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 new_id;
  78         int ret;
  79
  80 again:
  81         if (idr_pre_get(&dev->ctx_idr, GFP_KERNEL) == 0) {
  82                 DRM_ERROR("Out of memory expanding drawable idr\n");
  83                 return -ENOMEM;
  84         }
  85         mutex_lock(&dev->struct_mutex);
  86         ret = idr_get_new_above(&dev->ctx_idr, NULL,
  87                                 DRM_RESERVED_CONTEXTS, &new_id);
  88         mutex_unlock(&dev->struct_mutex);
  89         if (ret == -EAGAIN)
  90                 goto again;
  91         else if (ret)
  92                 return ret;
  93
  94         return new_id;
  95 }
  96
  97 /**
  98  * Context bitmap initialization.
  99  *
 100  * \param dev DRM device.
 101  *
 102  * Initialise the drm_device::ctx_idr
 103  */
 104 int drm_ctxbitmap_init(struct drm_device * dev)
 105 {
 106         idr_init(&dev->ctx_idr);
 107         return 0;
 108 }
 109
 110 /**
 111  * Context bitmap cleanup.
 112  *
 113  * \param dev DRM device.
 114  *
 115  * Free all idr members using drm_ctx_sarea_free helper function
 116  * while holding the drm_device::struct_mutex lock.
 117  */
 118 void drm_ctxbitmap_cleanup(struct drm_device * dev)
 119 {
 120         mutex_lock(&dev->struct_mutex);
 121         idr_remove_all(&dev->ctx_idr);
 122         mutex_unlock(&dev->struct_mutex);
 123 }
 124
 125 /*@}*/
 126
 127 /******************************************************************/
 128 /** \name Per Context SAREA Support */
 129 /*@{*/
 130
 131 /**
 132  * Get per-context SAREA.
 133  *
 134  * \param inode device inode.
 135  * \param file_priv DRM file private.
 136  * \param cmd command.
 137  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 138  * \return zero on success or a negative number on failure.
 139  *
 140  * Gets the map from drm_device::ctx_idr with the handle specified and
 141  * returns its handle.
 142  */
 143 int drm_getsareactx(struct drm_device *dev, void *data,
 144                     struct drm_file *file_priv)
 145 {
 146         struct drm_ctx_priv_map *request = data;
 147         struct drm_local_map *map;
 148         struct drm_map_list *_entry;
 149
 150         mutex_lock(&dev->struct_mutex);
 151
 152         map = idr_find(&dev->ctx_idr, request->ctx_id);
 153         if (!map) {
 154                 mutex_unlock(&dev->struct_mutex);
 155                 return -EINVAL;
 156         }
 157
 158         request->handle = NULL;
 159         list_for_each_entry(_entry, &dev->maplist, head) {
 160                 if (_entry->map == map) {
 161                         request->handle =
 162                             (void *)(unsigned long)_entry->user_token;
 163                         break;
 164                 }
 165         }
 166
 167         mutex_unlock(&dev->struct_mutex);
 168
 169         if (request->handle == NULL)
 170                 return -EINVAL;
 171
 172         return 0;
 173 }
 174
 175 /**
 176  * Set per-context SAREA.
 177  *
 178  * \param inode device inode.
 179  * \param file_priv DRM file private.
 180  * \param cmd command.
 181  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 182  * \return zero on success or a negative number on failure.
 183  *
 184  * Searches the mapping specified in \p arg and update the entry in
 185  * drm_device::ctx_idr with it.
 186  */
 187 int drm_setsareactx(struct drm_device *dev, void *data,
 188                     struct drm_file *file_priv)
 189 {
 190         struct drm_ctx_priv_map *request = data;
 191         struct drm_local_map *map = NULL;
 192         struct drm_map_list *r_list = NULL;
 193
 194         mutex_lock(&dev->struct_mutex);
 195         list_for_each_entry(r_list, &dev->maplist, head) {
 196                 if (r_list->map
 197                     && r_list->user_token == (unsigned long) request->handle)
 198                         goto found;
 199         }
 200       bad:
 201         mutex_unlock(&dev->struct_mutex);
 202         return -EINVAL;
 203
 204       found:
 205         map = r_list->map;
 206         if (!map)
 207                 goto bad;
 208
 209         if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
 210                 goto bad;
 211
 212         mutex_unlock(&dev->struct_mutex);
 213
 214         return 0;
 215 }
 216
 217 /*@}*/
 218
 219 /******************************************************************/
 220 /** \name The actual DRM context handling routines */
 221 /*@{*/
 222
 223 /**
 224  * Switch context.
 225  *
 226  * \param dev DRM device.
 227  * \param old old context handle.
 228  * \param new new context handle.
 229  * \return zero on success or a negative number on failure.
 230  *
 231  * Attempt to set drm_device::context_flag.
 232  */
 233 static int drm_context_switch(struct drm_device * dev, int old, int new)
 234 {
 235         if (test_and_set_bit(0, &dev->context_flag)) {
 236                 DRM_ERROR("Reentering -- FIXME\n");
 237                 return -EBUSY;
 238         }
 239
 240         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 241
 242         if (new == dev->last_context) {
 243                 clear_bit(0, &dev->context_flag);
 244                 return 0;
 245         }
 246
 247         return 0;
 248 }
 249
 250 /**
 251  * Complete context switch.
 252  *
 253  * \param dev DRM device.
 254  * \param new new context handle.
 255  * \return zero on success or a negative number on failure.
 256  *
 257  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 258  * hardware lock is held, clears the drm_device::context_flag and wakes up
 259  * drm_device::context_wait.
 260  */
 261 static int drm_context_switch_complete(struct drm_device *dev,
 262                                        struct drm_file *file_priv, int new)
 263 {
 264         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 265         dev->last_switch = jiffies;
 266
 267         if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 268                 DRM_ERROR("Lock isn't held after context switch\n");
 269         }
 270
 271         /* If a context switch is ever initiated
 272            when the kernel holds the lock, release
 273            that lock here. */
 274         clear_bit(0, &dev->context_flag);
 275         wake_up(&dev->context_wait);
 276
 277         return 0;
 278 }
 279
 280 /**
 281  * Reserve contexts.
 282  *
 283  * \param inode device inode.
 284  * \param file_priv DRM file private.
 285  * \param cmd command.
 286  * \param arg user argument pointing to a drm_ctx_res structure.
 287  * \return zero on success or a negative number on failure.
 288  */
 289 int drm_resctx(struct drm_device *dev, void *data,
 290                struct drm_file *file_priv)
 291 {
 292         struct drm_ctx_res *res = data;
 293         struct drm_ctx ctx;
 294         int i;
 295
 296         if (res->count >= DRM_RESERVED_CONTEXTS) {
 297                 memset(&ctx, 0, sizeof(ctx));
 298                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 299                         ctx.handle = i;
 300                         if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
 301                                 return -EFAULT;
 302                 }
 303         }
 304         res->count = DRM_RESERVED_CONTEXTS;
 305
 306         return 0;
 307 }
 308
 309 /**
 310  * Add context.
 311  *
 312  * \param inode device inode.
 313  * \param file_priv DRM file private.
 314  * \param cmd command.
 315  * \param arg user argument pointing to a drm_ctx structure.
 316  * \return zero on success or a negative number on failure.
 317  *
 318  * Get a new handle for the context and copy to userspace.
 319  */
 320 int drm_addctx(struct drm_device *dev, void *data,
 321                struct drm_file *file_priv)
 322 {
 323         struct drm_ctx_list *ctx_entry;
 324         struct drm_ctx *ctx = data;
 325
 326         ctx->handle = drm_ctxbitmap_next(dev);
 327         if (ctx->handle == DRM_KERNEL_CONTEXT) {
 328                 /* Skip kernel's context and get a new one. */
 329                 ctx->handle = drm_ctxbitmap_next(dev);
 330         }
 331         DRM_DEBUG("%d\n", ctx->handle);
 332         if (ctx->handle == -1) {
 333                 DRM_DEBUG("Not enough free contexts.\n");
 334                 /* Should this return -EBUSY instead? */
 335                 return -ENOMEM;
 336         }
 337
 338         ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
 339         if (!ctx_entry) {
 340                 DRM_DEBUG("out of memory\n");
 341                 return -ENOMEM;
 342         }
 343
 344         INIT_LIST_HEAD(&ctx_entry->head);
 345         ctx_entry->handle = ctx->handle;
 346         ctx_entry->tag = file_priv;
 347
 348         mutex_lock(&dev->ctxlist_mutex);
 349         list_add(&ctx_entry->head, &dev->ctxlist);
 350         ++dev->ctx_count;
 351         mutex_unlock(&dev->ctxlist_mutex);
 352
 353         return 0;
 354 }
 355
 356 int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 357 {
 358         /* This does nothing */
 359         return 0;
 360 }
 361
 362 /**
 363  * Get 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 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 372 {
 373         struct drm_ctx *ctx = data;
 374
 375         /* This is 0, because we don't handle any context flags */
 376         ctx->flags = 0;
 377
 378         return 0;
 379 }
 380
 381 /**
 382  * Switch context.
 383  *
 384  * \param inode device inode.
 385  * \param file_priv DRM file private.
 386  * \param cmd command.
 387  * \param arg user argument pointing to a drm_ctx structure.
 388  * \return zero on success or a negative number on failure.
 389  *
 390  * Calls context_switch().
 391  */
 392 int drm_switchctx(struct drm_device *dev, void *data,
 393                   struct drm_file *file_priv)
 394 {
 395         struct drm_ctx *ctx = data;
 396
 397         DRM_DEBUG("%d\n", ctx->handle);
 398         return drm_context_switch(dev, dev->last_context, ctx->handle);
 399 }
 400
 401 /**
 402  * New context.
 403  *
 404  * \param inode device inode.
 405  * \param file_priv DRM file private.
 406  * \param cmd command.
 407  * \param arg user argument pointing to a drm_ctx structure.
 408  * \return zero on success or a negative number on failure.
 409  *
 410  * Calls context_switch_complete().
 411  */
 412 int drm_newctx(struct drm_device *dev, void *data,
 413                struct drm_file *file_priv)
 414 {
 415         struct drm_ctx *ctx = data;
 416
 417         DRM_DEBUG("%d\n", ctx->handle);
 418         drm_context_switch_complete(dev, file_priv, ctx->handle);
 419
 420         return 0;
 421 }
 422
 423 /**
 424  * Remove context.
 425  *
 426  * \param inode device inode.
 427  * \param file_priv DRM file private.
 428  * \param cmd command.
 429  * \param arg user argument pointing to a drm_ctx structure.
 430  * \return zero on success or a negative number on failure.
 431  *
 432  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 433  */
 434 int drm_rmctx(struct drm_device *dev, void *data,
 435               struct drm_file *file_priv)
 436 {
 437         struct drm_ctx *ctx = data;
 438
 439         DRM_DEBUG("%d\n", ctx->handle);
 440         if (ctx->handle != DRM_KERNEL_CONTEXT) {
 441                 if (dev->driver->context_dtor)
 442                         dev->driver->context_dtor(dev, ctx->handle);
 443                 drm_ctxbitmap_free(dev, ctx->handle);
 444         }
 445
 446         mutex_lock(&dev->ctxlist_mutex);
 447         if (!list_empty(&dev->ctxlist)) {
 448                 struct drm_ctx_list *pos, *n;
 449
 450                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 451                         if (pos->handle == ctx->handle) {
 452                                 list_del(&pos->head);
 453                                 kfree(pos);
 454                                 --dev->ctx_count;
 455                         }
 456                 }
 457         }
 458         mutex_unlock(&dev->ctxlist_mutex);
 459
 460         return 0;
 461 }
 462
 463 /*@}*/