drivers/media/v4l2-core/videobuf2-dma-sg.c

   1 /*
   2  * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.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/module.h>
  14 #include <linux/mm.h>
  15 #include <linux/scatterlist.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/vmalloc.h>
  19
  20 #include <media/videobuf2-core.h>
  21 #include <media/videobuf2-memops.h>
  22 #include <media/videobuf2-dma-sg.h>
  23
  24 static int debug;
  25 module_param(debug, int, 0644);
  26
  27 #define dprintk(level, fmt, arg...)                                     \
  28         do {                                                            \
  29                 if (debug >= level)                                     \
  30                         printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);  \
  31         } while (0)
  32
  33 struct vb2_dma_sg_conf {
  34         struct device           *dev;
  35 };
  36
  37 struct vb2_dma_sg_buf {
  38         struct device                   *dev;
  39         void                            *vaddr;
  40         struct page                     **pages;
  41         int                             offset;
  42         enum dma_data_direction         dma_dir;
  43         struct sg_table                 sg_table;
  44         /*
  45          * This will point to sg_table when used with the MMAP or USERPTR
  46          * memory model, and to the dma_buf sglist when used with the
  47          * DMABUF memory model.
  48          */
  49         struct sg_table                 *dma_sgt;
  50         size_t                          size;
  51         unsigned int                    num_pages;
  52         atomic_t                        refcount;
  53         struct vb2_vmarea_handler       handler;
  54         struct vm_area_struct           *vma;
  55
  56         struct dma_buf_attachment       *db_attach;
  57 };
  58
  59 static void vb2_dma_sg_put(void *buf_priv);
  60
  61 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
  62                 gfp_t gfp_flags)
  63 {
  64         unsigned int last_page = 0;
  65         int size = buf->size;
  66
  67         while (size > 0) {
  68                 struct page *pages;
  69                 int order;
  70                 int i;
  71
  72                 order = get_order(size);
  73                 /* Dont over allocate*/
  74                 if ((PAGE_SIZE << order) > size)
  75                         order--;
  76
  77                 pages = NULL;
  78                 while (!pages) {
  79                         pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
  80                                         __GFP_NOWARN | gfp_flags, order);
  81                         if (pages)
  82                                 break;
  83
  84                         if (order == 0) {
  85                                 while (last_page--)
  86                                         __free_page(buf->pages[last_page]);
  87                                 return -ENOMEM;
  88                         }
  89                         order--;
  90                 }
  91
  92                 split_page(pages, order);
  93                 for (i = 0; i < (1 << order); i++)
  94                         buf->pages[last_page++] = &pages[i];
  95
  96                 size -= PAGE_SIZE << order;
  97         }
  98
  99         return 0;
 100 }
 101
 102 static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
 103                               enum dma_data_direction dma_dir, gfp_t gfp_flags)
 104 {
 105         struct vb2_dma_sg_conf *conf = alloc_ctx;
 106         struct vb2_dma_sg_buf *buf;
 107         struct sg_table *sgt;
 108         int ret;
 109         int num_pages;
 110
 111         if (WARN_ON(alloc_ctx == NULL))
 112                 return NULL;
 113         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 114         if (!buf)
 115                 return NULL;
 116
 117         buf->vaddr = NULL;
 118         buf->dma_dir = dma_dir;
 119         buf->offset = 0;
 120         buf->size = size;
 121         /* size is already page aligned */
 122         buf->num_pages = size >> PAGE_SHIFT;
 123         buf->dma_sgt = &buf->sg_table;
 124
 125         buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
 126                              GFP_KERNEL);
 127         if (!buf->pages)
 128                 goto fail_pages_array_alloc;
 129
 130         ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
 131         if (ret)
 132                 goto fail_pages_alloc;
 133
 134         ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 135                         buf->num_pages, 0, size, GFP_KERNEL);
 136         if (ret)
 137                 goto fail_table_alloc;
 138
 139         /* Prevent the device from being released while the buffer is used */
 140         buf->dev = get_device(conf->dev);
 141
 142         sgt = &buf->sg_table;
 143         if (dma_map_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir) == 0)
 144                 goto fail_map;
 145         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 146
 147         buf->handler.refcount = &buf->refcount;
 148         buf->handler.put = vb2_dma_sg_put;
 149         buf->handler.arg = buf;
 150
 151         atomic_inc(&buf->refcount);
 152
 153         dprintk(1, "%s: Allocated buffer of %d pages\n",
 154                 __func__, buf->num_pages);
 155         return buf;
 156
 157 fail_map:
 158         put_device(buf->dev);
 159         sg_free_table(buf->dma_sgt);
 160 fail_table_alloc:
 161         num_pages = buf->num_pages;
 162         while (num_pages--)
 163                 __free_page(buf->pages[num_pages]);
 164 fail_pages_alloc:
 165         kfree(buf->pages);
 166 fail_pages_array_alloc:
 167         kfree(buf);
 168         return NULL;
 169 }
 170
 171 static void vb2_dma_sg_put(void *buf_priv)
 172 {
 173         struct vb2_dma_sg_buf *buf = buf_priv;
 174         struct sg_table *sgt = &buf->sg_table;
 175         int i = buf->num_pages;
 176
 177         if (atomic_dec_and_test(&buf->refcount)) {
 178                 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
 179                         buf->num_pages);
 180                 dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 181                 if (buf->vaddr)
 182                         vm_unmap_ram(buf->vaddr, buf->num_pages);
 183                 sg_free_table(buf->dma_sgt);
 184                 while (--i >= 0)
 185                         __free_page(buf->pages[i]);
 186                 kfree(buf->pages);
 187                 put_device(buf->dev);
 188                 kfree(buf);
 189         }
 190 }
 191
 192 static void vb2_dma_sg_prepare(void *buf_priv)
 193 {
 194         struct vb2_dma_sg_buf *buf = buf_priv;
 195         struct sg_table *sgt = buf->dma_sgt;
 196
 197         /* DMABUF exporter will flush the cache for us */
 198         if (buf->db_attach)
 199                 return;
 200
 201         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 202 }
 203
 204 static void vb2_dma_sg_finish(void *buf_priv)
 205 {
 206         struct vb2_dma_sg_buf *buf = buf_priv;
 207         struct sg_table *sgt = buf->dma_sgt;
 208
 209         /* DMABUF exporter will flush the cache for us */
 210         if (buf->db_attach)
 211                 return;
 212
 213         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 214 }
 215
 216 static inline int vma_is_io(struct vm_area_struct *vma)
 217 {
 218         return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
 219 }
 220
 221 static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
 222                                     unsigned long size,
 223                                     enum dma_data_direction dma_dir)
 224 {
 225         struct vb2_dma_sg_conf *conf = alloc_ctx;
 226         struct vb2_dma_sg_buf *buf;
 227         unsigned long first, last;
 228         int num_pages_from_user;
 229         struct vm_area_struct *vma;
 230         struct sg_table *sgt;
 231
 232         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 233         if (!buf)
 234                 return NULL;
 235
 236         buf->vaddr = NULL;
 237         buf->dev = conf->dev;
 238         buf->dma_dir = dma_dir;
 239         buf->offset = vaddr & ~PAGE_MASK;
 240         buf->size = size;
 241         buf->dma_sgt = &buf->sg_table;
 242
 243         first = (vaddr           & PAGE_MASK) >> PAGE_SHIFT;
 244         last  = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
 245         buf->num_pages = last - first + 1;
 246
 247         buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
 248                              GFP_KERNEL);
 249         if (!buf->pages)
 250                 goto userptr_fail_alloc_pages;
 251
 252         vma = find_vma(current->mm, vaddr);
 253         if (!vma) {
 254                 dprintk(1, "no vma for address %lu\n", vaddr);
 255                 goto userptr_fail_find_vma;
 256         }
 257
 258         if (vma->vm_end < vaddr + size) {
 259                 dprintk(1, "vma at %lu is too small for %lu bytes\n",
 260                         vaddr, size);
 261                 goto userptr_fail_find_vma;
 262         }
 263
 264         buf->vma = vb2_get_vma(vma);
 265         if (!buf->vma) {
 266                 dprintk(1, "failed to copy vma\n");
 267                 goto userptr_fail_find_vma;
 268         }
 269
 270         if (vma_is_io(buf->vma)) {
 271                 for (num_pages_from_user = 0;
 272                      num_pages_from_user < buf->num_pages;
 273                      ++num_pages_from_user, vaddr += PAGE_SIZE) {
 274                         unsigned long pfn;
 275
 276                         if (follow_pfn(vma, vaddr, &pfn)) {
 277                                 dprintk(1, "no page for address %lu\n", vaddr);
 278                                 break;
 279                         }
 280                         buf->pages[num_pages_from_user] = pfn_to_page(pfn);
 281                 }
 282         } else
 283                 num_pages_from_user = get_user_pages(current, current->mm,
 284                                              vaddr & PAGE_MASK,
 285                                              buf->num_pages,
 286                                              buf->dma_dir == DMA_FROM_DEVICE,
 287                                              1, /* force */
 288                                              buf->pages,
 289                                              NULL);
 290
 291         if (num_pages_from_user != buf->num_pages)
 292                 goto userptr_fail_get_user_pages;
 293
 294         if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 295                         buf->num_pages, buf->offset, size, 0))
 296                 goto userptr_fail_alloc_table_from_pages;
 297
 298         sgt = &buf->sg_table;
 299         if (dma_map_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir) == 0)
 300                 goto userptr_fail_map;
 301         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 302         return buf;
 303
 304 userptr_fail_map:
 305         sg_free_table(&buf->sg_table);
 306 userptr_fail_alloc_table_from_pages:
 307 userptr_fail_get_user_pages:
 308         dprintk(1, "get_user_pages requested/got: %d/%d]\n",
 309                 buf->num_pages, num_pages_from_user);
 310         if (!vma_is_io(buf->vma))
 311                 while (--num_pages_from_user >= 0)
 312                         put_page(buf->pages[num_pages_from_user]);
 313         vb2_put_vma(buf->vma);
 314 userptr_fail_find_vma:
 315         kfree(buf->pages);
 316 userptr_fail_alloc_pages:
 317         kfree(buf);
 318         return NULL;
 319 }
 320
 321 /*
 322  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 323  *               be used
 324  */
 325 static void vb2_dma_sg_put_userptr(void *buf_priv)
 326 {
 327         struct vb2_dma_sg_buf *buf = buf_priv;
 328         struct sg_table *sgt = &buf->sg_table;
 329         int i = buf->num_pages;
 330
 331         dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
 332                __func__, buf->num_pages);
 333         dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 334         if (buf->vaddr)
 335                 vm_unmap_ram(buf->vaddr, buf->num_pages);
 336         sg_free_table(buf->dma_sgt);
 337         while (--i >= 0) {
 338                 if (buf->dma_dir == DMA_FROM_DEVICE)
 339                         set_page_dirty_lock(buf->pages[i]);
 340                 if (!vma_is_io(buf->vma))
 341                         put_page(buf->pages[i]);
 342         }
 343         kfree(buf->pages);
 344         vb2_put_vma(buf->vma);
 345         kfree(buf);
 346 }
 347
 348 static void *vb2_dma_sg_vaddr(void *buf_priv)
 349 {
 350         struct vb2_dma_sg_buf *buf = buf_priv;
 351
 352         BUG_ON(!buf);
 353
 354         if (!buf->vaddr) {
 355                 if (buf->db_attach)
 356                         buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
 357                 else
 358                         buf->vaddr = vm_map_ram(buf->pages,
 359                                         buf->num_pages, -1, PAGE_KERNEL);
 360         }
 361
 362         /* add offset in case userptr is not page-aligned */
 363         return buf->vaddr ? buf->vaddr + buf->offset : NULL;
 364 }
 365
 366 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
 367 {
 368         struct vb2_dma_sg_buf *buf = buf_priv;
 369
 370         return atomic_read(&buf->refcount);
 371 }
 372
 373 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
 374 {
 375         struct vb2_dma_sg_buf *buf = buf_priv;
 376         unsigned long uaddr = vma->vm_start;
 377         unsigned long usize = vma->vm_end - vma->vm_start;
 378         int i = 0;
 379
 380         if (!buf) {
 381                 printk(KERN_ERR "No memory to map\n");
 382                 return -EINVAL;
 383         }
 384
 385         do {
 386                 int ret;
 387
 388                 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
 389                 if (ret) {
 390                         printk(KERN_ERR "Remapping memory, error: %d\n", ret);
 391                         return ret;
 392                 }
 393
 394                 uaddr += PAGE_SIZE;
 395                 usize -= PAGE_SIZE;
 396         } while (usize > 0);
 397
 398
 399         /*
 400          * Use common vm_area operations to track buffer refcount.
 401          */
 402         vma->vm_private_data    = &buf->handler;
 403         vma->vm_ops             = &vb2_common_vm_ops;
 404
 405         vma->vm_ops->open(vma);
 406
 407         return 0;
 408 }
 409
 410 /*********************************************/
 411 /*       callbacks for DMABUF buffers        */
 412 /*********************************************/
 413
 414 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
 415 {
 416         struct vb2_dma_sg_buf *buf = mem_priv;
 417         struct sg_table *sgt;
 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(sgt)) {
 432                 pr_err("Error getting dmabuf scatterlist\n");
 433                 return -EINVAL;
 434         }
 435
 436         buf->dma_sgt = sgt;
 437         buf->vaddr = NULL;
 438
 439         return 0;
 440 }
 441
 442 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
 443 {
 444         struct vb2_dma_sg_buf *buf = mem_priv;
 445         struct sg_table *sgt = buf->dma_sgt;
 446
 447         if (WARN_ON(!buf->db_attach)) {
 448                 pr_err("trying to unpin a not attached buffer\n");
 449                 return;
 450         }
 451
 452         if (WARN_ON(!sgt)) {
 453                 pr_err("dmabuf buffer is already unpinned\n");
 454                 return;
 455         }
 456
 457         if (buf->vaddr) {
 458                 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
 459                 buf->vaddr = NULL;
 460         }
 461         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 462
 463         buf->dma_sgt = NULL;
 464 }
 465
 466 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
 467 {
 468         struct vb2_dma_sg_buf *buf = mem_priv;
 469
 470         /* if vb2 works correctly you should never detach mapped buffer */
 471         if (WARN_ON(buf->dma_sgt))
 472                 vb2_dma_sg_unmap_dmabuf(buf);
 473
 474         /* detach this attachment */
 475         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 476         kfree(buf);
 477 }
 478
 479 static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 480         unsigned long size, enum dma_data_direction dma_dir)
 481 {
 482         struct vb2_dma_sg_conf *conf = alloc_ctx;
 483         struct vb2_dma_sg_buf *buf;
 484         struct dma_buf_attachment *dba;
 485
 486         if (dbuf->size < size)
 487                 return ERR_PTR(-EFAULT);
 488
 489         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 490         if (!buf)
 491                 return ERR_PTR(-ENOMEM);
 492
 493         buf->dev = conf->dev;
 494         /* create attachment for the dmabuf with the user device */
 495         dba = dma_buf_attach(dbuf, buf->dev);
 496         if (IS_ERR(dba)) {
 497                 pr_err("failed to attach dmabuf\n");
 498                 kfree(buf);
 499                 return dba;
 500         }
 501
 502         buf->dma_dir = dma_dir;
 503         buf->size = size;
 504         buf->db_attach = dba;
 505
 506         return buf;
 507 }
 508
 509 static void *vb2_dma_sg_cookie(void *buf_priv)
 510 {
 511         struct vb2_dma_sg_buf *buf = buf_priv;
 512
 513         return buf->dma_sgt;
 514 }
 515
 516 const struct vb2_mem_ops vb2_dma_sg_memops = {
 517         .alloc          = vb2_dma_sg_alloc,
 518         .put            = vb2_dma_sg_put,
 519         .get_userptr    = vb2_dma_sg_get_userptr,
 520         .put_userptr    = vb2_dma_sg_put_userptr,
 521         .prepare        = vb2_dma_sg_prepare,
 522         .finish         = vb2_dma_sg_finish,
 523         .vaddr          = vb2_dma_sg_vaddr,
 524         .mmap           = vb2_dma_sg_mmap,
 525         .num_users      = vb2_dma_sg_num_users,
 526         .map_dmabuf     = vb2_dma_sg_map_dmabuf,
 527         .unmap_dmabuf   = vb2_dma_sg_unmap_dmabuf,
 528         .attach_dmabuf  = vb2_dma_sg_attach_dmabuf,
 529         .detach_dmabuf  = vb2_dma_sg_detach_dmabuf,
 530         .cookie         = vb2_dma_sg_cookie,
 531 };
 532 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
 533
 534 void *vb2_dma_sg_init_ctx(struct device *dev)
 535 {
 536         struct vb2_dma_sg_conf *conf;
 537
 538         conf = kzalloc(sizeof(*conf), GFP_KERNEL);
 539         if (!conf)
 540                 return ERR_PTR(-ENOMEM);
 541
 542         conf->dev = dev;
 543
 544         return conf;
 545 }
 546 EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx);
 547
 548 void vb2_dma_sg_cleanup_ctx(void *alloc_ctx)
 549 {
 550         if (!IS_ERR_OR_NULL(alloc_ctx))
 551                 kfree(alloc_ctx);
 552 }
 553 EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx);
 554
 555 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
 556 MODULE_AUTHOR("Andrzej Pietrasiewicz");
 557 MODULE_LICENSE("GPL");