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rockbox/firmware/export/thread.h
Nicolas Pennequin 3e3c43c747 Finally commit Metadata on Buffer! 
buffering.c and buffering.h implement the new buffering API. playback.c is translated to that API. For more information about the whole concept, see http://www.rockbox.org/wiki/MetadataOnBuffer.
There should be no major visible changes, but most existing bugs remain (though fixing them should be easier now that playback.c is a bit less complex) and there probably will be new ones. Please report any problem!
Next step is to adapt cuesheet support, which is partly disabled here, and of course fix as much bugs as possible.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15306 a1c6a512-1295-4272-9138-f99709370657
2007-10-25 21:27:45 +00:00

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Ulf Ralberg
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* 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 less priority threads
* when they need it.
*
* If software playback codec pcm buffer is going down to critical, codec
* can change it own priority to REALTIME to override user interface and
* prevent playback skipping.
*/
#define HIGHEST_PRIORITY 1 /* The highest possible thread priority */
#define LOWEST_PRIORITY 100 /* The lowest possible thread priority */
#define PRIORITY_REALTIME 1
#define PRIORITY_USER_INTERFACE 4 /* The main thread */
#define PRIORITY_RECORDING 4 /* Recording thread */
#define PRIORITY_PLAYBACK 4 /* or REALTIME when needed */
#define PRIORITY_BUFFERING 4 /* Codec buffering thread */
#define PRIORITY_SYSTEM 6 /* All other firmware threads */
#define PRIORITY_BACKGROUND 8 /* Normal application threads */
#if CONFIG_CODEC == SWCODEC
#define MAXTHREADS 17
#else
#define MAXTHREADS 11
#endif
#define DEFAULT_STACK_SIZE 0x400 /* Bytes */
/**
* "Busy" values that can be swapped into a variable to indicate
* that the variable or object pointed to is in use by another processor
* core. When accessed, the busy value is swapped-in while the current
* value is atomically returned. If the swap returns the busy value,
* the processor should retry the operation until some other value is
* returned. When modification is finished, the new value should be
* written which unlocks it and updates it atomically.
*
* Procedure:
* while ((curr_value = swap(&variable, BUSY_VALUE)) == BUSY_VALUE);
*
* Modify/examine object at mem location or variable. Create "new_value"
* as suitable.
*
* variable = new_value or curr_value;
*
* To check a value for busy and perform an operation if not:
* curr_value = swap(&variable, BUSY_VALUE);
*
* if (curr_value != BUSY_VALUE)
* {
* Modify/examine object at mem location or variable. Create "new_value"
* as suitable.
* variable = new_value or curr_value;
* }
* else
* {
* Do nothing - already busy
* }
*
* Only ever restore when an actual value is returned or else it could leave
* the variable locked permanently if another processor unlocked in the
* meantime. The next access attempt would deadlock for all processors since
* an abandoned busy status would be left behind.
*/
#define STATE_BUSYuptr ((void*)UINTPTR_MAX)
#define STATE_BUSYu8 UINT8_MAX
#define STATE_BUSYi INT_MIN
#ifndef SIMULATOR
/* Need to keep structures inside the header file because debug_menu
* needs them. */
#ifdef CPU_COLDFIRE
struct regs
{
unsigned int macsr; /* 0 - EMAC status register */
unsigned int d[6]; /* 4-24 - d2-d7 */
unsigned int a[5]; /* 28-44 - a2-a6 */
void *sp; /* 48 - Stack pointer (a7) */
void *start; /* 52 - Thread start address, or NULL when started */
};
#elif CONFIG_CPU == SH7034
struct regs
{
unsigned int r[7]; /* 0-24 - Registers r8 thru r14 */
void *sp; /* 28 - Stack pointer (r15) */
void *pr; /* 32 - Procedure register */
void *start; /* 36 - Thread start address, or NULL when started */
};
#elif defined(CPU_ARM)
struct regs
{
unsigned int r[8]; /* 0-28 - Registers r4-r11 */
void *sp; /* 32 - Stack pointer (r13) */
unsigned int lr; /* 36 - r14 (lr) */
void *start; /* 40 - Thread start address, or NULL when started */
};
#endif /* CONFIG_CPU */
#else
struct regs
{
void *t; /* Simulator OS thread */
void *c; /* Condition for blocking and sync */
void (*start)(void); /* Start function */
};
#endif /* !SIMULATOR */
/* NOTE: The use of the word "queue" may also refer to a linked list of
threads being maintainted that are normally dealt with in FIFO order
and not nescessarily 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
STATE_BUSY = STATE_BUSYu8, /* Thread slot is being examined */
#endif
};
#if NUM_CORES > 1
#define THREAD_DESTRUCT ((const char *)0x84905617)
#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
{
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 */
struct thread_queue
{
struct thread_entry *queue; /* list of threads waiting -
_must_ be first member */
#if CONFIG_CORELOCK == SW_CORELOCK
struct corelock cl; /* lock for atomic list operations */
#endif
};
/* 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 */
void *stack; /* Pointer to top of stack */
const char *name; /* Thread name */
long tmo_tick; /* Tick when thread should be woken from
timeout */
struct thread_list l; /* Links for blocked/waking/running -
circular linkage in both directions */
struct thread_list tmo; /* Links for timeout list -
Self-pointer-terminated in reverse direction,
NULL-terminated in forward direction */
struct thread_queue *bqp; /* Pointer to list variable in kernel
object where thread is blocked - used
for implicit unblock and explicit wake */
#if CONFIG_CORELOCK == SW_CORELOCK
struct thread_entry **bqnlp; /* Pointer to list variable in kernel
object where thread is blocked - non-locked
operations will be used */
#endif
struct thread_entry *queue; /* List of threads waiting for thread to be
removed */
#ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
intptr_t retval; /* Return value from a blocked operation */
#endif
#ifdef HAVE_PRIORITY_SCHEDULING
long last_run; /* Last tick when started */
#endif
unsigned short stack_size; /* Size of stack in bytes */
#ifdef HAVE_PRIORITY_SCHEDULING
unsigned char priority; /* Current priority */
unsigned char priority_x; /* Inherited priority - right now just a
runtime guarantee flag */
#endif
unsigned char state; /* Thread slot state (STATE_*) */
#if NUM_CORES > 1
unsigned char core; /* The core to which thread belongs */
#endif
#ifdef HAVE_SCHEDULER_BOOSTCTRL
unsigned char boosted; /* CPU frequency boost flag */
#endif
#if CONFIG_CORELOCK == SW_CORELOCK
struct corelock cl; /* Corelock to lock thread slot */
#endif
};
#if NUM_CORES > 1
/* Operations to be performed just before stopping a thread and starting
a new one if specified before calling switch_thread */
#define TBOP_UNLOCK_LIST 0x01 /* Set a pointer variable address var_ptrp */
#if CONFIG_CORELOCK == CORELOCK_SWAP
#define TBOP_SET_VARi 0x02 /* Set an int at address var_ip */
#define TBOP_SET_VARu8 0x03 /* Set an unsigned char at address var_u8p */
#define TBOP_VAR_TYPE_MASK 0x03 /* Mask for variable type*/
#endif /* CONFIG_CORELOCK */
#define TBOP_UNLOCK_CORELOCK 0x04
#define TBOP_UNLOCK_THREAD 0x08 /* Unlock a thread's slot */
#define TBOP_UNLOCK_CURRENT 0x10 /* Unlock the current thread's slot */
#define TBOP_IRQ_LEVEL 0x20 /* Set a new irq level */
#define TBOP_SWITCH_CORE 0x40 /* Call the core switch preparation routine */
struct thread_blk_ops
{
int irq_level; /* new IRQ level to set */
#if CONFIG_CORELOCK != SW_CORELOCK
union
{
int var_iv; /* int variable value to set */
uint8_t var_u8v; /* unsigned char valur to set */
struct thread_entry *list_v; /* list pointer queue value to set */
};
#endif
union
{
#if CONFIG_CORELOCK != SW_CORELOCK
int *var_ip; /* pointer to int variable */
uint8_t *var_u8p; /* pointer to unsigned char varuable */
#endif
struct thread_queue *list_p; /* pointer to list variable */
};
#if CONFIG_CORELOCK == SW_CORELOCK
struct corelock *cl_p; /* corelock to unlock */
struct thread_entry *thread; /* thread to unlock */
#elif CONFIG_CORELOCK == CORELOCK_SWAP
unsigned char state; /* new thread state (performs unlock) */
#endif /* SOFTWARE_CORELOCK */
unsigned char flags; /* TBOP_* flags */
};
#endif /* NUM_CORES > 1 */
/* Information kept for each core
* Member 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 */
struct thread_entry *timeout; /* threads that are on a timeout before
running again */
/* "Shared" lists - cores interact in a synchronized manner - access
is locked between cores and interrupts */
struct thread_queue waking; /* intermediate locked list that
hold threads other core should wake up
on next task switch */
long next_tmo_check; /* soonest time to check tmo threads */
#if NUM_CORES > 1
struct thread_blk_ops blk_ops; /* operations to perform when
blocking a thread */
#else
#define STAY_IRQ_LEVEL (-1)
int irq_level; /* sets the irq level to irq_level */
#endif /* NUM_CORES */
#ifdef HAVE_PRIORITY_SCHEDULING
unsigned char highest_priority;
#endif
};
#ifdef HAVE_PRIORITY_SCHEDULING
#define IF_PRIO(...) __VA_ARGS__
#else
#define IF_PRIO(...)
#endif
/* Macros generate better code than an inline function is this case */
#if (defined (CPU_PP) || defined (CPU_ARM))
/* atomic */
#if CONFIG_CORELOCK == SW_CORELOCK
#define test_and_set(a, v, cl) \
xchg8((a), (v), (cl))
/* atomic */
#define xchg8(a, v, cl) \
({ uint32_t o; \
corelock_lock(cl); \
o = *(uint8_t *)(a); \
*(uint8_t *)(a) = (v); \
corelock_unlock(cl); \
o; })
#define xchg32(a, v, cl) \
({ uint32_t o; \
corelock_lock(cl); \
o = *(uint32_t *)(a); \
*(uint32_t *)(a) = (v); \
corelock_unlock(cl); \
o; })
#define xchgptr(a, v, cl) \
({ typeof (*(a)) o; \
corelock_lock(cl); \
o = *(a); \
*(a) = (v); \
corelock_unlock(cl); \
o; })
#elif CONFIG_CORELOCK == CORELOCK_SWAP
/* atomic */
#define test_and_set(a, v, ...) \
xchg8((a), (v))
#define xchg8(a, v, ...) \
({ uint32_t o; \
asm volatile( \
"swpb %0, %1, [%2]" \
: "=&r"(o) \
: "r"(v), \
"r"((uint8_t*)(a))); \
o; })
/* atomic */
#define xchg32(a, v, ...) \
({ uint32_t o; \
asm volatile( \
"swp %0, %1, [%2]" \
: "=&r"(o) \
: "r"((uint32_t)(v)), \
"r"((uint32_t*)(a))); \
o; })
/* atomic */
#define xchgptr(a, v, ...) \
({ typeof (*(a)) o; \
asm volatile( \
"swp %0, %1, [%2]" \
: "=&r"(o) \
: "r"(v), "r"(a)); \
o; })
#endif /* locking selection */
#elif defined (CPU_COLDFIRE)
/* atomic */
/* one branch will be optimized away if v is a constant expression */
#define test_and_set(a, v, ...) \
({ uint32_t o = 0; \
if (v) { \
asm volatile ( \
"bset.b #0, (%0)" \
: : "a"((uint8_t*)(a)) \
: "cc"); \
} else { \
asm volatile ( \
"bclr.b #0, (%0)" \
: : "a"((uint8_t*)(a)) \
: "cc"); \
} \
asm volatile ("sne.b %0" \
: "+d"(o)); \
o; })
#elif CONFIG_CPU == SH7034
/* atomic */
#define test_and_set(a, v, ...) \
({ uint32_t o; \
asm volatile ( \
"tas.b @%2 \n" \
"mov #-1, %0 \n" \
"negc %0, %0 \n" \
: "=r"(o) \
: "M"((uint32_t)(v)), /* Value of_v must be 1 */ \
"r"((uint8_t *)(a))); \
o; })
#endif /* CONFIG_CPU == */
/* defaults for no asm version */
#ifndef test_and_set
/* not atomic */
#define test_and_set(a, v, ...) \
({ uint32_t o = *(uint8_t *)(a); \
*(uint8_t *)(a) = (v); \
o; })
#endif /* test_and_set */
#ifndef xchg8
/* not atomic */
#define xchg8(a, v, ...) \
({ uint32_t o = *(uint8_t *)(a); \
*(uint8_t *)(a) = (v); \
o; })
#endif /* xchg8 */
#ifndef xchg32
/* not atomic */
#define xchg32(a, v, ...) \
({ uint32_t o = *(uint32_t *)(a); \
*(uint32_t *)(a) = (v); \
o; })
#endif /* xchg32 */
#ifndef xchgptr
/* not atomic */
#define xchgptr(a, v, ...) \
({ typeof (*(a)) o = *(a); \
*(a) = (v); \
o; })
#endif /* xchgptr */
void core_idle(void);
void core_wake(IF_COP_VOID(unsigned int core));
#define CREATE_THREAD_FROZEN 0x00000001 /* Thread is frozen at create time */
struct thread_entry*
create_thread(void (*function)(void), void* stack, int stack_size,
unsigned flags, const char *name
IF_PRIO(, int priority)
IF_COP(, unsigned int core));
#ifdef HAVE_SCHEDULER_BOOSTCTRL
void trigger_cpu_boost(void);
#else
#define trigger_cpu_boost()
#endif
void thread_thaw(struct thread_entry *thread);
void thread_wait(struct thread_entry *thread);
void remove_thread(struct thread_entry *thread);
void switch_thread(struct thread_entry *old);
void sleep_thread(int ticks);
/**
* Setup to allow using thread queues as locked or non-locked without speed
* sacrifices in both core locking types.
*
* The blocking/waking function inline two different version of the real
* function into the stubs when a software or other separate core locking
* mechanism is employed.
*
* When a simple test-and-set or similar instruction is available, locking
* has no cost and so one version is used and the internal worker is called
* directly.
*
* CORELOCK_NONE is treated the same as when an atomic instruction can be
* used.
*/
/* Blocks the current thread on a thread queue */
#if CONFIG_CORELOCK == SW_CORELOCK
void block_thread(struct thread_queue *tq);
void block_thread_no_listlock(struct thread_entry **list);
#else
void _block_thread(struct thread_queue *tq);
static inline void block_thread(struct thread_queue *tq)
{ _block_thread(tq); }
static inline void block_thread_no_listlock(struct thread_entry **list)
{ _block_thread((struct thread_queue *)list); }
#endif /* CONFIG_CORELOCK */
/* Blocks the current thread on a thread queue for a max amount of time
* There is no "_no_listlock" version because timeout blocks without sync on
* the blocking queues is not permitted since either core could access the
* list at any time to do an implicit wake. In other words, objects with
* timeout support require lockable queues. */
void block_thread_w_tmo(struct thread_queue *tq, int timeout);
/* Wakes up the thread at the head of the queue */
#define THREAD_WAKEUP_NONE ((struct thread_entry *)NULL)
#define THREAD_WAKEUP_MISSING ((struct thread_entry *)(NULL+1))
#if CONFIG_CORELOCK == SW_CORELOCK
struct thread_entry * wakeup_thread(struct thread_queue *tq);
struct thread_entry * wakeup_thread_no_listlock(struct thread_entry **list);
#else
struct thread_entry * _wakeup_thread(struct thread_queue *list);
static inline struct thread_entry * wakeup_thread(struct thread_queue *tq)
{ return _wakeup_thread(tq); }
static inline struct thread_entry * wakeup_thread_no_listlock(struct thread_entry **list)
{ return _wakeup_thread((struct thread_queue *)list); }
#endif /* CONFIG_CORELOCK */
/* Initialize a thread_queue object. */
static inline void thread_queue_init(struct thread_queue *tq)
{ tq->queue = NULL; IF_SWCL(corelock_init(&tq->cl);) }
/* A convenience function for waking an entire queue of threads. */
static inline void thread_queue_wake(struct thread_queue *tq)
{ while (wakeup_thread(tq) != NULL); }
/* The no-listlock version of thread_queue_wake() */
static inline void thread_queue_wake_no_listlock(struct thread_entry **list)
{ while (wakeup_thread_no_listlock(list) != NULL); }
#ifdef HAVE_PRIORITY_SCHEDULING
int thread_set_priority(struct thread_entry *thread, int priority);
int thread_get_priority(struct thread_entry *thread);
/* Yield that guarantees thread execution once per round regardless of
thread's scheduler priority - basically a transient realtime boost
without altering the scheduler's thread precedence. */
void priority_yield(void);
#else
#define priority_yield yield
#endif /* HAVE_PRIORITY_SCHEDULING */
#if NUM_CORES > 1
unsigned int switch_core(unsigned int new_core);
#endif
struct thread_entry * thread_get_current(void);
void init_threads(void);
int thread_stack_usage(const struct thread_entry *thread);
#if NUM_CORES > 1
int idle_stack_usage(unsigned int core);
#endif
unsigned thread_get_status(const struct thread_entry *thread);
void thread_get_name(char *buffer, int size,
struct thread_entry *thread);
#ifdef RB_PROFILE
void profile_thread(void);
#endif
#endif /* THREAD_H */
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