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// Generic handling of serial over CAN support
//
// Copyright (C) 2019 Eug Krashtan <eug.krashtan@gmail.com>
// Copyright (C) 2020 Pontus Borg <glpontus@gmail.com>
// Copyright (C) 2021 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include <string.h> // memcpy
#include "canbus.h" // canbus_set_uuid
#include "command.h" // DECL_CONSTANT
#include "sched.h" // sched_wake_task
static uint32_t canbus_assigned_id;
static uint8_t canbus_uuid[CANBUS_UUID_LEN];
/****************************************************************
* Data transmission over CAN
****************************************************************/
static struct task_wake canbus_tx_wake;
static uint8_t transmit_buf[96], transmit_pos, transmit_max;
void
canbus_notify_tx(void)
{
sched_wake_task(&canbus_tx_wake);
}
void
canbus_tx_task(void)
{
if (!sched_check_wake(&canbus_tx_wake))
return;
uint32_t id = canbus_assigned_id;
if (!id) {
transmit_pos = transmit_max = 0;
return;
}
uint32_t tpos = transmit_pos, tmax = transmit_max;
for (;;) {
int avail = tmax - tpos, now = avail > 8 ? 8 : avail;
if (avail <= 0)
break;
int ret = canbus_send(id + 1, now, &transmit_buf[tpos]);
if (ret <= 0)
break;
tpos += now;
}
transmit_pos = tpos;
}
DECL_TASK(canbus_tx_task);
// Encode and transmit a "response" message
void
console_sendf(const struct command_encoder *ce, va_list args)
{
// Verify space for message
uint32_t tpos = transmit_pos, tmax = transmit_max;
if (tpos >= tmax)
transmit_pos = transmit_max = tpos = tmax = 0;
uint32_t max_size = ce->max_size;
if (tmax + max_size > sizeof(transmit_buf)) {
if (tmax + max_size - tpos > sizeof(transmit_buf))
// Not enough space for message
return;
// Move buffer
tmax -= tpos;
memmove(&transmit_buf[0], &transmit_buf[tpos], tmax);
transmit_pos = tpos = 0;
transmit_max = tmax;
}
// Generate message
uint32_t msglen = command_encode_and_frame(&transmit_buf[tmax], ce, args);
// Start message transmit
transmit_max = tmax + msglen;
canbus_notify_tx();
}
/****************************************************************
* CAN command handling
****************************************************************/
static uint8_t receive_buf[192], receive_pos;
DECL_CONSTANT("RECEIVE_WINDOW", ARRAY_SIZE(receive_buf));
static void
can_process_data(uint32_t id, uint32_t len, uint8_t *data)
{
int rpos = receive_pos;
if (len > sizeof(receive_buf) - rpos)
len = sizeof(receive_buf) - rpos;
memcpy(&receive_buf[rpos], data, len);
receive_pos = rpos + len;
}
// Helper to retry sending until successful
static void
canbus_send_blocking(uint32_t id, uint32_t len, uint8_t *data)
{
for (;;) {
int ret = canbus_send(id, len, data);
if (ret >= 0)
return;
}
}
static void
can_process_ping(uint32_t id, uint32_t len, uint8_t *data)
{
canbus_send_blocking(canbus_assigned_id + 1, 0, NULL);
}
static void
can_process_reset(uint32_t id, uint32_t len, uint8_t *data)
{
uint32_t reset_id = data[0] | (data[1] << 8);
if (reset_id == canbus_assigned_id)
canbus_reboot();
}
static void
can_process_uuid(uint32_t id, uint32_t len, uint8_t *data)
{
if (canbus_assigned_id)
return;
canbus_send_blocking(CANBUS_ID_UUID_RESP, sizeof(canbus_uuid), canbus_uuid);
}
static void
can_process_set_id(uint32_t id, uint32_t len, uint8_t *data)
{
// compare my UUID with packet to check if this packet mine
if (memcmp(&data[2], canbus_uuid, sizeof(canbus_uuid)) == 0) {
canbus_assigned_id = data[0] | (data[1] << 8);
canbus_set_dataport(canbus_assigned_id);
}
}
static void
can_process(uint32_t id, uint32_t len, uint8_t *data)
{
if (id == canbus_assigned_id) {
if (len)
can_process_data(id, len, data);
else
can_process_ping(id, len, data);
} else if (id == CANBUS_ID_UUID) {
if (len)
can_process_reset(id, len, data);
else
can_process_uuid(id, len, data);
} else if (id==CANBUS_ID_SET) {
can_process_set_id(id, len, data);
}
}
/****************************************************************
* CAN packet reading
****************************************************************/
static struct task_wake canbus_rx_wake;
void
canbus_notify_rx(void)
{
sched_wake_task(&canbus_rx_wake);
}
void
canbus_rx_task(void)
{
if (!sched_check_wake(&canbus_rx_wake))
return;
// Read any pending CAN packets
for (;;) {
uint8_t data[8];
uint32_t id;
int ret = canbus_read(&id, data);
if (ret < 0)
break;
can_process(id, ret, data);
}
// Check for a complete message block and process it
uint_fast8_t rpos = receive_pos, pop_count;
int ret = command_find_and_dispatch(receive_buf, rpos, &pop_count);
if (ret) {
// Move buffer
int needcopy = rpos - pop_count;
if (needcopy) {
memmove(receive_buf, &receive_buf[pop_count], needcopy);
canbus_notify_rx();
}
rpos = needcopy;
}
receive_pos = rpos;
}
DECL_TASK(canbus_rx_task);
/****************************************************************
* Setup and shutdown
****************************************************************/
void
canbus_set_uuid(void *uuid)
{
memcpy(canbus_uuid, uuid, sizeof(canbus_uuid));
// Send initial message
can_process_uuid(0, 0, NULL);
}
void
canbus_shutdown(void)
{
canbus_notify_tx();
canbus_notify_rx();
}
DECL_SHUTDOWN(canbus_shutdown);
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