From f2eecc33f7b5d27cf6244fce84cadb606e69f920 Mon Sep 17 00:00:00 2001 From: Phil-Engljaehringer Date: Fri, 12 Jun 2026 18:27:26 +0200 Subject: [PATCH] feat(drivers): implemented serial passthrough (#27605) * feat: implemented serial passthrough * fix: used make format * fix: changed function order to match other drivers * fix: moved passthrough from systemcmds to drivers * fix: renamed BITBANG_TIMER to UART_BITBANG_TIMER * fix: used make format * feat: added PASSTHRU_EN guard to start of dshot&pwm_out * fix: made changing ESC channels more stable * fix: adjusted naming of guards * fix: changed include guard of bitbang * fix: removed unused variable SER_PASS_BAUD * fix: adjusted comments * fix: adjusted print_usage() to match other drivers * fix: remove bitbang_write_byte from public API and some buffer guard * fix: added Serialpassthrough&Bitbang to exclude list of allyesconfig.py * fix: added missing flag to print_usage() --- ROMFS/px4fmu_common/init.d/rcS | 9 +- Tools/kconfig/allyesconfig.py | 3 + boards/auterion/fmu-v6s/default.px4board | 3 + .../fmu-v6s/nuttx-config/nsh/defconfig | 1 + boards/auterion/fmu-v6x/default.px4board | 3 + .../fmu-v6x/nuttx-config/nsh/defconfig | 1 + .../stm32_common/bitbang_uart/CMakeLists.txt | 37 + .../bitbang_uart/bitbang_uart.cpp | 534 +++++++++++++ .../nuttx/src/px4/stm/stm32f7/CMakeLists.txt | 4 + .../nuttx/src/px4/stm/stm32h7/CMakeLists.txt | 4 + src/drivers/drv_bitbang_uart.h | 95 +++ src/drivers/serialpassthrough/CMakeLists.txt | 47 ++ src/drivers/serialpassthrough/Kconfig | 30 + src/drivers/serialpassthrough/module.yaml | 15 + .../serialpassthrough/serialpassthrough.cpp | 729 ++++++++++++++++++ .../serialpassthrough/serialpassthrough.hpp | 164 ++++ src/modules/mavlink/CMakeLists.txt | 4 + src/modules/mavlink/mavlink_main.cpp | 38 + src/modules/mavlink/mavlink_main.h | 2 + src/modules/mavlink/mavlink_receiver.cpp | 35 +- 20 files changed, 1752 insertions(+), 6 deletions(-) create mode 100644 platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/CMakeLists.txt create mode 100644 platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/bitbang_uart.cpp create mode 100644 src/drivers/drv_bitbang_uart.h create mode 100644 src/drivers/serialpassthrough/CMakeLists.txt create mode 100644 src/drivers/serialpassthrough/Kconfig create mode 100644 src/drivers/serialpassthrough/module.yaml create mode 100644 src/drivers/serialpassthrough/serialpassthrough.cpp create mode 100644 src/drivers/serialpassthrough/serialpassthrough.hpp diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS index 8e44fecca3d..2d655e1208f 100644 --- a/ROMFS/px4fmu_common/init.d/rcS +++ b/ROMFS/px4fmu_common/init.d/rcS @@ -539,8 +539,13 @@ else else commander start - dshot start - pwm_out start + if param compare -s PASSTHRU_EN 0 + then + dshot start + pwm_out start + else + param set PASSTHRU_EN 0 + fi fi # diff --git a/Tools/kconfig/allyesconfig.py b/Tools/kconfig/allyesconfig.py index bd3fbe4f98a..6f732e8e196 100644 --- a/Tools/kconfig/allyesconfig.py +++ b/Tools/kconfig/allyesconfig.py @@ -54,6 +54,8 @@ exception_list = [ 'MODULES_MUORB_APPS', # Weird QURT/Posix package doesn't work on x86 px4 sitl 'MODULES_SIMULATION_SIMULATOR_SIH', # Causes compile errors 'MODULES_SPACECRAFT', # Clashes with Control Allocation (mom's spaghetti code) + 'DRIVERS_SERIALPASSTHROUGH', # Requires board-specific UART config and NuttX + 'SERIALPASSTHROUGH_BITBANG', # Requires STM32 timer and GPIO config ] exception_list_sitl = [ @@ -110,6 +112,7 @@ exception_list_sitl = [ 'SYSTEMCMDS_USB_CONNECTED', # Not supported in SITL 'SYSTEMCMDS_MFT_CFG', # Not supported in SITL 'MODULES_SPACECRAFT', # Clashes with Control Allocation (mom's spaghetti code) + 'DRIVERS_SERIALPASSTHROUGH', # Not supported in SITL ] def main(): diff --git a/boards/auterion/fmu-v6s/default.px4board b/boards/auterion/fmu-v6s/default.px4board index 514794a5213..deec09bcdab 100644 --- a/boards/auterion/fmu-v6s/default.px4board +++ b/boards/auterion/fmu-v6s/default.px4board @@ -1,5 +1,6 @@ CONFIG_BOARD_TOOLCHAIN="arm-none-eabi" CONFIG_BOARD_ARCHITECTURE="cortex-m7" +CONFIG_ARCH_CHIP_STM32H7=y CONFIG_BOARD_ETHERNET=y CONFIG_BOARD_SERIAL_GPS1="/dev/ttyS6" CONFIG_BOARD_SERIAL_TEL1="/dev/ttyS0" @@ -95,4 +96,6 @@ CONFIG_SYSTEMCMDS_TOPIC_LISTENER=y CONFIG_SYSTEMCMDS_UORB=y CONFIG_SYSTEMCMDS_VER=y CONFIG_SYSTEMCMDS_WORK_QUEUE=y +CONFIG_DRIVERS_SERIALPASSTHROUGH=y +CONFIG_SERIALPASSTHROUGH_BITBANG=y CONFIG_WQ_TTY_STACKSIZE=2500 diff --git a/boards/auterion/fmu-v6s/nuttx-config/nsh/defconfig b/boards/auterion/fmu-v6s/nuttx-config/nsh/defconfig index 0ab86df4dda..ee6bb65b664 100644 --- a/boards/auterion/fmu-v6s/nuttx-config/nsh/defconfig +++ b/boards/auterion/fmu-v6s/nuttx-config/nsh/defconfig @@ -244,6 +244,7 @@ CONFIG_STM32H7_TIM3=y CONFIG_STM32H7_TIM4=y CONFIG_STM32H7_TIM5=y CONFIG_STM32H7_TIM8=y +CONFIG_STM32H7_TIM13=y CONFIG_STM32H7_UART4=y CONFIG_STM32H7_UART5=y CONFIG_STM32H7_UART7=y diff --git a/boards/auterion/fmu-v6x/default.px4board b/boards/auterion/fmu-v6x/default.px4board index 4fcba9a10a2..50cf4cacca9 100644 --- a/boards/auterion/fmu-v6x/default.px4board +++ b/boards/auterion/fmu-v6x/default.px4board @@ -1,5 +1,6 @@ CONFIG_BOARD_TOOLCHAIN="arm-none-eabi" CONFIG_BOARD_ARCHITECTURE="cortex-m7" +CONFIG_ARCH_CHIP_STM32H7=y CONFIG_BOARD_ETHERNET=y CONFIG_BOARD_SERIAL_GPS1="/dev/ttyS0" CONFIG_BOARD_SERIAL_GPS2="/dev/ttyS7" @@ -99,3 +100,5 @@ CONFIG_SYSTEMCMDS_TUNE_CONTROL=y CONFIG_SYSTEMCMDS_UORB=y CONFIG_SYSTEMCMDS_VER=y CONFIG_SYSTEMCMDS_WORK_QUEUE=y +CONFIG_DRIVERS_SERIALPASSTHROUGH=y +CONFIG_SERIALPASSTHROUGH_BITBANG=y diff --git a/boards/auterion/fmu-v6x/nuttx-config/nsh/defconfig b/boards/auterion/fmu-v6x/nuttx-config/nsh/defconfig index 6070e6696ee..c514e8be4fa 100644 --- a/boards/auterion/fmu-v6x/nuttx-config/nsh/defconfig +++ b/boards/auterion/fmu-v6x/nuttx-config/nsh/defconfig @@ -257,6 +257,7 @@ CONFIG_STM32H7_TIM12=y CONFIG_STM32H7_TIM1=y CONFIG_STM32H7_TIM4=y CONFIG_STM32H7_TIM5=y +CONFIG_STM32H7_TIM13=y CONFIG_STM32H7_UART4=y CONFIG_STM32H7_UART5=y CONFIG_STM32H7_UART7=y diff --git a/platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/CMakeLists.txt b/platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/CMakeLists.txt new file mode 100644 index 00000000000..f5d3d72b059 --- /dev/null +++ b/platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/CMakeLists.txt @@ -0,0 +1,37 @@ +############################################################################ +# +# Copyright (c) 2026 PX4 Development Team. All rights reserved. +# +# 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. +# 3. Neither the name PX4 nor the names of its contributors may be +# used to endorse or promote products derived from this software +# without specific prior written permission. +# +# 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. +# +############################################################################ + +px4_add_library(arch_bitbang_uart + bitbang_uart.cpp +) +target_compile_options(arch_bitbang_uart PRIVATE ${MAX_CUSTOM_OPT_LEVEL}) diff --git a/platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/bitbang_uart.cpp b/platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/bitbang_uart.cpp new file mode 100644 index 00000000000..a783111c94b --- /dev/null +++ b/platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/bitbang_uart.cpp @@ -0,0 +1,534 @@ +/**************************************************************************** + * + * Copyright (c) 2026 PX4 Development Team. All rights reserved. + * + * 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. + * 3. Neither the name PX4 nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * 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. + * + ****************************************************************************/ + +/** + * @file bitbang_uart.cpp + * + * Simple bit-bang UART using timer for periodic interrupts and direct GPIO control. + * Note: due to interrupt latency and CPU overhead, reliable operation is only + * guaranteed up to 19200 baud. Higher baud rates are not supported. + */ + +#include + +#include +#include +#include +#include + +#include +#include + +#include +#include +#include +#include + +#include +#include + +#if !defined(CONFIG_ARCH_CHIP_STM32F7) && !defined(CONFIG_ARCH_CHIP_STM32H7) +# error "Not supported on this MCU, requires STM32 based MCU" +#endif + +// Timer interrupt sources +#define GTIM_SR_UIF (1 << 0) +#define GTIM_DIER_UIE (1 << 0) + +// UART frame format: 8N1 (8 data bits, no parity, 1 stop bit) +#define MAX_UART_CHANNELS 8 +#define UART_TOTAL_BITS 10 // Start + 8 data + Stop +#define TX_BUFFER_SIZE 512 // Circular buffer for queued bytes +#define RX_BUFFER_SIZE 512 // Circular buffer for received bytes + +typedef struct { + // Configuration + uint8_t channel; + uint32_t gpio_pin; + uint32_t bit_time_ticks; + bool initialized; + bool single_wire; // true = half-duplex (TX and RX share one GPIO); false = full-duplex (not yet implemented) + struct stm32_tim_dev_s *timer; + + // TX state + px4::atomic_bool tx_busy; + uint16_t tx_shift_reg; + uint8_t tx_bit_count; + + // TX buffer (circular queue) + uint8_t tx_buffer[TX_BUFFER_SIZE]; + volatile uint16_t tx_head; // Write position + volatile uint16_t tx_tail; // Read position + + // RX state + volatile bool rx_in_progress; + volatile uint16_t rx_shift_reg; + volatile uint8_t rx_bit_count; + + // RX buffer (circular queue) + uint8_t rx_buffer[RX_BUFFER_SIZE]; + volatile uint16_t rx_head; // Write position (interrupt) + volatile uint16_t rx_tail; // Read position (user) + +} bitbang_uart_t; + +// Single UART instance (only one channel active at a time) +static bitbang_uart_t uart = {}; + +// Forward declarations +static int gpio_rx_interrupt_callback(int irq, void *context, void *arg); + +// Helper function to enable/disable GPIO interrupt for RX +static int set_gpio_interrupt(bool enable) +{ + if (enable) { + // Stop timer + STM32_TIM_SETMODE(uart.timer, STM32_TIM_MODE_DISABLED); + + px4_arch_gpiowrite(uart.gpio_pin, true); + // Configure new GPIO as input with pullup for RX + px4_arch_configgpio(PX4_MAKE_GPIO_INPUT(uart.gpio_pin)); + + // Enable falling edge interrupt for start bit detection + return px4_arch_gpiosetevent(PX4_MAKE_GPIO_EXTI(uart.gpio_pin), false, true, true, &gpio_rx_interrupt_callback, &uart); + + } else { + // Disable interrupt + return px4_arch_gpiosetevent(PX4_MAKE_GPIO_EXTI(uart.gpio_pin), false, false, false, nullptr, nullptr); + } +} + +// TIM update interrupt handler - fires every bit period +static int timer_update_isr(int, void *, void *) +{ + // Clear update interrupt flag + STM32_TIM_ACKINT(uart.timer, GTIM_SR_UIF); + + // Handle TX + if (uart.tx_busy.load()) { + // Get current bit value from shift register + bool bit_value = (uart.tx_shift_reg >> uart.tx_bit_count) & 0x01; + + // Set GPIO directly + px4_arch_gpiowrite(uart.gpio_pin, bit_value); + + uart.tx_bit_count++; + + // Check if transmission complete + if (uart.tx_bit_count >= UART_TOTAL_BITS) { + // Check if there's more data in the buffer + if (uart.tx_tail != uart.tx_head) { + // Start next byte immediately without returning to scheduler + uint8_t next_byte = uart.tx_buffer[uart.tx_tail]; + uart.tx_tail = (uart.tx_tail + 1) % TX_BUFFER_SIZE; + + // Build frame for next byte + uart.tx_shift_reg = 0; + uart.tx_shift_reg |= (0 << 0); // Start bit + uart.tx_shift_reg |= (next_byte << 1); // Data bits + uart.tx_shift_reg |= (1 << 9); // Stop bit + uart.tx_bit_count = 0; + // tx_busy stays true + + } else { + // No more data, stop transmitting + uart.tx_busy.store(false); + + // Clear RX buffer + uart.rx_tail = uart.rx_head; + + // Re-enable RX interrupt after transmission + set_gpio_interrupt(true); + } + } + } + + // Handle RX + else if (uart.rx_in_progress) { + // Sample current pin state + bool bit_value = px4_arch_gpioread(uart.gpio_pin); + + // Accumulate all bits as seen on the wire + if (bit_value) { + uart.rx_shift_reg |= (1 << uart.rx_bit_count); + } + + uart.rx_bit_count++; + + // Check if we've received the complete frame (start + 8 data + stop) + if (uart.rx_bit_count >= UART_TOTAL_BITS) { + // Extract data bits (bits 1-8) and reverse them (LSB-first on wire -> MSB-first in byte) + const uint8_t received_byte = (uart.rx_shift_reg >> 1) & 0xFF; // Skip start bit, get bits 1-8 + + uart.rx_in_progress = false; + + // Store byte in RX buffer + uint16_t next_head = (uart.rx_head + 1) % RX_BUFFER_SIZE; + + if (next_head != uart.rx_tail) { + // Buffer not full, store byte + uart.rx_buffer[uart.rx_head] = received_byte; + uart.rx_head = next_head; + } + + // If buffer full, drop byte (overrun) + + // Re-enable start bit detection + set_gpio_interrupt(true); + } + } + + return OK; +} + +// GPIO interrupt handler for RX - detects start bit only +static int gpio_rx_interrupt_callback(int irq, void *context, void *arg) +{ + // Start bit detection (high to low transition) + if (!uart.rx_in_progress) { + // Disable further start bit detection until this byte completes + set_gpio_interrupt(false); + + uart.rx_in_progress = true; + uart.rx_shift_reg = 0; + uart.rx_bit_count = 0; + + // Configure timer to sample in middle of each bit period + STM32_TIM_SETCOUNTER(uart.timer, uart.bit_time_ticks / 2); + + // Clear any pending update interrupt + STM32_TIM_ACKINT(uart.timer, GTIM_SR_UIF); + + // Start timer for RX sampling + STM32_TIM_SETMODE(uart.timer, STM32_TIM_MODE_UP); + } + + return OK; +} + +static bool tim_initialized = false; +// Shared timer initialization (call once) +static int bitbang_uart_init_timer(uint32_t baudrate) +{ + if (tim_initialized) { + return 0; // Already initialized + } + + uart.bit_time_ticks = 1000000 / baudrate; // Assume 1MHz timer + + // Initialize timer using NuttX API + uart.timer = stm32_tim_init(CONFIG_UART_BITBANG_TIMER); + + if (uart.timer == nullptr) { + PX4_ERR("Failed to initialize timer %d", CONFIG_UART_BITBANG_TIMER); + return -1; + } + + // Set timer to 1MHz clock + STM32_TIM_SETCLOCK(uart.timer, 1000000); + + // Set period for baud rate + STM32_TIM_SETPERIOD(uart.timer, uart.bit_time_ticks - 1); + + // Attach interrupt handler for update event + STM32_TIM_SETISR(uart.timer, timer_update_isr, nullptr, 0); + + // Enable update interrupt + STM32_TIM_ENABLEINT(uart.timer, GTIM_DIER_UIE); + + tim_initialized = true; + + return 0; +} + +int bitbang_uart_init(uint32_t baudrate, bool single_wire) +{ + if (!single_wire) { + PX4_ERR("bitbang_uart: full-duplex (dual-wire) mode is not yet implemented"); + return -ENOSYS; + } + + // Initialize timer once (shared across all channels) + int ret = bitbang_uart_init_timer(baudrate); + + if (ret != 0) { + return ret; + } + + // Initialize structure (no channel yet) + uart.channel = 0xFF; // Mark as no channel selected + uart.initialized = true; + uart.single_wire = single_wire; + + // Set all ESC signal pins (channels 0-3) to high (idle state) + for (uint8_t ch = 0; ch < MAX_UART_CHANNELS; ch++) { + uint32_t gpio_pin = io_timer_channel_get_gpio_output(ch); + PX4_DEBUG("bitbang_uart_init: channel %u gpio_pin=0x%08lx", ch, (unsigned long)gpio_pin); + + if (gpio_pin == 0) { + PX4_WARN("bitbang_uart_init: channel %u has no GPIO pin (not in timer_config?)", ch); + continue; + } + + px4_arch_configgpio(PX4_MAKE_GPIO_OUTPUT_SET(gpio_pin)); + } + + return 0; +} + +int bitbang_uart_switch_channel(uint8_t channel) +{ + if (channel >= MAX_UART_CHANNELS) { + return -EINVAL; + } + + if (!uart.initialized) { + return -EINVAL; + } + + // If already on this channel, nothing to do + if (uart.channel == channel) { + return 0; + } + + // Disable previous channel's RX interrupt if a channel was active + if (uart.channel != 0xFF) { + set_gpio_interrupt(false); + + // Wait for any ongoing TX to complete + while (uart.tx_busy.load()) { + px4_usleep(10); + } + + // Stop the timer and clear any pending interrupt so a remaining RX + // transfer cannot fire and overwrite the buffer state + STM32_TIM_SETMODE(uart.timer, STM32_TIM_MODE_DISABLED); + STM32_TIM_ACKINT(uart.timer, GTIM_SR_UIF); + } + + // Reset TX/RX buffers to avoid stale data from the previous channel + uart.tx_head = 0; + uart.tx_tail = 0; + uart.rx_head = 0; + uart.rx_tail = 0; + uart.rx_in_progress = false; + + // Update to new channel + uart.channel = channel; + uart.gpio_pin = io_timer_channel_get_gpio_output(channel); + PX4_DEBUG("bitbang_uart_switch_channel: channel %u gpio_pin=0x%08lx", channel, (unsigned long)uart.gpio_pin); + + if (uart.gpio_pin == 0) { + PX4_ERR("bitbang_uart_switch_channel: channel %u has no GPIO pin", channel); + return -EINVAL; + } + + // Set up interrupt on falling edge for start bit detection + int ret = set_gpio_interrupt(true); + + if (ret != PX4_OK) { + PX4_ERR("Failed to setup GPIO interrupt for channel %d", channel); + return ret; + } + + PX4_DEBUG("Switched to channel %d", channel); + + return 0; +} + +int bitbang_uart_deinit() +{ + if (!uart.initialized) { + return -EINVAL; + } + + // Disable RX interrupt if a channel is active + if (uart.channel != 0xFF) { + set_gpio_interrupt(false); + } + + // Wait for TX to complete + while (uart.tx_busy.load()) { + px4_usleep(100); + } + + // Disable timer interrupts + STM32_TIM_DISABLEINT(uart.timer, GTIM_DIER_UIE); + + // Detach interrupt handler + STM32_TIM_SETISR(uart.timer, nullptr, nullptr, 0); + + // Stop timer + STM32_TIM_SETMODE(uart.timer, STM32_TIM_MODE_DISABLED); + + // Deinitialize timer + stm32_tim_deinit(uart.timer); + uart.timer = nullptr; + + uart.initialized = false; + tim_initialized = false; + uart.channel = 0xFF; + + return 0; +} + +static int bitbang_uart_write_byte(uint8_t channel, uint8_t byte) +{ + if (!uart.initialized) { + return -EINVAL; + } + + // Switch to requested channel if needed + int ret = bitbang_uart_switch_channel(channel); + + if (ret != 0) { + return ret; + } + + // Check if buffer is full + uint16_t next_head = (uart.tx_head + 1) % TX_BUFFER_SIZE; + + while (next_head == uart.tx_tail) { + // Buffer full, wait + px4_usleep(10); + } + + // Add byte to buffer + uart.tx_buffer[uart.tx_head] = byte; + uart.tx_head = next_head; + + // If not currently transmitting, start transmission + if (!uart.tx_busy.load()) { + // In single-wire mode, disable RX interrupt during TX (shared GPIO) + if (uart.single_wire) { + set_gpio_interrupt(false); + } + + // Reconfigure GPIO as output for transmission + px4_arch_configgpio(PX4_MAKE_GPIO_OUTPUT_SET(uart.gpio_pin)); + + // Get first byte from buffer + uint8_t first_byte = uart.tx_buffer[uart.tx_tail]; + uart.tx_tail = (uart.tx_tail + 1) % TX_BUFFER_SIZE; + + // Build frame: START(0) + DATA(8 bits) + STOP(1) + uart.tx_shift_reg = 0; + uart.tx_shift_reg |= (0 << 0); // Start bit + uart.tx_shift_reg |= (first_byte << 1); // Data bits + uart.tx_shift_reg |= (1 << 9); // Stop bit + + uart.tx_bit_count = 0; + uart.tx_busy.store(true); + + // Reset timer counter + STM32_TIM_SETCOUNTER(uart.timer, 0); + + // Clear any pending update interrupt + STM32_TIM_ACKINT(uart.timer, GTIM_SR_UIF); + + // Start timer + STM32_TIM_SETMODE(uart.timer, STM32_TIM_MODE_UP); + } + + return 0; +} + +int bitbang_uart_write(uint8_t channel, const uint8_t *data, size_t length) +{ + if (!uart.initialized) { + return -EINVAL; + } + + if (length == 0) { + return -EINVAL; + } + + // Switch to requested channel if needed + int ret = bitbang_uart_switch_channel(channel); + + if (ret != 0) { + return ret; + } + + for (size_t i = 0; i < length; i++) { + ret = bitbang_uart_write_byte(channel, data[i]); + + if (ret < 0) { + return ret; + } + } + + // Wait for last byte to complete + while (uart.tx_busy.load()) { + px4_usleep(10); + } + + return 0; +} + +int bitbang_uart_read(uint8_t channel, uint8_t *data, size_t length, uint32_t timeout_us) +{ + if (!uart.initialized || !data || length == 0) { + return -EINVAL; + } + + // Switch to requested channel if needed + int ret = bitbang_uart_switch_channel(channel); + + if (ret != 0) { + return ret; + } + + hrt_abstime deadline = hrt_absolute_time() + timeout_us; + size_t bytes_read = 0; + + while (bytes_read < length) { + // Check for timeout + if (timeout_us > 0 && hrt_absolute_time() >= deadline) { + break; // Return partial read on timeout + } + + // Check if data available + if (uart.rx_tail != uart.rx_head) { + // Read byte from buffer + data[bytes_read++] = uart.rx_buffer[uart.rx_tail]; + uart.rx_tail = (uart.rx_tail + 1) % RX_BUFFER_SIZE; + + } else { + // No data available, yield briefly + px4_usleep(10); + } + } + + return bytes_read; +} diff --git a/platforms/nuttx/src/px4/stm/stm32f7/CMakeLists.txt b/platforms/nuttx/src/px4/stm/stm32f7/CMakeLists.txt index b55e895db71..c9d5bff8db7 100644 --- a/platforms/nuttx/src/px4/stm/stm32f7/CMakeLists.txt +++ b/platforms/nuttx/src/px4/stm/stm32f7/CMakeLists.txt @@ -44,5 +44,9 @@ add_subdirectory(../stm32_common/spi spi) add_subdirectory(../stm32_common/tone_alarm tone_alarm) add_subdirectory(../stm32_common/version version) +if(CONFIG_SERIALPASSTHROUGH_BITBANG) + add_subdirectory(../stm32_common/bitbang_uart bitbang_uart) +endif() + add_subdirectory(px4io_serial) add_subdirectory(watchdog) diff --git a/platforms/nuttx/src/px4/stm/stm32h7/CMakeLists.txt b/platforms/nuttx/src/px4/stm/stm32h7/CMakeLists.txt index ed3e9ba0049..36faef08771 100644 --- a/platforms/nuttx/src/px4/stm/stm32h7/CMakeLists.txt +++ b/platforms/nuttx/src/px4/stm/stm32h7/CMakeLists.txt @@ -45,4 +45,8 @@ add_subdirectory(../stm32_common/spi spi) add_subdirectory(../stm32_common/tone_alarm tone_alarm) add_subdirectory(../stm32_common/version version) +if(CONFIG_SERIALPASSTHROUGH_BITBANG) + add_subdirectory(../stm32_common/bitbang_uart bitbang_uart) +endif() + add_subdirectory(px4io_serial) diff --git a/src/drivers/drv_bitbang_uart.h b/src/drivers/drv_bitbang_uart.h new file mode 100644 index 00000000000..e60ac16f973 --- /dev/null +++ b/src/drivers/drv_bitbang_uart.h @@ -0,0 +1,95 @@ +/**************************************************************************** + * + * Copyright (c) 2026 PX4 Development Team. All rights reserved. + * + * 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. + * 3. Neither the name PX4 nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * 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. + * + ****************************************************************************/ + +/** + * @file drv_bitbang_uart.h + * + * Architecture-agnostic interface for bit-bang UART. + * + * Currently implemented for STM32F7/H7 in: + * platforms/nuttx/src/px4/stm/stm32_common/bitbang_uart/ + * + * NOTE: Currently only single-wire (half-duplex) operation is implemented. + * The single_wire flag is provided in the API to make this explicit and to + * allow future extension to dual-wire (full-duplex) operation. + */ + +#pragma once + +#include +#include +#include + +#include + +__BEGIN_DECLS + +/** + * Initialize bit-bang UART + * + * @param baudrate Baudrate (typically 19200) + * @param single_wire True for single-wire half-duplex (TX and RX share one GPIO). + * False for dual-wire full-duplex (separate TX/RX GPIOs) — not yet implemented. + * @return 0 on success, negative error code on failure + */ +int bitbang_uart_init(uint32_t baudrate, bool single_wire); + +/** + * Deinitialize bit-bang UART + * + * @return 0 on success, negative error code on failure + */ +int bitbang_uart_deinit(void); + +/** + * Transmit multiple bytes + * + * @param channel Timer/GPIO channel + * @param data Pointer to data buffer + * @param length Number of bytes to transmit + * @return Number of bytes transmitted, or negative error code on failure + */ +int bitbang_uart_write(uint8_t channel, const uint8_t *data, size_t length); + +/** + * Read received bytes (blocking with timeout) + * + * @param channel Timer/GPIO channel + * @param data Pointer to buffer for received data + * @param length Number of bytes to read + * @param timeout_us Timeout in microseconds (0 = block until length bytes received) + * @return Number of bytes actually read + */ +int bitbang_uart_read(uint8_t channel, uint8_t *data, size_t length, uint32_t timeout_us); + +__END_DECLS diff --git a/src/drivers/serialpassthrough/CMakeLists.txt b/src/drivers/serialpassthrough/CMakeLists.txt new file mode 100644 index 00000000000..c5ae994d892 --- /dev/null +++ b/src/drivers/serialpassthrough/CMakeLists.txt @@ -0,0 +1,47 @@ +############################################################################ +# +# Copyright (c) 2025 PX4 Development Team. All rights reserved. +# +# 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. +# 3. Neither the name PX4 nor the names of its contributors may be +# used to endorse or promote products derived from this software +# without specific prior written permission. +# +# 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. +# +############################################################################ + +px4_add_module( + MODULE drivers__serialpassthrough + MAIN serialpassthrough + SRCS + serialpassthrough.cpp + DEPENDS + px4_platform + MODULE_CONFIG + module.yaml + ) + +if(CONFIG_SERIALPASSTHROUGH_BITBANG) + target_link_libraries(drivers__serialpassthrough PRIVATE arch_bitbang_uart) +endif() diff --git a/src/drivers/serialpassthrough/Kconfig b/src/drivers/serialpassthrough/Kconfig new file mode 100644 index 00000000000..9b0f99e8e32 --- /dev/null +++ b/src/drivers/serialpassthrough/Kconfig @@ -0,0 +1,30 @@ +menuconfig DRIVERS_SERIALPASSTHROUGH + bool "serialpassthrough" + default n + ---help--- + Enable the serialpassthrough module. + Forwards data between a UART and a MAVLink via + SERIAL_CONTROL messages. + +if DRIVERS_SERIALPASSTHROUGH + +config SERIALPASSTHROUGH_BITBANG + bool "Enable bit-bang UART support (ESC channel mode)" + default n + depends on PLATFORM_NUTTX + ---help--- + Enable bit-bang UART. + +if SERIALPASSTHROUGH_BITBANG + +config UART_BITBANG_TIMER + int "Timer instance for bit-bang UART" + default 13 + range 1 17 + ---help--- + Timer instance to use for bit-bang UART timing mode. + Default TIM13. + +endif # SERIALPASSTHROUGH_BITBANG + +endif # DRIVERS_SERIALPASSTHROUGH diff --git a/src/drivers/serialpassthrough/module.yaml b/src/drivers/serialpassthrough/module.yaml new file mode 100644 index 00000000000..dc42709c9bc --- /dev/null +++ b/src/drivers/serialpassthrough/module.yaml @@ -0,0 +1,15 @@ +module_name: Serial Passthrough (MAVLink) + +parameters: + - group: Serial Passthrough + definitions: + PASSTHRU_EN: + description: + short: Serial passthrough enable + long: | + When enabled, the serial passthrough mode is active and the + normal motor output drivers (dshot, pwm_out) are not started + at boot. + type: boolean + default: 0 + reboot_required: true diff --git a/src/drivers/serialpassthrough/serialpassthrough.cpp b/src/drivers/serialpassthrough/serialpassthrough.cpp new file mode 100644 index 00000000000..eb0c4d7a314 --- /dev/null +++ b/src/drivers/serialpassthrough/serialpassthrough.cpp @@ -0,0 +1,729 @@ +/**************************************************************************** + * + * Copyright (c) 2026 PX4 Development Team. All rights reserved. + * + * 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. + * 3. Neither the name PX4 nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * 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. + * + ****************************************************************************/ + +/** + * @file serialpassthrough.cpp + * + * Serial passthrough driven by MAVLink SERIAL_CONTROL messages. + * + * Data flow: + * SERIAL_CONTROL -> MavlinkReceiver::handle_message_serial_control() + * -> SerialPassthrough::pushFromMavlink() + * -> [mutex-protected rx buffer] + * -> SerialPassthrough::run() drains to UART + * + * UART -> SerialPassthrough::run() reads to [mutex-protected tx buffer] + * -> Mavlink::handleSerialPassthroughOutput() drains + * -> SERIAL_CONTROL (FLAG_REPLY) + */ + +#include + +#include "serialpassthrough.hpp" + +#include +#include +#include +#include +#include + +#include +#include +#include + +using device::SerialConfig::ByteSize; +using device::SerialConfig::Parity; +using device::SerialConfig::StopBits; +using device::SerialConfig::FlowControl; + +static constexpr int TASK_STACK_SIZE = PX4_STACK_ADJUSTED(1224 * 2); + +// --------------------------------------------------------------------------- +// Static member definitions +// --------------------------------------------------------------------------- + +SerialPassthrough *SerialPassthrough::_instances[SP_MAX_INSTANCES] {}; +pthread_mutex_t SerialPassthrough::_instances_mutex = PTHREAD_MUTEX_INITIALIZER; + +SerialPassthrough::SerialPassthrough(const char *device_path, unsigned baudrate, + bool swap_rxtx, bool single_wire, int esc_channel) : + _serial_port(device_path, baudrate, + ByteSize::EightBits, + Parity::None, + StopBits::One, + FlowControl::Disabled), + _baudrate(baudrate), + _swap_rxtx(swap_rxtx), + _single_wire(single_wire), + _esc_channel(esc_channel) +{ + strncpy(_dev_path, device_path, sizeof(_dev_path) - 1); + _dev_path[sizeof(_dev_path) - 1] = '\0'; + + pthread_mutex_init(&_rx_mutex, nullptr); + pthread_mutex_init(&_tx_mutex, nullptr); + pthread_mutex_init(&_meta_mutex, nullptr); +} + +SerialPassthrough::~SerialPassthrough() +{ + if (_serial_port.isOpen()) { + _serial_port.close(); + } + + pthread_mutex_destroy(&_rx_mutex); + pthread_mutex_destroy(&_tx_mutex); + pthread_mutex_destroy(&_meta_mutex); +} + +void SerialPassthrough::run() +{ + px4_prctl(PR_SET_NAME, "serialpassthrough", px4_getpid()); + + if (_esc_channel >= 0) { +#ifdef CONFIG_SERIALPASSTHROUGH_BITBANG + + // --- Bitbang UART mode (motor signal pin) --- + if (bitbang_uart_init(_baudrate, true /* single_wire */) < 0) { + PX4_ERR("Failed to init bitbang_uart at %u baud", _baudrate); + return; + } + + PX4_INFO("serialpassthrough running on ESC channel %d via bitbang at %u baud", + _esc_channel, _baudrate); + + while (!should_exit()) { + // MAVLink -> ESC + pthread_mutex_lock(&_rx_mutex); + + if (_rx_len > 0) { + uint8_t tmp[SP_BUF_SIZE]; + size_t to_write = _rx_len; + memcpy(tmp, _rx_buf, to_write); + _rx_len = 0; + pthread_mutex_unlock(&_rx_mutex); + + bitbang_uart_write((uint8_t)_esc_channel, tmp, to_write); + + } else { + pthread_mutex_unlock(&_rx_mutex); + } + + // ESC -> MAVLink: try to read up to 5ms + ssize_t nread = bitbang_uart_read((uint8_t)_esc_channel, + _ser_read_buf, sizeof(_ser_read_buf), + 5000 /* us */); + + if (nread > 0) { + pthread_mutex_lock(&_tx_mutex); + size_t space = SP_BUF_SIZE - _tx_len; + size_t to_copy = ((size_t)nread < space) ? (size_t)nread : space; + memcpy(_tx_buf + _tx_len, _ser_read_buf, to_copy); + _tx_len += to_copy; + pthread_mutex_unlock(&_tx_mutex); + } + } + + bitbang_uart_deinit(); +#else + PX4_ERR("Bitbang UART not supported on this platform"); +#endif // CONFIG_SERIALPASSTHROUGH_BITBANG + return; + } + + if (!_serial_port.isOpen()) { + if (!_serial_port.open()) { + PX4_ERR("Failed to open serial port %s", _dev_path); + return; + } + } + + if (_swap_rxtx) { + _serial_port.setSwapRxTxMode(); + } + + if (_single_wire) { + _serial_port.setSingleWireMode(); + } + + PX4_INFO("serialpassthrough running on %s at %u baud", _dev_path, _baudrate); + + while (!should_exit()) { + + // --- MAVLink -> UART --- + pthread_mutex_lock(&_rx_mutex); + + if (_rx_len > 0) { + uint8_t tmp[SP_BUF_SIZE]; + size_t to_write = _rx_len; + memcpy(tmp, _rx_buf, to_write); + _rx_len = 0; + pthread_mutex_unlock(&_rx_mutex); + + _serial_port.write(tmp, to_write); + + } else { + pthread_mutex_unlock(&_rx_mutex); + } + + // --- UART -> MAVLink --- + // Wait up to 5ms for the first byte, then drain the rest with 1ms inter-byte timeout. + // Keep timeout short so data reaches _tx_buf quickly for the MAVLink loop to send. + ssize_t nread = _serial_port.readAtLeast(_ser_read_buf, sizeof(_ser_read_buf), 1, 5); + + if (nread > 0) { + // Keep draining as long as more bytes arrive within 1ms + while (nread < (ssize_t)sizeof(_ser_read_buf)) { + ssize_t n = _serial_port.readAtLeast(_ser_read_buf + nread, + sizeof(_ser_read_buf) - nread, 1, 1); + + if (n <= 0) { break; } + + nread += n; + } + + pthread_mutex_lock(&_tx_mutex); + size_t space = SP_BUF_SIZE - _tx_len; + size_t to_copy = ((size_t)nread < space) ? (size_t)nread : space; + + if (to_copy < (size_t)nread) { + PX4_WARN("serialpassthrough: tx buffer overflow, dropping %zd bytes", + nread - (ssize_t)to_copy); + } + + memcpy(_tx_buf + _tx_len, _ser_read_buf, to_copy); + _tx_len += to_copy; + pthread_mutex_unlock(&_tx_mutex); + } + } + + if (_serial_port.isOpen()) { + _serial_port.close(); + } +} + +int SerialPassthrough::run_trampoline(int argc, char *argv[]) +{ + // Parse -i before instantiate() to get the registry key. + // This flag is injected internally by startForDevice() and is not user-facing. + uint8_t device_id = 255; + { + int myoptind = 1; + int ch; + const char *myoptarg = nullptr; + + while ((ch = px4_getopt(argc, argv, "b:d:e:i:sx", &myoptind, &myoptarg)) != EOF) { + if (ch == 'i') { device_id = (uint8_t)strtoul(myoptarg, nullptr, 0); } + } + } + + SerialPassthrough *instance = instantiate(argc, argv); + + if (!instance) { + return -1; + } + + if (!instance->register_instance(device_id)) { + PX4_ERR("serialpassthrough: max instances (%d) already running", SP_MAX_INSTANCES); + delete instance; + return -1; + } + + instance->run(); + + instance->unregister_instance(); + delete instance; + return 0; +} + +void SerialPassthrough::pushFromMavlink(const uint8_t *data, size_t len, + uint8_t sysid, uint8_t compid, uint8_t device, + uint8_t channel) +{ + // Store reply metadata + pthread_mutex_lock(&_meta_mutex); + _target_sysid = sysid; + _target_compid = compid; + _device_id = device; + _tx_channel = channel; + pthread_mutex_unlock(&_meta_mutex); + + if (len == 0) { + return; + } + + pthread_mutex_lock(&_rx_mutex); + size_t space = SP_BUF_SIZE - _rx_len; + size_t to_copy = (len < space) ? len : space; + + if (to_copy < len) { + PX4_WARN("serialpassthrough: rx buffer overflow, dropping %zu bytes", len - to_copy); + } + + memcpy(_rx_buf + _rx_len, data, to_copy); + _rx_len += to_copy; + pthread_mutex_unlock(&_rx_mutex); +} + +size_t SerialPassthrough::popToMavlink(uint8_t *buf, size_t max_len, + uint8_t *out_sysid, uint8_t *out_compid, uint8_t *out_device, + uint8_t channel) +{ + pthread_mutex_lock(&_meta_mutex); + uint8_t tx_channel = _tx_channel; + *out_sysid = _target_sysid; + *out_compid = _target_compid; + *out_device = _device_id; + pthread_mutex_unlock(&_meta_mutex); + + // Only the channel that received the request should send the reply + if (channel != tx_channel) { + PX4_DEBUG("popToMavlink: channel %u != tx_channel %u, skipping", channel, tx_channel); + return 0; + } + + pthread_mutex_lock(&_tx_mutex); + size_t to_copy = (_tx_len < max_len) ? _tx_len : max_len; + + if (to_copy > 0) { + + memcpy(buf, _tx_buf, to_copy); + _tx_len -= to_copy; + + if (_tx_len > 0) { + memmove(_tx_buf, _tx_buf + to_copy, _tx_len); + } + } + + pthread_mutex_unlock(&_tx_mutex); + return to_copy; +} + +int SerialPassthrough::startForDevice(uint8_t device_id, uint32_t baudrate) +{ + // Map device_id to device path and options + const char *dev = nullptr; + bool single_wire = false; + int esc_channel = -1; + + switch (device_id) { +#ifdef CONFIG_BOARD_SERIAL_TEL1 + + case 0: dev = CONFIG_BOARD_SERIAL_TEL1; break; +#endif +#ifdef CONFIG_BOARD_SERIAL_TEL2 + + case 1: dev = CONFIG_BOARD_SERIAL_TEL2; break; +#endif +#ifdef CONFIG_BOARD_SERIAL_GPS1 + + case 2: dev = CONFIG_BOARD_SERIAL_GPS1; break; +#endif +#ifdef CONFIG_BOARD_SERIAL_GPS2 + + case 3: dev = CONFIG_BOARD_SERIAL_GPS2; break; +#endif +#ifdef CONFIG_BOARD_SERIAL_TEL3 + + case 4: dev = CONFIG_BOARD_SERIAL_TEL3; break; +#endif +#ifdef CONFIG_BOARD_SERIAL_TEL4 + + case 5: dev = CONFIG_BOARD_SERIAL_TEL4; break; +#endif +#ifdef CONFIG_SERIALPASSTHROUGH_BITBANG + + case 20: esc_channel = 0; break; + + case 21: esc_channel = 1; break; + + case 22: esc_channel = 2; break; + + case 23: esc_channel = 3; break; + + case 24: esc_channel = 4; break; + + case 25: esc_channel = 5; break; + + case 26: esc_channel = 6; break; + + case 27: esc_channel = 7; break; +#endif + + default: + PX4_WARN("serialpassthrough: device_id %u not supported on this board", device_id); + return -1; + } + + // Check if already running on the same device_id + SerialPassthrough *sp = get_instance_for_device(device_id); + + if (sp) { + PX4_DEBUG("serialpassthrough: already running for device_id %u", device_id); + return 0; + } + +#ifdef CONFIG_SERIALPASSTHROUGH_BITBANG + + if (esc_channel >= 0) { + // The bitbang UART uses a single shared hardware timer and a single + // global state struct — only one ESC channel can be active at a time. + // Stop any existing bitbang instance and wait for it to exit before + // spawning the new task, otherwise both tasks race on the shared HW + // and corrupt each other's RX buffers via bitbang_uart_switch_channel(). + pthread_mutex_lock(&_instances_mutex); + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + if (_instances[i] && _instances[i]->_esc_channel >= 0) { + _instances[i]->request_stop(); + } + } + + pthread_mutex_unlock(&_instances_mutex); + + // Wait up to 100 ms (20 × 5 ms) for the old task to exit and + // unregister itself. The bitbang run-loop polls every 5 ms, so + // it should exit almost immediately. + for (int i = 0; i < 20; i++) { + bool any_bitbang = false; + pthread_mutex_lock(&_instances_mutex); + + for (int j = 0; j < SP_MAX_INSTANCES; j++) { + if (_instances[j] && _instances[j]->_esc_channel >= 0) { + any_bitbang = true; + break; + } + } + + pthread_mutex_unlock(&_instances_mutex); + + if (!any_bitbang) { break; } + + px4_usleep(5000); // 5 ms + } + } + +#endif // CONFIG_SERIALPASSTHROUGH_BITBANG + + if (esc_channel >= 0) { + PX4_INFO("serialpassthrough: starting on ESC bitbang channel %d at %lu baud", + esc_channel, (unsigned long)baudrate); + + } else { + PX4_INFO("serialpassthrough: starting on %s at %lu baud", + dev, (unsigned long)baudrate); + } + + // Build argv for task_spawn: ["start", "-d", dev, "-b", baud_str] or ["start", "-e", "0", "-b", baud_str] + char baud_str[12]; + snprintf(baud_str, sizeof(baud_str), "%lu", (unsigned long)baudrate); + + char esc_str[4]; + snprintf(esc_str, sizeof(esc_str), "%d", esc_channel); + + char device_id_str[4]; + snprintf(device_id_str, sizeof(device_id_str), "%u", (unsigned)device_id); + + const char *argv_buf[12]; + int argc = 0; + + argv_buf[argc++] = "start"; + argv_buf[argc++] = "-i"; + argv_buf[argc++] = device_id_str; + + if (esc_channel >= 0) { + argv_buf[argc++] = "-e"; + argv_buf[argc++] = esc_str; + + } else { + argv_buf[argc++] = "-d"; + argv_buf[argc++] = dev; + + if (single_wire) { argv_buf[argc++] = "-s"; } + } + + argv_buf[argc++] = "-b"; + argv_buf[argc++] = baud_str; + argv_buf[argc] = nullptr; + + return task_spawn(argc, (char **)argv_buf); +} + +// --------------------------------------------------------------------------- +// Instance registry +// --------------------------------------------------------------------------- + +bool SerialPassthrough::register_instance(uint8_t device_id) +{ + pthread_mutex_lock(&_instances_mutex); + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + if (_instances[i] == nullptr) { + _instances[i] = this; + _registered_device_id = device_id; + pthread_mutex_unlock(&_instances_mutex); + return true; + } + } + + pthread_mutex_unlock(&_instances_mutex); + return false; +} + +void SerialPassthrough::unregister_instance() +{ + pthread_mutex_lock(&_instances_mutex); + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + if (_instances[i] == this) { + _instances[i] = nullptr; + break; + } + } + + pthread_mutex_unlock(&_instances_mutex); +} + +SerialPassthrough *SerialPassthrough::get_instance_by_index(int index) +{ + if (index < 0 || index >= SP_MAX_INSTANCES) { return nullptr; } + + pthread_mutex_lock(&_instances_mutex); + SerialPassthrough *inst = _instances[index]; + pthread_mutex_unlock(&_instances_mutex); + return inst; +} + +SerialPassthrough *SerialPassthrough::get_instance_for_device(uint8_t device_id) +{ + pthread_mutex_lock(&_instances_mutex); + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + if (_instances[i] && _instances[i]->_registered_device_id == device_id) { + SerialPassthrough *inst = _instances[i]; + pthread_mutex_unlock(&_instances_mutex); + return inst; + } + } + + pthread_mutex_unlock(&_instances_mutex); + return nullptr; +} + +void SerialPassthrough::stop_for_device(uint8_t device_id) +{ + pthread_mutex_lock(&_instances_mutex); + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + if (_instances[i] && _instances[i]->_registered_device_id == device_id) { + _instances[i]->request_stop(); + pthread_mutex_unlock(&_instances_mutex); + return; + } + } + + pthread_mutex_unlock(&_instances_mutex); +} + +void SerialPassthrough::stop_all() +{ + pthread_mutex_lock(&_instances_mutex); + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + if (_instances[i]) { + _instances[i]->request_stop(); + } + } + + pthread_mutex_unlock(&_instances_mutex); +} + +int SerialPassthrough::task_spawn(int argc, char *argv[]) +{ + int task_id = px4_task_spawn_cmd("serialpassthrough", + SCHED_DEFAULT, + SCHED_PRIORITY_DEFAULT, + TASK_STACK_SIZE, + run_trampoline, + (char *const *)argv); + + if (task_id < 0) { + return -errno; + } + + return 0; +} + +SerialPassthrough *SerialPassthrough::instantiate(int argc, char *argv[]) +{ + const char *device = nullptr; + unsigned baudrate = 115200; + bool swap_rxtx = false; + bool single_wire = false; + int esc_channel = -1; + int myoptind = 1; + int ch; + const char *myoptarg = nullptr; + + while ((ch = px4_getopt(argc, argv, "b:d:e:i:sx", &myoptind, &myoptarg)) != EOF) { + switch (ch) { + case 'b': + baudrate = strtoul(myoptarg, nullptr, 0); + break; + + case 'd': + device = myoptarg; + break; + + case 'e': + esc_channel = (int)strtol(myoptarg, nullptr, 0); + break; + + case 's': + single_wire = true; + break; + + case 'x': + swap_rxtx = true; + break; + + case 'i': + // internal registry key injected by startForDevice(), ignore here + break; + + default: + print_usage("unrecognized flag"); + return nullptr; + } + } + + if (esc_channel >= 0) { + // Bitbang mode: no device path needed + return new SerialPassthrough("", baudrate, false, false, esc_channel); + } + + if (!device || access(device, R_OK | W_OK) != 0) { + PX4_ERR("Invalid device (-d): %s", device ? device : "(not set)"); + return nullptr; + } + + return new SerialPassthrough(device, baudrate, swap_rxtx, single_wire); +} + +int SerialPassthrough::print_status_all() +{ + pthread_mutex_lock(&_instances_mutex); + int count = 0; + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + if (_instances[i]) { + SerialPassthrough *inst = _instances[i]; + + pthread_mutex_lock(&inst->_rx_mutex); + size_t rx = inst->_rx_len; + pthread_mutex_unlock(&inst->_rx_mutex); + + pthread_mutex_lock(&inst->_tx_mutex); + size_t tx = inst->_tx_len; + pthread_mutex_unlock(&inst->_tx_mutex); + + PX4_INFO("[%d] device_id=%u dev=%s baud=%u esc_ch=%d swap=%d single=%d", + i, inst->_registered_device_id, inst->_dev_path, inst->_baudrate, + inst->_esc_channel, (int)inst->_swap_rxtx, (int)inst->_single_wire); + PX4_INFO(" pending rx(mavlink->uart)=%zu tx(uart->mavlink)=%zu", rx, tx); + count++; + } + } + + pthread_mutex_unlock(&_instances_mutex); + + if (count == 0) { + PX4_INFO("serialpassthrough: no instances running"); + } + + return 0; +} + +int SerialPassthrough::print_usage(const char *reason) +{ + if (reason) { + PX4_WARN("%s\n", reason); + } + + PRINT_MODULE_DESCRIPTION( + R"DESCR_STR( +### Description + +Serial passthrough driver driven by MAVLink SERIAL_CONTROL messages. +Bridges a MAVLink stream to a hardware UART or an ESC signal pin (bitbang). + +Only a single sender is supported at a time. Simultaneous SERIAL_CONTROL +messages from multiple senders produce undefined behaviour. + +Up to 8 instances can run simultaneously, one per device. +)DESCR_STR"); + + PRINT_MODULE_USAGE_NAME("serialpassthrough", "driver"); + PRINT_MODULE_USAGE_COMMAND("start"); + PRINT_MODULE_USAGE_PARAM_STRING('d', nullptr, "", "Serial device path", true); + PRINT_MODULE_USAGE_PARAM_INT('b', 115200, 0, 4000000, "Baudrate", true); + PRINT_MODULE_USAGE_PARAM_FLAG('x', "Swap RX/TX pins", true); + PRINT_MODULE_USAGE_PARAM_FLAG('s', "Single-wire (half-duplex) mode", true); + PRINT_MODULE_USAGE_PARAM_INT('e', -1, 0, 7, "ESC bitbang channel (0-7), instead of -d", true); + PRINT_MODULE_USAGE_PARAM_INT('i', -1, 0, 255, "Internal: instance registry key (injected by startForDevice())", true); + PRINT_MODULE_USAGE_COMMAND("stop"); + PRINT_MODULE_USAGE_COMMAND("status"); + return 0; +} + +extern "C" __EXPORT int serialpassthrough_main(int argc, char *argv[]) +{ + if (argc < 2) { + return SerialPassthrough::print_usage(nullptr); + } + + if (strcmp(argv[1], "start") == 0) { + return SerialPassthrough::task_spawn(argc - 1, argv + 1); + } + + if (strcmp(argv[1], "stop") == 0) { + SerialPassthrough::stop_all(); + return 0; + } + + if (strcmp(argv[1], "status") == 0) { + return SerialPassthrough::print_status_all(); + } + + return SerialPassthrough::print_usage("unknown command"); +} diff --git a/src/drivers/serialpassthrough/serialpassthrough.hpp b/src/drivers/serialpassthrough/serialpassthrough.hpp new file mode 100644 index 00000000000..15af295cc4c --- /dev/null +++ b/src/drivers/serialpassthrough/serialpassthrough.hpp @@ -0,0 +1,164 @@ +/**************************************************************************** + * + * Copyright (c) 2026 PX4 Development Team. All rights reserved. + * + * 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. + * 3. Neither the name PX4 nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * 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. + * + ****************************************************************************/ + +/** + * @file serialpassthrough.hpp + * + * Serial passthrough driven by MAVLink SERIAL_CONTROL messages. + * + * Exposes a thread-safe push/pop interface so MavlinkReceiver can push + * incoming payload bytes to the UART, and the Mavlink main loop can drain + * UART-received bytes back as SERIAL_CONTROL replies. + */ + +#pragma once + +#include +#include +#include +#ifdef CONFIG_SERIALPASSTHROUGH_BITBANG +#include +#endif +#include +#include +#include + +static constexpr size_t SP_BUF_SIZE = 1024; +static constexpr int SP_MAX_INSTANCES = 8; + +class SerialPassthrough +{ +public: + SerialPassthrough(const char *device_path, unsigned baudrate, bool swap_rxtx, bool single_wire, int esc_channel = -1); + ~SerialPassthrough(); + + static int task_spawn(int argc, char *argv[]); + static int run_trampoline(int argc, char *argv[]); + static SerialPassthrough *instantiate(int argc, char *argv[]); + static int print_usage(const char *reason = nullptr); + + void run(); + + /** + * Print status of all running instances. + */ + static int print_status_all(); + + /** + * Get instance by slot index (0..SP_MAX_INSTANCES-1). Returns nullptr if slot empty. + * Used by Mavlink main loop to iterate all instances. + */ + static SerialPassthrough *get_instance_by_index(int index); + + /** + * Get the running instance for a specific device_id. Returns nullptr if not running. + */ + static SerialPassthrough *get_instance_for_device(uint8_t device_id); + + /** + * Start an instance for a given device ID (from SERIAL_CONTROL device field). + * Maps device IDs to board-specific UART paths using CONFIG_BOARD_SERIAL_*. + * If already running on the same device, does nothing. + * Device IDs: 0=TEL1, 1=TEL2, 2=GPS1, 3=GPS2, 4=TEL3, 5=TEL4, 20-27=ESC bitbang ch0-7 + * Returns 0 on success, -1 if device ID is not supported on this board. + */ + static int startForDevice(uint8_t device_id, uint32_t baudrate); + + /** + * Stop the instance for a specific device_id. + */ + static void stop_for_device(uint8_t device_id); + + /** + * Stop all running instances. + */ + static void stop_all(); + + /** + * Push data received via MAVLink SERIAL_CONTROL to the UART. + * Thread-safe; called from MavlinkReceiver thread. + * channel: the MAVLink channel index (0-based) this arrived on. + */ + void pushFromMavlink(const uint8_t *data, size_t len, + uint8_t sysid, uint8_t compid, uint8_t device, + uint8_t channel); + + /** + * Pop up to max_len bytes of UART-received data for sending back as + * SERIAL_CONTROL reply. Thread-safe; called from Mavlink main loop. + * Only returns data if channel matches the channel that sent the request. + */ + size_t popToMavlink(uint8_t *buf, size_t max_len, + uint8_t *out_sysid, uint8_t *out_compid, uint8_t *out_device, + uint8_t channel); + + bool should_exit() const { return _should_exit.load(); } + void request_stop() { _should_exit.store(true); } + +private: + // --- Static instance registry --- + static SerialPassthrough *_instances[SP_MAX_INSTANCES]; + static pthread_mutex_t _instances_mutex; + + bool register_instance(uint8_t device_id); + void unregister_instance(); + + device::Serial _serial_port; + char _dev_path[20] {}; + unsigned _baudrate{115200}; + bool _swap_rxtx{false}; + bool _single_wire{false}; + int _esc_channel{-1}; // if >= 0, use bitbang_uart on this motor channel instead of _serial_port + uint8_t _registered_device_id{255}; + + px4::atomic_bool _should_exit{false}; + + // MAVLink → UART buffer (written by pushFromMavlink, drained by run()) + uint8_t _rx_buf[SP_BUF_SIZE] {}; + size_t _rx_len{0}; + pthread_mutex_t _rx_mutex; + + // UART → MAVLink buffer (written by run(), drained by popToMavlink) + uint8_t _tx_buf[SP_BUF_SIZE] {}; + size_t _tx_len{0}; + pthread_mutex_t _tx_mutex; + + // Reply metadata (sysid/compid/device/channel of last received message) + uint8_t _target_sysid{0}; + uint8_t _target_compid{0}; + uint8_t _device_id{0}; + uint8_t _tx_channel{255}; // MAVLink channel index to reply on (255 = not set) + pthread_mutex_t _meta_mutex; + + uint8_t _ser_read_buf[256] {}; +}; diff --git a/src/modules/mavlink/CMakeLists.txt b/src/modules/mavlink/CMakeLists.txt index 5c31cf89376..91ec2751127 100644 --- a/src/modules/mavlink/CMakeLists.txt +++ b/src/modules/mavlink/CMakeLists.txt @@ -147,6 +147,10 @@ px4_add_module( UNITY_BUILD ) +if(CONFIG_DRIVERS_SERIALPASSTHROUGH) + target_link_libraries(modules__mavlink PRIVATE drivers__serialpassthrough) +endif() + px4_add_unit_gtest(SRC MavlinkStatustextHandlerTest.cpp INCLUDES ${MAVLINK_LIBRARY_DIR} diff --git a/src/modules/mavlink/mavlink_main.cpp b/src/modules/mavlink/mavlink_main.cpp index f638099c77c..268f19e1938 100644 --- a/src/modules/mavlink/mavlink_main.cpp +++ b/src/modules/mavlink/mavlink_main.cpp @@ -61,6 +61,10 @@ #include "mavlink_receiver.h" #include "mavlink_main.h" +#ifdef CONFIG_DRIVERS_SERIALPASSTHROUGH +#include +#endif + #ifdef MAVLINK_UDP #include #endif @@ -2519,6 +2523,7 @@ Mavlink::task_main(int argc, char *argv[]) handleCommands(); handleAndGetCurrentCommandAck(); handleMavlinkShellOutput(); + handleSerialPassthroughOutput(); check_requested_subscriptions(); @@ -2694,6 +2699,39 @@ void Mavlink::handleStatus() } } +void Mavlink::handleSerialPassthroughOutput() +{ +#ifdef CONFIG_DRIVERS_SERIALPASSTHROUGH + // Drain all pending UART->MAVLink data from every active instance, + // one SERIAL_CONTROL message at a time. + mavlink_serial_control_t msg{}; + msg.baudrate = 0; + msg.timeout = 0; + msg.flags = SERIAL_CONTROL_FLAG_REPLY; + + uint8_t sysid, compid, device; + + for (int i = 0; i < SP_MAX_INSTANCES; i++) { + SerialPassthrough *sp = SerialPassthrough::get_instance_by_index(i); + + if (!sp) { continue; } + + while (get_free_tx_buf() >= MAVLINK_MSG_ID_SERIAL_CONTROL_LEN + MAVLINK_NUM_NON_PAYLOAD_BYTES) { + size_t n = sp->popToMavlink(msg.data, sizeof(msg.data), &sysid, &compid, &device, + (uint8_t)get_channel()); + + if (n == 0) { break; } + + PX4_DEBUG("handleSerialPassthroughOutput: sending %zu bytes", n); + msg.count = n; + msg.device = device; + mavlink_msg_serial_control_send_struct(get_channel(), &msg); + } + } + +#endif +} + void Mavlink::handleMavlinkShellOutput() { if (_mavlink_shell) { // First do a fast check before taking the lock diff --git a/src/modules/mavlink/mavlink_main.h b/src/modules/mavlink/mavlink_main.h index 82aaa715a94..b026bfb1ff1 100644 --- a/src/modules/mavlink/mavlink_main.h +++ b/src/modules/mavlink/mavlink_main.h @@ -694,6 +694,8 @@ private: void handleMavlinkShellOutput(); + void handleSerialPassthroughOutput(); + /** * Reconfigure a SiK radio if requested by MAV_SIK_RADIO_ID * diff --git a/src/modules/mavlink/mavlink_receiver.cpp b/src/modules/mavlink/mavlink_receiver.cpp index c533772eaa8..c94360ccb32 100644 --- a/src/modules/mavlink/mavlink_receiver.cpp +++ b/src/modules/mavlink/mavlink_receiver.cpp @@ -1,6 +1,6 @@ /**************************************************************************** * - * Copyright (c) 2012-2021 PX4 Development Team. All rights reserved. + * Copyright (c) 2012-2026 PX4 Development Team. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -61,6 +61,10 @@ #include "mavlink_main.h" #include "mavlink_receiver.h" +#ifdef CONFIG_DRIVERS_SERIALPASSTHROUGH +#include +#endif + #include // For DeviceId union #include @@ -1996,13 +2000,36 @@ MavlinkReceiver::handle_message_serial_control(mavlink_message_t *msg) if ((serial_control_mavlink.target_system != 0 && mavlink_system.sysid != serial_control_mavlink.target_system) || (serial_control_mavlink.target_component != 0 && - mavlink_system.compid != serial_control_mavlink.target_component)) { + mavlink_system.compid != serial_control_mavlink.target_component) || + (serial_control_mavlink.flags & SERIAL_CONTROL_FLAG_REPLY)) { return; } + // (0=TEL1, 1=TEL2, 2=GPS1, 3=GPS2, 4=TEL3, 5=TEL4) + // (20-27: ESC0 - ESC7) +#ifdef CONFIG_DRIVERS_SERIALPASSTHROUGH + + if (serial_control_mavlink.device <= 5 || + (serial_control_mavlink.device >= 20 && serial_control_mavlink.device <= 27)) { + + SerialPassthrough::startForDevice(serial_control_mavlink.device, serial_control_mavlink.baudrate); + SerialPassthrough *sp = SerialPassthrough::get_instance_for_device(serial_control_mavlink.device); + + if (sp && serial_control_mavlink.count > 0) { + sp->pushFromMavlink(serial_control_mavlink.data, + serial_control_mavlink.count, + msg->sysid, msg->compid, + serial_control_mavlink.device, + (uint8_t)_mavlink.get_channel()); + } + + return; + } + +#endif // CONFIG_DRIVERS_SERIALPASSTHROUGH + // we only support shell commands - if (serial_control_mavlink.device != SERIAL_CONTROL_DEV_SHELL - || (serial_control_mavlink.flags & SERIAL_CONTROL_FLAG_REPLY)) { + if (serial_control_mavlink.device != SERIAL_CONTROL_DEV_SHELL) { return; }