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v3.1
 
  1/**************************************************************************
  2 *
  3 * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
  4 * All Rights Reserved.
  5 *
  6 * Permission is hereby granted, free of charge, to any person obtaining a
  7 * copy of this software and associated documentation files (the
  8 * "Software"), to deal in the Software without restriction, including
  9 * without limitation the rights to use, copy, modify, merge, publish,
 10 * distribute, sub license, and/or sell copies of the Software, and to
 11 * permit persons to whom the Software is furnished to do so, subject to
 12 * the following conditions:
 13 *
 14 * The above copyright notice and this permission notice (including the
 15 * next paragraph) shall be included in all copies or substantial portions
 16 * of the Software.
 17 *
 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 25 *
 26 **************************************************************************/
 27/*
 28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 29 */
 30
 31#include "ttm/ttm_bo_driver.h"
 32#include "ttm/ttm_placement.h"
 
 
 
 33#include <linux/io.h>
 34#include <linux/highmem.h>
 35#include <linux/wait.h>
 36#include <linux/slab.h>
 37#include <linux/vmalloc.h>
 38#include <linux/module.h>
 
 39
 40void ttm_bo_free_old_node(struct ttm_buffer_object *bo)
 41{
 42	ttm_bo_mem_put(bo, &bo->mem);
 43}
 44
 45int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
 46		    bool evict, bool no_wait_reserve,
 47		    bool no_wait_gpu, struct ttm_mem_reg *new_mem)
 48{
 49	struct ttm_tt *ttm = bo->ttm;
 50	struct ttm_mem_reg *old_mem = &bo->mem;
 51	int ret;
 52
 53	if (old_mem->mem_type != TTM_PL_SYSTEM) {
 54		ttm_tt_unbind(ttm);
 55		ttm_bo_free_old_node(bo);
 56		ttm_flag_masked(&old_mem->placement, TTM_PL_FLAG_SYSTEM,
 57				TTM_PL_MASK_MEM);
 58		old_mem->mem_type = TTM_PL_SYSTEM;
 59	}
 60
 61	ret = ttm_tt_set_placement_caching(ttm, new_mem->placement);
 62	if (unlikely(ret != 0))
 63		return ret;
 64
 65	if (new_mem->mem_type != TTM_PL_SYSTEM) {
 66		ret = ttm_tt_bind(ttm, new_mem);
 67		if (unlikely(ret != 0))
 68			return ret;
 69	}
 70
 71	*old_mem = *new_mem;
 72	new_mem->mm_node = NULL;
 73
 74	return 0;
 75}
 76EXPORT_SYMBOL(ttm_bo_move_ttm);
 77
 78int ttm_mem_io_lock(struct ttm_mem_type_manager *man, bool interruptible)
 
 79{
 80	if (likely(man->io_reserve_fastpath))
 81		return 0;
 82
 83	if (interruptible)
 84		return mutex_lock_interruptible(&man->io_reserve_mutex);
 
 85
 86	mutex_lock(&man->io_reserve_mutex);
 87	return 0;
 88}
 89
 90void ttm_mem_io_unlock(struct ttm_mem_type_manager *man)
 
 91{
 92	if (likely(man->io_reserve_fastpath))
 93		return;
 94
 95	mutex_unlock(&man->io_reserve_mutex);
 96}
 97
 98static int ttm_mem_io_evict(struct ttm_mem_type_manager *man)
 99{
100	struct ttm_buffer_object *bo;
101
102	if (!man->use_io_reserve_lru || list_empty(&man->io_reserve_lru))
103		return -EAGAIN;
104
105	bo = list_first_entry(&man->io_reserve_lru,
106			      struct ttm_buffer_object,
107			      io_reserve_lru);
108	list_del_init(&bo->io_reserve_lru);
109	ttm_bo_unmap_virtual_locked(bo);
110
111	return 0;
 
112}
113
114static int ttm_mem_io_reserve(struct ttm_bo_device *bdev,
115			      struct ttm_mem_reg *mem)
 
 
 
 
 
 
 
 
 
 
 
 
116{
117	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
118	int ret = 0;
 
 
 
119
120	if (!bdev->driver->io_mem_reserve)
121		return 0;
122	if (likely(man->io_reserve_fastpath))
123		return bdev->driver->io_mem_reserve(bdev, mem);
124
125	if (bdev->driver->io_mem_reserve &&
126	    mem->bus.io_reserved_count++ == 0) {
127retry:
128		ret = bdev->driver->io_mem_reserve(bdev, mem);
129		if (ret == -EAGAIN) {
130			ret = ttm_mem_io_evict(man);
131			if (ret == 0)
132				goto retry;
 
 
 
 
 
133		}
134	}
135	return ret;
136}
137
138static void ttm_mem_io_free(struct ttm_bo_device *bdev,
139			    struct ttm_mem_reg *mem)
140{
141	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
142
143	if (likely(man->io_reserve_fastpath))
144		return;
145
146	if (bdev->driver->io_mem_reserve &&
147	    --mem->bus.io_reserved_count == 0 &&
148	    bdev->driver->io_mem_free)
149		bdev->driver->io_mem_free(bdev, mem);
150
151}
152
153int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo)
154{
155	struct ttm_mem_reg *mem = &bo->mem;
156	int ret;
157
158	if (!mem->bus.io_reserved_vm) {
159		struct ttm_mem_type_manager *man =
160			&bo->bdev->man[mem->mem_type];
161
162		ret = ttm_mem_io_reserve(bo->bdev, mem);
163		if (unlikely(ret != 0))
164			return ret;
165		mem->bus.io_reserved_vm = true;
166		if (man->use_io_reserve_lru)
167			list_add_tail(&bo->io_reserve_lru,
168				      &man->io_reserve_lru);
169	}
170	return 0;
171}
172
173void ttm_mem_io_free_vm(struct ttm_buffer_object *bo)
174{
175	struct ttm_mem_reg *mem = &bo->mem;
176
177	if (mem->bus.io_reserved_vm) {
178		mem->bus.io_reserved_vm = false;
179		list_del_init(&bo->io_reserve_lru);
180		ttm_mem_io_free(bo->bdev, mem);
181	}
182}
183
184int ttm_mem_reg_ioremap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem,
185			void **virtual)
186{
187	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
188	int ret;
189	void *addr;
190
191	*virtual = NULL;
192	(void) ttm_mem_io_lock(man, false);
193	ret = ttm_mem_io_reserve(bdev, mem);
194	ttm_mem_io_unlock(man);
195	if (ret || !mem->bus.is_iomem)
196		return ret;
197
198	if (mem->bus.addr) {
199		addr = mem->bus.addr;
200	} else {
201		if (mem->placement & TTM_PL_FLAG_WC)
202			addr = ioremap_wc(mem->bus.base + mem->bus.offset, mem->bus.size);
203		else
204			addr = ioremap_nocache(mem->bus.base + mem->bus.offset, mem->bus.size);
205		if (!addr) {
206			(void) ttm_mem_io_lock(man, false);
207			ttm_mem_io_free(bdev, mem);
208			ttm_mem_io_unlock(man);
209			return -ENOMEM;
210		}
211	}
212	*virtual = addr;
213	return 0;
214}
215
216void ttm_mem_reg_iounmap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem,
217			 void *virtual)
218{
219	struct ttm_mem_type_manager *man;
220
221	man = &bdev->man[mem->mem_type];
222
223	if (virtual && mem->bus.addr == NULL)
224		iounmap(virtual);
225	(void) ttm_mem_io_lock(man, false);
226	ttm_mem_io_free(bdev, mem);
227	ttm_mem_io_unlock(man);
228}
229
230static int ttm_copy_io_page(void *dst, void *src, unsigned long page)
231{
232	uint32_t *dstP =
233	    (uint32_t *) ((unsigned long)dst + (page << PAGE_SHIFT));
234	uint32_t *srcP =
235	    (uint32_t *) ((unsigned long)src + (page << PAGE_SHIFT));
236
237	int i;
238	for (i = 0; i < PAGE_SIZE / sizeof(uint32_t); ++i)
239		iowrite32(ioread32(srcP++), dstP++);
240	return 0;
241}
242
243static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
244				unsigned long page,
245				pgprot_t prot)
246{
247	struct page *d = ttm_tt_get_page(ttm, page);
248	void *dst;
249
250	if (!d)
251		return -ENOMEM;
252
253	src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
254
255#ifdef CONFIG_X86
256	dst = kmap_atomic_prot(d, prot);
257#else
258	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
259		dst = vmap(&d, 1, 0, prot);
260	else
261		dst = kmap(d);
262#endif
263	if (!dst)
264		return -ENOMEM;
265
266	memcpy_fromio(dst, src, PAGE_SIZE);
267
268#ifdef CONFIG_X86
269	kunmap_atomic(dst);
270#else
271	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
272		vunmap(dst);
273	else
274		kunmap(d);
275#endif
276
277	return 0;
278}
279
280static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
281				unsigned long page,
282				pgprot_t prot)
283{
284	struct page *s = ttm_tt_get_page(ttm, page);
285	void *src;
286
287	if (!s)
288		return -ENOMEM;
289
290	dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
291#ifdef CONFIG_X86
292	src = kmap_atomic_prot(s, prot);
293#else
294	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
295		src = vmap(&s, 1, 0, prot);
296	else
297		src = kmap(s);
298#endif
299	if (!src)
300		return -ENOMEM;
301
302	memcpy_toio(dst, src, PAGE_SIZE);
303
304#ifdef CONFIG_X86
305	kunmap_atomic(src);
306#else
307	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
308		vunmap(src);
309	else
310		kunmap(s);
311#endif
312
313	return 0;
314}
 
315
316int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
317		       bool evict, bool no_wait_reserve, bool no_wait_gpu,
318		       struct ttm_mem_reg *new_mem)
319{
320	struct ttm_bo_device *bdev = bo->bdev;
321	struct ttm_mem_type_manager *man = &bdev->man[new_mem->mem_type];
 
322	struct ttm_tt *ttm = bo->ttm;
323	struct ttm_mem_reg *old_mem = &bo->mem;
324	struct ttm_mem_reg old_copy = *old_mem;
325	void *old_iomap;
326	void *new_iomap;
327	int ret;
328	unsigned long i;
329	unsigned long page;
330	unsigned long add = 0;
331	int dir;
332
333	ret = ttm_mem_reg_ioremap(bdev, old_mem, &old_iomap);
334	if (ret)
335		return ret;
336	ret = ttm_mem_reg_ioremap(bdev, new_mem, &new_iomap);
337	if (ret)
338		goto out;
339
340	if (old_iomap == NULL && new_iomap == NULL)
341		goto out2;
342	if (old_iomap == NULL && ttm == NULL)
343		goto out2;
344
345	add = 0;
346	dir = 1;
347
348	if ((old_mem->mem_type == new_mem->mem_type) &&
349	    (new_mem->start < old_mem->start + old_mem->size)) {
350		dir = -1;
351		add = new_mem->num_pages - 1;
352	}
353
354	for (i = 0; i < new_mem->num_pages; ++i) {
355		page = i * dir + add;
356		if (old_iomap == NULL) {
357			pgprot_t prot = ttm_io_prot(old_mem->placement,
358						    PAGE_KERNEL);
359			ret = ttm_copy_ttm_io_page(ttm, new_iomap, page,
360						   prot);
361		} else if (new_iomap == NULL) {
362			pgprot_t prot = ttm_io_prot(new_mem->placement,
363						    PAGE_KERNEL);
364			ret = ttm_copy_io_ttm_page(ttm, old_iomap, page,
365						   prot);
366		} else
367			ret = ttm_copy_io_page(new_iomap, old_iomap, page);
368		if (ret)
369			goto out1;
370	}
371	mb();
372out2:
373	old_copy = *old_mem;
374	*old_mem = *new_mem;
375	new_mem->mm_node = NULL;
376
377	if ((man->flags & TTM_MEMTYPE_FLAG_FIXED) && (ttm != NULL)) {
378		ttm_tt_unbind(ttm);
379		ttm_tt_destroy(ttm);
380		bo->ttm = NULL;
381	}
382
383out1:
384	ttm_mem_reg_iounmap(bdev, old_mem, new_iomap);
385out:
386	ttm_mem_reg_iounmap(bdev, &old_copy, old_iomap);
387	ttm_bo_mem_put(bo, &old_copy);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
388	return ret;
389}
390EXPORT_SYMBOL(ttm_bo_move_memcpy);
391
392static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
393{
394	kfree(bo);
 
 
 
 
395}
396
397/**
398 * ttm_buffer_object_transfer
399 *
400 * @bo: A pointer to a struct ttm_buffer_object.
401 * @new_obj: A pointer to a pointer to a newly created ttm_buffer_object,
402 * holding the data of @bo with the old placement.
403 *
404 * This is a utility function that may be called after an accelerated move
405 * has been scheduled. A new buffer object is created as a placeholder for
406 * the old data while it's being copied. When that buffer object is idle,
407 * it can be destroyed, releasing the space of the old placement.
408 * Returns:
409 * !0: Failure.
410 */
411
412static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
413				      struct ttm_buffer_object **new_obj)
414{
415	struct ttm_buffer_object *fbo;
416	struct ttm_bo_device *bdev = bo->bdev;
417	struct ttm_bo_driver *driver = bdev->driver;
418
419	fbo = kzalloc(sizeof(*fbo), GFP_KERNEL);
420	if (!fbo)
421		return -ENOMEM;
422
423	*fbo = *bo;
 
 
 
424
425	/**
426	 * Fix up members that we shouldn't copy directly:
427	 * TODO: Explicit member copy would probably be better here.
428	 */
429
430	init_waitqueue_head(&fbo->event_queue);
431	INIT_LIST_HEAD(&fbo->ddestroy);
432	INIT_LIST_HEAD(&fbo->lru);
433	INIT_LIST_HEAD(&fbo->swap);
434	INIT_LIST_HEAD(&fbo->io_reserve_lru);
435	fbo->vm_node = NULL;
436	atomic_set(&fbo->cpu_writers, 0);
437
438	fbo->sync_obj = driver->sync_obj_ref(bo->sync_obj);
439	kref_init(&fbo->list_kref);
440	kref_init(&fbo->kref);
441	fbo->destroy = &ttm_transfered_destroy;
 
 
 
 
442
443	*new_obj = fbo;
 
 
444	return 0;
445}
446
447pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp)
 
448{
449#if defined(__i386__) || defined(__x86_64__)
450	if (caching_flags & TTM_PL_FLAG_WC)
451		tmp = pgprot_writecombine(tmp);
452	else if (boot_cpu_data.x86 > 3)
453		tmp = pgprot_noncached(tmp);
454
455#elif defined(__powerpc__)
456	if (!(caching_flags & TTM_PL_FLAG_CACHED)) {
457		pgprot_val(tmp) |= _PAGE_NO_CACHE;
458		if (caching_flags & TTM_PL_FLAG_UNCACHED)
459			pgprot_val(tmp) |= _PAGE_GUARDED;
460	}
461#endif
462#if defined(__ia64__)
463	if (caching_flags & TTM_PL_FLAG_WC)
464		tmp = pgprot_writecombine(tmp);
465	else
466		tmp = pgprot_noncached(tmp);
467#endif
468#if defined(__sparc__)
469	if (!(caching_flags & TTM_PL_FLAG_CACHED))
470		tmp = pgprot_noncached(tmp);
471#endif
472	return tmp;
473}
474EXPORT_SYMBOL(ttm_io_prot);
475
476static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
477			  unsigned long offset,
478			  unsigned long size,
479			  struct ttm_bo_kmap_obj *map)
480{
481	struct ttm_mem_reg *mem = &bo->mem;
482
483	if (bo->mem.bus.addr) {
484		map->bo_kmap_type = ttm_bo_map_premapped;
485		map->virtual = (void *)(((u8 *)bo->mem.bus.addr) + offset);
486	} else {
 
 
487		map->bo_kmap_type = ttm_bo_map_iomap;
488		if (mem->placement & TTM_PL_FLAG_WC)
489			map->virtual = ioremap_wc(bo->mem.bus.base + bo->mem.bus.offset + offset,
490						  size);
 
 
 
491		else
492			map->virtual = ioremap_nocache(bo->mem.bus.base + bo->mem.bus.offset + offset,
493						       size);
494	}
495	return (!map->virtual) ? -ENOMEM : 0;
496}
497
498static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
499			   unsigned long start_page,
500			   unsigned long num_pages,
501			   struct ttm_bo_kmap_obj *map)
502{
503	struct ttm_mem_reg *mem = &bo->mem; pgprot_t prot;
 
 
 
 
504	struct ttm_tt *ttm = bo->ttm;
505	struct page *d;
506	int i;
507
508	BUG_ON(!ttm);
509	if (num_pages == 1 && (mem->placement & TTM_PL_FLAG_CACHED)) {
 
 
 
 
 
510		/*
511		 * We're mapping a single page, and the desired
512		 * page protection is consistent with the bo.
513		 */
514
515		map->bo_kmap_type = ttm_bo_map_kmap;
516		map->page = ttm_tt_get_page(ttm, start_page);
517		map->virtual = kmap(map->page);
518	} else {
519	    /*
520	     * Populate the part we're mapping;
521	     */
522		for (i = start_page; i < start_page + num_pages; ++i) {
523			d = ttm_tt_get_page(ttm, i);
524			if (!d)
525				return -ENOMEM;
526		}
527
528		/*
529		 * We need to use vmap to get the desired page protection
530		 * or to make the buffer object look contiguous.
531		 */
532		prot = (mem->placement & TTM_PL_FLAG_CACHED) ?
533			PAGE_KERNEL :
534			ttm_io_prot(mem->placement, PAGE_KERNEL);
535		map->bo_kmap_type = ttm_bo_map_vmap;
536		map->virtual = vmap(ttm->pages + start_page, num_pages,
537				    0, prot);
538	}
539	return (!map->virtual) ? -ENOMEM : 0;
540}
541
542int ttm_bo_kmap(struct ttm_buffer_object *bo,
543		unsigned long start_page, unsigned long num_pages,
544		struct ttm_bo_kmap_obj *map)
545{
546	struct ttm_mem_type_manager *man =
547		&bo->bdev->man[bo->mem.mem_type];
548	unsigned long offset, size;
549	int ret;
550
551	BUG_ON(!list_empty(&bo->swap));
552	map->virtual = NULL;
553	map->bo = bo;
554	if (num_pages > bo->num_pages)
555		return -EINVAL;
556	if (start_page > bo->num_pages)
557		return -EINVAL;
558#if 0
559	if (num_pages > 1 && !DRM_SUSER(DRM_CURPROC))
560		return -EPERM;
561#endif
562	(void) ttm_mem_io_lock(man, false);
563	ret = ttm_mem_io_reserve(bo->bdev, &bo->mem);
564	ttm_mem_io_unlock(man);
565	if (ret)
566		return ret;
567	if (!bo->mem.bus.is_iomem) {
568		return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
569	} else {
570		offset = start_page << PAGE_SHIFT;
571		size = num_pages << PAGE_SHIFT;
572		return ttm_bo_ioremap(bo, offset, size, map);
573	}
574}
575EXPORT_SYMBOL(ttm_bo_kmap);
576
577void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
578{
579	struct ttm_buffer_object *bo = map->bo;
580	struct ttm_mem_type_manager *man =
581		&bo->bdev->man[bo->mem.mem_type];
582
583	if (!map->virtual)
584		return;
585	switch (map->bo_kmap_type) {
586	case ttm_bo_map_iomap:
587		iounmap(map->virtual);
588		break;
589	case ttm_bo_map_vmap:
590		vunmap(map->virtual);
591		break;
592	case ttm_bo_map_kmap:
593		kunmap(map->page);
594		break;
595	case ttm_bo_map_premapped:
596		break;
597	default:
598		BUG();
599	}
600	(void) ttm_mem_io_lock(man, false);
601	ttm_mem_io_free(map->bo->bdev, &map->bo->mem);
602	ttm_mem_io_unlock(man);
603	map->virtual = NULL;
604	map->page = NULL;
605}
606EXPORT_SYMBOL(ttm_bo_kunmap);
607
608int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
609			      void *sync_obj,
610			      void *sync_obj_arg,
611			      bool evict, bool no_wait_reserve,
612			      bool no_wait_gpu,
613			      struct ttm_mem_reg *new_mem)
614{
615	struct ttm_bo_device *bdev = bo->bdev;
616	struct ttm_bo_driver *driver = bdev->driver;
617	struct ttm_mem_type_manager *man = &bdev->man[new_mem->mem_type];
618	struct ttm_mem_reg *old_mem = &bo->mem;
619	int ret;
620	struct ttm_buffer_object *ghost_obj;
621	void *tmp_obj = NULL;
622
623	spin_lock(&bdev->fence_lock);
624	if (bo->sync_obj) {
625		tmp_obj = bo->sync_obj;
626		bo->sync_obj = NULL;
627	}
628	bo->sync_obj = driver->sync_obj_ref(sync_obj);
629	bo->sync_obj_arg = sync_obj_arg;
630	if (evict) {
631		ret = ttm_bo_wait(bo, false, false, false);
632		spin_unlock(&bdev->fence_lock);
633		if (tmp_obj)
634			driver->sync_obj_unref(&tmp_obj);
635		if (ret)
636			return ret;
637
638		if ((man->flags & TTM_MEMTYPE_FLAG_FIXED) &&
639		    (bo->ttm != NULL)) {
640			ttm_tt_unbind(bo->ttm);
641			ttm_tt_destroy(bo->ttm);
642			bo->ttm = NULL;
643		}
644		ttm_bo_free_old_node(bo);
645	} else {
646		/**
647		 * This should help pipeline ordinary buffer moves.
648		 *
649		 * Hang old buffer memory on a new buffer object,
650		 * and leave it to be released when the GPU
651		 * operation has completed.
652		 */
653
654		set_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags);
655		spin_unlock(&bdev->fence_lock);
656		if (tmp_obj)
657			driver->sync_obj_unref(&tmp_obj);
 
 
 
 
 
 
 
 
658
659		ret = ttm_buffer_object_transfer(bo, &ghost_obj);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
660		if (ret)
661			return ret;
662
663		/**
664		 * If we're not moving to fixed memory, the TTM object
665		 * needs to stay alive. Otherwhise hang it on the ghost
666		 * bo to be unbound and destroyed.
667		 */
 
 
 
 
668
669		if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED))
670			ghost_obj->ttm = NULL;
671		else
672			bo->ttm = NULL;
 
 
 
 
 
 
673
674		ttm_bo_unreserve(ghost_obj);
675		ttm_bo_unref(&ghost_obj);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
676	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
677
678	*old_mem = *new_mem;
679	new_mem->mm_node = NULL;
 
 
680
681	return 0;
682}
683EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
v5.14.15
  1/* SPDX-License-Identifier: GPL-2.0 OR MIT */
  2/**************************************************************************
  3 *
  4 * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
  5 * All Rights Reserved.
  6 *
  7 * Permission is hereby granted, free of charge, to any person obtaining a
  8 * copy of this software and associated documentation files (the
  9 * "Software"), to deal in the Software without restriction, including
 10 * without limitation the rights to use, copy, modify, merge, publish,
 11 * distribute, sub license, and/or sell copies of the Software, and to
 12 * permit persons to whom the Software is furnished to do so, subject to
 13 * the following conditions:
 14 *
 15 * The above copyright notice and this permission notice (including the
 16 * next paragraph) shall be included in all copies or substantial portions
 17 * of the Software.
 18 *
 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 26 *
 27 **************************************************************************/
 28/*
 29 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 30 */
 31
 32#include <drm/ttm/ttm_bo_driver.h>
 33#include <drm/ttm/ttm_placement.h>
 34#include <drm/drm_cache.h>
 35#include <drm/drm_vma_manager.h>
 36#include <linux/dma-buf-map.h>
 37#include <linux/io.h>
 38#include <linux/highmem.h>
 39#include <linux/wait.h>
 40#include <linux/slab.h>
 41#include <linux/vmalloc.h>
 42#include <linux/module.h>
 43#include <linux/dma-resv.h>
 44
 45struct ttm_transfer_obj {
 46	struct ttm_buffer_object base;
 47	struct ttm_buffer_object *bo;
 48};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 49
 50int ttm_mem_io_reserve(struct ttm_device *bdev,
 51		       struct ttm_resource *mem)
 52{
 53	if (mem->bus.offset || mem->bus.addr)
 54		return 0;
 55
 56	mem->bus.is_iomem = false;
 57	if (!bdev->funcs->io_mem_reserve)
 58		return 0;
 59
 60	return bdev->funcs->io_mem_reserve(bdev, mem);
 
 61}
 62
 63void ttm_mem_io_free(struct ttm_device *bdev,
 64		     struct ttm_resource *mem)
 65{
 66	if (!mem)
 67		return;
 68
 69	if (!mem->bus.offset && !mem->bus.addr)
 70		return;
 
 
 
 
 
 
 
 71
 72	if (bdev->funcs->io_mem_free)
 73		bdev->funcs->io_mem_free(bdev, mem);
 
 
 
 74
 75	mem->bus.offset = 0;
 76	mem->bus.addr = NULL;
 77}
 78
 79/**
 80 * ttm_move_memcpy - Helper to perform a memcpy ttm move operation.
 81 * @bo: The struct ttm_buffer_object.
 82 * @new_mem: The struct ttm_resource we're moving to (copy destination).
 83 * @new_iter: A struct ttm_kmap_iter representing the destination resource.
 84 * @src_iter: A struct ttm_kmap_iter representing the source resource.
 85 *
 86 * This function is intended to be able to move out async under a
 87 * dma-fence if desired.
 88 */
 89void ttm_move_memcpy(struct ttm_buffer_object *bo,
 90		     u32 num_pages,
 91		     struct ttm_kmap_iter *dst_iter,
 92		     struct ttm_kmap_iter *src_iter)
 93{
 94	const struct ttm_kmap_iter_ops *dst_ops = dst_iter->ops;
 95	const struct ttm_kmap_iter_ops *src_ops = src_iter->ops;
 96	struct ttm_tt *ttm = bo->ttm;
 97	struct dma_buf_map src_map, dst_map;
 98	pgoff_t i;
 99
100	/* Single TTM move. NOP */
101	if (dst_ops->maps_tt && src_ops->maps_tt)
102		return;
 
103
104	/* Don't move nonexistent data. Clear destination instead. */
105	if (src_ops->maps_tt && (!ttm || !ttm_tt_is_populated(ttm))) {
106		if (ttm && !(ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC))
107			return;
108
109		for (i = 0; i < num_pages; ++i) {
110			dst_ops->map_local(dst_iter, &dst_map, i);
111			if (dst_map.is_iomem)
112				memset_io(dst_map.vaddr_iomem, 0, PAGE_SIZE);
113			else
114				memset(dst_map.vaddr, 0, PAGE_SIZE);
115			if (dst_ops->unmap_local)
116				dst_ops->unmap_local(dst_iter, &dst_map);
117		}
 
 
 
 
 
 
 
 
 
 
118		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
119	}
 
 
120
121	for (i = 0; i < num_pages; ++i) {
122		dst_ops->map_local(dst_iter, &dst_map, i);
123		src_ops->map_local(src_iter, &src_map, i);
124
125		drm_memcpy_from_wc(&dst_map, &src_map, PAGE_SIZE);
 
 
 
 
 
126
127		if (src_ops->unmap_local)
128			src_ops->unmap_local(src_iter, &src_map);
129		if (dst_ops->unmap_local)
130			dst_ops->unmap_local(dst_iter, &dst_map);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
131	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
132}
133EXPORT_SYMBOL(ttm_move_memcpy);
134
135int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
136		       struct ttm_operation_ctx *ctx,
137		       struct ttm_resource *dst_mem)
138{
139	struct ttm_device *bdev = bo->bdev;
140	struct ttm_resource_manager *dst_man =
141		ttm_manager_type(bo->bdev, dst_mem->mem_type);
142	struct ttm_tt *ttm = bo->ttm;
143	struct ttm_resource *src_mem = bo->resource;
144	struct ttm_resource_manager *src_man =
145		ttm_manager_type(bdev, src_mem->mem_type);
146	union {
147		struct ttm_kmap_iter_tt tt;
148		struct ttm_kmap_iter_linear_io io;
149	} _dst_iter, _src_iter;
150	struct ttm_kmap_iter *dst_iter, *src_iter;
151	int ret = 0;
 
 
 
 
 
 
 
152
153	if (ttm && ((ttm->page_flags & TTM_PAGE_FLAG_SWAPPED) ||
154		    dst_man->use_tt)) {
155		ret = ttm_tt_populate(bdev, ttm, ctx);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
156		if (ret)
157			return ret;
 
 
 
 
 
 
 
 
 
 
 
158	}
159
160	dst_iter = ttm_kmap_iter_linear_io_init(&_dst_iter.io, bdev, dst_mem);
161	if (PTR_ERR(dst_iter) == -EINVAL && dst_man->use_tt)
162		dst_iter = ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm);
163	if (IS_ERR(dst_iter))
164		return PTR_ERR(dst_iter);
165
166	src_iter = ttm_kmap_iter_linear_io_init(&_src_iter.io, bdev, src_mem);
167	if (PTR_ERR(src_iter) == -EINVAL && src_man->use_tt)
168		src_iter = ttm_kmap_iter_tt_init(&_src_iter.tt, bo->ttm);
169	if (IS_ERR(src_iter)) {
170		ret = PTR_ERR(src_iter);
171		goto out_src_iter;
172	}
173
174	ttm_move_memcpy(bo, dst_mem->num_pages, dst_iter, src_iter);
175
176	if (!src_iter->ops->maps_tt)
177		ttm_kmap_iter_linear_io_fini(&_src_iter.io, bdev, src_mem);
178	ttm_bo_move_sync_cleanup(bo, dst_mem);
179
180out_src_iter:
181	if (!dst_iter->ops->maps_tt)
182		ttm_kmap_iter_linear_io_fini(&_dst_iter.io, bdev, dst_mem);
183
184	return ret;
185}
186EXPORT_SYMBOL(ttm_bo_move_memcpy);
187
188static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
189{
190	struct ttm_transfer_obj *fbo;
191
192	fbo = container_of(bo, struct ttm_transfer_obj, base);
193	ttm_bo_put(fbo->bo);
194	kfree(fbo);
195}
196
197/**
198 * ttm_buffer_object_transfer
199 *
200 * @bo: A pointer to a struct ttm_buffer_object.
201 * @new_obj: A pointer to a pointer to a newly created ttm_buffer_object,
202 * holding the data of @bo with the old placement.
203 *
204 * This is a utility function that may be called after an accelerated move
205 * has been scheduled. A new buffer object is created as a placeholder for
206 * the old data while it's being copied. When that buffer object is idle,
207 * it can be destroyed, releasing the space of the old placement.
208 * Returns:
209 * !0: Failure.
210 */
211
212static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
213				      struct ttm_buffer_object **new_obj)
214{
215	struct ttm_transfer_obj *fbo;
216	int ret;
 
217
218	fbo = kmalloc(sizeof(*fbo), GFP_KERNEL);
219	if (!fbo)
220		return -ENOMEM;
221
222	fbo->base = *bo;
223
224	ttm_bo_get(bo);
225	fbo->bo = bo;
226
227	/**
228	 * Fix up members that we shouldn't copy directly:
229	 * TODO: Explicit member copy would probably be better here.
230	 */
231
232	atomic_inc(&ttm_glob.bo_count);
233	INIT_LIST_HEAD(&fbo->base.ddestroy);
234	INIT_LIST_HEAD(&fbo->base.lru);
235	fbo->base.moving = NULL;
236	drm_vma_node_reset(&fbo->base.base.vma_node);
237
238	kref_init(&fbo->base.kref);
239	fbo->base.destroy = &ttm_transfered_destroy;
240	fbo->base.pin_count = 0;
241	if (bo->type != ttm_bo_type_sg)
242		fbo->base.base.resv = &fbo->base.base._resv;
243
244	dma_resv_init(&fbo->base.base._resv);
245	fbo->base.base.dev = NULL;
246	ret = dma_resv_trylock(&fbo->base.base._resv);
247	WARN_ON(!ret);
248
249	ttm_bo_move_to_lru_tail_unlocked(&fbo->base);
250
251	*new_obj = &fbo->base;
252	return 0;
253}
254
255pgprot_t ttm_io_prot(struct ttm_buffer_object *bo, struct ttm_resource *res,
256		     pgprot_t tmp)
257{
258	struct ttm_resource_manager *man;
259	enum ttm_caching caching;
260
261	man = ttm_manager_type(bo->bdev, res->mem_type);
262	caching = man->use_tt ? bo->ttm->caching : res->bus.caching;
263
264	return ttm_prot_from_caching(caching, tmp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
265}
266EXPORT_SYMBOL(ttm_io_prot);
267
268static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
269			  unsigned long offset,
270			  unsigned long size,
271			  struct ttm_bo_kmap_obj *map)
272{
273	struct ttm_resource *mem = bo->resource;
274
275	if (bo->resource->bus.addr) {
276		map->bo_kmap_type = ttm_bo_map_premapped;
277		map->virtual = ((u8 *)bo->resource->bus.addr) + offset;
278	} else {
279		resource_size_t res = bo->resource->bus.offset + offset;
280
281		map->bo_kmap_type = ttm_bo_map_iomap;
282		if (mem->bus.caching == ttm_write_combined)
283			map->virtual = ioremap_wc(res, size);
284#ifdef CONFIG_X86
285		else if (mem->bus.caching == ttm_cached)
286			map->virtual = ioremap_cache(res, size);
287#endif
288		else
289			map->virtual = ioremap(res, size);
 
290	}
291	return (!map->virtual) ? -ENOMEM : 0;
292}
293
294static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
295			   unsigned long start_page,
296			   unsigned long num_pages,
297			   struct ttm_bo_kmap_obj *map)
298{
299	struct ttm_resource *mem = bo->resource;
300	struct ttm_operation_ctx ctx = {
301		.interruptible = false,
302		.no_wait_gpu = false
303	};
304	struct ttm_tt *ttm = bo->ttm;
305	pgprot_t prot;
306	int ret;
307
308	BUG_ON(!ttm);
309
310	ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
311	if (ret)
312		return ret;
313
314	if (num_pages == 1 && ttm->caching == ttm_cached) {
315		/*
316		 * We're mapping a single page, and the desired
317		 * page protection is consistent with the bo.
318		 */
319
320		map->bo_kmap_type = ttm_bo_map_kmap;
321		map->page = ttm->pages[start_page];
322		map->virtual = kmap(map->page);
323	} else {
 
 
 
 
 
 
 
 
 
324		/*
325		 * We need to use vmap to get the desired page protection
326		 * or to make the buffer object look contiguous.
327		 */
328		prot = ttm_io_prot(bo, mem, PAGE_KERNEL);
 
 
329		map->bo_kmap_type = ttm_bo_map_vmap;
330		map->virtual = vmap(ttm->pages + start_page, num_pages,
331				    0, prot);
332	}
333	return (!map->virtual) ? -ENOMEM : 0;
334}
335
336int ttm_bo_kmap(struct ttm_buffer_object *bo,
337		unsigned long start_page, unsigned long num_pages,
338		struct ttm_bo_kmap_obj *map)
339{
 
 
340	unsigned long offset, size;
341	int ret;
342
 
343	map->virtual = NULL;
344	map->bo = bo;
345	if (num_pages > bo->resource->num_pages)
346		return -EINVAL;
347	if ((start_page + num_pages) > bo->resource->num_pages)
348		return -EINVAL;
349
350	ret = ttm_mem_io_reserve(bo->bdev, bo->resource);
 
 
 
 
 
351	if (ret)
352		return ret;
353	if (!bo->resource->bus.is_iomem) {
354		return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
355	} else {
356		offset = start_page << PAGE_SHIFT;
357		size = num_pages << PAGE_SHIFT;
358		return ttm_bo_ioremap(bo, offset, size, map);
359	}
360}
361EXPORT_SYMBOL(ttm_bo_kmap);
362
363void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
364{
 
 
 
 
365	if (!map->virtual)
366		return;
367	switch (map->bo_kmap_type) {
368	case ttm_bo_map_iomap:
369		iounmap(map->virtual);
370		break;
371	case ttm_bo_map_vmap:
372		vunmap(map->virtual);
373		break;
374	case ttm_bo_map_kmap:
375		kunmap(map->page);
376		break;
377	case ttm_bo_map_premapped:
378		break;
379	default:
380		BUG();
381	}
382	ttm_mem_io_free(map->bo->bdev, map->bo->resource);
 
 
383	map->virtual = NULL;
384	map->page = NULL;
385}
386EXPORT_SYMBOL(ttm_bo_kunmap);
387
388int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
389{
390	struct ttm_resource *mem = bo->resource;
 
 
 
 
 
 
 
 
391	int ret;
 
 
392
393	ret = ttm_mem_io_reserve(bo->bdev, mem);
394	if (ret)
395		return ret;
 
 
 
 
 
 
 
 
 
 
 
396
397	if (mem->bus.is_iomem) {
398		void __iomem *vaddr_iomem;
 
 
 
 
 
 
 
 
 
 
 
 
 
399
400		if (mem->bus.addr)
401			vaddr_iomem = (void __iomem *)mem->bus.addr;
402		else if (mem->bus.caching == ttm_write_combined)
403			vaddr_iomem = ioremap_wc(mem->bus.offset,
404						 bo->base.size);
405#ifdef CONFIG_X86
406		else if (mem->bus.caching == ttm_cached)
407			vaddr_iomem = ioremap_cache(mem->bus.offset,
408						  bo->base.size);
409#endif
410		else
411			vaddr_iomem = ioremap(mem->bus.offset, bo->base.size);
412
413		if (!vaddr_iomem)
414			return -ENOMEM;
415
416		dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
417
418	} else {
419		struct ttm_operation_ctx ctx = {
420			.interruptible = false,
421			.no_wait_gpu = false
422		};
423		struct ttm_tt *ttm = bo->ttm;
424		pgprot_t prot;
425		void *vaddr;
426
427		ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
428		if (ret)
429			return ret;
430
431		/*
432		 * We need to use vmap to get the desired page protection
433		 * or to make the buffer object look contiguous.
 
434		 */
435		prot = ttm_io_prot(bo, mem, PAGE_KERNEL);
436		vaddr = vmap(ttm->pages, ttm->num_pages, 0, prot);
437		if (!vaddr)
438			return -ENOMEM;
439
440		dma_buf_map_set_vaddr(map, vaddr);
441	}
442
443	return 0;
444}
445EXPORT_SYMBOL(ttm_bo_vmap);
446
447void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
448{
449	struct ttm_resource *mem = bo->resource;
450
451	if (dma_buf_map_is_null(map))
452		return;
453
454	if (!map->is_iomem)
455		vunmap(map->vaddr);
456	else if (!mem->bus.addr)
457		iounmap(map->vaddr_iomem);
458	dma_buf_map_clear(map);
459
460	ttm_mem_io_free(bo->bdev, bo->resource);
461}
462EXPORT_SYMBOL(ttm_bo_vunmap);
463
464static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
465				 bool dst_use_tt)
466{
467	int ret;
468	ret = ttm_bo_wait(bo, false, false);
469	if (ret)
470		return ret;
471
472	if (!dst_use_tt)
473		ttm_bo_tt_destroy(bo);
474	ttm_resource_free(bo, &bo->resource);
475	return 0;
476}
477
478static int ttm_bo_move_to_ghost(struct ttm_buffer_object *bo,
479				struct dma_fence *fence,
480				bool dst_use_tt)
481{
482	struct ttm_buffer_object *ghost_obj;
483	int ret;
484
485	/**
486	 * This should help pipeline ordinary buffer moves.
487	 *
488	 * Hang old buffer memory on a new buffer object,
489	 * and leave it to be released when the GPU
490	 * operation has completed.
491	 */
492
493	dma_fence_put(bo->moving);
494	bo->moving = dma_fence_get(fence);
495
496	ret = ttm_buffer_object_transfer(bo, &ghost_obj);
497	if (ret)
498		return ret;
499
500	dma_resv_add_excl_fence(&ghost_obj->base._resv, fence);
501
502	/**
503	 * If we're not moving to fixed memory, the TTM object
504	 * needs to stay alive. Otherwhise hang it on the ghost
505	 * bo to be unbound and destroyed.
506	 */
507
508	if (dst_use_tt)
509		ghost_obj->ttm = NULL;
510	else
511		bo->ttm = NULL;
512	bo->resource = NULL;
513
514	dma_resv_unlock(&ghost_obj->base._resv);
515	ttm_bo_put(ghost_obj);
516	return 0;
517}
518
519static void ttm_bo_move_pipeline_evict(struct ttm_buffer_object *bo,
520				       struct dma_fence *fence)
521{
522	struct ttm_device *bdev = bo->bdev;
523	struct ttm_resource_manager *from;
524
525	from = ttm_manager_type(bdev, bo->resource->mem_type);
526
527	/**
528	 * BO doesn't have a TTM we need to bind/unbind. Just remember
529	 * this eviction and free up the allocation
530	 */
531	spin_lock(&from->move_lock);
532	if (!from->move || dma_fence_is_later(fence, from->move)) {
533		dma_fence_put(from->move);
534		from->move = dma_fence_get(fence);
535	}
536	spin_unlock(&from->move_lock);
537
538	ttm_resource_free(bo, &bo->resource);
539
540	dma_fence_put(bo->moving);
541	bo->moving = dma_fence_get(fence);
542}
543
544int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
545			      struct dma_fence *fence,
546			      bool evict,
547			      bool pipeline,
548			      struct ttm_resource *new_mem)
549{
550	struct ttm_device *bdev = bo->bdev;
551	struct ttm_resource_manager *from = ttm_manager_type(bdev, bo->resource->mem_type);
552	struct ttm_resource_manager *man = ttm_manager_type(bdev, new_mem->mem_type);
553	int ret = 0;
554
555	dma_resv_add_excl_fence(bo->base.resv, fence);
556	if (!evict)
557		ret = ttm_bo_move_to_ghost(bo, fence, man->use_tt);
558	else if (!from->use_tt && pipeline)
559		ttm_bo_move_pipeline_evict(bo, fence);
560	else
561		ret = ttm_bo_wait_free_node(bo, man->use_tt);
562
563	if (ret)
564		return ret;
565
566	ttm_bo_assign_mem(bo, new_mem);
567
568	return 0;
569}
570EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
571
572/**
573 * ttm_bo_pipeline_gutting - purge the contents of a bo
574 * @bo: The buffer object
575 *
576 * Purge the contents of a bo, async if the bo is not idle.
577 * After a successful call, the bo is left unpopulated in
578 * system placement. The function may wait uninterruptible
579 * for idle on OOM.
580 *
581 * Return: 0 if successful, negative error code on failure.
582 */
583int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
584{
585	static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
586	struct ttm_buffer_object *ghost;
587	struct ttm_resource *sys_res;
588	struct ttm_tt *ttm;
589	int ret;
590
591	ret = ttm_resource_alloc(bo, &sys_mem, &sys_res);
592	if (ret)
593		return ret;
594
595	/* If already idle, no need for ghost object dance. */
596	ret = ttm_bo_wait(bo, false, true);
597	if (ret != -EBUSY) {
598		if (!bo->ttm) {
599			/* See comment below about clearing. */
600			ret = ttm_tt_create(bo, true);
601			if (ret)
602				goto error_free_sys_mem;
603		} else {
604			ttm_tt_unpopulate(bo->bdev, bo->ttm);
605			if (bo->type == ttm_bo_type_device)
606				ttm_tt_mark_for_clear(bo->ttm);
607		}
608		ttm_resource_free(bo, &bo->resource);
609		ttm_bo_assign_mem(bo, sys_res);
610		return 0;
611	}
612
613	/*
614	 * We need an unpopulated ttm_tt after giving our current one,
615	 * if any, to the ghost object. And we can't afford to fail
616	 * creating one *after* the operation. If the bo subsequently gets
617	 * resurrected, make sure it's cleared (if ttm_bo_type_device)
618	 * to avoid leaking sensitive information to user-space.
619	 */
620
621	ttm = bo->ttm;
622	bo->ttm = NULL;
623	ret = ttm_tt_create(bo, true);
624	swap(bo->ttm, ttm);
625	if (ret)
626		goto error_free_sys_mem;
627
628	ret = ttm_buffer_object_transfer(bo, &ghost);
629	if (ret)
630		goto error_destroy_tt;
631
632	ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv);
633	/* Last resort, wait for the BO to be idle when we are OOM */
634	if (ret)
635		ttm_bo_wait(bo, false, false);
636
637	dma_resv_unlock(&ghost->base._resv);
638	ttm_bo_put(ghost);
639	bo->ttm = ttm;
640	bo->resource = NULL;
641	ttm_bo_assign_mem(bo, sys_res);
642	return 0;
643
644error_destroy_tt:
645	ttm_tt_destroy(bo->bdev, ttm);
646
647error_free_sys_mem:
648	ttm_resource_free(bo, &sys_res);
649	return ret;
650}