Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...
[linux-2.6.git] / drivers / media / video / videobuf2-vmalloc.c
1 /*
2  * videobuf2-vmalloc.c - vmalloc memory allocator for videobuf2
3  *
4  * Copyright (C) 2010 Samsung Electronics
5  *
6  * Author: Pawel Osciak <pawel@osciak.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation.
11  */
12
13 #include <linux/module.h>
14 #include <linux/mm.h>
15 #include <linux/sched.h>
16 #include <linux/slab.h>
17 #include <linux/vmalloc.h>
18
19 #include <media/videobuf2-core.h>
20 #include <media/videobuf2-memops.h>
21
22 struct vb2_vmalloc_buf {
23         void                            *vaddr;
24         struct page                     **pages;
25         int                             write;
26         unsigned long                   size;
27         unsigned int                    n_pages;
28         atomic_t                        refcount;
29         struct vb2_vmarea_handler       handler;
30 };
31
32 static void vb2_vmalloc_put(void *buf_priv);
33
34 static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
35 {
36         struct vb2_vmalloc_buf *buf;
37
38         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
39         if (!buf)
40                 return NULL;
41
42         buf->size = size;
43         buf->vaddr = vmalloc_user(buf->size);
44         buf->handler.refcount = &buf->refcount;
45         buf->handler.put = vb2_vmalloc_put;
46         buf->handler.arg = buf;
47
48         if (!buf->vaddr) {
49                 pr_debug("vmalloc of size %ld failed\n", buf->size);
50                 kfree(buf);
51                 return NULL;
52         }
53
54         atomic_inc(&buf->refcount);
55         return buf;
56 }
57
58 static void vb2_vmalloc_put(void *buf_priv)
59 {
60         struct vb2_vmalloc_buf *buf = buf_priv;
61
62         if (atomic_dec_and_test(&buf->refcount)) {
63                 vfree(buf->vaddr);
64                 kfree(buf);
65         }
66 }
67
68 static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
69                                      unsigned long size, int write)
70 {
71         struct vb2_vmalloc_buf *buf;
72         unsigned long first, last;
73         int n_pages, offset;
74
75         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
76         if (!buf)
77                 return NULL;
78
79         buf->write = write;
80         offset = vaddr & ~PAGE_MASK;
81         buf->size = size;
82
83         first = vaddr >> PAGE_SHIFT;
84         last  = (vaddr + size - 1) >> PAGE_SHIFT;
85         buf->n_pages = last - first + 1;
86         buf->pages = kzalloc(buf->n_pages * sizeof(struct page *), GFP_KERNEL);
87         if (!buf->pages)
88                 goto fail_pages_array_alloc;
89
90         /* current->mm->mmap_sem is taken by videobuf2 core */
91         n_pages = get_user_pages(current, current->mm, vaddr & PAGE_MASK,
92                                  buf->n_pages, write, 1, /* force */
93                                  buf->pages, NULL);
94         if (n_pages != buf->n_pages)
95                 goto fail_get_user_pages;
96
97         buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1, PAGE_KERNEL);
98         if (!buf->vaddr)
99                 goto fail_get_user_pages;
100
101         buf->vaddr += offset;
102         return buf;
103
104 fail_get_user_pages:
105         pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
106                  buf->n_pages);
107         while (--n_pages >= 0)
108                 put_page(buf->pages[n_pages]);
109         kfree(buf->pages);
110
111 fail_pages_array_alloc:
112         kfree(buf);
113
114         return NULL;
115 }
116
117 static void vb2_vmalloc_put_userptr(void *buf_priv)
118 {
119         struct vb2_vmalloc_buf *buf = buf_priv;
120         unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
121         unsigned int i;
122
123         if (vaddr)
124                 vm_unmap_ram((void *)vaddr, buf->n_pages);
125         for (i = 0; i < buf->n_pages; ++i) {
126                 if (buf->write)
127                         set_page_dirty_lock(buf->pages[i]);
128                 put_page(buf->pages[i]);
129         }
130         kfree(buf->pages);
131         kfree(buf);
132 }
133
134 static void *vb2_vmalloc_vaddr(void *buf_priv)
135 {
136         struct vb2_vmalloc_buf *buf = buf_priv;
137
138         if (!buf->vaddr) {
139                 pr_err("Address of an unallocated plane requested "
140                        "or cannot map user pointer\n");
141                 return NULL;
142         }
143
144         return buf->vaddr;
145 }
146
147 static unsigned int vb2_vmalloc_num_users(void *buf_priv)
148 {
149         struct vb2_vmalloc_buf *buf = buf_priv;
150         return atomic_read(&buf->refcount);
151 }
152
153 static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
154 {
155         struct vb2_vmalloc_buf *buf = buf_priv;
156         int ret;
157
158         if (!buf) {
159                 pr_err("No memory to map\n");
160                 return -EINVAL;
161         }
162
163         ret = remap_vmalloc_range(vma, buf->vaddr, 0);
164         if (ret) {
165                 pr_err("Remapping vmalloc memory, error: %d\n", ret);
166                 return ret;
167         }
168
169         /*
170          * Make sure that vm_areas for 2 buffers won't be merged together
171          */
172         vma->vm_flags           |= VM_DONTEXPAND;
173
174         /*
175          * Use common vm_area operations to track buffer refcount.
176          */
177         vma->vm_private_data    = &buf->handler;
178         vma->vm_ops             = &vb2_common_vm_ops;
179
180         vma->vm_ops->open(vma);
181
182         return 0;
183 }
184
185 const struct vb2_mem_ops vb2_vmalloc_memops = {
186         .alloc          = vb2_vmalloc_alloc,
187         .put            = vb2_vmalloc_put,
188         .get_userptr    = vb2_vmalloc_get_userptr,
189         .put_userptr    = vb2_vmalloc_put_userptr,
190         .vaddr          = vb2_vmalloc_vaddr,
191         .mmap           = vb2_vmalloc_mmap,
192         .num_users      = vb2_vmalloc_num_users,
193 };
194 EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
195
196 MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
197 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
198 MODULE_LICENSE("GPL");