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 #include "gcc_extensions.h"
  29
  30 /* Priority scheduling (when enabled with HAVE_PRIORITY_SCHEDULING) works
  31  * by giving high priority threads more CPU time than lower priority threads
  32  * when they need it. Priority is differential such that the priority
  33  * difference between a lower priority runnable thread and the highest priority
  34  * runnable thread determines the amount of aging necessary for the lower
  35  * priority thread to be scheduled in order to prevent starvation.
  36  *
  37  * If software playback codec pcm buffer is going down to critical, codec
  38  * can gradually raise its own priority to override user interface and
  39  * prevent playback skipping.
  40  */
  41 #define PRIORITY_RESERVED_HIGH   0   /* Reserved */
  42 #define PRIORITY_RESERVED_LOW    32  /* Reserved */
  43 #define HIGHEST_PRIORITY         1   /* The highest possible thread priority */
  44 #define LOWEST_PRIORITY          31  /* The lowest possible thread priority */
  45 /* Realtime range reserved for threads that will not allow threads of lower
  46  * priority to age and run (future expansion) */
  47 #define PRIORITY_REALTIME_1      1
  48 #define PRIORITY_REALTIME_2      2
  49 #define PRIORITY_REALTIME_3      3
  50 #define PRIORITY_REALTIME_4      4
  51 #define PRIORITY_REALTIME        4   /* Lowest realtime range */
  52 #define PRIORITY_BUFFERING       15  /* Codec buffering thread */
  53 #define PRIORITY_USER_INTERFACE  16  /* The main thread */
  54 #define PRIORITY_RECORDING       16  /* Recording thread */
  55 #define PRIORITY_PLAYBACK        16  /* Variable between this and MAX */
  56 #define PRIORITY_PLAYBACK_MAX    5   /* Maximum allowable playback priority */
  57 #define PRIORITY_SYSTEM          18  /* All other firmware threads */
  58 #define PRIORITY_BACKGROUND      20  /* Normal application threads */
  59 #define NUM_PRIORITIES           32
  60 #define PRIORITY_IDLE            32  /* Priority representative of no tasks */
  61
  62 #define IO_PRIORITY_IMMEDIATE    0
  63 #define IO_PRIORITY_BACKGROUND   32
  64
  65 #if CONFIG_CODEC == SWCODEC
  66
  67 #ifdef HAVE_RECORDING
  68 #define BASETHREADS  17
  69 #else
  70 #define BASETHREADS  16
  71 #endif
  72
  73 #else
  74 #define BASETHREADS  11
  75 #endif /* CONFIG_CODE == * */
  76
  77 #ifndef TARGET_EXTRA_THREADS
  78 #define TARGET_EXTRA_THREADS 0
  79 #endif
  80
  81 #define MAXTHREADS (BASETHREADS+TARGET_EXTRA_THREADS)
  82
  83 /*
  84  * We need more stack when we run under a host
  85  * maybe more expensive C lib functions?
  86  *
  87  * simulator (possibly) doesn't simulate stack usage anyway but well ... */
  88 #ifdef HAVE_SIGALTSTACK_THREADS
  89 #include <signal.h>
  90 /* MINSIGSTKSZ for the OS to deliver the signal + 0x3000 for us */
  91 #define DEFAULT_STACK_SIZE (MINSIGSTKSZ+0x3000) /* Bytes */
  92 #elif (CONFIG_PLATFORM & PLATFORM_ANDROID) || defined(HAVE_WIN32_FIBER_THREADS)
  93 #define DEFAULT_STACK_SIZE 0x1000 /* Bytes */
  94 #else /* native threads, sdl threads */
  95 #define DEFAULT_STACK_SIZE 0x400 /* Bytes */
  96 #endif
  97
  98
  99 #if defined(ASSEMBLER_THREADS)
 100 /* Need to keep structures inside the header file because debug_menu
 101  * needs them. */
 102 #ifdef CPU_COLDFIRE
 103 struct regs
 104 {
 105     uint32_t macsr; /*     0 - EMAC status register */
 106     uint32_t d[6];  /*  4-24 - d2-d7 */
 107     uint32_t a[5];  /* 28-44 - a2-a6 */
 108     uint32_t sp;    /*    48 - Stack pointer (a7) */
 109     uint32_t start; /*    52 - Thread start address, or NULL when started */
 110 };
 111 #elif CONFIG_CPU == SH7034
 112 struct regs
 113 {
 114     uint32_t r[7];  /*  0-24 - Registers r8 thru r14 */
 115     uint32_t sp;    /*    28 - Stack pointer (r15) */
 116     uint32_t pr;    /*    32 - Procedure register */
 117     uint32_t start; /*    36 - Thread start address, or NULL when started */
 118 };
 119 #elif defined(CPU_ARM)
 120 struct regs
 121 {
 122     uint32_t r[8];  /*  0-28 - Registers r4-r11 */
 123     uint32_t sp;    /*    32 - Stack pointer (r13) */
 124     uint32_t lr;    /*    36 - r14 (lr) */
 125     uint32_t start; /*    40 - Thread start address, or NULL when started */
 126 };
 127
 128 #elif defined(CPU_MIPS)
 129 struct regs
 130 {
 131     uint32_t r[9];  /* 0-32 - Registers s0-s7, fp */
 132     uint32_t sp;    /*   36 - Stack pointer */
 133     uint32_t ra;    /*   40 - Return address */
 134     uint32_t start; /*   44 - Thread start address, or NULL when started */
 135 };
 136 #endif /* CONFIG_CPU */
 137 #elif (CONFIG_PLATFORM & PLATFORM_HOSTED) || defined(__PCTOOL__)
 138 #ifndef HAVE_SDL_THREADS
 139 struct regs
 140 {
 141     void (*start)(void); /* thread's entry point, or NULL when started */
 142     void* uc;            /* host thread handle */
 143     uintptr_t sp;        /* Stack pointer, unused */
 144     size_t stack_size;   /* stack size, not always used */
 145     uintptr_t stack;     /* pointer to start of the stack buffer */
 146 };
 147 #else /* SDL threads */
 148 struct regs
 149 {
 150     void *t;             /* OS thread */
 151     void *told;          /* Last thread in slot (explained in thead-sdl.c) */
 152     void *s;             /* Semaphore for blocking and wakeup */
 153     void (*start)(void); /* Start function */
 154 };
 155 #endif
 156 #endif /* PLATFORM_NATIVE */
 157
 158 #ifdef CPU_PP
 159 #ifdef HAVE_CORELOCK_OBJECT
 160 /* No reliable atomic instruction available - use Peterson's algorithm */
 161 struct corelock
 162 {
 163     volatile unsigned char myl[NUM_CORES];
 164     volatile unsigned char turn;
 165 } __attribute__((packed));
 166
 167 /* Too big to inline everywhere */
 168 void corelock_init(struct corelock *cl);
 169 void corelock_lock(struct corelock *cl);
 170 int corelock_try_lock(struct corelock *cl);
 171 void corelock_unlock(struct corelock *cl);
 172 #endif /* HAVE_CORELOCK_OBJECT */
 173 #endif /* CPU_PP */
 174
 175 /* NOTE: The use of the word "queue" may also refer to a linked list of
 176    threads being maintained that are normally dealt with in FIFO order
 177    and not necessarily kernel event_queue */
 178 enum
 179 {
 180     /* States without a timeout must be first */
 181     STATE_KILLED = 0,    /* Thread is killed (default) */
 182     STATE_RUNNING,       /* Thread is currently running */
 183     STATE_BLOCKED,       /* Thread is indefinitely blocked on a queue */
 184     /* These states involve adding the thread to the tmo list */
 185     STATE_SLEEPING,      /* Thread is sleeping with a timeout */
 186     STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
 187     /* Miscellaneous states */
 188     STATE_FROZEN,        /* Thread is suspended and will not run until
 189                             thread_thaw is called with its ID */
 190     THREAD_NUM_STATES,
 191     TIMEOUT_STATE_FIRST = STATE_SLEEPING,
 192 };
 193
 194 #if NUM_CORES > 1
 195 /* Pointer value for name field to indicate thread is being killed. Using
 196  * an alternate STATE_* won't work since that would interfere with operation
 197  * while the thread is still running. */
 198 #define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
 199 #endif
 200
 201 /* Link information for lists thread is in */
 202 struct thread_entry; /* forward */
 203 struct thread_list
 204 {
 205     struct thread_entry *prev; /* Previous thread in a list */
 206     struct thread_entry *next; /* Next thread in a list */
 207 };
 208
 209 #ifndef HAVE_CORELOCK_OBJECT
 210 /* No atomic corelock op needed or just none defined */
 211 #define corelock_init(cl)
 212 #define corelock_lock(cl)
 213 #define corelock_try_lock(cl)
 214 #define corelock_unlock(cl)
 215 #endif /* HAVE_CORELOCK_OBJECT */
 216
 217 #ifdef HAVE_PRIORITY_SCHEDULING
 218 struct blocker
 219 {
 220     struct thread_entry * volatile thread; /* thread blocking other threads
 221                                               (aka. object owner) */
 222     int priority;                  /* highest priority waiter */
 223     struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
 224 };
 225
 226 /* Choices of wakeup protocol */
 227
 228 /* For transfer of object ownership by one thread to another thread by
 229  * the owning thread itself (mutexes) */
 230 struct thread_entry *
 231     wakeup_priority_protocol_transfer(struct thread_entry *thread);
 232
 233 /* For release by owner where ownership doesn't change - other threads,
 234  * interrupts, timeouts, etc. (mutex timeout, queues) */
 235 struct thread_entry *
 236     wakeup_priority_protocol_release(struct thread_entry *thread);
 237
 238
 239 struct priority_distribution
 240 {
 241     uint8_t  hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
 242     uint32_t mask;                 /* Bitmask of hist entries that are not zero */
 243 };
 244
 245 #endif /* HAVE_PRIORITY_SCHEDULING */
 246
 247 /* Information kept in each thread slot
 248  * members are arranged according to size - largest first - in order
 249  * to ensure both alignment and packing at the same time.
 250  */
 251 struct thread_entry
 252 {
 253     struct regs context;       /* Register context at switch -
 254                                   _must_ be first member */
 255     uintptr_t *stack;          /* Pointer to top of stack */
 256     const char *name;          /* Thread name */
 257     long tmo_tick;             /* Tick when thread should be woken from
 258                                   timeout -
 259                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 260     struct thread_list l;      /* Links for blocked/waking/running -
 261                                   circular linkage in both directions */
 262     struct thread_list tmo;    /* Links for timeout list -
 263                                   Circular in reverse direction, NULL-terminated in
 264                                   forward direction -
 265                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 266     struct thread_entry **bqp; /* Pointer to list variable in kernel
 267                                   object where thread is blocked - used
 268                                   for implicit unblock and explicit wake
 269                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 270 #ifdef HAVE_CORELOCK_OBJECT
 271     struct corelock *obj_cl;   /* Object corelock where thead is blocked -
 272                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
 273     struct corelock waiter_cl; /* Corelock for thread_wait */
 274     struct corelock slot_cl;   /* Corelock to lock thread slot */
 275     unsigned char core;        /* The core to which thread belongs */
 276 #endif
 277     struct thread_entry *queue; /* List of threads waiting for thread to be
 278                                   removed */
 279 #ifdef HAVE_WAKEUP_EXT_CB
 280     void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
 281                                   performs special steps needed when being
 282                                   forced off of an object's wait queue that
 283                                   go beyond the standard wait queue removal
 284                                   and priority disinheritance */
 285     /* Only enabled when using queue_send for now */
 286 #endif
 287 #if defined(HAVE_SEMAPHORE_OBJECTS) || \
 288     defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || \
 289     NUM_CORES > 1
 290     volatile intptr_t retval;  /* Return value from a blocked operation/
 291                                   misc. use */
 292 #endif
 293 #ifdef HAVE_PRIORITY_SCHEDULING
 294     /* Priority summary of owned objects that support inheritance */
 295     struct blocker *blocker;   /* Pointer to blocker when this thread is blocked
 296                                   on an object that supports PIP -
 297                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 298     struct priority_distribution pdist; /* Priority summary of owned objects
 299                                   that have blocked threads and thread's own
 300                                   base priority */
 301     int skip_count;            /* Number of times skipped if higher priority
 302                                   thread was running */
 303     unsigned char base_priority; /* Base priority (set explicitly during
 304                                   creation or thread_set_priority) */
 305     unsigned char priority;    /* Scheduled priority (higher of base or
 306                                   all threads blocked by this one) */
 307 #endif
 308     uint16_t id;               /* Current slot id */
 309     unsigned short stack_size; /* Size of stack in bytes */
 310     unsigned char state;       /* Thread slot state (STATE_*) */
 311 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 312     unsigned char cpu_boost;   /* CPU frequency boost flag */
 313 #endif
 314 #ifdef HAVE_IO_PRIORITY
 315     unsigned char io_priority;
 316 #endif
 317 };
 318
 319 /*** Macros for internal use ***/
 320 /* Thread ID, 16 bits = |VVVVVVVV|SSSSSSSS| */
 321 #define THREAD_ID_VERSION_SHIFT      8
 322 #define THREAD_ID_VERSION_MASK  0xff00
 323 #define THREAD_ID_SLOT_MASK     0x00ff
 324 #define THREAD_ID_INIT(n)       ((1u << THREAD_ID_VERSION_SHIFT) | (n))
 325
 326 /* Specify current thread in a function taking an ID. */
 327 #define THREAD_ID_CURRENT ((unsigned int)-1)
 328
 329 #ifdef HAVE_CORELOCK_OBJECT
 330 /* Operations to be performed just before stopping a thread and starting
 331    a new one if specified before calling switch_thread */
 332 enum
 333 {
 334     TBOP_CLEAR = 0,       /* No operation to do */
 335     TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
 336     TBOP_SWITCH_CORE,     /* Call the core switch preparation routine */
 337 };
 338
 339 struct thread_blk_ops
 340 {
 341     struct corelock *cl_p;    /* pointer to corelock */
 342     unsigned char    flags;   /* TBOP_* flags */
 343 };
 344 #endif /* NUM_CORES > 1 */
 345
 346 /* Information kept for each core
 347  * Members are arranged for the same reason as in thread_entry
 348  */
 349 struct core_entry
 350 {
 351     /* "Active" lists - core is constantly active on these and are never
 352        locked and interrupts do not access them */
 353     struct thread_entry *running;  /* threads that are running (RTR) */
 354     struct thread_entry *timeout;  /* threads that are on a timeout before
 355                                       running again */
 356     struct thread_entry *block_task; /* Task going off running list */
 357 #ifdef HAVE_PRIORITY_SCHEDULING
 358     struct priority_distribution rtr; /* Summary of running and ready-to-run
 359                                          threads */
 360 #endif
 361     long next_tmo_check;           /* soonest time to check tmo threads */
 362 #ifdef HAVE_CORELOCK_OBJECT
 363     struct thread_blk_ops blk_ops; /* operations to perform when
 364                                       blocking a thread */
 365     struct corelock rtr_cl;        /* Lock for rtr list */
 366 #endif /* NUM_CORES */
 367 };
 368
 369 #ifdef HAVE_PRIORITY_SCHEDULING
 370 #define IF_PRIO(...)    __VA_ARGS__
 371 #define IFN_PRIO(...)
 372 #else
 373 #define IF_PRIO(...)
 374 #define IFN_PRIO(...)   __VA_ARGS__
 375 #endif
 376
 377 void core_idle(void);
 378 void core_wake(IF_COP_VOID(unsigned int core));
 379
 380 /* Initialize the scheduler */
 381 void init_threads(void) INIT_ATTR;
 382
 383 /* Allocate a thread in the scheduler */
 384 #define CREATE_THREAD_FROZEN   0x00000001 /* Thread is frozen at create time */
 385 unsigned int create_thread(void (*function)(void),
 386                            void* stack, size_t stack_size,
 387                            unsigned flags, const char *name
 388                            IF_PRIO(, int priority)
 389                            IF_COP(, unsigned int core));
 390
 391 /* Set and clear the CPU frequency boost flag for the calling thread */
 392 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 393 void trigger_cpu_boost(void);
 394 void cancel_cpu_boost(void);
 395 #else
 396 #define trigger_cpu_boost() do { } while(0)
 397 #define cancel_cpu_boost() do { } while(0)
 398 #endif
 399 /* Return thread entry from id */
 400 struct thread_entry *thread_id_entry(unsigned int thread_id);
 401 /* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
 402  * Has no effect on a thread not frozen. */
 403 void thread_thaw(unsigned int thread_id);
 404 /* Wait for a thread to exit */
 405 void thread_wait(unsigned int thread_id);
 406 /* Exit the current thread */
 407 void thread_exit(void) NORETURN_ATTR;
 408 #if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
 409 #define ALLOW_REMOVE_THREAD
 410 /* Remove a thread from the scheduler */
 411 void remove_thread(unsigned int thread_id);
 412 #endif
 413
 414 /* Switch to next runnable thread */
 415 void switch_thread(void);
 416 /* Blocks a thread for at least the specified number of ticks (0 = wait until
 417  * next tick) */
 418 void sleep_thread(int ticks);
 419 /* Indefinitely blocks the current thread on a thread queue */
 420 void block_thread(struct thread_entry *current);
 421 /* Blocks the current thread on a thread queue until explicitely woken or
 422  * the timeout is reached */
 423 void block_thread_w_tmo(struct thread_entry *current, int timeout);
 424
 425 /* Return bit flags for thread wakeup */
 426 #define THREAD_NONE     0x0 /* No thread woken up (exclusive) */
 427 #define THREAD_OK       0x1 /* A thread was woken up */
 428 #define THREAD_SWITCH   0x2 /* Task switch recommended (one or more of
 429                                higher priority than current were woken) */
 430
 431 /* A convenience function for waking an entire queue of threads. */
 432 unsigned int thread_queue_wake(struct thread_entry **list);
 433
 434 /* Wakeup a thread at the head of a list */
 435 unsigned int wakeup_thread(struct thread_entry **list);
 436
 437 #ifdef HAVE_PRIORITY_SCHEDULING
 438 int thread_set_priority(unsigned int thread_id, int priority);
 439 int thread_get_priority(unsigned int thread_id);
 440 #endif /* HAVE_PRIORITY_SCHEDULING */
 441 #ifdef HAVE_IO_PRIORITY
 442 void thread_set_io_priority(unsigned int thread_id, int io_priority);
 443 int thread_get_io_priority(unsigned int thread_id);
 444 #endif /* HAVE_IO_PRIORITY */
 445 #if NUM_CORES > 1
 446 unsigned int switch_core(unsigned int new_core);
 447 #endif
 448 unsigned int thread_get_current(void);
 449
 450 /* Debugging info - only! */
 451 int thread_stack_usage(const struct thread_entry *thread);
 452 #if NUM_CORES > 1
 453 int idle_stack_usage(unsigned int core);
 454 #endif
 455 void thread_get_name(char *buffer, int size,
 456                      struct thread_entry *thread);
 457 #ifdef RB_PROFILE
 458 void profile_thread(void);
 459 #endif
 460
 461 #endif /* THREAD_H */