1/*	$NetBSD: mock_dmabuf.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: mock_dmabuf.c,v 1.2 2021/12/18 23:45:30 riastradh Exp $");
11
12#include "mock_dmabuf.h"
13
14static struct sg_table *mock_map_dma_buf(struct dma_buf_attachment *attachment,
15					 enum dma_data_direction dir)
16{
17	struct mock_dmabuf *mock = to_mock(attachment->dmabuf);
18	struct sg_table *st;
19	struct scatterlist *sg;
20	int i, err;
21
22	st = kmalloc(sizeof(*st), GFP_KERNEL);
23	if (!st)
24		return ERR_PTR(-ENOMEM);
25
26	err = sg_alloc_table(st, mock->npages, GFP_KERNEL);
27	if (err)
28		goto err_free;
29
30	sg = st->sgl;
31	for (i = 0; i < mock->npages; i++) {
32		sg_set_page(sg, mock->pages[i], PAGE_SIZE, 0);
33		sg = sg_next(sg);
34	}
35
36	if (!dma_map_sg(attachment->dev, st->sgl, st->nents, dir)) {
37		err = -ENOMEM;
38		goto err_st;
39	}
40
41	return st;
42
43err_st:
44	sg_free_table(st);
45err_free:
46	kfree(st);
47	return ERR_PTR(err);
48}
49
50static void mock_unmap_dma_buf(struct dma_buf_attachment *attachment,
51			       struct sg_table *st,
52			       enum dma_data_direction dir)
53{
54	dma_unmap_sg(attachment->dev, st->sgl, st->nents, dir);
55	sg_free_table(st);
56	kfree(st);
57}
58
59static void mock_dmabuf_release(struct dma_buf *dma_buf)
60{
61	struct mock_dmabuf *mock = to_mock(dma_buf);
62	int i;
63
64	for (i = 0; i < mock->npages; i++)
65		put_page(mock->pages[i]);
66
67	kfree(mock);
68}
69
70static void *mock_dmabuf_vmap(struct dma_buf *dma_buf)
71{
72	struct mock_dmabuf *mock = to_mock(dma_buf);
73
74	return vm_map_ram(mock->pages, mock->npages, 0, PAGE_KERNEL);
75}
76
77static void mock_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
78{
79	struct mock_dmabuf *mock = to_mock(dma_buf);
80
81	vm_unmap_ram(vaddr, mock->npages);
82}
83
84static int mock_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
85{
86	return -ENODEV;
87}
88
89static 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
98static 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
128err:
129	while (i--)
130		put_page(mock->pages[i]);
131	kfree(mock);
132	return ERR_PTR(-ENOMEM);
133}
134