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- /****************************************************************************
- * wireless/pktradio/pktradio_metadata.c
- *
- * Copyright (C) 2017 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 <stdbool.h>
- #include <string.h>
- #include <semaphore.h>
- #include <assert.h>
- #include <errno.h>
- #include <nuttx/kmalloc.h>
- #include <nuttx/mm/iob.h>
- #include <nuttx/wireless/pktradio.h>
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- /* The g_free_metadata is a list of meta-data structures that are available for
- * general use. The number of messages in this list is a system configuration
- * item.
- */
- static FAR struct pktradio_metadata_s *g_free_metadata;
- /* Supports mutually exclusive access to the free list */
- static sem_t g_metadata_sem;
- /* Idempotence support */
- static bool g_metadata_initialized;
- /* Pool of pre-allocated meta-data stuctures */
- static struct pktradio_metadata_s g_metadata_pool[CONFIG_PKTRADIO_NRXMETA];
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: pktradio_metadata_initialize
- *
- * Description:
- * This function initializes the meta-data allocator. This function must
- * be called early in the initialization sequence before any radios
- * begin operation.
- *
- * Inputs:
- * None
- *
- * Return Value:
- * None
- *
- ****************************************************************************/
- void pktradio_metadata_initialize(void)
- {
- FAR struct pktradio_metadata_s *metadata;
- int i;
- if (!g_metadata_initialized)
- {
- /* Initialize g_free_metadata, the list of meta-data structures that
- * are available for allocation.
- */
- g_free_metadata = NULL;
- for (i = 0, metadata = g_metadata_pool;
- i < CONFIG_PKTRADIO_NRXMETA;
- i++, metadata++)
- {
- /* Add the next meta data structure from the pool to the list of
- * general structures.
- */
- metadata->pm_flink = g_free_metadata;
- g_free_metadata = metadata;
- }
- /* Initialize the mutual exclusion semaphore */
- sem_init(&g_metadata_sem, 0, 1);
- g_metadata_initialized = true;
- }
- }
- /****************************************************************************
- * Name: pktradio_metadata_allocate
- *
- * Description:
- * The pktradio_metadata_allocate function will get a free meta-data
- * structure for use by the packet radio.
- *
- * This function will first attempt to allocate from the g_free_metadata
- * list. If that the list is empty, then the meta-data structure will be
- * allocated from the dynamic memory pool.
- *
- * Inputs:
- * None
- *
- * Return Value:
- * A reference to the allocated metadata structure. All user fields in this
- * structure have been zeroed. On a failure to allocate, NULL is
- * returned.
- *
- ****************************************************************************/
- FAR struct pktradio_metadata_s *pktradio_metadata_allocate(void)
- {
- FAR struct pktradio_metadata_s *metadata;
- uint8_t pool;
- /* Get exclusive access to the free list */
- while (sem_wait(&g_metadata_sem) < 0)
- {
- DEBUGASSERT(errno == EINTR);
- }
- /* Try the free list first */
- if (g_free_metadata != NULL)
- {
- metadata = g_free_metadata;
- g_free_metadata = metadata->pm_flink;
- pool = PKTRADIO_POOL_PREALLOCATED;
- /* We are finished with the free list */
- sem_post(&g_metadata_sem);
- }
- else
- {
- /* If we cannot get a meta-data instance from the free list, then we
- * will have to allocate one from the kernal memory pool. We won't
- * access the free list.
- */
- sem_post(&g_metadata_sem);
- metadata = (FAR struct pktradio_metadata_s *)
- kmm_malloc((sizeof (struct pktradio_metadata_s)));
- pool = PKTRADIO_POOL_DYNAMIC;
- }
- /* We have successfully allocated memory from some source? */
- if (metadata != NULL)
- {
- /* Zero and tag the allocated meta-data structure. */
- memset(metadata, 0, sizeof(struct pktradio_metadata_s));
- metadata->pm_pool = pool;
- }
- return metadata;
- }
- /****************************************************************************
- * Name: pktradio_metadata_free
- *
- * Description:
- * The pktradio_metadata_free function will return a metadata structure
- * to the free list of messages if it was a pre-allocated metadata
- * structure. If the metadata structure was allocated dynamically it will
- * be deallocated.
- *
- * Inputs:
- * metadata - metadata structure to free
- *
- * Return Value:
- * None
- *
- ****************************************************************************/
- void pktradio_metadata_free(FAR struct pktradio_metadata_s *metadata)
- {
- /* Get exclusive access to the free list */
- while (sem_wait(&g_metadata_sem) < 0)
- {
- DEBUGASSERT(errno == EINTR);
- }
- /* If this is a pre-allocated meta-data structure, then just put it back
- * in the free list.
- */
- if (metadata->pm_pool == PKTRADIO_POOL_PREALLOCATED)
- {
- metadata->pm_flink = g_free_metadata;
- g_free_metadata = metadata;
- /* We are finished with the free list */
- sem_post(&g_metadata_sem);
- }
- else
- {
- DEBUGASSERT(metadata->pm_pool == PKTRADIO_POOL_DYNAMIC);
- /* Otherwise, deallocate it. We won't access the free list */
- sem_post(&g_metadata_sem);
- sched_kfree(metadata);
- }
- }
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