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         request->handle = NULL;
 158         list_for_each_entry(_entry, &dev->maplist, head) {
 159                 if (_entry->map == map) {
 160                         request->handle =
 161                             (void *)(unsigned long)_entry->user_token;
 162                         break;
 163                 }
 164         }
 165
 166         mutex_unlock(&dev->struct_mutex);
 167
 168         if (request->handle == NULL)
 169                 return -EINVAL;
 170
 171         return 0;
 172 }
 173
 174 /**
 175  * Set per-context SAREA.
 176  *
 177  * \param inode device inode.
 178  * \param file_priv DRM file private.
 179  * \param cmd command.
 180  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 181  * \return zero on success or a negative number on failure.
 182  *
 183  * Searches the mapping specified in \p arg and update the entry in
 184  * drm_device::ctx_idr with it.
 185  */
 186 int drm_setsareactx(struct drm_device *dev, void *data,
 187                     struct drm_file *file_priv)
 188 {
 189         struct drm_ctx_priv_map *request = data;
 190         struct drm_local_map *map = NULL;
 191         struct drm_map_list *r_list = NULL;
 192
 193         mutex_lock(&dev->struct_mutex);
 194         list_for_each_entry(r_list, &dev->maplist, head) {
 195                 if (r_list->map
 196                     && r_list->user_token == (unsigned long) request->handle)
 197                         goto found;
 198         }
 199       bad:
 200         mutex_unlock(&dev->struct_mutex);
 201         return -EINVAL;
 202
 203       found:
 204         map = r_list->map;
 205         if (!map)
 206                 goto bad;
 207
 208         if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
 209                 goto bad;
 210
 211         mutex_unlock(&dev->struct_mutex);
 212
 213         return 0;
 214 }
 215
 216 /*@}*/
 217
 218 /******************************************************************/
 219 /** \name The actual DRM context handling routines */
 220 /*@{*/
 221
 222 /**
 223  * Switch context.
 224  *
 225  * \param dev DRM device.
 226  * \param old old context handle.
 227  * \param new new context handle.
 228  * \return zero on success or a negative number on failure.
 229  *
 230  * Attempt to set drm_device::context_flag.
 231  */
 232 static int drm_context_switch(struct drm_device * dev, int old, int new)
 233 {
 234         if (test_and_set_bit(0, &dev->context_flag)) {
 235                 DRM_ERROR("Reentering -- FIXME\n");
 236                 return -EBUSY;
 237         }
 238
 239         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 240
 241         if (new == dev->last_context) {
 242                 clear_bit(0, &dev->context_flag);
 243                 return 0;
 244         }
 245
 246         return 0;
 247 }
 248
 249 /**
 250  * Complete context switch.
 251  *
 252  * \param dev DRM device.
 253  * \param new new context handle.
 254  * \return zero on success or a negative number on failure.
 255  *
 256  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 257  * hardware lock is held, clears the drm_device::context_flag and wakes up
 258  * drm_device::context_wait.
 259  */
 260 static int drm_context_switch_complete(struct drm_device *dev,
 261                                        struct drm_file *file_priv, int new)
 262 {
 263         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 264         dev->last_switch = jiffies;
 265
 266         if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 267                 DRM_ERROR("Lock isn't held after context switch\n");
 268         }
 269
 270         /* If a context switch is ever initiated
 271            when the kernel holds the lock, release
 272            that lock here. */
 273         clear_bit(0, &dev->context_flag);
 274         wake_up(&dev->context_wait);
 275
 276         return 0;
 277 }
 278
 279 /**
 280  * Reserve contexts.
 281  *
 282  * \param inode device inode.
 283  * \param file_priv DRM file private.
 284  * \param cmd command.
 285  * \param arg user argument pointing to a drm_ctx_res structure.
 286  * \return zero on success or a negative number on failure.
 287  */
 288 int drm_resctx(struct drm_device *dev, void *data,
 289                struct drm_file *file_priv)
 290 {
 291         struct drm_ctx_res *res = data;
 292         struct drm_ctx ctx;
 293         int i;
 294
 295         if (res->count >= DRM_RESERVED_CONTEXTS) {
 296                 memset(&ctx, 0, sizeof(ctx));
 297                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 298                         ctx.handle = i;
 299                         if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
 300                                 return -EFAULT;
 301                 }
 302         }
 303         res->count = DRM_RESERVED_CONTEXTS;
 304
 305         return 0;
 306 }
 307
 308 /**
 309  * Add context.
 310  *
 311  * \param inode device inode.
 312  * \param file_priv DRM file private.
 313  * \param cmd command.
 314  * \param arg user argument pointing to a drm_ctx structure.
 315  * \return zero on success or a negative number on failure.
 316  *
 317  * Get a new handle for the context and copy to userspace.
 318  */
 319 int drm_addctx(struct drm_device *dev, void *data,
 320                struct drm_file *file_priv)
 321 {
 322         struct drm_ctx_list *ctx_entry;
 323         struct drm_ctx *ctx = data;
 324
 325         ctx->handle = drm_ctxbitmap_next(dev);
 326         if (ctx->handle == DRM_KERNEL_CONTEXT) {
 327                 /* Skip kernel's context and get a new one. */
 328                 ctx->handle = drm_ctxbitmap_next(dev);
 329         }
 330         DRM_DEBUG("%d\n", ctx->handle);
 331         if (ctx->handle == -1) {
 332                 DRM_DEBUG("Not enough free contexts.\n");
 333                 /* Should this return -EBUSY instead? */
 334                 return -ENOMEM;
 335         }
 336
 337         ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
 338         if (!ctx_entry) {
 339                 DRM_DEBUG("out of memory\n");
 340                 return -ENOMEM;
 341         }
 342
 343         INIT_LIST_HEAD(&ctx_entry->head);
 344         ctx_entry->handle = ctx->handle;
 345         ctx_entry->tag = file_priv;
 346
 347         mutex_lock(&dev->ctxlist_mutex);
 348         list_add(&ctx_entry->head, &dev->ctxlist);
 349         ++dev->ctx_count;
 350         mutex_unlock(&dev->ctxlist_mutex);
 351
 352         return 0;
 353 }
 354
 355 int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 356 {
 357         /* This does nothing */
 358         return 0;
 359 }
 360
 361 /**
 362  * Get context.
 363  *
 364  * \param inode device inode.
 365  * \param file_priv DRM file private.
 366  * \param cmd command.
 367  * \param arg user argument pointing to a drm_ctx structure.
 368  * \return zero on success or a negative number on failure.
 369  */
 370 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 371 {
 372         struct drm_ctx *ctx = data;
 373
 374         /* This is 0, because we don't handle any context flags */
 375         ctx->flags = 0;
 376
 377         return 0;
 378 }
 379
 380 /**
 381  * Switch context.
 382  *
 383  * \param inode device inode.
 384  * \param file_priv DRM file private.
 385  * \param cmd command.
 386  * \param arg user argument pointing to a drm_ctx structure.
 387  * \return zero on success or a negative number on failure.
 388  *
 389  * Calls context_switch().
 390  */
 391 int drm_switchctx(struct drm_device *dev, void *data,
 392                   struct drm_file *file_priv)
 393 {
 394         struct drm_ctx *ctx = data;
 395
 396         DRM_DEBUG("%d\n", ctx->handle);
 397         return drm_context_switch(dev, dev->last_context, ctx->handle);
 398 }
 399
 400 /**
 401  * New context.
 402  *
 403  * \param inode device inode.
 404  * \param file_priv DRM file private.
 405  * \param cmd command.
 406  * \param arg user argument pointing to a drm_ctx structure.
 407  * \return zero on success or a negative number on failure.
 408  *
 409  * Calls context_switch_complete().
 410  */
 411 int drm_newctx(struct drm_device *dev, void *data,
 412                struct drm_file *file_priv)
 413 {
 414         struct drm_ctx *ctx = data;
 415
 416         DRM_DEBUG("%d\n", ctx->handle);
 417         drm_context_switch_complete(dev, file_priv, ctx->handle);
 418
 419         return 0;
 420 }
 421
 422 /**
 423  * Remove context.
 424  *
 425  * \param inode device inode.
 426  * \param file_priv DRM file private.
 427  * \param cmd command.
 428  * \param arg user argument pointing to a drm_ctx structure.
 429  * \return zero on success or a negative number on failure.
 430  *
 431  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 432  */
 433 int drm_rmctx(struct drm_device *dev, void *data,
 434               struct drm_file *file_priv)
 435 {
 436         struct drm_ctx *ctx = data;
 437
 438         DRM_DEBUG("%d\n", ctx->handle);
 439         if (ctx->handle != DRM_KERNEL_CONTEXT) {
 440                 if (dev->driver->context_dtor)
 441                         dev->driver->context_dtor(dev, ctx->handle);
 442                 drm_ctxbitmap_free(dev, ctx->handle);
 443         }
 444
 445         mutex_lock(&dev->ctxlist_mutex);
 446         if (!list_empty(&dev->ctxlist)) {
 447                 struct drm_ctx_list *pos, *n;
 448
 449                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 450                         if (pos->handle == ctx->handle) {
 451                                 list_del(&pos->head);
 452                                 kfree(pos);
 453                                 --dev->ctx_count;
 454                         }
 455                 }
 456         }
 457         mutex_unlock(&dev->ctxlist_mutex);
 458
 459         return 0;
 460 }
 461
 462 /*@}*/