blob: 13d59c8154a193b2821c71a6751e7eedb5dae5d4 [file] [log] [blame]
/*
* Copyright (c) 2020 PHYTEC Messtechnik GmbH
* Copyright (c) 2021 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
/*
* This file is based on mb.c and mb_util.c from uC/Modbus Stack.
*
* uC/Modbus
* The Embedded Modbus Stack
*
* Copyright 2003-2020 Silicon Laboratories Inc. www.silabs.com
*
* SPDX-License-Identifier: APACHE-2.0
*
* This software is subject to an open source license and is distributed by
* Silicon Laboratories Inc. pursuant to the terms of the Apache License,
* Version 2.0 available at www.apache.org/licenses/LICENSE-2.0.
*/
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(modbus_serial, CONFIG_MODBUS_LOG_LEVEL);
#include <zephyr/kernel.h>
#include <string.h>
#include <zephyr/sys/byteorder.h>
#include <zephyr/sys/crc.h>
#include <modbus_internal.h>
static void modbus_serial_tx_on(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
if (cfg->de != NULL) {
gpio_pin_set(cfg->de->port, cfg->de->pin, 1);
}
uart_irq_tx_enable(cfg->dev);
}
static void modbus_serial_tx_off(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
uart_irq_tx_disable(cfg->dev);
if (cfg->de != NULL) {
gpio_pin_set(cfg->de->port, cfg->de->pin, 0);
}
}
static void modbus_serial_rx_on(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
if (cfg->re != NULL) {
gpio_pin_set(cfg->re->port, cfg->re->pin, 1);
}
uart_irq_rx_enable(cfg->dev);
}
static void modbus_serial_rx_off(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
uart_irq_rx_disable(cfg->dev);
if (cfg->re != NULL) {
gpio_pin_set(cfg->re->port, cfg->re->pin, 0);
}
}
#ifdef CONFIG_MODBUS_ASCII_MODE
/* The function calculates an 8-bit Longitudinal Redundancy Check. */
static uint8_t modbus_ascii_get_lrc(uint8_t *src, size_t length)
{
uint8_t lrc = 0;
uint8_t tmp;
uint8_t *pblock = src;
while (length-- > 0) {
/* Add the data byte to LRC, increment data pointer. */
if (hex2bin(pblock, 2, &tmp, sizeof(tmp)) != sizeof(tmp)) {
return 0;
}
lrc += tmp;
pblock += 2;
}
/* Two complement the binary sum */
lrc = ~lrc + 1;
return lrc;
}
/* Parses and converts an ASCII mode frame into a Modbus RTU frame. */
static int modbus_ascii_rx_adu(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
uint8_t *pmsg;
uint8_t *prx_data;
uint16_t rx_size;
uint8_t frame_lrc;
uint8_t calc_lrc;
rx_size = cfg->uart_buf_ctr;
prx_data = &ctx->rx_adu.data[0];
if (!(rx_size & 0x01)) {
LOG_WRN("Message should have an odd number of bytes");
return -EMSGSIZE;
}
if (rx_size < MODBUS_ASCII_MIN_MSG_SIZE) {
LOG_WRN("Frame length error");
return -EMSGSIZE;
}
if ((cfg->uart_buf[0] != MODBUS_ASCII_START_FRAME_CHAR) ||
(cfg->uart_buf[rx_size - 2] != MODBUS_ASCII_END_FRAME_CHAR1) ||
(cfg->uart_buf[rx_size - 1] != MODBUS_ASCII_END_FRAME_CHAR2)) {
LOG_WRN("Frame character error");
return -EMSGSIZE;
}
/* Take away for the ':', CR, and LF */
rx_size -= 3;
/* Point past the ':' to the address. */
pmsg = &cfg->uart_buf[1];
hex2bin(pmsg, 2, &ctx->rx_adu.unit_id, 1);
pmsg += 2;
rx_size -= 2;
hex2bin(pmsg, 2, &ctx->rx_adu.fc, 1);
pmsg += 2;
rx_size -= 2;
/* Get the data from the message */
ctx->rx_adu.length = 0;
while (rx_size > 2) {
hex2bin(pmsg, 2, prx_data, 1);
prx_data++;
pmsg += 2;
rx_size -= 2;
/* Increment the number of Modbus packets received */
ctx->rx_adu.length++;
}
/* Extract the message's LRC */
hex2bin(pmsg, 2, &frame_lrc, 1);
ctx->rx_adu.crc = frame_lrc;
/*
* The LRC is calculated on the ADDR, FC and Data fields,
* not the ':', CR/LF and LRC placed in the message
* by the sender. We thus need to subtract 5 'ASCII' characters
* from the received message to exclude these.
*/
calc_lrc = modbus_ascii_get_lrc(&cfg->uart_buf[1],
(cfg->uart_buf_ctr - 5) / 2);
if (calc_lrc != frame_lrc) {
LOG_ERR("Calculated LRC does not match received LRC");
return -EIO;
}
return 0;
}
static uint8_t *modbus_ascii_bin2hex(uint8_t value, uint8_t *pbuf)
{
uint8_t u_nibble = (value >> 4) & 0x0F;
uint8_t l_nibble = value & 0x0F;
hex2char(u_nibble, pbuf);
pbuf++;
hex2char(l_nibble, pbuf);
pbuf++;
return pbuf;
}
static void modbus_ascii_tx_adu(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
uint16_t tx_bytes = 0;
uint8_t lrc;
uint8_t *pbuf;
/* Place the start-of-frame character into output buffer */
cfg->uart_buf[0] = MODBUS_ASCII_START_FRAME_CHAR;
tx_bytes = 1;
pbuf = &cfg->uart_buf[1];
pbuf = modbus_ascii_bin2hex(ctx->tx_adu.unit_id, pbuf);
tx_bytes += 2;
pbuf = modbus_ascii_bin2hex(ctx->tx_adu.fc, pbuf);
tx_bytes += 2;
for (int i = 0; i < ctx->tx_adu.length; i++) {
pbuf = modbus_ascii_bin2hex(ctx->tx_adu.data[i], pbuf);
tx_bytes += 2;
}
/*
* Add the LRC checksum in the packet.
*
* The LRC is calculated on the ADDR, FC and Data fields,
* not the ':' which was inserted in the uart_buf[].
* Thus we subtract 1 ASCII character from the LRC.
* The LRC and CR/LF bytes are not YET in the .uart_buf[].
*/
lrc = modbus_ascii_get_lrc(&cfg->uart_buf[1], (tx_bytes - 1) / 2);
pbuf = modbus_ascii_bin2hex(lrc, pbuf);
tx_bytes += 2;
*pbuf++ = MODBUS_ASCII_END_FRAME_CHAR1;
*pbuf++ = MODBUS_ASCII_END_FRAME_CHAR2;
tx_bytes += 2;
/* Update the total number of bytes to send */
cfg->uart_buf_ctr = tx_bytes;
cfg->uart_buf_ptr = &cfg->uart_buf[0];
LOG_DBG("Start frame transmission");
modbus_serial_rx_off(ctx);
modbus_serial_tx_on(ctx);
}
#else
static int modbus_ascii_rx_adu(struct modbus_context *ctx)
{
return 0;
}
static void modbus_ascii_tx_adu(struct modbus_context *ctx)
{
}
#endif
/* Copy Modbus RTU frame and check if the CRC is valid. */
static int modbus_rtu_rx_adu(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
uint16_t calc_crc;
uint16_t crc_idx;
uint8_t *data_ptr;
/* Is the message long enough? */
if ((cfg->uart_buf_ctr < MODBUS_RTU_MIN_MSG_SIZE) ||
(cfg->uart_buf_ctr > CONFIG_MODBUS_BUFFER_SIZE)) {
LOG_WRN("Frame length error");
return -EMSGSIZE;
}
ctx->rx_adu.unit_id = cfg->uart_buf[0];
ctx->rx_adu.fc = cfg->uart_buf[1];
data_ptr = &cfg->uart_buf[2];
/* Payload length without node address, function code, and CRC */
ctx->rx_adu.length = cfg->uart_buf_ctr - 4;
/* CRC index */
crc_idx = cfg->uart_buf_ctr - sizeof(uint16_t);
memcpy(ctx->rx_adu.data, data_ptr, ctx->rx_adu.length);
ctx->rx_adu.crc = sys_get_le16(&cfg->uart_buf[crc_idx]);
/* Calculate CRC over address, function code, and payload */
calc_crc = crc16_ansi(&cfg->uart_buf[0],
cfg->uart_buf_ctr - sizeof(ctx->rx_adu.crc));
if (ctx->rx_adu.crc != calc_crc) {
LOG_WRN("Calculated CRC does not match received CRC");
return -EIO;
}
return 0;
}
static void rtu_tx_adu(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
uint16_t tx_bytes = 0;
uint8_t *data_ptr;
cfg->uart_buf[0] = ctx->tx_adu.unit_id;
cfg->uart_buf[1] = ctx->tx_adu.fc;
tx_bytes = 2 + ctx->tx_adu.length;
data_ptr = &cfg->uart_buf[2];
memcpy(data_ptr, ctx->tx_adu.data, ctx->tx_adu.length);
ctx->tx_adu.crc = crc16_ansi(&cfg->uart_buf[0], ctx->tx_adu.length + 2);
sys_put_le16(ctx->tx_adu.crc,
&cfg->uart_buf[ctx->tx_adu.length + 2]);
tx_bytes += 2;
cfg->uart_buf_ctr = tx_bytes;
cfg->uart_buf_ptr = &cfg->uart_buf[0];
LOG_HEXDUMP_DBG(cfg->uart_buf, cfg->uart_buf_ctr, "uart_buf");
LOG_DBG("Start frame transmission");
modbus_serial_rx_off(ctx);
modbus_serial_tx_on(ctx);
}
/*
* A byte has been received from a serial port. We just store it in the buffer
* for processing when a complete packet has been received.
*/
static void cb_handler_rx(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
if ((ctx->mode == MODBUS_MODE_ASCII) &&
IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
uint8_t c;
if (uart_fifo_read(cfg->dev, &c, 1) != 1) {
LOG_ERR("Failed to read UART");
return;
}
if (c == MODBUS_ASCII_START_FRAME_CHAR) {
/* Restart a new frame */
cfg->uart_buf_ptr = &cfg->uart_buf[0];
cfg->uart_buf_ctr = 0;
}
if (cfg->uart_buf_ctr < CONFIG_MODBUS_BUFFER_SIZE) {
*cfg->uart_buf_ptr++ = c;
cfg->uart_buf_ctr++;
}
if (c == MODBUS_ASCII_END_FRAME_CHAR2) {
k_work_submit(&ctx->server_work);
}
} else {
int n;
/* Restart timer on a new character */
k_timer_start(&cfg->rtu_timer,
K_USEC(cfg->rtu_timeout), K_NO_WAIT);
n = uart_fifo_read(cfg->dev, cfg->uart_buf_ptr,
(CONFIG_MODBUS_BUFFER_SIZE -
cfg->uart_buf_ctr));
cfg->uart_buf_ptr += n;
cfg->uart_buf_ctr += n;
}
}
static void cb_handler_tx(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
int n;
if (cfg->uart_buf_ctr > 0) {
n = uart_fifo_fill(cfg->dev, cfg->uart_buf_ptr,
cfg->uart_buf_ctr);
cfg->uart_buf_ctr -= n;
cfg->uart_buf_ptr += n;
return;
}
/* Must wait till the transmission is complete or
* RS-485 transceiver could be disabled before all data has
* been transmitted and message will be corrupted.
*/
if (uart_irq_tx_complete(cfg->dev)) {
/* Disable transmission */
cfg->uart_buf_ptr = &cfg->uart_buf[0];
modbus_serial_tx_off(ctx);
modbus_serial_rx_on(ctx);
}
}
static void uart_cb_handler(const struct device *dev, void *app_data)
{
struct modbus_context *ctx = (struct modbus_context *)app_data;
struct modbus_serial_config *cfg;
if (ctx == NULL) {
LOG_ERR("Modbus hardware is not properly initialized");
return;
}
cfg = ctx->cfg;
if (uart_irq_update(cfg->dev) && uart_irq_is_pending(cfg->dev)) {
if (uart_irq_rx_ready(cfg->dev)) {
cb_handler_rx(ctx);
}
if (uart_irq_tx_ready(cfg->dev)) {
cb_handler_tx(ctx);
}
}
}
/* This function is called when the RTU framing timer expires. */
static void rtu_tmr_handler(struct k_timer *t_id)
{
struct modbus_context *ctx;
ctx = (struct modbus_context *)k_timer_user_data_get(t_id);
if (ctx == NULL) {
LOG_ERR("Failed to get Modbus context");
return;
}
k_work_submit(&ctx->server_work);
}
static int configure_gpio(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
if (cfg->de != NULL) {
if (!device_is_ready(cfg->de->port)) {
return -ENODEV;
}
if (gpio_pin_configure_dt(cfg->de, GPIO_OUTPUT_INACTIVE)) {
return -EIO;
}
}
if (cfg->re != NULL) {
if (!device_is_ready(cfg->re->port)) {
return -ENODEV;
}
if (gpio_pin_configure_dt(cfg->re, GPIO_OUTPUT_INACTIVE)) {
return -EIO;
}
}
return 0;
}
static inline int configure_uart(struct modbus_context *ctx,
struct modbus_iface_param *param)
{
struct modbus_serial_config *cfg = ctx->cfg;
struct uart_config uart_cfg = {
.baudrate = param->serial.baud,
.flow_ctrl = UART_CFG_FLOW_CTRL_NONE,
};
if (ctx->mode == MODBUS_MODE_ASCII) {
uart_cfg.data_bits = UART_CFG_DATA_BITS_7;
} else {
uart_cfg.data_bits = UART_CFG_DATA_BITS_8;
}
switch (param->serial.parity) {
case UART_CFG_PARITY_ODD:
case UART_CFG_PARITY_EVEN:
uart_cfg.parity = param->serial.parity;
uart_cfg.stop_bits = UART_CFG_STOP_BITS_1;
break;
case UART_CFG_PARITY_NONE:
/* Use of no parity requires 2 stop bits */
uart_cfg.parity = param->serial.parity;
uart_cfg.stop_bits = UART_CFG_STOP_BITS_2;
break;
default:
return -EINVAL;
}
if (ctx->client) {
/* Allow custom stop bit settings only in client mode */
switch (param->serial.stop_bits_client) {
case UART_CFG_STOP_BITS_0_5:
case UART_CFG_STOP_BITS_1:
case UART_CFG_STOP_BITS_1_5:
case UART_CFG_STOP_BITS_2:
uart_cfg.stop_bits = param->serial.stop_bits_client;
break;
default:
return -EINVAL;
}
}
if (uart_configure(cfg->dev, &uart_cfg) != 0) {
LOG_ERR("Failed to configure UART");
return -EINVAL;
}
return 0;
}
void modbus_serial_rx_disable(struct modbus_context *ctx)
{
modbus_serial_rx_off(ctx);
}
void modbus_serial_rx_enable(struct modbus_context *ctx)
{
modbus_serial_rx_on(ctx);
}
int modbus_serial_rx_adu(struct modbus_context *ctx)
{
struct modbus_serial_config *cfg = ctx->cfg;
int rc = 0;
switch (ctx->mode) {
case MODBUS_MODE_RTU:
rc = modbus_rtu_rx_adu(ctx);
break;
case MODBUS_MODE_ASCII:
if (!IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
return -ENOTSUP;
}
rc = modbus_ascii_rx_adu(ctx);
break;
default:
LOG_ERR("Unsupported MODBUS mode");
return -ENOTSUP;
}
cfg->uart_buf_ctr = 0;
cfg->uart_buf_ptr = &cfg->uart_buf[0];
return rc;
}
int modbus_serial_tx_adu(struct modbus_context *ctx)
{
switch (ctx->mode) {
case MODBUS_MODE_RTU:
rtu_tx_adu(ctx);
return 0;
case MODBUS_MODE_ASCII:
if (IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
modbus_ascii_tx_adu(ctx);
return 0;
}
default:
break;
}
return -ENOTSUP;
}
int modbus_serial_init(struct modbus_context *ctx,
struct modbus_iface_param param)
{
struct modbus_serial_config *cfg = ctx->cfg;
const uint32_t if_delay_max = 3500000;
const uint32_t numof_bits = 11;
switch (param.mode) {
case MODBUS_MODE_RTU:
case MODBUS_MODE_ASCII:
ctx->mode = param.mode;
break;
default:
return -ENOTSUP;
}
if (!device_is_ready(cfg->dev)) {
LOG_ERR("Bus device %s is not ready", cfg->dev->name);
return -ENODEV;
}
if (IS_ENABLED(CONFIG_UART_USE_RUNTIME_CONFIGURE)) {
if (configure_uart(ctx, &param) != 0) {
return -EINVAL;
}
}
if (param.serial.baud <= 38400) {
cfg->rtu_timeout = (numof_bits * if_delay_max) /
param.serial.baud;
} else {
cfg->rtu_timeout = (numof_bits * if_delay_max) / 38400;
}
if (configure_gpio(ctx) != 0) {
return -EIO;
}
cfg->uart_buf_ctr = 0;
cfg->uart_buf_ptr = &cfg->uart_buf[0];
uart_irq_callback_user_data_set(cfg->dev, uart_cb_handler, ctx);
k_timer_init(&cfg->rtu_timer, rtu_tmr_handler, NULL);
k_timer_user_data_set(&cfg->rtu_timer, ctx);
modbus_serial_rx_on(ctx);
LOG_INF("RTU timeout %u us", cfg->rtu_timeout);
return 0;
}
void modbus_serial_disable(struct modbus_context *ctx)
{
modbus_serial_tx_off(ctx);
modbus_serial_rx_off(ctx);
k_timer_stop(&ctx->cfg->rtu_timer);
}