2 * helper functions for vmalloc video4linux capture buffers
4 * The functions expect the hardware being able to scatter gather
5 * (i.e. the buffers are not linear in physical memory, but fragmented
6 * into PAGE_SIZE chunks). They also assume the driver does not need
7 * to touch the video data.
9 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/slab.h>
20 #include <linux/interrupt.h>
22 #include <linux/pci.h>
23 #include <linux/vmalloc.h>
24 #include <linux/pagemap.h>
26 #include <asm/pgtable.h>
28 #include <media/videobuf-vmalloc.h>
30 #define MAGIC_DMABUF 0x17760309
31 #define MAGIC_VMAL_MEM 0x18221223
33 #define MAGIC_CHECK(is, should) \
34 if (unlikely((is) != (should))) { \
35 printk(KERN_ERR "magic mismatch: %x (expected %x)\n", \
41 module_param(debug, int, 0644);
43 MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
44 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
45 MODULE_LICENSE("GPL");
47 #define dprintk(level, fmt, arg...) \
49 printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg)
52 /***************************************************************************/
54 static void videobuf_vm_open(struct vm_area_struct *vma)
56 struct videobuf_mapping *map = vma->vm_private_data;
58 dprintk(2, "vm_open %p [count=%u,vma=%08lx-%08lx]\n", map,
59 map->count, vma->vm_start, vma->vm_end);
64 static void videobuf_vm_close(struct vm_area_struct *vma)
66 struct videobuf_mapping *map = vma->vm_private_data;
67 struct videobuf_queue *q = map->q;
70 dprintk(2, "vm_close %p [count=%u,vma=%08lx-%08lx]\n", map,
71 map->count, vma->vm_start, vma->vm_end);
74 if (0 == map->count) {
75 struct videobuf_vmalloc_memory *mem;
77 dprintk(1, "munmap %p q=%p\n", map, q);
78 mutex_lock(&q->vb_lock);
80 /* We need first to cancel streams, before unmapping */
82 videobuf_queue_cancel(q);
84 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
85 if (NULL == q->bufs[i])
88 if (q->bufs[i]->map != map)
91 mem = q->bufs[i]->priv;
93 /* This callback is called only if kernel has
94 allocated memory and this memory is mmapped.
95 In this case, memory should be freed,
96 in order to do memory unmap.
99 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
101 /* vfree is not atomic - can't be
102 called with IRQ's disabled
104 dprintk(1, "%s: buf[%d] freeing (%p)\n",
105 __func__, i, mem->vmalloc);
111 q->bufs[i]->map = NULL;
112 q->bufs[i]->baddr = 0;
117 mutex_unlock(&q->vb_lock);
123 static const struct vm_operations_struct videobuf_vm_ops = {
124 .open = videobuf_vm_open,
125 .close = videobuf_vm_close,
128 /* ---------------------------------------------------------------------
129 * vmalloc handlers for the generic methods
132 /* Allocated area consists on 3 parts:
134 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
135 struct videobuf_dma_sg_memory
138 static void *__videobuf_alloc(size_t size)
140 struct videobuf_vmalloc_memory *mem;
141 struct videobuf_buffer *vb;
143 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
147 mem = vb->priv = ((char *)vb) + size;
148 mem->magic = MAGIC_VMAL_MEM;
150 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
151 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
152 mem, (long)sizeof(*mem));
157 static int __videobuf_iolock(struct videobuf_queue *q,
158 struct videobuf_buffer *vb,
159 struct v4l2_framebuffer *fbuf)
161 struct videobuf_vmalloc_memory *mem = vb->priv;
166 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
168 switch (vb->memory) {
169 case V4L2_MEMORY_MMAP:
170 dprintk(1, "%s memory method MMAP\n", __func__);
172 /* All handling should be done by __videobuf_mmap_mapper() */
174 printk(KERN_ERR "memory is not alloced/mmapped.\n");
178 case V4L2_MEMORY_USERPTR:
179 pages = PAGE_ALIGN(vb->size);
181 dprintk(1, "%s memory method USERPTR\n", __func__);
184 printk(KERN_ERR "USERPTR is currently not supported\n");
188 /* The only USERPTR currently supported is the one needed for
192 mem->vmalloc = vmalloc_user(pages);
194 printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
197 dprintk(1, "vmalloc is at addr %p (%d pages)\n",
198 mem->vmalloc, pages);
202 /* Kernel userptr is used also by read() method. In this case,
203 there's no need to remap, since data will be copied to user
208 /* FIXME: to properly support USERPTR, remap should occur.
209 The code below won't work, since mem->vma = NULL
211 /* Try to remap memory */
212 rc = remap_vmalloc_range(mem->vma, (void *)vb->baddr, 0);
214 printk(KERN_ERR "mmap: remap failed with error %d", rc);
220 case V4L2_MEMORY_OVERLAY:
222 dprintk(1, "%s memory method OVERLAY/unknown\n", __func__);
224 /* Currently, doesn't support V4L2_MEMORY_OVERLAY */
225 printk(KERN_ERR "Memory method currently unsupported.\n");
232 static int __videobuf_sync(struct videobuf_queue *q,
233 struct videobuf_buffer *buf)
238 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
239 struct vm_area_struct *vma)
241 struct videobuf_vmalloc_memory *mem;
242 struct videobuf_mapping *map;
245 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
247 dprintk(1, "%s\n", __func__);
248 if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED))
251 /* look for first buffer to map */
252 for (first = 0; first < VIDEO_MAX_FRAME; first++) {
253 if (NULL == q->bufs[first])
256 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
258 if (q->bufs[first]->boff == offset)
261 if (VIDEO_MAX_FRAME == first) {
262 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
263 (vma->vm_pgoff << PAGE_SHIFT));
267 /* create mapping + update buffer list */
268 map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
272 q->bufs[first]->map = map;
273 map->start = vma->vm_start;
274 map->end = vma->vm_end;
277 q->bufs[first]->baddr = vma->vm_start;
279 mem = q->bufs[first]->priv;
281 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
283 pages = PAGE_ALIGN(vma->vm_end - vma->vm_start);
284 mem->vmalloc = vmalloc_user(pages);
286 printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
289 dprintk(1, "vmalloc is at addr %p (%d pages)\n", mem->vmalloc, pages);
291 /* Try to remap memory */
292 retval = remap_vmalloc_range(vma, mem->vmalloc, 0);
294 printk(KERN_ERR "mmap: remap failed with error %d. ", retval);
299 vma->vm_ops = &videobuf_vm_ops;
300 vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
301 vma->vm_private_data = map;
303 dprintk(1, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
304 map, q, vma->vm_start, vma->vm_end,
305 (long int) q->bufs[first]->bsize,
306 vma->vm_pgoff, first);
308 videobuf_vm_open(vma);
318 static int __videobuf_copy_to_user(struct videobuf_queue *q,
319 char __user *data, size_t count,
322 struct videobuf_vmalloc_memory *mem = q->read_buf->priv;
324 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
326 BUG_ON(!mem->vmalloc);
328 /* copy to userspace */
329 if (count > q->read_buf->size - q->read_off)
330 count = q->read_buf->size - q->read_off;
332 if (copy_to_user(data, mem->vmalloc+q->read_off, count))
338 static int __videobuf_copy_stream(struct videobuf_queue *q,
339 char __user *data, size_t count, size_t pos,
340 int vbihack, int nonblocking)
343 struct videobuf_vmalloc_memory *mem = q->read_buf->priv;
345 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
348 /* dirty, undocumented hack -- pass the frame counter
349 * within the last four bytes of each vbi data block.
350 * We need that one to maintain backward compatibility
351 * to all vbi decoding software out there ... */
352 fc = (unsigned int *)mem->vmalloc;
353 fc += (q->read_buf->size >> 2) - 1;
354 *fc = q->read_buf->field_count >> 1;
355 dprintk(1, "vbihack: %d\n", *fc);
358 /* copy stuff using the common method */
359 count = __videobuf_copy_to_user(q, data, count, nonblocking);
361 if ((count == -EFAULT) && (0 == pos))
367 static struct videobuf_qtype_ops qops = {
368 .magic = MAGIC_QTYPE_OPS,
370 .alloc = __videobuf_alloc,
371 .iolock = __videobuf_iolock,
372 .sync = __videobuf_sync,
373 .mmap_mapper = __videobuf_mmap_mapper,
374 .video_copy_to_user = __videobuf_copy_to_user,
375 .copy_stream = __videobuf_copy_stream,
376 .vmalloc = videobuf_to_vmalloc,
379 void videobuf_queue_vmalloc_init(struct videobuf_queue *q,
380 const struct videobuf_queue_ops *ops,
383 enum v4l2_buf_type type,
384 enum v4l2_field field,
388 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
391 EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
393 void *videobuf_to_vmalloc(struct videobuf_buffer *buf)
395 struct videobuf_vmalloc_memory *mem = buf->priv;
397 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
401 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
403 void videobuf_vmalloc_free(struct videobuf_buffer *buf)
405 struct videobuf_vmalloc_memory *mem = buf->priv;
407 /* mmapped memory can't be freed here, otherwise mmapped region
408 would be released, while still needed. In this case, the memory
409 release should happen inside videobuf_vm_close().
410 So, it should free memory only if the memory were allocated for
413 if ((buf->memory != V4L2_MEMORY_USERPTR) || buf->baddr)
419 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
426 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);