firmware/export/thread.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2002 by Ulf Ralberg
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19 #ifndef THREAD_H
  20 #define THREAD_H
  21
  22 #include "config.h"
  23 #include <inttypes.h>
  24 #include <stddef.h>
  25 #include <stdbool.h>
  26
  27 /* Priority scheduling (when enabled with HAVE_PRIORITY_SCHEDULING) works
  28  * by giving high priority threads more CPU time than less priority threads
  29  * when they need it. Priority is differential such that the priority
  30  * difference between a lower priority runnable thread and the highest priority
  31  * runnable thread determines the amount of aging nescessary for the lower
  32  * priority thread to be scheduled in order to prevent starvation.
  33  *
  34  * If software playback codec pcm buffer is going down to critical, codec
  35  * can gradually raise its own priority to override user interface and
  36  * prevent playback skipping.
  37  */
  38 #define PRIORITY_RESERVED_HIGH   0   /* Reserved */
  39 #define PRIORITY_RESERVED_LOW    32  /* Reserved */
  40 #define HIGHEST_PRIORITY         1   /* The highest possible thread priority */
  41 #define LOWEST_PRIORITY          31  /* The lowest possible thread priority */
  42 /* Realtime range reserved for threads that will not allow threads of lower
  43  * priority to age and run (future expansion) */
  44 #define PRIORITY_REALTIME_1      1
  45 #define PRIORITY_REALTIME_2      2
  46 #define PRIORITY_REALTIME_3      3
  47 #define PRIORITY_REALTIME_4      4
  48 #define PRIORITY_REALTIME        4   /* Lowest realtime range */
  49 #define PRIORITY_USER_INTERFACE  16  /* The main thread */
  50 #define PRIORITY_RECORDING       16  /* Recording thread */
  51 #define PRIORITY_PLAYBACK        16  /* Variable between this and MAX */
  52 #define PRIORITY_PLAYBACK_MAX    5   /* Maximum allowable playback priority */
  53 #define PRIORITY_BUFFERING       16  /* Codec buffering thread */
  54 #define PRIORITY_SYSTEM          18  /* All other firmware threads */
  55 #define PRIORITY_BACKGROUND      20  /* Normal application threads */
  56 #define NUM_PRIORITIES           32
  57 #define PRIORITY_IDLE            32  /* Priority representative of no tasks */
  58
  59 /* TODO: Only a minor tweak to create_thread would be needed to let
  60  * thread slots be caller allocated - no essential threading functionality
  61  * depends upon an array */
  62 #if CONFIG_CODEC == SWCODEC
  63
  64 #ifdef HAVE_RECORDING
  65 #define MAXTHREADS  18
  66 #else
  67 #define MAXTHREADS  17
  68 #endif
  69
  70 #else
  71 #define MAXTHREADS  11
  72 #endif /* CONFIG_CODE == * */
  73
  74 #define DEFAULT_STACK_SIZE 0x400 /* Bytes */
  75
  76 #ifndef SIMULATOR
  77 /* Need to keep structures inside the header file because debug_menu
  78  * needs them. */
  79 #ifdef CPU_COLDFIRE
  80 struct regs
  81 {
  82     uint32_t macsr; /*     0 - EMAC status register */
  83     uint32_t d[6];  /*  4-24 - d2-d7 */
  84     uint32_t a[5];  /* 28-44 - a2-a6 */
  85     uint32_t sp;    /*    48 - Stack pointer (a7) */
  86     uint32_t start; /*    52 - Thread start address, or NULL when started */
  87 };
  88 #elif CONFIG_CPU == SH7034
  89 struct regs
  90 {
  91     uint32_t r[7];  /*  0-24 - Registers r8 thru r14 */
  92     uint32_t sp;    /*    28 - Stack pointer (r15) */
  93     uint32_t pr;    /*    32 - Procedure register */
  94     uint32_t start; /*    36 - Thread start address, or NULL when started */
  95 };
  96 #elif defined(CPU_ARM)
  97 struct regs
  98 {
  99     uint32_t r[8];  /*  0-28 - Registers r4-r11 */
 100     uint32_t sp;    /*    32 - Stack pointer (r13) */
 101     uint32_t lr;    /*    36 - r14 (lr) */
 102     uint32_t start; /*    40 - Thread start address, or NULL when started */
 103 };
 104 #endif /* CONFIG_CPU */
 105 #else
 106 struct regs
 107 {
 108     void *t;             /* Simulator OS thread */
 109     void *s;             /* Semaphore for blocking and wakeup */
 110     void (*start)(void); /* Start function */
 111 };
 112 #endif /* !SIMULATOR */
 113
 114 /* NOTE: The use of the word "queue" may also refer to a linked list of
 115    threads being maintainted that are normally dealt with in FIFO order
 116    and not nescessarily kernel event_queue */
 117 enum
 118 {
 119     /* States without a timeout must be first */
 120     STATE_KILLED = 0,    /* Thread is killed (default) */
 121     STATE_RUNNING,       /* Thread is currently running */
 122     STATE_BLOCKED,       /* Thread is indefinitely blocked on a queue */
 123     /* These states involve adding the thread to the tmo list */
 124     STATE_SLEEPING,      /* Thread is sleeping with a timeout */
 125     STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
 126     /* Miscellaneous states */
 127     STATE_FROZEN,        /* Thread is suspended and will not run until
 128                             thread_thaw is called with its ID */
 129     THREAD_NUM_STATES,
 130     TIMEOUT_STATE_FIRST = STATE_SLEEPING,
 131 };
 132
 133 #if NUM_CORES > 1
 134 /* Pointer value for name field to indicate thread is being killed. Using
 135  * an alternate STATE_* won't work since that would interfere with operation
 136  * while the thread is still running. */
 137 #define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
 138 #endif
 139
 140 /* Link information for lists thread is in */
 141 struct thread_entry; /* forward */
 142 struct thread_list
 143 {
 144     struct thread_entry *prev; /* Previous thread in a list */
 145     struct thread_entry *next; /* Next thread in a list */
 146 };
 147
 148 /* Small objects for core-wise mutual exclusion */
 149 #if CONFIG_CORELOCK == SW_CORELOCK
 150 /* No reliable atomic instruction available - use Peterson's algorithm */
 151 struct corelock
 152 {
 153     volatile unsigned char myl[NUM_CORES];
 154     volatile unsigned char turn;
 155 } __attribute__((packed));
 156
 157 void corelock_init(struct corelock *cl);
 158 void corelock_lock(struct corelock *cl);
 159 int corelock_try_lock(struct corelock *cl);
 160 void corelock_unlock(struct corelock *cl);
 161 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 162 /* Use native atomic swap/exchange instruction */
 163 struct corelock
 164 {
 165     volatile unsigned char locked;
 166 } __attribute__((packed));
 167
 168 #define corelock_init(cl) \
 169     ({ (cl)->locked = 0; })
 170 #define corelock_lock(cl) \
 171     ({ while (test_and_set(&(cl)->locked, 1)); })
 172 #define corelock_try_lock(cl) \
 173     ({ test_and_set(&(cl)->locked, 1) ? 0 : 1; })
 174 #define corelock_unlock(cl) \
 175     ({ (cl)->locked = 0; })
 176 #else
 177 /* No atomic corelock op needed or just none defined */
 178 #define corelock_init(cl)
 179 #define corelock_lock(cl)
 180 #define corelock_try_lock(cl)
 181 #define corelock_unlock(cl)
 182 #endif /* core locking selection */
 183
 184 #ifdef HAVE_PRIORITY_SCHEDULING
 185 struct blocker
 186 {
 187     struct thread_entry *thread;   /* thread blocking other threads
 188                                       (aka. object owner) */
 189     int priority;                  /* highest priority waiter */
 190     struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
 191 };
 192
 193 /* Choices of wakeup protocol */
 194
 195 /* For transfer of object ownership by one thread to another thread by
 196  * the owning thread itself (mutexes) */
 197 struct thread_entry *
 198     wakeup_priority_protocol_transfer(struct thread_entry *thread);
 199
 200 /* For release by owner where ownership doesn't change - other threads,
 201  * interrupts, timeouts, etc. (mutex timeout, queues) */
 202 struct thread_entry *
 203     wakeup_priority_protocol_release(struct thread_entry *thread);
 204
 205
 206 struct priority_distribution
 207 {
 208     uint8_t  hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
 209     uint32_t mask;                 /* Bitmask of hist entries that are not zero */
 210 };
 211
 212 #endif /* HAVE_PRIORITY_SCHEDULING */
 213
 214 /* Information kept in each thread slot
 215  * members are arranged according to size - largest first - in order
 216  * to ensure both alignment and packing at the same time.
 217  */
 218 struct thread_entry
 219 {
 220     struct regs context;       /* Register context at switch -
 221                                   _must_ be first member */
 222     uintptr_t *stack;          /* Pointer to top of stack */
 223     const char *name;          /* Thread name */
 224     long tmo_tick;             /* Tick when thread should be woken from
 225                                   timeout -
 226                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 227     struct thread_list l;      /* Links for blocked/waking/running -
 228                                   circular linkage in both directions */
 229     struct thread_list tmo;    /* Links for timeout list -
 230                                   Circular in reverse direction, NULL-terminated in
 231                                   forward direction -
 232                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 233     struct thread_entry **bqp; /* Pointer to list variable in kernel
 234                                   object where thread is blocked - used
 235                                   for implicit unblock and explicit wake
 236                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 237 #if NUM_CORES > 1
 238     struct corelock *obj_cl;   /* Object corelock where thead is blocked -
 239                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
 240 #endif
 241     struct thread_entry *queue; /* List of threads waiting for thread to be
 242                                   removed */
 243 #ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
 244     #define HAVE_WAKEUP_EXT_CB
 245     void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
 246                                   performs special steps needed when being
 247                                   forced off of an object's wait queue that
 248                                   go beyond the standard wait queue removal
 249                                   and priority disinheritance */
 250     /* Only enabled when using queue_send for now */
 251 #endif
 252 #if defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || NUM_CORES > 1
 253     intptr_t retval;           /* Return value from a blocked operation/
 254                                   misc. use */
 255 #endif
 256 #ifdef HAVE_PRIORITY_SCHEDULING
 257     /* Priority summary of owned objects that support inheritance */
 258     struct blocker *blocker;   /* Pointer to blocker when this thread is blocked
 259                                   on an object that supports PIP -
 260                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 261     struct priority_distribution pdist; /* Priority summary of owned objects
 262                                   that have blocked threads and thread's own
 263                                   base priority */
 264     int skip_count;            /* Number of times skipped if higher priority
 265                                   thread was running */
 266 #endif
 267     unsigned short stack_size; /* Size of stack in bytes */
 268 #ifdef HAVE_PRIORITY_SCHEDULING
 269     unsigned char base_priority; /* Base priority (set explicitly during
 270                                   creation or thread_set_priority) */
 271     unsigned char priority;    /* Scheduled priority (higher of base or
 272                                   all threads blocked by this one) */
 273 #endif
 274     unsigned char state;       /* Thread slot state (STATE_*) */
 275 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 276     unsigned char cpu_boost;   /* CPU frequency boost flag */
 277 #endif
 278 #if NUM_CORES > 1
 279     unsigned char core;        /* The core to which thread belongs */
 280     struct corelock waiter_cl; /* Corelock for thread_wait */
 281     struct corelock slot_cl;   /* Corelock to lock thread slot */
 282 #endif
 283 };
 284
 285 #if NUM_CORES > 1
 286 /* Operations to be performed just before stopping a thread and starting
 287    a new one if specified before calling switch_thread */
 288 enum
 289 {
 290     TBOP_CLEAR = 0,       /* No operation to do */
 291     TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
 292     TBOP_SWITCH_CORE,     /* Call the core switch preparation routine */
 293 };
 294
 295 struct thread_blk_ops
 296 {
 297     struct corelock *cl_p;    /* pointer to corelock */
 298     unsigned char    flags;   /* TBOP_* flags */
 299 };
 300 #endif /* NUM_CORES > 1 */
 301
 302 /* Information kept for each core
 303  * Member are arranged for the same reason as in thread_entry
 304  */
 305 struct core_entry
 306 {
 307     /* "Active" lists - core is constantly active on these and are never
 308        locked and interrupts do not access them */
 309     struct thread_entry *running;  /* threads that are running (RTR) */
 310     struct thread_entry *timeout;  /* threads that are on a timeout before
 311                                       running again */
 312     struct thread_entry *block_task; /* Task going off running list */
 313 #ifdef HAVE_PRIORITY_SCHEDULING
 314     struct priority_distribution rtr; /* Summary of running and ready-to-run
 315                                          threads */
 316 #endif
 317     long next_tmo_check;           /* soonest time to check tmo threads */
 318 #if NUM_CORES > 1
 319     struct thread_blk_ops blk_ops; /* operations to perform when
 320                                       blocking a thread */
 321 #ifdef HAVE_PRIORITY_SCHEDULING
 322     struct corelock rtr_cl;        /* Lock for rtr list */
 323 #endif
 324 #endif /* NUM_CORES */
 325 };
 326
 327 #ifdef HAVE_PRIORITY_SCHEDULING
 328 #define IF_PRIO(...)    __VA_ARGS__
 329 #define IFN_PRIO(...)
 330 #else
 331 #define IF_PRIO(...)
 332 #define IFN_PRIO(...)   __VA_ARGS__
 333 #endif
 334
 335 /* Macros generate better code than an inline function is this case */
 336 #if (defined (CPU_PP) || defined (CPU_ARM))
 337 /* atomic */
 338 #if CONFIG_CORELOCK == SW_CORELOCK
 339 #define test_and_set(a, v, cl) \
 340     xchg8((a), (v), (cl))
 341 /* atomic */
 342 #define xchg8(a, v, cl) \
 343 ({  uint32_t o;            \
 344     corelock_lock(cl);     \
 345     o = *(uint8_t *)(a);   \
 346     *(uint8_t *)(a) = (v); \
 347     corelock_unlock(cl);   \
 348     o; })
 349 #define xchg32(a, v, cl) \
 350 ({  uint32_t o;             \
 351     corelock_lock(cl);      \
 352     o = *(uint32_t *)(a);   \
 353     *(uint32_t *)(a) = (v); \
 354     corelock_unlock(cl);    \
 355     o; })
 356 #define xchgptr(a, v, cl) \
 357 ({  typeof (*(a)) o;     \
 358     corelock_lock(cl);   \
 359     o = *(a);            \
 360     *(a) = (v);          \
 361     corelock_unlock(cl); \
 362     o; })
 363 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 364 /* atomic */
 365 #define test_and_set(a, v, ...) \
 366     xchg8((a), (v))
 367 #define xchg8(a, v, ...) \
 368 ({  uint32_t o;                \
 369     asm volatile(              \
 370         "swpb %0, %1, [%2]"    \
 371         : "=&r"(o)             \
 372         : "r"(v),              \
 373           "r"((uint8_t*)(a))); \
 374     o; })
 375 /* atomic */
 376 #define xchg32(a, v, ...) \
 377 ({  uint32_t o;                 \
 378     asm volatile(               \
 379         "swp %0, %1, [%2]"      \
 380         : "=&r"(o)              \
 381         : "r"((uint32_t)(v)),   \
 382           "r"((uint32_t*)(a))); \
 383     o; })
 384 /* atomic */
 385 #define xchgptr(a, v, ...) \
 386 ({  typeof (*(a)) o;        \
 387     asm volatile(           \
 388         "swp %0, %1, [%2]"  \
 389         : "=&r"(o)          \
 390         : "r"(v), "r"(a));  \
 391     o; })
 392 #endif /* locking selection */
 393 #elif defined (CPU_COLDFIRE)
 394 /* atomic */
 395 /* one branch will be optimized away if v is a constant expression */
 396 #define test_and_set(a, v, ...) \
 397 ({  uint32_t o = 0;                \
 398     if (v) {                       \
 399         asm volatile (             \
 400             "bset.b #0, (%0)"      \
 401             : : "a"((uint8_t*)(a)) \
 402             : "cc");               \
 403     } else {                       \
 404         asm volatile (             \
 405             "bclr.b #0, (%0)"      \
 406             : : "a"((uint8_t*)(a)) \
 407             : "cc");               \
 408     }                              \
 409     asm volatile ("sne.b %0"       \
 410         : "+d"(o));                \
 411     o; })
 412 #elif CONFIG_CPU == SH7034
 413 /* atomic */
 414 #define test_and_set(a, v, ...) \
 415 ({  uint32_t o;                 \
 416     asm volatile (              \
 417         "tas.b  @%2     \n"     \
 418         "mov    #-1, %0 \n"     \
 419         "negc   %0, %0  \n"     \
 420         : "=r"(o)               \
 421         : "M"((uint32_t)(v)),   /* Value of_v must be 1 */ \
 422           "r"((uint8_t *)(a))); \
 423     o; })
 424 #endif /* CONFIG_CPU == */
 425
 426 /* defaults for no asm version */
 427 #ifndef test_and_set
 428 /* not atomic */
 429 #define test_and_set(a, v, ...) \
 430 ({  uint32_t o = *(uint8_t *)(a); \
 431     *(uint8_t *)(a) = (v);        \
 432     o; })
 433 #endif /* test_and_set */
 434 #ifndef xchg8
 435 /* not atomic */
 436 #define xchg8(a, v, ...) \
 437 ({  uint32_t o = *(uint8_t *)(a); \
 438     *(uint8_t *)(a) = (v);        \
 439     o; })
 440 #endif /* xchg8 */
 441 #ifndef xchg32
 442 /* not atomic */
 443 #define xchg32(a, v, ...) \
 444 ({  uint32_t o = *(uint32_t *)(a); \
 445     *(uint32_t *)(a) = (v);        \
 446     o; })
 447 #endif /* xchg32 */
 448 #ifndef xchgptr
 449 /* not atomic */
 450 #define xchgptr(a, v, ...) \
 451 ({  typeof (*(a)) o = *(a); \
 452     *(a) = (v);             \
 453     o; })
 454 #endif /* xchgptr */
 455
 456 void core_idle(void);
 457 void core_wake(IF_COP_VOID(unsigned int core));
 458
 459 /* Initialize the scheduler */
 460 void init_threads(void);
 461
 462 /* Allocate a thread in the scheduler */
 463 #define CREATE_THREAD_FROZEN   0x00000001 /* Thread is frozen at create time */
 464 struct thread_entry*
 465     create_thread(void (*function)(void), void* stack, size_t stack_size,
 466                   unsigned flags, const char *name
 467                   IF_PRIO(, int priority)
 468                           IF_COP(, unsigned int core));
 469
 470 /* Set and clear the CPU frequency boost flag for the calling thread */
 471 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 472 void trigger_cpu_boost(void);
 473 void cancel_cpu_boost(void);
 474 #else
 475 #define trigger_cpu_boost()
 476 #define cancel_cpu_boost()
 477 #endif
 478 /* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
 479  * Has no effect on a thread not frozen. */
 480 void thread_thaw(struct thread_entry *thread);
 481 /* Wait for a thread to exit */
 482 void thread_wait(struct thread_entry *thread);
 483 /* Exit the current thread */
 484 void thread_exit(void);
 485 #if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
 486 #define ALLOW_REMOVE_THREAD
 487 /* Remove a thread from the scheduler */
 488 void remove_thread(struct thread_entry *thread);
 489 #endif
 490
 491 /* Switch to next runnable thread */
 492 void switch_thread(void);
 493 /* Blocks a thread for at least the specified number of ticks (0 = wait until
 494  * next tick) */
 495 void sleep_thread(int ticks);
 496 /* Indefinitely blocks the current thread on a thread queue */
 497 void block_thread(struct thread_entry *current);
 498 /* Blocks the current thread on a thread queue until explicitely woken or
 499  * the timeout is reached */
 500 void block_thread_w_tmo(struct thread_entry *current, int timeout);
 501
 502 /* Return bit flags for thread wakeup */
 503 #define THREAD_NONE     0x0 /* No thread woken up (exclusive) */
 504 #define THREAD_OK       0x1 /* A thread was woken up */
 505 #define THREAD_SWITCH   0x2 /* Task switch recommended (one or more of
 506                                higher priority than current were woken) */
 507
 508 /* A convenience function for waking an entire queue of threads. */
 509 unsigned int thread_queue_wake(struct thread_entry **list);
 510
 511 /* Wakeup a thread at the head of a list */
 512 unsigned int wakeup_thread(struct thread_entry **list);
 513
 514 #ifdef HAVE_PRIORITY_SCHEDULING
 515 int thread_set_priority(struct thread_entry *thread, int priority);
 516 int thread_get_priority(struct thread_entry *thread);
 517 #endif /* HAVE_PRIORITY_SCHEDULING */
 518 #if NUM_CORES > 1
 519 unsigned int switch_core(unsigned int new_core);
 520 #endif
 521 struct thread_entry * thread_get_current(void);
 522
 523 /* Debugging info - only! */
 524 int thread_stack_usage(const struct thread_entry *thread);
 525 #if NUM_CORES > 1
 526 int idle_stack_usage(unsigned int core);
 527 #endif
 528 void thread_get_name(char *buffer, int size,
 529                      struct thread_entry *thread);
 530 #ifdef RB_PROFILE
 531 void profile_thread(void);
 532 #endif
 533
 534 #endif /* THREAD_H */