1/*
  2 * SPDX-License-Identifier: MIT
  3 *
  4 * Copyright © 2016 Intel Corporation
  5 */
  6
  7#include "i915_scatterlist.h"
  8
  9#include "huge_gem_object.h"
 10
 11static void huge_free_pages(struct drm_i915_gem_object *obj,
 12			    struct sg_table *pages)
 13{
 14	unsigned long nreal = obj->scratch / PAGE_SIZE;
 15	struct sgt_iter sgt_iter;
 16	struct page *page;
 17
 18	for_each_sgt_page(page, sgt_iter, pages) {
 19		__free_page(page);
 20		if (!--nreal)
 21			break;
 22	}
 23
 24	sg_free_table(pages);
 25	kfree(pages);
 26}
 27
 28static int huge_get_pages(struct drm_i915_gem_object *obj)
 29{
 30#define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_RETRY_MAYFAIL)
 31	const unsigned long nreal = obj->scratch / PAGE_SIZE;
 32	unsigned int npages; /* restricted by sg_alloc_table */
 33	struct scatterlist *sg, *src, *end;
 34	struct sg_table *pages;
 35	unsigned long n;
 36
 37	if (overflows_type(obj->base.size / PAGE_SIZE, npages))
 38		return -E2BIG;
 39
 40	npages = obj->base.size / PAGE_SIZE;
 41	pages = kmalloc(sizeof(*pages), GFP);
 42	if (!pages)
 43		return -ENOMEM;
 44
 45	if (sg_alloc_table(pages, npages, GFP)) {
 46		kfree(pages);
 47		return -ENOMEM;
 48	}
 49
 50	sg = pages->sgl;
 51	for (n = 0; n < nreal; n++) {
 52		struct page *page;
 53
 54		page = alloc_page(GFP | __GFP_HIGHMEM);
 55		if (!page) {
 56			sg_mark_end(sg);
 57			goto err;
 58		}
 59
 60		sg_set_page(sg, page, PAGE_SIZE, 0);
 61		sg = __sg_next(sg);
 62	}
 63	if (nreal < npages) {
 64		for (end = sg, src = pages->sgl; sg; sg = __sg_next(sg)) {
 65			sg_set_page(sg, sg_page(src), PAGE_SIZE, 0);
 66			src = __sg_next(src);
 67			if (src == end)
 68				src = pages->sgl;
 69		}
 70	}
 71
 72	if (i915_gem_gtt_prepare_pages(obj, pages))
 73		goto err;
 74
 75	__i915_gem_object_set_pages(obj, pages);
 76
 77	return 0;
 78
 79err:
 80	huge_free_pages(obj, pages);
 81	return -ENOMEM;
 82#undef GFP
 83}
 84
 85static void huge_put_pages(struct drm_i915_gem_object *obj,
 86			   struct sg_table *pages)
 87{
 88	i915_gem_gtt_finish_pages(obj, pages);
 89	huge_free_pages(obj, pages);
 90
 91	obj->mm.dirty = false;
 92}
 93
 94static const struct drm_i915_gem_object_ops huge_ops = {
 95	.name = "huge-gem",
 96	.get_pages = huge_get_pages,
 97	.put_pages = huge_put_pages,
 98};
 99
100struct drm_i915_gem_object *
101huge_gem_object(struct drm_i915_private *i915,
102		phys_addr_t phys_size,
103		dma_addr_t dma_size)
104{
105	static struct lock_class_key lock_class;
106	struct drm_i915_gem_object *obj;
107	unsigned int cache_level;
108
109	GEM_BUG_ON(!phys_size || phys_size > dma_size);
110	GEM_BUG_ON(!IS_ALIGNED(phys_size, PAGE_SIZE));
111	GEM_BUG_ON(!IS_ALIGNED(dma_size, I915_GTT_PAGE_SIZE));
112
113	if (overflows_type(dma_size, obj->base.size))
114		return ERR_PTR(-E2BIG);
115
116	obj = i915_gem_object_alloc();
117	if (!obj)
118		return ERR_PTR(-ENOMEM);
119
120	drm_gem_private_object_init(&i915->drm, &obj->base, dma_size);
121	i915_gem_object_init(obj, &huge_ops, &lock_class, 0);
122	obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
123
124	obj->read_domains = I915_GEM_DOMAIN_CPU;
125	obj->write_domain = I915_GEM_DOMAIN_CPU;
126	cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
127	i915_gem_object_set_cache_coherency(obj, cache_level);
128	obj->scratch = phys_size;
129
130	return obj;
131}