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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 | ||
ffdc78ef HV |
24 | static int debug; |
25 | module_param(debug, int, 0644); | |
26 | ||
27 | #define dprintk(level, fmt, arg...) \ | |
28 | do { \ | |
29 | if (debug >= level) \ | |
30 | printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \ | |
31 | } while (0) | |
32 | ||
5ba3f757 AP |
33 | struct vb2_dma_sg_buf { |
34 | void *vaddr; | |
35 | struct page **pages; | |
36 | int write; | |
37 | int offset; | |
38 | struct vb2_dma_sg_desc sg_desc; | |
39 | atomic_t refcount; | |
40 | struct vb2_vmarea_handler handler; | |
41 | }; | |
42 | ||
43 | static void vb2_dma_sg_put(void *buf_priv); | |
44 | ||
b6ba2057 | 45 | static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags) |
5ba3f757 AP |
46 | { |
47 | struct vb2_dma_sg_buf *buf; | |
48 | int i; | |
49 | ||
50 | buf = kzalloc(sizeof *buf, GFP_KERNEL); | |
51 | if (!buf) | |
52 | return NULL; | |
53 | ||
54 | buf->vaddr = NULL; | |
55 | buf->write = 0; | |
56 | buf->offset = 0; | |
57 | buf->sg_desc.size = size; | |
7f841459 MCC |
58 | /* size is already page aligned */ |
59 | buf->sg_desc.num_pages = size >> PAGE_SHIFT; | |
5ba3f757 | 60 | |
fabc6b85 | 61 | buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages * |
5ba3f757 AP |
62 | sizeof(*buf->sg_desc.sglist)); |
63 | if (!buf->sg_desc.sglist) | |
64 | goto fail_sglist_alloc; | |
5ba3f757 AP |
65 | sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); |
66 | ||
67 | buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), | |
68 | GFP_KERNEL); | |
69 | if (!buf->pages) | |
70 | goto fail_pages_array_alloc; | |
71 | ||
72 | for (i = 0; i < buf->sg_desc.num_pages; ++i) { | |
b6ba2057 HV |
73 | buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO | |
74 | __GFP_NOWARN | gfp_flags); | |
5ba3f757 AP |
75 | if (NULL == buf->pages[i]) |
76 | goto fail_pages_alloc; | |
77 | sg_set_page(&buf->sg_desc.sglist[i], | |
78 | buf->pages[i], PAGE_SIZE, 0); | |
79 | } | |
80 | ||
81 | buf->handler.refcount = &buf->refcount; | |
82 | buf->handler.put = vb2_dma_sg_put; | |
83 | buf->handler.arg = buf; | |
84 | ||
85 | atomic_inc(&buf->refcount); | |
86 | ||
ffdc78ef | 87 | dprintk(1, "%s: Allocated buffer of %d pages\n", |
5ba3f757 | 88 | __func__, buf->sg_desc.num_pages); |
5ba3f757 AP |
89 | return buf; |
90 | ||
91 | fail_pages_alloc: | |
92 | while (--i >= 0) | |
93 | __free_page(buf->pages[i]); | |
a9bb36aa | 94 | kfree(buf->pages); |
5ba3f757 AP |
95 | |
96 | fail_pages_array_alloc: | |
97 | vfree(buf->sg_desc.sglist); | |
98 | ||
99 | fail_sglist_alloc: | |
100 | kfree(buf); | |
101 | return NULL; | |
102 | } | |
103 | ||
104 | static void vb2_dma_sg_put(void *buf_priv) | |
105 | { | |
106 | struct vb2_dma_sg_buf *buf = buf_priv; | |
107 | int i = buf->sg_desc.num_pages; | |
108 | ||
109 | if (atomic_dec_and_test(&buf->refcount)) { | |
ffdc78ef | 110 | dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, |
5ba3f757 AP |
111 | buf->sg_desc.num_pages); |
112 | if (buf->vaddr) | |
113 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); | |
114 | vfree(buf->sg_desc.sglist); | |
115 | while (--i >= 0) | |
116 | __free_page(buf->pages[i]); | |
117 | kfree(buf->pages); | |
118 | kfree(buf); | |
119 | } | |
120 | } | |
121 | ||
122 | static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, | |
123 | unsigned long size, int write) | |
124 | { | |
125 | struct vb2_dma_sg_buf *buf; | |
126 | unsigned long first, last; | |
127 | int num_pages_from_user, i; | |
128 | ||
129 | buf = kzalloc(sizeof *buf, GFP_KERNEL); | |
130 | if (!buf) | |
131 | return NULL; | |
132 | ||
133 | buf->vaddr = NULL; | |
134 | buf->write = write; | |
135 | buf->offset = vaddr & ~PAGE_MASK; | |
136 | buf->sg_desc.size = size; | |
137 | ||
138 | first = (vaddr & PAGE_MASK) >> PAGE_SHIFT; | |
139 | last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT; | |
140 | buf->sg_desc.num_pages = last - first + 1; | |
141 | ||
fabc6b85 | 142 | buf->sg_desc.sglist = vzalloc( |
5ba3f757 AP |
143 | buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist)); |
144 | if (!buf->sg_desc.sglist) | |
145 | goto userptr_fail_sglist_alloc; | |
146 | ||
5ba3f757 AP |
147 | sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); |
148 | ||
149 | buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), | |
150 | GFP_KERNEL); | |
151 | if (!buf->pages) | |
152 | goto userptr_fail_pages_array_alloc; | |
153 | ||
5ba3f757 AP |
154 | num_pages_from_user = get_user_pages(current, current->mm, |
155 | vaddr & PAGE_MASK, | |
156 | buf->sg_desc.num_pages, | |
157 | write, | |
158 | 1, /* force */ | |
159 | buf->pages, | |
160 | NULL); | |
b037c0fd | 161 | |
5ba3f757 AP |
162 | if (num_pages_from_user != buf->sg_desc.num_pages) |
163 | goto userptr_fail_get_user_pages; | |
164 | ||
165 | sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0], | |
166 | PAGE_SIZE - buf->offset, buf->offset); | |
167 | size -= PAGE_SIZE - buf->offset; | |
168 | for (i = 1; i < buf->sg_desc.num_pages; ++i) { | |
169 | sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i], | |
170 | min_t(size_t, PAGE_SIZE, size), 0); | |
171 | size -= min_t(size_t, PAGE_SIZE, size); | |
172 | } | |
173 | return buf; | |
174 | ||
175 | userptr_fail_get_user_pages: | |
ffdc78ef | 176 | dprintk(1, "get_user_pages requested/got: %d/%d]\n", |
5ba3f757 AP |
177 | num_pages_from_user, buf->sg_desc.num_pages); |
178 | while (--num_pages_from_user >= 0) | |
179 | put_page(buf->pages[num_pages_from_user]); | |
a9bb36aa | 180 | kfree(buf->pages); |
5ba3f757 AP |
181 | |
182 | userptr_fail_pages_array_alloc: | |
183 | vfree(buf->sg_desc.sglist); | |
184 | ||
185 | userptr_fail_sglist_alloc: | |
186 | kfree(buf); | |
187 | return NULL; | |
188 | } | |
189 | ||
190 | /* | |
191 | * @put_userptr: inform the allocator that a USERPTR buffer will no longer | |
192 | * be used | |
193 | */ | |
194 | static void vb2_dma_sg_put_userptr(void *buf_priv) | |
195 | { | |
196 | struct vb2_dma_sg_buf *buf = buf_priv; | |
197 | int i = buf->sg_desc.num_pages; | |
198 | ||
ffdc78ef | 199 | dprintk(1, "%s: Releasing userspace buffer of %d pages\n", |
5ba3f757 AP |
200 | __func__, buf->sg_desc.num_pages); |
201 | if (buf->vaddr) | |
202 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); | |
203 | while (--i >= 0) { | |
204 | if (buf->write) | |
205 | set_page_dirty_lock(buf->pages[i]); | |
206 | put_page(buf->pages[i]); | |
207 | } | |
208 | vfree(buf->sg_desc.sglist); | |
209 | kfree(buf->pages); | |
210 | kfree(buf); | |
211 | } | |
212 | ||
213 | static void *vb2_dma_sg_vaddr(void *buf_priv) | |
214 | { | |
215 | struct vb2_dma_sg_buf *buf = buf_priv; | |
216 | ||
217 | BUG_ON(!buf); | |
218 | ||
219 | if (!buf->vaddr) | |
220 | buf->vaddr = vm_map_ram(buf->pages, | |
221 | buf->sg_desc.num_pages, | |
222 | -1, | |
223 | PAGE_KERNEL); | |
224 | ||
225 | /* add offset in case userptr is not page-aligned */ | |
226 | return buf->vaddr + buf->offset; | |
227 | } | |
228 | ||
229 | static unsigned int vb2_dma_sg_num_users(void *buf_priv) | |
230 | { | |
231 | struct vb2_dma_sg_buf *buf = buf_priv; | |
232 | ||
233 | return atomic_read(&buf->refcount); | |
234 | } | |
235 | ||
236 | static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) | |
237 | { | |
238 | struct vb2_dma_sg_buf *buf = buf_priv; | |
239 | unsigned long uaddr = vma->vm_start; | |
240 | unsigned long usize = vma->vm_end - vma->vm_start; | |
241 | int i = 0; | |
242 | ||
243 | if (!buf) { | |
244 | printk(KERN_ERR "No memory to map\n"); | |
245 | return -EINVAL; | |
246 | } | |
247 | ||
248 | do { | |
249 | int ret; | |
250 | ||
251 | ret = vm_insert_page(vma, uaddr, buf->pages[i++]); | |
252 | if (ret) { | |
253 | printk(KERN_ERR "Remapping memory, error: %d\n", ret); | |
254 | return ret; | |
255 | } | |
256 | ||
257 | uaddr += PAGE_SIZE; | |
258 | usize -= PAGE_SIZE; | |
259 | } while (usize > 0); | |
260 | ||
261 | ||
262 | /* | |
263 | * Use common vm_area operations to track buffer refcount. | |
264 | */ | |
265 | vma->vm_private_data = &buf->handler; | |
266 | vma->vm_ops = &vb2_common_vm_ops; | |
267 | ||
268 | vma->vm_ops->open(vma); | |
269 | ||
270 | return 0; | |
271 | } | |
272 | ||
273 | static void *vb2_dma_sg_cookie(void *buf_priv) | |
274 | { | |
275 | struct vb2_dma_sg_buf *buf = buf_priv; | |
276 | ||
277 | return &buf->sg_desc; | |
278 | } | |
279 | ||
280 | const struct vb2_mem_ops vb2_dma_sg_memops = { | |
281 | .alloc = vb2_dma_sg_alloc, | |
282 | .put = vb2_dma_sg_put, | |
283 | .get_userptr = vb2_dma_sg_get_userptr, | |
284 | .put_userptr = vb2_dma_sg_put_userptr, | |
285 | .vaddr = vb2_dma_sg_vaddr, | |
286 | .mmap = vb2_dma_sg_mmap, | |
287 | .num_users = vb2_dma_sg_num_users, | |
288 | .cookie = vb2_dma_sg_cookie, | |
289 | }; | |
290 | EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); | |
291 | ||
292 | MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); | |
293 | MODULE_AUTHOR("Andrzej Pietrasiewicz"); | |
294 | MODULE_LICENSE("GPL"); |