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 /* TODO: Only a minor tweak to create_thread would be needed to let
  62  * thread slots be caller allocated - no essential threading functionality
  63  * depends upon an array */
  64 #if CONFIG_CODEC == SWCODEC
  65
  66 #ifdef HAVE_RECORDING
  67 #define BASETHREADS  18
  68 #else
  69 #define BASETHREADS  17
  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 #ifndef SIMULATOR
  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[10]; /* 0-36 - Registers s0-s7, gp, fp */
 116     uint32_t sp;    /*   40 - Stack pointer */
 117     uint32_t ra;    /*   44 - Return address */
 118     uint32_t start; /*   48 - Thread start address, or NULL when started */
 119 };
 120 #endif /* CONFIG_CPU */
 121 #else
 122 struct regs
 123 {
 124     void *t;             /* Simulator OS thread */
 125     void *s;             /* Semaphore for blocking and wakeup */
 126     void (*start)(void); /* Start function */
 127 };
 128 #endif /* !SIMULATOR */
 129
 130 /* NOTE: The use of the word "queue" may also refer to a linked list of
 131    threads being maintained that are normally dealt with in FIFO order
 132    and not necessarily kernel event_queue */
 133 enum
 134 {
 135     /* States without a timeout must be first */
 136     STATE_KILLED = 0,    /* Thread is killed (default) */
 137     STATE_RUNNING,       /* Thread is currently running */
 138     STATE_BLOCKED,       /* Thread is indefinitely blocked on a queue */
 139     /* These states involve adding the thread to the tmo list */
 140     STATE_SLEEPING,      /* Thread is sleeping with a timeout */
 141     STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
 142     /* Miscellaneous states */
 143     STATE_FROZEN,        /* Thread is suspended and will not run until
 144                             thread_thaw is called with its ID */
 145     THREAD_NUM_STATES,
 146     TIMEOUT_STATE_FIRST = STATE_SLEEPING,
 147 };
 148
 149 #if NUM_CORES > 1
 150 /* Pointer value for name field to indicate thread is being killed. Using
 151  * an alternate STATE_* won't work since that would interfere with operation
 152  * while the thread is still running. */
 153 #define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
 154 #endif
 155
 156 /* Link information for lists thread is in */
 157 struct thread_entry; /* forward */
 158 struct thread_list
 159 {
 160     struct thread_entry *prev; /* Previous thread in a list */
 161     struct thread_entry *next; /* Next thread in a list */
 162 };
 163
 164 /* Small objects for core-wise mutual exclusion */
 165 #if CONFIG_CORELOCK == SW_CORELOCK
 166 /* No reliable atomic instruction available - use Peterson's algorithm */
 167 struct corelock
 168 {
 169     volatile unsigned char myl[NUM_CORES];
 170     volatile unsigned char turn;
 171 } __attribute__((packed));
 172
 173 void corelock_init(struct corelock *cl);
 174 void corelock_lock(struct corelock *cl);
 175 int corelock_try_lock(struct corelock *cl);
 176 void corelock_unlock(struct corelock *cl);
 177 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 178 /* Use native atomic swap/exchange instruction */
 179 struct corelock
 180 {
 181     volatile unsigned char locked;
 182 } __attribute__((packed));
 183
 184 #define corelock_init(cl) \
 185     ({ (cl)->locked = 0; })
 186 #define corelock_lock(cl) \
 187     ({ while (test_and_set(&(cl)->locked, 1)); })
 188 #define corelock_try_lock(cl) \
 189     ({ test_and_set(&(cl)->locked, 1) ? 0 : 1; })
 190 #define corelock_unlock(cl) \
 191     ({ (cl)->locked = 0; })
 192 #else
 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 /* core locking selection */
 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 #endif
 257     struct thread_entry *queue; /* List of threads waiting for thread to be
 258                                   removed */
 259 #ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
 260     #define HAVE_WAKEUP_EXT_CB
 261     void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
 262                                   performs special steps needed when being
 263                                   forced off of an object's wait queue that
 264                                   go beyond the standard wait queue removal
 265                                   and priority disinheritance */
 266     /* Only enabled when using queue_send for now */
 267 #endif
 268 #if defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || NUM_CORES > 1
 269     intptr_t retval;           /* Return value from a blocked operation/
 270                                   misc. use */
 271 #endif
 272 #ifdef HAVE_PRIORITY_SCHEDULING
 273     /* Priority summary of owned objects that support inheritance */
 274     struct blocker *blocker;   /* Pointer to blocker when this thread is blocked
 275                                   on an object that supports PIP -
 276                                   states: STATE_BLOCKED/STATE_BLOCKED_W_TMO  */
 277     struct priority_distribution pdist; /* Priority summary of owned objects
 278                                   that have blocked threads and thread's own
 279                                   base priority */
 280     int skip_count;            /* Number of times skipped if higher priority
 281                                   thread was running */
 282 #endif
 283     unsigned short stack_size; /* Size of stack in bytes */
 284 #ifdef HAVE_PRIORITY_SCHEDULING
 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     unsigned char state;       /* Thread slot state (STATE_*) */
 291 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 292     unsigned char cpu_boost;   /* CPU frequency boost flag */
 293 #endif
 294 #if NUM_CORES > 1
 295     unsigned char core;        /* The core to which thread belongs */
 296     struct corelock waiter_cl; /* Corelock for thread_wait */
 297     struct corelock slot_cl;   /* Corelock to lock thread slot */
 298 #endif
 299 };
 300
 301 #if NUM_CORES > 1
 302 /* Operations to be performed just before stopping a thread and starting
 303    a new one if specified before calling switch_thread */
 304 enum
 305 {
 306     TBOP_CLEAR = 0,       /* No operation to do */
 307     TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
 308     TBOP_SWITCH_CORE,     /* Call the core switch preparation routine */
 309 };
 310
 311 struct thread_blk_ops
 312 {
 313     struct corelock *cl_p;    /* pointer to corelock */
 314     unsigned char    flags;   /* TBOP_* flags */
 315 };
 316 #endif /* NUM_CORES > 1 */
 317
 318 /* Information kept for each core
 319  * Members are arranged for the same reason as in thread_entry
 320  */
 321 struct core_entry
 322 {
 323     /* "Active" lists - core is constantly active on these and are never
 324        locked and interrupts do not access them */
 325     struct thread_entry *running;  /* threads that are running (RTR) */
 326     struct thread_entry *timeout;  /* threads that are on a timeout before
 327                                       running again */
 328     struct thread_entry *block_task; /* Task going off running list */
 329 #ifdef HAVE_PRIORITY_SCHEDULING
 330     struct priority_distribution rtr; /* Summary of running and ready-to-run
 331                                          threads */
 332 #endif
 333     long next_tmo_check;           /* soonest time to check tmo threads */
 334 #if NUM_CORES > 1
 335     struct thread_blk_ops blk_ops; /* operations to perform when
 336                                       blocking a thread */
 337     struct corelock rtr_cl;        /* Lock for rtr list */
 338 #endif /* NUM_CORES */
 339 };
 340
 341 #ifdef HAVE_PRIORITY_SCHEDULING
 342 #define IF_PRIO(...)    __VA_ARGS__
 343 #define IFN_PRIO(...)
 344 #else
 345 #define IF_PRIO(...)
 346 #define IFN_PRIO(...)   __VA_ARGS__
 347 #endif
 348
 349 /* Macros generate better code than an inline function is this case */
 350 #if (defined (CPU_PP) || defined (CPU_ARM))
 351 /* atomic */
 352 #if CONFIG_CORELOCK == SW_CORELOCK
 353 #define test_and_set(a, v, cl) \
 354     xchg8((a), (v), (cl))
 355 /* atomic */
 356 #define xchg8(a, v, cl) \
 357 ({  uint32_t o;            \
 358     corelock_lock(cl);     \
 359     o = *(uint8_t *)(a);   \
 360     *(uint8_t *)(a) = (v); \
 361     corelock_unlock(cl);   \
 362     o; })
 363 #define xchg32(a, v, cl) \
 364 ({  uint32_t o;             \
 365     corelock_lock(cl);      \
 366     o = *(uint32_t *)(a);   \
 367     *(uint32_t *)(a) = (v); \
 368     corelock_unlock(cl);    \
 369     o; })
 370 #define xchgptr(a, v, cl) \
 371 ({  typeof (*(a)) o;     \
 372     corelock_lock(cl);   \
 373     o = *(a);            \
 374     *(a) = (v);          \
 375     corelock_unlock(cl); \
 376     o; })
 377 #elif CONFIG_CORELOCK == CORELOCK_SWAP
 378 /* atomic */
 379 #define test_and_set(a, v, ...) \
 380     xchg8((a), (v))
 381 #define xchg8(a, v, ...) \
 382 ({  uint32_t o;                \
 383     asm volatile(              \
 384         "swpb %0, %1, [%2]"    \
 385         : "=&r"(o)             \
 386         : "r"(v),              \
 387           "r"((uint8_t*)(a))); \
 388     o; })
 389 /* atomic */
 390 #define xchg32(a, v, ...) \
 391 ({  uint32_t o;                 \
 392     asm volatile(               \
 393         "swp %0, %1, [%2]"      \
 394         : "=&r"(o)              \
 395         : "r"((uint32_t)(v)),   \
 396           "r"((uint32_t*)(a))); \
 397     o; })
 398 /* atomic */
 399 #define xchgptr(a, v, ...) \
 400 ({  typeof (*(a)) o;        \
 401     asm volatile(           \
 402         "swp %0, %1, [%2]"  \
 403         : "=&r"(o)          \
 404         : "r"(v), "r"(a));  \
 405     o; })
 406 #endif /* locking selection */
 407 #elif defined (CPU_COLDFIRE)
 408 /* atomic */
 409 /* one branch will be optimized away if v is a constant expression */
 410 #define test_and_set(a, v, ...) \
 411 ({  uint32_t o = 0;                \
 412     if (v) {                       \
 413         asm volatile (             \
 414             "bset.b #0, (%0)"      \
 415             : : "a"((uint8_t*)(a)) \
 416             : "cc");               \
 417     } else {                       \
 418         asm volatile (             \
 419             "bclr.b #0, (%0)"      \
 420             : : "a"((uint8_t*)(a)) \
 421             : "cc");               \
 422     }                              \
 423     asm volatile ("sne.b %0"       \
 424         : "+d"(o));                \
 425     o; })
 426 #elif CONFIG_CPU == SH7034
 427 /* atomic */
 428 #define test_and_set(a, v, ...) \
 429 ({  uint32_t o;                 \
 430     asm volatile (              \
 431         "tas.b  @%2     \n"     \
 432         "mov    #-1, %0 \n"     \
 433         "negc   %0, %0  \n"     \
 434         : "=r"(o)               \
 435         : "M"((uint32_t)(v)),   /* Value of_v must be 1 */ \
 436           "r"((uint8_t *)(a))); \
 437     o; })
 438 #endif /* CONFIG_CPU == */
 439
 440 /* defaults for no asm version */
 441 #ifndef test_and_set
 442 /* not atomic */
 443 #define test_and_set(a, v, ...) \
 444 ({  uint32_t o = *(uint8_t *)(a); \
 445     *(uint8_t *)(a) = (v);        \
 446     o; })
 447 #endif /* test_and_set */
 448 #ifndef xchg8
 449 /* not atomic */
 450 #define xchg8(a, v, ...) \
 451 ({  uint32_t o = *(uint8_t *)(a); \
 452     *(uint8_t *)(a) = (v);        \
 453     o; })
 454 #endif /* xchg8 */
 455 #ifndef xchg32
 456 /* not atomic */
 457 #define xchg32(a, v, ...) \
 458 ({  uint32_t o = *(uint32_t *)(a); \
 459     *(uint32_t *)(a) = (v);        \
 460     o; })
 461 #endif /* xchg32 */
 462 #ifndef xchgptr
 463 /* not atomic */
 464 #define xchgptr(a, v, ...) \
 465 ({  typeof (*(a)) o = *(a); \
 466     *(a) = (v);             \
 467     o; })
 468 #endif /* xchgptr */
 469
 470 void core_idle(void);
 471 void core_wake(IF_COP_VOID(unsigned int core));
 472
 473 /* Initialize the scheduler */
 474 void init_threads(void);
 475
 476 /* Allocate a thread in the scheduler */
 477 #define CREATE_THREAD_FROZEN   0x00000001 /* Thread is frozen at create time */
 478 struct thread_entry*
 479     create_thread(void (*function)(void), void* stack, size_t stack_size,
 480                   unsigned flags, const char *name
 481                   IF_PRIO(, int priority)
 482                           IF_COP(, unsigned int core));
 483
 484 /* Set and clear the CPU frequency boost flag for the calling thread */
 485 #ifdef HAVE_SCHEDULER_BOOSTCTRL
 486 void trigger_cpu_boost(void);
 487 void cancel_cpu_boost(void);
 488 #else
 489 #define trigger_cpu_boost()
 490 #define cancel_cpu_boost()
 491 #endif
 492 /* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
 493  * Has no effect on a thread not frozen. */
 494 void thread_thaw(struct thread_entry *thread);
 495 /* Wait for a thread to exit */
 496 void thread_wait(struct thread_entry *thread);
 497 /* Exit the current thread */
 498 void thread_exit(void);
 499 #if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
 500 #define ALLOW_REMOVE_THREAD
 501 /* Remove a thread from the scheduler */
 502 void remove_thread(struct thread_entry *thread);
 503 #endif
 504
 505 /* Switch to next runnable thread */
 506 void switch_thread(void);
 507 /* Blocks a thread for at least the specified number of ticks (0 = wait until
 508  * next tick) */
 509 void sleep_thread(int ticks);
 510 /* Indefinitely blocks the current thread on a thread queue */
 511 void block_thread(struct thread_entry *current);
 512 /* Blocks the current thread on a thread queue until explicitely woken or
 513  * the timeout is reached */
 514 void block_thread_w_tmo(struct thread_entry *current, int timeout);
 515
 516 /* Return bit flags for thread wakeup */
 517 #define THREAD_NONE     0x0 /* No thread woken up (exclusive) */
 518 #define THREAD_OK       0x1 /* A thread was woken up */
 519 #define THREAD_SWITCH   0x2 /* Task switch recommended (one or more of
 520                                higher priority than current were woken) */
 521
 522 /* A convenience function for waking an entire queue of threads. */
 523 unsigned int thread_queue_wake(struct thread_entry **list);
 524
 525 /* Wakeup a thread at the head of a list */
 526 unsigned int wakeup_thread(struct thread_entry **list);
 527
 528 #ifdef HAVE_PRIORITY_SCHEDULING
 529 int thread_set_priority(struct thread_entry *thread, int priority);
 530 int thread_get_priority(struct thread_entry *thread);
 531 #endif /* HAVE_PRIORITY_SCHEDULING */
 532 #if NUM_CORES > 1
 533 unsigned int switch_core(unsigned int new_core);
 534 #endif
 535 struct thread_entry * thread_get_current(void);
 536
 537 /* Debugging info - only! */
 538 int thread_stack_usage(const struct thread_entry *thread);
 539 #if NUM_CORES > 1
 540 int idle_stack_usage(unsigned int core);
 541 #endif
 542 void thread_get_name(char *buffer, int size,
 543                      struct thread_entry *thread);
 544 #ifdef RB_PROFILE
 545 void profile_thread(void);
 546 #endif
 547
 548 #endif /* THREAD_H */