libdc/src/serial_win32.c
Jef Driesen bfeab10515 Add support for modifying the receive latency.
Currently this isn't used or needed anywhere, but the research has been
done, and it would be silly to drop the knowledge. We may need it in the
future.
2014-03-28 09:39:26 +01:00

663 lines
15 KiB
C

/*
* libdivecomputer
*
* Copyright (C) 2008 Jef Driesen
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*/
#include <stdlib.h>
#define NOGDI
#include <windows.h>
#include "serial.h"
#include "context-private.h"
struct serial_t {
/* Library context. */
dc_context_t *context;
/*
* The file descriptor corresponding to the serial port.
*/
HANDLE hFile;
/*
* Serial port settings are saved into this variables immediately
* after the port is opened. These settings are restored when the
* serial port is closed.
*/
DCB dcb;
COMMTIMEOUTS timeouts;
/* Half-duplex settings */
int halfduplex;
unsigned int baudrate;
unsigned int nbits;
};
int
serial_enumerate (serial_callback_t callback, void *userdata)
{
// Open the registry key.
HKEY hKey;
LONG rc = RegOpenKeyExA (HKEY_LOCAL_MACHINE, "HARDWARE\\DEVICEMAP\\SERIALCOMM", 0, KEY_QUERY_VALUE, &hKey);
if (rc != ERROR_SUCCESS) {
if (rc == ERROR_FILE_NOT_FOUND)
return 0;
else
return -1;
}
// Get the number of values.
DWORD count = 0;
rc = RegQueryInfoKey (hKey, NULL, NULL, NULL, NULL, NULL, NULL, &count, NULL, NULL, NULL, NULL);
if (rc != ERROR_SUCCESS) {
RegCloseKey(hKey);
return -1;
}
for (DWORD i = 0; i < count; ++i) {
// Get the value name, data and type.
char name[512], data[512];
DWORD name_len = sizeof (name);
DWORD data_len = sizeof (data);
DWORD type = 0;
rc = RegEnumValueA (hKey, i, name, &name_len, NULL, &type, (LPBYTE) data, &data_len);
if (rc != ERROR_SUCCESS) {
RegCloseKey(hKey);
return -1;
}
// Ignore non-string values.
if (type != REG_SZ)
continue;
// Prevent a possible buffer overflow.
if (data_len >= sizeof (data)) {
RegCloseKey(hKey);
return -1;
}
// Null terminate the string.
data[data_len] = 0;
callback (data, userdata);
}
RegCloseKey(hKey);
return 0;
}
//
// Open the serial port.
//
int
serial_open (serial_t **out, dc_context_t *context, const char* name)
{
if (out == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
INFO (context, "Open: name=%s", name ? name : "");
// Build the device name.
const char *devname = NULL;
char buffer[MAX_PATH] = "\\\\.\\";
if (name && strncmp (name, buffer, 4) != 0) {
size_t length = strlen (name) + 1;
if (length + 4 > sizeof (buffer))
return -1;
memcpy (buffer + 4, name, length);
devname = buffer;
} else {
devname = name;
}
// Allocate memory.
serial_t *device = (serial_t *) malloc (sizeof (serial_t));
if (device == NULL) {
SYSERROR (context, ERROR_OUTOFMEMORY);
return -1; // ERROR_OUTOFMEMORY (Not enough storage is available to complete this operation)
}
// Library context.
device->context = context;
// Default to full-duplex.
device->halfduplex = 0;
device->baudrate = 0;
device->nbits = 0;
// Open the device.
device->hFile = CreateFileA (devname,
GENERIC_READ | GENERIC_WRITE, 0,
NULL, // No security attributes.
OPEN_EXISTING,
0, // Non-overlapped I/O.
NULL);
if (device->hFile == INVALID_HANDLE_VALUE) {
SYSERROR (context, GetLastError ());
free (device);
return -1;
}
// Retrieve the current communication settings and timeouts,
// to be able to restore them when closing the device.
// It is also used to check if the obtained handle
// represents a serial device.
if (!GetCommState (device->hFile, &device->dcb) ||
!GetCommTimeouts (device->hFile, &device->timeouts)) {
SYSERROR (context, GetLastError ());
CloseHandle (device->hFile);
free (device);
return -1;
}
*out = device;
return 0;
}
//
// Close the serial port.
//
int
serial_close (serial_t *device)
{
if (device == NULL)
return 0;
// Restore the initial communication settings and timeouts.
if (!SetCommState (device->hFile, &device->dcb) ||
!SetCommTimeouts (device->hFile, &device->timeouts)) {
SYSERROR (device->context, GetLastError ());
CloseHandle (device->hFile);
free (device);
return -1;
}
// Close the device.
if (!CloseHandle (device->hFile)) {
SYSERROR (device->context, GetLastError ());
free (device);
return -1;
}
// Free memory.
free (device);
return 0;
}
//
// Configure the serial port (baudrate, databits, parity, stopbits and flowcontrol).
//
int
serial_configure (serial_t *device, int baudrate, int databits, int parity, int stopbits, int flowcontrol)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
INFO (device->context, "Configure: baudrate=%i, databits=%i, parity=%i, stopbits=%i, flowcontrol=%i",
baudrate, databits, parity, stopbits, flowcontrol);
// Retrieve the current settings.
DCB dcb;
if (!GetCommState (device->hFile, &dcb)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
dcb.fBinary = TRUE; // Enable Binary Transmission
dcb.fAbortOnError = FALSE;
// Baudrate.
dcb.BaudRate = baudrate;
// Character size.
if (databits >= 5 && databits <= 8)
dcb.ByteSize = databits;
else
return -1;
// Parity checking.
switch (parity) {
case SERIAL_PARITY_NONE: // No parity
dcb.Parity = NOPARITY;
dcb.fParity = FALSE;
break;
case SERIAL_PARITY_EVEN: // Even parity
dcb.Parity = EVENPARITY;
dcb.fParity = TRUE;
break;
case SERIAL_PARITY_ODD: // Odd parity
dcb.Parity = ODDPARITY;
dcb.fParity = TRUE;
break;
default:
return -1;
}
// Stopbits.
switch (stopbits) {
case 1: // One stopbit
dcb.StopBits = ONESTOPBIT;
break;
case 2: // Two stopbits
dcb.StopBits = TWOSTOPBITS;
break;
default:
return -1;
}
// Flow control.
switch (flowcontrol) {
case SERIAL_FLOWCONTROL_NONE: // No flow control.
dcb.fInX = FALSE;
dcb.fOutX = FALSE;
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fDtrControl = DTR_CONTROL_ENABLE;
dcb.fRtsControl = RTS_CONTROL_ENABLE;
break;
case SERIAL_FLOWCONTROL_HARDWARE: // Hardware (RTS/CTS) flow control.
dcb.fInX = FALSE;
dcb.fOutX = FALSE;
dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = TRUE;
dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;
dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;
break;
case SERIAL_FLOWCONTROL_SOFTWARE: // Software (XON/XOFF) flow control.
dcb.fInX = TRUE;
dcb.fOutX = TRUE;
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fDtrControl = DTR_CONTROL_ENABLE;
dcb.fRtsControl = RTS_CONTROL_ENABLE;
break;
default:
return -1;
}
// Apply the new settings.
if (!SetCommState (device->hFile, &dcb)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
device->baudrate = baudrate;
device->nbits = 1 + databits + stopbits + (parity ? 1 : 0);
return 0;
}
//
// Configure the serial port (timeouts).
//
int
serial_set_timeout (serial_t *device, long timeout)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
INFO (device->context, "Timeout: value=%li", timeout);
// Retrieve the current timeouts.
COMMTIMEOUTS timeouts;
if (!GetCommTimeouts (device->hFile, &timeouts)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
// Update the settings.
if (timeout < 0) {
// Blocking mode.
timeouts.ReadIntervalTimeout = 0;
timeouts.ReadTotalTimeoutMultiplier = 0;
timeouts.ReadTotalTimeoutConstant = 0;
timeouts.WriteTotalTimeoutMultiplier = 0;
timeouts.WriteTotalTimeoutConstant = 0;
} else if (timeout == 0) {
// Non-blocking mode.
timeouts.ReadIntervalTimeout = MAXDWORD;
timeouts.ReadTotalTimeoutMultiplier = 0;
timeouts.ReadTotalTimeoutConstant = 0;
timeouts.WriteTotalTimeoutMultiplier = 0;
timeouts.WriteTotalTimeoutConstant = 0;
} else {
// Standard timeout mode.
timeouts.ReadIntervalTimeout = 0;
timeouts.ReadTotalTimeoutMultiplier = 0;
timeouts.ReadTotalTimeoutConstant = timeout;
timeouts.WriteTotalTimeoutMultiplier = 0;
timeouts.WriteTotalTimeoutConstant = 0;
}
// Activate the new timeouts.
if (!SetCommTimeouts (device->hFile, &timeouts)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return 0;
}
//
// Configure the serial port (recommended size of the input/output buffers).
//
int
serial_set_queue_size (serial_t *device, unsigned int input, unsigned int output)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
if (!SetupComm (device->hFile, input, output)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return 0;
}
int
serial_set_halfduplex (serial_t *device, int value)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
device->halfduplex = value;
return 0;
}
int
serial_set_latency (serial_t *device, unsigned int milliseconds)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
return 0;
}
int
serial_read (serial_t *device, void* data, unsigned int size)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
DWORD dwRead = 0;
if (!ReadFile (device->hFile, data, size, &dwRead, NULL)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
HEXDUMP (device->context, DC_LOGLEVEL_INFO, "Read", (unsigned char *) data, dwRead);
return dwRead;
}
int
serial_write (serial_t *device, const void* data, unsigned int size)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
LARGE_INTEGER begin, end, freq;
if (device->halfduplex) {
// Get the current time.
if (!QueryPerformanceFrequency(&freq) ||
!QueryPerformanceCounter(&begin)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
}
DWORD dwWritten = 0;
if (!WriteFile (device->hFile, data, size, &dwWritten, NULL)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
if (device->halfduplex) {
// Get the current time.
if (!QueryPerformanceCounter(&end)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
// Calculate the elapsed time (microseconds).
unsigned long elapsed = 1000000.0 * (end.QuadPart - begin.QuadPart) / freq.QuadPart + 0.5;
// Calculate the expected duration (microseconds). A 2 millisecond fudge
// factor is added because it improves the success rate significantly.
unsigned long expected = 1000000.0 * device->nbits / device->baudrate * size + 0.5 + 2000;
// Wait for the remaining time.
if (elapsed < expected) {
unsigned long remaining = expected - elapsed;
// The remaining time is rounded up to the nearest millisecond
// because the Windows Sleep() function doesn't have a higher
// resolution.
serial_sleep (device, (remaining + 999) / 1000);
}
}
HEXDUMP (device->context, DC_LOGLEVEL_INFO, "Write", (unsigned char *) data, dwWritten);
return dwWritten;
}
int
serial_flush (serial_t *device, int queue)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
INFO (device->context, "Flush: queue=%u, input=%i, output=%i", queue,
serial_get_received (device),
serial_get_transmitted (device));
DWORD flags = 0;
switch (queue) {
case SERIAL_QUEUE_INPUT:
flags = PURGE_RXABORT | PURGE_RXCLEAR;
break;
case SERIAL_QUEUE_OUTPUT:
flags = PURGE_TXABORT | PURGE_TXCLEAR;
break;
default:
flags = PURGE_RXABORT | PURGE_RXCLEAR | PURGE_TXABORT | PURGE_TXCLEAR;
break;
}
if (!PurgeComm (device->hFile, flags)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return 0;
}
int
serial_send_break (serial_t *device)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
if (!SetCommBreak (device->hFile)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
Sleep (250);
if (!ClearCommBreak (device->hFile)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return 0;
}
int
serial_set_break (serial_t *device, int level)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
INFO (device->context, "Break: value=%i", level);
if (level) {
if (!SetCommBreak (device->hFile)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
} else {
if (!ClearCommBreak (device->hFile)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
}
return 0;
}
int
serial_set_dtr (serial_t *device, int level)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
INFO (device->context, "DTR: value=%i", level);
int status = (level ? SETDTR : CLRDTR);
if (!EscapeCommFunction (device->hFile, status)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return 0;
}
int
serial_set_rts (serial_t *device, int level)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
INFO (device->context, "RTS: value=%i", level);
int status = (level ? SETRTS : CLRRTS);
if (!EscapeCommFunction (device->hFile, status)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return 0;
}
int
serial_get_received (serial_t *device)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
COMSTAT stats;
if (!ClearCommError (device->hFile, NULL, &stats)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return stats.cbInQue;
}
int
serial_get_transmitted (serial_t *device)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
COMSTAT stats;
if (!ClearCommError (device->hFile, NULL, &stats)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
return stats.cbOutQue;
}
int
serial_get_line (serial_t *device, int line)
{
if (device == NULL)
return -1; // ERROR_INVALID_PARAMETER (The parameter is incorrect)
DWORD stats = 0;
if (!GetCommModemStatus (device->hFile, &stats)) {
SYSERROR (device->context, GetLastError ());
return -1;
}
switch (line) {
case SERIAL_LINE_DCD:
return (stats & MS_RLSD_ON) == MS_RLSD_ON;
case SERIAL_LINE_CTS:
return (stats & MS_CTS_ON) == MS_CTS_ON;
case SERIAL_LINE_DSR:
return (stats & MS_DSR_ON) == MS_DSR_ON;
case SERIAL_LINE_RNG:
return (stats & MS_RING_ON) == MS_RING_ON;
default:
return -1;
}
return 0;
}
int
serial_sleep (serial_t *device, unsigned long timeout)
{
if (device == NULL)
return -1;
INFO (device->context, "Sleep: value=%lu", timeout);
Sleep (timeout);
return 0;
}