/* 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.
*/
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <rtems/imfs.h>
#include <rtems/thread.h>
#include <dev/can/canqueueimpl.h>
#include <dev/can/can.h>
#define can_interrupt_lock_acquire(bus) \
do { \
CAN_DEBUG_LOCK("acquiring lock\n"); \
real_can_interrupt_lock_acquire(bus); \
} while (0);
#define can_interrupt_lock_release(bus) \
do { \
CAN_DEBUG_LOCK("releasing lock\n"); \
real_can_interrupt_lock_release(bus); \
} while (0);
static ssize_t
can_bus_open(rtems_libio_t *iop, const char *path, int oflag, mode_t mode);
static ssize_t
can_bus_read(rtems_libio_t *iop, void *buffer, size_t count);
static ssize_t
can_bus_write(rtems_libio_t *iop, const void *buffer, size_t count);
static ssize_t
can_bus_ioctl(rtems_libio_t *iop, ioctl_command_t request, void *buffer);
static int can_xmit(struct can_bus *bus);
static int can_bus_create_sem(struct can_bus *);
static int try_sem(struct can_bus *);
static int take_sem(struct can_bus *);
static int give_sem(struct can_bus *);
static void can_bus_obtain(can_bus *bus)
{
CAN_DEBUG("can_bus_obtain Entry\n");
rtems_mutex_lock(&bus->mutex);
CAN_DEBUG("can_bus_obtain Exit\n");
}
static void can_bus_release(can_bus *bus)
{
CAN_DEBUG("can_bus_release Entry\n");
rtems_mutex_unlock(&bus->mutex);
CAN_DEBUG("can_bus_release Exit\n");
}
static void can_bus_destroy_mutex(struct can_bus *bus)
{
rtems_mutex_destroy(&bus->mutex);
}
static int can_bus_create_sem(struct can_bus *bus)
{
int ret = 0;
ret = rtems_semaphore_create(rtems_build_name('c', 'a', 'n', bus->index),
CAN_TX_BUF_COUNT, RTEMS_FIFO | RTEMS_COUNTING_SEMAPHORE | RTEMS_LOCAL,
0, &bus->tx_fifo_sem_id);
if (ret != 0) {
CAN_ERR("can_create_sem: rtems_semaphore_create failed %d\n", ret);
}
return ret;
}
static void can_bus_free_tx_semaphore(struct can_bus *bus)
{
rtems_semaphore_delete(bus->tx_fifo_sem_id);
}
static void real_can_interrupt_lock_acquire(struct can_bus *bus)
{
bus->can_dev_ops->dev_int(bus->priv, false);
can_bus_obtain(bus);
}
static void real_can_interrupt_lock_release(struct can_bus *bus)
{
can_bus_release(bus);
bus->can_dev_ops->dev_int(bus->priv, true);
}
static int take_sem(struct can_bus *bus)
{
int ret = rtems_semaphore_obtain(bus->tx_fifo_sem_id, RTEMS_WAIT,
RTEMS_NO_TIMEOUT);
#ifdef CAN_DEBUG_LOCK
if (ret == RTEMS_SUCCESSFUL) {
bus->sem_count++;
CAN_DEBUG_LOCK("take_sem: Semaphore count = %d\n", bus->sem_count);
if (bus->sem_count > CAN_TX_BUF_COUNT) {
CAN_ERR("take_sem error: sem_count is misleading\n");
return RTEMS_INTERNAL_ERROR;
}
}
#endif /* CAN_DEBUG_LOCK */
return ret;
}
static int give_sem(struct can_bus *bus)
{
int ret = rtems_semaphore_release(bus->tx_fifo_sem_id);
#ifdef CAN_DEBUG_LOCK
if (ret == RTEMS_SUCCESSFUL) {
bus->sem_count--;
CAN_DEBUG_LOCK("give_sem: Semaphore count = %d\n", bus->sem_count);
if (bus->sem_count < 0) {
CAN_ERR("give_sem error: sem_count is misleading\n");
return RTEMS_INTERNAL_ERROR;
}
}
#endif /* CAN_DEBUG_LOCK */
return ret;
}
static int try_sem(struct can_bus *bus)
{
int ret = rtems_semaphore_obtain(bus->tx_fifo_sem_id, RTEMS_NO_WAIT,
RTEMS_NO_TIMEOUT);
#ifdef CAN_DEBUG_LOCK
if (ret == RTEMS_SUCCESSFUL) {
bus->sem_count++;
CAN_DEBUG_LOCK("try_sem: Semaphore count = %d\n", bus->sem_count);
if (bus->sem_count > CAN_TX_BUF_COUNT) {
CAN_ERR("take_sem error: sem_count is misleading\n");
return RTEMS_INTERNAL_ERROR;
}
}
#endif /* CAN_DEBUG_LOCK */
return ret;
}
static ssize_t
can_bus_open(rtems_libio_t *iop, const char *path, int oflag, mode_t mode)
{
CAN_DEBUG("can_bus_open\n");
return 0;
}
/* Should be called only with CAN interrupts disabled */
int can_receive(struct can_bus *bus, struct can_msg *msg)
{
memcpy(&bus->can_rx_msg, msg, CAN_MSG_LEN(msg));
return CAN_MSG_LEN(msg);
}
/* FIXME: Should be modified to read count number of bytes, Now sending one can_msg */
static ssize_t can_bus_read(rtems_libio_t *iop, void *buffer, size_t count)
{
int len;
can_bus *bus = IMFS_generic_get_context_by_iop(iop);
if (bus == NULL) {
return -RTEMS_NOT_DEFINED;
}
struct can_msg *msg = (struct can_msg *)buffer;
len = CAN_MSG_LEN(&bus->can_rx_msg);
if (count < len) {
CAN_DEBUG("can_bus_read: buffer size is small min sizeof(struct can_msg) = %u\n",
sizeof(struct can_msg));
return -RTEMS_INVALID_SIZE;
}
can_interrupt_lock_acquire(bus);
memcpy(msg, &bus->can_rx_msg, len);
can_interrupt_lock_release(bus);
return len;
}
/* This function is a critical section and should be called
* with CAN interrupts disabled and mutually exclusive
*/
static int can_xmit(struct can_bus *bus)
{
int ret = RTEMS_SUCCESSFUL;
struct can_msg *msg = NULL;
CAN_DEBUG(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> can_xmit Entry\n");
while (1) {
CAN_DEBUG("can_dev_ops->dev_tx_ready\n");
if (bus->can_dev_ops->dev_tx_ready(bus->priv) != true) {
break;
}
CAN_DEBUG("can_tx_get_data_buf\n");
msg = can_bus_tx_get_data_buf(bus);
if (msg == NULL) {
break;
}
CAN_DEBUG("can_dev_ops->dev_tx\n");
ret = bus->can_dev_ops->dev_tx(bus->priv, msg);
if (ret != RTEMS_SUCCESSFUL) {
CAN_ERR("can_xmit: dev_send failed\n");
break;
}
ret = give_sem(bus);
if (ret != RTEMS_SUCCESSFUL) {
CAN_ERR("can_xmit: rtems_semaphore_release failed = %d\n", ret);
break;
}
}
CAN_DEBUG(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> can_xmit Exit\n");
return ret;
}
void can_print_msg(struct can_msg const *msg)
{
#ifdef CAN_DEBUG
CAN_DEBUG("\n----------------------------------------------------------------\n");
CAN_DEBUG("id = %d len = %d flags = 0x%08X\n", msg->id, msg->len, msg->flags);
CAN_DEBUG("msg->data[0] = 0x%08x\n", ((uint32_t *)msg->data)[0]);
CAN_DEBUG("msg->data[1] = 0x%08x\n", ((uint32_t *)msg->data)[1]);
for (int i = 0; i < msg->len; i++) {
CAN_DEBUG("%02x\n", ((char *)msg->data)[i]);
}
CAN_DEBUG("\n-----------------------------------------------------------------\n");
#endif /* CAN_DEBUG */
}
/* can_tx_done should be called only with CAN interrupts disabled */
int can_tx_done(struct can_bus *bus)
{
CAN_DEBUG("------------ can_tx_done Entry\n");
int ret = RTEMS_SUCCESSFUL;
if (bus->can_dev_ops->dev_tx_ready(bus->priv) == true) {
ret = can_xmit(bus);
}
CAN_DEBUG("------------ can_tx_done Exit\n");
return ret;
}
/* FIXME: Add support to send multiple CAN msgs for can_bus_write */
static ssize_t
can_bus_write(rtems_libio_t *iop, const void *buffer, size_t count)
{
can_bus *bus = IMFS_generic_get_context_by_iop(iop);
if (bus == NULL || bus->can_dev_ops->dev_tx == NULL) {
return -RTEMS_NOT_DEFINED;
}
int ret = RTEMS_SUCCESSFUL;
struct can_msg const *msg = buffer;
struct can_msg *fifo_buf = NULL;
uint32_t msg_size = CAN_MSG_LEN(msg);
CAN_DEBUG_TX("can_bus_write: can_msg_size = %u\n", msg_size);
if (msg_size > sizeof(struct can_msg)) {
CAN_ERR("can_bus_write:"
"can message len error msg_size = %u struct can_msg = %u\n",
msg_size, sizeof(struct can_msg));
return -RTEMS_INVALID_SIZE;
}
if ((iop->flags & O_NONBLOCK) != 0) {
ret = try_sem(bus);
if (ret != RTEMS_SUCCESSFUL) {
return -ret;
}
} else {
ret = take_sem(bus);
if (ret != RTEMS_SUCCESSFUL) {
CAN_ERR("can_bus_write: cannot take semaphore\n");
return -ret;
}
}
can_interrupt_lock_acquire(bus);
fifo_buf = can_bus_tx_get_empty_buf(bus);
if (fifo_buf == NULL) {
/* This error will not happen until buffer counts are not synchronized */
CAN_ERR("can_bus_write: Buffer counts are not synchronized with semaphore count\n");
ret = -RTEMS_INTERNAL_ERROR;
goto release_lock_and_return;
}
CAN_DEBUG_TX("can_bus_write: empty_count = %u\n", bus->tx_fifo.empty_count);
CAN_DEBUG_TX("can_bus_write: copying msg from application to driver buffer\n");
memcpy(fifo_buf, msg, msg_size);
if (bus->can_dev_ops->dev_tx_ready(bus->priv) == true) {
ret = can_xmit(bus);
if (ret != RTEMS_SUCCESSFUL) {
ret = -ret;
goto release_lock_and_return;
}
}
ret = msg_size;
release_lock_and_return:
can_interrupt_lock_release(bus);
return ret;
}
static ssize_t
can_bus_ioctl(rtems_libio_t *iop, ioctl_command_t request, void *buffer)
{
can_bus *bus = IMFS_generic_get_context_by_iop(iop);
if (bus == NULL || bus->can_dev_ops->dev_ioctl == NULL) {
return -RTEMS_NOT_DEFINED;
}
can_bus_obtain(bus);
bus->can_dev_ops->dev_ioctl(bus->priv, NULL, 0);
can_bus_release(bus);
return RTEMS_SUCCESSFUL;
}
static const rtems_filesystem_file_handlers_r can_bus_handler = {
.open_h = can_bus_open,
.close_h = rtems_filesystem_default_close,
.read_h = can_bus_read,
.write_h = can_bus_write,
.ioctl_h = can_bus_ioctl,
.lseek_h = rtems_filesystem_default_lseek,
.fstat_h = IMFS_stat,
.ftruncate_h = rtems_filesystem_default_ftruncate,
.fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
.fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
.fcntl_h = rtems_filesystem_default_fcntl,
.kqfilter_h = rtems_filesystem_default_kqfilter,
.mmap_h = rtems_filesystem_default_mmap,
.poll_h = rtems_filesystem_default_poll,
.readv_h = rtems_filesystem_default_readv,
.writev_h = rtems_filesystem_default_writev
};
static void can_bus_node_destroy(IMFS_jnode_t *node)
{
can_bus *bus;
bus = IMFS_generic_get_context_by_node(node);
(*bus->destroy)(bus);
IMFS_node_destroy_default(node);
}
static const
IMFS_node_control can_bus_node_control = IMFS_GENERIC_INITIALIZER(&can_bus_handler,
IMFS_node_initialize_generic, can_bus_node_destroy);
rtems_status_code can_bus_register(can_bus *bus, const char *bus_path)
{
int ret = RTEMS_SUCCESSFUL;
static uint8_t index = 0;
if (index == CAN_BUS_REG_MAX) {
CAN_ERR("can_bus_register: can bus registration limit reached\n");
return RTEMS_TOO_MANY;
}
bus->index = index++;
CAN_DEBUG("Registering CAN bus index = %u\n", bus->index);
ret = IMFS_make_generic_node(bus_path, S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO,
&can_bus_node_control, bus);
if (ret != RTEMS_SUCCESSFUL) {
CAN_ERR("can_bus_register: Creating node failed = %d\n", ret);
goto fail;
}
if ((ret = can_bus_create_sem(bus)) != RTEMS_SUCCESSFUL) {
CAN_ERR("can_bus_register: can_create_sem failed = %d\n", ret);
goto fail;
}
if ((ret = can_bus_create_tx_buffers(bus)) != RTEMS_SUCCESSFUL) {
CAN_ERR("can_bus_register: can_create_tx_buffers failed = %d\n", ret);
goto free_tx_semaphore;
}
return ret;
free_tx_semaphore:
rtems_semaphore_delete(bus->tx_fifo_sem_id);
fail:
can_bus_destroy_mutex(bus);
return ret;
}
static void can_bus_destroy(can_bus *bus)
{
can_bus_free_tx_buffers(bus);
can_bus_free_tx_semaphore(bus);
can_bus_destroy_mutex(bus);
}
static int can_bus_do_init(can_bus *bus, void (*destroy)(can_bus *bus))
{
rtems_mutex_init(&bus->mutex, "CAN Bus");
bus->destroy = can_bus_destroy;
return RTEMS_SUCCESSFUL;
}
static void can_bus_destroy_and_free(can_bus *bus)
{
can_bus_destroy(bus);
free(bus);
}
int can_bus_init(can_bus *bus)
{
memset(bus, 0, sizeof(*bus));
return can_bus_do_init(bus, can_bus_destroy);
}
can_bus *can_bus_alloc_and_init(size_t size)
{
can_bus *bus = NULL;
if (size >= sizeof(*bus)) {
bus = calloc(1, size);
if (bus == NULL) {
CAN_ERR("can_bus_alloc_and_init: calloc failed\b");
return NULL;
}
int rv = can_bus_do_init(bus, can_bus_destroy_and_free);
if (rv != 0) {
CAN_ERR("can_bus_alloc_and_init: can_bus_do_init failed\n");
return NULL;
}
}
return bus;
}