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