incubator-nuttx/mm/iob/iob_initialize.c

135 lines
4.0 KiB
C

/****************************************************************************
* mm/iob/iob_initialize.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 <stdbool.h>
#include <nuttx/mm/iob.h>
#include "iob.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef NULL
# define NULL ((FAR void *)0)
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/* This is a pool of pre-allocated I/O buffers */
static struct iob_s g_iob_pool[CONFIG_IOB_NBUFFERS];
#if CONFIG_IOB_NCHAINS > 0
static struct iob_qentry_s g_iob_qpool[CONFIG_IOB_NCHAINS];
#endif
/****************************************************************************
* Public Data
****************************************************************************/
/* A list of all free, unallocated I/O buffers */
FAR struct iob_s *g_iob_freelist;
/* A list of I/O buffers that are committed for allocation */
FAR struct iob_s *g_iob_committed;
#if CONFIG_IOB_NCHAINS > 0
/* A list of all free, unallocated I/O buffer queue containers */
FAR struct iob_qentry_s *g_iob_freeqlist;
/* A list of I/O buffer queue containers that are committed for allocation */
FAR struct iob_qentry_s *g_iob_qcommitted;
#endif
/* Counting semaphores that tracks the number of free IOBs/qentries */
sem_t g_iob_sem = SEM_INITIALIZER(CONFIG_IOB_NBUFFERS);
#if CONFIG_IOB_THROTTLE > 0
/* Counts available I/O buffers when throttled */
sem_t g_throttle_sem = SEM_INITIALIZER(CONFIG_IOB_NBUFFERS -
CONFIG_IOB_THROTTLE);
#endif
#if CONFIG_IOB_NCHAINS > 0
/* Counts free I/O buffer queue containers */
sem_t g_qentry_sem = SEM_INITIALIZER(CONFIG_IOB_NCHAINS);
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: iob_initialize
*
* Description:
* Set up the I/O buffers for normal operations.
*
****************************************************************************/
void iob_initialize(void)
{
int i;
/* Add each I/O buffer to the free list */
for (i = 0; i < CONFIG_IOB_NBUFFERS; i++)
{
FAR struct iob_s *iob = &g_iob_pool[i];
/* Add the pre-allocate I/O buffer to the head of the free list */
iob->io_flink = g_iob_freelist;
g_iob_freelist = iob;
}
#if CONFIG_IOB_NCHAINS > 0
/* Add each I/O buffer chain queue container to the free list */
for (i = 0; i < CONFIG_IOB_NCHAINS; i++)
{
FAR struct iob_qentry_s *iobq = &g_iob_qpool[i];
/* Add the pre-allocate buffer container to the head of the free
* list
*/
iobq->qe_flink = g_iob_freeqlist;
g_iob_freeqlist = iobq;
}
#endif
}