1 /*
2  * SPDX-License-Identifier: MIT
3  *
4  * Copyright © 2016 Intel Corporation
5  */
6 
7 #include "mock_dmabuf.h"
8 
9 static struct sg_table *mock_map_dma_buf(struct dma_buf_attachment *attachment,
10 					 enum dma_data_direction dir)
11 {
12 	struct mock_dmabuf *mock = to_mock(attachment->dmabuf);
13 	struct sg_table *st;
14 	struct scatterlist *sg;
15 	int i, err;
16 
17 	st = kmalloc(sizeof(*st), GFP_KERNEL);
18 	if (!st)
19 		return ERR_PTR(-ENOMEM);
20 
21 	err = sg_alloc_table(st, mock->npages, GFP_KERNEL);
22 	if (err)
23 		goto err_free;
24 
25 	sg = st->sgl;
26 	for (i = 0; i < mock->npages; i++) {
27 		sg_set_page(sg, mock->pages[i], PAGE_SIZE, 0);
28 		sg = sg_next(sg);
29 	}
30 
31 	err = dma_map_sgtable(attachment->dev, st, dir, 0);
32 	if (err)
33 		goto err_st;
34 
35 	return st;
36 
37 err_st:
38 	sg_free_table(st);
39 err_free:
40 	kfree(st);
41 	return ERR_PTR(err);
42 }
43 
44 static void mock_unmap_dma_buf(struct dma_buf_attachment *attachment,
45 			       struct sg_table *st,
46 			       enum dma_data_direction dir)
47 {
48 	dma_unmap_sgtable(attachment->dev, st, dir, 0);
49 	sg_free_table(st);
50 	kfree(st);
51 }
52 
53 static void mock_dmabuf_release(struct dma_buf *dma_buf)
54 {
55 	struct mock_dmabuf *mock = to_mock(dma_buf);
56 	int i;
57 
58 	for (i = 0; i < mock->npages; i++)
59 		put_page(mock->pages[i]);
60 
61 	kfree(mock);
62 }
63 
64 static int mock_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map)
65 {
66 	struct mock_dmabuf *mock = to_mock(dma_buf);
67 	void *vaddr;
68 
69 	vaddr = vm_map_ram(mock->pages, mock->npages, 0);
70 	if (!vaddr)
71 		return -ENOMEM;
72 	dma_buf_map_set_vaddr(map, vaddr);
73 
74 	return 0;
75 }
76 
77 static void mock_dmabuf_vunmap(struct dma_buf *dma_buf, struct dma_buf_map *map)
78 {
79 	struct mock_dmabuf *mock = to_mock(dma_buf);
80 
81 	vm_unmap_ram(map->vaddr, mock->npages);
82 }
83 
84 static int mock_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
85 {
86 	return -ENODEV;
87 }
88 
89 static const struct dma_buf_ops mock_dmabuf_ops =  {
90 	.map_dma_buf = mock_map_dma_buf,
91 	.unmap_dma_buf = mock_unmap_dma_buf,
92 	.release = mock_dmabuf_release,
93 	.mmap = mock_dmabuf_mmap,
94 	.vmap = mock_dmabuf_vmap,
95 	.vunmap = mock_dmabuf_vunmap,
96 };
97 
98 static struct dma_buf *mock_dmabuf(int npages)
99 {
100 	struct mock_dmabuf *mock;
101 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
102 	struct dma_buf *dmabuf;
103 	int i;
104 
105 	mock = kmalloc(sizeof(*mock) + npages * sizeof(struct page *),
106 		       GFP_KERNEL);
107 	if (!mock)
108 		return ERR_PTR(-ENOMEM);
109 
110 	mock->npages = npages;
111 	for (i = 0; i < npages; i++) {
112 		mock->pages[i] = alloc_page(GFP_KERNEL);
113 		if (!mock->pages[i])
114 			goto err;
115 	}
116 
117 	exp_info.ops = &mock_dmabuf_ops;
118 	exp_info.size = npages * PAGE_SIZE;
119 	exp_info.flags = O_CLOEXEC;
120 	exp_info.priv = mock;
121 
122 	dmabuf = dma_buf_export(&exp_info);
123 	if (IS_ERR(dmabuf))
124 		goto err;
125 
126 	return dmabuf;
127 
128 err:
129 	while (i--)
130 		put_page(mock->pages[i]);
131 	kfree(mock);
132 	return ERR_PTR(-ENOMEM);
133 }
134