incubator-nuttx/include/nuttx/ipcc.h

209 lines
7.2 KiB
C

/****************************************************************************
* include/nuttx/ipcc.h
*
* 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.
*
****************************************************************************/
#ifndef __INCLUDE_NUTTX_IPCC_H
#define __INCLUDE_NUTTX_IPCC_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/mm/circbuf.h>
#include <nuttx/semaphore.h>
#include <poll.h>
/****************************************************************************
* Public Types
****************************************************************************/
/* IPCC is a two-part driver:
*
* 1) A common upper half driver, that provides the character device
* interface for the user
* 2) Platform-specific lower half drivers that provide interface
* between upper and lower layer. Lower half also contains
* common objects like semaphore to inform
*/
/* This structure defines all of the operations provided by the
* architecture specific logic. All fields must be provided with
* non-NULL function pointers.
*/
struct ipcc_lower_s;
struct ipcc_ops_s
{
/**************************************************************************
* Name: read
*
* Description:
* Reads data directly from IPCC mbox, function shall not block.
* If no data is available, 0 shall be returned. Partial read
* is possible. In that case function can return value less
* than buflen.
*
* Input Parameters:
* ipcc - ipcc channel to read data from
* buffer - location where data shall be stored
* buflen - size of the buffer
*
* Returned Value:
* Number of bytes actually written to buffer.
*
**************************************************************************/
CODE ssize_t (*read)(FAR struct ipcc_lower_s *ipcc,
FAR char *buffer, size_t buflen);
/**************************************************************************
* Name: write
*
* Description:
* Writes data directly to IPCC mbox, function shall not block.
* If IPCC memory is full, or busy or otherwise unavailable for
* write, 0 shall be returned. Partial write is possible. In
* that case function can return value less then buflen.
*
* Input Parameters:
* ipcc - ipcc channel to write data to
* buffer - location to read data from
* buflen - number of bytes to write from buffer
*
* Returned Value:
* Number of actually written data to IPCC channel.
*
**************************************************************************/
CODE ssize_t (*write)(FAR struct ipcc_lower_s *ipcc,
FAR const char *buffer, size_t buflen);
/**************************************************************************
* Name: buffer_data
*
* Description:
* Lower driver shall copy data from IPCC to cirbuf on demand.
* It does not have to copy all data (in case rxbuf is full), but
* it must keep internal pointer to track uncopied data, and copy
* what is left on the next call to this function.
*
* Input Parameters:
* ipcc - channel to buffer data
* rxbuf - circural buffer where data should be written to
*
* Returned Value:
* Number of bytes that were successfully written to rxbuf.
*
**************************************************************************/
#ifdef CONFIG_IPCC_BUFFERED
CODE ssize_t (*buffer_data)(FAR struct ipcc_lower_s *ipcc,
FAR struct circbuf_s *rxbuf);
#endif
/**************************************************************************
* Name: write_notify
*
* Description:
* Upper half driver notifies lower half driver that new data has been
* copied to circ buffer. This can be used by lower half to transfer
* data from buffer to IPCC memory.
*
* Input Parameters:
* ipcc - ipcc channel that wrote data.
*
* Returned Value:
* 0 on success, or negated errno otherwise
*
**************************************************************************/
#ifdef CONFIG_IPCC_BUFFERED
CODE ssize_t (*write_notify)(FAR struct ipcc_lower_s *ipcc);
#endif
/**************************************************************************
* Name: cleanup
*
* Description:
* Cleans up resources initialized by <arch>_ipcc_init(). If arch code
* malloc()ed any memory, this funciton is responsible of freeing it.
* After this function is called, ipcc driver will not access lower
* half pointer anymore.
*
* Input Parameters:
* ipcc - ipcc channel to cleanup
*
* Returned Value:
* Always OK
*
**************************************************************************/
CODE int (*cleanup)(FAR struct ipcc_lower_s *ipcc);
};
/* This structure defines the interface between upper and lower halves.
* Such instance is passed to ipcc_register() function after driver
* has been initialized, binding the upper and lower halves into one
* driver.
*/
struct ipcc_lower_s
{
/* Pointer to upper half part of the driver. This should be used only
* when calling ipcc_* upper half functions from lower half code.
* There should be no need to access upper half driver's fields from
* lower half context.
*/
FAR struct ipcc_driver_s *upper;
struct ipcc_ops_s ops; /* Arch specific functions */
int chan; /* IPCC channel */
#ifdef CONFIG_IPCC_BUFFERED
struct circbuf_s rxbuf; /* Receive buffer */
struct circbuf_s txbuf; /* Transmit buffer */
/* 1 - not all data could fit into buffer, some unread data is still
* in IPCC mbox. State of this variable is maintained by lower half,
* upper half only reads it to know when to inform lower driver that
* buffer got free.
*/
int overflow;
#endif /* CONFIG_IPCC_BUFFERED */
};
/****************************************************************************
* Public Functions Prototypes
****************************************************************************/
void ipcc_txfree_notify(FAR struct ipcc_driver_s *priv);
void ipcc_rxfree_notify(FAR struct ipcc_driver_s *priv);
#ifdef CONFIG_IPCC_BUFFERED
int ipcc_register(FAR struct ipcc_lower_s *ipcc, size_t rxbuflen,
size_t txbuflen);
#else
int ipcc_register(FAR struct ipcc_lower_s *ipcc);
#endif
#endif /* __INCLUDE_NUTTX_IPCC_H */