incubator-nuttx/mm/iob/iob_notifier.c

136 lines
4.5 KiB
C

/****************************************************************************
* mm/iob/iob_notifier.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <assert.h>
#include <nuttx/wqueue.h>
#include <nuttx/mm/iob.h>
#include "iob.h"
#ifdef CONFIG_IOB_NOTIFIER
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: iob_notifier_setup
*
* Description:
* Set up to perform a callback to the worker function when an IOB is
* available. The worker function will execute on the selected priority
* worker thread.
*
* Input Parameters:
* qid - Selects work queue. Must be HPWORK or LPWORK.
* worker - The worker function to execute on the high priority work queue
* when the event occurs.
* arg - A user-defined argument that will be available to the worker
* function when it runs.
*
* Returned Value:
* > 0 - The notification is in place. The returned value is a key that
* may be used later in a call to iob_notifier_teardown().
* == 0 - There are already free IOBs. No notification will be provided.
* < 0 - An unexpected error occurred and notification will occur. The
* returned value is a negated errno value that indicates the
* nature of the failure.
*
****************************************************************************/
int iob_notifier_setup(int qid, worker_t worker, FAR void *arg)
{
struct work_notifier_s info;
DEBUGASSERT(worker != NULL);
info.evtype = WORK_IOB_AVAIL;
info.qid = qid;
info.qualifier = NULL;
info.arg = arg;
info.worker = worker;
return work_notifier_setup(&info);
}
/****************************************************************************
* Name: iob_notifier_teardown
*
* Description:
* Eliminate an IOB notification previously setup by iob_notifier_setup().
* This function should only be called if the notification should be
* aborted prior to the notification. The notification will automatically
* be torn down after the notification.
*
* Input Parameters:
* key - The key value returned from a previous call to
* iob_notifier_setup().
*
* Returned Value:
* None.
*
****************************************************************************/
void iob_notifier_teardown(int key)
{
/* This is just a simple wrapper around work_notifier_teardown(). */
work_notifier_teardown(key);
}
/****************************************************************************
* Name: iob_notifier_signal
*
* Description:
* An IOB has become available. Signal all threads waiting for an IOB
* that an IOB is available.
*
* When an IOB becomes available, *all* of the workers waiting for an
* IOB will be executed. If there are multiple workers waiting for an IOB
* then only the first to execute will get the IOB. Others will
* need to call iob_notify_setup() once again.
*
* Input Parameters:
* None.
*
* Returned Value:
* None.
*
****************************************************************************/
void iob_notifier_signal(void)
{
/* This is just a simple wrapper around work_notifier_signal(). */
work_notifier_signal(WORK_IOB_AVAIL, NULL);
}
#endif /* CONFIG_IOB_NOTIFIER */