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modbus: move MODBUS over serial line code to own file

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Move MODBUS over serial line code to own source file.

Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>
This commit is contained in:
Johann Fischer 2021-03-03 13:43:48 +01:00 • committed by Carles Cufí
commit 3ddb47cc43
4 changed files with 632 additions and 546 deletions
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1
subsys/modbus/CMakeLists.txt
View file

@ -8,6 +8,7 @@ if(CONFIG_MODBUS)
zephyr_library_sources(
modbus_core.c
modbus_serial.c
)
zephyr_library_sources_ifdef(

583
subsys/modbus/modbus_core.c
View file

@ -1,24 +1,10 @@
/*
* 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 <logging/log.h>
LOG_MODULE_REGISTER(modbus, CONFIG_MODBUS_LOG_LEVEL);
@ -59,514 +45,63 @@ static struct modbus_context mb_ctx_tbl[] = {
DT_INST_FOREACH_STATUS_OKAY(MODBUS_DT_GET_DEV)
};
static void mb_tx_enable(struct modbus_context *ctx)
static void modbus_rx_handler(struct k_work *item)
{
if (ctx->de != NULL) {
gpio_pin_set(ctx->de->dev, ctx->de->pin, 1);
struct modbus_context *ctx;
ctx = CONTAINER_OF(item, struct modbus_context, server_work);
if (ctx == NULL) {
LOG_ERR("Failed to obtain context pointer?");
return;
}
uart_irq_tx_enable(ctx->dev);
}
static void mb_tx_disable(struct modbus_context *ctx)
{
uart_irq_tx_disable(ctx->dev);
if (ctx->de != NULL) {
gpio_pin_set(ctx->de->dev, ctx->de->pin, 0);
}
}
static void mb_rx_enable(struct modbus_context *ctx)
{
if (ctx->re != NULL) {
gpio_pin_set(ctx->re->dev, ctx->re->pin, 1);
switch (ctx->mode) {
case MODBUS_MODE_RTU:
case MODBUS_MODE_ASCII:
modbus_serial_rx_disable(ctx);
ctx->rx_frame_err = modbus_serial_rx_frame(ctx);
break;
default:
LOG_ERR("Unknown MODBUS mode");
return;
}
uart_irq_rx_enable(ctx->dev);
}
static void mb_rx_disable(struct modbus_context *ctx)
{
uart_irq_rx_disable(ctx->dev);
if (ctx->re != NULL) {
gpio_pin_set(ctx->re->dev, ctx->re->pin, 0);
}
}
#ifdef CONFIG_MODBUS_ASCII_MODE
/* The function calculates an 8-bit Longitudinal Redundancy Check. */
static uint8_t mb_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;
if (ctx->client == true) {
k_sem_give(&ctx->client_wait_sem);
return;
}
/* Two complement the binary sum */
lrc = ~lrc + 1;
if (IS_ENABLED(CONFIG_MODBUS_SERVER)) {
bool respond = mbs_rx_handler(ctx);
return lrc;
}
/* Parses and converts an ASCII mode frame into a Modbus RTU frame. */
static int mb_rx_ascii_frame(struct modbus_context *ctx)
{
uint8_t *pmsg;
uint8_t *prx_data;
uint16_t rx_size;
uint8_t frame_lrc;
uint8_t calc_lrc;
rx_size = ctx->uart_buf_ctr;
prx_data = &ctx->rx_frame.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 ((ctx->uart_buf[0] != MODBUS_ASCII_START_FRAME_CHAR) ||
(ctx->uart_buf[rx_size - 2] != MODBUS_ASCII_END_FRAME_CHAR1) ||
(ctx->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 = &ctx->uart_buf[1];
hex2bin(pmsg, 2, &ctx->rx_frame.addr, 1);
pmsg += 2;
rx_size -= 2;
hex2bin(pmsg, 2, &ctx->rx_frame.fc, 1);
pmsg += 2;
rx_size -= 2;
/* Get the data from the message */
ctx->rx_frame.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_frame.length++;
}
/* Extract the message's LRC */
hex2bin(pmsg, 2, &frame_lrc, 1);
ctx->rx_frame.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 = mb_ascii_get_lrc(&ctx->uart_buf[1],
(ctx->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 *mb_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 mb_tx_ascii_frame(struct modbus_context *ctx)
{
uint16_t tx_bytes = 0;
uint8_t lrc;
uint8_t *pbuf;
/* Place the start-of-frame character into output buffer */
ctx->uart_buf[0] = MODBUS_ASCII_START_FRAME_CHAR;
tx_bytes = 1;
pbuf = &ctx->uart_buf[1];
pbuf = mb_bin2hex(ctx->tx_frame.addr, pbuf);
tx_bytes += 2;
pbuf = mb_bin2hex(ctx->tx_frame.fc, pbuf);
tx_bytes += 2;
for (int i = 0; i < ctx->tx_frame.length; i++) {
pbuf = mb_bin2hex(ctx->tx_frame.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 = mb_ascii_get_lrc(&ctx->uart_buf[1], (tx_bytes - 1) / 2);
pbuf = mb_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 */
ctx->uart_buf_ctr = tx_bytes;
ctx->uart_buf_ptr = &ctx->uart_buf[0];
LOG_DBG("Start frame transmission");
mb_rx_disable(ctx);
mb_tx_enable(ctx);
}
#else
static int mb_rx_ascii_frame(struct modbus_context *ctx)
{
return 0;
}
static void mb_tx_ascii_frame(struct modbus_context *ctx)
{
}
#endif
static uint16_t mb_rtu_crc16(uint8_t *src, size_t length)
{
uint16_t crc = 0xFFFF;
uint8_t shiftctr;
bool flag;
uint8_t *pblock = src;
while (length > 0) {
length--;
crc ^= (uint16_t)*pblock++;
shiftctr = 8;
do {
/* Determine if the shift out of rightmost bit is 1 */
flag = (crc & 0x0001) ? true : false;
/* Shift CRC to the right one bit. */
crc >>= 1;
/*
* If bit shifted out of rightmost bit was a 1
* exclusive OR the CRC with the generating polynomial.
*/
if (flag == true) {
crc ^= MODBUS_CRC16_POLY;
switch (ctx->mode) {
case MODBUS_MODE_RTU:
case MODBUS_MODE_ASCII:
if (respond == false) {
LOG_DBG("Server has dropped frame");
modbus_serial_rx_enable(ctx);
}
shiftctr--;
} while (shiftctr > 0);
break;
default:
break;
}
}
return crc;
}
/* Copy Modbus RTU frame and check if the CRC is valid. */
static int mb_rx_rtu_frame(struct modbus_context *ctx)
{
uint16_t calc_crc;
uint16_t crc_idx;
uint8_t *data_ptr;
/* Is the message long enough? */
if ((ctx->uart_buf_ctr < MODBUS_RTU_MIN_MSG_SIZE) ||
(ctx->uart_buf_ctr > CONFIG_MODBUS_BUFFER_SIZE)) {
LOG_WRN("Frame length error");
return -EMSGSIZE;
}
ctx->rx_frame.addr = ctx->uart_buf[0];
ctx->rx_frame.fc = ctx->uart_buf[1];
data_ptr = &ctx->uart_buf[2];
/* Payload length without node address, function code, and CRC */
ctx->rx_frame.length = ctx->uart_buf_ctr - 4;
/* CRC index */
crc_idx = ctx->uart_buf_ctr - sizeof(uint16_t);
memcpy(ctx->rx_frame.data, data_ptr, ctx->rx_frame.length);
ctx->rx_frame.crc = sys_get_le16(&ctx->uart_buf[crc_idx]);
/* Calculate CRC over address, function code, and payload */
calc_crc = mb_rtu_crc16(&ctx->uart_buf[0],
ctx->uart_buf_ctr - sizeof(ctx->rx_frame.crc));
if (ctx->rx_frame.crc != calc_crc) {
LOG_WRN("Calculated CRC does not match received CRC");
return -EIO;
}
return 0;
}
static void mb_tx_rtu_frame(struct modbus_context *ctx)
{
uint16_t tx_bytes = 0;
uint8_t *data_ptr;
ctx->uart_buf[0] = ctx->tx_frame.addr;
ctx->uart_buf[1] = ctx->tx_frame.fc;
tx_bytes = 2 + ctx->tx_frame.length;
data_ptr = &ctx->uart_buf[2];
memcpy(data_ptr, ctx->tx_frame.data, ctx->tx_frame.length);
ctx->tx_frame.crc = mb_rtu_crc16(&ctx->uart_buf[0],
ctx->tx_frame.length + 2);
sys_put_le16(ctx->tx_frame.crc,
&ctx->uart_buf[ctx->tx_frame.length + 2]);
tx_bytes += 2;
ctx->uart_buf_ctr = tx_bytes;
ctx->uart_buf_ptr = &ctx->uart_buf[0];
LOG_HEXDUMP_DBG(ctx->uart_buf, ctx->uart_buf_ctr, "uart_buf");
LOG_DBG("Start frame transmission");
mb_rx_disable(ctx);
mb_tx_enable(ctx);
}
void mb_tx_frame(struct modbus_context *ctx)
{
switch (ctx->mode) {
case MODBUS_MODE_RTU:
mb_tx_rtu_frame(ctx);
break;
case MODBUS_MODE_ASCII:
if (IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
mb_tx_ascii_frame(ctx);
break;
if (modbus_serial_tx_frame(ctx)) {
LOG_ERR("Unsupported MODBUS serial mode");
}
break;
default:
LOG_ERR("Unknown MODBUS mode");
return;
}
}
/*
* 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 mb_cb_handler_rx(struct modbus_context *ctx)
{
if ((ctx->mode == MODBUS_MODE_ASCII) &&
IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
uint8_t c;
if (uart_fifo_read(ctx->dev, &c, 1) != 1) {
LOG_ERR("Failed to read UART");
return;
}
if (c == MODBUS_ASCII_START_FRAME_CHAR) {
/* Restart a new frame */
ctx->uart_buf_ptr = &ctx->uart_buf[0];
ctx->uart_buf_ctr = 0;
}
if (ctx->uart_buf_ctr < CONFIG_MODBUS_BUFFER_SIZE) {
*ctx->uart_buf_ptr++ = c;
ctx->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(&ctx->rtu_timer,
K_USEC(ctx->rtu_timeout), K_NO_WAIT);
n = uart_fifo_read(ctx->dev, ctx->uart_buf_ptr,
(CONFIG_MODBUS_BUFFER_SIZE -
ctx->uart_buf_ctr));
ctx->uart_buf_ptr += n;
ctx->uart_buf_ctr += n;
}
}
static void mb_cb_handler_tx(struct modbus_context *ctx)
{
int n;
if (ctx->uart_buf_ctr > 0) {
n = uart_fifo_fill(ctx->dev, ctx->uart_buf_ptr,
ctx->uart_buf_ctr);
ctx->uart_buf_ctr -= n;
ctx->uart_buf_ptr += n;
} else {
/* Disable transmission */
ctx->uart_buf_ptr = &ctx->uart_buf[0];
mb_tx_disable(ctx);
mb_rx_enable(ctx);
}
}
static void mb_uart_cb_handler(const struct device *dev, void *app_data)
{
struct modbus_context *ctx = (struct modbus_context *)app_data;
if (ctx == NULL) {
LOG_ERR("Modbus hardware is not properly initialized");
return;
}
while (uart_irq_update(ctx->dev) && uart_irq_is_pending(ctx->dev)) {
if (uart_irq_rx_ready(ctx->dev)) {
mb_cb_handler_rx(ctx);
}
if (uart_irq_tx_ready(ctx->dev)) {
mb_cb_handler_tx(ctx);
}
}
}
static void mb_rx_handler(struct k_work *item)
{
struct modbus_context *ctx =
CONTAINER_OF(item, struct modbus_context, server_work);
if (ctx == NULL) {
LOG_ERR("Where is my pointer?");
return;
}
mb_rx_disable(ctx);
switch (ctx->mode) {
case MODBUS_MODE_RTU:
ctx->rx_frame_err = mb_rx_rtu_frame(ctx);
break;
case MODBUS_MODE_ASCII:
if (IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
ctx->rx_frame_err = mb_rx_ascii_frame(ctx);
break;
}
default:
LOG_ERR("Unknown MODBUS mode");
return;
}
ctx->uart_buf_ctr = 0;
ctx->uart_buf_ptr = &ctx->uart_buf[0];
if (ctx->client == true) {
k_sem_give(&ctx->client_wait_sem);
} else if (IS_ENABLED(CONFIG_MODBUS_SERVER)) {
if (mbs_rx_handler(ctx) == false) {
/* Server does not send response, re-enable RX */
mb_rx_enable(ctx);
}
}
}
/* This function is called when the RTU framing timer expires. */
static void mb_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 mb_configure_uart(struct modbus_context *ctx,
uint32_t baudrate,
enum uart_config_parity parity)
{
const uint32_t if_delay_max = 3500000;
const uint32_t numof_bits = 11;
struct uart_config uart_cfg;
ctx->dev = device_get_binding(ctx->dev_name);
if (ctx->dev == NULL) {
LOG_ERR("Failed to get UART device %s",
log_strdup(ctx->dev_name));
return -ENODEV;
}
uart_cfg.baudrate = baudrate,
uart_cfg.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 (parity) {
case UART_CFG_PARITY_ODD:
case UART_CFG_PARITY_EVEN:
uart_cfg.parity = 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 = parity;
uart_cfg.stop_bits = UART_CFG_STOP_BITS_2;
break;
default:
return -EINVAL;
}
if (uart_configure(ctx->dev, &uart_cfg) != 0) {
LOG_ERR("Failed to configure UART");
return -EINVAL;
}
uart_irq_callback_user_data_set(ctx->dev, mb_uart_cb_handler, ctx);
mb_rx_enable(ctx);
if (baudrate <= 38400) {
ctx->rtu_timeout = (numof_bits * if_delay_max) / baudrate;
} else {
ctx->rtu_timeout = (numof_bits * if_delay_max) / 38400;
}
LOG_INF("RTU timeout %u us", ctx->rtu_timeout);
return 0;
}
struct modbus_context *mb_get_context(const uint8_t iface)
{
struct modbus_context *ctx;
@ -586,36 +121,6 @@ struct modbus_context *mb_get_context(const uint8_t iface)
return ctx;
}
static int mb_configure_gpio(struct modbus_context *ctx)
{
if (ctx->de != NULL) {
ctx->de->dev = device_get_binding(ctx->de->name);
if (ctx->de->dev == NULL) {
return -ENODEV;
}
if (gpio_pin_configure(ctx->de->dev, ctx->de->pin,
GPIO_OUTPUT_INACTIVE | ctx->de->flags)) {
return -EIO;
}
}
if (ctx->re != NULL) {
ctx->re->dev = device_get_binding(ctx->re->name);
if (ctx->re->dev == NULL) {
return -ENODEV;
}
if (gpio_pin_configure(ctx->re->dev, ctx->re->pin,
GPIO_OUTPUT_INACTIVE | ctx->re->flags)) {
return -EIO;
}
}
return 0;
}
static struct modbus_context *mb_cfg_iface(const uint8_t iface,
const uint8_t node_addr,
const uint32_t baud,
@ -648,7 +153,6 @@ static struct modbus_context *mb_cfg_iface(const uint8_t iface,
ctx->rxwait_to = rx_timeout;
ctx->node_addr = node_addr;
ctx->client = client;
ctx->mode = ascii_mode ? MODBUS_MODE_ASCII : MODBUS_MODE_RTU;
ctx->mbs_user_cb = NULL;
k_mutex_init(&ctx->iface_lock);
@ -656,23 +160,17 @@ static struct modbus_context *mb_cfg_iface(const uint8_t iface,
ctx->uart_buf_ptr = &ctx->uart_buf[0];
k_sem_init(&ctx->client_wait_sem, 0, 1);
k_work_init(&ctx->server_work, mb_rx_handler);
k_work_init(&ctx->server_work, modbus_rx_handler);
if (IS_ENABLED(CONFIG_MODBUS_FC08_DIAGNOSTIC)) {
mbs_reset_statistics(ctx);
}
if (mb_configure_gpio(ctx) != 0) {
if (modbus_serial_init(ctx, baud, parity, ascii_mode) != 0) {
LOG_ERR("Failed to init MODBUS over serial line");
return NULL;
}
if (mb_configure_uart(ctx, baud, parity) != 0) {
LOG_ERR("Failed to configure UART");
return NULL;
}
k_timer_init(&ctx->rtu_timer, mb_rtu_tmr_handler, NULL);
k_timer_user_data_set(&ctx->rtu_timer, ctx);
LOG_DBG("Modbus interface %s initialized", ctx->iface_name);
return ctx;
@ -751,10 +249,7 @@ int modbus_disable(const uint8_t iface)
ctx = &mb_ctx_tbl[iface];
mb_tx_disable(ctx);
mb_rx_disable(ctx);
k_timer_stop(&ctx->rtu_timer);
modbus_serial_disable(ctx);
ctx->rxwait_to = 0;
ctx->node_addr = 0;
ctx->mode = MODBUS_MODE_RTU;

13
subsys/modbus/modbus_internal.h
View file

@ -135,7 +135,7 @@ struct modbus_context {
/* Number of bytes received or to send */
uint16_t uart_buf_ctr;
/* Records error from frame reception, e.g. CRC error */
uint16_t rx_frame_err;
int rx_frame_err;
#ifdef CONFIG_MODBUS_FC08_DIAGNOSTIC
uint16_t mbs_msg_ctr;
@ -152,10 +152,19 @@ struct modbus_context {
};
struct modbus_context *mb_get_context(const uint8_t iface);
int mb_rx_frame(struct modbus_context *ctx);
void mb_tx_frame(struct modbus_context *ctx);
bool mbs_rx_handler(struct modbus_context *ctx);
void mbs_reset_statistics(struct modbus_context *pch);
void modbus_serial_rx_disable(struct modbus_context *ctx);
void modbus_serial_rx_enable(struct modbus_context *ctx);
int modbus_serial_rx_frame(struct modbus_context *ctx);
int modbus_serial_tx_frame(struct modbus_context *ctx);
int modbus_serial_init(struct modbus_context *ctx,
uint32_t baudrate,
enum uart_config_parity parity,
const bool ascii_mode);
void modbus_serial_disable(struct modbus_context *ctx);
#endif /* ZEPHYR_INCLUDE_MODBUS_INTERNAL_H_ */

581
subsys/modbus/modbus_serial.c Normal file
View file

@ -0,0 +1,581 @@
/*
* 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 <logging/log.h>
LOG_MODULE_REGISTER(modbus_serial, CONFIG_MODBUS_LOG_LEVEL);
#include <kernel.h>
#include <string.h>
#include <sys/byteorder.h>
#include <modbus_internal.h>
static void modbus_serial_tx_on(struct modbus_context *ctx)
{
if (ctx->de != NULL) {
gpio_pin_set(ctx->de->dev, ctx->de->pin, 1);
}
uart_irq_tx_enable(ctx->dev);
}
static void modbus_serial_tx_off(struct modbus_context *ctx)
{
uart_irq_tx_disable(ctx->dev);
if (ctx->de != NULL) {
gpio_pin_set(ctx->de->dev, ctx->de->pin, 0);
}
}
static void modbus_serial_rx_on(struct modbus_context *ctx)
{
if (ctx->re != NULL) {
gpio_pin_set(ctx->re->dev, ctx->re->pin, 1);
}
uart_irq_rx_enable(ctx->dev);
}
static void modbus_serial_rx_off(struct modbus_context *ctx)
{
uart_irq_rx_disable(ctx->dev);
if (ctx->re != NULL) {
gpio_pin_set(ctx->re->dev, ctx->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_frame(struct modbus_context *ctx)
{
uint8_t *pmsg;
uint8_t *prx_data;
uint16_t rx_size;
uint8_t frame_lrc;
uint8_t calc_lrc;
rx_size = ctx->uart_buf_ctr;
prx_data = &ctx->rx_frame.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 ((ctx->uart_buf[0] != MODBUS_ASCII_START_FRAME_CHAR) ||
(ctx->uart_buf[rx_size - 2] != MODBUS_ASCII_END_FRAME_CHAR1) ||
(ctx->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 = &ctx->uart_buf[1];
hex2bin(pmsg, 2, &ctx->rx_frame.addr, 1);
pmsg += 2;
rx_size -= 2;
hex2bin(pmsg, 2, &ctx->rx_frame.fc, 1);
pmsg += 2;
rx_size -= 2;
/* Get the data from the message */
ctx->rx_frame.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_frame.length++;
}
/* Extract the message's LRC */
hex2bin(pmsg, 2, &frame_lrc, 1);
ctx->rx_frame.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(&ctx->uart_buf[1],
(ctx->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_frame(struct modbus_context *ctx)
{
uint16_t tx_bytes = 0;
uint8_t lrc;
uint8_t *pbuf;
/* Place the start-of-frame character into output buffer */
ctx->uart_buf[0] = MODBUS_ASCII_START_FRAME_CHAR;
tx_bytes = 1;
pbuf = &ctx->uart_buf[1];
pbuf = modbus_ascii_bin2hex(ctx->tx_frame.addr, pbuf);
tx_bytes += 2;
pbuf = modbus_ascii_bin2hex(ctx->tx_frame.fc, pbuf);
tx_bytes += 2;
for (int i = 0; i < ctx->tx_frame.length; i++) {
pbuf = modbus_ascii_bin2hex(ctx->tx_frame.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(&ctx->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 */
ctx->uart_buf_ctr = tx_bytes;
ctx->uart_buf_ptr = &ctx->uart_buf[0];
LOG_DBG("Start frame transmission");
modbus_serial_rx_off(ctx);
modbus_serial_tx_on(ctx);
}
#else
static int modbus_ascii_rx_frame(struct modbus_context *ctx)
{
return 0;
}
static void modbus_ascii_tx_frame(struct modbus_context *ctx)
{
}
#endif
static uint16_t modbus_rtu_crc16(uint8_t *src, size_t length)
{
uint16_t crc = 0xFFFF;
uint8_t shiftctr;
bool flag;
uint8_t *pblock = src;
while (length > 0) {
length--;
crc ^= (uint16_t)*pblock++;
shiftctr = 8;
do {
/* Determine if the shift out of rightmost bit is 1 */
flag = (crc & 0x0001) ? true : false;
/* Shift CRC to the right one bit. */
crc >>= 1;
/*
* If bit shifted out of rightmost bit was a 1
* exclusive OR the CRC with the generating polynomial.
*/
if (flag == true) {
crc ^= MODBUS_CRC16_POLY;
}
shiftctr--;
} while (shiftctr > 0);
}
return crc;
}
/* Copy Modbus RTU frame and check if the CRC is valid. */
static int modbus_rtu_rx_frame(struct modbus_context *ctx)
{
uint16_t calc_crc;
uint16_t crc_idx;
uint8_t *data_ptr;
/* Is the message long enough? */
if ((ctx->uart_buf_ctr < MODBUS_RTU_MIN_MSG_SIZE) ||
(ctx->uart_buf_ctr > CONFIG_MODBUS_BUFFER_SIZE)) {
LOG_WRN("Frame length error");
return -EMSGSIZE;
}
ctx->rx_frame.addr = ctx->uart_buf[0];
ctx->rx_frame.fc = ctx->uart_buf[1];
data_ptr = &ctx->uart_buf[2];
/* Payload length without node address, function code, and CRC */
ctx->rx_frame.length = ctx->uart_buf_ctr - 4;
/* CRC index */
crc_idx = ctx->uart_buf_ctr - sizeof(uint16_t);
memcpy(ctx->rx_frame.data, data_ptr, ctx->rx_frame.length);
ctx->rx_frame.crc = sys_get_le16(&ctx->uart_buf[crc_idx]);
/* Calculate CRC over address, function code, and payload */
calc_crc = modbus_rtu_crc16(&ctx->uart_buf[0],
ctx->uart_buf_ctr - sizeof(ctx->rx_frame.crc));
if (ctx->rx_frame.crc != calc_crc) {
LOG_WRN("Calculated CRC does not match received CRC");
return -EIO;
}
return 0;
}
static void rtu_tx_frame(struct modbus_context *ctx)
{
uint16_t tx_bytes = 0;
uint8_t *data_ptr;
ctx->uart_buf[0] = ctx->tx_frame.addr;
ctx->uart_buf[1] = ctx->tx_frame.fc;
tx_bytes = 2 + ctx->tx_frame.length;
data_ptr = &ctx->uart_buf[2];
memcpy(data_ptr, ctx->tx_frame.data, ctx->tx_frame.length);
ctx->tx_frame.crc = modbus_rtu_crc16(&ctx->uart_buf[0],
ctx->tx_frame.length + 2);
sys_put_le16(ctx->tx_frame.crc,
&ctx->uart_buf[ctx->tx_frame.length + 2]);
tx_bytes += 2;
ctx->uart_buf_ctr = tx_bytes;
ctx->uart_buf_ptr = &ctx->uart_buf[0];
LOG_HEXDUMP_DBG(ctx->uart_buf, ctx->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)
{
if ((ctx->mode == MODBUS_MODE_ASCII) &&
IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
uint8_t c;
if (uart_fifo_read(ctx->dev, &c, 1) != 1) {
LOG_ERR("Failed to read UART");
return;
}
if (c == MODBUS_ASCII_START_FRAME_CHAR) {
/* Restart a new frame */
ctx->uart_buf_ptr = &ctx->uart_buf[0];
ctx->uart_buf_ctr = 0;
}
if (ctx->uart_buf_ctr < CONFIG_MODBUS_BUFFER_SIZE) {
*ctx->uart_buf_ptr++ = c;
ctx->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(&ctx->rtu_timer,
K_USEC(ctx->rtu_timeout), K_NO_WAIT);
n = uart_fifo_read(ctx->dev, ctx->uart_buf_ptr,
(CONFIG_MODBUS_BUFFER_SIZE -
ctx->uart_buf_ctr));
ctx->uart_buf_ptr += n;
ctx->uart_buf_ctr += n;
}
}
static void cb_handler_tx(struct modbus_context *ctx)
{
int n;
if (ctx->uart_buf_ctr > 0) {
n = uart_fifo_fill(ctx->dev, ctx->uart_buf_ptr,
ctx->uart_buf_ctr);
ctx->uart_buf_ctr -= n;
ctx->uart_buf_ptr += n;
} else {
/* Disable transmission */
ctx->uart_buf_ptr = &ctx->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;
if (ctx == NULL) {
LOG_ERR("Modbus hardware is not properly initialized");
return;
}
while (uart_irq_update(ctx->dev) && uart_irq_is_pending(ctx->dev)) {
if (uart_irq_rx_ready(ctx->dev)) {
cb_handler_rx(ctx);
}
if (uart_irq_tx_ready(ctx->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)
{
if (ctx->de != NULL) {
ctx->de->dev = device_get_binding(ctx->de->name);
if (ctx->de->dev == NULL) {
return -ENODEV;
}
if (gpio_pin_configure(ctx->de->dev, ctx->de->pin,
GPIO_OUTPUT_INACTIVE | ctx->de->flags)) {
return -EIO;
}
}
if (ctx->re != NULL) {
ctx->re->dev = device_get_binding(ctx->re->name);
if (ctx->re->dev == NULL) {
return -ENODEV;
}
if (gpio_pin_configure(ctx->re->dev, ctx->re->pin,
GPIO_OUTPUT_INACTIVE | ctx->re->flags)) {
return -EIO;
}
}
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_frame(struct modbus_context *ctx)
{
int rc = 0;
switch (ctx->mode) {
case MODBUS_MODE_RTU:
rc = modbus_rtu_rx_frame(ctx);
break;
case MODBUS_MODE_ASCII:
if (!IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
return -ENOTSUP;
}
rc = modbus_ascii_rx_frame(ctx);
break;
default:
LOG_ERR("Unsupported MODBUS mode");
return -ENOTSUP;
}
ctx->uart_buf_ctr = 0;
ctx->uart_buf_ptr = &ctx->uart_buf[0];
return rc;
}
int modbus_serial_tx_frame(struct modbus_context *ctx)
{
switch (ctx->mode) {
case MODBUS_MODE_RTU:
rtu_tx_frame(ctx);
return 0;
case MODBUS_MODE_ASCII:
if (IS_ENABLED(CONFIG_MODBUS_ASCII_MODE)) {
modbus_ascii_tx_frame(ctx);
return 0;
}
default:
break;
}
return -ENOTSUP;
}
int modbus_serial_init(struct modbus_context *ctx,
uint32_t baudrate,
enum uart_config_parity parity,
const bool ascii_mode)
{
const uint32_t if_delay_max = 3500000;
const uint32_t numof_bits = 11;
struct uart_config uart_cfg;
ctx->dev = device_get_binding(ctx->dev_name);
if (ctx->dev == NULL) {
LOG_ERR("Failed to get UART device %s",
log_strdup(ctx->dev_name));
return -ENODEV;
}
uart_cfg.baudrate = baudrate,
uart_cfg.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 (parity) {
case UART_CFG_PARITY_ODD:
case UART_CFG_PARITY_EVEN:
uart_cfg.parity = 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 = parity;
uart_cfg.stop_bits = UART_CFG_STOP_BITS_2;
break;
default:
return -EINVAL;
}
if (uart_configure(ctx->dev, &uart_cfg) != 0) {
LOG_ERR("Failed to configure UART");
return -EINVAL;
}
if (baudrate <= 38400) {
ctx->rtu_timeout = (numof_bits * if_delay_max) / baudrate;
} else {
ctx->rtu_timeout = (numof_bits * if_delay_max) / 38400;
}
if (configure_gpio(ctx) != 0) {
return -EIO;
}
uart_irq_callback_user_data_set(ctx->dev, uart_cb_handler, ctx);
modbus_serial_rx_on(ctx);
ctx->mode = ascii_mode ? MODBUS_MODE_ASCII : MODBUS_MODE_RTU;
k_timer_init(&ctx->rtu_timer, rtu_tmr_handler, NULL);
k_timer_user_data_set(&ctx->rtu_timer, ctx);
LOG_INF("RTU timeout %u us", ctx->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->rtu_timer);
}