83cdb0c552
libc/semaphore: Add nxsem_getvalue() which is identical to sem_getvalue() except that it never modifies the errno variable. Changed all references to sem_getvalue in the OS to nxsem_getvalue().
sched/semaphore: Rename all internal private functions from sem_xyz to nxsem_xyz. The sem_ prefix is (will be) reserved only for the application semaphore interfaces.
libc/semaphore: Add nxsem_init() which is identical to sem_init() except that it never modifies the errno variable. Changed all references to sem_init in the OS to nxsem_init().
sched/semaphore: Rename sem_tickwait() to nxsem_tickwait() so that it is clear this is an internal OS function.
sched/semaphoate: Rename sem_reset() to nxsem_reset() so that it is clear this is an internal OS function.
424 lines
12 KiB
C
424 lines
12 KiB
C
/****************************************************************************
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* libc/wqueue/work_usrthread.c
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*
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* Copyright (C) 2009-2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <sched.h>
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#include <errno.h>
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#include <assert.h>
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#include <queue.h>
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#include <nuttx/wqueue.h>
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#include <nuttx/clock.h>
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#include "wqueue/wqueue.h"
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#if defined(CONFIG_LIB_USRWORK) && !defined(__KERNEL__)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Use CLOCK_MONOTONIC if it is available. CLOCK_REALTIME can cause bad
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* delays if the time is changed.
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*/
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#ifdef CONFIG_CLOCK_MONOTONIC
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# define WORK_CLOCK CLOCK_MONOTONIC
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#else
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# define WORK_CLOCK CLOCK_REALTIME
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#endif
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#ifndef MIN
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# define MIN(a,b) ((a) < (b) ? (a) : (b))
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#endif
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/****************************************************************************
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* Private Type Declarations
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****************************************************************************/
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/* The state of the user mode work queue. */
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struct usr_wqueue_s g_usrwork;
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/* This semaphore supports exclusive access to the user-mode work queue */
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#ifdef CONFIG_BUILD_PROTECTED
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sem_t g_usrsem;
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#else
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pthread_mutex_t g_usrmutex;
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#endif
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: work_process
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*
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* Description:
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* This is the logic that performs actions placed on any work list. This
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* logic is the common underlying logic to all work queues. This logic is
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* part of the internal implementation of each work queue; it should not
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* be called from application level logic.
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*
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* Input parameters:
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* wqueue - Describes the work queue to be processed
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void work_process(FAR struct usr_wqueue_s *wqueue)
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{
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volatile FAR struct work_s *work;
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worker_t worker;
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FAR void *arg;
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systime_t elapsed;
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systime_t remaining;
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systime_t stick;
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systime_t ctick;
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systime_t next;
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int ret;
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/* Then process queued work. Lock the work queue while we process items
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* in the work list.
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*/
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next = wqueue->delay;
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ret = work_lock();
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if (ret < 0)
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{
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/* Break out earlier if we were awakened by a signal */
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return;
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}
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/* Get the time that we started this polling cycle in clock ticks. */
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stick = clock_systimer();
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/* And check each entry in the work queue. Since we have locked the
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* work queue we know: (1) we will not be suspended unless we do
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* so ourselves, and (2) there will be no changes to the work queue
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*/
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work = (FAR struct work_s *)wqueue->q.head;
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while (work)
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{
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/* Is this work ready? It is ready if there is no delay or if
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* the delay has elapsed. qtime is the time that the work was added
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* to the work queue. It will always be greater than or equal to
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* zero. Therefore a delay of zero will always execute immediately.
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*/
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ctick = clock_systimer();
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elapsed = ctick - work->qtime;
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if (elapsed >= work->delay)
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{
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/* Remove the ready-to-execute work from the list */
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(void)dq_rem((struct dq_entry_s *)work, &wqueue->q);
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/* Extract the work description from the entry (in case the work
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* instance by the re-used after it has been de-queued).
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*/
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worker = work->worker;
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/* Check for a race condition where the work may be nullified
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* before it is removed from the queue.
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*/
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if (worker != NULL)
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{
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/* Extract the work argument (before unlocking the work queue) */
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arg = work->arg;
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/* Mark the work as no longer being queued */
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work->worker = NULL;
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/* Do the work. Unlock the work queue while the work is being
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* performed... we don't have any idea how long this will take!
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*/
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work_unlock();
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worker(arg);
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/* Now, unfortunately, since we unlocked the work queue we don't
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* know the state of the work list and we will have to start
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* back at the head of the list.
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*/
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ret = work_lock();
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if (ret < 0)
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{
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/* Break out earlier if we were awakened by a signal */
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return;
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}
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work = (FAR struct work_s *)wqueue->q.head;
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}
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else
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{
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/* Cancelled.. Just move to the next work in the list with
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* the work queue still locked.
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*/
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work = (FAR struct work_s *)work->dq.flink;
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}
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}
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else /* elapsed < work->delay */
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{
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/* This one is not ready.
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*
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* NOTE that elapsed is relative to the current time,
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* not the time of beginning of this queue processing pass.
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* So it may need an adjustment.
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*/
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elapsed += (ctick - stick);
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if (elapsed > work->delay)
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{
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/* The delay has expired while we are processing */
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elapsed = work->delay;
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}
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/* Will it be ready before the next scheduled wakeup interval? */
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remaining = work->delay - elapsed;
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if (remaining < next)
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{
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/* Yes.. Then schedule to wake up when the work is ready */
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next = remaining;
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}
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/* Then try the next in the list. */
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work = (FAR struct work_s *)work->dq.flink;
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}
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}
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/* Get the delay (in clock ticks) since we started the sampling */
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elapsed = clock_systimer() - stick;
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if (elapsed < wqueue->delay && next > 0)
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{
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/* How must time would we need to delay to get to the end of the
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* sampling period? The amount of time we delay should be the smaller
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* of the time to the end of the sampling period and the time to the
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* next work expiry.
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*/
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remaining = wqueue->delay - elapsed;
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next = MIN(next, remaining);
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/* Wait awhile to check the work list. We will wait here until
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* either the time elapses or until we are awakened by a signal.
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* Interrupts will be re-enabled while we wait.
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*/
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usleep(next * USEC_PER_TICK);
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}
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work_unlock();
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}
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/****************************************************************************
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* Name: work_usrthread
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*
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* Description:
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* This is the worker thread that performs the actions placed on the user
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* work queue.
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*
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* This is a user mode work queue. It must be used by applications for
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* miscellaneous operations. The user work thread must be started by
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* application start-up logic by calling work_usrstart().
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*
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* Input parameters:
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* argc, argv (not used)
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*
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* Returned Value:
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* Does not return
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*
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****************************************************************************/
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#ifdef CONFIG_BUILD_PROTECTED
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static int work_usrthread(int argc, char *argv[])
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#else
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static pthread_addr_t work_usrthread(pthread_addr_t arg)
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#endif
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{
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/* Loop forever */
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for (; ; )
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{
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/* Then process queued work. We need to keep the work queue locked
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* while we process items in the work list.
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*/
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work_process(&g_usrwork);
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}
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#ifdef CONFIG_BUILD_PROTECTED
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return OK; /* To keep some compilers happy */
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#else
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return NULL; /* To keep some compilers happy */
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#endif
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: work_usrstart
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*
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* Description:
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* Start the user mode work queue.
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*
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* Input parameters:
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* None
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*
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* Returned Value:
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* The task ID of the worker thread is returned on success. A negated
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* errno value is returned on failure.
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*
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****************************************************************************/
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int work_usrstart(void)
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{
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/* Initialize work queue data structures */
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g_usrwork.delay = CONFIG_LIB_USRWORKPERIOD / USEC_PER_TICK;
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dq_init(&g_usrwork.q);
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#ifdef CONFIG_BUILD_PROTECTED
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{
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/* Set up the work queue lock */
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(void)nxsem_init(&g_usrsem, 0, 1);
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/* Start a user-mode worker thread for use by applications. */
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g_usrwork.pid = task_create("uwork",
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CONFIG_LIB_USRWORKPRIORITY,
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CONFIG_LIB_USRWORKSTACKSIZE,
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(main_t)work_usrthread,
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(FAR char * const *)NULL);
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DEBUGASSERT(g_usrwork.pid > 0);
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if (g_usrwork.pid < 0)
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{
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int errcode = errno;
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DEBUGASSERT(errcode > 0);
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return -errcode;
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}
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return g_usrwork.pid;
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}
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#else
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{
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pthread_t usrwork;
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pthread_attr_t attr;
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struct sched_param param;
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int ret;
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/* Set up the work queue lock */
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(void)pthread_mutex_init(&g_usrmutex, NULL);
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/* Start a user-mode worker thread for use by applications. */
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(void)pthread_attr_init(&attr);
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(void)pthread_attr_setstacksize(&attr, CONFIG_LIB_USRWORKSTACKSIZE);
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#ifdef CONFIG_SCHED_SPORADIC
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/* Get the current sporadic scheduling parameters. Those will not be
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* modified.
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*/
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ret = set_getparam(pid, ¶m);
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if (ret < 0)
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{
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int erroode = get_errno();
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return -errcode;
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}
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#endif
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param.sched_priority = CONFIG_LIB_USRWORKPRIORITY;
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(void)pthread_attr_setschedparam(&attr, ¶m);
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ret = pthread_create(&usrwork, &attr, work_usrthread, NULL);
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if (ret != 0)
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{
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return -ret;
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}
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/* Detach because the return value and completion status will not be
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* requested.
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*/
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(void)pthread_detach(usrwork);
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g_usrwork.pid = (pid_t)usrwork;
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return g_usrwork.pid;
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}
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#endif
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}
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#endif /* CONFIG_LIB_USRWORK && !__KERNEL__*/
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