Pileus Git - ~andy/linux/blob - drivers/media/v4l2-core/videobuf2-dma-contig.c

   1 /*
   2  * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Pawel Osciak <pawel@osciak.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation.
  11  */
  12
  13 #include <linux/dma-buf.h>
  14 #include <linux/module.h>
  15 #include <linux/scatterlist.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/dma-mapping.h>
  19
  20 #include <media/videobuf2-core.h>
  21 #include <media/videobuf2-dma-contig.h>
  22 #include <media/videobuf2-memops.h>
  23
  24 struct vb2_dc_conf {
  25         struct device           *dev;
  26 };
  27
  28 struct vb2_dc_buf {
  29         struct device                   *dev;
  30         void                            *vaddr;
  31         unsigned long                   size;
  32         dma_addr_t                      dma_addr;
  33         enum dma_data_direction         dma_dir;
  34         struct sg_table                 *dma_sgt;
  35
  36         /* MMAP related */
  37         struct vb2_vmarea_handler       handler;
  38         atomic_t                        refcount;
  39
  40         /* USERPTR related */
  41         struct vm_area_struct           *vma;
  42
  43         /* DMABUF related */
  44         struct dma_buf_attachment       *db_attach;
  45 };
  46
  47 /*********************************************/
  48 /*        scatterlist table functions        */
  49 /*********************************************/
  50
  51
  52 static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
  53         void (*cb)(struct page *pg))
  54 {
  55         struct scatterlist *s;
  56         unsigned int i;
  57
  58         for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
  59                 struct page *page = sg_page(s);
  60                 unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
  61                         >> PAGE_SHIFT;
  62                 unsigned int j;
  63
  64                 for (j = 0; j < n_pages; ++j, ++page)
  65                         cb(page);
  66         }
  67 }
  68
  69 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
  70 {
  71         struct scatterlist *s;
  72         dma_addr_t expected = sg_dma_address(sgt->sgl);
  73         unsigned int i;
  74         unsigned long size = 0;
  75
  76         for_each_sg(sgt->sgl, s, sgt->nents, i) {
  77                 if (sg_dma_address(s) != expected)
  78                         break;
  79                 expected = sg_dma_address(s) + sg_dma_len(s);
  80                 size += sg_dma_len(s);
  81         }
  82         return size;
  83 }
  84
  85 /*********************************************/
  86 /*         callbacks for all buffers         */
  87 /*********************************************/
  88
  89 static void *vb2_dc_cookie(void *buf_priv)
  90 {
  91         struct vb2_dc_buf *buf = buf_priv;
  92
  93         return &buf->dma_addr;
  94 }
  95
  96 static void *vb2_dc_vaddr(void *buf_priv)
  97 {
  98         struct vb2_dc_buf *buf = buf_priv;
  99
 100         return buf->vaddr;
 101 }
 102
 103 static unsigned int vb2_dc_num_users(void *buf_priv)
 104 {
 105         struct vb2_dc_buf *buf = buf_priv;
 106
 107         return atomic_read(&buf->refcount);
 108 }
 109
 110 static void vb2_dc_prepare(void *buf_priv)
 111 {
 112         struct vb2_dc_buf *buf = buf_priv;
 113         struct sg_table *sgt = buf->dma_sgt;
 114
 115         /* DMABUF exporter will flush the cache for us */
 116         if (!sgt || buf->db_attach)
 117                 return;
 118
 119         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 120 }
 121
 122 static void vb2_dc_finish(void *buf_priv)
 123 {
 124         struct vb2_dc_buf *buf = buf_priv;
 125         struct sg_table *sgt = buf->dma_sgt;
 126
 127         /* DMABUF exporter will flush the cache for us */
 128         if (!sgt || buf->db_attach)
 129                 return;
 130
 131         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 132 }
 133
 134 /*********************************************/
 135 /*        callbacks for MMAP buffers         */
 136 /*********************************************/
 137
 138 static void vb2_dc_put(void *buf_priv)
 139 {
 140         struct vb2_dc_buf *buf = buf_priv;
 141
 142         if (!atomic_dec_and_test(&buf->refcount))
 143                 return;
 144
 145         dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
 146         kfree(buf);
 147 }
 148
 149 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 150 {
 151         struct vb2_dc_conf *conf = alloc_ctx;
 152         struct device *dev = conf->dev;
 153         struct vb2_dc_buf *buf;
 154
 155         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 156         if (!buf)
 157                 return ERR_PTR(-ENOMEM);
 158
 159         buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
 160         if (!buf->vaddr) {
 161                 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 162                 kfree(buf);
 163                 return ERR_PTR(-ENOMEM);
 164         }
 165
 166         buf->dev = dev;
 167         buf->size = size;
 168
 169         buf->handler.refcount = &buf->refcount;
 170         buf->handler.put = vb2_dc_put;
 171         buf->handler.arg = buf;
 172
 173         atomic_inc(&buf->refcount);
 174
 175         return buf;
 176 }
 177
 178 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 179 {
 180         struct vb2_dc_buf *buf = buf_priv;
 181         int ret;
 182
 183         if (!buf) {
 184                 printk(KERN_ERR "No buffer to map\n");
 185                 return -EINVAL;
 186         }
 187
 188         /*
 189          * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
 190          * map whole buffer
 191          */
 192         vma->vm_pgoff = 0;
 193
 194         ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
 195                 buf->dma_addr, buf->size);
 196
 197         if (ret) {
 198                 pr_err("Remapping memory failed, error: %d\n", ret);
 199                 return ret;
 200         }
 201
 202         vma->vm_flags           |= VM_DONTEXPAND | VM_DONTDUMP;
 203         vma->vm_private_data    = &buf->handler;
 204         vma->vm_ops             = &vb2_common_vm_ops;
 205
 206         vma->vm_ops->open(vma);
 207
 208         pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
 209                 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
 210                 buf->size);
 211
 212         return 0;
 213 }
 214
 215 /*********************************************/
 216 /*       callbacks for USERPTR buffers       */
 217 /*********************************************/
 218
 219 static inline int vma_is_io(struct vm_area_struct *vma)
 220 {
 221         return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
 222 }
 223
 224 static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
 225         int n_pages, struct vm_area_struct *vma, int write)
 226 {
 227         if (vma_is_io(vma)) {
 228                 unsigned int i;
 229
 230                 for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
 231                         unsigned long pfn;
 232                         int ret = follow_pfn(vma, start, &pfn);
 233
 234                         if (ret) {
 235                                 pr_err("no page for address %lu\n", start);
 236                                 return ret;
 237                         }
 238                         pages[i] = pfn_to_page(pfn);
 239                 }
 240         } else {
 241                 int n;
 242
 243                 n = get_user_pages(current, current->mm, start & PAGE_MASK,
 244                         n_pages, write, 1, pages, NULL);
 245                 /* negative error means that no page was pinned */
 246                 n = max(n, 0);
 247                 if (n != n_pages) {
 248                         pr_err("got only %d of %d user pages\n", n, n_pages);
 249                         while (n)
 250                                 put_page(pages[--n]);
 251                         return -EFAULT;
 252                 }
 253         }
 254
 255         return 0;
 256 }
 257
 258 static void vb2_dc_put_dirty_page(struct page *page)
 259 {
 260         set_page_dirty_lock(page);
 261         put_page(page);
 262 }
 263
 264 static void vb2_dc_put_userptr(void *buf_priv)
 265 {
 266         struct vb2_dc_buf *buf = buf_priv;
 267         struct sg_table *sgt = buf->dma_sgt;
 268
 269         dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 270         if (!vma_is_io(buf->vma))
 271                 vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
 272
 273         sg_free_table(sgt);
 274         kfree(sgt);
 275         vb2_put_vma(buf->vma);
 276         kfree(buf);
 277 }
 278
 279 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 280         unsigned long size, int write)
 281 {
 282         struct vb2_dc_conf *conf = alloc_ctx;
 283         struct vb2_dc_buf *buf;
 284         unsigned long start;
 285         unsigned long end;
 286         unsigned long offset;
 287         struct page **pages;
 288         int n_pages;
 289         int ret = 0;
 290         struct vm_area_struct *vma;
 291         struct sg_table *sgt;
 292         unsigned long contig_size;
 293
 294         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 295         if (!buf)
 296                 return ERR_PTR(-ENOMEM);
 297
 298         buf->dev = conf->dev;
 299         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 300
 301         start = vaddr & PAGE_MASK;
 302         offset = vaddr & ~PAGE_MASK;
 303         end = PAGE_ALIGN(vaddr + size);
 304         n_pages = (end - start) >> PAGE_SHIFT;
 305
 306         pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
 307         if (!pages) {
 308                 ret = -ENOMEM;
 309                 pr_err("failed to allocate pages table\n");
 310                 goto fail_buf;
 311         }
 312
 313         /* current->mm->mmap_sem is taken by videobuf2 core */
 314         vma = find_vma(current->mm, vaddr);
 315         if (!vma) {
 316                 pr_err("no vma for address %lu\n", vaddr);
 317                 ret = -EFAULT;
 318                 goto fail_pages;
 319         }
 320
 321         if (vma->vm_end < vaddr + size) {
 322                 pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
 323                 ret = -EFAULT;
 324                 goto fail_pages;
 325         }
 326
 327         buf->vma = vb2_get_vma(vma);
 328         if (!buf->vma) {
 329                 pr_err("failed to copy vma\n");
 330                 ret = -ENOMEM;
 331                 goto fail_pages;
 332         }
 333
 334         /* extract page list from userspace mapping */
 335         ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
 336         if (ret) {
 337                 pr_err("failed to get user pages\n");
 338                 goto fail_vma;
 339         }
 340
 341         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 342         if (!sgt) {
 343                 pr_err("failed to allocate sg table\n");
 344                 ret = -ENOMEM;
 345                 goto fail_get_user_pages;
 346         }
 347
 348         ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
 349                 offset, size, GFP_KERNEL);
 350         if (ret) {
 351                 pr_err("failed to initialize sg table\n");
 352                 goto fail_sgt;
 353         }
 354
 355         /* pages are no longer needed */
 356         kfree(pages);
 357         pages = NULL;
 358
 359         sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
 360                 buf->dma_dir);
 361         if (sgt->nents <= 0) {
 362                 pr_err("failed to map scatterlist\n");
 363                 ret = -EIO;
 364                 goto fail_sgt_init;
 365         }
 366
 367         contig_size = vb2_dc_get_contiguous_size(sgt);
 368         if (contig_size < size) {
 369                 pr_err("contiguous mapping is too small %lu/%lu\n",
 370                         contig_size, size);
 371                 ret = -EFAULT;
 372                 goto fail_map_sg;
 373         }
 374
 375         buf->dma_addr = sg_dma_address(sgt->sgl);
 376         buf->size = size;
 377         buf->dma_sgt = sgt;
 378
 379         return buf;
 380
 381 fail_map_sg:
 382         dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 383
 384 fail_sgt_init:
 385         if (!vma_is_io(buf->vma))
 386                 vb2_dc_sgt_foreach_page(sgt, put_page);
 387         sg_free_table(sgt);
 388
 389 fail_sgt:
 390         kfree(sgt);
 391
 392 fail_get_user_pages:
 393         if (pages && !vma_is_io(buf->vma))
 394                 while (n_pages)
 395                         put_page(pages[--n_pages]);
 396
 397 fail_vma:
 398         vb2_put_vma(buf->vma);
 399
 400 fail_pages:
 401         kfree(pages); /* kfree is NULL-proof */
 402
 403 fail_buf:
 404         kfree(buf);
 405
 406         return ERR_PTR(ret);
 407 }
 408
 409 /*********************************************/
 410 /*       callbacks for DMABUF buffers        */
 411 /*********************************************/
 412
 413 static int vb2_dc_map_dmabuf(void *mem_priv)
 414 {
 415         struct vb2_dc_buf *buf = mem_priv;
 416         struct sg_table *sgt;
 417         unsigned long contig_size;
 418
 419         if (WARN_ON(!buf->db_attach)) {
 420                 pr_err("trying to pin a non attached buffer\n");
 421                 return -EINVAL;
 422         }
 423
 424         if (WARN_ON(buf->dma_sgt)) {
 425                 pr_err("dmabuf buffer is already pinned\n");
 426                 return 0;
 427         }
 428
 429         /* get the associated scatterlist for this buffer */
 430         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 431         if (IS_ERR_OR_NULL(sgt)) {
 432                 pr_err("Error getting dmabuf scatterlist\n");
 433                 return -EINVAL;
 434         }
 435
 436         /* checking if dmabuf is big enough to store contiguous chunk */
 437         contig_size = vb2_dc_get_contiguous_size(sgt);
 438         if (contig_size < buf->size) {
 439                 pr_err("contiguous chunk is too small %lu/%lu b\n",
 440                         contig_size, buf->size);
 441                 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 442                 return -EFAULT;
 443         }
 444
 445         buf->dma_addr = sg_dma_address(sgt->sgl);
 446         buf->dma_sgt = sgt;
 447
 448         return 0;
 449 }
 450
 451 static void vb2_dc_unmap_dmabuf(void *mem_priv)
 452 {
 453         struct vb2_dc_buf *buf = mem_priv;
 454         struct sg_table *sgt = buf->dma_sgt;
 455
 456         if (WARN_ON(!buf->db_attach)) {
 457                 pr_err("trying to unpin a not attached buffer\n");
 458                 return;
 459         }
 460
 461         if (WARN_ON(!sgt)) {
 462                 pr_err("dmabuf buffer is already unpinned\n");
 463                 return;
 464         }
 465
 466         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 467
 468         buf->dma_addr = 0;
 469         buf->dma_sgt = NULL;
 470 }
 471
 472 static void vb2_dc_detach_dmabuf(void *mem_priv)
 473 {
 474         struct vb2_dc_buf *buf = mem_priv;
 475
 476         /* if vb2 works correctly you should never detach mapped buffer */
 477         if (WARN_ON(buf->dma_addr))
 478                 vb2_dc_unmap_dmabuf(buf);
 479
 480         /* detach this attachment */
 481         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 482         kfree(buf);
 483 }
 484
 485 static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 486         unsigned long size, int write)
 487 {
 488         struct vb2_dc_conf *conf = alloc_ctx;
 489         struct vb2_dc_buf *buf;
 490         struct dma_buf_attachment *dba;
 491
 492         if (dbuf->size < size)
 493                 return ERR_PTR(-EFAULT);
 494
 495         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 496         if (!buf)
 497                 return ERR_PTR(-ENOMEM);
 498
 499         buf->dev = conf->dev;
 500         /* create attachment for the dmabuf with the user device */
 501         dba = dma_buf_attach(dbuf, buf->dev);
 502         if (IS_ERR(dba)) {
 503                 pr_err("failed to attach dmabuf\n");
 504                 kfree(buf);
 505                 return dba;
 506         }
 507
 508         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 509         buf->size = size;
 510         buf->db_attach = dba;
 511
 512         return buf;
 513 }
 514
 515 /*********************************************/
 516 /*       DMA CONTIG exported functions       */
 517 /*********************************************/
 518
 519 const struct vb2_mem_ops vb2_dma_contig_memops = {
 520         .alloc          = vb2_dc_alloc,
 521         .put            = vb2_dc_put,
 522         .cookie         = vb2_dc_cookie,
 523         .vaddr          = vb2_dc_vaddr,
 524         .mmap           = vb2_dc_mmap,
 525         .get_userptr    = vb2_dc_get_userptr,
 526         .put_userptr    = vb2_dc_put_userptr,
 527         .prepare        = vb2_dc_prepare,
 528         .finish         = vb2_dc_finish,
 529         .map_dmabuf     = vb2_dc_map_dmabuf,
 530         .unmap_dmabuf   = vb2_dc_unmap_dmabuf,
 531         .attach_dmabuf  = vb2_dc_attach_dmabuf,
 532         .detach_dmabuf  = vb2_dc_detach_dmabuf,
 533         .num_users      = vb2_dc_num_users,
 534 };
 535 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
 536
 537 void *vb2_dma_contig_init_ctx(struct device *dev)
 538 {
 539         struct vb2_dc_conf *conf;
 540
 541         conf = kzalloc(sizeof *conf, GFP_KERNEL);
 542         if (!conf)
 543                 return ERR_PTR(-ENOMEM);
 544
 545         conf->dev = dev;
 546
 547         return conf;
 548 }
 549 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
 550
 551 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
 552 {
 553         kfree(alloc_ctx);
 554 }
 555 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
 556
 557 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
 558 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 559 MODULE_LICENSE("GPL");