nuttx/libs/libc/wqueue/work_usrthread.c

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/****************************************************************************
* libs/libc/wqueue/work_usrthread.c
*
* 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 <stdint.h>
#include <unistd.h>
#include <pthread.h>
#include <sched.h>
#include <errno.h>
#include <assert.h>
#include <queue.h>
#include <nuttx/semaphore.h>
#include <nuttx/clock.h>
#include <nuttx/wqueue.h>
#include "wqueue/wqueue.h"
#if defined(CONFIG_LIBC_USRWORK) && !defined(__KERNEL__)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifdef CONFIG_SYSTEM_TIME64
# define WORK_DELAY_MAX UINT64_MAX
#else
# define WORK_DELAY_MAX UINT32_MAX
#endif
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/* The state of the user mode work queue. */
struct usr_wqueue_s g_usrwork;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: work_process
*
* Description:
* This is the logic that performs actions placed on any work list. This
* logic is the common underlying logic to all work queues. This logic is
* part of the internal implementation of each work queue; it should not
* be called from application level logic.
*
* Input Parameters:
* wqueue - Describes the work queue to be processed
*
* Returned Value:
* None
*
****************************************************************************/
static void work_process(FAR struct usr_wqueue_s *wqueue)
{
volatile FAR struct work_s *work;
worker_t worker;
FAR void *arg;
sclock_t elapsed;
clock_t next;
int ret;
/* Then process queued work. Lock the work queue while we process items
* in the work list.
*/
next = WORK_DELAY_MAX;
ret = _SEM_WAIT(&wqueue->lock);
if (ret < 0)
{
/* Break out earlier if we were awakened by a signal */
return;
}
/* And check each entry in the work queue. Since we have locked the
* work queue we know: (1) we will not be suspended unless we do
* so ourselves, and (2) there will be no changes to the work queue
*/
work = (FAR struct work_s *)wqueue->q.head;
while (work)
{
/* Is this work ready? It is ready if there is no delay or if
* the delay has elapsed. is the time that the work was added
* to the work queue. Therefore a delay of equal or less than
* zero will always execute immediately.
*/
elapsed = clock() - work->u.s.qtime;
/* Is this delay work ready? */
if (elapsed >= 0)
{
/* Remove the ready-to-execute work from the list */
sq_remfirst(&wqueue->q);
/* Extract the work description from the entry (in case the work
* instance by the re-used after it has been de-queued).
*/
worker = work->worker;
/* Check for a race condition where the work may be nullified
* before it is removed from the queue.
*/
if (worker != NULL)
{
/* Extract the work argument before unlocking the work queue */
arg = work->arg;
/* Mark the work as no longer being queued */
work->worker = NULL;
/* Do the work. Unlock the work queue while the work is being
* performed... we don't have any idea how long this will take!
*/
_SEM_POST(&wqueue->lock);
worker(arg);
/* Now, unfortunately, since we unlocked the work queue we
* don't know the state of the work list and we will have to
* start back at the head of the list.
*/
ret = _SEM_WAIT(&wqueue->lock);
if (ret < 0)
{
/* Break out earlier if we were awakened by a signal */
return;
}
}
work = (FAR struct work_s *)wqueue->q.head;
}
else
{
next = work->u.s.qtime - clock();
break;
}
}
/* Unlock the work queue before waiting. */
_SEM_POST(&wqueue->lock);
if (next == WORK_DELAY_MAX)
{
/* Wait indefinitely until work_queue has new items */
_SEM_WAIT(&wqueue->wake);
}
else
{
struct timespec now;
struct timespec delay;
struct timespec rqtp;
/* Wait awhile to check the work list. We will wait here until
* either the time elapses or until we are awakened by a semaphore.
* Interrupts will be re-enabled while we wait.
*/
clock_gettime(CLOCK_REALTIME, &now);
clock_ticks2time(next, &delay);
clock_timespec_add(&now, &delay, &rqtp);
_SEM_TIMEDWAIT(&wqueue->wake, &rqtp);
}
}
/****************************************************************************
* Name: work_usrthread
*
* Description:
* This is the worker thread that performs the actions placed on the user
* work queue.
*
* This is a user mode work queue. It must be used by applications for
* miscellaneous operations. The user work thread must be started by
* application start-up logic by calling work_usrstart().
*
* Input Parameters:
* argc, argv (not used)
*
* Returned Value:
* Does not return
*
****************************************************************************/
#ifdef CONFIG_BUILD_PROTECTED
static int work_usrthread(int argc, char *argv[])
#else
static pthread_addr_t work_usrthread(pthread_addr_t arg)
#endif
{
/* Loop forever */
for (; ; )
{
/* Then process queued work. We need to keep the work queue locked
* while we process items in the work list.
*/
work_process(&g_usrwork);
}
#ifdef CONFIG_BUILD_PROTECTED
return OK; /* To keep some compilers happy */
#else
return NULL; /* To keep some compilers happy */
#endif
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: work_usrstart
*
* Description:
* Start the user mode work queue.
*
* Input Parameters:
* None
*
* Returned Value:
* The task ID of the worker thread is returned on success. A negated
* errno value is returned on failure.
*
****************************************************************************/
int work_usrstart(void)
{
int ret;
#ifndef CONFIG_BUILD_PROTECTED
pthread_t usrwork;
pthread_attr_t attr;
struct sched_param param;
#endif
/* Set up the work queue lock */
_SEM_INIT(&g_usrwork.lock, 0, 1);
_SEM_INIT(&g_usrwork.wake, 0, 0);
_SEM_SETPROTOCOL(&g_usrwork.wake, SEM_PRIO_NONE);
/* Initialize the work queue */
sq_init(&g_usrwork.q);
#ifdef CONFIG_BUILD_PROTECTED
/* Start a user-mode worker thread for use by applications. */
ret = task_create("uwork",
CONFIG_LIBC_USRWORKPRIORITY,
CONFIG_LIBC_USRWORKSTACKSIZE,
(main_t)work_usrthread,
((FAR char * const *)NULL));
if (ret < 0)
{
int errcode = get_errno();
DEBUGASSERT(errcode > 0);
return -errcode;
}
return ret;
#else
/* Start a user-mode worker thread for use by applications. */
pthread_attr_init(&attr);
pthread_attr_setstacksize(&attr, CONFIG_LIBC_USRWORKSTACKSIZE);
pthread_attr_getschedparam(&attr, &param);
param.sched_priority = CONFIG_LIBC_USRWORKPRIORITY;
pthread_attr_setschedparam(&attr, &param);
ret = pthread_create(&usrwork, &attr, work_usrthread, NULL);
if (ret != 0)
{
return -ret;
}
/* Detach because the return value and completion status will not be
* requested.
*/
pthread_detach(usrwork);
return (pid_t)usrwork;
#endif
}
#endif /* CONFIG_LIBC_USRWORK && !__KERNEL__*/