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5ba3f757 AP |
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 | ||
fabc6b85 | 51 | buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages * |
5ba3f757 AP |
52 | sizeof(*buf->sg_desc.sglist)); |
53 | if (!buf->sg_desc.sglist) | |
54 | goto fail_sglist_alloc; | |
5ba3f757 AP |
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) { | |
a52a82fc | 63 | buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); |
5ba3f757 AP |
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); | |
5ba3f757 AP |
78 | return buf; |
79 | ||
80 | fail_pages_alloc: | |
81 | while (--i >= 0) | |
82 | __free_page(buf->pages[i]); | |
a9bb36aa | 83 | kfree(buf->pages); |
5ba3f757 AP |
84 | |
85 | fail_pages_array_alloc: | |
86 | vfree(buf->sg_desc.sglist); | |
87 | ||
88 | fail_sglist_alloc: | |
89 | kfree(buf); | |
90 | return NULL; | |
91 | } | |
92 | ||
93 | static void vb2_dma_sg_put(void *buf_priv) | |
94 | { | |
95 | struct vb2_dma_sg_buf *buf = buf_priv; | |
96 | int i = buf->sg_desc.num_pages; | |
97 | ||
98 | if (atomic_dec_and_test(&buf->refcount)) { | |
99 | printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__, | |
100 | buf->sg_desc.num_pages); | |
101 | if (buf->vaddr) | |
102 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); | |
103 | vfree(buf->sg_desc.sglist); | |
104 | while (--i >= 0) | |
105 | __free_page(buf->pages[i]); | |
106 | kfree(buf->pages); | |
107 | kfree(buf); | |
108 | } | |
109 | } | |
110 | ||
111 | static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, | |
112 | unsigned long size, int write) | |
113 | { | |
114 | struct vb2_dma_sg_buf *buf; | |
115 | unsigned long first, last; | |
116 | int num_pages_from_user, i; | |
117 | ||
118 | buf = kzalloc(sizeof *buf, GFP_KERNEL); | |
119 | if (!buf) | |
120 | return NULL; | |
121 | ||
122 | buf->vaddr = NULL; | |
123 | buf->write = write; | |
124 | buf->offset = vaddr & ~PAGE_MASK; | |
125 | buf->sg_desc.size = size; | |
126 | ||
127 | first = (vaddr & PAGE_MASK) >> PAGE_SHIFT; | |
128 | last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT; | |
129 | buf->sg_desc.num_pages = last - first + 1; | |
130 | ||
fabc6b85 | 131 | buf->sg_desc.sglist = vzalloc( |
5ba3f757 AP |
132 | buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist)); |
133 | if (!buf->sg_desc.sglist) | |
134 | goto userptr_fail_sglist_alloc; | |
135 | ||
5ba3f757 AP |
136 | sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); |
137 | ||
138 | buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), | |
139 | GFP_KERNEL); | |
140 | if (!buf->pages) | |
141 | goto userptr_fail_pages_array_alloc; | |
142 | ||
143 | down_read(¤t->mm->mmap_sem); | |
144 | num_pages_from_user = get_user_pages(current, current->mm, | |
145 | vaddr & PAGE_MASK, | |
146 | buf->sg_desc.num_pages, | |
147 | write, | |
148 | 1, /* force */ | |
149 | buf->pages, | |
150 | NULL); | |
151 | up_read(¤t->mm->mmap_sem); | |
152 | if (num_pages_from_user != buf->sg_desc.num_pages) | |
153 | goto userptr_fail_get_user_pages; | |
154 | ||
155 | sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0], | |
156 | PAGE_SIZE - buf->offset, buf->offset); | |
157 | size -= PAGE_SIZE - buf->offset; | |
158 | for (i = 1; i < buf->sg_desc.num_pages; ++i) { | |
159 | sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i], | |
160 | min_t(size_t, PAGE_SIZE, size), 0); | |
161 | size -= min_t(size_t, PAGE_SIZE, size); | |
162 | } | |
163 | return buf; | |
164 | ||
165 | userptr_fail_get_user_pages: | |
166 | printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n", | |
167 | num_pages_from_user, buf->sg_desc.num_pages); | |
168 | while (--num_pages_from_user >= 0) | |
169 | put_page(buf->pages[num_pages_from_user]); | |
a9bb36aa | 170 | kfree(buf->pages); |
5ba3f757 AP |
171 | |
172 | userptr_fail_pages_array_alloc: | |
173 | vfree(buf->sg_desc.sglist); | |
174 | ||
175 | userptr_fail_sglist_alloc: | |
176 | kfree(buf); | |
177 | return NULL; | |
178 | } | |
179 | ||
180 | /* | |
181 | * @put_userptr: inform the allocator that a USERPTR buffer will no longer | |
182 | * be used | |
183 | */ | |
184 | static void vb2_dma_sg_put_userptr(void *buf_priv) | |
185 | { | |
186 | struct vb2_dma_sg_buf *buf = buf_priv; | |
187 | int i = buf->sg_desc.num_pages; | |
188 | ||
189 | printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n", | |
190 | __func__, buf->sg_desc.num_pages); | |
191 | if (buf->vaddr) | |
192 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); | |
193 | while (--i >= 0) { | |
194 | if (buf->write) | |
195 | set_page_dirty_lock(buf->pages[i]); | |
196 | put_page(buf->pages[i]); | |
197 | } | |
198 | vfree(buf->sg_desc.sglist); | |
199 | kfree(buf->pages); | |
200 | kfree(buf); | |
201 | } | |
202 | ||
203 | static void *vb2_dma_sg_vaddr(void *buf_priv) | |
204 | { | |
205 | struct vb2_dma_sg_buf *buf = buf_priv; | |
206 | ||
207 | BUG_ON(!buf); | |
208 | ||
209 | if (!buf->vaddr) | |
210 | buf->vaddr = vm_map_ram(buf->pages, | |
211 | buf->sg_desc.num_pages, | |
212 | -1, | |
213 | PAGE_KERNEL); | |
214 | ||
215 | /* add offset in case userptr is not page-aligned */ | |
216 | return buf->vaddr + buf->offset; | |
217 | } | |
218 | ||
219 | static unsigned int vb2_dma_sg_num_users(void *buf_priv) | |
220 | { | |
221 | struct vb2_dma_sg_buf *buf = buf_priv; | |
222 | ||
223 | return atomic_read(&buf->refcount); | |
224 | } | |
225 | ||
226 | static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) | |
227 | { | |
228 | struct vb2_dma_sg_buf *buf = buf_priv; | |
229 | unsigned long uaddr = vma->vm_start; | |
230 | unsigned long usize = vma->vm_end - vma->vm_start; | |
231 | int i = 0; | |
232 | ||
233 | if (!buf) { | |
234 | printk(KERN_ERR "No memory to map\n"); | |
235 | return -EINVAL; | |
236 | } | |
237 | ||
238 | do { | |
239 | int ret; | |
240 | ||
241 | ret = vm_insert_page(vma, uaddr, buf->pages[i++]); | |
242 | if (ret) { | |
243 | printk(KERN_ERR "Remapping memory, error: %d\n", ret); | |
244 | return ret; | |
245 | } | |
246 | ||
247 | uaddr += PAGE_SIZE; | |
248 | usize -= PAGE_SIZE; | |
249 | } while (usize > 0); | |
250 | ||
251 | ||
252 | /* | |
253 | * Use common vm_area operations to track buffer refcount. | |
254 | */ | |
255 | vma->vm_private_data = &buf->handler; | |
256 | vma->vm_ops = &vb2_common_vm_ops; | |
257 | ||
258 | vma->vm_ops->open(vma); | |
259 | ||
260 | return 0; | |
261 | } | |
262 | ||
263 | static void *vb2_dma_sg_cookie(void *buf_priv) | |
264 | { | |
265 | struct vb2_dma_sg_buf *buf = buf_priv; | |
266 | ||
267 | return &buf->sg_desc; | |
268 | } | |
269 | ||
270 | const struct vb2_mem_ops vb2_dma_sg_memops = { | |
271 | .alloc = vb2_dma_sg_alloc, | |
272 | .put = vb2_dma_sg_put, | |
273 | .get_userptr = vb2_dma_sg_get_userptr, | |
274 | .put_userptr = vb2_dma_sg_put_userptr, | |
275 | .vaddr = vb2_dma_sg_vaddr, | |
276 | .mmap = vb2_dma_sg_mmap, | |
277 | .num_users = vb2_dma_sg_num_users, | |
278 | .cookie = vb2_dma_sg_cookie, | |
279 | }; | |
280 | EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); | |
281 | ||
282 | MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); | |
283 | MODULE_AUTHOR("Andrzej Pietrasiewicz"); | |
284 | MODULE_LICENSE("GPL"); |