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