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