drivers/media/video/videobuf-vmalloc.c

   1 /*
   2  * helper functions for vmalloc video4linux capture buffers
   3  *
   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.
   8  *
   9  * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
  10  *
  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
  14  */
  15
  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>
  21
  22 #include <linux/pci.h>
  23 #include <linux/vmalloc.h>
  24 #include <linux/pagemap.h>
  25 #include <asm/page.h>
  26 #include <asm/pgtable.h>
  27
  28 #include <media/videobuf-vmalloc.h>
  29
  30 #define MAGIC_DMABUF   0x17760309
  31 #define MAGIC_VMAL_MEM 0x18221223
  32
  33 #define MAGIC_CHECK(is,should)  if (unlikely((is) != (should))) \
  34         { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }
  35
  36 static int debug = 0;
  37 module_param(debug, int, 0644);
  38
  39 MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
  40 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
  41 MODULE_LICENSE("GPL");
  42
  43 #define dprintk(level, fmt, arg...)     if (debug >= level) \
  44         printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
  45
  46
  47 /***************************************************************************/
  48
  49 static void
  50 videobuf_vm_open(struct vm_area_struct *vma)
  51 {
  52         struct videobuf_mapping *map = vma->vm_private_data;
  53
  54         dprintk(2,"vm_open %p [count=%d,vma=%08lx-%08lx]\n",map,
  55                 map->count,vma->vm_start,vma->vm_end);
  56
  57         map->count++;
  58 }
  59
  60 static void
  61 videobuf_vm_close(struct vm_area_struct *vma)
  62 {
  63         struct videobuf_mapping *map = vma->vm_private_data;
  64         struct videobuf_queue *q = map->q;
  65         struct videbuf_vmalloc_memory *mem;
  66         int i;
  67
  68         dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map,
  69                 map->count,vma->vm_start,vma->vm_end);
  70
  71         map->count--;
  72         if (0 == map->count) {
  73                 dprintk(1,"munmap %p q=%p\n",map,q);
  74                 mutex_lock(&q->lock);
  75                 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
  76                         if (NULL == q->bufs[i])
  77                                 continue;
  78                         mem=q->bufs[i]->priv;
  79
  80                         if (!mem)
  81                                 continue;
  82
  83                         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
  84
  85                         if (mem->map != map)
  86                                 continue;
  87                         mem->map   = NULL;
  88                         q->bufs[i]->baddr = 0;
  89                         q->ops->buf_release(q,q->bufs[i]);
  90                 }
  91                 mutex_unlock(&q->lock);
  92                 kfree(map);
  93         }
  94         return;
  95 }
  96
  97 static struct vm_operations_struct videobuf_vm_ops =
  98 {
  99         .open     = videobuf_vm_open,
 100         .close    = videobuf_vm_close,
 101 };
 102
 103 /* ---------------------------------------------------------------------
 104  * vmalloc handlers for the generic methods
 105  */
 106
 107 /* Allocated area consists on 3 parts:
 108         struct video_buffer
 109         struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 110         struct videobuf_pci_sg_memory
 111  */
 112
 113 static void *__videobuf_alloc(size_t size)
 114 {
 115         struct videbuf_vmalloc_memory *mem;
 116         struct videobuf_buffer *vb;
 117
 118         vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
 119
 120         mem = vb->priv = ((char *)vb)+size;
 121         mem->magic=MAGIC_VMAL_MEM;
 122
 123         dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 124                 __FUNCTION__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
 125                 mem,(long)sizeof(*mem));
 126
 127         return vb;
 128 }
 129
 130 static int __videobuf_iolock (struct videobuf_queue* q,
 131                               struct videobuf_buffer *vb,
 132                               struct v4l2_framebuffer *fbuf)
 133 {
 134         int pages;
 135
 136         struct videbuf_vmalloc_memory *mem=vb->priv;
 137
 138
 139         BUG_ON(!mem);
 140
 141         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 142
 143
 144         pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
 145
 146         /* Currently, doesn't support V4L2_MEMORY_OVERLAY */
 147         if ((vb->memory != V4L2_MEMORY_MMAP) &&
 148                                 (vb->memory != V4L2_MEMORY_USERPTR) ) {
 149                 printk(KERN_ERR "Method currently unsupported.\n");
 150                 return -EINVAL;
 151         }
 152
 153         /* FIXME: should be tested with kernel mmap mem */
 154         mem->vmalloc=vmalloc_user (PAGE_ALIGN(vb->size));
 155         if (NULL == mem->vmalloc) {
 156                 dprintk(1,"vmalloc (%d pages) failed\n",pages);
 157                 return -ENOMEM;
 158         }
 159
 160         dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
 161                                 (unsigned long)mem->vmalloc,
 162                                 pages << PAGE_SHIFT);
 163
 164         /* It seems that some kernel versions need to do remap *after*
 165            the mmap() call
 166          */
 167         if (mem->vma) {
 168                 int retval=remap_vmalloc_range(mem->vma, mem->vmalloc,0);
 169                 kfree(mem->vma);
 170                 mem->vma=NULL;
 171                 if (retval<0) {
 172                         dprintk(1,"mmap app bug: remap_vmalloc_range area %p error %d\n",
 173                                 mem->vmalloc,retval);
 174                         return retval;
 175                 }
 176         }
 177
 178         return 0;
 179 }
 180
 181 static int __videobuf_sync(struct videobuf_queue *q,
 182                            struct videobuf_buffer *buf)
 183 {
 184         return 0;
 185 }
 186
 187 static int __videobuf_mmap_free(struct videobuf_queue *q)
 188 {
 189         unsigned int i;
 190
 191         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 192                 if (q->bufs[i]) {
 193                         struct videbuf_vmalloc_memory *mem=q->bufs[i]->priv;
 194                         if (mem && mem->map)
 195                                 return -EBUSY;
 196                 }
 197         }
 198
 199         return 0;
 200 }
 201
 202 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 203                          struct vm_area_struct *vma)
 204 {
 205         struct videbuf_vmalloc_memory *mem;
 206         struct videobuf_mapping *map;
 207         unsigned int first;
 208         int retval;
 209         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 210
 211         if (! (vma->vm_flags & VM_WRITE) || ! (vma->vm_flags & VM_SHARED))
 212                 return -EINVAL;
 213
 214         /* look for first buffer to map */
 215         for (first = 0; first < VIDEO_MAX_FRAME; first++) {
 216                 if (NULL == q->bufs[first])
 217                         continue;
 218
 219                 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
 220                         continue;
 221                 if (q->bufs[first]->boff == offset)
 222                         break;
 223         }
 224         if (VIDEO_MAX_FRAME == first) {
 225                 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
 226                         (vma->vm_pgoff << PAGE_SHIFT));
 227                 return -EINVAL;
 228         }
 229         mem=q->bufs[first]->priv;
 230         BUG_ON (!mem);
 231         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 232
 233         /* create mapping + update buffer list */
 234         map = mem->map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
 235         if (NULL == map)
 236                 return -ENOMEM;
 237
 238         map->start = vma->vm_start;
 239         map->end   = vma->vm_end;
 240         map->q     = q;
 241
 242         q->bufs[first]->baddr = vma->vm_start;
 243
 244         vma->vm_ops          = &videobuf_vm_ops;
 245         vma->vm_flags       |= VM_DONTEXPAND | VM_RESERVED;
 246         vma->vm_private_data = map;
 247
 248         /* Try to remap memory */
 249         retval=remap_vmalloc_range(vma, mem->vmalloc,0);
 250         if (retval<0) {
 251                 dprintk(1,"mmap: postponing remap_vmalloc_range\n");
 252                 mem->vma=kmalloc(sizeof(*vma),GFP_KERNEL);
 253                 if (!mem->vma) {
 254                         kfree(map);
 255                         mem->map=NULL;
 256                         return -ENOMEM;
 257                 }
 258                 memcpy(mem->vma,vma,sizeof(*vma));
 259         }
 260
 261         dprintk(1,"mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
 262                 map,q,vma->vm_start,vma->vm_end,
 263                 (long int) q->bufs[first]->bsize,
 264                 vma->vm_pgoff,first);
 265
 266         videobuf_vm_open(vma);
 267
 268         return (0);
 269 }
 270
 271 static int __videobuf_is_mmapped (struct videobuf_buffer *buf)
 272 {
 273         struct videbuf_vmalloc_memory *mem=buf->priv;
 274         BUG_ON (!mem);
 275         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 276
 277         return (mem->map)?1:0;
 278 }
 279
 280 static int __videobuf_copy_to_user ( struct videobuf_queue *q,
 281                                 char __user *data, size_t count,
 282                                 int nonblocking )
 283 {
 284         struct videbuf_vmalloc_memory *mem=q->read_buf->priv;
 285         BUG_ON (!mem);
 286         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 287
 288         BUG_ON (!mem->vmalloc);
 289
 290         /* copy to userspace */
 291         if (count > q->read_buf->size - q->read_off)
 292                 count = q->read_buf->size - q->read_off;
 293
 294         if (copy_to_user(data, mem->vmalloc+q->read_off, count))
 295                 return -EFAULT;
 296
 297         return count;
 298 }
 299
 300 static int __videobuf_copy_stream ( struct videobuf_queue *q,
 301                                 char __user *data, size_t count, size_t pos,
 302                                 int vbihack, int nonblocking )
 303 {
 304         unsigned int  *fc;
 305         struct videbuf_vmalloc_memory *mem=q->read_buf->priv;
 306         BUG_ON (!mem);
 307         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 308
 309         if (vbihack) {
 310                 /* dirty, undocumented hack -- pass the frame counter
 311                         * within the last four bytes of each vbi data block.
 312                         * We need that one to maintain backward compatibility
 313                         * to all vbi decoding software out there ... */
 314                 fc  = (unsigned int*)mem->vmalloc;
 315                 fc += (q->read_buf->size>>2) -1;
 316                 *fc = q->read_buf->field_count >> 1;
 317                 dprintk(1,"vbihack: %d\n",*fc);
 318         }
 319
 320         /* copy stuff using the common method */
 321         count = __videobuf_copy_to_user (q,data,count,nonblocking);
 322
 323         if ( (count==-EFAULT) && (0 == pos) )
 324                 return -EFAULT;
 325
 326         return count;
 327 }
 328
 329 static struct videobuf_qtype_ops qops = {
 330         .magic        = MAGIC_QTYPE_OPS,
 331
 332         .alloc        = __videobuf_alloc,
 333         .iolock       = __videobuf_iolock,
 334         .sync         = __videobuf_sync,
 335         .mmap_free    = __videobuf_mmap_free,
 336         .mmap_mapper  = __videobuf_mmap_mapper,
 337         .is_mmapped   = __videobuf_is_mmapped,
 338         .copy_to_user = __videobuf_copy_to_user,
 339         .copy_stream  = __videobuf_copy_stream,
 340 };
 341
 342 void videobuf_queue_vmalloc_init(struct videobuf_queue* q,
 343                          struct videobuf_queue_ops *ops,
 344                          void *dev,
 345                          spinlock_t *irqlock,
 346                          enum v4l2_buf_type type,
 347                          enum v4l2_field field,
 348                          unsigned int msize,
 349                          void *priv)
 350 {
 351         videobuf_queue_init(q, ops, dev, irqlock, type, field, msize, priv);
 352         q->int_ops=&qops;
 353 }
 354
 355 EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
 356
 357 void *videobuf_to_vmalloc (struct videobuf_buffer *buf)
 358 {
 359         struct videbuf_vmalloc_memory *mem=buf->priv;
 360         BUG_ON (!mem);
 361         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 362
 363         return mem->vmalloc;
 364 }
 365 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
 366
 367 void videobuf_vmalloc_free (struct videobuf_buffer *buf)
 368 {
 369         struct videbuf_vmalloc_memory *mem=buf->priv;
 370         BUG_ON (!mem);
 371
 372         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 373
 374         vfree(mem->vmalloc);
 375         mem->vmalloc=NULL;
 376
 377         return;
 378 }
 379 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);
 380
 381 /*
 382  * Local variables:
 383  * c-basic-offset: 8
 384  * End:
 385  */