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  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #ifndef THREAD_H
  22 #define THREAD_H
  23
  24 #include "config.h"
  25 #include <inttypes.h>
  26 #include <stddef.h>
  27 #include <stdbool.h>
  28
  29 /* Priority scheduling (when enabled with HAVE_PRIORITY_SCHEDULING) works
  30  * by giving high priority threads more CPU time than lower priority threads
  31  * when they need it. Priority is differential such that the priority
  32  * difference between a lower priority runnable thread and the highest priority
  33  * runnable thread determines the amount of aging necessary for the lower
  34  * priority thread to be scheduled in order to prevent starvation.
  35  *
  36  * If software playback codec pcm buffer is going down to critical, codec
  37  * can gradually raise its own priority to override user interface and
  38  * prevent playback skipping.
  39  */
  40 #define PRIORITY_RESERVED_HIGH   0   /* Reserved */
  41 #define PRIORITY_RESERVED_LOW    32  /* Reserved */
  42 #define HIGHEST_PRIORITY         1   /* The highest possible thread priority */
  43 #define LOWEST_PRIORITY          31  /* The lowest possible thread priority */
  44 /* Realtime range reserved for threads that will not allow threads of lower
  45  * priority to age and run (future expansion) */
  46 #define PRIORITY_REALTIME_1      1
  47 #define PRIORITY_REALTIME_2      2
  48 #define PRIORITY_REALTIME_3      3
  49 #define PRIORITY_REALTIME_4      4
  50 #define PRIORITY_REALTIME        4   /* Lowest realtime range */
  51 #define PRIORITY_BUFFERING       15  /* Codec buffering thread */
  52 #define PRIORITY_USER_INTERFACE  16  /* The main thread */
  53 #define PRIORITY_RECORDING       16  /* Recording thread */
  54 #define PRIORITY_PLAYBACK        16  /* Variable between this and MAX */
  55 #define PRIORITY_PLAYBACK_MAX    5   /* Maximum allowable playback priority */
  56 #define PRIORITY_SYSTEM          18  /* All other firmware threads */
  57 #define PRIORITY_BACKGROUND      20  /* Normal application threads */
  58 #define NUM_PRIORITIES           32
  59 #define PRIORITY_IDLE            32  /* Priority representative of no tasks */
  60
  61 /* TODO: Only a minor tweak to create_thread would be needed to let
  62  * thread slots be caller allocated - no essential threading functionality
  63  * depends upon an array */
  64 #if CONFIG_CODEC == SWCODEC
  65
  66 #ifdef HAVE_RECORDING
  67 #define BASETHREADS  18
  68 #else
  69 #define BASETHREADS  17
  70 #endif
  71
  72 #else
  73 #define BASETHREADS  11
  74 #endif /* CONFIG_CODE == * */
  75
  76 #ifndef TARGET_EXTRA_THREADS
  77 #define TARGET_EXTRA_THREADS 0
  78 #endif
  79
  80 #define MAXTHREADS (BASETHREADS+TARGET_EXTRA_THREADS)
  81
  82 #define DEFAULT_STACK_SIZE 0x400 /* Bytes */
  83
  84 #ifndef SIMULATOR
  85 /* Need to keep structures inside the header file because debug_menu
  86  * needs them. */
  87 #ifdef CPU_COLDFIRE
  88 struct regs
  89 {
  90     uint32_t macsr; /*     0 - EMAC status register */
  91     uint32_t d[6];  /*  4-24 - d2-d7 */
  92     uint32_t a[5];  /* 28-44 - a2-a6 */
  93     uint32_t sp;    /*    48 - Stack pointer (a7) */
  94     uint32_t start; /*    52 - Thread start address, or NULL when started */
  95 };
  96 #elif CONFIG_CPU == SH7034
  97 struct regs
  98 {
  99     uint32_t r[7];  /*  0-24 - Registers r8 thru r14 */
 100     uint32_t sp;    /*    28 - Stack pointer (r15) */
 101     uint32_t pr;    /*    32 - Procedure register */
 102     uint32_t start; /*    36 - Thread start address, or NULL when started */
 103 };
 104 #elif defined(CPU_ARM)
 105 struct regs
 106 {
 107     uint32_t r[8];  /*  0-28 - Registers r4-r11 */
 108     uint32_t sp;    /*    32 - Stack pointer (r13) */
 109     uint32_t lr;    /*    36 - r14 (lr) */
 110     uint32_t start; /*    40 - Thread start address, or NULL when started */
 111 };
 112 #endif /* CONFIG_CPU */
 113 #else
 114 struct regs
 115 {
 116     void *t;             /* Simulator OS thread */
 117     void *s;             /* Semaphore for blocking and wakeup */
 118     void (*start)(void); /* Start function */
 119 };
 120 #endif /* !SIMULATOR */
 121
 122 /* NOTE: The use of the word "queue" may also refer to a linked list of
 123    threads being maintained that are normally dealt with in FIFO order
 124    and not necessarily kernel event_queue */
 125 enum
 126 {
 127     /* States without a timeout must be first */
 128     STATE_KILLED = 0,    /* Thread is killed (default) */
 129     STATE_RUNNING,       /* Thread is currently running */
 130     STATE_BLOCKED,       /* Thread is indefinitely blocked on a queue */
 131     /* These states involve adding the thread to the tmo list */
 132     STATE_SLEEPING,      /* Thread is sleeping with a timeout */
 133     STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
 134     /* Miscellaneous states */
 135     STATE_FROZEN,        /* Thread is suspended and will not run until
 136                             thread_thaw is called with its ID */
 137     THREAD_NUM_STATES,
 138     TIMEOUT_STATE_FIRST = STATE_SLEEPING,
 139 };
 140
 141 #if NUM_CORES > 1
 142 /* Pointer value for name field to indicate thread is being killed. Using
 143  * an alternate STATE_* won't work since that would interfere with operation
 144  * while the thread is still running. */
 145 #define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
 146 #endif
 147
 148 /* Link information for lists thread is in */
 149 struct thread_entry; /* forward */
 150 struct thread_list
 151 {
 152     struct thread_entry *prev; /* Previous thread in a list */
 153     struct thread_entry *next; /* Next thread in a list */
 154 };
 155
 156 /* Small objects for core-wise mutual exclusion */
 157 #if CONFIG_CORELOCK == SW_CORELOCK
 158 /* No reliable atomic instruction available - use Peterson's algorithm */
 159 struct corelock
 160 {
 161     volatile unsigned char myl[NUM_CORES];
 162     volatile unsigned char turn;
 163 } __attribute__((packed));
 164
 165 void corelock_init(struct corelock *cl);
 166 void corelock_lock(struct corelock *cl);
 167 int corelock_try_lock(struct corelock *cl);
 168 void corelock_unlock(struct corelock *cl);
 169 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 170 /* Use native atomic swap/exchange instruction */
 171 struct corelock
 172 {
 173     volatile unsigned char locked;
 174 } __attribute__((packed));
 175
 176 #define corelock_init(cl) \
 177     ({ (cl)->locked = 0; })
 178 #define corelock_lock(cl) \
 179     ({ while (test_and_set(&(cl)->locked, 1)); })
 180 #define corelock_try_lock(cl) \
 181     ({ test_and_set(&(cl)->locked, 1) ? 0 : 1; })
 182 #define corelock_unlock(cl) \
 183     ({ (cl)->locked = 0; })
 184 #else
 185 /* No atomic corelock op needed or just none defined */
 186 #define corelock_init(cl)
 187 #define corelock_lock(cl)
 188 #define corelock_try_lock(cl)
 189 #define corelock_unlock(cl)
 190 #endif /* core locking selection */
 191
 192 #ifdef HAVE_PRIORITY_SCHEDULING
 193 struct blocker
 194 {
 195     struct thread_entry *thread;   /* thread blocking other threads
 196                                       (aka. object owner) */
 197     int priority;                  /* highest priority waiter */
 198     struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
 199 };
 200
 201 /* Choices of wakeup protocol */
 202
 203 /* For transfer of object ownership by one thread to another thread by
 204  * the owning thread itself (mutexes) */
 205 struct thread_entry *
 206     wakeup_priority_protocol_transfer(struct thread_entry *thread);
 207
 208 /* For release by owner where ownership doesn't change - other threads,
 209  * interrupts, timeouts, etc. (mutex timeout, queues) */
 210 struct thread_entry *
 211     wakeup_priority_protocol_release(struct thread_entry *thread);
 212
 213
 214 struct priority_distribution
 215 {
 216     uint8_t  hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
 217     uint32_t mask;                 /* Bitmask of hist entries that are not zero */
 218 };
 219
 220 #endif /* HAVE_PRIORITY_SCHEDULING */
 221
 222 /* Information kept in each thread slot
 223  * members are arranged according to size - largest first - in order
 224  * to ensure both alignment and packing at the same time.
 225  */
 226 struct thread_entry
 227 {
 228     struct regs context;       /* Register context at switch -
 229                                   _must_ be first member */
 230     uintptr_t *stack;          /* Pointer to top of stack */
 231     const char *name;          /* Thread name */
 232     long tmo_tick;             /* Tick when thread should be woken from
 233                                   timeout -
 234                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 235     struct thread_list l;      /* Links for blocked/waking/running -
 236                                   circular linkage in both directions */
 237     struct thread_list tmo;    /* Links for timeout list -
 238                                   Circular in reverse direction, NULL-terminated in
 239                                   forward direction -
 240                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 241     struct thread_entry **bqp; /* Pointer to list variable in kernel
 242                                   object where thread is blocked - used
 243                                   for implicit unblock and explicit wake
 244                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 245 #if NUM_CORES > 1
 246     struct corelock *obj_cl;   /* Object corelock where thead is blocked -
 247                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
 248 #endif
 249     struct thread_entry *queue; /* List of threads waiting for thread to be
 250                                   removed */
 251 #ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
 252     #define HAVE_WAKEUP_EXT_CB
 253     void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
 254                                   performs special steps needed when being
 255                                   forced off of an object's wait queue that
 256                                   go beyond the standard wait queue removal
 257                                   and priority disinheritance */
 258     /* Only enabled when using queue_send for now */
 259 #endif
 260 #if defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || NUM_CORES > 1
 261     intptr_t retval;           /* Return value from a blocked operation/
 262                                   misc. use */
 263 #endif
 264 #ifdef HAVE_PRIORITY_SCHEDULING
 265     /* Priority summary of owned objects that support inheritance */
 266     struct blocker *blocker;   /* Pointer to blocker when this thread is blocked
 267                                   on an object that supports PIP -
 268                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 269     struct priority_distribution pdist; /* Priority summary of owned objects
 270                                   that have blocked threads and thread's own
 271                                   base priority */
 272     int skip_count;            /* Number of times skipped if higher priority
 273                                   thread was running */
 274 #endif
 275     unsigned short stack_size; /* Size of stack in bytes */
 276 #ifdef HAVE_PRIORITY_SCHEDULING
 277     unsigned char base_priority; /* Base priority (set explicitly during
 278                                   creation or thread_set_priority) */
 279     unsigned char priority;    /* Scheduled priority (higher of base or
 280                                   all threads blocked by this one) */
 281 #endif
 282     unsigned char state;       /* Thread slot state (STATE_*) */
 283 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 284     unsigned char cpu_boost;   /* CPU frequency boost flag */
 285 #endif
 286 #if NUM_CORES > 1
 287     unsigned char core;        /* The core to which thread belongs */
 288     struct corelock waiter_cl; /* Corelock for thread_wait */
 289     struct corelock slot_cl;   /* Corelock to lock thread slot */
 290 #endif
 291 };
 292
 293 #if NUM_CORES > 1
 294 /* Operations to be performed just before stopping a thread and starting
 295    a new one if specified before calling switch_thread */
 296 enum
 297 {
 298     TBOP_CLEAR = 0,       /* No operation to do */
 299     TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
 300     TBOP_SWITCH_CORE,     /* Call the core switch preparation routine */
 301 };
 302
 303 struct thread_blk_ops
 304 {
 305     struct corelock *cl_p;    /* pointer to corelock */
 306     unsigned char    flags;   /* TBOP_* flags */
 307 };
 308 #endif /* NUM_CORES > 1 */
 309
 310 /* Information kept for each core
 311  * Members are arranged for the same reason as in thread_entry
 312  */
 313 struct core_entry
 314 {
 315     /* "Active" lists - core is constantly active on these and are never
 316        locked and interrupts do not access them */
 317     struct thread_entry *running;  /* threads that are running (RTR) */
 318     struct thread_entry *timeout;  /* threads that are on a timeout before
 319                                       running again */
 320     struct thread_entry *block_task; /* Task going off running list */
 321 #ifdef HAVE_PRIORITY_SCHEDULING
 322     struct priority_distribution rtr; /* Summary of running and ready-to-run
 323                                          threads */
 324 #endif
 325     long next_tmo_check;           /* soonest time to check tmo threads */
 326 #if NUM_CORES > 1
 327     struct thread_blk_ops blk_ops; /* operations to perform when
 328                                       blocking a thread */
 329     struct corelock rtr_cl;        /* Lock for rtr list */
 330 #endif /* NUM_CORES */
 331 };
 332
 333 #ifdef HAVE_PRIORITY_SCHEDULING
 334 #define IF_PRIO(...)    __VA_ARGS__
 335 #define IFN_PRIO(...)
 336 #else
 337 #define IF_PRIO(...)
 338 #define IFN_PRIO(...)   __VA_ARGS__
 339 #endif
 340
 341 /* Macros generate better code than an inline function is this case */
 342 #if (defined (CPU_PP) || defined (CPU_ARM))
 343 /* atomic */
 344 #if CONFIG_CORELOCK == SW_CORELOCK
 345 #define test_and_set(a, v, cl) \
 346     xchg8((a), (v), (cl))
 347 /* atomic */
 348 #define xchg8(a, v, cl) \
 349 ({  uint32_t o;            \
 350     corelock_lock(cl);     \
 351     o = *(uint8_t *)(a);   \
 352     *(uint8_t *)(a) = (v); \
 353     corelock_unlock(cl);   \
 354     o; })
 355 #define xchg32(a, v, cl) \
 356 ({  uint32_t o;             \
 357     corelock_lock(cl);      \
 358     o = *(uint32_t *)(a);   \
 359     *(uint32_t *)(a) = (v); \
 360     corelock_unlock(cl);    \
 361     o; })
 362 #define xchgptr(a, v, cl) \
 363 ({  typeof (*(a)) o;     \
 364     corelock_lock(cl);   \
 365     o = *(a);            \
 366     *(a) = (v);          \
 367     corelock_unlock(cl); \
 368     o; })
 369 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 370 /* atomic */
 371 #define test_and_set(a, v, ...) \
 372     xchg8((a), (v))
 373 #define xchg8(a, v, ...) \
 374 ({  uint32_t o;                \
 375     asm volatile(              \
 376         "swpb %0, %1, [%2]"    \
 377         : "=&r"(o)             \
 378         : "r"(v),              \
 379           "r"((uint8_t*)(a))); \
 380     o; })
 381 /* atomic */
 382 #define xchg32(a, v, ...) \
 383 ({  uint32_t o;                 \
 384     asm volatile(               \
 385         "swp %0, %1, [%2]"      \
 386         : "=&r"(o)              \
 387         : "r"((uint32_t)(v)),   \
 388           "r"((uint32_t*)(a))); \
 389     o; })
 390 /* atomic */
 391 #define xchgptr(a, v, ...) \
 392 ({  typeof (*(a)) o;        \
 393     asm volatile(           \
 394         "swp %0, %1, [%2]"  \
 395         : "=&r"(o)          \
 396         : "r"(v), "r"(a));  \
 397     o; })
 398 #endif /* locking selection */
 399 #elif defined (CPU_COLDFIRE)
 400 /* atomic */
 401 /* one branch will be optimized away if v is a constant expression */
 402 #define test_and_set(a, v, ...) \
 403 ({  uint32_t o = 0;                \
 404     if (v) {                       \
 405         asm volatile (             \
 406             "bset.b #0, (%0)"      \
 407             : : "a"((uint8_t*)(a)) \
 408             : "cc");               \
 409     } else {                       \
 410         asm volatile (             \
 411             "bclr.b #0, (%0)"      \
 412             : : "a"((uint8_t*)(a)) \
 413             : "cc");               \
 414     }                              \
 415     asm volatile ("sne.b %0"       \
 416         : "+d"(o));                \
 417     o; })
 418 #elif CONFIG_CPU == SH7034
 419 /* atomic */
 420 #define test_and_set(a, v, ...) \
 421 ({  uint32_t o;                 \
 422     asm volatile (              \
 423         "tas.b  @%2     \n"     \
 424         "mov    #-1, %0 \n"     \
 425         "negc   %0, %0  \n"     \
 426         : "=r"(o)               \
 427         : "M"((uint32_t)(v)),   /* Value of_v must be 1 */ \
 428           "r"((uint8_t *)(a))); \
 429     o; })
 430 #endif /* CONFIG_CPU == */
 431
 432 /* defaults for no asm version */
 433 #ifndef test_and_set
 434 /* not atomic */
 435 #define test_and_set(a, v, ...) \
 436 ({  uint32_t o = *(uint8_t *)(a); \
 437     *(uint8_t *)(a) = (v);        \
 438     o; })
 439 #endif /* test_and_set */
 440 #ifndef xchg8
 441 /* not atomic */
 442 #define xchg8(a, v, ...) \
 443 ({  uint32_t o = *(uint8_t *)(a); \
 444     *(uint8_t *)(a) = (v);        \
 445     o; })
 446 #endif /* xchg8 */
 447 #ifndef xchg32
 448 /* not atomic */
 449 #define xchg32(a, v, ...) \
 450 ({  uint32_t o = *(uint32_t *)(a); \
 451     *(uint32_t *)(a) = (v);        \
 452     o; })
 453 #endif /* xchg32 */
 454 #ifndef xchgptr
 455 /* not atomic */
 456 #define xchgptr(a, v, ...) \
 457 ({  typeof (*(a)) o = *(a); \
 458     *(a) = (v);             \
 459     o; })
 460 #endif /* xchgptr */
 461
 462 void core_idle(void);
 463 void core_wake(IF_COP_VOID(unsigned int core));
 464
 465 /* Initialize the scheduler */
 466 void init_threads(void);
 467
 468 /* Allocate a thread in the scheduler */
 469 #define CREATE_THREAD_FROZEN   0x00000001 /* Thread is frozen at create time */
 470 struct thread_entry*
 471     create_thread(void (*function)(void), void* stack, size_t stack_size,
 472                   unsigned flags, const char *name
 473                   IF_PRIO(, int priority)
 474                           IF_COP(, unsigned int core));
 475
 476 /* Set and clear the CPU frequency boost flag for the calling thread */
 477 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 478 void trigger_cpu_boost(void);
 479 void cancel_cpu_boost(void);
 480 #else
 481 #define trigger_cpu_boost()
 482 #define cancel_cpu_boost()
 483 #endif
 484 /* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
 485  * Has no effect on a thread not frozen. */
 486 void thread_thaw(struct thread_entry *thread);
 487 /* Wait for a thread to exit */
 488 void thread_wait(struct thread_entry *thread);
 489 /* Exit the current thread */
 490 void thread_exit(void);
 491 #if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
 492 #define ALLOW_REMOVE_THREAD
 493 /* Remove a thread from the scheduler */
 494 void remove_thread(struct thread_entry *thread);
 495 #endif
 496
 497 /* Switch to next runnable thread */
 498 void switch_thread(void);
 499 /* Blocks a thread for at least the specified number of ticks (0 = wait until
 500  * next tick) */
 501 void sleep_thread(int ticks);
 502 /* Indefinitely blocks the current thread on a thread queue */
 503 void block_thread(struct thread_entry *current);
 504 /* Blocks the current thread on a thread queue until explicitely woken or
 505  * the timeout is reached */
 506 void block_thread_w_tmo(struct thread_entry *current, int timeout);
 507
 508 /* Return bit flags for thread wakeup */
 509 #define THREAD_NONE     0x0 /* No thread woken up (exclusive) */
 510 #define THREAD_OK       0x1 /* A thread was woken up */
 511 #define THREAD_SWITCH   0x2 /* Task switch recommended (one or more of
 512                                higher priority than current were woken) */
 513
 514 /* A convenience function for waking an entire queue of threads. */
 515 unsigned int thread_queue_wake(struct thread_entry **list);
 516
 517 /* Wakeup a thread at the head of a list */
 518 unsigned int wakeup_thread(struct thread_entry **list);
 519
 520 #ifdef HAVE_PRIORITY_SCHEDULING
 521 int thread_set_priority(struct thread_entry *thread, int priority);
 522 int thread_get_priority(struct thread_entry *thread);
 523 #endif /* HAVE_PRIORITY_SCHEDULING */
 524 #if NUM_CORES > 1
 525 unsigned int switch_core(unsigned int new_core);
 526 #endif
 527 struct thread_entry * thread_get_current(void);
 528
 529 /* Debugging info - only! */
 530 int thread_stack_usage(const struct thread_entry *thread);
 531 #if NUM_CORES > 1
 532 int idle_stack_usage(unsigned int core);
 533 #endif
 534 void thread_get_name(char *buffer, int size,
 535                      struct thread_entry *thread);
 536 #ifdef RB_PROFILE
 537 void profile_thread(void);
 538 #endif
 539
 540 #endif /* THREAD_H */