struct drm_vram_mm *vmm = drm_vram_mm_of_bdev(bdev);
939 
940 	switch (mem->mem_type) {
941 	case TTM_PL_SYSTEM:	/* nothing to do */
942 		break;
943 	case TTM_PL_VRAM:
944 		mem->bus.offset = (mem->start << PAGE_SHIFT) + vmm->vram_base;
945 		mem->bus.is_iomem = true;
946 		mem->bus.caching = ttm_write_combined;
947 		break;
948 	default:
949 		return -EINVAL;
950 	}
951 
952 	return 0;
953 }
954 
955 static struct ttm_device_funcs bo_driver = {
956 	.ttm_tt_create = bo_driver_ttm_tt_create,
957 	.ttm_tt_destroy = bo_driver_ttm_tt_destroy,
958 	.eviction_valuable = ttm_bo_eviction_valuable,
959 	.evict_flags = bo_driver_evict_flags,
960 	.move = bo_driver_move,
961 	.delete_mem_notify = bo_driver_delete_mem_notify,
962 	.io_mem_reserve = bo_driver_io_mem_reserve,
963 };
964 
965 /*
966  * struct drm_vram_mm
967  */
968 
969 static int drm_vram_mm_debugfs(struct seq_file *m, void *data)
970 {
971 	struct drm_debugfs_entry *entry = m->private;
972 	struct drm_vram_mm *vmm = entry->dev->vram_mm;
973 	struct ttm_resource_manager *man = ttm_manager_type(&vmm->bdev, TTM_PL_VRAM);
974 	struct drm_printer p = drm_seq_file_printer(m);
975 
976 	ttm_resource_manager_debug(man, &p);
977 	return 0;
978 }
979 
980 static const struct drm_debugfs_info drm_vram_mm_debugfs_list[] = {
981 	{ "vram-mm", drm_vram_mm_debugfs, 0, NULL },
982 };
983 
984 /**
985  * drm_vram_mm_debugfs_init() - Register VRAM MM debugfs file.
986  *
987  * @minor: drm minor device.
988  *
989  */
990 void drm_vram_mm_debugfs_init(struct drm_minor *minor)
991 {
992 	drm_debugfs_add_files(minor->dev, drm_vram_mm_debugfs_list,
993 			      ARRAY_SIZE(drm_vram_mm_debugfs_list));
994 }
995 EXPORT_SYMBOL(drm_vram_mm_debugfs_init);
996 
997 static int drm_vram_mm_init(struct drm_vram_mm *vmm, struct drm_device *dev,
998 			    uint64_t vram_base, size_t vram_size)
999 {
1000 	int ret;
1001 
1002 	vmm->vram_base = vram_base;
1003 	vmm->vram_size = vram_size;
1004 
1005 	ret = ttm_device_init(&vmm->bdev, &bo_driver, dev->dev,
1006 				 dev->anon_inode->i_mapping,
1007 				 dev->vma_offset_manager,
1008 				 false, true);
1009 	if (ret)
1010 		return ret;
1011 
1012 	ret = ttm_range_man_init(&vmm->bdev, TTM_PL_VRAM,
1013 				 false, vram_size >> PAGE_SHIFT);
1014 	if (ret)
1015 		return ret;
1016 
1017 	return 0;
1018 }
1019 
1020 static void drm_vram_mm_cleanup(struct drm_vram_mm *vmm)
1021 {
1022 	ttm_range_man_fini(&vmm->bdev, TTM_PL_VRAM);
1023 	ttm_device_fini(&vmm->bdev);
1024 }
1025 
1026 /*
1027  * Helpers for integration with struct drm_device
1028  */
1029 
1030 static struct drm_vram_mm *drm_vram_helper_alloc_mm(struct drm_device *dev, uint64_t vram_base,
1031 						    size_t vram_size)
1032 {
1033 	int ret;
1034 
1035 	if (WARN_ON(dev->vram_mm))
1036 		return dev->vram_mm;
1037 
1038 	dev->vram_mm = kzalloc(sizeof(*dev->vram_mm), GFP_KERNEL);
1039 	if (!dev->vram_mm)
1040 		return ERR_PTR(-ENOMEM);
1041 
1042 	ret = drm_vram_mm_init(dev->vram_mm, dev, vram_base, vram_size);
1043 	if (ret)
1044 		goto err_kfree;
1045 
1046 	return dev->vram_mm;
1047 
1048 err_kfree:
1049 	kfree(dev->vram_mm);
1050 	dev->vram_mm = NULL;
1051 	return ERR_PTR(ret);
1052 }
1053 
1054 static void drm_vram_helper_release_mm(struct drm_device *dev)
1055 {
1056 	if (!dev->vram_mm)
1057 		return;
1058 
1059 	drm_vram_mm_cleanup(dev->vram_mm);
1060 	kfree(dev->vram_mm);
1061 	dev->vram_mm = NULL;
1062 }
1063 
1064 static void drm_vram_mm_release(struct drm_device *dev, void *ptr)
1065 {
1066 	drm_vram_helper_release_mm(dev);
1067 }
1068 
1069 /**
1070  * drmm_vram_helper_init - Initializes a device's instance of
1071  *                         &struct drm_vram_mm
1072  * @dev:	the DRM device
1073  * @vram_base:	the base address of the video memory
1074  * @vram_size:	the size of the video memory in bytes
1075  *
1076  * Creates a new instance of &struct drm_vram_mm and stores it in
1077  * struct &drm_device.vram_mm. The instance is auto-managed and cleaned
1078  * up as part of device cleanup. Calling this function multiple times
1079  * will generate an error message.
1080  *
1081  * Returns:
1082  * 0 on success, or a negative errno code otherwise.
1083  */
1084 int drmm_vram_helper_init(struct drm_device *dev, uint64_t vram_base,
1085 			  size_t vram_size)
1086 {
1087 	struct drm_vram_mm *vram_mm;
1088 
1089 	if (drm_WARN_ON_ONCE(dev, dev->vram_mm))
1090 		return 0;
1091 
1092 	vram_mm = drm_vram_helper_alloc_mm(dev, vram_base, vram_size);
1093 	if (IS_ERR(vram_mm))
1094 		return PTR_ERR(vram_mm);
1095 	return drmm_add_action_or_reset(dev, drm_vram_mm_release, NULL);
1096 }
1097 EXPORT_SYMBOL(drmm_vram_helper_init);
1098 
1099 /*
1100  * Mode-config helpers
1101  */
1102 
1103 static enum drm_mode_status
1104 drm_vram_helper_mode_valid_internal(struct drm_device *dev,
1105 				    const struct drm_display_mode *mode,
1106 				    unsigned long max_bpp)
1107 {
1108 	struct drm_vram_mm *vmm = dev->vram_mm;
1109 	unsigned long fbsize, fbpages, max_fbpages;
1110 
1111 	if (WARN_ON(!dev->vram_mm))
1112 		return MODE_BAD;
1113 
1114 	max_fbpages = (vmm->vram_size / 2) >> PAGE_SHIFT;
1115 
1116 	fbsize = mode->hdisplay * mode->vdisplay * max_bpp;
1117 	fbpages = DIV_ROUND_UP(fbsize, PAGE_SIZE);
1118 
1119 	if (fbpages > max_fbpages)
1120 		return MODE_MEM;
1121 
1122 	return MODE_OK;
1123 }
1124 
1125 /**
1126  * drm_vram_helper_mode_valid - Tests if a display mode's
1127  *	framebuffer fits into the available video memory.
1128  * @dev:	the DRM device
1129  * @mode:	the mode to test
1130  *
1131  * This function tests if enough video memory is available for using the
1132  * specified display mode. Atomic modesetting requires importing the
1133  * designated framebuffer into video memory before evicting the active
1134  * one. Hence, any framebuffer may consume at most half of the available
1135  * VRAM. Display modes that require a larger framebuffer can not be used,
1136  * even if the CRTC does support them. Each framebuffer is assumed to
1137  * have 32-bit color depth.
1138  *
1139  * Note:
1140  * The function can only test if the display mode is supported in
1141  * general. If there are too many framebuffers pinned to video memory,
1142  * a display mode may still not be usable in practice. The color depth of
1143  * 32-bit fits all current use case. A more flexible test can be added
1144  * when necessary.
1145  *
1146  * Returns:
1147  * MODE_OK if the display mode is supported, or an error code of type
1148  * enum drm_mode_status otherwise.
1149  */
1150 enum drm_mode_status
1151 drm_vram_helper_mode_valid(struct drm_device *dev,
1152 			   const struct drm_display_mode *mode)
1153 {
1154 	static const unsigned long max_bpp = 4; /* DRM_FORMAT_XRGB8888 */
1155 
1156 	return drm_vram_helper_mode_valid_internal(dev, mode, max_bpp);
1157 }
1158 EXPORT_SYMBOL(drm_vram_helper_mode_valid);
1159 
1160 MODULE_DESCRIPTION("DRM VRAM memory-management helpers");
1161 MODULE_LICENSE("GPL");
1162