/****************************************************************************
* libc/wqueue/work_thread.c
*
* Copyright (C) 2009-2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <unistd.h>
#include <queue.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include <nuttx/clock.h>
#include <nuttx/kmalloc.h>
#ifdef CONFIG_SCHED_WORKQUEUE
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/* The state of each work queue. */
#ifdef CONFIG_NUTTX_KERNEL
/* Play some games in the kernel mode build to assure that different
* naming is used for the global work queue data structures. This may
* not be necessary but it safer.
*
* In this case g_work is #define'd to be either g_kernelwork or
* g_usrwork in include/nuttx/wqueue.h
*/
# ifdef __KERNEL__
struct wqueue_s g_kernelwork[NWORKERS];
# else
struct wqueue_s g_usrwork[NWORKERS];
# endif
#else /* CONFIG_NUTTX_KERNEL */
struct wqueue_s g_work[NWORKERS];
#endif /* CONFIG_NUTTX_KERNEL */
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: work_process
*
* Description:
* This is the logic that performs actions placed on any work list.
*
* Input parameters:
* wqueue - Describes the work queue to be processed
*
* Returned Value:
* None
*
****************************************************************************/
static void work_process(FAR struct wqueue_s *wqueue)
{
volatile FAR struct work_s *work;
worker_t worker;
irqstate_t flags;
FAR void *arg;
uint32_t elapsed;
uint32_t remaining;
uint32_t next;
/* Then process queued work. We need to keep interrupts disabled while
* we process items in the work list.
*/
next = CONFIG_SCHED_WORKPERIOD / USEC_PER_TICK;
flags = irqsave();
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. qtime is the time that the work was added
* to the work queue. It will always be greater than or equal to
* zero. Therefore a delay of zero will always execute immediately.
*/
elapsed = clock_systimer() - work->qtime;
if (elapsed >= work->delay)
{
/* Remove the ready-to-execute work from the list */
(void)dq_rem((struct dq_entry_s *)work, &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;
arg = work->arg;
/* Mark the work as no longer being queued */
work->worker = NULL;
/* Do the work. Re-enable interrupts while the work is being
* performed... we don't have any idea how long that will take!
*/
irqrestore(flags);
worker(arg);
/* Now, unfortunately, since we re-enabled interrupts we don't
* know the state of the work list and we will have to start
* back at the head of the list.
*/
flags = irqsave();
work = (FAR struct work_s *)wqueue->q.head;
}
else
{
/* This one is not ready.. will it be ready before the next
* scheduled wakeup interval?
*/
/* Here: elapsed < work->delay */
remaining = work->delay - elapsed;
if (remaining < next)
{
/* Yes.. Then schedule to wake up when the work is ready */
next = remaining;
}
/* Then try the next in the list. */
work = (FAR struct work_s *)work->dq.flink;
}
}
/* Wait awhile to check the work list. We will wait here until either
* the time elapses or until we are awakened by a signal.
*/
usleep(next * USEC_PER_TICK);
irqrestore(flags);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: work_hpthread, work_lpthread, and work_usrthread
*
* Description:
* These are the worker threads that performs actions placed on the work
* lists.
*
* work_hpthread and work_lpthread: These are the kernel mode work queues
* (also build in the flat build). One of these threads also performs
* periodic garbage collection (that is otherwise performed by the idle
* thread if CONFIG_SCHED_WORKQUEUE is not defined).
*
* These worker threads are started by the OS during normal bringup.
*
* work_usrthread: This is a user mode work queue. It must be built into
* the applicatino blob during the user phase of a kernel build. The
* user work thread will then automatically be started when the system
* boots by calling through the pointer found in the header on the user
* space blob.
*
* All of these entrypoints are referenced by OS internally and should not
* not be accessed by application logic.
*
* Input parameters:
* argc, argv (not used)
*
* Returned Value:
* Does not return
*
****************************************************************************/
#ifdef CONFIG_SCHED_HPWORK
int work_hpthread(int argc, char *argv[])
{
/* Loop forever */
for (;;)
{
/* First, perform garbage collection. This cleans-up memory de-allocations
* that were queued because they could not be freed in that execution
* context (for example, if the memory was freed from an interrupt handler).
* NOTE: If the work thread is disabled, this clean-up is performed by
* the IDLE thread (at a very, very low priority).
*/
#ifndef CONFIG_SCHED_LPWORK
sched_garbagecollection();
#endif
/* Then process queued work. We need to keep interrupts disabled while
* we process items in the work list.
*/
work_process(&g_work[HPWORK]);
}
return OK; /* To keep some compilers happy */
}
#ifdef CONFIG_SCHED_LPWORK
int work_lpthread(int argc, char *argv[])
{
/* Loop forever */
for (;;)
{
/* First, perform garbage collection. This cleans-up memory de-allocations
* that were queued because they could not be freed in that execution
* context (for example, if the memory was freed from an interrupt handler).
* NOTE: If the work thread is disabled, this clean-up is performed by
* the IDLE thread (at a very, very low priority).
*/
sched_garbagecollection();
/* Then process queued work. We need to keep interrupts disabled while
* we process items in the work list.
*/
work_process(&g_work[LPWORK]);
}
return OK; /* To keep some compilers happy */
}
#endif /* CONFIG_SCHED_LPWORK */
#endif /* CONFIG_SCHED_HPWORK */
#ifdef CONFIG_SCHED_USRWORK
int work_usrthread(int argc, char *argv[])
{
/* Loop forever */
for (;;)
{
/* Then process queued work. We need to keep interrupts disabled while
* we process items in the work list.
*/
work_process(&g_work[USRWORK]);
}
return OK; /* To keep some compilers happy */
}
#endif /* CONFIG_SCHED_USRWORK */
#endif /* CONFIG_SCHED_WORKQUEUE */
