drivers/gpu/drm/drm_prime.c

   1 /*
   2  * Copyright © 2012 Red Hat
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *      Dave Airlie <airlied@redhat.com>
  25  *      Rob Clark <rob.clark@linaro.org>
  26  *
  27  */
  28
  29 #include <linux/export.h>
  30 #include <linux/dma-buf.h>
  31 #include <drm/drmP.h>
  32
  33 /*
  34  * DMA-BUF/GEM Object references and lifetime overview:
  35  *
  36  * On the export the dma_buf holds a reference to the exporting GEM
  37  * object. It takes this reference in handle_to_fd_ioctl, when it
  38  * first calls .prime_export and stores the exporting GEM object in
  39  * the dma_buf priv. This reference is released when the dma_buf
  40  * object goes away in the driver .release function.
  41  *
  42  * On the import the importing GEM object holds a reference to the
  43  * dma_buf (which in turn holds a ref to the exporting GEM object).
  44  * It takes that reference in the fd_to_handle ioctl.
  45  * It calls dma_buf_get, creates an attachment to it and stores the
  46  * attachment in the GEM object. When this attachment is destroyed
  47  * when the imported object is destroyed, we remove the attachment
  48  * and drop the reference to the dma_buf.
  49  *
  50  * Thus the chain of references always flows in one direction
  51  * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
  52  *
  53  * Self-importing: if userspace is using PRIME as a replacement for flink
  54  * then it will get a fd->handle request for a GEM object that it created.
  55  * Drivers should detect this situation and return back the gem object
  56  * from the dma-buf private.
  57  */
  58
  59 struct drm_prime_member {
  60         struct list_head entry;
  61         struct dma_buf *dma_buf;
  62         uint32_t handle;
  63 };
  64
  65 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
  66                 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
  67                 int *prime_fd)
  68 {
  69         struct drm_gem_object *obj;
  70         void *buf;
  71         int ret;
  72
  73         obj = drm_gem_object_lookup(dev, file_priv, handle);
  74         if (!obj)
  75                 return -ENOENT;
  76
  77         mutex_lock(&file_priv->prime.lock);
  78         /* re-export the original imported object */
  79         if (obj->import_attach) {
  80                 get_dma_buf(obj->import_attach->dmabuf);
  81                 *prime_fd = dma_buf_fd(obj->import_attach->dmabuf, flags);
  82                 drm_gem_object_unreference_unlocked(obj);
  83                 mutex_unlock(&file_priv->prime.lock);
  84                 return 0;
  85         }
  86
  87         if (obj->export_dma_buf) {
  88                 get_dma_buf(obj->export_dma_buf);
  89                 *prime_fd = dma_buf_fd(obj->export_dma_buf, flags);
  90                 drm_gem_object_unreference_unlocked(obj);
  91         } else {
  92                 buf = dev->driver->gem_prime_export(dev, obj, flags);
  93                 if (IS_ERR(buf)) {
  94                         /* normally the created dma-buf takes ownership of the ref,
  95                          * but if that fails then drop the ref
  96                          */
  97                         drm_gem_object_unreference_unlocked(obj);
  98                         mutex_unlock(&file_priv->prime.lock);
  99                         return PTR_ERR(buf);
 100                 }
 101                 obj->export_dma_buf = buf;
 102                 *prime_fd = dma_buf_fd(buf, flags);
 103         }
 104         /* if we've exported this buffer the cheat and add it to the import list
 105          * so we get the correct handle back
 106          */
 107         ret = drm_prime_add_imported_buf_handle(&file_priv->prime,
 108                         obj->export_dma_buf, handle);
 109         if (ret) {
 110                 drm_gem_object_unreference_unlocked(obj);
 111                 mutex_unlock(&file_priv->prime.lock);
 112                 return ret;
 113         }
 114
 115         mutex_unlock(&file_priv->prime.lock);
 116         return 0;
 117 }
 118 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 119
 120 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 121                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 122 {
 123         struct dma_buf *dma_buf;
 124         struct drm_gem_object *obj;
 125         int ret;
 126
 127         dma_buf = dma_buf_get(prime_fd);
 128         if (IS_ERR(dma_buf))
 129                 return PTR_ERR(dma_buf);
 130
 131         mutex_lock(&file_priv->prime.lock);
 132
 133         ret = drm_prime_lookup_imported_buf_handle(&file_priv->prime,
 134                         dma_buf, handle);
 135         if (!ret) {
 136                 ret = 0;
 137                 goto out_put;
 138         }
 139
 140         /* never seen this one, need to import */
 141         obj = dev->driver->gem_prime_import(dev, dma_buf);
 142         if (IS_ERR(obj)) {
 143                 ret = PTR_ERR(obj);
 144                 goto out_put;
 145         }
 146
 147         ret = drm_gem_handle_create(file_priv, obj, handle);
 148         drm_gem_object_unreference_unlocked(obj);
 149         if (ret)
 150                 goto out_put;
 151
 152         ret = drm_prime_add_imported_buf_handle(&file_priv->prime,
 153                         dma_buf, *handle);
 154         if (ret)
 155                 goto fail;
 156
 157         mutex_unlock(&file_priv->prime.lock);
 158         return 0;
 159
 160 fail:
 161         /* hmm, if driver attached, we are relying on the free-object path
 162          * to detach.. which seems ok..
 163          */
 164         drm_gem_object_handle_unreference_unlocked(obj);
 165 out_put:
 166         dma_buf_put(dma_buf);
 167         mutex_unlock(&file_priv->prime.lock);
 168         return ret;
 169 }
 170 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 171
 172 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 173                                  struct drm_file *file_priv)
 174 {
 175         struct drm_prime_handle *args = data;
 176         uint32_t flags;
 177
 178         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 179                 return -EINVAL;
 180
 181         if (!dev->driver->prime_handle_to_fd)
 182                 return -ENOSYS;
 183
 184         /* check flags are valid */
 185         if (args->flags & ~DRM_CLOEXEC)
 186                 return -EINVAL;
 187
 188         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 189         flags = args->flags & DRM_CLOEXEC;
 190
 191         return dev->driver->prime_handle_to_fd(dev, file_priv,
 192                         args->handle, flags, &args->fd);
 193 }
 194
 195 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 196                                  struct drm_file *file_priv)
 197 {
 198         struct drm_prime_handle *args = data;
 199
 200         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 201                 return -EINVAL;
 202
 203         if (!dev->driver->prime_fd_to_handle)
 204                 return -ENOSYS;
 205
 206         return dev->driver->prime_fd_to_handle(dev, file_priv,
 207                         args->fd, &args->handle);
 208 }
 209
 210 /*
 211  * drm_prime_pages_to_sg
 212  *
 213  * this helper creates an sg table object from a set of pages
 214  * the driver is responsible for mapping the pages into the
 215  * importers address space
 216  */
 217 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 218 {
 219         struct sg_table *sg = NULL;
 220         struct scatterlist *iter;
 221         int i;
 222         int ret;
 223
 224         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 225         if (!sg)
 226                 goto out;
 227
 228         ret = sg_alloc_table(sg, nr_pages, GFP_KERNEL);
 229         if (ret)
 230                 goto out;
 231
 232         for_each_sg(sg->sgl, iter, nr_pages, i)
 233                 sg_set_page(iter, pages[i], PAGE_SIZE, 0);
 234
 235         return sg;
 236 out:
 237         kfree(sg);
 238         return NULL;
 239 }
 240 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 241
 242 /* export an sg table into an array of pages and addresses
 243    this is currently required by the TTM driver in order to do correct fault
 244    handling */
 245 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 246                                      dma_addr_t *addrs, int max_pages)
 247 {
 248         unsigned count;
 249         struct scatterlist *sg;
 250         struct page *page;
 251         u32 len, offset;
 252         int pg_index;
 253         dma_addr_t addr;
 254
 255         pg_index = 0;
 256         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 257                 len = sg->length;
 258                 offset = sg->offset;
 259                 page = sg_page(sg);
 260                 addr = sg_dma_address(sg);
 261
 262                 while (len > 0) {
 263                         if (WARN_ON(pg_index >= max_pages))
 264                                 return -1;
 265                         pages[pg_index] = page;
 266                         if (addrs)
 267                                 addrs[pg_index] = addr;
 268
 269                         page++;
 270                         addr += PAGE_SIZE;
 271                         len -= PAGE_SIZE;
 272                         pg_index++;
 273                 }
 274         }
 275         return 0;
 276 }
 277 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 278 /* helper function to cleanup a GEM/prime object */
 279 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 280 {
 281         struct dma_buf_attachment *attach;
 282         struct dma_buf *dma_buf;
 283         attach = obj->import_attach;
 284         if (sg)
 285                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 286         dma_buf = attach->dmabuf;
 287         dma_buf_detach(attach->dmabuf, attach);
 288         /* remove the reference */
 289         dma_buf_put(dma_buf);
 290 }
 291 EXPORT_SYMBOL(drm_prime_gem_destroy);
 292
 293 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 294 {
 295         INIT_LIST_HEAD(&prime_fpriv->head);
 296         mutex_init(&prime_fpriv->lock);
 297 }
 298 EXPORT_SYMBOL(drm_prime_init_file_private);
 299
 300 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 301 {
 302         struct drm_prime_member *member, *safe;
 303         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 304                 list_del(&member->entry);
 305                 kfree(member);
 306         }
 307 }
 308 EXPORT_SYMBOL(drm_prime_destroy_file_private);
 309
 310 int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
 311 {
 312         struct drm_prime_member *member;
 313
 314         member = kmalloc(sizeof(*member), GFP_KERNEL);
 315         if (!member)
 316                 return -ENOMEM;
 317
 318         member->dma_buf = dma_buf;
 319         member->handle = handle;
 320         list_add(&member->entry, &prime_fpriv->head);
 321         return 0;
 322 }
 323 EXPORT_SYMBOL(drm_prime_add_imported_buf_handle);
 324
 325 int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
 326 {
 327         struct drm_prime_member *member;
 328
 329         list_for_each_entry(member, &prime_fpriv->head, entry) {
 330                 if (member->dma_buf == dma_buf) {
 331                         *handle = member->handle;
 332                         return 0;
 333                 }
 334         }
 335         return -ENOENT;
 336 }
 337 EXPORT_SYMBOL(drm_prime_lookup_imported_buf_handle);
 338
 339 void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
 340 {
 341         struct drm_prime_member *member, *safe;
 342
 343         mutex_lock(&prime_fpriv->lock);
 344         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 345                 if (member->dma_buf == dma_buf) {
 346                         list_del(&member->entry);
 347                         kfree(member);
 348                 }
 349         }
 350         mutex_unlock(&prime_fpriv->lock);
 351 }
 352 EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle);