src/uart_ll: lowlevel serial driver
This commit is contained in:
Gwenhael Goavec-Merou
parent
a0180f0bc6
commit
b79b5d652b
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@ -203,9 +203,12 @@ if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
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list(APPEND OPENFPGALOADER_HEADERS src/pathHelper.hpp)
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endif()
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# libusb_attach_kernel_driver is only available on Linux.
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if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
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# libusb_attach_kernel_driver is only available on Linux.
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add_definitions(-DATTACH_KERNEL)
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# uart_ll only tested on Linux
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target_sources(openFPGALoader PRIVATE src/uart_ll.cpp)
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list (APPEND OPENFPGALOADER_HEADERS src/uart_ll.hpp)
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endif()
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if (ENABLE_UDEV)
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@ -0,0 +1,341 @@
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// SPDX-License-Identifier: Apache-2.0
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/*
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* Copyright (C) 2022 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
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*/
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#include "uart_ll.hpp"
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#include <errno.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <termios.h>
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#include <unistd.h>
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#include <stdexcept>
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#include "display.hpp"
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Uart_ll::Uart_ll(const std::string &filename, uint32_t clkHz,
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uint8_t byteSize, bool twoStopBits): _clkHz(clkHz),
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_byteSize(CS8), _stopBits(twoStopBits)
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{
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switch (byteSize) {
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case 5:
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_byteSize = CS5;
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break;
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case 6:
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_byteSize = CS6;
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break;
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case 7:
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_byteSize = CS7;
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break;
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case 8:
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_byteSize = CS8;
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break;
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default:
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std::runtime_error("Error: byteSize must be between 5 and 8");
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}
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/* open device */
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_serial = open(filename.c_str(), O_RDWR | O_NOCTTY | O_NONBLOCK);
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if (_serial == -1)
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throw std::runtime_error("Error: failed to open " + filename +
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" (" + strerror(errno) + ")");
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/* configure port */
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if (port_configure() < 0)
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throw std::runtime_error("Error: port configuration failed");
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// set baudrate
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if (setClkFreq(_clkHz) < -1)
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throw std::runtime_error("Error: baudrate configuration failed");
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}
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Uart_ll::~Uart_ll() {
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int err;
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/* reapply original configuration */
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if ((err = tcsetattr(_serial, TCSANOW, &_prev_termios)) != 0) {
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printError("error %d from tcsetattr: " + std::to_string(err));
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}
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/* close device */
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close(_serial);
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}
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int Uart_ll::port_configure(void)
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{
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int err;
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/* store current configuration */
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if ((err = tcgetattr(_serial, &_prev_termios)) != 0) {
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printError("error to retrieve current configuration: " +
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std::to_string(err) + " " + strerror(errno));
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return -1;
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}
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/* copy termios structure configuration */
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memcpy(&_curr_termios, &_prev_termios, sizeof(_prev_termios));
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/* controls flags */
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/* clear default configuration */
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_curr_termios.c_cflag &= ~(CSIZE | CSTOPB | CRTSCTS);
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/* set byte size (5,6,7,8)
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* enable receiver
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* disable modem control lines
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*/
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_curr_termios.c_cflag |= (_byteSize | CREAD | CLOCAL);
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/* 2 stop bits ? */
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if (_stopBits)
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_curr_termios.c_cflag |= CSTOPB;
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/* input mode */
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_curr_termios.c_iflag &= ~IGNBRK; // disable break processing
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_curr_termios.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl
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/* output mode */
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_curr_termios.c_oflag = 0; // no remapping, no delays
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// no canonical processing
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_curr_termios.c_lflag = 0; // no signaling chars, no echo,
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_curr_termios.c_cc[VMIN] = 0; // read doesn't block
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_curr_termios.c_cc[VTIME] = 5; // 0.5 seconds read timeout
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if ((err = tcsetattr(_serial, TCSANOW, &_curr_termios)) != 0) {
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printError("error %d from tcsetattr: " + std::to_string(err) +
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" " + strerror(errno));
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return -1;
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}
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return 0;
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}
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int Uart_ll::setClkFreq(uint32_t clkHz)
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{
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int err;
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speed_t baud = freq_to_baud(clkHz);
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/* set input baudrate */
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cfsetispeed(&_curr_termios, baud);
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/* set output baudrate */
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cfsetospeed(&_curr_termios, baud);
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/* apply modifications */
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if ((err = tcsetattr(_serial, TCSANOW, &_curr_termios)) != 0) {
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printError("Error during baudrate configuration: tcsetattr == "
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+ std::to_string(err));
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return -1;
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}
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_clkHz = clkHz;
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_baudrate = baud;
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return clkHz;
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}
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uint32_t Uart_ll::getClkFreq()
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{
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return baud_to_freq(cfgetispeed(&_curr_termios));
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}
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int Uart_ll::write(const unsigned char *data, int size)
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{
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const char *ptr = reinterpret_cast<const char *>(data);
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ssize_t len = size;
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/* set a select to block for serial data or timeout */
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fd_set fd_write;
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timespec timeout_ts;
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timeout_ts.tv_sec = 5;
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timeout_ts.tv_nsec = 0;
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do {
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ssize_t s = ::write(_serial, ptr, len);
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if (s < 0) {
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if (errno != 11) {
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printError("Error: Failed to write: " + std::to_string(errno) +
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" " + strerror(errno));
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return s;
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}
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} else if (s == len) {
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break;
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}
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ptr += s;
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len -= s;
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FD_ZERO(&fd_write);
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FD_SET(_serial, &fd_write);
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int r = pselect(_serial + 1, NULL, &fd_write, NULL, &timeout_ts, NULL);
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if (r < 0) {
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int t = errno;
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printf("uart_ll errror: write failed with error %d (%d: %s)\n", r,
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errno, strerror(errno));
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// interrupt ?
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return (t == EINTR) ? -1 : -2;
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}
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/* timeout */
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if (r == 0)
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return -3;
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if (!FD_ISSET(_serial, &fd_write)) {
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printError(
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"uart_ll error: something to write but from file descriptor\n");
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return -4;
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}
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} while (len > 0);
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return size;
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}
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int Uart_ll::read(std::string *buf, int maxsize)
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{
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int size = maxsize;
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int read_size = 0;
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char c;
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do {
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ssize_t ret = ::read(_serial, &c, 1);
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if (ret < 0) {
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char mess[256];
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snprintf(mess, 256, "Error: Failed to read: %d %s",
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errno, strerror(errno));
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printError(mess);
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return ret;
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}
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buf->append(1, c);
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read_size++;
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size--;
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} while (size > 0);
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return read_size;
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}
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bool Uart_ll::flush(int maxsize)
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{
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int size = maxsize;
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int read_size = 0;
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char c;
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int timeout = 1000;
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std::string buf;
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do {
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ssize_t ret = ::read(_serial, &c, 1);
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if (ret < 0) {
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if (errno == 11)
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return true;
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char mess[256];
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snprintf(mess, 256, "Error: Failed to read: %d %s",
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errno, strerror(errno));
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printError(mess);
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return ret;
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} else if (ret == 0) {
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timeout--;
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} else {
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buf.append(1, c);
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read_size++;
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size--;
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}
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} while (size > 0 && timeout > 0);
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return true;
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}
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int Uart_ll::read_until(std::string *buf, uint8_t end)
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{
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int read_size = 0;
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char c[256];
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bool is_end = false;
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/* set a select to block for serial data or timeout */
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fd_set fd_read;
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timespec timeout_ts;
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timeout_ts.tv_sec = 5;
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timeout_ts.tv_nsec = 0;
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do {
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FD_ZERO(&fd_read);
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FD_SET(_serial, &fd_read);
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int r = pselect(_serial + 1, &fd_read, NULL, NULL, &timeout_ts, NULL);
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if (r < 0) {
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int t = errno;
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printf("uart_ll errror: read failed with error %d (%d: %s)\n", r,
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errno, strerror(errno));
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if (t == EINTR) // interrupt
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return -1;
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return -2;
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}
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/* timeout */
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if (r == 0)
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return -3;
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if (!FD_ISSET(_serial, &fd_read)) {
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printError(
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"uart_ll error: something to read but from file descriptor\n");
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return -4;
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}
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int ret = ::read(_serial, c, 256);
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if (ret < 0) {
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if (errno == 11) { // temporarily unavailable
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printError("uart_ll error: device unavailable\n");
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return -5;
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}
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}
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for (int i = 0; i < ret; i++) {
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if (c[i] == '\r' && end == '\n')
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continue;
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if (c[i] == end) {
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is_end = true;
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break;
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}
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buf->append(1, c[i]);
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read_size++;
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}
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} while (!is_end);
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return read_size;
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}
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speed_t Uart_ll::freq_to_baud(uint32_t clkHz)
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{
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if (clkHz > 115200)
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return B230400;
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else if (clkHz > 57600)
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return B115200;
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else if (clkHz > 38400)
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return B57600;
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else if (clkHz > 19200)
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return B38400;
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else if (clkHz > 9600)
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return B19200;
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else if (clkHz > 4800)
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return B9600;
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else if (clkHz > 2400)
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return B4800;
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else // no exhaustive list
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return B2400;
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}
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uint32_t Uart_ll::baud_to_freq(speed_t baud)
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{
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switch(baud) {
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case B230400:
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return 230400;
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case B115200:
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return 115200;
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case B57600:
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return 57600;
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case B38400:
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return 38400;
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case B19200:
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return 19200;
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case B9600:
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return 9600;
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case B4800:
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return 4800;
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default: // no exhaustive list
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return 2400;
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}
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}
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@ -0,0 +1,93 @@
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// SPDX-License-Identifier: Apache-2.0
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/*
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* Copyright (C) 2022 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
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*/
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#ifndef SRC_UART_LL_HPP_
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#define SRC_UART_LL_HPP_
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#include <stdint.h>
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#include <termios.h>
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#include <string>
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/*!
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* \file uart_ll
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* \class Uart_ll
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* \brief low level implementation for UART protocol
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* \author Gwenhael Goavec-Merou
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*/
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class Uart_ll {
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public:
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/*!
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* \brief constructor
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* \param[in] filename: /dev/ttyxx path
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* \param[in] clkHz: baudrate (in Hz)
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* \param[in] byteSize: transaction size (5 to 8)
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* \param[in] stopBits: 1 or 2 stop bit
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* \param[in] firmware_path: firmware to load
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*/
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Uart_ll(const std::string &filename, uint32_t clkHz,
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uint8_t byteSize, bool stopBits);
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~Uart_ll();
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int setClkFreq(uint32_t clkHz);
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uint32_t getClkFreq();
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/*!
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* \brief send buffer content
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* \param[in] data: buffer
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* \param[in] size: number of char to send
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* \return size if ok, < 0 otherwise
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*/
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int write(const unsigned char *data, int size);
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/*!
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* \brief read maxsize char from device
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* \param[in] buf: buffer to fill
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* \param[in] maxsize: number of char to read
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* \return read size if ok, < 0 otherwise
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*/
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int read(std::string *buf, int maxsize);
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/*!
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* \brief read char from device until receiving end char
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* \param[in] buf: buffer to fill
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* \param[in] end: number of char to read
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* \return read size if ok, < 0 otherwise
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*/
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int read_until(std::string *buf, uint8_t end = '\n');
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/*!
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* \brief flush by reading maxsize char from device
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* \param[in] maxsize: number of char to read
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* \return true if ok, false otherwise
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*/
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bool flush(int maxsize=64);
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private:
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/*!
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* \brief serial port configuration
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* \return -1 if something fails, 0 otherwise
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*/
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int port_configure(void);
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/*!
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* \brief convert a frequency to the baudrate (BXXX)
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* \param[in] clkHz: clock frequency
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* \return the corresponding baudrate value
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*/
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speed_t freq_to_baud(uint32_t clkHz);
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/*!
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* \brief convert the baudrate (BXXX) to the corresponding frequency
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* \param[in] baud: a speed_t (BXXX) value
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* \return the corresponding frequency (Hz)
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*/
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uint32_t baud_to_freq(speed_t baud);
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struct termios _prev_termios; /*! original serial port configuration */
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struct termios _curr_termios; /*! current serial port configuration */
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speed_t _baudrate; /*! current baudrate */
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uint32_t _clkHz; /*! current clk frequency */
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int _serial; /*! device file descriptor */
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uint32_t _byteSize; /*! transfer size */
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bool _stopBits;
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};
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#endif // SRC_UART_LL_HPP_
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