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