linux/sync.h

   1 /*
   2  * include/linux/sync.h
   3  *
   4  * Copyright (C) 2012 Google, Inc.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  */
  12
  13 #ifndef _LINUX_SYNC_H
  14 #define _LINUX_SYNC_H
  15
  16 #include <linux/types.h>
  17 #ifdef __KERNEL__
  18
  19 #include <linux/kref.h>
  20 #include <linux/ktime.h>
  21 #include <linux/list.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/wait.h>
  24
  25 struct sync_timeline;
  26 struct sync_pt;
  27 struct sync_fence;
  28 struct seq_file;
  29
  30 /**
  31  * struct sync_timeline_ops - sync object implementation ops
  32  * @driver_name:        name of the implentation
  33  * @dup:                duplicate a sync_pt
  34  * @has_signaled:       returns:
  35  *                        1 if pt has signaled
  36  *                        0 if pt has not signaled
  37  *                       <0 on error
  38  * @compare:            returns:
  39  *                        1 if b will signal before a
  40  *                        0 if a and b will signal at the same time
  41  *                       -1 if a will signabl before b
  42  * @free_pt:            called before sync_pt is freed
  43  * @release_obj:        called before sync_timeline is freed
  44  * @print_obj:          deprecated
  45  * @print_pt:           deprecated
  46  * @fill_driver_data:   write implmentation specific driver data to data.
  47  *                        should return an error if there is not enough room
  48  *                        as specified by size.  This information is returned
  49  *                        to userspace by SYNC_IOC_FENCE_INFO.
  50  * @timeline_value_str: fill str with the value of the sync_timeline's counter
  51  * @pt_value_str:       fill str with the value of the sync_pt
  52  */
  53 struct sync_timeline_ops {
  54         const char *driver_name;
  55
  56         /* required */
  57         struct sync_pt *(*dup)(struct sync_pt *pt);
  58
  59         /* required */
  60         int (*has_signaled)(struct sync_pt *pt);
  61
  62         /* required */
  63         int (*compare)(struct sync_pt *a, struct sync_pt *b);
  64
  65         /* optional */
  66         void (*free_pt)(struct sync_pt *sync_pt);
  67
  68         /* optional */
  69         void (*release_obj)(struct sync_timeline *sync_timeline);
  70
  71         /* deprecated */
  72         void (*print_obj)(struct seq_file *s,
  73                           struct sync_timeline *sync_timeline);
  74
  75         /* deprecated */
  76         void (*print_pt)(struct seq_file *s, struct sync_pt *sync_pt);
  77
  78         /* optional */
  79         int (*fill_driver_data)(struct sync_pt *syncpt, void *data, int size);
  80
  81         /* optional */
  82         void (*timeline_value_str)(struct sync_timeline *timeline, char *str,
  83                                    int size);
  84
  85         /* optional */
  86         void (*pt_value_str)(struct sync_pt *pt, char *str, int size);
  87 };
  88
  89 /**
  90  * struct sync_timeline - sync object
  91  * @kref:               reference count on fence.
  92  * @ops:                ops that define the implementaiton of the sync_timeline
  93  * @name:               name of the sync_timeline. Useful for debugging
  94  * @destoryed:          set when sync_timeline is destroyed
  95  * @child_list_head:    list of children sync_pts for this sync_timeline
  96  * @child_list_lock:    lock protecting @child_list_head, destroyed, and
  97  *                        sync_pt.status
  98  * @active_list_head:   list of active (unsignaled/errored) sync_pts
  99  * @sync_timeline_list: membership in global sync_timeline_list
 100  */
 101 struct sync_timeline {
 102         struct kref             kref;
 103         const struct sync_timeline_ops  *ops;
 104         char                    name[32];
 105
 106         /* protected by child_list_lock */
 107         bool                    destroyed;
 108
 109         struct list_head        child_list_head;
 110         spinlock_t              child_list_lock;
 111
 112         struct list_head        active_list_head;
 113         spinlock_t              active_list_lock;
 114
 115         struct list_head        sync_timeline_list;
 116 };
 117
 118 /**
 119  * struct sync_pt - sync point
 120  * @parent:             sync_timeline to which this sync_pt belongs
 121  * @child_list:         membership in sync_timeline.child_list_head
 122  * @active_list:        membership in sync_timeline.active_list_head
 123  * @signaled_list:      membership in temorary signaled_list on stack
 124  * @fence:              sync_fence to which the sync_pt belongs
 125  * @pt_list:            membership in sync_fence.pt_list_head
 126  * @status:             1: signaled, 0:active, <0: error
 127  * @timestamp:          time which sync_pt status transitioned from active to
 128  *                        singaled or error.
 129  */
 130 struct sync_pt {
 131         struct sync_timeline            *parent;
 132         struct list_head        child_list;
 133
 134         struct list_head        active_list;
 135         struct list_head        signaled_list;
 136
 137         struct sync_fence       *fence;
 138         struct list_head        pt_list;
 139
 140         /* protected by parent->active_list_lock */
 141         int                     status;
 142
 143         ktime_t                 timestamp;
 144 };
 145
 146 /**
 147  * struct sync_fence - sync fence
 148  * @file:               file representing this fence
 149  * @kref:               referenace count on fence.
 150  * @name:               name of sync_fence.  Useful for debugging
 151  * @pt_list_head:       list of sync_pts in ths fence.  immutable once fence
 152  *                        is created
 153  * @waiter_list_head:   list of asynchronous waiters on this fence
 154  * @waiter_list_lock:   lock protecting @waiter_list_head and @status
 155  * @status:             1: signaled, 0:active, <0: error
 156  *
 157  * @wq:                 wait queue for fence signaling
 158  * @sync_fence_list:    membership in global fence list
 159  */
 160 struct sync_fence {
 161         struct file             *file;
 162         struct kref             kref;
 163         char                    name[32];
 164
 165         /* this list is immutable once the fence is created */
 166         struct list_head        pt_list_head;
 167
 168         struct list_head        waiter_list_head;
 169         spinlock_t              waiter_list_lock; /* also protects status */
 170         int                     status;
 171
 172         wait_queue_head_t       wq;
 173
 174         struct list_head        sync_fence_list;
 175 };
 176
 177 struct sync_fence_waiter;
 178 typedef void (*sync_callback_t)(struct sync_fence *fence,
 179                                 struct sync_fence_waiter *waiter);
 180
 181 /**
 182  * struct sync_fence_waiter - metadata for asynchronous waiter on a fence
 183  * @waiter_list:        membership in sync_fence.waiter_list_head
 184  * @callback:           function pointer to call when fence signals
 185  * @callback_data:      pointer to pass to @callback
 186  */
 187 struct sync_fence_waiter {
 188         struct list_head        waiter_list;
 189
 190         sync_callback_t         callback;
 191 };
 192
 193 static inline void sync_fence_waiter_init(struct sync_fence_waiter *waiter,
 194                                           sync_callback_t callback)
 195 {
 196         waiter->callback = callback;
 197 }
 198
 199 /*
 200  * API for sync_timeline implementers
 201  */
 202
 203 /**
 204  * sync_timeline_create() - creates a sync object
 205  * @ops:        specifies the implemention ops for the object
 206  * @size:       size to allocate for this obj
 207  * @name:       sync_timeline name
 208  *
 209  * Creates a new sync_timeline which will use the implemetation specified by
 210  * @ops.  @size bytes will be allocated allowing for implemntation specific
 211  * data to be kept after the generic sync_timeline stuct.
 212  */
 213 struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
 214                                            int size, const char *name);
 215
 216 /**
 217  * sync_timeline_destory() - destorys a sync object
 218  * @obj:        sync_timeline to destroy
 219  *
 220  * A sync implemntation should call this when the @obj is going away
 221  * (i.e. module unload.)  @obj won't actually be freed until all its childern
 222  * sync_pts are freed.
 223  */
 224 void sync_timeline_destroy(struct sync_timeline *obj);
 225
 226 /**
 227  * sync_timeline_signal() - signal a status change on a sync_timeline
 228  * @obj:        sync_timeline to signal
 229  *
 230  * A sync implemntation should call this any time one of it's sync_pts
 231  * has signaled or has an error condition.
 232  */
 233 void sync_timeline_signal(struct sync_timeline *obj);
 234
 235 /**
 236  * sync_pt_create() - creates a sync pt
 237  * @parent:     sync_pt's parent sync_timeline
 238  * @size:       size to allocate for this pt
 239  *
 240  * Creates a new sync_pt as a chiled of @parent.  @size bytes will be
 241  * allocated allowing for implemntation specific data to be kept after
 242  * the generic sync_timeline struct.
 243  */
 244 struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size);
 245
 246 /**
 247  * sync_pt_free() - frees a sync pt
 248  * @pt:         sync_pt to free
 249  *
 250  * This should only be called on sync_pts which have been created but
 251  * not added to a fence.
 252  */
 253 void sync_pt_free(struct sync_pt *pt);
 254
 255 /**
 256  * sync_fence_create() - creates a sync fence
 257  * @name:       name of fence to create
 258  * @pt:         sync_pt to add to the fence
 259  *
 260  * Creates a fence containg @pt.  Once this is called, the fence takes
 261  * ownership of @pt.
 262  */
 263 struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt);
 264
 265 /*
 266  * API for sync_fence consumers
 267  */
 268
 269 /**
 270  * sync_fence_merge() - merge two fences
 271  * @name:       name of new fence
 272  * @a:          fence a
 273  * @b:          fence b
 274  *
 275  * Creates a new fence which contains copies of all the sync_pts in both
 276  * @a and @b.  @a and @b remain valid, independent fences.
 277  */
 278 struct sync_fence *sync_fence_merge(const char *name,
 279                                     struct sync_fence *a, struct sync_fence *b);
 280
 281 /**
 282  * sync_fence_fdget() - get a fence from an fd
 283  * @fd:         fd referencing a fence
 284  *
 285  * Ensures @fd references a valid fence, increments the refcount of the backing
 286  * file, and returns the fence.
 287  */
 288 struct sync_fence *sync_fence_fdget(int fd);
 289
 290 /**
 291  * sync_fence_put() - puts a refernnce of a sync fence
 292  * @fence:      fence to put
 293  *
 294  * Puts a reference on @fence.  If this is the last reference, the fence and
 295  * all it's sync_pts will be freed
 296  */
 297 void sync_fence_put(struct sync_fence *fence);
 298
 299 /**
 300  * sync_fence_install() - installs a fence into a file descriptor
 301  * @fence:      fence to instal
 302  * @fd:         file descriptor in which to install the fence
 303  *
 304  * Installs @fence into @fd.  @fd's should be acquired through get_unused_fd().
 305  */
 306 void sync_fence_install(struct sync_fence *fence, int fd);
 307
 308 /**
 309  * sync_fence_wait_async() - registers and async wait on the fence
 310  * @fence:              fence to wait on
 311  * @waiter:             waiter callback struck
 312  *
 313  * Returns 1 if @fence has already signaled.
 314  *
 315  * Registers a callback to be called when @fence signals or has an error.
 316  * @waiter should be initialized with sync_fence_waiter_init().
 317  */
 318 int sync_fence_wait_async(struct sync_fence *fence,
 319                           struct sync_fence_waiter *waiter);
 320
 321 /**
 322  * sync_fence_cancel_async() - cancels an async wait
 323  * @fence:              fence to wait on
 324  * @waiter:             waiter callback struck
 325  *
 326  * returns 0 if waiter was removed from fence's async waiter list.
 327  * returns -ENOENT if waiter was not found on fence's async waiter list.
 328  *
 329  * Cancels a previously registered async wait.  Will fail gracefully if
 330  * @waiter was never registered or if @fence has already signaled @waiter.
 331  */
 332 int sync_fence_cancel_async(struct sync_fence *fence,
 333                             struct sync_fence_waiter *waiter);
 334
 335 /**
 336  * sync_fence_wait() - wait on fence
 337  * @fence:      fence to wait on
 338  * @tiemout:    timeout in ms
 339  *
 340  * Wait for @fence to be signaled or have an error.  Waits indefinitely
 341  * if @timeout < 0
 342  */
 343 int sync_fence_wait(struct sync_fence *fence, long timeout);
 344
 345 #endif /* __KERNEL__ */
 346
 347 /**
 348  * struct sync_merge_data - data passed to merge ioctl
 349  * @fd2:        file descriptor of second fence
 350  * @name:       name of new fence
 351  * @fence:      returns the fd of the new fence to userspace
 352  */
 353 struct sync_merge_data {
 354         __s32   fd2; /* fd of second fence */
 355         char    name[32]; /* name of new fence */
 356         __s32   fence; /* fd on newly created fence */
 357 };
 358
 359 /**
 360  * struct sync_pt_info - detailed sync_pt information
 361  * @len:                length of sync_pt_info including any driver_data
 362  * @obj_name:           name of parent sync_timeline
 363  * @driver_name:        name of driver implmenting the parent
 364  * @status:             status of the sync_pt 0:active 1:signaled <0:error
 365  * @timestamp_ns:       timestamp of status change in nanoseconds
 366  * @driver_data:        any driver dependant data
 367  */
 368 struct sync_pt_info {
 369         __u32   len;
 370         char    obj_name[32];
 371         char    driver_name[32];
 372         __s32   status;
 373         __u64   timestamp_ns;
 374
 375         __u8    driver_data[0];
 376 };
 377
 378 /**
 379  * struct sync_fence_info_data - data returned from fence info ioctl
 380  * @len:        ioctl caller writes the size of the buffer its passing in.
 381  *              ioctl returns length of sync_fence_data reutnred to userspace
 382  *              including pt_info.
 383  * @name:       name of fence
 384  * @status:     status of fence. 1: signaled 0:active <0:error
 385  * @pt_info:    a sync_pt_info struct for every sync_pt in the fence
 386  */
 387 struct sync_fence_info_data {
 388         __u32   len;
 389         char    name[32];
 390         __s32   status;
 391
 392         __u8    pt_info[0];
 393 };
 394
 395 #define SYNC_IOC_MAGIC          '>'
 396
 397 /**
 398  * DOC: SYNC_IOC_WAIT - wait for a fence to signal
 399  *
 400  * pass timeout in milliseconds.  Waits indefinitely timeout < 0.
 401  */
 402 #define SYNC_IOC_WAIT           _IOW(SYNC_IOC_MAGIC, 0, __s32)
 403
 404 /**
 405  * DOC: SYNC_IOC_MERGE - merge two fences
 406  *
 407  * Takes a struct sync_merge_data.  Creates a new fence containing copies of
 408  * the sync_pts in both the calling fd and sync_merge_data.fd2.  Returns the
 409  * new fence's fd in sync_merge_data.fence
 410  */
 411 #define SYNC_IOC_MERGE          _IOWR(SYNC_IOC_MAGIC, 1, struct sync_merge_data)
 412
 413 /**
 414  * DOC: SYNC_IOC_FENCE_INFO - get detailed information on a fence
 415  *
 416  * Takes a struct sync_fence_info_data with extra space allocated for pt_info.
 417  * Caller should write the size of the buffer into len.  On return, len is
 418  * updated to reflect the total size of the sync_fence_info_data including
 419  * pt_info.
 420  *
 421  * pt_info is a buffer containing sync_pt_infos for every sync_pt in the fence.
 422  * To itterate over the sync_pt_infos, use the sync_pt_info.len field.
 423  */
 424 #define SYNC_IOC_FENCE_INFO     _IOWR(SYNC_IOC_MAGIC, 2,\
 425         struct sync_fence_info_data)
 426
 427 #endif /* _LINUX_SYNC_H */