incubator-nuttx/net/can/can_conn.c

240 lines
6.6 KiB
C

/****************************************************************************
* net/can/can_conn.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 <string.h>
#include <queue.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/kmalloc.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/net.h>
#include "utils/utils.h"
#include "can/can.h"
#ifdef CONFIG_NET_CAN
/****************************************************************************
* Private Data
****************************************************************************/
/* The array containing all NetLink connections. */
#ifndef CONFIG_NET_ALLOC_CONNS
static struct can_conn_s g_can_connections[CONFIG_CAN_CONNS];
#endif
/* A list of all free NetLink connections */
static dq_queue_t g_free_can_connections;
static sem_t g_free_sem;
/* A list of all allocated NetLink connections */
static dq_queue_t g_active_can_connections;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: _can_semtake() and _can_semgive()
*
* Description:
* Take/give semaphore
*
****************************************************************************/
static void _can_semtake(FAR sem_t *sem)
{
net_lockedwait_uninterruptible(sem);
}
static void _can_semgive(FAR sem_t *sem)
{
nxsem_post(sem);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: can_initialize()
*
* Description:
* Initialize the User Socket connection structures. Called once and only
* from the networking layer.
*
****************************************************************************/
void can_initialize(void)
{
#ifndef CONFIG_NET_ALLOC_CONNS
int i;
#endif
/* Initialize the queues */
dq_init(&g_free_can_connections);
dq_init(&g_active_can_connections);
nxsem_init(&g_free_sem, 0, 1);
#ifndef CONFIG_NET_ALLOC_CONNS
for (i = 0; i < CONFIG_CAN_CONNS; i++)
{
/* Mark the connection closed and move it to the free list */
dq_addlast(&g_can_connections[i].sconn.node, &g_free_can_connections);
}
#endif
}
/****************************************************************************
* Name: can_alloc()
*
* Description:
* Allocate a new, uninitialized NetLink connection structure. This is
* normally something done by the implementation of the socket() API
*
****************************************************************************/
FAR struct can_conn_s *can_alloc(void)
{
FAR struct can_conn_s *conn;
#ifdef CONFIG_NET_ALLOC_CONNS
int i;
#endif
/* The free list is protected by a semaphore (that behaves like a mutex). */
_can_semtake(&g_free_sem);
#ifdef CONFIG_NET_ALLOC_CONNS
if (dq_peek(&g_free_can_connections) == NULL)
{
conn = kmm_zalloc(sizeof(*conn) * CONFIG_CAN_CONNS);
if (conn != NULL)
{
for (i = 0; i < CONFIG_CAN_CONNS; i++)
{
dq_addlast(&conn[i].sconn.node, &g_free_can_connections);
}
}
}
#endif
conn = (FAR struct can_conn_s *)dq_remfirst(&g_free_can_connections);
if (conn != NULL)
{
/* FIXME SocketCAN default behavior enables loopback */
#ifdef CONFIG_NET_CANPROTO_OPTIONS
/* By default the filter is configured to catch all,
* this is done in commented filter code below:
*
* struct can_filter_t catchall_filter;
* filter.can_id = 0;
* filter.can_mask = 0;
* conn->filters[0] = catchall_filter;
*
* However memset already sets the filter to 0
* therefore we only have to set the filter count to 1
*/
conn->filter_count = 1;
#endif
/* Enqueue the connection into the active list */
dq_addlast(&conn->sconn.node, &g_active_can_connections);
}
_can_semgive(&g_free_sem);
return conn;
}
/****************************************************************************
* Name: can_free()
*
* Description:
* Free a NetLink connection structure that is no longer in use. This
* should be done by the implementation of close().
*
****************************************************************************/
void can_free(FAR struct can_conn_s *conn)
{
/* The free list is protected by a semaphore (that behaves like a mutex). */
DEBUGASSERT(conn->crefs == 0);
_can_semtake(&g_free_sem);
/* Remove the connection from the active list */
dq_rem(&conn->sconn.node, &g_active_can_connections);
/* Reset structure */
memset(conn, 0, sizeof(*conn));
/* Free the connection */
dq_addlast(&conn->sconn.node, &g_free_can_connections);
_can_semgive(&g_free_sem);
}
/****************************************************************************
* Name: can_nextconn()
*
* Description:
* Traverse the list of allocated NetLink connections
*
* Assumptions:
* This function is called from NetLink device logic.
*
****************************************************************************/
FAR struct can_conn_s *can_nextconn(FAR struct can_conn_s *conn)
{
if (conn == NULL)
{
return (FAR struct can_conn_s *)g_active_can_connections.head;
}
else
{
return (FAR struct can_conn_s *)conn->sconn.node.flink;
}
}
#endif /* CONFIG_NET_CAN */