2 * helper functions for vmalloc video4linux capture buffers
4 * The functions expect the hardware being able to scatter gatter
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) if (unlikely((is) != (should))) \
34 { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }
37 module_param(debug, int, 0644);
39 MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
40 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
41 MODULE_LICENSE("GPL");
43 #define dprintk(level, fmt, arg...) if (debug >= level) \
44 printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg)
47 /***************************************************************************/
50 videobuf_vm_open(struct vm_area_struct *vma)
52 struct videobuf_mapping *map = vma->vm_private_data;
54 dprintk(2,"vm_open %p [count=%u,vma=%08lx-%08lx]\n",map,
55 map->count,vma->vm_start,vma->vm_end);
61 videobuf_vm_close(struct vm_area_struct *vma)
63 struct videobuf_mapping *map = vma->vm_private_data;
64 struct videobuf_queue *q = map->q;
67 dprintk(2,"vm_close %p [count=%u,vma=%08lx-%08lx]\n",map,
68 map->count,vma->vm_start,vma->vm_end);
71 if (0 == map->count) {
72 dprintk(1,"munmap %p q=%p\n",map,q);
73 mutex_lock(&q->vb_lock);
74 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
75 if (NULL == q->bufs[i])
78 if (q->bufs[i]->map != map)
81 q->bufs[i]->map = NULL;
82 q->bufs[i]->baddr = 0;
84 mutex_unlock(&q->vb_lock);
90 static struct vm_operations_struct videobuf_vm_ops =
92 .open = videobuf_vm_open,
93 .close = videobuf_vm_close,
96 /* ---------------------------------------------------------------------
97 * vmalloc handlers for the generic methods
100 /* Allocated area consists on 3 parts:
102 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
103 struct videobuf_dma_sg_memory
106 static void *__videobuf_alloc(size_t size)
108 struct videobuf_vmalloc_memory *mem;
109 struct videobuf_buffer *vb;
111 vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
113 mem = vb->priv = ((char *)vb)+size;
114 mem->magic=MAGIC_VMAL_MEM;
116 dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
117 __func__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
118 mem,(long)sizeof(*mem));
123 static int __videobuf_iolock (struct videobuf_queue* q,
124 struct videobuf_buffer *vb,
125 struct v4l2_framebuffer *fbuf)
128 struct videobuf_vmalloc_memory *mem=vb->priv;
132 MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
134 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
136 /* Currently, doesn't support V4L2_MEMORY_OVERLAY */
137 if ((vb->memory != V4L2_MEMORY_MMAP) &&
138 (vb->memory != V4L2_MEMORY_USERPTR) ) {
139 printk(KERN_ERR "Method currently unsupported.\n");
143 /* FIXME: should be tested with kernel mmap mem */
144 mem->vmalloc=vmalloc_user (PAGE_ALIGN(vb->size));
145 if (NULL == mem->vmalloc) {
146 printk(KERN_ERR "vmalloc (%d pages) failed\n",pages);
150 dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
151 (unsigned long)mem->vmalloc,
152 pages << PAGE_SHIFT);
154 /* It seems that some kernel versions need to do remap *after*
158 int retval=remap_vmalloc_range(mem->vma, mem->vmalloc,0);
162 dprintk(1,"mmap app bug: remap_vmalloc_range area %p error %d\n",
163 mem->vmalloc,retval);
171 static int __videobuf_sync(struct videobuf_queue *q,
172 struct videobuf_buffer *buf)
177 static int __videobuf_mmap_free(struct videobuf_queue *q)
181 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
191 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
192 struct vm_area_struct *vma)
194 struct videobuf_vmalloc_memory *mem;
195 struct videobuf_mapping *map;
198 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
200 if (! (vma->vm_flags & VM_WRITE) || ! (vma->vm_flags & VM_SHARED))
203 /* look for first buffer to map */
204 for (first = 0; first < VIDEO_MAX_FRAME; first++) {
205 if (NULL == q->bufs[first])
208 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
210 if (q->bufs[first]->boff == offset)
213 if (VIDEO_MAX_FRAME == first) {
214 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
215 (vma->vm_pgoff << PAGE_SHIFT));
219 /* create mapping + update buffer list */
220 map = q->bufs[first]->map = kzalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
224 map->start = vma->vm_start;
225 map->end = vma->vm_end;
228 q->bufs[first]->baddr = vma->vm_start;
230 vma->vm_ops = &videobuf_vm_ops;
231 vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
232 vma->vm_private_data = map;
234 mem=q->bufs[first]->priv;
236 MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
238 /* Try to remap memory */
239 retval=remap_vmalloc_range(vma, mem->vmalloc,0);
241 dprintk(1,"mmap: postponing remap_vmalloc_range\n");
243 mem->vma=kmalloc(sizeof(*vma),GFP_KERNEL);
246 q->bufs[first]->map=NULL;
249 memcpy(mem->vma,vma,sizeof(*vma));
252 dprintk(1,"mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
253 map,q,vma->vm_start,vma->vm_end,
254 (long int) q->bufs[first]->bsize,
255 vma->vm_pgoff,first);
257 videobuf_vm_open(vma);
262 static int __videobuf_copy_to_user ( struct videobuf_queue *q,
263 char __user *data, size_t count,
266 struct videobuf_vmalloc_memory *mem=q->read_buf->priv;
268 MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
270 BUG_ON (!mem->vmalloc);
272 /* copy to userspace */
273 if (count > q->read_buf->size - q->read_off)
274 count = q->read_buf->size - q->read_off;
276 if (copy_to_user(data, mem->vmalloc+q->read_off, count))
282 static int __videobuf_copy_stream ( struct videobuf_queue *q,
283 char __user *data, size_t count, size_t pos,
284 int vbihack, int nonblocking )
287 struct videobuf_vmalloc_memory *mem=q->read_buf->priv;
289 MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
292 /* dirty, undocumented hack -- pass the frame counter
293 * within the last four bytes of each vbi data block.
294 * We need that one to maintain backward compatibility
295 * to all vbi decoding software out there ... */
296 fc = (unsigned int*)mem->vmalloc;
297 fc += (q->read_buf->size>>2) -1;
298 *fc = q->read_buf->field_count >> 1;
299 dprintk(1,"vbihack: %d\n",*fc);
302 /* copy stuff using the common method */
303 count = __videobuf_copy_to_user (q,data,count,nonblocking);
305 if ( (count==-EFAULT) && (0 == pos) )
311 static struct videobuf_qtype_ops qops = {
312 .magic = MAGIC_QTYPE_OPS,
314 .alloc = __videobuf_alloc,
315 .iolock = __videobuf_iolock,
316 .sync = __videobuf_sync,
317 .mmap_free = __videobuf_mmap_free,
318 .mmap_mapper = __videobuf_mmap_mapper,
319 .video_copy_to_user = __videobuf_copy_to_user,
320 .copy_stream = __videobuf_copy_stream,
323 void videobuf_queue_vmalloc_init(struct videobuf_queue* q,
324 struct videobuf_queue_ops *ops,
327 enum v4l2_buf_type type,
328 enum v4l2_field field,
332 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
336 EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
338 void *videobuf_to_vmalloc (struct videobuf_buffer *buf)
340 struct videobuf_vmalloc_memory *mem=buf->priv;
342 MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
346 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
348 void videobuf_vmalloc_free (struct videobuf_buffer *buf)
350 struct videobuf_vmalloc_memory *mem=buf->priv;
353 MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
360 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);