btstack/platform/posix/btstack_uart_posix.c

/*
 * Copyright (C) 2016 BlueKitchen GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
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 *    notice, this list of conditions and the following disclaimer in the
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 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 * 4. Any redistribution, use, or modification is done solely for
 *    personal benefit and not for any commercial purpose or for
 *    monetary gain.
 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
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 */

/*
 *  btstack_uart_posix.c
 *
 *  Common code to access serial port via POSIX interface
 *  Used by hci_transport_h4_posix.c and hci_transport_h5.posix
 *
 */

#include "btstack_uart_posix.h"
#include "btstack_debug.h"

#include <termios.h>  /* POSIX terminal control definitions */
#include <fcntl.h>    /* File control definitions */
// #include <unistd.h>   /* UNIX standard function definitions */
// #include <stdio.h>
// #include <string.h>

int btstack_uart_posix_open(const char * device_name, int flowcontrol, uint32_t baudrate){

    struct termios toptions;
    int flags = O_RDWR | O_NOCTTY | O_NONBLOCK;
    int fd = open(device_name, flags);
    if (fd == -1)  {
        perror("init_serialport: Unable to open port ");
        perror(device_name);
        return -1;
    }
    
    if (tcgetattr(fd, &toptions) < 0) {
        perror("init_serialport: Couldn't get term attributes");
        return -1;
    }
    
    cfmakeraw(&toptions);   // make raw

    // 8N1
    toptions.c_cflag &= ~CSTOPB;
    toptions.c_cflag |= CS8;

    if (flowcontrol) {
        // with flow control
        toptions.c_cflag |= CRTSCTS;
    } else {
        // no flow control
        toptions.c_cflag &= ~CRTSCTS;
    }
    
    toptions.c_cflag |= CREAD | CLOCAL;  // turn on READ & ignore ctrl lines
    toptions.c_iflag &= ~(IXON | IXOFF | IXANY); // turn off s/w flow ctrl
    
    // see: http://unixwiz.net/techtips/termios-vmin-vtime.html
    toptions.c_cc[VMIN]  = 1;
    toptions.c_cc[VTIME] = 0;
    
    if(tcsetattr(fd, TCSANOW, &toptions) < 0) {
        perror("init_serialport: Couldn't set term attributes");
        return -1;
    }
    
    // also set baudrate
    if (btstack_uart_posix_set_baudrate(fd, baudrate) < 0){
        return -1;
    }

    return fd;
}

int btstack_uart_posix_set_baudrate(int fd, uint32_t baudrate){
    log_info("h4_set_baudrate %u", baudrate);

    struct termios toptions;

    if (tcgetattr(fd, &toptions) < 0) {
        perror("init_serialport: Couldn't get term attributes");
        return -1;
    }
    
    speed_t brate = baudrate; // let you override switch below if needed
    switch(baudrate) {
        case 57600:  brate=B57600;  break;
        case 115200: brate=B115200; break;
#ifdef B230400
        case 230400: brate=B230400; break;
#endif
#ifdef B460800
        case 460800: brate=B460800; break;
#endif
#ifdef B921600
        case 921600: brate=B921600; break;
#endif

// Hacks to switch to 2/3 mbps on FTDI FT232 chipsets
// requires special config in Info.plist or Registry
        case 2000000: 
#if defined(HAVE_POSIX_B300_MAPPED_TO_2000000)
            log_info("hci_transport_posix: using B300 for 2 mbps");
            brate=B300; 
#elif defined(HAVE_POSIX_B1200_MAPPED_TO_2000000)
           log_info("hci_transport_posix: using B1200 for 2 mbps");
            brate=B1200;
#endif
            break;
        case 3000000:
#if defined(HAVE_POSIX_B600_MAPPED_TO_3000000)
            log_info("hci_transport_posix: using B600 for 3 mbps");
            brate=B600;
#elif defined(HAVE_POSIX_B2400_MAPPED_TO_3000000)
            log_info("hci_transport_posix: using B2400 for 3 mbps");
            brate=B2400;
#endif
            break;
        default:
            break;
    }
    cfsetospeed(&toptions, brate);
    cfsetispeed(&toptions, brate);

    if( tcsetattr(fd, TCSANOW, &toptions) < 0) {
        perror("init_serialport: Couldn't set term attributes");
        return -1;
    }

    return 0;
}