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 void *mock_dmabuf_vmap(struct dma_buf *dma_buf)
65 {
66 	struct mock_dmabuf *mock = to_mock(dma_buf);
67 
68 	return vm_map_ram(mock->pages, mock->npages, 0);
69 }
70 
71 static void mock_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
72 {
73 	struct mock_dmabuf *mock = to_mock(dma_buf);
74 
75 	vm_unmap_ram(vaddr, mock->npages);
76 }
77 
78 static int mock_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
79 {
80 	return -ENODEV;
81 }
82 
83 static const struct dma_buf_ops mock_dmabuf_ops =  {
84 	.map_dma_buf = mock_map_dma_buf,
85 	.unmap_dma_buf = mock_unmap_dma_buf,
86 	.release = mock_dmabuf_release,
87 	.mmap = mock_dmabuf_mmap,
88 	.vmap = mock_dmabuf_vmap,
89 	.vunmap = mock_dmabuf_vunmap,
90 };
91 
92 static struct dma_buf *mock_dmabuf(int npages)
93 {
94 	struct mock_dmabuf *mock;
95 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
96 	struct dma_buf *dmabuf;
97 	int i;
98 
99 	mock = kmalloc(sizeof(*mock) + npages * sizeof(struct page *),
100 		       GFP_KERNEL);
101 	if (!mock)
102 		return ERR_PTR(-ENOMEM);
103 
104 	mock->npages = npages;
105 	for (i = 0; i < npages; i++) {
106 		mock->pages[i] = alloc_page(GFP_KERNEL);
107 		if (!mock->pages[i])
108 			goto err;
109 	}
110 
111 	exp_info.ops = &mock_dmabuf_ops;
112 	exp_info.size = npages * PAGE_SIZE;
113 	exp_info.flags = O_CLOEXEC;
114 	exp_info.priv = mock;
115 
116 	dmabuf = dma_buf_export(&exp_info);
117 	if (IS_ERR(dmabuf))
118 		goto err;
119 
120 	return dmabuf;
121 
122 err:
123 	while (i--)
124 		put_page(mock->pages[i]);
125 	kfree(mock);
126 	return ERR_PTR(-ENOMEM);
127 }
128