include/drm/ttm/ttm_object.h

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  27 /*
  28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  29  */
  30 /** @file ttm_object.h
  31  *
  32  * Base- and reference object implementation for the various
  33  * ttm objects. Implements reference counting, minimal security checks
  34  * and release on file close.
  35  */
  36
  37 #ifndef _TTM_OBJECT_H_
  38 #define _TTM_OBJECT_H_
  39
  40 #include <linux/list.h>
  41 #include <drm/drm_hashtab.h>
  42 #include <linux/kref.h>
  43 #include <linux/rcupdate.h>
  44 #include <linux/dma-buf.h>
  45 #include <ttm/ttm_memory.h>
  46
  47 /**
  48  * enum ttm_ref_type
  49  *
  50  * Describes what type of reference a ref object holds.
  51  *
  52  * TTM_REF_USAGE is a simple refcount on a base object.
  53  *
  54  * TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
  55  * buffer object.
  56  *
  57  * TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
  58  * buffer object.
  59  *
  60  */
  61
  62 enum ttm_ref_type {
  63         TTM_REF_USAGE,
  64         TTM_REF_SYNCCPU_READ,
  65         TTM_REF_SYNCCPU_WRITE,
  66         TTM_REF_NUM
  67 };
  68
  69 /**
  70  * enum ttm_object_type
  71  *
  72  * One entry per ttm object type.
  73  * Device-specific types should use the
  74  * ttm_driver_typex types.
  75  */
  76
  77 enum ttm_object_type {
  78         ttm_fence_type,
  79         ttm_buffer_type,
  80         ttm_lock_type,
  81         ttm_prime_type,
  82         ttm_driver_type0 = 256,
  83         ttm_driver_type1,
  84         ttm_driver_type2,
  85         ttm_driver_type3,
  86         ttm_driver_type4,
  87         ttm_driver_type5
  88 };
  89
  90 struct ttm_object_file;
  91 struct ttm_object_device;
  92
  93 /**
  94  * struct ttm_base_object
  95  *
  96  * @hash: hash entry for the per-device object hash.
  97  * @type: derived type this object is base class for.
  98  * @shareable: Other ttm_object_files can access this object.
  99  *
 100  * @tfile: Pointer to ttm_object_file of the creator.
 101  * NULL if the object was not created by a user request.
 102  * (kernel object).
 103  *
 104  * @refcount: Number of references to this object, not
 105  * including the hash entry. A reference to a base object can
 106  * only be held by a ref object.
 107  *
 108  * @refcount_release: A function to be called when there are
 109  * no more references to this object. This function should
 110  * destroy the object (or make sure destruction eventually happens),
 111  * and when it is called, the object has
 112  * already been taken out of the per-device hash. The parameter
 113  * "base" should be set to NULL by the function.
 114  *
 115  * @ref_obj_release: A function to be called when a reference object
 116  * with another ttm_ref_type than TTM_REF_USAGE is deleted.
 117  * This function may, for example, release a lock held by a user-space
 118  * process.
 119  *
 120  * This struct is intended to be used as a base struct for objects that
 121  * are visible to user-space. It provides a global name, race-safe
 122  * access and refcounting, minimal access contol and hooks for unref actions.
 123  */
 124
 125 struct ttm_base_object {
 126         struct rcu_head rhead;
 127         struct drm_hash_item hash;
 128         enum ttm_object_type object_type;
 129         bool shareable;
 130         struct ttm_object_file *tfile;
 131         struct kref refcount;
 132         void (*refcount_release) (struct ttm_base_object **base);
 133         void (*ref_obj_release) (struct ttm_base_object *base,
 134                                  enum ttm_ref_type ref_type);
 135 };
 136
 137
 138 /**
 139  * struct ttm_prime_object - Modified base object that is prime-aware
 140  *
 141  * @base: struct ttm_base_object that we derive from
 142  * @mutex: Mutex protecting the @dma_buf member.
 143  * @size: Size of the dma_buf associated with this object
 144  * @real_type: Type of the underlying object. Needed since we're setting
 145  * the value of @base::object_type to ttm_prime_type
 146  * @dma_buf: Non ref-coutned pointer to a struct dma_buf created from this
 147  * object.
 148  * @refcount_release: The underlying object's release method. Needed since
 149  * we set @base::refcount_release to our own release method.
 150  */
 151
 152 struct ttm_prime_object {
 153         struct ttm_base_object base;
 154         struct mutex mutex;
 155         size_t size;
 156         enum ttm_object_type real_type;
 157         struct dma_buf *dma_buf;
 158         void (*refcount_release) (struct ttm_base_object **);
 159 };
 160
 161 /**
 162  * ttm_base_object_init
 163  *
 164  * @tfile: Pointer to a struct ttm_object_file.
 165  * @base: The struct ttm_base_object to initialize.
 166  * @shareable: This object is shareable with other applcations.
 167  * (different @tfile pointers.)
 168  * @type: The object type.
 169  * @refcount_release: See the struct ttm_base_object description.
 170  * @ref_obj_release: See the struct ttm_base_object description.
 171  *
 172  * Initializes a struct ttm_base_object.
 173  */
 174
 175 extern int ttm_base_object_init(struct ttm_object_file *tfile,
 176                                 struct ttm_base_object *base,
 177                                 bool shareable,
 178                                 enum ttm_object_type type,
 179                                 void (*refcount_release) (struct ttm_base_object
 180                                                           **),
 181                                 void (*ref_obj_release) (struct ttm_base_object
 182                                                          *,
 183                                                          enum ttm_ref_type
 184                                                          ref_type));
 185
 186 /**
 187  * ttm_base_object_lookup
 188  *
 189  * @tfile: Pointer to a struct ttm_object_file.
 190  * @key: Hash key
 191  *
 192  * Looks up a struct ttm_base_object with the key @key.
 193  */
 194
 195 extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
 196                                                       *tfile, uint32_t key);
 197
 198 /**
 199  * ttm_base_object_lookup_for_ref
 200  *
 201  * @tdev: Pointer to a struct ttm_object_device.
 202  * @key: Hash key
 203  *
 204  * Looks up a struct ttm_base_object with the key @key.
 205  * This function should only be used when the struct tfile associated with the
 206  * caller doesn't yet have a reference to the base object.
 207  */
 208
 209 extern struct ttm_base_object *
 210 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key);
 211
 212 /**
 213  * ttm_base_object_unref
 214  *
 215  * @p_base: Pointer to a pointer referencing a struct ttm_base_object.
 216  *
 217  * Decrements the base object refcount and clears the pointer pointed to by
 218  * p_base.
 219  */
 220
 221 extern void ttm_base_object_unref(struct ttm_base_object **p_base);
 222
 223 /**
 224  * ttm_ref_object_add.
 225  *
 226  * @tfile: A struct ttm_object_file representing the application owning the
 227  * ref_object.
 228  * @base: The base object to reference.
 229  * @ref_type: The type of reference.
 230  * @existed: Upon completion, indicates that an identical reference object
 231  * already existed, and the refcount was upped on that object instead.
 232  * @require_existed: Fail with -EPERM if an identical ref object didn't
 233  * already exist.
 234  *
 235  * Checks that the base object is shareable and adds a ref object to it.
 236  *
 237  * Adding a ref object to a base object is basically like referencing the
 238  * base object, but a user-space application holds the reference. When the
 239  * file corresponding to @tfile is closed, all its reference objects are
 240  * deleted. A reference object can have different types depending on what
 241  * it's intended for. It can be refcounting to prevent object destruction,
 242  * When user-space takes a lock, it can add a ref object to that lock to
 243  * make sure the lock is released if the application dies. A ref object
 244  * will hold a single reference on a base object.
 245  */
 246 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
 247                               struct ttm_base_object *base,
 248                               enum ttm_ref_type ref_type, bool *existed,
 249                               bool require_existed);
 250
 251 extern bool ttm_ref_object_exists(struct ttm_object_file *tfile,
 252                                   struct ttm_base_object *base);
 253
 254 /**
 255  * ttm_ref_object_base_unref
 256  *
 257  * @key: Key representing the base object.
 258  * @ref_type: Ref type of the ref object to be dereferenced.
 259  *
 260  * Unreference a ref object with type @ref_type
 261  * on the base object identified by @key. If there are no duplicate
 262  * references, the ref object will be destroyed and the base object
 263  * will be unreferenced.
 264  */
 265 extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
 266                                      unsigned long key,
 267                                      enum ttm_ref_type ref_type);
 268
 269 /**
 270  * ttm_object_file_init - initialize a struct ttm_object file
 271  *
 272  * @tdev: A struct ttm_object device this file is initialized on.
 273  * @hash_order: Order of the hash table used to hold the reference objects.
 274  *
 275  * This is typically called by the file_ops::open function.
 276  */
 277
 278 extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
 279                                                     *tdev,
 280                                                     unsigned int hash_order);
 281
 282 /**
 283  * ttm_object_file_release - release data held by a ttm_object_file
 284  *
 285  * @p_tfile: Pointer to pointer to the ttm_object_file object to release.
 286  * *p_tfile will be set to NULL by this function.
 287  *
 288  * Releases all data associated by a ttm_object_file.
 289  * Typically called from file_ops::release. The caller must
 290  * ensure that there are no concurrent users of tfile.
 291  */
 292
 293 extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
 294
 295 /**
 296  * ttm_object device init - initialize a struct ttm_object_device
 297  *
 298  * @mem_glob: struct ttm_mem_global for memory accounting.
 299  * @hash_order: Order of hash table used to hash the base objects.
 300  * @ops: DMA buf ops for prime objects of this device.
 301  *
 302  * This function is typically called on device initialization to prepare
 303  * data structures needed for ttm base and ref objects.
 304  */
 305
 306 extern struct ttm_object_device *
 307 ttm_object_device_init(struct ttm_mem_global *mem_glob,
 308                        unsigned int hash_order,
 309                        const struct dma_buf_ops *ops);
 310
 311 /**
 312  * ttm_object_device_release - release data held by a ttm_object_device
 313  *
 314  * @p_tdev: Pointer to pointer to the ttm_object_device object to release.
 315  * *p_tdev will be set to NULL by this function.
 316  *
 317  * Releases all data associated by a ttm_object_device.
 318  * Typically called from driver::unload before the destruction of the
 319  * device private data structure.
 320  */
 321
 322 extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
 323
 324 #define ttm_base_object_kfree(__object, __base)\
 325         kfree_rcu(__object, __base.rhead)
 326
 327 extern int ttm_prime_object_init(struct ttm_object_file *tfile,
 328                                  size_t size,
 329                                  struct ttm_prime_object *prime,
 330                                  bool shareable,
 331                                  enum ttm_object_type type,
 332                                  void (*refcount_release)
 333                                  (struct ttm_base_object **),
 334                                  void (*ref_obj_release)
 335                                  (struct ttm_base_object *,
 336                                   enum ttm_ref_type ref_type));
 337
 338 static inline enum ttm_object_type
 339 ttm_base_object_type(struct ttm_base_object *base)
 340 {
 341         return (base->object_type == ttm_prime_type) ?
 342                 container_of(base, struct ttm_prime_object, base)->real_type :
 343                 base->object_type;
 344 }
 345 extern int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
 346                                   int fd, u32 *handle);
 347 extern int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
 348                                   uint32_t handle, uint32_t flags,
 349                                   int *prime_fd);
 350
 351 #define ttm_prime_object_kfree(__obj, __prime)          \
 352         kfree_rcu(__obj, __prime.base.rhead)
 353 #endif