cmSerialPort.h/c : Initial commit.

This commit is contained in:
kevin.larke 2020-02-21 12:34:22 -05:00
parent e0a683e8b1
commit 575db4382d
2 changed files with 652 additions and 0 deletions

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cmSerialPort.c Normal file
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#include "cmPrefix.h"
#include "cmGlobal.h"
#include "cmRpt.h"
#include "cmErr.h"
#include "cmCtx.h"
#include "cmMem.h"
#include "cmMallocDebug.h"
#include "cmSerialPort.h"
#include "cmThread.h"
#include <poll.h>
#include <termios.h>
#include <unistd.h> // close()
#include <fcntl.h> // O_RDWR
#include <sys/ioctl.h> // TIOCEXCL
typedef struct cmSerialPort_str
{
cmErr_t _err;
cmThreadH_t _thH;
const char* _deviceStr;
int _deviceH;
unsigned _baudRate;
unsigned _cfgFlags;
cmSeCallbackFunc_t _cbFunc;
void* _cbArg;
struct termios _ttyAttrs;
struct pollfd _pollfd;
unsigned _pollPeriodMs;
} cmSerialPort_t;
cmSerialPort_t* _cmSePtrFromHandle( cmSeH_t h )
{
cmSerialPort_t* p = (cmSerialPort_t*)h.h;
assert(p!=NULL);
return p;
}
void _cmSeSetClosedState( cmSerialPort_t* p )
{
if( p->_deviceStr != NULL )
cmMemFree((char*)(p->_deviceStr));
p->_deviceH = -1;
p->_deviceStr = NULL;
p->_baudRate = 0;
p->_cfgFlags = 0;
p->_cbFunc = NULL;
p->_cbArg = NULL;
}
cmSeRC_t _cmSeGetAttributes( cmSerialPort_t* p, struct termios* attr )
{
if( tcgetattr(p->_deviceH, attr) == -1 )
return cmErrSysMsg(&p->_err,kGetAttrFailSeRC,errno,"Error getting tty attributes from %s.",p->_deviceStr);
return kOkSeRC;
}
cmSeRC_t _cmSePoll( cmSerialPort_t* p, unsigned timeOutMs )
{
cmSeRC_t rc = kOkSeRC;
int sysRC;
if((sysRC = poll(&p->_pollfd,1,timeOutMs)) == 0)
rc = kTimeOutSeRC;
else
{
if( sysRC < 0 )
rc = cmErrSysMsg(&p->_err,kReadFailSeRC,errno,"Poll failed on serial port.");
}
return rc;
}
bool _cmSeThreadFunc(void* param)
{
cmSerialPort_t* p = (cmSerialPort_t*)param;
cmSeH_t h;
h.h = p;
unsigned readN;
if( cmSeIsOpen(h) )
cmSeReceiveCbTimeOut(h,p->_pollPeriodMs,&readN);
return true;
}
cmSeRC_t _cmSeDestroy( cmSerialPort_t* p )
{
cmSeRC_t rc = kOkSeRC;
// stop the thread first
if( cmThreadDestroy(&p->_thH) != kOkThRC )
{
rc = cmErrMsg(&p->_err,kThreadErrSeRC,"Thread destroy failed.");
goto errLabel;
}
// Block until all written output has been sent from the device.
// Note that this call is simply passed on to the serial device driver.
// See tcsendbreak(3) ("man 3 tcsendbreak") for details.
if (tcdrain(p->_deviceH) == -1)
{
rc = cmErrSysMsg(&p->_err,kFlushFailSeRC,errno,"Error waiting for serial device '%s' to drain.", p->_deviceStr );
goto errLabel;
}
// It is good practice to reset a serial port back to the state in
// which you found it. This is why we saved the original termios struct
// The constant TCSANOW (defined in termios.h) indicates that
// the change should take effect immediately.
if (tcsetattr(p->_deviceH, TCSANOW, &p->_ttyAttrs) == -1)
{
rc = cmErrSysMsg(&p->_err,kSetAttrFailSeRC,errno,"Error resetting tty attributes on serial device '%s'.",p->_deviceStr);
goto errLabel;
}
if( p->_deviceH != -1 )
{
if( close(p->_deviceH ) != 0 )
{
rc = cmErrSysMsg(&p->_err,kCloseFailSeRC,errno,"Port close failed on serial dvice '%s'.", p->_deviceStr);
goto errLabel;
}
_cmSeSetClosedState(p);
}
cmMemPtrFree(&p);
errLabel:
return rc;
}
cmSeH_t cmSeCreate( cmCtx_t* ctx, cmSeH_t* hp, const char* deviceStr, unsigned baudRate, unsigned cfgFlags, cmSeCallbackFunc_t cbFunc, void* cbArg, unsigned pollPeriodMs )
{
cmSeRC_t rc = kOkSeRC;
struct termios options;
cmSeH_t h;
// if the port is already open then close it
if((rc = cmSeDestroy(hp)) != kOkSeRC )
return *hp;
cmSerialPort_t* p = cmMemAllocZ(cmSerialPort_t,1);
cmErrSetup(&p->_err,&ctx->rpt,"Serial Port");
p->_deviceH = -1;
// open the port
if( (p->_deviceH = open(deviceStr, O_RDWR | O_NOCTTY | O_NONBLOCK)) == -1 )
{
rc = cmErrSysMsg(&p->_err,kOpenFailSeRC,errno,"Error opening serial '%s'",cmStringNullGuard(deviceStr));
goto errLabel;;
}
// Note that open() follows POSIX semantics: multiple open() calls to
// the same file will succeed unless the TIOCEXCL ioctl is issued.
// This will prevent additional opens except by root-owned processes.
// See tty(4) ("man 4 tty") and ioctl(2) ("man 2 ioctl") for details.
if( ioctl(p->_deviceH, TIOCEXCL) == -1 )
{
rc = cmErrSysMsg(&p->_err,kResourceNotAvailableSeRC,errno,"The serial device '%s' is already in use.", cmStringNullGuard(deviceStr));
goto errLabel;
}
// Now that the device is open, clear the O_NONBLOCK flag so
// subsequent I/O will block.
// See fcntl(2) ("man 2 fcntl") for details.
/*
if (fcntl(_deviceH, F_SETFL, 0) == -1)
{
_error("Error clearing O_NONBLOCK %s - %s(%d).", pr.devFilePath.c_str(), strerror(errno), errno);
goto errLabel;
}
*/
// Get the current options and save them so we can restore the
// default settings later.
if (tcgetattr(p->_deviceH, &p->_ttyAttrs) == -1)
{
rc = cmErrSysMsg(&p->_err,kGetAttrFailSeRC,errno,"Error getting tty attributes from the device '%s'.",deviceStr);
goto errLabel;
}
// The serial port attributes such as timeouts and baud rate are set by
// modifying the termios structure and then calling tcsetattr to
// cause the changes to take effect. Note that the
// changes will not take effect without the tcsetattr() call.
// See tcsetattr(4) ("man 4 tcsetattr") for details.
options = p->_ttyAttrs;
// Set raw input (non-canonical) mode, with reads blocking until either
// a single character has been received or a 100ms timeout expires.
// See tcsetattr(4) ("man 4 tcsetattr") and termios(4) ("man 4 termios")
// for details.
cfmakeraw(&options);
options.c_cc[VMIN] = 1;
options.c_cc[VTIME] = 1;
// The baud rate, word length, and handshake options can be set as follows:
// set baud rate
cfsetspeed(&options, baudRate);
options.c_cflag |= CREAD | CLOCAL; // ignore modem controls
// set data word size
cmClrBits(options.c_cflag, CSIZE); // clear the word size bits
cmEnaBits(options.c_cflag, CS5, cmIsFlag(cfgFlags, kDataBits5SeFl));
cmEnaBits(options.c_cflag, CS6, cmIsFlag(cfgFlags, kDataBits6SeFl));
cmEnaBits(options.c_cflag, CS7, cmIsFlag(cfgFlags, kDataBits7SeFl));
cmEnaBits(options.c_cflag, CS8, cmIsFlag(cfgFlags, kDataBits8SeFl));
cmClrBits(options.c_cflag, PARENB); // assume no-parity
// if the odd or even parity flag is set
if( cmIsFlag( cfgFlags, kEvenParitySeFl) || cmIsFlag( cfgFlags, kOddParitySeFl ) )
{
cmSetBits(options.c_cflag, PARENB);
if( cmIsFlag(cfgFlags, kOddParitySeFl ) )
cmSetBits( options.c_cflag, PARODD);
}
// set two stop bits
cmEnaBits( options.c_cflag, CSTOPB, cmIsFlag(cfgFlags, k2StopBitSeFl));
// set hardware flow control
//cmEnaBits(options.c_cflag, CCTS_OFLOW, cmIsFlag(cfgFlags, kCTS_OutFlowCtlFl));
//cmEnaBits(options.c_cflag, CRTS_IFLOW, cmIsFlag(cfgFlags, kRTS_InFlowCtlFl));
//cmEnaBits(options.c_cflag, CDTR_IFLOW, cmIsFlag(cfgFlags, kDTR_InFlowCtlFl));
//cmEnaBits(options.c_cflag, CDSR_OFLOW, cmIsFlag(cfgFlags, kDSR_OutFlowCtlFl));
//cmEnaBits(options.c_cflag, CCAR_OFLOW, cmIsFlag(cfgFlags, kDCD_OutFlowCtlFl));
cmClrBits(options.c_cflag,CRTSCTS); // turn-off hardware flow control
// 7 bit words, enable even parity, CTS out ctl flow, RTS in ctl flow
// note: set PARODD and PARENB to enable odd parity)
//options.c_cflag |= (CS7 | PARENB | CCTS_OFLOW | CRTS_IFLOW );
// Cause the new options to take effect immediately.
if (tcsetattr(p->_deviceH, TCSANOW, &options) == -1)
{
rc = cmErrSysMsg(&p->_err,kSetAttrFailSeRC,errno,"Error setting tty attributes on serial device %.", deviceStr);
goto errLabel;
}
memset(&p->_pollfd,0,sizeof(p->_pollfd));
p->_pollfd.fd = p->_deviceH;
p->_pollfd.events = POLLIN;
p->_deviceStr = cmMemAllocStr( deviceStr );
p->_baudRate = baudRate;
p->_cfgFlags = cfgFlags;
p->_cbFunc = cbFunc;
p->_cbArg = cbArg;
p->_pollPeriodMs = pollPeriodMs;
// create the listening thread
if( cmThreadCreate( &p->_thH, _cmSeThreadFunc, p, &ctx->rpt) != kOkThRC )
{
rc = cmErrMsg(&p->_err,kThreadErrSeRC,"Thread initialization failed.");
goto errLabel;
}
if( cmThreadPause(p->_thH,0) != kOkThRC )
{
rc = cmErrMsg(&p->_err,kThreadErrSeRC,0,"Thread start failed.");
goto errLabel;
}
if( hp != NULL )
hp->h = p;
else
h.h = p;
errLabel:
if( rc != kOkSeRC )
{
_cmSeDestroy(p);
h.h = NULL;
}
return hp != NULL ? *hp : h;
}
cmSeRC_t cmSeDestroy(cmSeH_t* hp )
{
cmSeRC_t rc = kOkSeRC;
if( hp==NULL || !cmSeIsOpen(*hp) )
return kOkSeRC;
cmSerialPort_t* p = _cmSePtrFromHandle(*hp);
if((rc = _cmSeDestroy(p)) != kOkSeRC )
return rc;
hp->h = NULL;
return rc;
}
bool cmSeIsOpen( cmSeH_t h)
{
if( h.h == NULL )
return false;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
return p->_deviceH != -1;
}
cmSeRC_t cmSeSend( cmSeH_t h, const void* byteA, unsigned byteN )
{
cmSeRC_t rc = kOkSeRC;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
if( !cmSeIsOpen(h) )
return cmErrWarnMsg( &p->_err, kResourceNotAvailableSeRC, "An attempt was made to transmit from a closed serial port.");
if( byteN == 0 )
return rc;
// implement a non blocking write - if less than all the bytes were written then iterate
unsigned i = 0;
do
{
int n = 0;
if((n = write( p->_deviceH, ((char*)byteA)+i, byteN-i )) == -1 )
{
rc = cmErrSysMsg(&p->_err,kWriteFailSeRC,errno,"Write failed on serial port '%s'.", p->_deviceStr );
break;
}
i += n;
}while( i<byteN );
return rc;
}
cmSeRC_t cmSeReceiveCbNb( cmSeH_t h, unsigned* readN_Ref)
{
cmSeRC_t rc = kOkSeRC;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
const unsigned bufN = 512;
char buf[ bufN ];
if( readN_Ref != NULL)
*readN_Ref = 0;
if((rc = cmSeReceiveNb(h,buf,bufN,readN_Ref)) == kOkSeRC )
if( readN_Ref > 0 && p->_cbFunc != NULL )
p->_cbFunc( p->_cbArg, buf, *readN_Ref );
return rc;
}
cmSeRC_t cmSeReceiveCbTimeOut( cmSeH_t h, unsigned timeOutMs, unsigned* readN_Ref)
{
cmSeRC_t rc;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
if((rc = _cmSePoll(p,timeOutMs)) == kOkSeRC )
rc = cmSeReceiveCbNb(h,readN_Ref);
return rc;
}
cmSeRC_t cmSeReceiveNb( cmSeH_t h, void* buf, unsigned bufN, unsigned* readN_Ref)
{
cmSeRC_t rc = kOkSeRC;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
if( readN_Ref != NULL )
*readN_Ref = 0;
if( !cmSeIsOpen(h) )
return cmErrWarnMsg(&p->_err, kResourceNotAvailableSeRC, "An attempt was made to read from a closed serial port.");
int n = 0;
// if attempt to read the port succeeded ...
if((n =read( p->_deviceH, buf, bufN )) != -1 )
*readN_Ref = n;
else
{
// ... or failed and it wasn't because the port was empty
if( errno != EAGAIN)
rc = cmErrSysMsg(&p->_err,kReadFailSeRC,errno,"An attempt to read the serial port '%s' failed.", p->_deviceStr );
}
return rc;
}
cmSeRC_t cmSeReceive( cmSeH_t h, void* buf, unsigned bufByteN, unsigned timeOutMs, unsigned* readN_Ref )
{
cmSeRC_t rc = kOkSeRC;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
if((rc = _cmSePoll(p,timeOutMs)) == kOkSeRC )
rc = cmSeReceiveNb(h,buf,bufByteN,readN_Ref);
return rc;
}
const char* cmSeDevice( cmSeH_t h)
{
cmSerialPort_t* p = _cmSePtrFromHandle(h);
return p->_deviceStr;
}
unsigned cmSeBaudRate( cmSeH_t h)
{
cmSerialPort_t* p = _cmSePtrFromHandle(h);
return p->_baudRate;
}
unsigned cmSeCfgFlags( cmSeH_t h)
{
cmSerialPort_t* p = _cmSePtrFromHandle(h);
return p->_cfgFlags;
}
unsigned cmSeReadInBaudRate( cmSeH_t h )
{
struct termios attr;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
if((_cmSeGetAttributes(p,&attr)) != kOkSeRC )
return 0;
return cfgetispeed(&attr);
}
unsigned cmSeReadOutBaudRate( cmSeH_t h)
{
struct termios attr;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
if((_cmSeGetAttributes(p,&attr)) != kOkSeRC )
return 0;
return cfgetospeed(&attr);
}
unsigned cmSeReadCfgFlags( cmSeH_t h)
{
struct termios attr;
unsigned result = 0;
cmSerialPort_t* p = _cmSePtrFromHandle(h);
if((_cmSeGetAttributes(p,&attr)) == false )
return 0;
switch( attr.c_cflag & CSIZE )
{
case CS5:
cmSetBits( result, kDataBits5SeFl);
break;
case CS6:
cmSetBits( result, kDataBits6SeFl );
break;
case CS7:
cmSetBits( result, kDataBits7SeFl);
break;
case CS8:
cmSetBits( result, kDataBits8SeFl);
break;
}
cmEnaBits( result, k2StopBitSeFl, cmIsFlag( attr.c_cflag, CSTOPB ));
cmEnaBits( result, k1StopBitSeFl, !cmIsFlag( attr.c_cflag, CSTOPB ));
if( cmIsFlag( attr.c_cflag, PARENB ) )
{
cmEnaBits( result, kOddParitySeFl, cmIsFlag( attr.c_cflag, PARODD ));
cmEnaBits( result, kEvenParitySeFl, !cmIsFlag( attr.c_cflag, PARODD ));
}
return result;
}
//====================================================================================================
//
//
void _cmSePortTestCb( void* arg, const void* byteA, unsigned byteN )
{
const char* text = (const char*)byteA;
for(unsigned i=0; i<byteN; ++i)
printf("%c:%i ",text[i],(int)text[i]);
if( byteN )
fflush(stdout);
}
cmSeRC_t cmSePortTest(cmCtx_t* ctx)
{
// Use this test an Arduino running study/serial/arduino_xmt_rcv/main.c
cmSeRC_t rc = kOkSeRC;
const char* device = "/dev/ttyACM0";
unsigned baud = 38400;
unsigned serialCfgFlags = kDefaultCfgSeFlags;
unsigned pollPeriodMs = 50;
cmSeH_t h;
h.h = NULL;
h = cmSeCreate(ctx,&h,device,baud,serialCfgFlags,_cmSePortTestCb,NULL,pollPeriodMs);
bool quitFl = false;
printf("q=quit\n");
while(!quitFl)
{
char c = getchar();
if( c == 'q')
quitFl = true;
else
if( '0' <= c && c <= 'z' )
cmSeSend(h,&c,1);
}
cmSeDestroy(&h);
return rc;
}

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#ifndef cmSerialPort_h
#define cmSerialPort_h
#ifdef __cplusplus
extern "C" {
#endif
typedef unsigned cmSeRC_t;
enum
{
kOkSeRC = cmOkRC,
kFlushFailSeRC,
kSetAttrFailSeRC,
kCloseFailSeRC,
kOpenFailSeRC,
kResourceNotAvailableSeRC,
kGetAttrFailSeRC,
kWriteFailSeRC,
kReadFailSeRC,
kTimeOutSeRC,
kThreadErrSeRC
};
enum
{
kDataBits5SeFl = 0x0001,
kDataBits6SeFl = 0x0002,
kDataBits7SeFl = 0x0004,
kDataBits8SeFl = 0x0008,
kDataBitsSeMask = 0x000f,
k1StopBitSeFl = 0x0010,
k2StopBitSeFl = 0x0020,
kEvenParitySeFl = 0x0040,
kOddParitySeFl = 0x0080,
kNoParitySeFl = 0x0000,
kDefaultCfgSeFlags = kDataBits8SeFl | k1StopBitSeFl | kNoParitySeFl
};
typedef void (*cmSeCallbackFunc_t)( void* cbArg, const void* byteA, unsigned byteN );
typedef cmHandle_t cmSeH_t;
cmSeH_t cmSeCreate( cmCtx_t* ctx, cmSeH_t* hp, const char* device, unsigned baudRate, unsigned cfgFlags, cmSeCallbackFunc_t cbFunc, void* cbArg, unsigned pollPeriodMs );
cmSeRC_t cmSeDestroy(cmSeH_t* hp );
bool cmSeIsOpen( cmSeH_t h);
cmSeRC_t cmSeSend( cmSeH_t h, const void* byteA, unsigned byteN );
// Make callback to listener with result of read - Non-blocking
cmSeRC_t cmSeReceiveCbNb( cmSeH_t h, unsigned* readN_Ref);
// Make callback to listener with result of read - Block for up to timeOutMs.
cmSeRC_t cmSeReceiveCbTimeOut( cmSeH_t h, unsigned timeOutMs, unsigned* readN_Ref);
// Return result of read in buf[bufByteN] - Non-blocking.
cmSeRC_t cmSeReceiveNb( cmSeH_t h, void* buf, unsigned bufByteN, unsigned* readN_Ref);
// Return result of read in buf[bufByteN] - Block for up to timeOutMs.
cmSeRC_t cmSeReceive( cmSeH_t h, void* buf, unsigned bufByteN, unsigned timeOutMs, unsigned* readN_Ref );
const char* cmSeDevice( cmSeH_t h);
// Get the baud rate and cfgFlags used to initialize the port
unsigned cmSeBaudRate( cmSeH_t h);
unsigned cmSeCfgFlags( cmSeH_t h);
// Get the baud rate and cfg flags by reading the device.
// Note the the returned buad rate is a system id rather than the actual baud rate,
// however the cfgFlags are converted to the same kXXXFl defined in this class.
unsigned cmSeReadInBaudRate( cmSeH_t h );
unsigned cmSeReadOutBaudRate( cmSeH_t h);
unsigned cmSeReadCfgFlags( cmSeH_t h);
cmSeRC_t cmSePortTest(cmCtx_t* ctx);
#ifdef __cplusplus
}
#endif
#endif