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
 255         if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 256                 DRM_ERROR("Lock isn't held after context switch\n");
 257         }
 258
 259         /* If a context switch is ever initiated
 260            when the kernel holds the lock, release
 261            that lock here. */
 262         clear_bit(0, &dev->context_flag);
 263
 264         return 0;
 265 }
 266
 267 /**
 268  * Reserve contexts.
 269  *
 270  * \param inode device inode.
 271  * \param file_priv DRM file private.
 272  * \param cmd command.
 273  * \param arg user argument pointing to a drm_ctx_res structure.
 274  * \return zero on success or a negative number on failure.
 275  */
 276 int drm_resctx(struct drm_device *dev, void *data,
 277                struct drm_file *file_priv)
 278 {
 279         struct drm_ctx_res *res = data;
 280         struct drm_ctx ctx;
 281         int i;
 282
 283         if (res->count >= DRM_RESERVED_CONTEXTS) {
 284                 memset(&ctx, 0, sizeof(ctx));
 285                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 286                         ctx.handle = i;
 287                         if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
 288                                 return -EFAULT;
 289                 }
 290         }
 291         res->count = DRM_RESERVED_CONTEXTS;
 292
 293         return 0;
 294 }
 295
 296 /**
 297  * Add context.
 298  *
 299  * \param inode device inode.
 300  * \param file_priv DRM file private.
 301  * \param cmd command.
 302  * \param arg user argument pointing to a drm_ctx structure.
 303  * \return zero on success or a negative number on failure.
 304  *
 305  * Get a new handle for the context and copy to userspace.
 306  */
 307 int drm_addctx(struct drm_device *dev, void *data,
 308                struct drm_file *file_priv)
 309 {
 310         struct drm_ctx_list *ctx_entry;
 311         struct drm_ctx *ctx = data;
 312
 313         ctx->handle = drm_ctxbitmap_next(dev);
 314         if (ctx->handle == DRM_KERNEL_CONTEXT) {
 315                 /* Skip kernel's context and get a new one. */
 316                 ctx->handle = drm_ctxbitmap_next(dev);
 317         }
 318         DRM_DEBUG("%d\n", ctx->handle);
 319         if (ctx->handle == -1) {
 320                 DRM_DEBUG("Not enough free contexts.\n");
 321                 /* Should this return -EBUSY instead? */
 322                 return -ENOMEM;
 323         }
 324
 325         ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
 326         if (!ctx_entry) {
 327                 DRM_DEBUG("out of memory\n");
 328                 return -ENOMEM;
 329         }
 330
 331         INIT_LIST_HEAD(&ctx_entry->head);
 332         ctx_entry->handle = ctx->handle;
 333         ctx_entry->tag = file_priv;
 334
 335         mutex_lock(&dev->ctxlist_mutex);
 336         list_add(&ctx_entry->head, &dev->ctxlist);
 337         ++dev->ctx_count;
 338         mutex_unlock(&dev->ctxlist_mutex);
 339
 340         return 0;
 341 }
 342
 343 /**
 344  * Get context.
 345  *
 346  * \param inode device inode.
 347  * \param file_priv DRM file private.
 348  * \param cmd command.
 349  * \param arg user argument pointing to a drm_ctx structure.
 350  * \return zero on success or a negative number on failure.
 351  */
 352 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 353 {
 354         struct drm_ctx *ctx = data;
 355
 356         /* This is 0, because we don't handle any context flags */
 357         ctx->flags = 0;
 358
 359         return 0;
 360 }
 361
 362 /**
 363  * Switch context.
 364  *
 365  * \param inode device inode.
 366  * \param file_priv DRM file private.
 367  * \param cmd command.
 368  * \param arg user argument pointing to a drm_ctx structure.
 369  * \return zero on success or a negative number on failure.
 370  *
 371  * Calls context_switch().
 372  */
 373 int drm_switchctx(struct drm_device *dev, void *data,
 374                   struct drm_file *file_priv)
 375 {
 376         struct drm_ctx *ctx = data;
 377
 378         DRM_DEBUG("%d\n", ctx->handle);
 379         return drm_context_switch(dev, dev->last_context, ctx->handle);
 380 }
 381
 382 /**
 383  * New context.
 384  *
 385  * \param inode device inode.
 386  * \param file_priv DRM file private.
 387  * \param cmd command.
 388  * \param arg user argument pointing to a drm_ctx structure.
 389  * \return zero on success or a negative number on failure.
 390  *
 391  * Calls context_switch_complete().
 392  */
 393 int drm_newctx(struct drm_device *dev, void *data,
 394                struct drm_file *file_priv)
 395 {
 396         struct drm_ctx *ctx = data;
 397
 398         DRM_DEBUG("%d\n", ctx->handle);
 399         drm_context_switch_complete(dev, file_priv, ctx->handle);
 400
 401         return 0;
 402 }
 403
 404 /**
 405  * Remove context.
 406  *
 407  * \param inode device inode.
 408  * \param file_priv DRM file private.
 409  * \param cmd command.
 410  * \param arg user argument pointing to a drm_ctx structure.
 411  * \return zero on success or a negative number on failure.
 412  *
 413  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 414  */
 415 int drm_rmctx(struct drm_device *dev, void *data,
 416               struct drm_file *file_priv)
 417 {
 418         struct drm_ctx *ctx = data;
 419
 420         DRM_DEBUG("%d\n", ctx->handle);
 421         if (ctx->handle != DRM_KERNEL_CONTEXT) {
 422                 if (dev->driver->context_dtor)
 423                         dev->driver->context_dtor(dev, ctx->handle);
 424                 drm_ctxbitmap_free(dev, ctx->handle);
 425         }
 426
 427         mutex_lock(&dev->ctxlist_mutex);
 428         if (!list_empty(&dev->ctxlist)) {
 429                 struct drm_ctx_list *pos, *n;
 430
 431                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 432                         if (pos->handle == ctx->handle) {
 433                                 list_del(&pos->head);
 434                                 kfree(pos);
 435                                 --dev->ctx_count;
 436                         }
 437                 }
 438         }
 439         mutex_unlock(&dev->ctxlist_mutex);
 440
 441         return 0;
 442 }
 443
 444 /*@}*/