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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
24static int debug;
25module_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
33struct 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
43static void vb2_dma_sg_put(void *buf_priv);
44
45static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
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;
58
59 buf->sg_desc.num_pages = size >> PAGE_SHIFT;
60
61 buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages *
62 sizeof(*buf->sg_desc.sglist));
63 if (!buf->sg_desc.sglist)
64 goto fail_sglist_alloc;
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) {
73 buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO |
74 __GFP_NOWARN | gfp_flags);
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
87 dprintk(1, "%s: Allocated buffer of %d pages\n",
88 __func__, buf->sg_desc.num_pages);
89 return buf;
90
91fail_pages_alloc:
92 while (--i >= 0)
93 __free_page(buf->pages[i]);
94 kfree(buf->pages);
95
96fail_pages_array_alloc:
97 vfree(buf->sg_desc.sglist);
98
99fail_sglist_alloc:
100 kfree(buf);
101 return NULL;
102}
103
104static 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)) {
110 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
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
122static 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
142 buf->sg_desc.sglist = vzalloc(
143 buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
144 if (!buf->sg_desc.sglist)
145 goto userptr_fail_sglist_alloc;
146
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
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,
159 buf->pages,
160 NULL);
161
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
175userptr_fail_get_user_pages:
176 dprintk(1, "get_user_pages requested/got: %d/%d]\n",
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]);
180 kfree(buf->pages);
181
182userptr_fail_pages_array_alloc:
183 vfree(buf->sg_desc.sglist);
184
185userptr_fail_sglist_alloc:
186 kfree(buf);
187 return NULL;
188}
189
190
191
192
193
194static 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
199 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
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
213static 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
226 return buf->vaddr + buf->offset;
227}
228
229static 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
236static 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
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
273static 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
280const 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};
290EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
291
292MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
293MODULE_AUTHOR("Andrzej Pietrasiewicz");
294MODULE_LICENSE("GPL");
295
