aboutsummaryrefslogtreecommitdiff
path: root/drivers/media/video/videobuf-dma-contig.c
blob: c3065c4bcba9fb6019fb664de98f075423348994 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
/*
 * helper functions for physically contiguous capture buffers
 *
 * The functions support hardware lacking scatter gather support
 * (i.e. the buffers must be linear in physical memory)
 *
 * Copyright (c) 2008 Magnus Damm
 *
 * Based on videobuf-vmalloc.c,
 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/dma-mapping.h>
#include <linux/sched.h>
#include <media/videobuf-dma-contig.h>

struct videobuf_dma_contig_memory {
	u32 magic;
	void *vaddr;
	dma_addr_t dma_handle;
	unsigned long size;
	int is_userptr;
};

#define MAGIC_DC_MEM 0x0733ac61
#define MAGIC_CHECK(is, should)						    \
	if (unlikely((is) != (should)))	{				    \
		pr_err("magic mismatch: %x expected %x\n", (is), (should)); \
		BUG();							    \
	}

static void
videobuf_vm_open(struct vm_area_struct *vma)
{
	struct videobuf_mapping *map = vma->vm_private_data;

	dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n",
		map, map->count, vma->vm_start, vma->vm_end);

	map->count++;
}

static void videobuf_vm_close(struct vm_area_struct *vma)
{
	struct videobuf_mapping *map = vma->vm_private_data;
	struct videobuf_queue *q = map->q;
	int i;

	dev_dbg(map->q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n",
		map, map->count, vma->vm_start, vma->vm_end);

	map->count--;
	if (0 == map->count) {
		struct videobuf_dma_contig_memory *mem;

		dev_dbg(map->q->dev, "munmap %p q=%p\n", map, q);
		mutex_lock(&q->vb_lock);

		/* We need first to cancel streams, before unmapping */
		if (q->streaming)
			videobuf_queue_cancel(q);

		for (i = 0; i < VIDEO_MAX_FRAME; i++) {
			if (NULL == q->bufs[i])
				continue;

			if (q->bufs[i]->map != map)
				continue;

			mem = q->bufs[i]->priv;
			if (mem) {
				/* This callback is called only if kernel has
				   allocated memory and this memory is mmapped.
				   In this case, memory should be freed,
				   in order to do memory unmap.
				 */

				MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

				/* vfree is not atomic - can't be
				   called with IRQ's disabled
				 */
				dev_dbg(map->q->dev, "buf[%d] freeing %p\n",
					i, mem->vaddr);

				dma_free_coherent(q->dev, mem->size,
						  mem->vaddr, mem->dma_handle);
				mem->vaddr = NULL;
			}

			q->bufs[i]->map   = NULL;
			q->bufs[i]->baddr = 0;
		}

		kfree(map);

		mutex_unlock(&q->vb_lock);
	}
}

static const struct vm_operations_struct videobuf_vm_ops = {
	.open     = videobuf_vm_open,
	.close    = videobuf_vm_close,
};

/**
 * videobuf_dma_contig_user_put() - reset pointer to user space buffer
 * @mem: per-buffer private videobuf-dma-contig data
 *
 * This function resets the user space pointer
 */
static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
{
	mem->is_userptr = 0;
	mem->dma_handle = 0;
	mem->size = 0;
}

/**
 * videobuf_dma_contig_user_get() - setup user space memory pointer
 * @mem: per-buffer private videobuf-dma-contig data
 * @vb: video buffer to map
 *
 * This function validates and sets up a pointer to user space memory.
 * Only physically contiguous pfn-mapped memory is accepted.
 *
 * Returns 0 if successful.
 */
static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
					struct videobuf_buffer *vb)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned long prev_pfn, this_pfn;
	unsigned long pages_done, user_address;
	int ret;

	mem->size = PAGE_ALIGN(vb->size);
	mem->is_userptr = 0;
	ret = -EINVAL;

	down_read(&mm->mmap_sem);

	vma = find_vma(mm, vb->baddr);
	if (!vma)
		goto out_up;

	if ((vb->baddr + mem->size) > vma->vm_end)
		goto out_up;

	pages_done = 0;
	prev_pfn = 0; /* kill warning */
	user_address = vb->baddr;

	while (pages_done < (mem->size >> PAGE_SHIFT)) {
		ret = follow_pfn(vma, user_address, &this_pfn);
		if (ret)
			break;

		if (pages_done == 0)
			mem->dma_handle = this_pfn << PAGE_SHIFT;
		else if (this_pfn != (prev_pfn + 1))
			ret = -EFAULT;

		if (ret)
			break;

		prev_pfn = this_pfn;
		user_address += PAGE_SIZE;
		pages_done++;
	}

	if (!ret)
		mem->is_userptr = 1;

 out_up:
	up_read(&current->mm->mmap_sem);

	return ret;
}

static void *__videobuf_alloc(size_t size)
{
	struct videobuf_dma_contig_memory *mem;
	struct videobuf_buffer *vb;

	vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
	if (vb) {
		mem = vb->priv = ((char *)vb) + size;
		mem->magic = MAGIC_DC_MEM;
	}

	return vb;
}

static void *__videobuf_to_vmalloc(struct videobuf_buffer *buf)
{
	struct videobuf_dma_contig_memory *mem = buf->priv;

	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

	return mem->vaddr;
}

static int __videobuf_iolock(struct videobuf_queue *q,
			     struct videobuf_buffer *vb,
			     struct v4l2_framebuffer *fbuf)
{
	struct videobuf_dma_contig_memory *mem = vb->priv;

	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

	switch (vb->memory) {
	case V4L2_MEMORY_MMAP:
		dev_dbg(q->dev, "%s memory method MMAP\n", __func__);

		/* All handling should be done by __videobuf_mmap_mapper() */
		if (!mem->vaddr) {
			dev_err(q->dev, "memory is not alloced/mmapped.\n");
			return -EINVAL;
		}
		break;
	case V4L2_MEMORY_USERPTR:
		dev_dbg(q->dev, "%s memory method USERPTR\n", __func__);

		/* handle pointer from user space */
		if (vb->baddr)
			return videobuf_dma_contig_user_get(mem, vb);

		/* allocate memory for the read() method */
		mem->size = PAGE_ALIGN(vb->size);
		mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
						&mem->dma_handle, GFP_KERNEL);
		if (!mem->vaddr) {
			dev_err(q->dev, "dma_alloc_coherent %ld failed\n",
					 mem->size);
			return -ENOMEM;
		}

		dev_dbg(q->dev, "dma_alloc_coherent data is at %p (%ld)\n",
			mem->vaddr, mem->size);
		break;
	case V4L2_MEMORY_OVERLAY:
	default:
		dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n",
			__func__);
		return -EINVAL;
	}

	return 0;
}

static int __videobuf_mmap_free(struct videobuf_queue *q)
{
	unsigned int i;

	dev_dbg(q->dev, "%s\n", __func__);
	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (q->bufs[i] && q->bufs[i]->map)
			return -EBUSY;
	}

	return 0;
}

static int __videobuf_mmap_mapper(struct videobuf_queue *q,
				  struct vm_area_struct *vma)
{
	struct videobuf_dma_contig_memory *mem;
	struct videobuf_mapping *map;
	unsigned int first;
	int retval;
	unsigned long size, offset = vma->vm_pgoff << PAGE_SHIFT;

	dev_dbg(q->dev, "%s\n", __func__);
	if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	/* look for first buffer to map */
	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
		if (!q->bufs[first])
			continue;

		if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
			continue;
		if (q->bufs[first]->boff == offset)
			break;
	}
	if (VIDEO_MAX_FRAME == first) {
		dev_dbg(q->dev, "invalid user space offset [offset=0x%lx]\n",
			offset);
		return -EINVAL;
	}

	/* create mapping + update buffer list */
	map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
	if (!map)
		return -ENOMEM;

	q->bufs[first]->map = map;
	map->start = vma->vm_start;
	map->end = vma->vm_end;
	map->q = q;

	q->bufs[first]->baddr = vma->vm_start;

	mem = q->bufs[first]->priv;
	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

	mem->size = PAGE_ALIGN(q->bufs[first]->bsize);
	mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
					&mem->dma_handle, GFP_KERNEL);
	if (!mem->vaddr) {
		dev_err(q->dev, "dma_alloc_coherent size %ld failed\n",
			mem->size);
		goto error;
	}
	dev_dbg(q->dev, "dma_alloc_coherent data is at addr %p (size %ld)\n",
		mem->vaddr, mem->size);

	/* Try to remap memory */

	size = vma->vm_end - vma->vm_start;
	size = (size < mem->size) ? size : mem->size;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	retval = remap_pfn_range(vma, vma->vm_start,
				 mem->dma_handle >> PAGE_SHIFT,
				 size, vma->vm_page_prot);
	if (retval) {
		dev_err(q->dev, "mmap: remap failed with error %d. ", retval);
		dma_free_coherent(q->dev, mem->size,
				  mem->vaddr, mem->dma_handle);
		goto error;
	}

	vma->vm_ops          = &videobuf_vm_ops;
	vma->vm_flags       |= VM_DONTEXPAND;
	vma->vm_private_data = map;

	dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
		map, q, vma->vm_start, vma->vm_end,
		(long int) q->bufs[first]->bsize,
		vma->vm_pgoff, first);

	videobuf_vm_open(vma);

	return 0;

error:
	kfree(map);
	return -ENOMEM;
}

static int __videobuf_copy_to_user(struct videobuf_queue *q,
				   char __user *data, size_t count,
				   int nonblocking)
{
	struct videobuf_dma_contig_memory *mem = q->read_buf->priv;
	void *vaddr;

	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
	BUG_ON(!mem->vaddr);

	/* copy to userspace */
	if (count > q->read_buf->size - q->read_off)
		count = q->read_buf->size - q->read_off;

	vaddr = mem->vaddr;

	if (copy_to_user(data, vaddr + q->read_off, count))
		return -EFAULT;

	return count;
}

static int __videobuf_copy_stream(struct videobuf_queue *q,
				  char __user *data, size_t count, size_t pos,
				  int vbihack, int nonblocking)
{
	unsigned int  *fc;
	struct videobuf_dma_contig_memory *mem = q->read_buf->priv;

	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

	if (vbihack) {
		/* dirty, undocumented hack -- pass the frame counter
			* within the last four bytes of each vbi data block.
			* We need that one to maintain backward compatibility
			* to all vbi decoding software out there ... */
		fc = (unsigned int *)mem->vaddr;
		fc += (q->read_buf->size >> 2) - 1;
		*fc = q->read_buf->field_count >> 1;
		dev_dbg(q->dev, "vbihack: %d\n", *fc);
	}

	/* copy stuff using the common method */
	count = __videobuf_copy_to_user(q, data, count, nonblocking);

	if ((count == -EFAULT) && (pos == 0))
		return -EFAULT;

	return count;
}

static struct videobuf_qtype_ops qops = {
	.magic        = MAGIC_QTYPE_OPS,

	.alloc        = __videobuf_alloc,
	.iolock       = __videobuf_iolock,
	.mmap_free    = __videobuf_mmap_free,
	.mmap_mapper  = __videobuf_mmap_mapper,
	.video_copy_to_user = __videobuf_copy_to_user,
	.copy_stream  = __videobuf_copy_stream,
	.vmalloc      = __videobuf_to_vmalloc,
};

void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
				    struct videobuf_queue_ops *ops,
				    struct device *dev,
				    spinlock_t *irqlock,
				    enum v4l2_buf_type type,
				    enum v4l2_field field,
				    unsigned int msize,
				    void *priv)
{
	videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
				 priv, &qops);
}
EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init);

dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
{
	struct videobuf_dma_contig_memory *mem = buf->priv;

	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

	return mem->dma_handle;
}
EXPORT_SYMBOL_GPL(videobuf_to_dma_contig);

void videobuf_dma_contig_free(struct videobuf_queue *q,
			      struct videobuf_buffer *buf)
{
	struct videobuf_dma_contig_memory *mem = buf->priv;

	/* mmapped memory can't be freed here, otherwise mmapped region
	   would be released, while still needed. In this case, the memory
	   release should happen inside videobuf_vm_close().
	   So, it should free memory only if the memory were allocated for
	   read() operation.
	 */
	if (buf->memory != V4L2_MEMORY_USERPTR)
		return;

	if (!mem)
		return;

	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

	/* handle user space pointer case */
	if (buf->baddr) {
		videobuf_dma_contig_user_put(mem);
		return;
	}

	/* read() method */
	dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle);
	mem->vaddr = NULL;
}
EXPORT_SYMBOL_GPL(videobuf_dma_contig_free);

MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers");
MODULE_AUTHOR("Magnus Damm");
MODULE_LICENSE("GPL");