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 struct videobuf_buffer *__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_vaddr(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 struct videobuf_qtype_ops qops = {
 357         .magic        = MAGIC_QTYPE_OPS,
 358
 359         .alloc        = __videobuf_alloc,
 360         .iolock       = __videobuf_iolock,
 361         .mmap_mapper  = __videobuf_mmap_mapper,
 362         .vaddr        = __videobuf_to_vaddr,
 363 };
 364
 365 void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
 366                                     const struct videobuf_queue_ops *ops,
 367                                     struct device *dev,
 368                                     spinlock_t *irqlock,
 369                                     enum v4l2_buf_type type,
 370                                     enum v4l2_field field,
 371                                     unsigned int msize,
 372                                     void *priv)
 373 {
 374         videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
 375                                  priv, &qops);
 376 }
 377 EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init);
 378
 379 dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
 380 {
 381         struct videobuf_dma_contig_memory *mem = buf->priv;
 382
 383         BUG_ON(!mem);
 384         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 385
 386         return mem->dma_handle;
 387 }
 388 EXPORT_SYMBOL_GPL(videobuf_to_dma_contig);
 389
 390 void videobuf_dma_contig_free(struct videobuf_queue *q,
 391                               struct videobuf_buffer *buf)
 392 {
 393         struct videobuf_dma_contig_memory *mem = buf->priv;
 394
 395         /* mmapped memory can't be freed here, otherwise mmapped region
 396            would be released, while still needed. In this case, the memory
 397            release should happen inside videobuf_vm_close().
 398            So, it should free memory only if the memory were allocated for
 399            read() operation.
 400          */
 401         if (buf->memory != V4L2_MEMORY_USERPTR)
 402                 return;
 403
 404         if (!mem)
 405                 return;
 406
 407         MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 408
 409         /* handle user space pointer case */
 410         if (buf->baddr) {
 411                 videobuf_dma_contig_user_put(mem);
 412                 return;
 413         }
 414
 415         /* read() method */
 416         dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle);
 417         mem->vaddr = NULL;
 418 }
 419 EXPORT_SYMBOL_GPL(videobuf_dma_contig_free);
 420
 421 MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers");
 422 MODULE_AUTHOR("Magnus Damm");
 423 MODULE_LICENSE("GPL");