summaryrefslogtreecommitdiff
path: root/drivers/media/v4l2-core/videobuf-vmalloc.c
blob: 85c7090606d609603e62ac9b16104fe99ebc12ca (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * helper functions for vmalloc video4linux capture buffers
 *
 * The functions expect the hardware being able to scatter gather
 * (i.e. the buffers are not linear in physical memory, but fragmented
 * into PAGE_SIZE chunks).  They also assume the driver does not need
 * to touch the video data.
 *
 * (c) 2007 Mauro Carvalho Chehab <mchehab@kernel.org>
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/pgtable.h>

#include <linux/pci.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <asm/page.h>

#include <media/videobuf-vmalloc.h>

#define MAGIC_DMABUF   0x17760309
#define MAGIC_VMAL_MEM 0x18221223

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

static int debug;
module_param(debug, int, 0644);

MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@kernel.org>");
MODULE_LICENSE("GPL");

#define dprintk(level, fmt, arg...)					\
	if (debug >= level)						\
		printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg)


/***************************************************************************/

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

	dprintk(2, "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;

	dprintk(2, "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_vmalloc_memory *mem;

		dprintk(1, "munmap %p q=%p\n", map, q);
		videobuf_queue_lock(q);

		/* 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_VMAL_MEM);

				/* vfree is not atomic - can't be
				   called with IRQ's disabled
				 */
				dprintk(1, "%s: buf[%d] freeing (%p)\n",
					__func__, i, mem->vaddr);

				vfree(mem->vaddr);
				mem->vaddr = NULL;
			}

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

		kfree(map);

		videobuf_queue_unlock(q);
	}

	return;
}

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

/* ---------------------------------------------------------------------
 * vmalloc handlers for the generic methods
 */

/* Allocated area consists on 3 parts:
	struct video_buffer
	struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
	struct videobuf_dma_sg_memory
 */

static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
{
	struct videobuf_vmalloc_memory *mem;
	struct videobuf_buffer *vb;

	vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
	if (!vb)
		return vb;

	mem = vb->priv = ((char *)vb) + size;
	mem->magic = MAGIC_VMAL_MEM;

	dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
		__func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
		mem, (long)sizeof(*mem));

	return vb;
}

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

	BUG_ON(!mem);

	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

	switch (vb->memory) {
	case V4L2_MEMORY_MMAP:
		dprintk(1, "%s memory method MMAP\n", __func__);

		/* All handling should be done by __videobuf_mmap_mapper() */
		if (!mem->vaddr) {
			printk(KERN_ERR "memory is not allocated/mmapped.\n");
			return -EINVAL;
		}
		break;
	case V4L2_MEMORY_USERPTR:
		pages = PAGE_ALIGN(vb->size);

		dprintk(1, "%s memory method USERPTR\n", __func__);

		if (vb->baddr) {
			printk(KERN_ERR "USERPTR is currently not supported\n");
			return -EINVAL;
		}

		/* The only USERPTR currently supported is the one needed for
		 * read() method.
		 */

		mem->vaddr = vmalloc_user(pages);
		if (!mem->vaddr) {
			printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
			return -ENOMEM;
		}
		dprintk(1, "vmalloc is at addr %p (%d pages)\n",
			mem->vaddr, pages);
		break;
	case V4L2_MEMORY_OVERLAY:
	default:
		dprintk(1, "%s memory method OVERLAY/unknown\n", __func__);

		/* Currently, doesn't support V4L2_MEMORY_OVERLAY */
		printk(KERN_ERR "Memory method currently unsupported.\n");
		return -EINVAL;
	}

	return 0;
}

static int __videobuf_mmap_mapper(struct videobuf_queue *q,
				  struct videobuf_buffer *buf,
				  struct vm_area_struct *vma)
{
	struct videobuf_vmalloc_memory *mem;
	struct videobuf_mapping *map;
	int retval, pages;

	dprintk(1, "%s\n", __func__);

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

	buf->map = map;
	map->q     = q;

	buf->baddr = vma->vm_start;

	mem = buf->priv;
	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

	pages = PAGE_ALIGN(vma->vm_end - vma->vm_start);
	mem->vaddr = vmalloc_user(pages);
	if (!mem->vaddr) {
		printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
		goto error;
	}
	dprintk(1, "vmalloc is at addr %p (%d pages)\n", mem->vaddr, pages);

	/* Try to remap memory */
	retval = remap_vmalloc_range(vma, mem->vaddr, 0);
	if (retval < 0) {
		printk(KERN_ERR "mmap: remap failed with error %d. ", retval);
		vfree(mem->vaddr);
		goto error;
	}

	vma->vm_ops          = &videobuf_vm_ops;
	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP);
	vma->vm_private_data = map;

	dprintk(1, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
		map, q, vma->vm_start, vma->vm_end,
		(long int)buf->bsize,
		vma->vm_pgoff, buf->i);

	videobuf_vm_open(vma);

	return 0;

error:
	mem = NULL;
	kfree(map);
	return -ENOMEM;
}

static struct videobuf_qtype_ops qops = {
	.magic        = MAGIC_QTYPE_OPS,

	.alloc_vb     = __videobuf_alloc_vb,
	.iolock       = __videobuf_iolock,
	.mmap_mapper  = __videobuf_mmap_mapper,
	.vaddr        = videobuf_to_vmalloc,
};

void videobuf_queue_vmalloc_init(struct videobuf_queue *q,
			 const 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,
			 struct mutex *ext_lock)
{
	videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
				 priv, &qops, ext_lock);
}
EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);

void *videobuf_to_vmalloc(struct videobuf_buffer *buf)
{
	struct videobuf_vmalloc_memory *mem = buf->priv;
	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

	return mem->vaddr;
}
EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);

void videobuf_vmalloc_free(struct videobuf_buffer *buf)
{
	struct videobuf_vmalloc_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) || buf->baddr)
		return;

	if (!mem)
		return;

	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

	vfree(mem->vaddr);
	mem->vaddr = NULL;

	return;
}
EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);