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