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
  88                         q->ops->buf_release(q,q->bufs[i]);
  89
  90                         mem->map   = NULL;
  91                         q->bufs[i]->baddr = 0;
  92                 }
  93                 mutex_unlock(&q->lock);
  94                 kfree(map);
  95         }
  96         return;
  97 }
  98
  99 static struct vm_operations_struct videobuf_vm_ops =
 100 {
 101         .open     = videobuf_vm_open,
 102         .close    = videobuf_vm_close,
 103 };
 104
 105 /* ---------------------------------------------------------------------
 106  * vmalloc handlers for the generic methods
 107  */
 108
 109 /* Allocated area consists on 3 parts:
 110         struct video_buffer
 111         struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 112         struct videobuf_pci_sg_memory
 113  */
 114
 115 static void *__videobuf_alloc(size_t size)
 116 {
 117         struct videbuf_vmalloc_memory *mem;
 118         struct videobuf_buffer *vb;
 119
 120         vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
 121
 122         mem = vb->priv = ((char *)vb)+size;
 123         mem->magic=MAGIC_VMAL_MEM;
 124
 125         dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 126                 __FUNCTION__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
 127                 mem,(long)sizeof(*mem));
 128
 129         return vb;
 130 }
 131
 132 static int __videobuf_iolock (struct videobuf_queue* q,
 133                               struct videobuf_buffer *vb,
 134                               struct v4l2_framebuffer *fbuf)
 135 {
 136         int pages;
 137
 138         struct videbuf_vmalloc_memory *mem=vb->priv;
 139
 140
 141         BUG_ON(!mem);
 142
 143         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 144
 145         pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
 146
 147         /* Currently, doesn't support V4L2_MEMORY_OVERLAY */
 148         if ((vb->memory != V4L2_MEMORY_MMAP) &&
 149                                 (vb->memory != V4L2_MEMORY_USERPTR) ) {
 150                 printk(KERN_ERR "Method currently unsupported.\n");
 151                 return -EINVAL;
 152         }
 153
 154         /* FIXME: should be tested with kernel mmap mem */
 155         mem->vmalloc=vmalloc_user (PAGE_ALIGN(vb->size));
 156         if (NULL == mem->vmalloc) {
 157                 printk(KERN_ERR "vmalloc (%d pages) failed\n",pages);
 158                 return -ENOMEM;
 159         }
 160
 161         dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
 162                                 (unsigned long)mem->vmalloc,
 163                                 pages << PAGE_SHIFT);
 164
 165         /* It seems that some kernel versions need to do remap *after*
 166            the mmap() call
 167          */
 168         if (mem->vma) {
 169                 int retval=remap_vmalloc_range(mem->vma, mem->vmalloc,0);
 170                 kfree(mem->vma);
 171                 mem->vma=NULL;
 172                 if (retval<0) {
 173                         dprintk(1,"mmap app bug: remap_vmalloc_range area %p error %d\n",
 174                                 mem->vmalloc,retval);
 175                         return retval;
 176                 }
 177         }
 178
 179         return 0;
 180 }
 181
 182 static int __videobuf_sync(struct videobuf_queue *q,
 183                            struct videobuf_buffer *buf)
 184 {
 185         return 0;
 186 }
 187
 188 static int __videobuf_mmap_free(struct videobuf_queue *q)
 189 {
 190         unsigned int i;
 191
 192         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 193                 if (q->bufs[i]) {
 194                         struct videbuf_vmalloc_memory *mem=q->bufs[i]->priv;
 195                         if (mem && mem->map)
 196                                 return -EBUSY;
 197                 }
 198         }
 199
 200         return 0;
 201 }
 202
 203 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 204                          struct vm_area_struct *vma)
 205 {
 206         struct videbuf_vmalloc_memory *mem;
 207         struct videobuf_mapping *map;
 208         unsigned int first;
 209         int retval;
 210         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 211
 212         if (! (vma->vm_flags & VM_WRITE) || ! (vma->vm_flags & VM_SHARED))
 213                 return -EINVAL;
 214
 215         /* look for first buffer to map */
 216         for (first = 0; first < VIDEO_MAX_FRAME; first++) {
 217                 if (NULL == q->bufs[first])
 218                         continue;
 219
 220                 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
 221                         continue;
 222                 if (q->bufs[first]->boff == offset)
 223                         break;
 224         }
 225         if (VIDEO_MAX_FRAME == first) {
 226                 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
 227                         (vma->vm_pgoff << PAGE_SHIFT));
 228                 return -EINVAL;
 229         }
 230         mem=q->bufs[first]->priv;
 231         BUG_ON (!mem);
 232         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 233
 234         /* create mapping + update buffer list */
 235         map = mem->map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
 236         if (NULL == map)
 237                 return -ENOMEM;
 238
 239         map->start = vma->vm_start;
 240         map->end   = vma->vm_end;
 241         map->q     = q;
 242
 243         q->bufs[first]->baddr = vma->vm_start;
 244
 245         vma->vm_ops          = &videobuf_vm_ops;
 246         vma->vm_flags       |= VM_DONTEXPAND | VM_RESERVED;
 247         vma->vm_private_data = map;
 248
 249         /* Try to remap memory */
 250         retval=remap_vmalloc_range(vma, mem->vmalloc,0);
 251         if (retval<0) {
 252                 dprintk(1,"mmap: postponing remap_vmalloc_range\n");
 253                 mem->vma=kmalloc(sizeof(*vma),GFP_KERNEL);
 254                 if (!mem->vma) {
 255                         kfree(map);
 256                         mem->map=NULL;
 257                         return -ENOMEM;
 258                 }
 259                 memcpy(mem->vma,vma,sizeof(*vma));
 260         }
 261
 262         dprintk(1,"mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
 263                 map,q,vma->vm_start,vma->vm_end,
 264                 (long int) q->bufs[first]->bsize,
 265                 vma->vm_pgoff,first);
 266
 267         videobuf_vm_open(vma);
 268
 269         return (0);
 270 }
 271
 272 static int __videobuf_is_mmapped (struct videobuf_buffer *buf)
 273 {
 274         struct videbuf_vmalloc_memory *mem=buf->priv;
 275         BUG_ON (!mem);
 276         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 277
 278         return (mem->map)?1:0;
 279 }
 280
 281 static int __videobuf_copy_to_user ( struct videobuf_queue *q,
 282                                 char __user *data, size_t count,
 283                                 int nonblocking )
 284 {
 285         struct videbuf_vmalloc_memory *mem=q->read_buf->priv;
 286         BUG_ON (!mem);
 287         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 288
 289         BUG_ON (!mem->vmalloc);
 290
 291         /* copy to userspace */
 292         if (count > q->read_buf->size - q->read_off)
 293                 count = q->read_buf->size - q->read_off;
 294
 295         if (copy_to_user(data, mem->vmalloc+q->read_off, count))
 296                 return -EFAULT;
 297
 298         return count;
 299 }
 300
 301 static int __videobuf_copy_stream ( struct videobuf_queue *q,
 302                                 char __user *data, size_t count, size_t pos,
 303                                 int vbihack, int nonblocking )
 304 {
 305         unsigned int  *fc;
 306         struct videbuf_vmalloc_memory *mem=q->read_buf->priv;
 307         BUG_ON (!mem);
 308         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 309
 310         if (vbihack) {
 311                 /* dirty, undocumented hack -- pass the frame counter
 312                         * within the last four bytes of each vbi data block.
 313                         * We need that one to maintain backward compatibility
 314                         * to all vbi decoding software out there ... */
 315                 fc  = (unsigned int*)mem->vmalloc;
 316                 fc += (q->read_buf->size>>2) -1;
 317                 *fc = q->read_buf->field_count >> 1;
 318                 dprintk(1,"vbihack: %d\n",*fc);
 319         }
 320
 321         /* copy stuff using the common method */
 322         count = __videobuf_copy_to_user (q,data,count,nonblocking);
 323
 324         if ( (count==-EFAULT) && (0 == pos) )
 325                 return -EFAULT;
 326
 327         return count;
 328 }
 329
 330 static struct videobuf_qtype_ops qops = {
 331         .magic        = MAGIC_QTYPE_OPS,
 332
 333         .alloc        = __videobuf_alloc,
 334         .iolock       = __videobuf_iolock,
 335         .sync         = __videobuf_sync,
 336         .mmap_free    = __videobuf_mmap_free,
 337         .mmap_mapper  = __videobuf_mmap_mapper,
 338         .is_mmapped   = __videobuf_is_mmapped,
 339         .copy_to_user = __videobuf_copy_to_user,
 340         .copy_stream  = __videobuf_copy_stream,
 341 };
 342
 343 void videobuf_queue_vmalloc_init(struct videobuf_queue* q,
 344                          struct videobuf_queue_ops *ops,
 345                          void *dev,
 346                          spinlock_t *irqlock,
 347                          enum v4l2_buf_type type,
 348                          enum v4l2_field field,
 349                          unsigned int msize,
 350                          void *priv)
 351 {
 352         videobuf_queue_init(q, ops, dev, irqlock, type, field, msize, priv);
 353         q->int_ops=&qops;
 354 }
 355
 356 EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
 357
 358 void *videobuf_to_vmalloc (struct videobuf_buffer *buf)
 359 {
 360         struct videbuf_vmalloc_memory *mem=buf->priv;
 361         BUG_ON (!mem);
 362         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 363
 364         return mem->vmalloc;
 365 }
 366 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
 367
 368 void videobuf_vmalloc_free (struct videobuf_buffer *buf)
 369 {
 370         struct videbuf_vmalloc_memory *mem=buf->priv;
 371         BUG_ON (!mem);
 372
 373         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 374
 375         vfree(mem->vmalloc);
 376         mem->vmalloc=NULL;
 377
 378         return;
 379 }
 380 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);
 381
 382 /*
 383  * Local variables:
 384  * c-basic-offset: 8
 385  * End:
 386  */