rockbox/firmware/kernel/include/thread.h
Michael Sevakis 81ffd9bfee Fix some stuff for no priority and
thread_queue_wake() doesn't need the 2nd parameter. The original purpose
for it never came to be.

Non priority version mrsw_writer_wakeup_readers was left improperly
finished. Get that back into line.

Change-Id: Ic613a2479f3cc14dc7c761517670eb15178da9f5
2014-08-06 02:27:49 -04:00

414 lines
16 KiB
C

/***************************************************************************
* __________ __ ___.
* 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>
#include "gcc_extensions.h"
#include "corelock.h"
#include "bitarray.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 */
#define IO_PRIORITY_IMMEDIATE 0
#define IO_PRIORITY_BACKGROUND 32
#if CONFIG_CODEC == SWCODEC
# ifdef HAVE_HARDWARE_CLICK
# define BASETHREADS 17
# else
# define BASETHREADS 16
# endif
#else
# define BASETHREADS 11
#endif /* CONFIG_CODE == * */
#ifndef TARGET_EXTRA_THREADS
#define TARGET_EXTRA_THREADS 0
#endif
#define MAXTHREADS (BASETHREADS+TARGET_EXTRA_THREADS)
BITARRAY_TYPE_DECLARE(threadbit_t, threadbit, MAXTHREADS)
BITARRAY_TYPE_DECLARE(priobit_t, priobit, NUM_PRIORITIES)
/*
* We need more stack when we run under a host
* maybe more expensive C lib functions?
*
* simulator (possibly) doesn't simulate stack usage anyway but well ... */
#if defined(HAVE_SDL_THREADS) || defined(__PCTOOL__)
struct regs
{
void *t; /* OS thread */
void *told; /* Last thread in slot (explained in thead-sdl.c) */
void *s; /* Semaphore for blocking and wakeup */
void (*start)(void); /* Start function */
};
#define DEFAULT_STACK_SIZE 0x100 /* tiny, ignored anyway */
#else
#include "asm/thread.h"
#endif /* HAVE_SDL_THREADS */
/* 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 */
};
/* Basic structure describing the owner of an object */
struct blocker
{
struct thread_entry * volatile thread; /* thread blocking other threads
(aka. object owner) */
#ifdef HAVE_PRIORITY_SCHEDULING
int priority; /* highest priority waiter */
#endif
};
/* If a thread has a blocker but the blocker's registered thread is NULL,
then it references this and the struct blocker pointer may be
reinterpreted as such. */
struct blocker_splay
{
struct blocker blocker; /* blocker info (first!) */
#ifdef HAVE_PRIORITY_SCHEDULING
threadbit_t mask; /* mask of nonzero tcounts */
#if NUM_CORES > 1
struct corelock cl; /* mutual exclusion */
#endif
#endif /* HAVE_PRIORITY_SCHEDULING */
};
#ifdef HAVE_PRIORITY_SCHEDULING
/* Quick-disinherit of priority elevation. Must be a running thread. */
void priority_disinherit(struct thread_entry *thread, struct blocker *bl);
struct priority_distribution
{
uint8_t hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
priobit_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 */
#ifdef HAVE_CORELOCK_OBJECT
struct corelock *obj_cl; /* Object corelock where thead is blocked -
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
struct corelock waiter_cl; /* Corelock for thread_wait */
struct corelock slot_cl; /* Corelock to lock thread slot */
unsigned char core; /* The core to which thread belongs */
#endif
struct thread_entry *queue; /* List of threads waiting for thread to be
removed */
#ifdef 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_SEMAPHORE_OBJECTS) || \
defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || \
NUM_CORES > 1
volatile intptr_t retval; /* Return value from a blocked operation/
misc. use */
#endif
uint32_t id; /* Current slot id */
int __errno; /* Thread error number (errno tls) */
#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 */
unsigned char base_priority; /* Base priority (set explicitly during
creation or thread_set_priority) */
unsigned char priority; /* Scheduled priority (higher of base or
all threads blocked by this one) */
#endif
unsigned short stack_size; /* Size of stack in bytes */
unsigned char state; /* Thread slot state (STATE_*) */
#ifdef HAVE_SCHEDULER_BOOSTCTRL
unsigned char cpu_boost; /* CPU frequency boost flag */
#endif
#ifdef HAVE_IO_PRIORITY
unsigned char io_priority;
#endif
};
/*** Macros for internal use ***/
/* Thread ID, 32 bits = |VVVVVVVV|VVVVVVVV|VVVVVVVV|SSSSSSSS| */
#define THREAD_ID_VERSION_SHIFT 8
#define THREAD_ID_VERSION_MASK 0xffffff00
#define THREAD_ID_SLOT_MASK 0x000000ff
#define THREAD_ID_INIT(n) ((1u << THREAD_ID_VERSION_SHIFT) | (n))
#define THREAD_ID_SLOT(id) ((id) & THREAD_ID_SLOT_MASK)
#ifdef HAVE_CORELOCK_OBJECT
/* Operations to be performed just before stopping a thread and starting
a new one if specified before calling switch_thread */
enum
{
TBOP_CLEAR = 0, /* No operation to do */
TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
TBOP_SWITCH_CORE, /* Call the core switch preparation routine */
};
struct thread_blk_ops
{
struct corelock *cl_p; /* pointer to corelock */
unsigned char flags; /* TBOP_* flags */
};
#endif /* NUM_CORES > 1 */
/* Information kept for each core
* Members are arranged for the same reason as in thread_entry
*/
struct core_entry
{
/* "Active" lists - core is constantly active on these and are never
locked and interrupts do not access them */
struct thread_entry *running; /* threads that are running (RTR) */
struct thread_entry *timeout; /* threads that are on a timeout before
running again */
struct thread_entry *block_task; /* Task going off running list */
#ifdef HAVE_PRIORITY_SCHEDULING
struct priority_distribution rtr; /* Summary of running and ready-to-run
threads */
#endif
long next_tmo_check; /* soonest time to check tmo threads */
#ifdef HAVE_CORELOCK_OBJECT
struct thread_blk_ops blk_ops; /* operations to perform when
blocking a thread */
struct corelock rtr_cl; /* Lock for rtr list */
#endif /* NUM_CORES */
};
extern void yield(void);
extern unsigned sleep(unsigned ticks);
#ifdef HAVE_PRIORITY_SCHEDULING
#define IF_PRIO(...) __VA_ARGS__
#define IFN_PRIO(...)
#else
#define IF_PRIO(...)
#define IFN_PRIO(...) __VA_ARGS__
#endif
void core_idle(void);
void core_wake(IF_COP_VOID(unsigned int core));
/* Initialize the scheduler */
void init_threads(void) INIT_ATTR;
/* Allocate a thread in the scheduler */
#define CREATE_THREAD_FROZEN 0x00000001 /* Thread is frozen at create time */
unsigned int create_thread(void (*function)(void),
void* stack, size_t stack_size,
unsigned flags, const char *name
IF_PRIO(, int priority)
IF_COP(, unsigned int core));
/* Set and clear the CPU frequency boost flag for the calling thread */
#ifdef HAVE_SCHEDULER_BOOSTCTRL
void trigger_cpu_boost(void);
void cancel_cpu_boost(void);
#else
#define trigger_cpu_boost() do { } while(0)
#define cancel_cpu_boost() do { } while(0)
#endif
/* Return thread entry from id */
struct thread_entry *thread_id_entry(unsigned int thread_id);
/* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
* Has no effect on a thread not frozen. */
void thread_thaw(unsigned int thread_id);
/* Wait for a thread to exit */
void thread_wait(unsigned int thread_id);
/* Exit the current thread */
void thread_exit(void) NORETURN_ATTR;
#if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
#define ALLOW_REMOVE_THREAD
/* Remove a thread from the scheduler */
void remove_thread(unsigned int thread_id);
#endif
/* Switch to next runnable thread */
void switch_thread(void);
/* Blocks a thread for at least the specified number of ticks (0 = wait until
* next tick) */
void sleep_thread(int ticks);
/* Blocks the current thread on a thread queue (< 0 == infinite) */
void block_thread(struct thread_entry *current, int timeout);
/* Return bit flags for thread wakeup */
#define THREAD_NONE 0x0 /* No thread woken up (exclusive) */
#define THREAD_OK 0x1 /* A thread was woken up */
#define THREAD_SWITCH 0x2 /* Task switch recommended (one or more of
higher priority than current were woken) */
/* A convenience function for waking an entire queue of threads. */
unsigned int thread_queue_wake(struct thread_entry **list);
/* Wakeup a thread at the head of a list */
enum wakeup_thread_protocol
{
WAKEUP_DEFAULT,
WAKEUP_TRANSFER,
WAKEUP_RELEASE,
WAKEUP_TRANSFER_MULTI,
};
unsigned int wakeup_thread_(struct thread_entry **list
IF_PRIO(, enum wakeup_thread_protocol proto));
#ifdef HAVE_PRIORITY_SCHEDULING
#define wakeup_thread(list, proto) \
wakeup_thread_((list), (proto))
int thread_set_priority(unsigned int thread_id, int priority);
int thread_get_priority(unsigned int thread_id);
#else /* !HAVE_PRIORITY_SCHEDULING */
#define wakeup_thread(list, proto...) \
wakeup_thread_((list));
#endif /* HAVE_PRIORITY_SCHEDULING */
#ifdef HAVE_IO_PRIORITY
void thread_set_io_priority(unsigned int thread_id, int io_priority);
int thread_get_io_priority(unsigned int thread_id);
#endif /* HAVE_IO_PRIORITY */
#if NUM_CORES > 1
unsigned int switch_core(unsigned int new_core);
#endif
/* Return the id of the calling thread. */
unsigned int thread_self(void);
/* Return the thread_entry for the calling thread.
* INTERNAL: Intended for use by kernel and not for programs. */
struct thread_entry* thread_self_entry(void);
/* Debugging info - only! */
int thread_stack_usage(const struct thread_entry *thread);
#if NUM_CORES > 1
int idle_stack_usage(unsigned int core);
#endif
void thread_get_name(char *buffer, int size,
struct thread_entry *thread);
#ifdef RB_PROFILE
void profile_thread(void);
#endif
#endif /* THREAD_H */