incubator-nuttx/net/can/can_callback.c

242 lines
7.3 KiB
C

/****************************************************************************
* net/can/can_callback.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>
#if defined(CONFIG_NET) && defined(CONFIG_NET_CAN)
#include <stdint.h>
#include <debug.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/mm/iob.h>
#include "devif/devif.h"
#include "can/can.h"
#ifdef CONFIG_NET_TIMESTAMP
#include <sys/time.h>
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: can_data_event
*
* Description:
* Handle data that is not accepted by the application because there is no
* listener in place ready to receive the data.
*
* Assumptions:
* - The caller has checked that CAN_NEWDATA is set in flags and that is no
* other handler available to process the incoming data.
* - This function must be called with the network locked.
*
****************************************************************************/
static inline uint16_t
can_data_event(FAR struct net_driver_s *dev, FAR struct can_conn_s *conn,
uint16_t flags)
{
uint16_t ret;
FAR uint8_t *buffer = dev->d_appdata;
int buflen = dev->d_len;
uint16_t recvlen;
ret = (flags & ~CAN_NEWDATA);
/* Save as the packet data as in the read-ahead buffer. NOTE that
* partial packets will not be buffered.
*/
recvlen = can_datahandler(conn, buffer, buflen);
if (recvlen < buflen)
{
/* There is no handler to receive new data and there are no free
* read-ahead buffers to retain the data -- drop the packet.
*/
ninfo("Dropped %d bytes\n", dev->d_len);
#ifdef CONFIG_NET_STATISTICS
/* No support CAN net statistics yet */
/* g_netstats.tcp.drop++; */
#endif
}
/* In any event, the new data has now been handled */
dev->d_len = 0;
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: can_callback
*
* Description:
* Inform the application holding the packet socket of a change in state.
*
* Returned Value:
* OK if packet has been processed, otherwise ERROR.
*
* Assumptions:
* This function can be called from an interrupt.
*
****************************************************************************/
uint16_t can_callback(FAR struct net_driver_s *dev,
FAR struct can_conn_s *conn, uint16_t flags)
{
/* Some sanity checking */
if (conn)
{
#ifdef CONFIG_NET_TIMESTAMP
/* TIMESTAMP sockopt is activated, create timestamp and copy to iob */
if (conn->sconn.s_timestamp)
{
struct timespec *ts = (struct timespec *)
&dev->d_appdata[dev->d_len];
struct timeval *tv = (struct timeval *)
&dev->d_appdata[dev->d_len];
dev->d_len += sizeof(struct timeval);
clock_systime_timespec(ts);
tv->tv_usec = ts->tv_nsec / 1000;
}
#endif
/* Try to lock the network when successful send data to the listener */
if (net_trylock() == OK)
{
flags = devif_conn_event(dev, flags, conn->sconn.list);
net_unlock();
}
/* Either we did not get the lock or there is no application listening
* If we did not get a lock we store the frame in the read-ahead buffer
*/
if ((flags & CAN_NEWDATA) != 0)
{
/* Data was not handled.. dispose of it appropriately */
flags = can_data_event(dev, conn, flags);
}
}
return flags;
}
/****************************************************************************
* Name: can_datahandler
*
* Description:
* Handle data that is not accepted by the application. This may be called
* either (1) from the data receive logic if it cannot buffer the data, or
* (2) from the CAN event logic is there is no listener in place ready to
* receive the data.
*
* Input Parameters:
* conn - A pointer to the CAN connection structure
* buffer - A pointer to the buffer to be copied to the read-ahead
* buffers
* buflen - The number of bytes to copy to the read-ahead buffer.
*
* Returned Value:
* The number of bytes actually buffered is returned. This will be either
* zero or equal to buflen; partial packets are not buffered.
*
* Assumptions:
* - The caller has checked that CAN_NEWDATA is set in flags and that is no
* other handler available to process the incoming data.
* - This function must be called with the network locked.
*
****************************************************************************/
uint16_t can_datahandler(FAR struct can_conn_s *conn, FAR uint8_t *buffer,
uint16_t buflen)
{
FAR struct iob_s *iob;
int ret;
/* Try to allocate on I/O buffer to start the chain without waiting (and
* throttling as necessary). If we would have to wait, then drop the
* packet.
*/
iob = iob_tryalloc(true);
if (iob == NULL)
{
nerr("ERROR: Failed to create new I/O buffer chain\n");
return 0;
}
/* Copy the new appdata into the I/O buffer chain (without waiting) */
ret = iob_trycopyin(iob, buffer, buflen, 0, true);
if (ret < 0)
{
/* On a failure, iob_copyin return a negated error value but does
* not free any I/O buffers.
*/
nerr("ERROR: Failed to add data to the I/O buffer chain: %d\n", ret);
iob_free_chain(iob);
return 0;
}
/* Add the new I/O buffer chain to the tail of the read-ahead queue (again
* without waiting).
*/
ret = iob_tryadd_queue(iob, &conn->readahead);
if (ret < 0)
{
nerr("ERROR: Failed to queue the I/O buffer chain: %d\n", ret);
iob_free_chain(iob);
return 0;
}
#ifdef CONFIG_NET_CAN_NOTIFIER
/* Provide notification(s) that additional CAN read-ahead data is
* available.
*/
can_readahead_signal(conn);
#endif
return buflen;
}
#endif /* CONFIG_NET && CONFIG_NET_CAN */