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/videobuf-dma-contig.c | |
parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) |
Diffstat (limited to 'drivers/media/video/videobuf-dma-contig.c')
-rw-r--r-- | drivers/media/video/videobuf-dma-contig.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/drivers/media/video/videobuf-dma-contig.c b/drivers/media/video/videobuf-dma-contig.c new file mode 100644 index 00000000000..c9691115f2d --- /dev/null +++ b/drivers/media/video/videobuf-dma-contig.c | |||
@@ -0,0 +1,400 @@ | |||
1 | /* | ||
2 | * helper functions for physically contiguous capture buffers | ||
3 | * | ||
4 | * The functions support hardware lacking scatter gather support | ||
5 | * (i.e. the buffers must be linear in physical memory) | ||
6 | * | ||
7 | * Copyright (c) 2008 Magnus Damm | ||
8 | * | ||
9 | * Based on videobuf-vmalloc.c, | ||
10 | * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org> | ||
11 | * | ||
12 | * This program is free software; you can redistribute it and/or modify | ||
13 | * it under the terms of the GNU General Public License as published by | ||
14 | * the Free Software Foundation; either version 2 | ||
15 | */ | ||
16 | |||
17 | #include <linux/init.h> | ||
18 | #include <linux/module.h> | ||
19 | #include <linux/mm.h> | ||
20 | #include <linux/pagemap.h> | ||
21 | #include <linux/dma-mapping.h> | ||
22 | #include <linux/sched.h> | ||
23 | #include <linux/slab.h> | ||
24 | #include <media/videobuf-dma-contig.h> | ||
25 | |||
26 | struct videobuf_dma_contig_memory { | ||
27 | u32 magic; | ||
28 | void *vaddr; | ||
29 | dma_addr_t dma_handle; | ||
30 | unsigned long size; | ||
31 | }; | ||
32 | |||
33 | #define MAGIC_DC_MEM 0x0733ac61 | ||
34 | #define MAGIC_CHECK(is, should) \ | ||
35 | if (unlikely((is) != (should))) { \ | ||
36 | pr_err("magic mismatch: %x expected %x\n", (is), (should)); \ | ||
37 | BUG(); \ | ||
38 | } | ||
39 | |||
40 | static void | ||
41 | videobuf_vm_open(struct vm_area_struct *vma) | ||
42 | { | ||
43 | struct videobuf_mapping *map = vma->vm_private_data; | ||
44 | |||
45 | dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n", | ||
46 | map, map->count, vma->vm_start, vma->vm_end); | ||
47 | |||
48 | map->count++; | ||
49 | } | ||
50 | |||
51 | static void videobuf_vm_close(struct vm_area_struct *vma) | ||
52 | { | ||
53 | struct videobuf_mapping *map = vma->vm_private_data; | ||
54 | struct videobuf_queue *q = map->q; | ||
55 | int i; | ||
56 | |||
57 | dev_dbg(q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n", | ||
58 | map, map->count, vma->vm_start, vma->vm_end); | ||
59 | |||
60 | map->count--; | ||
61 | if (0 == map->count) { | ||
62 | struct videobuf_dma_contig_memory *mem; | ||
63 | |||
64 | dev_dbg(q->dev, "munmap %p q=%p\n", map, q); | ||
65 | videobuf_queue_lock(q); | ||
66 | |||
67 | /* We need first to cancel streams, before unmapping */ | ||
68 | if (q->streaming) | ||
69 | videobuf_queue_cancel(q); | ||
70 | |||
71 | for (i = 0; i < VIDEO_MAX_FRAME; i++) { | ||
72 | if (NULL == q->bufs[i]) | ||
73 | continue; | ||
74 | |||
75 | if (q->bufs[i]->map != map) | ||
76 | continue; | ||
77 | |||
78 | mem = q->bufs[i]->priv; | ||
79 | if (mem) { | ||
80 | /* This callback is called only if kernel has | ||
81 | allocated memory and this memory is mmapped. | ||
82 | In this case, memory should be freed, | ||
83 | in order to do memory unmap. | ||
84 | */ | ||
85 | |||
86 | MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); | ||
87 | |||
88 | /* vfree is not atomic - can't be | ||
89 | called with IRQ's disabled | ||
90 | */ | ||
91 | dev_dbg(q->dev, "buf[%d] freeing %p\n", | ||
92 | i, mem->vaddr); | ||
93 | |||
94 | dma_free_coherent(q->dev, mem->size, | ||
95 | mem->vaddr, mem->dma_handle); | ||
96 | mem->vaddr = NULL; | ||
97 | } | ||
98 | |||
99 | q->bufs[i]->map = NULL; | ||
100 | q->bufs[i]->baddr = 0; | ||
101 | } | ||
102 | |||
103 | kfree(map); | ||
104 | |||
105 | videobuf_queue_unlock(q); | ||
106 | } | ||
107 | } | ||
108 | |||
109 | static const struct vm_operations_struct videobuf_vm_ops = { | ||
110 | .open = videobuf_vm_open, | ||
111 | .close = videobuf_vm_close, | ||
112 | }; | ||
113 | |||
114 | /** | ||
115 | * videobuf_dma_contig_user_put() - reset pointer to user space buffer | ||
116 | * @mem: per-buffer private videobuf-dma-contig data | ||
117 | * | ||
118 | * This function resets the user space pointer | ||
119 | */ | ||
120 | static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem) | ||
121 | { | ||
122 | mem->dma_handle = 0; | ||
123 | mem->size = 0; | ||
124 | } | ||
125 | |||
126 | /** | ||
127 | * videobuf_dma_contig_user_get() - setup user space memory pointer | ||
128 | * @mem: per-buffer private videobuf-dma-contig data | ||
129 | * @vb: video buffer to map | ||
130 | * | ||
131 | * This function validates and sets up a pointer to user space memory. | ||
132 | * Only physically contiguous pfn-mapped memory is accepted. | ||
133 | * | ||
134 | * Returns 0 if successful. | ||
135 | */ | ||
136 | static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem, | ||
137 | struct videobuf_buffer *vb) | ||
138 | { | ||
139 | struct mm_struct *mm = current->mm; | ||
140 | struct vm_area_struct *vma; | ||
141 | unsigned long prev_pfn, this_pfn; | ||
142 | unsigned long pages_done, user_address; | ||
143 | unsigned int offset; | ||
144 | int ret; | ||
145 | |||
146 | offset = vb->baddr & ~PAGE_MASK; | ||
147 | mem->size = PAGE_ALIGN(vb->size + offset); | ||
148 | ret = -EINVAL; | ||
149 | |||
150 | down_read(&mm->mmap_sem); | ||
151 | |||
152 | vma = find_vma(mm, vb->baddr); | ||
153 | if (!vma) | ||
154 | goto out_up; | ||
155 | |||
156 | if ((vb->baddr + mem->size) > vma->vm_end) | ||
157 | goto out_up; | ||
158 | |||
159 | pages_done = 0; | ||
160 | prev_pfn = 0; /* kill warning */ | ||
161 | user_address = vb->baddr; | ||
162 | |||
163 | while (pages_done < (mem->size >> PAGE_SHIFT)) { | ||
164 | ret = follow_pfn(vma, user_address, &this_pfn); | ||
165 | if (ret) | ||
166 | break; | ||
167 | |||
168 | if (pages_done == 0) | ||
169 | mem->dma_handle = (this_pfn << PAGE_SHIFT) + offset; | ||
170 | else if (this_pfn != (prev_pfn + 1)) | ||
171 | ret = -EFAULT; | ||
172 | |||
173 | if (ret) | ||
174 | break; | ||
175 | |||
176 | prev_pfn = this_pfn; | ||
177 | user_address += PAGE_SIZE; | ||
178 | pages_done++; | ||
179 | } | ||
180 | |||
181 | out_up: | ||
182 | up_read(¤t->mm->mmap_sem); | ||
183 | |||
184 | return ret; | ||
185 | } | ||
186 | |||
187 | static struct videobuf_buffer *__videobuf_alloc_vb(size_t size) | ||
188 | { | ||
189 | struct videobuf_dma_contig_memory *mem; | ||
190 | struct videobuf_buffer *vb; | ||
191 | |||
192 | vb = kzalloc(size + sizeof(*mem), GFP_KERNEL); | ||
193 | if (vb) { | ||
194 | mem = vb->priv = ((char *)vb) + size; | ||
195 | mem->magic = MAGIC_DC_MEM; | ||
196 | } | ||
197 | |||
198 | return vb; | ||
199 | } | ||
200 | |||
201 | static void *__videobuf_to_vaddr(struct videobuf_buffer *buf) | ||
202 | { | ||
203 | struct videobuf_dma_contig_memory *mem = buf->priv; | ||
204 | |||
205 | BUG_ON(!mem); | ||
206 | MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); | ||
207 | |||
208 | return mem->vaddr; | ||
209 | } | ||
210 | |||
211 | static int __videobuf_iolock(struct videobuf_queue *q, | ||
212 | struct videobuf_buffer *vb, | ||
213 | struct v4l2_framebuffer *fbuf) | ||
214 | { | ||
215 | struct videobuf_dma_contig_memory *mem = vb->priv; | ||
216 | |||
217 | BUG_ON(!mem); | ||
218 | MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); | ||
219 | |||
220 | switch (vb->memory) { | ||
221 | case V4L2_MEMORY_MMAP: | ||
222 | dev_dbg(q->dev, "%s memory method MMAP\n", __func__); | ||
223 | |||
224 | /* All handling should be done by __videobuf_mmap_mapper() */ | ||
225 | if (!mem->vaddr) { | ||
226 | dev_err(q->dev, "memory is not alloced/mmapped.\n"); | ||
227 | return -EINVAL; | ||
228 | } | ||
229 | break; | ||
230 | case V4L2_MEMORY_USERPTR: | ||
231 | dev_dbg(q->dev, "%s memory method USERPTR\n", __func__); | ||
232 | |||
233 | /* handle pointer from user space */ | ||
234 | if (vb->baddr) | ||
235 | return videobuf_dma_contig_user_get(mem, vb); | ||
236 | |||
237 | /* allocate memory for the read() method */ | ||
238 | mem->size = PAGE_ALIGN(vb->size); | ||
239 | mem->vaddr = dma_alloc_coherent(q->dev, mem->size, | ||
240 | &mem->dma_handle, GFP_KERNEL); | ||
241 | if (!mem->vaddr) { | ||
242 | dev_err(q->dev, "dma_alloc_coherent %ld failed\n", | ||
243 | mem->size); | ||
244 | return -ENOMEM; | ||
245 | } | ||
246 | |||
247 | dev_dbg(q->dev, "dma_alloc_coherent data is at %p (%ld)\n", | ||
248 | mem->vaddr, mem->size); | ||
249 | break; | ||
250 | case V4L2_MEMORY_OVERLAY: | ||
251 | default: | ||
252 | dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n", | ||
253 | __func__); | ||
254 | return -EINVAL; | ||
255 | } | ||
256 | |||
257 | return 0; | ||
258 | } | ||
259 | |||
260 | static int __videobuf_mmap_mapper(struct videobuf_queue *q, | ||
261 | struct videobuf_buffer *buf, | ||
262 | struct vm_area_struct *vma) | ||
263 | { | ||
264 | struct videobuf_dma_contig_memory *mem; | ||
265 | struct videobuf_mapping *map; | ||
266 | int retval; | ||
267 | unsigned long size; | ||
268 | |||
269 | dev_dbg(q->dev, "%s\n", __func__); | ||
270 | |||
271 | /* create mapping + update buffer list */ | ||
272 | map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL); | ||
273 | if (!map) | ||
274 | return -ENOMEM; | ||
275 | |||
276 | buf->map = map; | ||
277 | map->q = q; | ||
278 | |||
279 | buf->baddr = vma->vm_start; | ||
280 | |||
281 | mem = buf->priv; | ||
282 | BUG_ON(!mem); | ||
283 | MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); | ||
284 | |||
285 | mem->size = PAGE_ALIGN(buf->bsize); | ||
286 | mem->vaddr = dma_alloc_coherent(q->dev, mem->size, | ||
287 | &mem->dma_handle, GFP_KERNEL); | ||
288 | if (!mem->vaddr) { | ||
289 | dev_err(q->dev, "dma_alloc_coherent size %ld failed\n", | ||
290 | mem->size); | ||
291 | goto error; | ||
292 | } | ||
293 | dev_dbg(q->dev, "dma_alloc_coherent data is at addr %p (size %ld)\n", | ||
294 | mem->vaddr, mem->size); | ||
295 | |||
296 | /* Try to remap memory */ | ||
297 | |||
298 | size = vma->vm_end - vma->vm_start; | ||
299 | size = (size < mem->size) ? size : mem->size; | ||
300 | |||
301 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | ||
302 | retval = remap_pfn_range(vma, vma->vm_start, | ||
303 | mem->dma_handle >> PAGE_SHIFT, | ||
304 | size, vma->vm_page_prot); | ||
305 | if (retval) { | ||
306 | dev_err(q->dev, "mmap: remap failed with error %d. ", retval); | ||
307 | dma_free_coherent(q->dev, mem->size, | ||
308 | mem->vaddr, mem->dma_handle); | ||
309 | goto error; | ||
310 | } | ||
311 | |||
312 | vma->vm_ops = &videobuf_vm_ops; | ||
313 | vma->vm_flags |= VM_DONTEXPAND; | ||
314 | vma->vm_private_data = map; | ||
315 | |||
316 | dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n", | ||
317 | map, q, vma->vm_start, vma->vm_end, | ||
318 | (long int)buf->bsize, | ||
319 | vma->vm_pgoff, buf->i); | ||
320 | |||
321 | videobuf_vm_open(vma); | ||
322 | |||
323 | return 0; | ||
324 | |||
325 | error: | ||
326 | kfree(map); | ||
327 | return -ENOMEM; | ||
328 | } | ||
329 | |||
330 | static struct videobuf_qtype_ops qops = { | ||
331 | .magic = MAGIC_QTYPE_OPS, | ||
332 | |||
333 | .alloc_vb = __videobuf_alloc_vb, | ||
334 | .iolock = __videobuf_iolock, | ||
335 | .mmap_mapper = __videobuf_mmap_mapper, | ||
336 | .vaddr = __videobuf_to_vaddr, | ||
337 | }; | ||
338 | |||
339 | void videobuf_queue_dma_contig_init(struct videobuf_queue *q, | ||
340 | const struct videobuf_queue_ops *ops, | ||
341 | struct device *dev, | ||
342 | spinlock_t *irqlock, | ||
343 | enum v4l2_buf_type type, | ||
344 | enum v4l2_field field, | ||
345 | unsigned int msize, | ||
346 | void *priv, | ||
347 | struct mutex *ext_lock) | ||
348 | { | ||
349 | videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, | ||
350 | priv, &qops, ext_lock); | ||
351 | } | ||
352 | EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init); | ||
353 | |||
354 | dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf) | ||
355 | { | ||
356 | struct videobuf_dma_contig_memory *mem = buf->priv; | ||
357 | |||
358 | BUG_ON(!mem); | ||
359 | MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); | ||
360 | |||
361 | return mem->dma_handle; | ||
362 | } | ||
363 | EXPORT_SYMBOL_GPL(videobuf_to_dma_contig); | ||
364 | |||
365 | void videobuf_dma_contig_free(struct videobuf_queue *q, | ||
366 | struct videobuf_buffer *buf) | ||
367 | { | ||
368 | struct videobuf_dma_contig_memory *mem = buf->priv; | ||
369 | |||
370 | /* mmapped memory can't be freed here, otherwise mmapped region | ||
371 | would be released, while still needed. In this case, the memory | ||
372 | release should happen inside videobuf_vm_close(). | ||
373 | So, it should free memory only if the memory were allocated for | ||
374 | read() operation. | ||
375 | */ | ||
376 | if (buf->memory != V4L2_MEMORY_USERPTR) | ||
377 | return; | ||
378 | |||
379 | if (!mem) | ||
380 | return; | ||
381 | |||
382 | MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); | ||
383 | |||
384 | /* handle user space pointer case */ | ||
385 | if (buf->baddr) { | ||
386 | videobuf_dma_contig_user_put(mem); | ||
387 | return; | ||
388 | } | ||
389 | |||
390 | /* read() method */ | ||
391 | if (mem->vaddr) { | ||
392 | dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle); | ||
393 | mem->vaddr = NULL; | ||
394 | } | ||
395 | } | ||
396 | EXPORT_SYMBOL_GPL(videobuf_dma_contig_free); | ||
397 | |||
398 | MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers"); | ||
399 | MODULE_AUTHOR("Magnus Damm"); | ||
400 | MODULE_LICENSE("GPL"); | ||