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 #elif defined(CPU_MIPS)
 113 struct regs
 114 {
 115     uint32_t r[9];  /* 0-32 - Registers s0-s7, fp */
 116     uint32_t sp;    /*   36 - Stack pointer */
 117     uint32_t ra;    /*   40 - Return address */
 118     uint32_t start; /*   44 - Thread start address, or NULL when started */
 119 };
 120 #endif /* CONFIG_CPU */
 121 #elif (CONFIG_PLATFORM & PLATFORM_HOSTED)
 122 struct regs
 123 {
 124     void *t;             /* OS thread */
 125     void *told;          /* Last thread in slot (explained in thead-sdl.c) */
 126     void *s;             /* Semaphore for blocking and wakeup */
 127     void (*start)(void); /* Start function */
 128 };
 129 #endif /* PLATFORM_NATIVE */
 130
 131 /* NOTE: The use of the word "queue" may also refer to a linked list of
 132    threads being maintained that are normally dealt with in FIFO order
 133    and not necessarily kernel event_queue */
 134 enum
 135 {
 136     /* States without a timeout must be first */
 137     STATE_KILLED = 0,    /* Thread is killed (default) */
 138     STATE_RUNNING,       /* Thread is currently running */
 139     STATE_BLOCKED,       /* Thread is indefinitely blocked on a queue */
 140     /* These states involve adding the thread to the tmo list */
 141     STATE_SLEEPING,      /* Thread is sleeping with a timeout */
 142     STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
 143     /* Miscellaneous states */
 144     STATE_FROZEN,        /* Thread is suspended and will not run until
 145                             thread_thaw is called with its ID */
 146     THREAD_NUM_STATES,
 147     TIMEOUT_STATE_FIRST = STATE_SLEEPING,
 148 };
 149
 150 #if NUM_CORES > 1
 151 /* Pointer value for name field to indicate thread is being killed. Using
 152  * an alternate STATE_* won't work since that would interfere with operation
 153  * while the thread is still running. */
 154 #define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
 155 #endif
 156
 157 /* Link information for lists thread is in */
 158 struct thread_entry; /* forward */
 159 struct thread_list
 160 {
 161     struct thread_entry *prev; /* Previous thread in a list */
 162     struct thread_entry *next; /* Next thread in a list */
 163 };
 164
 165 /* Small objects for core-wise mutual exclusion */
 166 #if CONFIG_CORELOCK == SW_CORELOCK
 167 /* No reliable atomic instruction available - use Peterson's algorithm */
 168 struct corelock
 169 {
 170     volatile unsigned char myl[NUM_CORES];
 171     volatile unsigned char turn;
 172 } __attribute__((packed));
 173
 174 void corelock_init(struct corelock *cl);
 175 void corelock_lock(struct corelock *cl);
 176 int corelock_try_lock(struct corelock *cl);
 177 void corelock_unlock(struct corelock *cl);
 178 #else
 179 /* No atomic corelock op needed or just none defined */
 180 #define corelock_init(cl)
 181 #define corelock_lock(cl)
 182 #define corelock_try_lock(cl)
 183 #define corelock_unlock(cl)
 184 #endif /* core locking selection */
 185
 186 #ifdef HAVE_PRIORITY_SCHEDULING
 187 struct blocker
 188 {
 189     struct thread_entry *thread;   /* thread blocking other threads
 190                                       (aka. object owner) */
 191     int priority;                  /* highest priority waiter */
 192     struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
 193 };
 194
 195 /* Choices of wakeup protocol */
 196
 197 /* For transfer of object ownership by one thread to another thread by
 198  * the owning thread itself (mutexes) */
 199 struct thread_entry *
 200     wakeup_priority_protocol_transfer(struct thread_entry *thread);
 201
 202 /* For release by owner where ownership doesn't change - other threads,
 203  * interrupts, timeouts, etc. (mutex timeout, queues) */
 204 struct thread_entry *
 205     wakeup_priority_protocol_release(struct thread_entry *thread);
 206
 207
 208 struct priority_distribution
 209 {
 210     uint8_t  hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
 211     uint32_t mask;                 /* Bitmask of hist entries that are not zero */
 212 };
 213
 214 #endif /* HAVE_PRIORITY_SCHEDULING */
 215
 216 /* Information kept in each thread slot
 217  * members are arranged according to size - largest first - in order
 218  * to ensure both alignment and packing at the same time.
 219  */
 220 struct thread_entry
 221 {
 222     struct regs context;       /* Register context at switch -
 223                                   _must_ be first member */
 224     uintptr_t *stack;          /* Pointer to top of stack */
 225     const char *name;          /* Thread name */
 226     long tmo_tick;             /* Tick when thread should be woken from
 227                                   timeout -
 228                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 229     struct thread_list l;      /* Links for blocked/waking/running -
 230                                   circular linkage in both directions */
 231     struct thread_list tmo;    /* Links for timeout list -
 232                                   Circular in reverse direction, NULL-terminated in
 233                                   forward direction -
 234                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 235     struct thread_entry **bqp; /* Pointer to list variable in kernel
 236                                   object where thread is blocked - used
 237                                   for implicit unblock and explicit wake
 238                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 239 #if NUM_CORES > 1
 240     struct corelock *obj_cl;   /* Object corelock where thead is blocked -
 241                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
 242     struct corelock waiter_cl; /* Corelock for thread_wait */
 243     struct corelock slot_cl;   /* Corelock to lock thread slot */
 244     unsigned char core;        /* The core to which thread belongs */
 245 #endif
 246     struct thread_entry *queue; /* List of threads waiting for thread to be
 247                                   removed */
 248 #ifdef HAVE_WAKEUP_EXT_CB
 249     void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
 250                                   performs special steps needed when being
 251                                   forced off of an object's wait queue that
 252                                   go beyond the standard wait queue removal
 253                                   and priority disinheritance */
 254     /* Only enabled when using queue_send for now */
 255 #endif
 256 #if defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || NUM_CORES > 1
 257     intptr_t retval;           /* Return value from a blocked operation/
 258                                   misc. use */
 259 #endif
 260 #ifdef HAVE_PRIORITY_SCHEDULING
 261     /* Priority summary of owned objects that support inheritance */
 262     struct blocker *blocker;   /* Pointer to blocker when this thread is blocked
 263                                   on an object that supports PIP -
 264                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 265     struct priority_distribution pdist; /* Priority summary of owned objects
 266                                   that have blocked threads and thread's own
 267                                   base priority */
 268     int skip_count;            /* Number of times skipped if higher priority
 269                                   thread was running */
 270     unsigned char base_priority; /* Base priority (set explicitly during
 271                                   creation or thread_set_priority) */
 272     unsigned char priority;    /* Scheduled priority (higher of base or
 273                                   all threads blocked by this one) */
 274 #endif
 275     uint16_t id;               /* Current slot id */
 276     unsigned short stack_size; /* Size of stack in bytes */
 277     unsigned char state;       /* Thread slot state (STATE_*) */
 278 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 279     unsigned char cpu_boost;   /* CPU frequency boost flag */
 280 #endif
 281 #ifdef HAVE_IO_PRIORITY
 282     unsigned char io_priority;
 283 #endif
 284 };
 285
 286 /*** Macros for internal use ***/
 287 /* Thread ID, 16 bits = |VVVVVVVV|SSSSSSSS| */
 288 #define THREAD_ID_VERSION_SHIFT      8
 289 #define THREAD_ID_VERSION_MASK  0xff00
 290 #define THREAD_ID_SLOT_MASK     0x00ff
 291 #define THREAD_ID_INIT(n)       ((1u << THREAD_ID_VERSION_SHIFT) | (n))
 292
 293 /* Specify current thread in a function taking an ID. */
 294 #define THREAD_ID_CURRENT ((unsigned int)-1)
 295
 296 #if NUM_CORES > 1
 297 /* Operations to be performed just before stopping a thread and starting
 298    a new one if specified before calling switch_thread */
 299 enum
 300 {
 301     TBOP_CLEAR = 0,       /* No operation to do */
 302     TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
 303     TBOP_SWITCH_CORE,     /* Call the core switch preparation routine */
 304 };
 305
 306 struct thread_blk_ops
 307 {
 308     struct corelock *cl_p;    /* pointer to corelock */
 309     unsigned char    flags;   /* TBOP_* flags */
 310 };
 311 #endif /* NUM_CORES > 1 */
 312
 313 /* Information kept for each core
 314  * Members are arranged for the same reason as in thread_entry
 315  */
 316 struct core_entry
 317 {
 318     /* "Active" lists - core is constantly active on these and are never
 319        locked and interrupts do not access them */
 320     struct thread_entry *running;  /* threads that are running (RTR) */
 321     struct thread_entry *timeout;  /* threads that are on a timeout before
 322                                       running again */
 323     struct thread_entry *block_task; /* Task going off running list */
 324 #ifdef HAVE_PRIORITY_SCHEDULING
 325     struct priority_distribution rtr; /* Summary of running and ready-to-run
 326                                          threads */
 327 #endif
 328     long next_tmo_check;           /* soonest time to check tmo threads */
 329 #if NUM_CORES > 1
 330     struct thread_blk_ops blk_ops; /* operations to perform when
 331                                       blocking a thread */
 332     struct corelock rtr_cl;        /* Lock for rtr list */
 333 #endif /* NUM_CORES */
 334 };
 335
 336 #ifdef HAVE_PRIORITY_SCHEDULING
 337 #define IF_PRIO(...)    __VA_ARGS__
 338 #define IFN_PRIO(...)
 339 #else
 340 #define IF_PRIO(...)
 341 #define IFN_PRIO(...)   __VA_ARGS__
 342 #endif
 343
 344 /* Macros generate better code than an inline function is this case */
 345 #if defined (CPU_ARM)
 346 /* atomic */
 347 #if CONFIG_CORELOCK == SW_CORELOCK
 348 #define test_and_set(a, v, cl) \
 349     xchg8((a), (v), (cl))
 350 /* atomic */
 351 #define xchg8(a, v, cl) \
 352 ({  uint32_t o;            \
 353     corelock_lock(cl);     \
 354     o = *(uint8_t *)(a);   \
 355     *(uint8_t *)(a) = (v); \
 356     corelock_unlock(cl);   \
 357     o; })
 358 #define xchg32(a, v, cl) \
 359 ({  uint32_t o;             \
 360     corelock_lock(cl);      \
 361     o = *(uint32_t *)(a);   \
 362     *(uint32_t *)(a) = (v); \
 363     corelock_unlock(cl);    \
 364     o; })
 365 #define xchgptr(a, v, cl) \
 366 ({  typeof (*(a)) o;     \
 367     corelock_lock(cl);   \
 368     o = *(a);            \
 369     *(a) = (v);          \
 370     corelock_unlock(cl); \
 371     o; })
 372 #endif /* locking selection */
 373 #elif defined (CPU_COLDFIRE)
 374 /* atomic */
 375 /* one branch will be optimized away if v is a constant expression */
 376 #define test_and_set(a, v, ...) \
 377 ({  uint32_t o = 0;                \
 378     if (v) {                       \
 379         asm volatile (             \
 380             "bset.b #0, (%0)"      \
 381             : : "a"((uint8_t*)(a)) \
 382             : "cc");               \
 383     } else {                       \
 384         asm volatile (             \
 385             "bclr.b #0, (%0)"      \
 386             : : "a"((uint8_t*)(a)) \
 387             : "cc");               \
 388     }                              \
 389     asm volatile ("sne.b %0"       \
 390         : "+d"(o));                \
 391     o; })
 392 #elif CONFIG_CPU == SH7034
 393 /* atomic */
 394 #define test_and_set(a, v, ...) \
 395 ({  uint32_t o;                 \
 396     asm volatile (              \
 397         "tas.b  @%2     \n"     \
 398         "mov    #-1, %0 \n"     \
 399         "negc   %0, %0  \n"     \
 400         : "=r"(o)               \
 401         : "M"((uint32_t)(v)),   /* Value of_v must be 1 */ \
 402           "r"((uint8_t *)(a))); \
 403     o; })
 404 #endif /* CONFIG_CPU == */
 405
 406 /* defaults for no asm version */
 407 #ifndef test_and_set
 408 /* not atomic */
 409 #define test_and_set(a, v, ...) \
 410 ({  uint32_t o = *(uint8_t *)(a); \
 411     *(uint8_t *)(a) = (v);        \
 412     o; })
 413 #endif /* test_and_set */
 414 #ifndef xchg8
 415 /* not atomic */
 416 #define xchg8(a, v, ...) \
 417 ({  uint32_t o = *(uint8_t *)(a); \
 418     *(uint8_t *)(a) = (v);        \
 419     o; })
 420 #endif /* xchg8 */
 421 #ifndef xchg32
 422 /* not atomic */
 423 #define xchg32(a, v, ...) \
 424 ({  uint32_t o = *(uint32_t *)(a); \
 425     *(uint32_t *)(a) = (v);        \
 426     o; })
 427 #endif /* xchg32 */
 428 #ifndef xchgptr
 429 /* not atomic */
 430 #define xchgptr(a, v, ...) \
 431 ({  typeof (*(a)) o = *(a); \
 432     *(a) = (v);             \
 433     o; })
 434 #endif /* xchgptr */
 435
 436 void core_idle(void);
 437 void core_wake(IF_COP_VOID(unsigned int core));
 438
 439 /* Initialize the scheduler */
 440 void init_threads(void) INIT_ATTR;
 441
 442 /* Allocate a thread in the scheduler */
 443 #define CREATE_THREAD_FROZEN   0x00000001 /* Thread is frozen at create time */
 444 unsigned int create_thread(void (*function)(void),
 445                            void* stack, size_t stack_size,
 446                            unsigned flags, const char *name
 447                            IF_PRIO(, int priority)
 448                            IF_COP(, unsigned int core));
 449
 450 /* Set and clear the CPU frequency boost flag for the calling thread */
 451 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 452 void trigger_cpu_boost(void);
 453 void cancel_cpu_boost(void);
 454 #else
 455 #define trigger_cpu_boost()
 456 #define cancel_cpu_boost()
 457 #endif
 458 /* Return thread entry from id */
 459 struct thread_entry *thread_id_entry(unsigned int thread_id);
 460 /* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
 461  * Has no effect on a thread not frozen. */
 462 void thread_thaw(unsigned int thread_id);
 463 /* Wait for a thread to exit */
 464 void thread_wait(unsigned int thread_id);
 465 /* Exit the current thread */
 466 void thread_exit(void);
 467 #if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
 468 #define ALLOW_REMOVE_THREAD
 469 /* Remove a thread from the scheduler */
 470 void remove_thread(unsigned int thread_id);
 471 #endif
 472
 473 /* Switch to next runnable thread */
 474 void switch_thread(void);
 475 /* Blocks a thread for at least the specified number of ticks (0 = wait until
 476  * next tick) */
 477 void sleep_thread(int ticks);
 478 /* Indefinitely blocks the current thread on a thread queue */
 479 void block_thread(struct thread_entry *current);
 480 /* Blocks the current thread on a thread queue until explicitely woken or
 481  * the timeout is reached */
 482 void block_thread_w_tmo(struct thread_entry *current, int timeout);
 483
 484 /* Return bit flags for thread wakeup */
 485 #define THREAD_NONE     0x0 /* No thread woken up (exclusive) */
 486 #define THREAD_OK       0x1 /* A thread was woken up */
 487 #define THREAD_SWITCH   0x2 /* Task switch recommended (one or more of
 488                                higher priority than current were woken) */
 489
 490 /* A convenience function for waking an entire queue of threads. */
 491 unsigned int thread_queue_wake(struct thread_entry **list);
 492
 493 /* Wakeup a thread at the head of a list */
 494 unsigned int wakeup_thread(struct thread_entry **list);
 495
 496 #ifdef HAVE_PRIORITY_SCHEDULING
 497 int thread_set_priority(unsigned int thread_id, int priority);
 498 int thread_get_priority(unsigned int thread_id);
 499 #endif /* HAVE_PRIORITY_SCHEDULING */
 500 #ifdef HAVE_IO_PRIORITY
 501 void thread_set_io_priority(unsigned int thread_id, int io_priority);
 502 int thread_get_io_priority(unsigned int thread_id);
 503 #endif /* HAVE_IO_PRIORITY */
 504 #if NUM_CORES > 1
 505 unsigned int switch_core(unsigned int new_core);
 506 #endif
 507 unsigned int thread_get_current(void);
 508
 509 /* Debugging info - only! */
 510 int thread_stack_usage(const struct thread_entry *thread);
 511 #if NUM_CORES > 1
 512 int idle_stack_usage(unsigned int core);
 513 #endif
 514 void thread_get_name(char *buffer, int size,
 515                      struct thread_entry *thread);
 516 #ifdef RB_PROFILE
 517 void profile_thread(void);
 518 #endif
 519
 520 #endif /* THREAD_H */