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_hashtab.h"
  42 #include <linux/kref.h>
  43 #include <ttm/ttm_memory.h>
  44
  45 /**
  46  * enum ttm_ref_type
  47  *
  48  * Describes what type of reference a ref object holds.
  49  *
  50  * TTM_REF_USAGE is a simple refcount on a base object.
  51  *
  52  * TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
  53  * buffer object.
  54  *
  55  * TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
  56  * buffer object.
  57  *
  58  */
  59
  60 enum ttm_ref_type {
  61         TTM_REF_USAGE,
  62         TTM_REF_SYNCCPU_READ,
  63         TTM_REF_SYNCCPU_WRITE,
  64         TTM_REF_NUM
  65 };
  66
  67 /**
  68  * enum ttm_object_type
  69  *
  70  * One entry per ttm object type.
  71  * Device-specific types should use the
  72  * ttm_driver_typex types.
  73  */
  74
  75 enum ttm_object_type {
  76         ttm_fence_type,
  77         ttm_buffer_type,
  78         ttm_lock_type,
  79         ttm_driver_type0 = 256,
  80         ttm_driver_type1,
  81         ttm_driver_type2,
  82         ttm_driver_type3,
  83         ttm_driver_type4,
  84         ttm_driver_type5
  85 };
  86
  87 struct ttm_object_file;
  88 struct ttm_object_device;
  89
  90 /**
  91  * struct ttm_base_object
  92  *
  93  * @hash: hash entry for the per-device object hash.
  94  * @type: derived type this object is base class for.
  95  * @shareable: Other ttm_object_files can access this object.
  96  *
  97  * @tfile: Pointer to ttm_object_file of the creator.
  98  * NULL if the object was not created by a user request.
  99  * (kernel object).
 100  *
 101  * @refcount: Number of references to this object, not
 102  * including the hash entry. A reference to a base object can
 103  * only be held by a ref object.
 104  *
 105  * @refcount_release: A function to be called when there are
 106  * no more references to this object. This function should
 107  * destroy the object (or make sure destruction eventually happens),
 108  * and when it is called, the object has
 109  * already been taken out of the per-device hash. The parameter
 110  * "base" should be set to NULL by the function.
 111  *
 112  * @ref_obj_release: A function to be called when a reference object
 113  * with another ttm_ref_type than TTM_REF_USAGE is deleted.
 114  * This function may, for example, release a lock held by a user-space
 115  * process.
 116  *
 117  * This struct is intended to be used as a base struct for objects that
 118  * are visible to user-space. It provides a global name, race-safe
 119  * access and refcounting, minimal access contol and hooks for unref actions.
 120  */
 121
 122 struct ttm_base_object {
 123         struct drm_hash_item hash;
 124         enum ttm_object_type object_type;
 125         bool shareable;
 126         struct ttm_object_file *tfile;
 127         struct kref refcount;
 128         void (*refcount_release) (struct ttm_base_object **base);
 129         void (*ref_obj_release) (struct ttm_base_object *base,
 130                                  enum ttm_ref_type ref_type);
 131 };
 132
 133 /**
 134  * ttm_base_object_init
 135  *
 136  * @tfile: Pointer to a struct ttm_object_file.
 137  * @base: The struct ttm_base_object to initialize.
 138  * @shareable: This object is shareable with other applcations.
 139  * (different @tfile pointers.)
 140  * @type: The object type.
 141  * @refcount_release: See the struct ttm_base_object description.
 142  * @ref_obj_release: See the struct ttm_base_object description.
 143  *
 144  * Initializes a struct ttm_base_object.
 145  */
 146
 147 extern int ttm_base_object_init(struct ttm_object_file *tfile,
 148                                 struct ttm_base_object *base,
 149                                 bool shareable,
 150                                 enum ttm_object_type type,
 151                                 void (*refcount_release) (struct ttm_base_object
 152                                                           **),
 153                                 void (*ref_obj_release) (struct ttm_base_object
 154                                                          *,
 155                                                          enum ttm_ref_type
 156                                                          ref_type));
 157
 158 /**
 159  * ttm_base_object_lookup
 160  *
 161  * @tfile: Pointer to a struct ttm_object_file.
 162  * @key: Hash key
 163  *
 164  * Looks up a struct ttm_base_object with the key @key.
 165  * Also verifies that the object is visible to the application, by
 166  * comparing the @tfile argument and checking the object shareable flag.
 167  */
 168
 169 extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
 170                                                       *tfile, uint32_t key);
 171
 172 /**
 173  * ttm_base_object_unref
 174  *
 175  * @p_base: Pointer to a pointer referencing a struct ttm_base_object.
 176  *
 177  * Decrements the base object refcount and clears the pointer pointed to by
 178  * p_base.
 179  */
 180
 181 extern void ttm_base_object_unref(struct ttm_base_object **p_base);
 182
 183 /**
 184  * ttm_ref_object_add.
 185  *
 186  * @tfile: A struct ttm_object_file representing the application owning the
 187  * ref_object.
 188  * @base: The base object to reference.
 189  * @ref_type: The type of reference.
 190  * @existed: Upon completion, indicates that an identical reference object
 191  * already existed, and the refcount was upped on that object instead.
 192  *
 193  * Adding a ref object to a base object is basically like referencing the
 194  * base object, but a user-space application holds the reference. When the
 195  * file corresponding to @tfile is closed, all its reference objects are
 196  * deleted. A reference object can have different types depending on what
 197  * it's intended for. It can be refcounting to prevent object destruction,
 198  * When user-space takes a lock, it can add a ref object to that lock to
 199  * make sure the lock is released if the application dies. A ref object
 200  * will hold a single reference on a base object.
 201  */
 202 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
 203                               struct ttm_base_object *base,
 204                               enum ttm_ref_type ref_type, bool *existed);
 205 /**
 206  * ttm_ref_object_base_unref
 207  *
 208  * @key: Key representing the base object.
 209  * @ref_type: Ref type of the ref object to be dereferenced.
 210  *
 211  * Unreference a ref object with type @ref_type
 212  * on the base object identified by @key. If there are no duplicate
 213  * references, the ref object will be destroyed and the base object
 214  * will be unreferenced.
 215  */
 216 extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
 217                                      unsigned long key,
 218                                      enum ttm_ref_type ref_type);
 219
 220 /**
 221  * ttm_object_file_init - initialize a struct ttm_object file
 222  *
 223  * @tdev: A struct ttm_object device this file is initialized on.
 224  * @hash_order: Order of the hash table used to hold the reference objects.
 225  *
 226  * This is typically called by the file_ops::open function.
 227  */
 228
 229 extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
 230                                                     *tdev,
 231                                                     unsigned int hash_order);
 232
 233 /**
 234  * ttm_object_file_release - release data held by a ttm_object_file
 235  *
 236  * @p_tfile: Pointer to pointer to the ttm_object_file object to release.
 237  * *p_tfile will be set to NULL by this function.
 238  *
 239  * Releases all data associated by a ttm_object_file.
 240  * Typically called from file_ops::release. The caller must
 241  * ensure that there are no concurrent users of tfile.
 242  */
 243
 244 extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
 245
 246 /**
 247  * ttm_object device init - initialize a struct ttm_object_device
 248  *
 249  * @hash_order: Order of hash table used to hash the base objects.
 250  *
 251  * This function is typically called on device initialization to prepare
 252  * data structures needed for ttm base and ref objects.
 253  */
 254
 255 extern struct ttm_object_device *ttm_object_device_init
 256     (struct ttm_mem_global *mem_glob, unsigned int hash_order);
 257
 258 /**
 259  * ttm_object_device_release - release data held by a ttm_object_device
 260  *
 261  * @p_tdev: Pointer to pointer to the ttm_object_device object to release.
 262  * *p_tdev will be set to NULL by this function.
 263  *
 264  * Releases all data associated by a ttm_object_device.
 265  * Typically called from driver::unload before the destruction of the
 266  * device private data structure.
 267  */
 268
 269 extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
 270
 271 #endif