diff options
author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
---|---|---|
committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /drivers/media/video/videobuf2-dma-sg.c | |
parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) |
Diffstat (limited to 'drivers/media/video/videobuf2-dma-sg.c')
-rw-r--r-- | drivers/media/video/videobuf2-dma-sg.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/media/video/videobuf2-dma-sg.c b/drivers/media/video/videobuf2-dma-sg.c new file mode 100644 index 00000000000..065f468faf8 --- /dev/null +++ b/drivers/media/video/videobuf2-dma-sg.c | |||
@@ -0,0 +1,290 @@ | |||
1 | /* | ||
2 | * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2 | ||
3 | * | ||
4 | * Copyright (C) 2010 Samsung Electronics | ||
5 | * | ||
6 | * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.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/scatterlist.h> | ||
16 | #include <linux/sched.h> | ||
17 | #include <linux/slab.h> | ||
18 | #include <linux/vmalloc.h> | ||
19 | |||
20 | #include <media/videobuf2-core.h> | ||
21 | #include <media/videobuf2-memops.h> | ||
22 | #include <media/videobuf2-dma-sg.h> | ||
23 | |||
24 | struct vb2_dma_sg_buf { | ||
25 | void *vaddr; | ||
26 | struct page **pages; | ||
27 | int write; | ||
28 | int offset; | ||
29 | struct vb2_dma_sg_desc sg_desc; | ||
30 | atomic_t refcount; | ||
31 | struct vb2_vmarea_handler handler; | ||
32 | }; | ||
33 | |||
34 | static void vb2_dma_sg_put(void *buf_priv); | ||
35 | |||
36 | static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size) | ||
37 | { | ||
38 | struct vb2_dma_sg_buf *buf; | ||
39 | int i; | ||
40 | |||
41 | buf = kzalloc(sizeof *buf, GFP_KERNEL); | ||
42 | if (!buf) | ||
43 | return NULL; | ||
44 | |||
45 | buf->vaddr = NULL; | ||
46 | buf->write = 0; | ||
47 | buf->offset = 0; | ||
48 | buf->sg_desc.size = size; | ||
49 | buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | ||
50 | |||
51 | buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages * | ||
52 | sizeof(*buf->sg_desc.sglist)); | ||
53 | if (!buf->sg_desc.sglist) | ||
54 | goto fail_sglist_alloc; | ||
55 | sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); | ||
56 | |||
57 | buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), | ||
58 | GFP_KERNEL); | ||
59 | if (!buf->pages) | ||
60 | goto fail_pages_array_alloc; | ||
61 | |||
62 | for (i = 0; i < buf->sg_desc.num_pages; ++i) { | ||
63 | buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); | ||
64 | if (NULL == buf->pages[i]) | ||
65 | goto fail_pages_alloc; | ||
66 | sg_set_page(&buf->sg_desc.sglist[i], | ||
67 | buf->pages[i], PAGE_SIZE, 0); | ||
68 | } | ||
69 | |||
70 | buf->handler.refcount = &buf->refcount; | ||
71 | buf->handler.put = vb2_dma_sg_put; | ||
72 | buf->handler.arg = buf; | ||
73 | |||
74 | atomic_inc(&buf->refcount); | ||
75 | |||
76 | printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n", | ||
77 | __func__, buf->sg_desc.num_pages); | ||
78 | |||
79 | if (!buf->vaddr) | ||
80 | buf->vaddr = vm_map_ram(buf->pages, | ||
81 | buf->sg_desc.num_pages, | ||
82 | -1, | ||
83 | PAGE_KERNEL); | ||
84 | return buf; | ||
85 | |||
86 | fail_pages_alloc: | ||
87 | while (--i >= 0) | ||
88 | __free_page(buf->pages[i]); | ||
89 | kfree(buf->pages); | ||
90 | |||
91 | fail_pages_array_alloc: | ||
92 | vfree(buf->sg_desc.sglist); | ||
93 | |||
94 | fail_sglist_alloc: | ||
95 | kfree(buf); | ||
96 | return NULL; | ||
97 | } | ||
98 | |||
99 | static void vb2_dma_sg_put(void *buf_priv) | ||
100 | { | ||
101 | struct vb2_dma_sg_buf *buf = buf_priv; | ||
102 | int i = buf->sg_desc.num_pages; | ||
103 | |||
104 | if (atomic_dec_and_test(&buf->refcount)) { | ||
105 | printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__, | ||
106 | buf->sg_desc.num_pages); | ||
107 | if (buf->vaddr) | ||
108 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); | ||
109 | vfree(buf->sg_desc.sglist); | ||
110 | while (--i >= 0) | ||
111 | __free_page(buf->pages[i]); | ||
112 | kfree(buf->pages); | ||
113 | kfree(buf); | ||
114 | } | ||
115 | } | ||
116 | |||
117 | static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, | ||
118 | unsigned long size, int write) | ||
119 | { | ||
120 | struct vb2_dma_sg_buf *buf; | ||
121 | unsigned long first, last; | ||
122 | int num_pages_from_user, i; | ||
123 | |||
124 | buf = kzalloc(sizeof *buf, GFP_KERNEL); | ||
125 | if (!buf) | ||
126 | return NULL; | ||
127 | |||
128 | buf->vaddr = NULL; | ||
129 | buf->write = write; | ||
130 | buf->offset = vaddr & ~PAGE_MASK; | ||
131 | buf->sg_desc.size = size; | ||
132 | |||
133 | first = (vaddr & PAGE_MASK) >> PAGE_SHIFT; | ||
134 | last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT; | ||
135 | buf->sg_desc.num_pages = last - first + 1; | ||
136 | |||
137 | buf->sg_desc.sglist = vzalloc( | ||
138 | buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist)); | ||
139 | if (!buf->sg_desc.sglist) | ||
140 | goto userptr_fail_sglist_alloc; | ||
141 | |||
142 | sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); | ||
143 | |||
144 | buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), | ||
145 | GFP_KERNEL); | ||
146 | if (!buf->pages) | ||
147 | goto userptr_fail_pages_array_alloc; | ||
148 | |||
149 | down_read(¤t->mm->mmap_sem); | ||
150 | num_pages_from_user = get_user_pages(current, current->mm, | ||
151 | vaddr & PAGE_MASK, | ||
152 | buf->sg_desc.num_pages, | ||
153 | write, | ||
154 | 1, /* force */ | ||
155 | buf->pages, | ||
156 | NULL); | ||
157 | up_read(¤t->mm->mmap_sem); | ||
158 | if (num_pages_from_user != buf->sg_desc.num_pages) | ||
159 | goto userptr_fail_get_user_pages; | ||
160 | |||
161 | sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0], | ||
162 | PAGE_SIZE - buf->offset, buf->offset); | ||
163 | size -= PAGE_SIZE - buf->offset; | ||
164 | for (i = 1; i < buf->sg_desc.num_pages; ++i) { | ||
165 | sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i], | ||
166 | min_t(size_t, PAGE_SIZE, size), 0); | ||
167 | size -= min_t(size_t, PAGE_SIZE, size); | ||
168 | } | ||
169 | return buf; | ||
170 | |||
171 | userptr_fail_get_user_pages: | ||
172 | printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n", | ||
173 | num_pages_from_user, buf->sg_desc.num_pages); | ||
174 | while (--num_pages_from_user >= 0) | ||
175 | put_page(buf->pages[num_pages_from_user]); | ||
176 | kfree(buf->pages); | ||
177 | |||
178 | userptr_fail_pages_array_alloc: | ||
179 | vfree(buf->sg_desc.sglist); | ||
180 | |||
181 | userptr_fail_sglist_alloc: | ||
182 | kfree(buf); | ||
183 | return NULL; | ||
184 | } | ||
185 | |||
186 | /* | ||
187 | * @put_userptr: inform the allocator that a USERPTR buffer will no longer | ||
188 | * be used | ||
189 | */ | ||
190 | static void vb2_dma_sg_put_userptr(void *buf_priv) | ||
191 | { | ||
192 | struct vb2_dma_sg_buf *buf = buf_priv; | ||
193 | int i = buf->sg_desc.num_pages; | ||
194 | |||
195 | printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n", | ||
196 | __func__, buf->sg_desc.num_pages); | ||
197 | if (buf->vaddr) | ||
198 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); | ||
199 | while (--i >= 0) { | ||
200 | if (buf->write) | ||
201 | set_page_dirty_lock(buf->pages[i]); | ||
202 | put_page(buf->pages[i]); | ||
203 | } | ||
204 | vfree(buf->sg_desc.sglist); | ||
205 | kfree(buf->pages); | ||
206 | kfree(buf); | ||
207 | } | ||
208 | |||
209 | static void *vb2_dma_sg_vaddr(void *buf_priv) | ||
210 | { | ||
211 | struct vb2_dma_sg_buf *buf = buf_priv; | ||
212 | |||
213 | BUG_ON(!buf); | ||
214 | |||
215 | if (!buf->vaddr) | ||
216 | buf->vaddr = vm_map_ram(buf->pages, | ||
217 | buf->sg_desc.num_pages, | ||
218 | -1, | ||
219 | PAGE_KERNEL); | ||
220 | |||
221 | /* add offset in case userptr is not page-aligned */ | ||
222 | return buf->vaddr + buf->offset; | ||
223 | } | ||
224 | |||
225 | static unsigned int vb2_dma_sg_num_users(void *buf_priv) | ||
226 | { | ||
227 | struct vb2_dma_sg_buf *buf = buf_priv; | ||
228 | |||
229 | return atomic_read(&buf->refcount); | ||
230 | } | ||
231 | |||
232 | static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) | ||
233 | { | ||
234 | struct vb2_dma_sg_buf *buf = buf_priv; | ||
235 | unsigned long uaddr = vma->vm_start; | ||
236 | unsigned long usize = vma->vm_end - vma->vm_start; | ||
237 | int i = 0; | ||
238 | |||
239 | if (!buf) { | ||
240 | printk(KERN_ERR "No memory to map\n"); | ||
241 | return -EINVAL; | ||
242 | } | ||
243 | |||
244 | do { | ||
245 | int ret; | ||
246 | |||
247 | ret = vm_insert_page(vma, uaddr, buf->pages[i++]); | ||
248 | if (ret) { | ||
249 | printk(KERN_ERR "Remapping memory, error: %d\n", ret); | ||
250 | return ret; | ||
251 | } | ||
252 | |||
253 | uaddr += PAGE_SIZE; | ||
254 | usize -= PAGE_SIZE; | ||
255 | } while (usize > 0); | ||
256 | |||
257 | |||
258 | /* | ||
259 | * Use common vm_area operations to track buffer refcount. | ||
260 | */ | ||
261 | vma->vm_private_data = &buf->handler; | ||
262 | vma->vm_ops = &vb2_common_vm_ops; | ||
263 | |||
264 | vma->vm_ops->open(vma); | ||
265 | |||
266 | return 0; | ||
267 | } | ||
268 | |||
269 | static void *vb2_dma_sg_cookie(void *buf_priv) | ||
270 | { | ||
271 | struct vb2_dma_sg_buf *buf = buf_priv; | ||
272 | |||
273 | return &buf->sg_desc; | ||
274 | } | ||
275 | |||
276 | const struct vb2_mem_ops vb2_dma_sg_memops = { | ||
277 | .alloc = vb2_dma_sg_alloc, | ||
278 | .put = vb2_dma_sg_put, | ||
279 | .get_userptr = vb2_dma_sg_get_userptr, | ||
280 | .put_userptr = vb2_dma_sg_put_userptr, | ||
281 | .vaddr = vb2_dma_sg_vaddr, | ||
282 | .mmap = vb2_dma_sg_mmap, | ||
283 | .num_users = vb2_dma_sg_num_users, | ||
284 | .cookie = vb2_dma_sg_cookie, | ||
285 | }; | ||
286 | EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); | ||
287 | |||
288 | MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); | ||
289 | MODULE_AUTHOR("Andrzej Pietrasiewicz"); | ||
290 | MODULE_LICENSE("GPL"); | ||