SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/media/video/videobuf-dma-contig.c

   1 /*
   2  * helper functions for physically contiguous capture buffers
   3  *
   4  * The functions support hardware lacking scatter gather support
   5  * (i.e. the buffers must be linear in physical memory)
   6  *
   7  * Copyright (c) 2008 Magnus Damm
   8  *
   9  * Based on videobuf-vmalloc.c,
  10  * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2
  15  */
  16
  17 #include <linux/init.h>
  18 #include <linux/module.h>
  19 #include <linux/mm.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/dma-mapping.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <media/videobuf-dma-contig.h>
  25
  26 struct videobuf_dma_contig_memory {
  27         u32 magic;
  28         void *vaddr;
  29         dma_addr_t dma_handle;
  30         unsigned long size;
  31         int is_userptr;
  32 };
  33
  34 #define MAGIC_DC_MEM 0x0733ac61
  35 #define MAGIC_CHECK(is, should)                                             \
  36         if (unlikely((is) != (should))) {                                   \
  37                 pr_err("magic mismatch: %x expected %x\n", (is), (should)); \
  38                 BUG();                                                      \
  39         }
  40
  41 static void
  42 videobuf_vm_open(struct vm_area_struct *vma)
  43 {
  44         struct videobuf_mapping *map = vma->vm_private_data;
  45
  46         dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n",
  47                 map, map->count, vma->vm_start, vma->vm_end);
  48
  49         map->count++;
  50 }
  51
  52 static void videobuf_vm_close(struct vm_area_struct *vma)
  53 {
  54         struct videobuf_mapping *map = vma->vm_private_data;
  55         struct videobuf_queue *q = map->q;
  56         int i;
  57
  58         dev_dbg(map->q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n",
  59                 map, map->count, vma->vm_start, vma->vm_end);
  60
  61         map->count--;
  62         if (0 == map->count) {
  63                 struct videobuf_dma_contig_memory *mem;
  64
  65                 dev_dbg(map->q->dev, "munmap %p q=%p\n", map, q);
  66                 mutex_lock(&q->vb_lock);
  67
  68                 /* We need first to cancel streams, before unmapping */
  69                 if (q->streaming)
  70                         videobuf_queue_cancel(q);
  71
  72                 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
  73                         if (NULL == q->bufs[i])
  74                                 continue;
  75
  76                         if (q->bufs[i]->map != map)
  77                                 continue;
  78
  79                         mem = q->bufs[i]->priv;
  80                         if (mem) {
  81                                 /* This callback is called only if kernel has
  82                                    allocated memory and this memory is mmapped.
  83                                    In this case, memory should be freed,
  84                                    in order to do memory unmap.
  85                                  */
  86
  87                                 MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
  88
  89                                 /* vfree is not atomic - can't be
  90                                    called with IRQ's disabled
  91                                  */
  92                                 dev_dbg(map->q->dev, "buf[%d] freeing %p\n",
  93                                         i, mem->vaddr);
  94
  95                                 dma_free_coherent(q->dev, mem->size,
  96                                                   mem->vaddr, mem->dma_handle);
  97                                 mem->vaddr = NULL;
  98                         }
  99
 100                         q->bufs[i]->map   = NULL;
 101                         q->bufs[i]->baddr = 0;
 102                 }
 103
 104                 kfree(map);
 105
 106                 mutex_unlock(&q->vb_lock);
 107         }
 108 }
 109
 110 static const struct vm_operations_struct videobuf_vm_ops = {
 111         .open     = videobuf_vm_open,
 112         .close    = videobuf_vm_close,
 113 };
 114
 115 /**
 116  * videobuf_dma_contig_user_put() - reset pointer to user space buffer
 117  * @mem: per-buffer private videobuf-dma-contig data
 118  *
 119  * This function resets the user space pointer
 120  */
 121 static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
 122 {
 123         mem->is_userptr = 0;
 124         mem->dma_handle = 0;
 125         mem->size = 0;
 126 }
 127
 128 /**
 129  * videobuf_dma_contig_user_get() - setup user space memory pointer
 130  * @mem: per-buffer private videobuf-dma-contig data
 131  * @vb: video buffer to map
 132  *
 133  * This function validates and sets up a pointer to user space memory.
 134  * Only physically contiguous pfn-mapped memory is accepted.
 135  *
 136  * Returns 0 if successful.
 137  */
 138 static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
 139                                         struct videobuf_buffer *vb)
 140 {
 141         struct mm_struct *mm = current->mm;
 142         struct vm_area_struct *vma;
 143         unsigned long prev_pfn, this_pfn;
 144         unsigned long pages_done, user_address;
 145         unsigned int offset;
 146         int ret;
 147
 148         offset = vb->baddr & ~PAGE_MASK;
 149         mem->size = PAGE_ALIGN(vb->size + offset);
 150         mem->is_userptr = 0;
 151         ret = -EINVAL;
 152
 153         down_read(&mm->mmap_sem);
 154
 155         vma = find_vma(mm, vb->baddr);
 156         if (!vma)
 157                 goto out_up;
 158
 159         if ((vb->baddr + mem->size) > vma->vm_end)
 160                 goto out_up;
 161
 162         pages_done = 0;
 163         prev_pfn = 0; /* kill warning */
 164         user_address = vb->baddr;
 165
 166         while (pages_done < (mem->size >> PAGE_SHIFT)) {
 167                 ret = follow_pfn(vma, user_address, &this_pfn);
 168                 if (ret)
 169                         break;
 170
 171                 if (pages_done == 0)
 172                         mem->dma_handle = (this_pfn << PAGE_SHIFT) + offset;
 173                 else if (this_pfn != (prev_pfn + 1))
 174                         ret = -EFAULT;
 175
 176                 if (ret)
 177                         break;
 178
 179                 prev_pfn = this_pfn;
 180                 user_address += PAGE_SIZE;
 181                 pages_done++;
 182         }
 183
 184         if (!ret)
 185                 mem->is_userptr = 1;
 186
 187  out_up:
 188         up_read(&current->mm->mmap_sem);
 189
 190         return ret;
 191 }
 192
 193 static void *__videobuf_alloc(size_t size)
 194 {
 195         struct videobuf_dma_contig_memory *mem;
 196         struct videobuf_buffer *vb;
 197
 198         vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
 199         if (vb) {
 200                 mem = vb->priv = ((char *)vb) + size;
 201                 mem->magic = MAGIC_DC_MEM;
 202         }
 203
 204         return vb;
 205 }
 206
 207 static void *__videobuf_to_vmalloc(struct videobuf_buffer *buf)
 208 {
 209         struct videobuf_dma_contig_memory *mem = buf->priv;
 210
 211         BUG_ON(!mem);
 212         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 213
 214         return mem->vaddr;
 215 }
 216
 217 static int __videobuf_iolock(struct videobuf_queue *q,
 218                              struct videobuf_buffer *vb,
 219                              struct v4l2_framebuffer *fbuf)
 220 {
 221         struct videobuf_dma_contig_memory *mem = vb->priv;
 222
 223         BUG_ON(!mem);
 224         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 225
 226         switch (vb->memory) {
 227         case V4L2_MEMORY_MMAP:
 228                 dev_dbg(q->dev, "%s memory method MMAP\n", __func__);
 229
 230                 /* All handling should be done by __videobuf_mmap_mapper() */
 231                 if (!mem->vaddr) {
 232                         dev_err(q->dev, "memory is not alloced/mmapped.\n");
 233                         return -EINVAL;
 234                 }
 235                 break;
 236         case V4L2_MEMORY_USERPTR:
 237                 dev_dbg(q->dev, "%s memory method USERPTR\n", __func__);
 238
 239                 /* handle pointer from user space */
 240                 if (vb->baddr)
 241                         return videobuf_dma_contig_user_get(mem, vb);
 242
 243                 /* allocate memory for the read() method */
 244                 mem->size = PAGE_ALIGN(vb->size);
 245                 mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
 246                                                 &mem->dma_handle, GFP_KERNEL);
 247                 if (!mem->vaddr) {
 248                         dev_err(q->dev, "dma_alloc_coherent %ld failed\n",
 249                                          mem->size);
 250                         return -ENOMEM;
 251                 }
 252
 253                 dev_dbg(q->dev, "dma_alloc_coherent data is at %p (%ld)\n",
 254                         mem->vaddr, mem->size);
 255                 break;
 256         case V4L2_MEMORY_OVERLAY:
 257         default:
 258                 dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n",
 259                         __func__);
 260                 return -EINVAL;
 261         }
 262
 263         return 0;
 264 }
 265
 266 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 267                                   struct vm_area_struct *vma)
 268 {
 269         struct videobuf_dma_contig_memory *mem;
 270         struct videobuf_mapping *map;
 271         unsigned int first;
 272         int retval;
 273         unsigned long size, offset = vma->vm_pgoff << PAGE_SHIFT;
 274
 275         dev_dbg(q->dev, "%s\n", __func__);
 276         if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED))
 277                 return -EINVAL;
 278
 279         /* look for first buffer to map */
 280         for (first = 0; first < VIDEO_MAX_FRAME; first++) {
 281                 if (!q->bufs[first])
 282                         continue;
 283
 284                 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
 285                         continue;
 286                 if (q->bufs[first]->boff == offset)
 287                         break;
 288         }
 289         if (VIDEO_MAX_FRAME == first) {
 290                 dev_dbg(q->dev, "invalid user space offset [offset=0x%lx]\n",
 291                         offset);
 292                 return -EINVAL;
 293         }
 294
 295         /* create mapping + update buffer list */
 296         map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
 297         if (!map)
 298                 return -ENOMEM;
 299
 300         q->bufs[first]->map = map;
 301         map->start = vma->vm_start;
 302         map->end = vma->vm_end;
 303         map->q = q;
 304
 305         q->bufs[first]->baddr = vma->vm_start;
 306
 307         mem = q->bufs[first]->priv;
 308         BUG_ON(!mem);
 309         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 310
 311         mem->size = PAGE_ALIGN(q->bufs[first]->bsize);
 312         mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
 313                                         &mem->dma_handle, GFP_KERNEL);
 314         if (!mem->vaddr) {
 315                 dev_err(q->dev, "dma_alloc_coherent size %ld failed\n",
 316                         mem->size);
 317                 goto error;
 318         }
 319         dev_dbg(q->dev, "dma_alloc_coherent data is at addr %p (size %ld)\n",
 320                 mem->vaddr, mem->size);
 321
 322         /* Try to remap memory */
 323
 324         size = vma->vm_end - vma->vm_start;
 325         size = (size < mem->size) ? size : mem->size;
 326
 327         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 328         retval = remap_pfn_range(vma, vma->vm_start,
 329                                  mem->dma_handle >> PAGE_SHIFT,
 330                                  size, vma->vm_page_prot);
 331         if (retval) {
 332                 dev_err(q->dev, "mmap: remap failed with error %d. ", retval);
 333                 dma_free_coherent(q->dev, mem->size,
 334                                   mem->vaddr, mem->dma_handle);
 335                 goto error;
 336         }
 337
 338         vma->vm_ops          = &videobuf_vm_ops;
 339         vma->vm_flags       |= VM_DONTEXPAND;
 340         vma->vm_private_data = map;
 341
 342         dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
 343                 map, q, vma->vm_start, vma->vm_end,
 344                 (long int) q->bufs[first]->bsize,
 345                 vma->vm_pgoff, first);
 346
 347         videobuf_vm_open(vma);
 348
 349         return 0;
 350
 351 error:
 352         kfree(map);
 353         return -ENOMEM;
 354 }
 355
 356 static int __videobuf_copy_to_user(struct videobuf_queue *q,
 357                                    char __user *data, size_t count,
 358                                    int nonblocking)
 359 {
 360         struct videobuf_dma_contig_memory *mem = q->read_buf->priv;
 361         void *vaddr;
 362
 363         BUG_ON(!mem);
 364         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 365         BUG_ON(!mem->vaddr);
 366
 367         /* copy to userspace */
 368         if (count > q->read_buf->size - q->read_off)
 369                 count = q->read_buf->size - q->read_off;
 370
 371         vaddr = mem->vaddr;
 372
 373         if (copy_to_user(data, vaddr + q->read_off, count))
 374                 return -EFAULT;
 375
 376         return count;
 377 }
 378
 379 static int __videobuf_copy_stream(struct videobuf_queue *q,
 380                                   char __user *data, size_t count, size_t pos,
 381                                   int vbihack, int nonblocking)
 382 {
 383         unsigned int  *fc;
 384         struct videobuf_dma_contig_memory *mem = q->read_buf->priv;
 385
 386         BUG_ON(!mem);
 387         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 388
 389         if (vbihack) {
 390                 /* dirty, undocumented hack -- pass the frame counter
 391                         * within the last four bytes of each vbi data block.
 392                         * We need that one to maintain backward compatibility
 393                         * to all vbi decoding software out there ... */
 394                 fc = (unsigned int *)mem->vaddr;
 395                 fc += (q->read_buf->size >> 2) - 1;
 396                 *fc = q->read_buf->field_count >> 1;
 397                 dev_dbg(q->dev, "vbihack: %d\n", *fc);
 398         }
 399
 400         /* copy stuff using the common method */
 401         count = __videobuf_copy_to_user(q, data, count, nonblocking);
 402
 403         if ((count == -EFAULT) && (pos == 0))
 404                 return -EFAULT;
 405
 406         return count;
 407 }
 408
 409 static struct videobuf_qtype_ops qops = {
 410         .magic        = MAGIC_QTYPE_OPS,
 411
 412         .alloc        = __videobuf_alloc,
 413         .iolock       = __videobuf_iolock,
 414         .mmap_mapper  = __videobuf_mmap_mapper,
 415         .video_copy_to_user = __videobuf_copy_to_user,
 416         .copy_stream  = __videobuf_copy_stream,
 417         .vmalloc      = __videobuf_to_vmalloc,
 418 };
 419
 420 void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
 421                                     const struct videobuf_queue_ops *ops,
 422                                     struct device *dev,
 423                                     spinlock_t *irqlock,
 424                                     enum v4l2_buf_type type,
 425                                     enum v4l2_field field,
 426                                     unsigned int msize,
 427                                     void *priv)
 428 {
 429         videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
 430                                  priv, &qops);
 431 }
 432 EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init);
 433
 434 dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
 435 {
 436         struct videobuf_dma_contig_memory *mem = buf->priv;
 437
 438         BUG_ON(!mem);
 439         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 440
 441         return mem->dma_handle;
 442 }
 443 EXPORT_SYMBOL_GPL(videobuf_to_dma_contig);
 444
 445 void videobuf_dma_contig_free(struct videobuf_queue *q,
 446                               struct videobuf_buffer *buf)
 447 {
 448         struct videobuf_dma_contig_memory *mem = buf->priv;
 449
 450         /* mmapped memory can't be freed here, otherwise mmapped region
 451            would be released, while still needed. In this case, the memory
 452            release should happen inside videobuf_vm_close().
 453            So, it should free memory only if the memory were allocated for
 454            read() operation.
 455          */
 456         if (buf->memory != V4L2_MEMORY_USERPTR)
 457                 return;
 458
 459         if (!mem)
 460                 return;
 461
 462         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 463
 464         /* handle user space pointer case */
 465         if (buf->baddr) {
 466                 videobuf_dma_contig_user_put(mem);
 467                 return;
 468         }
 469
 470         /* read() method */
 471         dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle);
 472         mem->vaddr = NULL;
 473 }
 474 EXPORT_SYMBOL_GPL(videobuf_dma_contig_free);
 475
 476 MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers");
 477 MODULE_AUTHOR("Magnus Damm");
 478 MODULE_LICENSE("GPL");