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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Ulf Ralberg
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef THREAD_H
#define THREAD_H
#include "config.h"
#include <inttypes.h>
#include <stddef.h>
#include <stdbool.h>
/* Priority scheduling (when enabled with HAVE_PRIORITY_SCHEDULING) works
* by giving high priority threads more CPU time than lower priority threads
* when they need it. Priority is differential such that the priority
* difference between a lower priority runnable thread and the highest priority
* runnable thread determines the amount of aging necessary for the lower
* priority thread to be scheduled in order to prevent starvation.
*
* If software playback codec pcm buffer is going down to critical, codec
* can gradually raise its own priority to override user interface and
* prevent playback skipping.
*/
#define PRIORITY_RESERVED_HIGH 0 /* Reserved */
#define PRIORITY_RESERVED_LOW 32 /* Reserved */
#define HIGHEST_PRIORITY 1 /* The highest possible thread priority */
#define LOWEST_PRIORITY 31 /* The lowest possible thread priority */
/* Realtime range reserved for threads that will not allow threads of lower
* priority to age and run (future expansion) */
#define PRIORITY_REALTIME_1 1
#define PRIORITY_REALTIME_2 2
#define PRIORITY_REALTIME_3 3
#define PRIORITY_REALTIME_4 4
#define PRIORITY_REALTIME 4 /* Lowest realtime range */
#define PRIORITY_BUFFERING 15 /* Codec buffering thread */
#define PRIORITY_USER_INTERFACE 16 /* The main thread */
#define PRIORITY_RECORDING 16 /* Recording thread */
#define PRIORITY_PLAYBACK 16 /* Variable between this and MAX */
#define PRIORITY_PLAYBACK_MAX 5 /* Maximum allowable playback priority */
#define PRIORITY_SYSTEM 18 /* All other firmware threads */
#define PRIORITY_BACKGROUND 20 /* Normal application threads */
#define NUM_PRIORITIES 32
#define PRIORITY_IDLE 32 /* Priority representative of no tasks */
/* TODO: Only a minor tweak to create_thread would be needed to let
* thread slots be caller allocated - no essential threading functionality
* depends upon an array */
#if CONFIG_CODEC == SWCODEC
#ifdef HAVE_RECORDING
#define BASETHREADS 18
#else
#define BASETHREADS 17
#endif
#else
#define BASETHREADS 11
#endif /* CONFIG_CODE == * */
#ifndef TARGET_EXTRA_THREADS
#define TARGET_EXTRA_THREADS 0
#endif
#define MAXTHREADS (BASETHREADS+TARGET_EXTRA_THREADS)
#define DEFAULT_STACK_SIZE 0x400 /* Bytes */
#ifndef SIMULATOR
/* Need to keep structures inside the header file because debug_menu
* needs them. */
#ifdef CPU_COLDFIRE
struct regs
{
uint32_t macsr; /* 0 - EMAC status register */
uint32_t d[6]; /* 4-24 - d2-d7 */
uint32_t a[5]; /* 28-44 - a2-a6 */
uint32_t sp; /* 48 - Stack pointer (a7) */
uint32_t start; /* 52 - Thread start address, or NULL when started */
};
#elif CONFIG_CPU == SH7034
struct regs
{
uint32_t r[7]; /* 0-24 - Registers r8 thru r14 */
uint32_t sp; /* 28 - Stack pointer (r15) */
uint32_t pr; /* 32 - Procedure register */
uint32_t start; /* 36 - Thread start address, or NULL when started */
};
#elif defined(CPU_ARM)
struct regs
{
uint32_t r[8]; /* 0-28 - Registers r4-r11 */
uint32_t sp; /* 32 - Stack pointer (r13) */
uint32_t lr; /* 36 - r14 (lr) */
uint32_t start; /* 40 - Thread start address, or NULL when started */
};
#elif defined(CPU_MIPS)
struct regs
{
uint32_t r[27]; /* 0-104 - Registers $1, v0-v1, a0-a3, t0-t9, s0-s7, gp, fp */
uint32_t sp; /* 108 - Stack pointer */
uint32_t ra; /* 112 - Return address */
uint32_t start; /* 116 - Thread start address, or NULL when started */
};
#endif /* CONFIG_CPU */
#else
struct regs
{
void *t; /* Simulator OS thread */
void *s; /* Semaphore for blocking and wakeup */
void (*start)(void); /* Start function */
};
#endif /* !SIMULATOR */
/* NOTE: The use of the word "queue" may also refer to a linked list of
threads being maintained that are normally dealt with in FIFO order
and not necessarily kernel event_queue */
enum
{
/* States without a timeout must be first */
STATE_KILLED = 0, /* Thread is killed (default) */
STATE_RUNNING, /* Thread is currently running */
STATE_BLOCKED, /* Thread is indefinitely blocked on a queue */
/* These states involve adding the thread to the tmo list */
STATE_SLEEPING, /* Thread is sleeping with a timeout */
STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
/* Miscellaneous states */
STATE_FROZEN, /* Thread is suspended and will not run until
thread_thaw is called with its ID */
THREAD_NUM_STATES,
TIMEOUT_STATE_FIRST = STATE_SLEEPING,
};
#if NUM_CORES > 1
/* Pointer value for name field to indicate thread is being killed. Using
* an alternate STATE_* won't work since that would interfere with operation
* while the thread is still running. */
#define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
#endif
/* Link information for lists thread is in */
struct thread_entry; /* forward */
struct thread_list
{
struct thread_entry *prev; /* Previous thread in a list */
struct thread_entry *next; /* Next thread in a list */
};
/* Small objects for core-wise mutual exclusion */
#if CONFIG_CORELOCK == SW_CORELOCK
/* No reliable atomic instruction available - use Peterson's algorithm */
struct corelock
{
volatile unsigned char myl[NUM_CORES];
volatile unsigned char turn;
} __attribute__((packed));
void corelock_init(struct corelock *cl);
void corelock_lock(struct corelock *cl);
int corelock_try_lock(struct corelock *cl);
void corelock_unlock(struct corelock *cl);
#elif CONFIG_CORELOCK == CORELOCK_SWAP
/* Use native atomic swap/exchange instruction */
struct corelock
{
volatile unsigned char locked;
} __attribute__((packed));
#define corelock_init(cl) \
({ (cl)->locked = 0; })
#define corelock_lock(cl) \
({ while (test_and_set(&(cl)->locked, 1)); })
#define corelock_try_lock(cl) \
({ test_and_set(&(cl)->locked, 1) ? 0 : 1; })
#define corelock_unlock(cl) \
({ (cl)->locked = 0; })
#else
/* No atomic corelock op needed or just none defined */
#define corelock_init(cl)
#define corelock_lock(cl)
#define corelock_try_lock(cl)
#define corelock_unlock(cl)
#endif /* core locking selection */
#ifdef HAVE_PRIORITY_SCHEDULING
struct blocker
{
struct thread_entry *thread; /* thread blocking other threads
(aka. object owner) */
int priority; /* highest priority waiter */
struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
};
/* Choices of wakeup protocol */
/* For transfer of object ownership by one thread to another thread by
* the owning thread itself (mutexes) */
struct thread_entry *
wakeup_priority_protocol_transfer(struct thread_entry *thread);
/* For release by owner where ownership doesn't change - other threads,
* interrupts, timeouts, etc. (mutex timeout, queues) */
struct thread_entry *
wakeup_priority_protocol_release(struct thread_entry *thread);
struct priority_distribution
{
uint8_t hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
uint32_t mask; /* Bitmask of hist entries that are not zero */
};
#endif /* HAVE_PRIORITY_SCHEDULING */
/* Information kept in each thread slot
* members are arranged according to size - largest first - in order
* to ensure both alignment and packing at the same time.
*/
struct thread_entry
{
struct regs context; /* Register context at switch -
_must_ be first member */
uintptr_t *stack; /* Pointer to top of stack */
const char *name; /* Thread name */
long tmo_tick; /* Tick when thread should be woken from
timeout -
states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
struct thread_list l; /* Links for blocked/waking/running -
circular linkage in both directions */
struct thread_list tmo; /* Links for timeout list -
Circular in reverse direction, NULL-terminated in
forward direction -
states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
struct thread_entry **bqp; /* Pointer to list variable in kernel
object where thread is blocked - used
for implicit unblock and explicit wake
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
#if NUM_CORES > 1
struct corelock *obj_cl; /* Object corelock where thead is blocked -
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
#endif
struct thread_entry *queue; /* List of threads waiting for thread to be
removed */
#ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
#define HAVE_WAKEUP_EXT_CB
void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
performs special steps needed when being
forced off of an object's wait queue that
go beyond the standard wait queue removal
and priority disinheritance */
/* Only enabled when using queue_send for now */
#endif
#if defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || NUM_CORES > 1
intptr_t retval; /* Return value from a blocked operation/
misc. use */
#endif
#ifdef HAVE_PRIORITY_SCHEDULING
/* Priority summary of owned objects that support inheritance */
struct blocker *blocker; /* Pointer to blocker when this thread is blocked
on an object that supports PIP -
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
struct priority_distribution pdist; /* Priority summary of owned objects
that have blocked threads and thread's own
base priority */
int skip_count; /* Number of times skipped if higher priority
thread was running */
#endif
unsigned short stack_size; /* Size of stack in bytes */
#ifdef HAVE_PRIORITY_SCHEDULING
|