1/*	$NetBSD: huge_gem_object.c,v 1.2 2021/12/18 23:45:30 riastradh Exp $	*/
2
3/*
4 * SPDX-License-Identifier: MIT
5 *
6 * Copyright �� 2016 Intel Corporation
7 */
8
9#include <sys/cdefs.h>
10__KERNEL_RCSID(0, "$NetBSD: huge_gem_object.c,v 1.2 2021/12/18 23:45:30 riastradh Exp $");
11
12#include "i915_scatterlist.h"
13
14#include "huge_gem_object.h"
15
16static void huge_free_pages(struct drm_i915_gem_object *obj,
17			    struct sg_table *pages)
18{
19	unsigned long nreal = obj->scratch / PAGE_SIZE;
20	struct sgt_iter sgt_iter;
21	struct page *page;
22
23	for_each_sgt_page(page, sgt_iter, pages) {
24		__free_page(page);
25		if (!--nreal)
26			break;
27	}
28
29	sg_free_table(pages);
30	kfree(pages);
31}
32
33static int huge_get_pages(struct drm_i915_gem_object *obj)
34{
35#define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY)
36	const unsigned long nreal = obj->scratch / PAGE_SIZE;
37	const unsigned long npages = obj->base.size / PAGE_SIZE;
38	struct scatterlist *sg, *src, *end;
39	struct sg_table *pages;
40	unsigned long n;
41
42	pages = kmalloc(sizeof(*pages), GFP);
43	if (!pages)
44		return -ENOMEM;
45
46	if (sg_alloc_table(pages, npages, GFP)) {
47		kfree(pages);
48		return -ENOMEM;
49	}
50
51	sg = pages->sgl;
52	for (n = 0; n < nreal; n++) {
53		struct page *page;
54
55		page = alloc_page(GFP | __GFP_HIGHMEM);
56		if (!page) {
57			sg_mark_end(sg);
58			goto err;
59		}
60
61		sg_set_page(sg, page, PAGE_SIZE, 0);
62		sg = __sg_next(sg);
63	}
64	if (nreal < npages) {
65		for (end = sg, src = pages->sgl; sg; sg = __sg_next(sg)) {
66			sg_set_page(sg, sg_page(src), PAGE_SIZE, 0);
67			src = __sg_next(src);
68			if (src == end)
69				src = pages->sgl;
70		}
71	}
72
73	if (i915_gem_gtt_prepare_pages(obj, pages))
74		goto err;
75
76	__i915_gem_object_set_pages(obj, pages, PAGE_SIZE);
77
78	return 0;
79
80err:
81	huge_free_pages(obj, pages);
82	return -ENOMEM;
83#undef GFP
84}
85
86static void huge_put_pages(struct drm_i915_gem_object *obj,
87			   struct sg_table *pages)
88{
89	i915_gem_gtt_finish_pages(obj, pages);
90	huge_free_pages(obj, pages);
91
92	obj->mm.dirty = false;
93}
94
95static const struct drm_i915_gem_object_ops huge_ops = {
96	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
97		 I915_GEM_OBJECT_IS_SHRINKABLE,
98	.get_pages = huge_get_pages,
99	.put_pages = huge_put_pages,
100};
101
102struct drm_i915_gem_object *
103huge_gem_object(struct drm_i915_private *i915,
104		phys_addr_t phys_size,
105		dma_addr_t dma_size)
106{
107	static struct lock_class_key lock_class;
108	struct drm_i915_gem_object *obj;
109	unsigned int cache_level;
110
111	GEM_BUG_ON(!phys_size || phys_size > dma_size);
112	GEM_BUG_ON(!IS_ALIGNED(phys_size, PAGE_SIZE));
113	GEM_BUG_ON(!IS_ALIGNED(dma_size, I915_GTT_PAGE_SIZE));
114
115	if (overflows_type(dma_size, obj->base.size))
116		return ERR_PTR(-E2BIG);
117
118	obj = i915_gem_object_alloc();
119	if (!obj)
120		return ERR_PTR(-ENOMEM);
121
122	drm_gem_private_object_init(&i915->drm, &obj->base, dma_size);
123	i915_gem_object_init(obj, &huge_ops, &lock_class);
124
125	obj->read_domains = I915_GEM_DOMAIN_CPU;
126	obj->write_domain = I915_GEM_DOMAIN_CPU;
127	cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
128	i915_gem_object_set_cache_coherency(obj, cache_level);
129	obj->scratch = phys_size;
130
131	return obj;
132}
133