MuditaOS/module-bsp/board/linux/usb_cdc/usb_cdc.cpp

#include "bsp/usb_cdc/usb_cdc.hpp"
#include <termios.h>

namespace bsp
{
    int fd;
    xQueueHandle USBReceiveQueue;

    void usbCDCReceive(void *)
    {
        LOG_INFO("[ServiceDesktop:BSP_Driver] Start reading on fd:%d", fd);
        uint8_t inputData[SERIAL_BUFFER_LEN];
        static std::string receiveMsg;

        while (1) {
            if (uxQueueSpacesAvailable(USBReceiveQueue) != 0) {
                ssize_t length = read(fd, &inputData[0], SERIAL_BUFFER_LEN);
                if (length > 0) {
                    receiveMsg = std::string(inputData, inputData + length);
                    LOG_DEBUG("[ServiceDesktop:BSP_Driver] Received: %d signs", length);
                    xQueueSend(USBReceiveQueue, &receiveMsg, portMAX_DELAY);
                }
                else {
                    // yielding task because nothing in a buffer
                    vTaskDelay(10);
                }
            }
            else {
                LOG_DEBUG("[ServiceDesktop:BSP_Driver] USB receive Queue is full, yielding task");
                vTaskDelay(1000);
            }
        }
    }

    int usbCDCSend(std::string *sendMsg)
    {
        ssize_t t = write(fd, (*sendMsg).c_str(), (*sendMsg).length());
        delete sendMsg;

        if (t >= 0) {
            LOG_DEBUG("[ServiceDesktop:BSP_Driver] Send: %d signs", t);
            return 0;
        }
        else {
            LOG_ERROR("[ServiceDesktop:BSP_Driver] Writing to PTY failed with code: %d", errno);
            return -1;
        }
    }

    int usbCDCInit(xQueueHandle receiveQueue)
    {

        fd = 0;
        fd = open("/dev/ptmx", O_RDWR | O_NOCTTY);

        if (fd == -1) {
            return (-1);
        }

        grantpt(fd);
        unlockpt(fd);

        char *pts_name = ptsname(fd);
        LOG_INFO("[ServiceDesktop:BSP_Driver] VCOMAPPInit linux ptsname: %s", pts_name);
        struct termios newtio;
        memset(&newtio, 0, sizeof(newtio));
        struct termios oldtio;
        tcgetattr(fd, &oldtio);

        newtio             = oldtio;
        newtio.c_cflag     = SERIAL_BAUDRATE | CS8 | CLOCAL | CREAD;
        newtio.c_iflag     = 0;
        newtio.c_oflag     = 0;
        newtio.c_lflag     = 0;
        newtio.c_cc[VMIN]  = 1;
        newtio.c_cc[VTIME] = 0;
        tcflush(fd, TCIFLUSH);

        cfsetispeed(&newtio, SERIAL_BAUDRATE);
        cfsetospeed(&newtio, SERIAL_BAUDRATE);
        tcsetattr(fd, TCSANOW, &newtio);

        xTaskHandle taskHandleReceive;
        USBReceiveQueue = receiveQueue;

        BaseType_t task_error = xTaskCreate(
            usbCDCReceive, "USBLinuxReceive", SERIAL_BUFFER_LEN * 8, (void *)1, tskIDLE_PRIORITY, &taskHandleReceive);

        if (task_error != pdPASS) {
            LOG_ERROR("[ServiceDesktop:BSP_Driver] Failed to start freertos USB_Linux_Receive");
        }

        return (fd);
    }
} // namespace bsp