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 #if CONFIG_CODEC == SWCODEC
  62
  63 #ifdef HAVE_RECORDING
  64 #define BASETHREADS  17
  65 #else
  66 #define BASETHREADS  16
  67 #endif
  68
  69 #else
  70 #define BASETHREADS  11
  71 #endif /* CONFIG_CODE == * */
  72
  73 #ifndef TARGET_EXTRA_THREADS
  74 #define TARGET_EXTRA_THREADS 0
  75 #endif
  76
  77 #define MAXTHREADS (BASETHREADS+TARGET_EXTRA_THREADS)
  78
  79 #define DEFAULT_STACK_SIZE 0x400 /* Bytes */
  80
  81 #ifndef SIMULATOR
  82 /* Need to keep structures inside the header file because debug_menu
  83  * needs them. */
  84 #ifdef CPU_COLDFIRE
  85 struct regs
  86 {
  87     uint32_t macsr; /*     0 - EMAC status register */
  88     uint32_t d[6];  /*  4-24 - d2-d7 */
  89     uint32_t a[5];  /* 28-44 - a2-a6 */
  90     uint32_t sp;    /*    48 - Stack pointer (a7) */
  91     uint32_t start; /*    52 - Thread start address, or NULL when started */
  92 };
  93 #elif CONFIG_CPU == SH7034
  94 struct regs
  95 {
  96     uint32_t r[7];  /*  0-24 - Registers r8 thru r14 */
  97     uint32_t sp;    /*    28 - Stack pointer (r15) */
  98     uint32_t pr;    /*    32 - Procedure register */
  99     uint32_t start; /*    36 - Thread start address, or NULL when started */
 100 };
 101 #elif defined(CPU_ARM)
 102 struct regs
 103 {
 104     uint32_t r[8];  /*  0-28 - Registers r4-r11 */
 105     uint32_t sp;    /*    32 - Stack pointer (r13) */
 106     uint32_t lr;    /*    36 - r14 (lr) */
 107     uint32_t start; /*    40 - Thread start address, or NULL when started */
 108 };
 109 #elif defined(CPU_MIPS)
 110 struct regs
 111 {
 112     uint32_t r[9];  /* 0-32 - Registers s0-s7, fp */
 113     uint32_t sp;    /*   36 - Stack pointer */
 114     uint32_t ra;    /*   40 - Return address */
 115     uint32_t start; /*   44 - Thread start address, or NULL when started */
 116 };
 117 #endif /* CONFIG_CPU */
 118 #else
 119 struct regs
 120 {
 121     void *t;             /* Simulator OS thread */
 122     void *s;             /* Semaphore for blocking and wakeup */
 123     void (*start)(void); /* Start function */
 124 };
 125 #endif /* !SIMULATOR */
 126
 127 /* NOTE: The use of the word "queue" may also refer to a linked list of
 128    threads being maintained that are normally dealt with in FIFO order
 129    and not necessarily kernel event_queue */
 130 enum
 131 {
 132     /* States without a timeout must be first */
 133     STATE_KILLED = 0,    /* Thread is killed (default) */
 134     STATE_RUNNING,       /* Thread is currently running */
 135     STATE_BLOCKED,       /* Thread is indefinitely blocked on a queue */
 136     /* These states involve adding the thread to the tmo list */
 137     STATE_SLEEPING,      /* Thread is sleeping with a timeout */
 138     STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
 139     /* Miscellaneous states */
 140     STATE_FROZEN,        /* Thread is suspended and will not run until
 141                             thread_thaw is called with its ID */
 142     THREAD_NUM_STATES,
 143     TIMEOUT_STATE_FIRST = STATE_SLEEPING,
 144 };
 145
 146 #if NUM_CORES > 1
 147 /* Pointer value for name field to indicate thread is being killed. Using
 148  * an alternate STATE_* won't work since that would interfere with operation
 149  * while the thread is still running. */
 150 #define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
 151 #endif
 152
 153 /* Link information for lists thread is in */
 154 struct thread_entry; /* forward */
 155 struct thread_list
 156 {
 157     struct thread_entry *prev; /* Previous thread in a list */
 158     struct thread_entry *next; /* Next thread in a list */
 159 };
 160
 161 /* Small objects for core-wise mutual exclusion */
 162 #if CONFIG_CORELOCK == SW_CORELOCK
 163 /* No reliable atomic instruction available - use Peterson's algorithm */
 164 struct corelock
 165 {
 166     volatile unsigned char myl[NUM_CORES];
 167     volatile unsigned char turn;
 168 } __attribute__((packed));
 169
 170 void corelock_init(struct corelock *cl);
 171 void corelock_lock(struct corelock *cl);
 172 int corelock_try_lock(struct corelock *cl);
 173 void corelock_unlock(struct corelock *cl);
 174 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 175 /* Use native atomic swap/exchange instruction */
 176 struct corelock
 177 {
 178     volatile unsigned char locked;
 179 } __attribute__((packed));
 180
 181 #define corelock_init(cl) \
 182     ({ (cl)->locked = 0; })
 183 #define corelock_lock(cl) \
 184     ({ while (test_and_set(&(cl)->locked, 1)); })
 185 #define corelock_try_lock(cl) \
 186     ({ test_and_set(&(cl)->locked, 1) ? 0 : 1; })
 187 #define corelock_unlock(cl) \
 188     ({ (cl)->locked = 0; })
 189 #else
 190 /* No atomic corelock op needed or just none defined */
 191 #define corelock_init(cl)
 192 #define corelock_lock(cl)
 193 #define corelock_try_lock(cl)
 194 #define corelock_unlock(cl)
 195 #endif /* core locking selection */
 196
 197 #ifdef HAVE_PRIORITY_SCHEDULING
 198 struct blocker
 199 {
 200     struct thread_entry *thread;   /* thread blocking other threads
 201                                       (aka. object owner) */
 202     int priority;                  /* highest priority waiter */
 203     struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
 204 };
 205
 206 /* Choices of wakeup protocol */
 207
 208 /* For transfer of object ownership by one thread to another thread by
 209  * the owning thread itself (mutexes) */
 210 struct thread_entry *
 211     wakeup_priority_protocol_transfer(struct thread_entry *thread);
 212
 213 /* For release by owner where ownership doesn't change - other threads,
 214  * interrupts, timeouts, etc. (mutex timeout, queues) */
 215 struct thread_entry *
 216     wakeup_priority_protocol_release(struct thread_entry *thread);
 217
 218
 219 struct priority_distribution
 220 {
 221     uint8_t  hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
 222     uint32_t mask;                 /* Bitmask of hist entries that are not zero */
 223 };
 224
 225 #endif /* HAVE_PRIORITY_SCHEDULING */
 226
 227 /* Information kept in each thread slot
 228  * members are arranged according to size - largest first - in order
 229  * to ensure both alignment and packing at the same time.
 230  */
 231 struct thread_entry
 232 {
 233     struct regs context;       /* Register context at switch -
 234                                   _must_ be first member */
 235     uintptr_t *stack;          /* Pointer to top of stack */
 236     const char *name;          /* Thread name */
 237     long tmo_tick;             /* Tick when thread should be woken from
 238                                   timeout -
 239                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 240     struct thread_list l;      /* Links for blocked/waking/running -
 241                                   circular linkage in both directions */
 242     struct thread_list tmo;    /* Links for timeout list -
 243                                   Circular in reverse direction, NULL-terminated in
 244                                   forward direction -
 245                                   states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
 246     struct thread_entry **bqp; /* Pointer to list variable in kernel
 247                                   object where thread is blocked - used
 248                                   for implicit unblock and explicit wake
 249                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 250 #if NUM_CORES > 1
 251     struct corelock *obj_cl;   /* Object corelock where thead is blocked -
 252                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
 253 #endif
 254     struct thread_entry *queue; /* List of threads waiting for thread to be
 255                                   removed */
 256 #ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
 257     #define HAVE_WAKEUP_EXT_CB
 258     void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
 259                                   performs special steps needed when being
 260                                   forced off of an object's wait queue that
 261                                   go beyond the standard wait queue removal
 262                                   and priority disinheritance */
 263     /* Only enabled when using queue_send for now */
 264 #endif
 265 #if defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || NUM_CORES > 1
 266     intptr_t retval;           /* Return value from a blocked operation/
 267                                   misc. use */
 268 #endif
 269 #ifdef HAVE_PRIORITY_SCHEDULING
 270     /* Priority summary of owned objects that support inheritance */
 271     struct blocker *blocker;   /* Pointer to blocker when this thread is blocked
 272                                   on an object that supports PIP -
 273                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 274     struct priority_distribution pdist; /* Priority summary of owned objects
 275                                   that have blocked threads and thread's own
 276                                   base priority */
 277     int skip_count;            /* Number of times skipped if higher priority
 278                                   thread was running */
 279 #endif
 280     uint16_t id;               /* Current slot id */
 281     unsigned short stack_size; /* Size of stack in bytes */
 282 #ifdef HAVE_PRIORITY_SCHEDULING
 283     unsigned char base_priority; /* Base priority (set explicitly during
 284                                   creation or thread_set_priority) */
 285     unsigned char priority;    /* Scheduled priority (higher of base or
 286                                   all threads blocked by this one) */
 287 #endif
 288     unsigned char state;       /* Thread slot state (STATE_*) */
 289 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 290     unsigned char cpu_boost;   /* CPU frequency boost flag */
 291 #endif
 292 #if NUM_CORES > 1
 293     unsigned char core;        /* The core to which thread belongs */
 294     struct corelock waiter_cl; /* Corelock for thread_wait */
 295     struct corelock slot_cl;   /* Corelock to lock thread slot */
 296 #endif
 297 };
 298
 299 /*** Macros for internal use ***/
 300 /* Thread ID, 16 bits = |VVVVVVVV|SSSSSSSS| */
 301 #define THREAD_ID_VERSION_SHIFT      8
 302 #define THREAD_ID_VERSION_MASK  0xff00
 303 #define THREAD_ID_SLOT_MASK     0x00ff
 304 #define THREAD_ID_INIT(n)       ((1u << THREAD_ID_VERSION_SHIFT) | (n))
 305
 306 /* Specify current thread in a function taking an ID. */
 307 #define THREAD_ID_CURRENT ((unsigned int)-1)
 308
 309 #if NUM_CORES > 1
 310 /* Operations to be performed just before stopping a thread and starting
 311    a new one if specified before calling switch_thread */
 312 enum
 313 {
 314     TBOP_CLEAR = 0,       /* No operation to do */
 315     TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
 316     TBOP_SWITCH_CORE,     /* Call the core switch preparation routine */
 317 };
 318
 319 struct thread_blk_ops
 320 {
 321     struct corelock *cl_p;    /* pointer to corelock */
 322     unsigned char    flags;   /* TBOP_* flags */
 323 };
 324 #endif /* NUM_CORES > 1 */
 325
 326 /* Information kept for each core
 327  * Members are arranged for the same reason as in thread_entry
 328  */
 329 struct core_entry
 330 {
 331     /* "Active" lists - core is constantly active on these and are never
 332        locked and interrupts do not access them */
 333     struct thread_entry *running;  /* threads that are running (RTR) */
 334     struct thread_entry *timeout;  /* threads that are on a timeout before
 335                                       running again */
 336     struct thread_entry *block_task; /* Task going off running list */
 337 #ifdef HAVE_PRIORITY_SCHEDULING
 338     struct priority_distribution rtr; /* Summary of running and ready-to-run
 339                                          threads */
 340 #endif
 341     long next_tmo_check;           /* soonest time to check tmo threads */
 342 #if NUM_CORES > 1
 343     struct thread_blk_ops blk_ops; /* operations to perform when
 344                                       blocking a thread */
 345     struct corelock rtr_cl;        /* Lock for rtr list */
 346 #endif /* NUM_CORES */
 347 };
 348
 349 #ifdef HAVE_PRIORITY_SCHEDULING
 350 #define IF_PRIO(...)    __VA_ARGS__
 351 #define IFN_PRIO(...)
 352 #else
 353 #define IF_PRIO(...)
 354 #define IFN_PRIO(...)   __VA_ARGS__
 355 #endif
 356
 357 /* Macros generate better code than an inline function is this case */
 358 #if (defined (CPU_PP) || defined (CPU_ARM))
 359 /* atomic */
 360 #if CONFIG_CORELOCK == SW_CORELOCK
 361 #define test_and_set(a, v, cl) \
 362     xchg8((a), (v), (cl))
 363 /* atomic */
 364 #define xchg8(a, v, cl) \
 365 ({  uint32_t o;            \
 366     corelock_lock(cl);     \
 367     o = *(uint8_t *)(a);   \
 368     *(uint8_t *)(a) = (v); \
 369     corelock_unlock(cl);   \
 370     o; })
 371 #define xchg32(a, v, cl) \
 372 ({  uint32_t o;             \
 373     corelock_lock(cl);      \
 374     o = *(uint32_t *)(a);   \
 375     *(uint32_t *)(a) = (v); \
 376     corelock_unlock(cl);    \
 377     o; })
 378 #define xchgptr(a, v, cl) \
 379 ({  typeof (*(a)) o;     \
 380     corelock_lock(cl);   \
 381     o = *(a);            \
 382     *(a) = (v);          \
 383     corelock_unlock(cl); \
 384     o; })
 385 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 386 /* atomic */
 387 #define test_and_set(a, v, ...) \
 388     xchg8((a), (v))
 389 #define xchg8(a, v, ...) \
 390 ({  uint32_t o;                \
 391     asm volatile(              \
 392         "swpb %0, %1, [%2]"    \
 393         : "=&r"(o)             \
 394         : "r"(v),              \
 395           "r"((uint8_t*)(a))); \
 396     o; })
 397 /* atomic */
 398 #define xchg32(a, v, ...) \
 399 ({  uint32_t o;                 \
 400     asm volatile(               \
 401         "swp %0, %1, [%2]"      \
 402         : "=&r"(o)              \
 403         : "r"((uint32_t)(v)),   \
 404           "r"((uint32_t*)(a))); \
 405     o; })
 406 /* atomic */
 407 #define xchgptr(a, v, ...) \
 408 ({  typeof (*(a)) o;        \
 409     asm volatile(           \
 410         "swp %0, %1, [%2]"  \
 411         : "=&r"(o)          \
 412         : "r"(v), "r"(a));  \
 413     o; })
 414 #endif /* locking selection */
 415 #elif defined (CPU_COLDFIRE)
 416 /* atomic */
 417 /* one branch will be optimized away if v is a constant expression */
 418 #define test_and_set(a, v, ...) \
 419 ({  uint32_t o = 0;                \
 420     if (v) {                       \
 421         asm volatile (             \
 422             "bset.b #0, (%0)"      \
 423             : : "a"((uint8_t*)(a)) \
 424             : "cc");               \
 425     } else {                       \
 426         asm volatile (             \
 427             "bclr.b #0, (%0)"      \
 428             : : "a"((uint8_t*)(a)) \
 429             : "cc");               \
 430     }                              \
 431     asm volatile ("sne.b %0"       \
 432         : "+d"(o));                \
 433     o; })
 434 #elif CONFIG_CPU == SH7034
 435 /* atomic */
 436 #define test_and_set(a, v, ...) \
 437 ({  uint32_t o;                 \
 438     asm volatile (              \
 439         "tas.b  @%2     \n"     \
 440         "mov    #-1, %0 \n"     \
 441         "negc   %0, %0  \n"     \
 442         : "=r"(o)               \
 443         : "M"((uint32_t)(v)),   /* Value of_v must be 1 */ \
 444           "r"((uint8_t *)(a))); \
 445     o; })
 446 #endif /* CONFIG_CPU == */
 447
 448 /* defaults for no asm version */
 449 #ifndef test_and_set
 450 /* not atomic */
 451 #define test_and_set(a, v, ...) \
 452 ({  uint32_t o = *(uint8_t *)(a); \
 453     *(uint8_t *)(a) = (v);        \
 454     o; })
 455 #endif /* test_and_set */
 456 #ifndef xchg8
 457 /* not atomic */
 458 #define xchg8(a, v, ...) \
 459 ({  uint32_t o = *(uint8_t *)(a); \
 460     *(uint8_t *)(a) = (v);        \
 461     o; })
 462 #endif /* xchg8 */
 463 #ifndef xchg32
 464 /* not atomic */
 465 #define xchg32(a, v, ...) \
 466 ({  uint32_t o = *(uint32_t *)(a); \
 467     *(uint32_t *)(a) = (v);        \
 468     o; })
 469 #endif /* xchg32 */
 470 #ifndef xchgptr
 471 /* not atomic */
 472 #define xchgptr(a, v, ...) \
 473 ({  typeof (*(a)) o = *(a); \
 474     *(a) = (v);             \
 475     o; })
 476 #endif /* xchgptr */
 477
 478 void core_idle(void);
 479 void core_wake(IF_COP_VOID(unsigned int core));
 480
 481 /* Initialize the scheduler */
 482 void init_threads(void) INIT_ATTR;
 483
 484 /* Allocate a thread in the scheduler */
 485 #define CREATE_THREAD_FROZEN   0x00000001 /* Thread is frozen at create time */
 486 unsigned int create_thread(void (*function)(void),
 487                            void* stack, size_t stack_size,
 488                            unsigned flags, const char *name
 489                            IF_PRIO(, int priority)
 490                            IF_COP(, unsigned int core));
 491
 492 /* Set and clear the CPU frequency boost flag for the calling thread */
 493 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 494 void trigger_cpu_boost(void);
 495 void cancel_cpu_boost(void);
 496 #else
 497 #define trigger_cpu_boost()
 498 #define cancel_cpu_boost()
 499 #endif
 500 /* Return thread entry from id */
 501 struct thread_entry *thread_id_entry(unsigned int thread_id);
 502 /* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
 503  * Has no effect on a thread not frozen. */
 504 void thread_thaw(unsigned int thread_id);
 505 /* Wait for a thread to exit */
 506 void thread_wait(unsigned int thread_id);
 507 /* Exit the current thread */
 508 void thread_exit(void);
 509 #if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
 510 #define ALLOW_REMOVE_THREAD
 511 /* Remove a thread from the scheduler */
 512 void remove_thread(unsigned int thread_id);
 513 #endif
 514
 515 /* Switch to next runnable thread */
 516 void switch_thread(void);
 517 /* Blocks a thread for at least the specified number of ticks (0 = wait until
 518  * next tick) */
 519 void sleep_thread(int ticks);
 520 /* Indefinitely blocks the current thread on a thread queue */
 521 void block_thread(struct thread_entry *current);
 522 /* Blocks the current thread on a thread queue until explicitely woken or
 523  * the timeout is reached */
 524 void block_thread_w_tmo(struct thread_entry *current, int timeout);
 525
 526 /* Return bit flags for thread wakeup */
 527 #define THREAD_NONE     0x0 /* No thread woken up (exclusive) */
 528 #define THREAD_OK       0x1 /* A thread was woken up */
 529 #define THREAD_SWITCH   0x2 /* Task switch recommended (one or more of
 530                                higher priority than current were woken) */
 531
 532 /* A convenience function for waking an entire queue of threads. */
 533 unsigned int thread_queue_wake(struct thread_entry **list);
 534
 535 /* Wakeup a thread at the head of a list */
 536 unsigned int wakeup_thread(struct thread_entry **list);
 537
 538 #ifdef HAVE_PRIORITY_SCHEDULING
 539 int thread_set_priority(unsigned int thread_id, int priority);
 540 int thread_get_priority(unsigned int thread_id);
 541 #endif /* HAVE_PRIORITY_SCHEDULING */
 542 #if NUM_CORES > 1
 543 unsigned int switch_core(unsigned int new_core);
 544 #endif
 545 unsigned int thread_get_current(void);
 546
 547 /* Debugging info - only! */
 548 int thread_stack_usage(const struct thread_entry *thread);
 549 #if NUM_CORES > 1
 550 int idle_stack_usage(unsigned int core);
 551 #endif
 552 void thread_get_name(char *buffer, int size,
 553                      struct thread_entry *thread);
 554 #ifdef RB_PROFILE
 555 void profile_thread(void);
 556 #endif
 557
 558 #endif /* THREAD_H */