1 | /* |
2 | * videobuf2-memops.c - generic memory handling routines for videobuf2 |
3 | * |
4 | * Copyright (C) 2010 Samsung Electronics |
5 | * |
6 | * Author: Pawel Osciak <pawel@osciak.com> |
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> |
21 | |
22 | #include <media/videobuf2-v4l2.h> |
23 | #include <media/videobuf2-memops.h> |
24 | |
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_frames: nr); |
50 | if (!vec) |
51 | return ERR_PTR(error: -ENOMEM); |
52 | ret = get_vaddr_frames(start: start & PAGE_MASK, nr_pfns: nr, write, vec); |
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(error: 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 | |
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 | |
94 | pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n" , |
95 | __func__, h, refcount_read(h->refcount), vma->vm_start, |
96 | vma->vm_end); |
97 | |
98 | refcount_inc(r: 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 | |
112 | pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n" , |
113 | __func__, h, refcount_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 mmapped |
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" ); |
130 | MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>" ); |
131 | MODULE_LICENSE("GPL" ); |
132 | |