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