drivers/gpu/drm/drm_context.c

   1 /**
   2  * \file drm_context.c
   3  * IOCTLs for generic contexts
   4  *
   5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
   6  * \author Gareth Hughes <gareth@valinux.com>
   7  */
   8
   9 /*
  10  * Created: Fri Nov 24 18:31:37 2000 by gareth@valinux.com
  11  *
  12  * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
  13  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  14  * All Rights Reserved.
  15  *
  16  * Permission is hereby granted, free of charge, to any person obtaining a
  17  * copy of this software and associated documentation files (the "Software"),
  18  * to deal in the Software without restriction, including without limitation
  19  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  20  * and/or sell copies of the Software, and to permit persons to whom the
  21  * Software is furnished to do so, subject to the following conditions:
  22  *
  23  * The above copyright notice and this permission notice (including the next
  24  * paragraph) shall be included in all copies or substantial portions of the
  25  * Software.
  26  *
  27  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  28  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  29  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  30  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  31  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  32  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  33  * OTHER DEALINGS IN THE SOFTWARE.
  34  */
  35
  36 /*
  37  * ChangeLog:
  38  *  2001-11-16  Torsten Duwe <duwe@caldera.de>
  39  *              added context constructor/destructor hooks,
  40  *              needed by SiS driver's memory management.
  41  */
  42
  43 #include <drm/drmP.h>
  44
  45 /******************************************************************/
  46 /** \name Context bitmap support */
  47 /*@{*/
  48
  49 /**
  50  * Free a handle from the context bitmap.
  51  *
  52  * \param dev DRM device.
  53  * \param ctx_handle context handle.
  54  *
  55  * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
  56  * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
  57  * lock.
  58  */
  59 void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
  60 {
  61         mutex_lock(&dev->struct_mutex);
  62         idr_remove(&dev->ctx_idr, ctx_handle);
  63         mutex_unlock(&dev->struct_mutex);
  64 }
  65
  66 /**
  67  * Context bitmap allocation.
  68  *
  69  * \param dev DRM device.
  70  * \return (non-negative) context handle on success or a negative number on failure.
  71  *
  72  * Allocate a new idr from drm_device::ctx_idr while holding the
  73  * drm_device::struct_mutex lock.
  74  */
  75 static int drm_ctxbitmap_next(struct drm_device * dev)
  76 {
  77         int ret;
  78
  79         mutex_lock(&dev->struct_mutex);
  80         ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
  81                         GFP_KERNEL);
  82         mutex_unlock(&dev->struct_mutex);
  83         return ret;
  84 }
  85
  86 /**
  87  * Context bitmap initialization.
  88  *
  89  * \param dev DRM device.
  90  *
  91  * Initialise the drm_device::ctx_idr
  92  */
  93 int drm_ctxbitmap_init(struct drm_device * dev)
  94 {
  95         idr_init(&dev->ctx_idr);
  96         return 0;
  97 }
  98
  99 /**
 100  * Context bitmap cleanup.
 101  *
 102  * \param dev DRM device.
 103  *
 104  * Free all idr members using drm_ctx_sarea_free helper function
 105  * while holding the drm_device::struct_mutex lock.
 106  */
 107 void drm_ctxbitmap_cleanup(struct drm_device * dev)
 108 {
 109         mutex_lock(&dev->struct_mutex);
 110         idr_destroy(&dev->ctx_idr);
 111         mutex_unlock(&dev->struct_mutex);
 112 }
 113
 114 /*@}*/
 115
 116 /******************************************************************/
 117 /** \name Per Context SAREA Support */
 118 /*@{*/
 119
 120 /**
 121  * Get per-context SAREA.
 122  *
 123  * \param inode device inode.
 124  * \param file_priv DRM file private.
 125  * \param cmd command.
 126  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 127  * \return zero on success or a negative number on failure.
 128  *
 129  * Gets the map from drm_device::ctx_idr with the handle specified and
 130  * returns its handle.
 131  */
 132 int drm_getsareactx(struct drm_device *dev, void *data,
 133                     struct drm_file *file_priv)
 134 {
 135         struct drm_ctx_priv_map *request = data;
 136         struct drm_local_map *map;
 137         struct drm_map_list *_entry;
 138
 139         mutex_lock(&dev->struct_mutex);
 140
 141         map = idr_find(&dev->ctx_idr, request->ctx_id);
 142         if (!map) {
 143                 mutex_unlock(&dev->struct_mutex);
 144                 return -EINVAL;
 145         }
 146
 147         request->handle = NULL;
 148         list_for_each_entry(_entry, &dev->maplist, head) {
 149                 if (_entry->map == map) {
 150                         request->handle =
 151                             (void *)(unsigned long)_entry->user_token;
 152                         break;
 153                 }
 154         }
 155
 156         mutex_unlock(&dev->struct_mutex);
 157
 158         if (request->handle == NULL)
 159                 return -EINVAL;
 160
 161         return 0;
 162 }
 163
 164 /**
 165  * Set per-context SAREA.
 166  *
 167  * \param inode device inode.
 168  * \param file_priv DRM file private.
 169  * \param cmd command.
 170  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 171  * \return zero on success or a negative number on failure.
 172  *
 173  * Searches the mapping specified in \p arg and update the entry in
 174  * drm_device::ctx_idr with it.
 175  */
 176 int drm_setsareactx(struct drm_device *dev, void *data,
 177                     struct drm_file *file_priv)
 178 {
 179         struct drm_ctx_priv_map *request = data;
 180         struct drm_local_map *map = NULL;
 181         struct drm_map_list *r_list = NULL;
 182
 183         mutex_lock(&dev->struct_mutex);
 184         list_for_each_entry(r_list, &dev->maplist, head) {
 185                 if (r_list->map
 186                     && r_list->user_token == (unsigned long) request->handle)
 187                         goto found;
 188         }
 189       bad:
 190         mutex_unlock(&dev->struct_mutex);
 191         return -EINVAL;
 192
 193       found:
 194         map = r_list->map;
 195         if (!map)
 196                 goto bad;
 197
 198         if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
 199                 goto bad;
 200
 201         mutex_unlock(&dev->struct_mutex);
 202
 203         return 0;
 204 }
 205
 206 /*@}*/
 207
 208 /******************************************************************/
 209 /** \name The actual DRM context handling routines */
 210 /*@{*/
 211
 212 /**
 213  * Switch context.
 214  *
 215  * \param dev DRM device.
 216  * \param old old context handle.
 217  * \param new new context handle.
 218  * \return zero on success or a negative number on failure.
 219  *
 220  * Attempt to set drm_device::context_flag.
 221  */
 222 static int drm_context_switch(struct drm_device * dev, int old, int new)
 223 {
 224         if (test_and_set_bit(0, &dev->context_flag)) {
 225                 DRM_ERROR("Reentering -- FIXME\n");
 226                 return -EBUSY;
 227         }
 228
 229         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 230
 231         if (new == dev->last_context) {
 232                 clear_bit(0, &dev->context_flag);
 233                 return 0;
 234         }
 235
 236         return 0;
 237 }
 238
 239 /**
 240  * Complete context switch.
 241  *
 242  * \param dev DRM device.
 243  * \param new new context handle.
 244  * \return zero on success or a negative number on failure.
 245  *
 246  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 247  * hardware lock is held, clears the drm_device::context_flag and wakes up
 248  * drm_device::context_wait.
 249  */
 250 static int drm_context_switch_complete(struct drm_device *dev,
 251                                        struct drm_file *file_priv, int new)
 252 {
 253         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 254         dev->last_switch = jiffies;
 255
 256         if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 257                 DRM_ERROR("Lock isn't held after context switch\n");
 258         }
 259
 260         /* If a context switch is ever initiated
 261            when the kernel holds the lock, release
 262            that lock here. */
 263         clear_bit(0, &dev->context_flag);
 264         wake_up(&dev->context_wait);
 265
 266         return 0;
 267 }
 268
 269 /**
 270  * Reserve contexts.
 271  *
 272  * \param inode device inode.
 273  * \param file_priv DRM file private.
 274  * \param cmd command.
 275  * \param arg user argument pointing to a drm_ctx_res structure.
 276  * \return zero on success or a negative number on failure.
 277  */
 278 int drm_resctx(struct drm_device *dev, void *data,
 279                struct drm_file *file_priv)
 280 {
 281         struct drm_ctx_res *res = data;
 282         struct drm_ctx ctx;
 283         int i;
 284
 285         if (res->count >= DRM_RESERVED_CONTEXTS) {
 286                 memset(&ctx, 0, sizeof(ctx));
 287                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 288                         ctx.handle = i;
 289                         if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
 290                                 return -EFAULT;
 291                 }
 292         }
 293         res->count = DRM_RESERVED_CONTEXTS;
 294
 295         return 0;
 296 }
 297
 298 /**
 299  * Add context.
 300  *
 301  * \param inode device inode.
 302  * \param file_priv DRM file private.
 303  * \param cmd command.
 304  * \param arg user argument pointing to a drm_ctx structure.
 305  * \return zero on success or a negative number on failure.
 306  *
 307  * Get a new handle for the context and copy to userspace.
 308  */
 309 int drm_addctx(struct drm_device *dev, void *data,
 310                struct drm_file *file_priv)
 311 {
 312         struct drm_ctx_list *ctx_entry;
 313         struct drm_ctx *ctx = data;
 314
 315         ctx->handle = drm_ctxbitmap_next(dev);
 316         if (ctx->handle == DRM_KERNEL_CONTEXT) {
 317                 /* Skip kernel's context and get a new one. */
 318                 ctx->handle = drm_ctxbitmap_next(dev);
 319         }
 320         DRM_DEBUG("%d\n", ctx->handle);
 321         if (ctx->handle == -1) {
 322                 DRM_DEBUG("Not enough free contexts.\n");
 323                 /* Should this return -EBUSY instead? */
 324                 return -ENOMEM;
 325         }
 326
 327         ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
 328         if (!ctx_entry) {
 329                 DRM_DEBUG("out of memory\n");
 330                 return -ENOMEM;
 331         }
 332
 333         INIT_LIST_HEAD(&ctx_entry->head);
 334         ctx_entry->handle = ctx->handle;
 335         ctx_entry->tag = file_priv;
 336
 337         mutex_lock(&dev->ctxlist_mutex);
 338         list_add(&ctx_entry->head, &dev->ctxlist);
 339         ++dev->ctx_count;
 340         mutex_unlock(&dev->ctxlist_mutex);
 341
 342         return 0;
 343 }
 344
 345 int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 346 {
 347         /* This does nothing */
 348         return 0;
 349 }
 350
 351 /**
 352  * Get context.
 353  *
 354  * \param inode device inode.
 355  * \param file_priv DRM file private.
 356  * \param cmd command.
 357  * \param arg user argument pointing to a drm_ctx structure.
 358  * \return zero on success or a negative number on failure.
 359  */
 360 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 361 {
 362         struct drm_ctx *ctx = data;
 363
 364         /* This is 0, because we don't handle any context flags */
 365         ctx->flags = 0;
 366
 367         return 0;
 368 }
 369
 370 /**
 371  * Switch context.
 372  *
 373  * \param inode device inode.
 374  * \param file_priv DRM file private.
 375  * \param cmd command.
 376  * \param arg user argument pointing to a drm_ctx structure.
 377  * \return zero on success or a negative number on failure.
 378  *
 379  * Calls context_switch().
 380  */
 381 int drm_switchctx(struct drm_device *dev, void *data,
 382                   struct drm_file *file_priv)
 383 {
 384         struct drm_ctx *ctx = data;
 385
 386         DRM_DEBUG("%d\n", ctx->handle);
 387         return drm_context_switch(dev, dev->last_context, ctx->handle);
 388 }
 389
 390 /**
 391  * New context.
 392  *
 393  * \param inode device inode.
 394  * \param file_priv DRM file private.
 395  * \param cmd command.
 396  * \param arg user argument pointing to a drm_ctx structure.
 397  * \return zero on success or a negative number on failure.
 398  *
 399  * Calls context_switch_complete().
 400  */
 401 int drm_newctx(struct drm_device *dev, void *data,
 402                struct drm_file *file_priv)
 403 {
 404         struct drm_ctx *ctx = data;
 405
 406         DRM_DEBUG("%d\n", ctx->handle);
 407         drm_context_switch_complete(dev, file_priv, ctx->handle);
 408
 409         return 0;
 410 }
 411
 412 /**
 413  * Remove context.
 414  *
 415  * \param inode device inode.
 416  * \param file_priv DRM file private.
 417  * \param cmd command.
 418  * \param arg user argument pointing to a drm_ctx structure.
 419  * \return zero on success or a negative number on failure.
 420  *
 421  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 422  */
 423 int drm_rmctx(struct drm_device *dev, void *data,
 424               struct drm_file *file_priv)
 425 {
 426         struct drm_ctx *ctx = data;
 427
 428         DRM_DEBUG("%d\n", ctx->handle);
 429         if (ctx->handle != DRM_KERNEL_CONTEXT) {
 430                 if (dev->driver->context_dtor)
 431                         dev->driver->context_dtor(dev, ctx->handle);
 432                 drm_ctxbitmap_free(dev, ctx->handle);
 433         }
 434
 435         mutex_lock(&dev->ctxlist_mutex);
 436         if (!list_empty(&dev->ctxlist)) {
 437                 struct drm_ctx_list *pos, *n;
 438
 439                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 440                         if (pos->handle == ctx->handle) {
 441                                 list_del(&pos->head);
 442                                 kfree(pos);
 443                                 --dev->ctx_count;
 444                         }
 445                 }
 446         }
 447         mutex_unlock(&dev->ctxlist_mutex);
 448
 449         return 0;
 450 }
 451
 452 /*@}*/