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 
11 static 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 scatterlist *sg;
16 
17 	for (sg = pages->sgl; sg && nreal--; sg = __sg_next(sg))
18 		__free_page(sg_page(sg));
19 
20 	sg_free_table(pages);
21 	kfree(pages);
22 }
23 
24 static int huge_get_pages(struct drm_i915_gem_object *obj)
25 {
26 #define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY)
27 	const unsigned long nreal = obj->scratch / PAGE_SIZE;
28 	const unsigned long npages = obj->base.size / PAGE_SIZE;
29 	struct scatterlist *sg, *src, *end;
30 	struct sg_table *pages;
31 	unsigned long n;
32 
33 	pages = kmalloc(sizeof(*pages), GFP);
34 	if (!pages)
35 		return -ENOMEM;
36 
37 	if (sg_alloc_table(pages, npages, GFP)) {
38 		kfree(pages);
39 		return -ENOMEM;
40 	}
41 
42 	sg = pages->sgl;
43 	for (n = 0; n < nreal; n++) {
44 		struct page *page;
45 
46 		page = alloc_page(GFP | __GFP_HIGHMEM);
47 		if (!page) {
48 			sg_mark_end(sg);
49 			goto err;
50 		}
51 
52 		sg_set_page(sg, page, PAGE_SIZE, 0);
53 		sg = __sg_next(sg);
54 	}
55 	if (nreal < npages) {
56 		for (end = sg, src = pages->sgl; sg; sg = __sg_next(sg)) {
57 			sg_set_page(sg, sg_page(src), PAGE_SIZE, 0);
58 			src = __sg_next(src);
59 			if (src == end)
60 				src = pages->sgl;
61 		}
62 	}
63 
64 	if (i915_gem_gtt_prepare_pages(obj, pages))
65 		goto err;
66 
67 	__i915_gem_object_set_pages(obj, pages, PAGE_SIZE);
68 
69 	return 0;
70 
71 err:
72 	huge_free_pages(obj, pages);
73 
74 	return -ENOMEM;
75 #undef GFP
76 }
77 
78 static void huge_put_pages(struct drm_i915_gem_object *obj,
79 			   struct sg_table *pages)
80 {
81 	i915_gem_gtt_finish_pages(obj, pages);
82 	huge_free_pages(obj, pages);
83 
84 	obj->mm.dirty = false;
85 }
86 
87 static const struct drm_i915_gem_object_ops huge_ops = {
88 	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
89 		 I915_GEM_OBJECT_IS_SHRINKABLE,
90 	.get_pages = huge_get_pages,
91 	.put_pages = huge_put_pages,
92 };
93 
94 struct drm_i915_gem_object *
95 huge_gem_object(struct drm_i915_private *i915,
96 		phys_addr_t phys_size,
97 		dma_addr_t dma_size)
98 {
99 	static struct lock_class_key lock_class;
100 	struct drm_i915_gem_object *obj;
101 	unsigned int cache_level;
102 
103 	GEM_BUG_ON(!phys_size || phys_size > dma_size);
104 	GEM_BUG_ON(!IS_ALIGNED(phys_size, PAGE_SIZE));
105 	GEM_BUG_ON(!IS_ALIGNED(dma_size, I915_GTT_PAGE_SIZE));
106 
107 	if (overflows_type(dma_size, obj->base.size))
108 		return ERR_PTR(-E2BIG);
109 
110 	obj = i915_gem_object_alloc();
111 	if (!obj)
112 		return ERR_PTR(-ENOMEM);
113 
114 	drm_gem_private_object_init(&i915->drm, &obj->base, dma_size);
115 	i915_gem_object_init(obj, &huge_ops, &lock_class);
116 
117 	obj->read_domains = I915_GEM_DOMAIN_CPU;
118 	obj->write_domain = I915_GEM_DOMAIN_CPU;
119 	cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
120 	i915_gem_object_set_cache_coherency(obj, cache_level);
121 	obj->scratch = phys_size;
122 
123 	return obj;
124 }
125