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004cc378 MS |
1 | /* |
2 | * videobuf2-memops.c - generic memory handling routines for videobuf2 | |
3 | * | |
4 | * Copyright (C) 2010 Samsung Electronics | |
5 | * | |
95072084 | 6 | * Author: Pawel Osciak <pawel@osciak.com> |
004cc378 MS |
7 | * Marek Szyprowski <m.szyprowski@samsung.com> |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/slab.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/dma-mapping.h> | |
17 | #include <linux/vmalloc.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/sched.h> | |
20 | #include <linux/file.h> | |
004cc378 | 21 | |
c139990e | 22 | #include <media/videobuf2-v4l2.h> |
004cc378 MS |
23 | #include <media/videobuf2-memops.h> |
24 | ||
21fb0cb7 JK |
25 | /** |
26 | * vb2_create_framevec() - map virtual addresses to pfns | |
27 | * @start: Virtual user address where we start mapping | |
28 | * @length: Length of a range to map | |
29 | * @write: Should we map for writing into the area | |
30 | * | |
31 | * This function allocates and fills in a vector with pfns corresponding to | |
32 | * virtual address range passed in arguments. If pfns have corresponding pages, | |
33 | * page references are also grabbed to pin pages in memory. The function | |
34 | * returns pointer to the vector on success and error pointer in case of | |
35 | * failure. Returned vector needs to be freed via vb2_destroy_pfnvec(). | |
36 | */ | |
37 | struct frame_vector *vb2_create_framevec(unsigned long start, | |
38 | unsigned long length, | |
39 | bool write) | |
40 | { | |
41 | int ret; | |
42 | unsigned long first, last; | |
43 | unsigned long nr; | |
44 | struct frame_vector *vec; | |
45 | ||
46 | first = start >> PAGE_SHIFT; | |
47 | last = (start + length - 1) >> PAGE_SHIFT; | |
48 | nr = last - first + 1; | |
49 | vec = frame_vector_create(nr); | |
50 | if (!vec) | |
51 | return ERR_PTR(-ENOMEM); | |
89a09566 | 52 | ret = get_vaddr_frames(start & PAGE_MASK, nr, write, true, vec); |
21fb0cb7 JK |
53 | if (ret < 0) |
54 | goto out_destroy; | |
55 | /* We accept only complete set of PFNs */ | |
56 | if (ret != nr) { | |
57 | ret = -EFAULT; | |
58 | goto out_release; | |
59 | } | |
60 | return vec; | |
61 | out_release: | |
62 | put_vaddr_frames(vec); | |
63 | out_destroy: | |
64 | frame_vector_destroy(vec); | |
65 | return ERR_PTR(ret); | |
66 | } | |
67 | EXPORT_SYMBOL(vb2_create_framevec); | |
68 | ||
69 | /** | |
70 | * vb2_destroy_framevec() - release vector of mapped pfns | |
71 | * @vec: vector of pfns / pages to release | |
72 | * | |
73 | * This releases references to all pages in the vector @vec (if corresponding | |
74 | * pfns are backed by pages) and frees the passed vector. | |
75 | */ | |
76 | void vb2_destroy_framevec(struct frame_vector *vec) | |
77 | { | |
78 | put_vaddr_frames(vec); | |
79 | frame_vector_destroy(vec); | |
80 | } | |
81 | EXPORT_SYMBOL(vb2_destroy_framevec); | |
82 | ||
004cc378 MS |
83 | /** |
84 | * vb2_common_vm_open() - increase refcount of the vma | |
85 | * @vma: virtual memory region for the mapping | |
86 | * | |
87 | * This function adds another user to the provided vma. It expects | |
88 | * struct vb2_vmarea_handler pointer in vma->vm_private_data. | |
89 | */ | |
90 | static void vb2_common_vm_open(struct vm_area_struct *vma) | |
91 | { | |
92 | struct vb2_vmarea_handler *h = vma->vm_private_data; | |
93 | ||
7f116b3e | 94 | pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n", |
004cc378 MS |
95 | __func__, h, atomic_read(h->refcount), vma->vm_start, |
96 | vma->vm_end); | |
97 | ||
98 | atomic_inc(h->refcount); | |
99 | } | |
100 | ||
101 | /** | |
102 | * vb2_common_vm_close() - decrease refcount of the vma | |
103 | * @vma: virtual memory region for the mapping | |
104 | * | |
105 | * This function releases the user from the provided vma. It expects | |
106 | * struct vb2_vmarea_handler pointer in vma->vm_private_data. | |
107 | */ | |
108 | static void vb2_common_vm_close(struct vm_area_struct *vma) | |
109 | { | |
110 | struct vb2_vmarea_handler *h = vma->vm_private_data; | |
111 | ||
7f116b3e | 112 | pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n", |
004cc378 MS |
113 | __func__, h, atomic_read(h->refcount), vma->vm_start, |
114 | vma->vm_end); | |
115 | ||
116 | h->put(h->arg); | |
117 | } | |
118 | ||
119 | /** | |
120 | * vb2_common_vm_ops - common vm_ops used for tracking refcount of mmaped | |
121 | * video buffers | |
122 | */ | |
123 | const struct vm_operations_struct vb2_common_vm_ops = { | |
124 | .open = vb2_common_vm_open, | |
125 | .close = vb2_common_vm_close, | |
126 | }; | |
127 | EXPORT_SYMBOL_GPL(vb2_common_vm_ops); | |
128 | ||
129 | MODULE_DESCRIPTION("common memory handling routines for videobuf2"); | |
95072084 | 130 | MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>"); |
004cc378 | 131 | MODULE_LICENSE("GPL"); |