/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup CANBus
*
* @brief Controller Area Network (CAN) Bus Implementation
*
*/
/*
* Copyright (C) 2022 Prashanth S <fishesprashanth@gmail.com>
*
* 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.
*
* 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.
*/
#ifndef _DEV_CAN_CAN_QUEUE_H
#define _DEV_CAN_CAN_QUEUE_H
#include <rtems/imfs.h>
#include <rtems/thread.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <dev/can/can-msg.h>
#include <dev/can/can.h>
/**
* @defgroup Controller Area Network (CAN) Driver
*
* @ingroup RTEMSDeviceDrivers
*
* @brief Controller Area Network (CAN) bus and device driver support.
*
* @{
*/
/**
* @defgroup CANBus CAN Bus Driver
*
* @ingroup CAN
*
* @{
*/
/**
* @brief Create CAN tx buffers.
*
* @param[in] bus Bus control structure.
*
* @retval 0 Successful operation.
* @retval >0 error number in case of an error.
*/
static rtems_status_code can_bus_create_tx_buffers(struct can_bus *bus);
/**
* @brief Free CAN tx buffers.
*
* @param[in] bus Bus control structure.
*
*/
static void can_bus_free_tx_buffers(struct can_bus *bus);
/**
* @brief Check for atleast one empty CAN tx buffer.
*
* @param[in] bus Bus control structure.
*
* @retval true If atleast one CAN buffer is empty.
* @retval false If no CAN buffer is empty.
*/
static bool can_bus_tx_buf_is_empty(struct can_bus *bus);
/**
* @brief Get a produced tx buffer to transmit from the tx fifo.
*
* @param[in] bus Bus control structure.
*
* @retval can_msg Pointer to can_msg structure buffer.
* @retval NULL If no can_msg buffer.
*/
static struct can_msg *can_bus_tx_get_data_buf(struct can_bus *bus);
/**
* @brief Get a empty tx buffer.
*
* @param[in] bus Bus control structure.
*
* @retval can_msg Pointer to can_msg structure buffer.
* @retval NULL If no empty can_msg buffer.
*/
static struct can_msg *can_bus_tx_get_empty_buf(struct can_bus *bus);
/**
* @brief Creates tx buffers for the CAN bus driver.
*
* @param[in] bus Bus control structure.
*
* @retval rtems_status_code
*/
static rtems_status_code can_bus_create_tx_buffers(struct can_bus *bus)
{
bus->tx_fifo.pbuf = (struct can_msg *)malloc(CAN_TX_BUF_COUNT *
sizeof(struct can_msg));
if (bus->tx_fifo.pbuf == NULL) {
CAN_ERR("can_create_tx_buffers: malloc failed\n");
return RTEMS_NO_MEMORY;
}
bus->tx_fifo.empty_count = CAN_TX_BUF_COUNT;
return RTEMS_SUCCESSFUL;
}
/**
* @brief Free tx buffers for the CAN bus driver.
*
* @param[in] bus Bus control structure.
*
*/
static void can_bus_free_tx_buffers(struct can_bus *bus)
{
free(bus->tx_fifo.pbuf);
}
/**
* @brief Check if there is atleast one tx buffer in the CAN
* bus driver.
*
* @param[in] bus Bus control structure.
*
* @retval true - If there is at least one free tx buffer.
* false - If there is no free tx buffer.
*/
static bool can_bus_tx_buf_is_empty(struct can_bus *bus)
{
if (bus->tx_fifo.empty_count == 0) {
return false;
}
return true;
}
/**
* @brief To get a can_msg tx buf which contains valid data to send in
* in the CAN bus.
*
* Note: freeing the returned data buf is done in the same function,
* So the returned buffer should be sent before releasing the
* lock acquired while calling this function.
*
* @param[in] bus Bus control structure.
*
* @retval *can_msg - If there is atleast one tx buffer to send in the CAN bus.
* NULL - If there is no valid tx buffer.
*/
static struct can_msg *can_bus_tx_get_data_buf(struct can_bus *bus)
{
struct can_msg *msg = NULL;
if (bus->tx_fifo.empty_count == CAN_TX_BUF_COUNT ||
bus->tx_fifo.tail >= CAN_TX_BUF_COUNT) {
CAN_DEBUG_BUF("can_bus_tx_get_data_buf: All buffers are empty\n");
return NULL;
}
msg = &bus->tx_fifo.pbuf[bus->tx_fifo.tail];
bus->tx_fifo.empty_count++;
bus->tx_fifo.tail = (bus->tx_fifo.tail + 1) % CAN_TX_BUF_COUNT;
return msg;
}
/**
* @brief To get a can_msg tx buf which is empty (contains no valid data).
*
* Note: marking the returned buf valid is done in the same function
* So a valid CAN message should be copied to the returned buffer before
* releasing the lock acquired while calling this function.
*
* @param[in] bus Bus control structure.
*
* @retval *can_msg - If there is atleast one empty tx buffer.
* NULL - If there is no empty tx buffer.
*/
static struct can_msg *can_bus_tx_get_empty_buf(struct can_bus *bus)
{
struct can_msg *msg = NULL;
/* Check whether there is a empty CAN msg buffer */
if (can_bus_tx_buf_is_empty(bus) == false) {
CAN_DEBUG_BUF("can_bus_tx_get_empty_buf: No empty buffer\n");
return NULL;
}
bus->tx_fifo.empty_count--;
/* tx_fifo.head always points to a empty buffer if there is atleast one */
msg = &bus->tx_fifo.pbuf[bus->tx_fifo.head];
bus->tx_fifo.head = (bus->tx_fifo.head + 1) % CAN_TX_BUF_COUNT;
return msg;
}
/** @} */ /* end of CAN device driver */
/** @} */
#endif /*_DEV_CAN_CAN_QUEUE_H */
