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 "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         if (ret == -EAGAIN) {
  89                 mutex_unlock(&dev->struct_mutex);
  90                 goto again;
  91         }
  92         mutex_unlock(&dev->struct_mutex);
  93         return new_id;
  94 }
  95
  96 /**
  97  * Context bitmap initialization.
  98  *
  99  * \param dev DRM device.
 100  *
 101  * Initialise the drm_device::ctx_idr
 102  */
 103 int drm_ctxbitmap_init(struct drm_device * dev)
 104 {
 105         idr_init(&dev->ctx_idr);
 106         return 0;
 107 }
 108
 109 /**
 110  * Context bitmap cleanup.
 111  *
 112  * \param dev DRM device.
 113  *
 114  * Free all idr members using drm_ctx_sarea_free helper function
 115  * while holding the drm_device::struct_mutex lock.
 116  */
 117 void drm_ctxbitmap_cleanup(struct drm_device * dev)
 118 {
 119         mutex_lock(&dev->struct_mutex);
 120         idr_remove_all(&dev->ctx_idr);
 121         mutex_unlock(&dev->struct_mutex);
 122 }
 123
 124 /*@}*/
 125
 126 /******************************************************************/
 127 /** \name Per Context SAREA Support */
 128 /*@{*/
 129
 130 /**
 131  * Get per-context SAREA.
 132  *
 133  * \param inode device inode.
 134  * \param file_priv DRM file private.
 135  * \param cmd command.
 136  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 137  * \return zero on success or a negative number on failure.
 138  *
 139  * Gets the map from drm_device::ctx_idr with the handle specified and
 140  * returns its handle.
 141  */
 142 int drm_getsareactx(struct drm_device *dev, void *data,
 143                     struct drm_file *file_priv)
 144 {
 145         struct drm_ctx_priv_map *request = data;
 146         struct drm_local_map *map;
 147         struct drm_map_list *_entry;
 148
 149         mutex_lock(&dev->struct_mutex);
 150
 151         map = idr_find(&dev->ctx_idr, request->ctx_id);
 152         if (!map) {
 153                 mutex_unlock(&dev->struct_mutex);
 154                 return -EINVAL;
 155         }
 156
 157         mutex_unlock(&dev->struct_mutex);
 158
 159         request->handle = NULL;
 160         list_for_each_entry(_entry, &dev->maplist, head) {
 161                 if (_entry->map == map) {
 162                         request->handle =
 163                             (void *)(unsigned long)_entry->user_token;
 164                         break;
 165                 }
 166         }
 167         if (request->handle == NULL)
 168                 return -EINVAL;
 169
 170         return 0;
 171 }
 172
 173 /**
 174  * Set per-context SAREA.
 175  *
 176  * \param inode device inode.
 177  * \param file_priv DRM file private.
 178  * \param cmd command.
 179  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 180  * \return zero on success or a negative number on failure.
 181  *
 182  * Searches the mapping specified in \p arg and update the entry in
 183  * drm_device::ctx_idr with it.
 184  */
 185 int drm_setsareactx(struct drm_device *dev, void *data,
 186                     struct drm_file *file_priv)
 187 {
 188         struct drm_ctx_priv_map *request = data;
 189         struct drm_local_map *map = NULL;
 190         struct drm_map_list *r_list = NULL;
 191
 192         mutex_lock(&dev->struct_mutex);
 193         list_for_each_entry(r_list, &dev->maplist, head) {
 194                 if (r_list->map
 195                     && r_list->user_token == (unsigned long) request->handle)
 196                         goto found;
 197         }
 198       bad:
 199         mutex_unlock(&dev->struct_mutex);
 200         return -EINVAL;
 201
 202       found:
 203         map = r_list->map;
 204         if (!map)
 205                 goto bad;
 206
 207         if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
 208                 goto bad;
 209
 210         mutex_unlock(&dev->struct_mutex);
 211
 212         return 0;
 213 }
 214
 215 /*@}*/
 216
 217 /******************************************************************/
 218 /** \name The actual DRM context handling routines */
 219 /*@{*/
 220
 221 /**
 222  * Switch context.
 223  *
 224  * \param dev DRM device.
 225  * \param old old context handle.
 226  * \param new new context handle.
 227  * \return zero on success or a negative number on failure.
 228  *
 229  * Attempt to set drm_device::context_flag.
 230  */
 231 static int drm_context_switch(struct drm_device * dev, int old, int new)
 232 {
 233         if (test_and_set_bit(0, &dev->context_flag)) {
 234                 DRM_ERROR("Reentering -- FIXME\n");
 235                 return -EBUSY;
 236         }
 237
 238         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 239
 240         if (new == dev->last_context) {
 241                 clear_bit(0, &dev->context_flag);
 242                 return 0;
 243         }
 244
 245         return 0;
 246 }
 247
 248 /**
 249  * Complete context switch.
 250  *
 251  * \param dev DRM device.
 252  * \param new new context handle.
 253  * \return zero on success or a negative number on failure.
 254  *
 255  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 256  * hardware lock is held, clears the drm_device::context_flag and wakes up
 257  * drm_device::context_wait.
 258  */
 259 static int drm_context_switch_complete(struct drm_device *dev,
 260                                        struct drm_file *file_priv, int new)
 261 {
 262         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 263         dev->last_switch = jiffies;
 264
 265         if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 266                 DRM_ERROR("Lock isn't held after context switch\n");
 267         }
 268
 269         /* If a context switch is ever initiated
 270            when the kernel holds the lock, release
 271            that lock here. */
 272         clear_bit(0, &dev->context_flag);
 273         wake_up(&dev->context_wait);
 274
 275         return 0;
 276 }
 277
 278 /**
 279  * Reserve contexts.
 280  *
 281  * \param inode device inode.
 282  * \param file_priv DRM file private.
 283  * \param cmd command.
 284  * \param arg user argument pointing to a drm_ctx_res structure.
 285  * \return zero on success or a negative number on failure.
 286  */
 287 int drm_resctx(struct drm_device *dev, void *data,
 288                struct drm_file *file_priv)
 289 {
 290         struct drm_ctx_res *res = data;
 291         struct drm_ctx ctx;
 292         int i;
 293
 294         if (res->count >= DRM_RESERVED_CONTEXTS) {
 295                 memset(&ctx, 0, sizeof(ctx));
 296                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 297                         ctx.handle = i;
 298                         if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
 299                                 return -EFAULT;
 300                 }
 301         }
 302         res->count = DRM_RESERVED_CONTEXTS;
 303
 304         return 0;
 305 }
 306
 307 /**
 308  * Add context.
 309  *
 310  * \param inode device inode.
 311  * \param file_priv DRM file private.
 312  * \param cmd command.
 313  * \param arg user argument pointing to a drm_ctx structure.
 314  * \return zero on success or a negative number on failure.
 315  *
 316  * Get a new handle for the context and copy to userspace.
 317  */
 318 int drm_addctx(struct drm_device *dev, void *data,
 319                struct drm_file *file_priv)
 320 {
 321         struct drm_ctx_list *ctx_entry;
 322         struct drm_ctx *ctx = data;
 323
 324         ctx->handle = drm_ctxbitmap_next(dev);
 325         if (ctx->handle == DRM_KERNEL_CONTEXT) {
 326                 /* Skip kernel's context and get a new one. */
 327                 ctx->handle = drm_ctxbitmap_next(dev);
 328         }
 329         DRM_DEBUG("%d\n", ctx->handle);
 330         if (ctx->handle == -1) {
 331                 DRM_DEBUG("Not enough free contexts.\n");
 332                 /* Should this return -EBUSY instead? */
 333                 return -ENOMEM;
 334         }
 335
 336         ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
 337         if (!ctx_entry) {
 338                 DRM_DEBUG("out of memory\n");
 339                 return -ENOMEM;
 340         }
 341
 342         INIT_LIST_HEAD(&ctx_entry->head);
 343         ctx_entry->handle = ctx->handle;
 344         ctx_entry->tag = file_priv;
 345
 346         mutex_lock(&dev->ctxlist_mutex);
 347         list_add(&ctx_entry->head, &dev->ctxlist);
 348         ++dev->ctx_count;
 349         mutex_unlock(&dev->ctxlist_mutex);
 350
 351         return 0;
 352 }
 353
 354 int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 355 {
 356         /* This does nothing */
 357         return 0;
 358 }
 359
 360 /**
 361  * Get context.
 362  *
 363  * \param inode device inode.
 364  * \param file_priv DRM file private.
 365  * \param cmd command.
 366  * \param arg user argument pointing to a drm_ctx structure.
 367  * \return zero on success or a negative number on failure.
 368  */
 369 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 370 {
 371         struct drm_ctx *ctx = data;
 372
 373         /* This is 0, because we don't handle any context flags */
 374         ctx->flags = 0;
 375
 376         return 0;
 377 }
 378
 379 /**
 380  * Switch context.
 381  *
 382  * \param inode device inode.
 383  * \param file_priv DRM file private.
 384  * \param cmd command.
 385  * \param arg user argument pointing to a drm_ctx structure.
 386  * \return zero on success or a negative number on failure.
 387  *
 388  * Calls context_switch().
 389  */
 390 int drm_switchctx(struct drm_device *dev, void *data,
 391                   struct drm_file *file_priv)
 392 {
 393         struct drm_ctx *ctx = data;
 394
 395         DRM_DEBUG("%d\n", ctx->handle);
 396         return drm_context_switch(dev, dev->last_context, ctx->handle);
 397 }
 398
 399 /**
 400  * New context.
 401  *
 402  * \param inode device inode.
 403  * \param file_priv DRM file private.
 404  * \param cmd command.
 405  * \param arg user argument pointing to a drm_ctx structure.
 406  * \return zero on success or a negative number on failure.
 407  *
 408  * Calls context_switch_complete().
 409  */
 410 int drm_newctx(struct drm_device *dev, void *data,
 411                struct drm_file *file_priv)
 412 {
 413         struct drm_ctx *ctx = data;
 414
 415         DRM_DEBUG("%d\n", ctx->handle);
 416         drm_context_switch_complete(dev, file_priv, ctx->handle);
 417
 418         return 0;
 419 }
 420
 421 /**
 422  * Remove context.
 423  *
 424  * \param inode device inode.
 425  * \param file_priv DRM file private.
 426  * \param cmd command.
 427  * \param arg user argument pointing to a drm_ctx structure.
 428  * \return zero on success or a negative number on failure.
 429  *
 430  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 431  */
 432 int drm_rmctx(struct drm_device *dev, void *data,
 433               struct drm_file *file_priv)
 434 {
 435         struct drm_ctx *ctx = data;
 436
 437         DRM_DEBUG("%d\n", ctx->handle);
 438         if (ctx->handle != DRM_KERNEL_CONTEXT) {
 439                 if (dev->driver->context_dtor)
 440                         dev->driver->context_dtor(dev, ctx->handle);
 441                 drm_ctxbitmap_free(dev, ctx->handle);
 442         }
 443
 444         mutex_lock(&dev->ctxlist_mutex);
 445         if (!list_empty(&dev->ctxlist)) {
 446                 struct drm_ctx_list *pos, *n;
 447
 448                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 449                         if (pos->handle == ctx->handle) {
 450                                 list_del(&pos->head);
 451                                 kfree(pos);
 452                                 --dev->ctx_count;
 453                         }
 454                 }
 455         }
 456         mutex_unlock(&dev->ctxlist_mutex);
 457
 458         return 0;
 459 }
 460
 461 /*@}*/