cond.c

xenomai 很好的linux实时补丁

	}

 unlock_and_exit:

    xnlock_put_irqrestore(&nklock,s);

    return err;
}

/**
 * @fn int rt_cond_broadcast(RT_COND *cond)
 * @brief Broadcast a condition variable.
 *
 * If the condition variable is pended, all tasks currently waiting on
 * it are immediately unblocked.
 *
 * @param cond The descriptor address of the affected condition
 * variable.
 *
 * @return 0 is returned upon success. Otherwise:
 *
 * - -EINVAL is returned if @a cond is not a condition variable
 * descriptor.
 *
 * - -EIDRM is returned if @a cond is a deleted condition variable
 * descriptor.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel module initialization/cleanup code
 * - Interrupt service routine
 * - Kernel-based task
 * - User-space task
 *
 * Rescheduling: possible.
 */

int rt_cond_broadcast (RT_COND *cond)

{
    int err = 0;
    spl_t s;

    xnlock_get_irqsave(&nklock,s);

    cond = xeno_h2obj_validate(cond,XENO_COND_MAGIC,RT_COND);

    if (!cond)
        {
        err = xeno_handle_error(cond,XENO_COND_MAGIC,RT_COND);
        goto unlock_and_exit;
        }

    if (xnsynch_flush(&cond->synch_base,0) == XNSYNCH_RESCHED)
	xnpod_schedule();

 unlock_and_exit:

    xnlock_put_irqrestore(&nklock,s);

    return err;
}

/**
 * @fn int rt_cond_wait(RT_COND *cond, RT_MUTEX *mutex, RTIME timeout)
 * @brief Wait on a condition.
 *
 * This service atomically release the mutex and causes the calling
 * task to block on the specified condition variable. The caller will
 * be unblocked when the variable is signaled, and the mutex
 * re-acquired before returning from this service.

 * Tasks pend on condition variables by priority order.
 *
 * @param cond The descriptor address of the affected condition
 * variable.
 *
 * @param mutex The descriptor address of the mutex protecting the
 * condition variable.
 *
 * @param timeout The number of clock ticks to wait for the condition
 * variable to be signaled (see note). Passing TM_INFINITE causes the
 * caller to block indefinitely until the condition variable is
 * signaled.
 *
 * @return 0 is returned upon success. Otherwise:
 *
 * - -EINVAL is returned if @a mutex is not a mutex descriptor, or @a
 * cond is not a condition variable descriptor.
 *
 * - -EIDRM is returned if @a mutex or @a cond is a deleted object
 * descriptor, including if the deletion occurred while the caller was
 * sleeping on the variable.
 *
 * - -EINTR is returned if rt_task_unblock() has been called for the
 * waiting task before the condition variable has been signaled.
 *
 * - -EWOULDBLOCK is returned if @a timeout equals TM_NONBLOCK.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel-based task
 * - User-space task (switches to primary mode)
 *
 * Rescheduling: always unless the request is immediately satisfied or
 * @a timeout specifies a non-blocking operation.
 *
 * @note This service is sensitive to the current operation mode of
 * the system timer, as defined by the rt_timer_start() service. In
 * periodic mode, clock ticks are interpreted as periodic jiffies. In
 * oneshot mode, clock ticks are interpreted as nanoseconds.
 */

int rt_cond_wait (RT_COND *cond,
		  RT_MUTEX *mutex,
		  RTIME timeout)
{
    RT_TASK *task;
    int err;
    spl_t s;

    if (timeout == TM_NONBLOCK)
	return -EWOULDBLOCK;
    
    xnlock_get_irqsave(&nklock,s);

    cond = xeno_h2obj_validate(cond,XENO_COND_MAGIC,RT_COND);

    if (!cond)
        {
        err = xeno_handle_error(cond,XENO_COND_MAGIC,RT_COND);
        goto unlock_and_exit;
        }

    err = rt_mutex_unlock(mutex);

    if (err)
	goto unlock_and_exit;

    task = xeno_current_task();

    xnsynch_sleep_on(&cond->synch_base,timeout);
        
    if (xnthread_test_flags(&task->thread_base,XNRMID))
	err = -EIDRM; /* Condvar deleted while pending. */
    else if (xnthread_test_flags(&task->thread_base,XNTIMEO))
	err = -ETIMEDOUT; /* Timeout.*/
    else if (xnthread_test_flags(&task->thread_base,XNBREAK))
	err = -EINTR; /* Unblocked.*/

    rt_mutex_lock(mutex,TM_INFINITE);

 unlock_and_exit:

    xnlock_put_irqrestore(&nklock,s);

    return err;
}

/**
 * @fn int rt_cond_inquire(RT_COND *cond, RT_COND_INFO *info)
 * @brief Inquire about a condition variable.
 *
 * Return various information about the status of a given condition
 * variable.
 *
 * @param cond The descriptor address of the inquired condition
 * variable.
 *
 * @param info The address of a structure the condition variable
 * information will be written to.

 * @return 0 is returned and status information is written to the
 * structure pointed at by @a info upon success. Otherwise:
 *
 * - -EINVAL is returned if @a cond is not a condition variable
 * descriptor.
 *
 * - -EIDRM is returned if @a cond is a deleted condition variable
 * descriptor.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel module initialization/cleanup code
 * - Interrupt service routine
 * - Kernel-based task
 * - User-space task
 *
 * Rescheduling: never.
 */

int rt_cond_inquire (RT_COND *cond,
		     RT_COND_INFO *info)
{
    int err = 0;
    spl_t s;

    xnlock_get_irqsave(&nklock,s);

    cond = xeno_h2obj_validate(cond,XENO_COND_MAGIC,RT_COND);

    if (!cond)
        {
        err = xeno_handle_error(cond,XENO_COND_MAGIC,RT_COND);
        goto unlock_and_exit;
        }
    
    strcpy(info->name,cond->name);
    info->nwaiters = xnsynch_nsleepers(&cond->synch_base);

 unlock_and_exit:

    xnlock_put_irqrestore(&nklock,s);

    return err;
}

/**
 * @fn int rt_cond_bind(RT_COND *cond, const char *name, RTIME timeout)
 * @brief Bind to a condition variable.
 *
 * This user-space only service retrieves the uniform descriptor of a
 * given Xenomai condition variable identified by its symbolic name. If
 * the condition variable does not exist on entry, this service blocks
 * the caller until a condition variable of the given name is created.
 *
 * @param name A valid NULL-terminated name which identifies the
 * condition variable to bind to.
 *
 * @param cond The address of a condition variable descriptor
 * retrieved by the operation. Contents of this memory is undefined
 * upon failure.
 *
 * @param timeout The number of clock ticks to wait for the
 * registration to occur (see note). Passing TM_INFINITE causes the
 * caller to block indefinitely until the object is
 * registered. Passing TM_NONBLOCK causes the service to return
 * immediately without waiting if the object is not registered on
 * entry.
 *
 * @return 0 is returned upon success. Otherwise:
 *
 * - -EFAULT is returned if @a cond or @a name is referencing invalid
 * memory.
 *
 * - -EINTR is returned if rt_task_unblock() has been called for the
 * waiting task before the retrieval has completed.
 *
 * - -EWOULDBLOCK is returned if @a timeout is equal to TM_NONBLOCK
 * and the searched object is not registered on entry.
 *
 * - -ETIMEDOUT is returned if the object cannot be retrieved within
 * the specified amount of time.
 *
 * - -EPERM is returned if this service should block, but was called
 * from a context which cannot sleep (e.g. interrupt, non-realtime or
 * scheduler locked).
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - User-space task (switches to primary mode)
 *
 * Rescheduling: always unless the request is immediately satisfied or
 * @a timeout specifies a non-blocking operation.
 *
 * @note This service is sensitive to the current operation mode of
 * the system timer, as defined by the rt_timer_start() service. In
 * periodic mode, clock ticks are interpreted as periodic jiffies. In
 * oneshot mode, clock ticks are interpreted as nanoseconds.
 */

/**
 * @fn int rt_cond_unbind(RT_COND *cond)
 *
 * @brief Unbind from a condition variable.
 *
 * This user-space only service unbinds the calling task from the
 * condition variable object previously retrieved by a call to
 * rt_cond_bind().
 *
 * @param cond The address of a condition variable descriptor to
 * unbind from.
 *
 * @return 0 is always returned.
 *
 * This service can be called from:
 *
 * - User-space task.
 *
 * Rescheduling: never.
 */

int __native_cond_pkg_init (void)

{
    return 0;
}

void __native_cond_pkg_cleanup (void)

{
}

/*@}*/

EXPORT_SYMBOL(rt_cond_create);
EXPORT_SYMBOL(rt_cond_delete);
EXPORT_SYMBOL(rt_cond_signal);
EXPORT_SYMBOL(rt_cond_broadcast);
EXPORT_SYMBOL(rt_cond_wait);
EXPORT_SYMBOL(rt_cond_inquire);