libcm is a C development framework with an emphasis on audio signal processing applications.
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cmSerialPort.c 14KB

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  1. #include "cmPrefix.h"
  2. #include "cmGlobal.h"
  3. #include "cmRpt.h"
  4. #include "cmErr.h"
  5. #include "cmCtx.h"
  6. #include "cmMem.h"
  7. #include "cmMallocDebug.h"
  8. #include "cmSerialPort.h"
  9. #include "cmThread.h"
  10. #include <poll.h>
  11. #include <termios.h>
  12. #include <unistd.h> // close()
  13. #include <fcntl.h> // O_RDWR
  14. #include <sys/ioctl.h> // TIOCEXCL
  15. typedef struct cmSerialPort_str
  16. {
  17. cmErr_t _err;
  18. cmThreadH_t _thH;
  19. const char* _deviceStr;
  20. int _deviceH;
  21. unsigned _baudRate;
  22. unsigned _cfgFlags;
  23. cmSeCallbackFunc_t _cbFunc;
  24. void* _cbArg;
  25. struct termios _ttyAttrs;
  26. struct pollfd _pollfd;
  27. unsigned _pollPeriodMs;
  28. } cmSerialPort_t;
  29. cmSerialPort_t* _cmSePtrFromHandle( cmSeH_t h )
  30. {
  31. cmSerialPort_t* p = (cmSerialPort_t*)h.h;
  32. assert(p!=NULL);
  33. return p;
  34. }
  35. void _cmSeSetClosedState( cmSerialPort_t* p )
  36. {
  37. if( p->_deviceStr != NULL )
  38. cmMemFree((char*)(p->_deviceStr));
  39. p->_deviceH = -1;
  40. p->_deviceStr = NULL;
  41. p->_baudRate = 0;
  42. p->_cfgFlags = 0;
  43. p->_cbFunc = NULL;
  44. p->_cbArg = NULL;
  45. }
  46. cmSeRC_t _cmSeGetAttributes( cmSerialPort_t* p, struct termios* attr )
  47. {
  48. if( tcgetattr(p->_deviceH, attr) == -1 )
  49. return cmErrSysMsg(&p->_err,kGetAttrFailSeRC,errno,"Error getting tty attributes from %s.",p->_deviceStr);
  50. return kOkSeRC;
  51. }
  52. cmSeRC_t _cmSePoll( cmSerialPort_t* p, unsigned timeOutMs )
  53. {
  54. cmSeRC_t rc = kOkSeRC;
  55. int sysRC;
  56. if((sysRC = poll(&p->_pollfd,1,timeOutMs)) == 0)
  57. rc = kTimeOutSeRC;
  58. else
  59. {
  60. if( sysRC < 0 )
  61. rc = cmErrSysMsg(&p->_err,kReadFailSeRC,errno,"Poll failed on serial port.");
  62. }
  63. return rc;
  64. }
  65. bool _cmSeThreadFunc(void* param)
  66. {
  67. cmSerialPort_t* p = (cmSerialPort_t*)param;
  68. cmSeH_t h;
  69. h.h = p;
  70. unsigned readN;
  71. if( cmSeIsOpen(h) )
  72. cmSeReceiveCbTimeOut(h,p->_pollPeriodMs,&readN);
  73. return true;
  74. }
  75. cmSeRC_t _cmSeDestroy( cmSerialPort_t* p )
  76. {
  77. cmSeRC_t rc = kOkSeRC;
  78. // stop the thread first
  79. if( cmThreadDestroy(&p->_thH) != kOkThRC )
  80. {
  81. rc = cmErrMsg(&p->_err,kThreadErrSeRC,"Thread destroy failed.");
  82. goto errLabel;
  83. }
  84. // Block until all written output has been sent from the device.
  85. // Note that this call is simply passed on to the serial device driver.
  86. // See tcsendbreak(3) ("man 3 tcsendbreak") for details.
  87. if (tcdrain(p->_deviceH) == -1)
  88. {
  89. rc = cmErrSysMsg(&p->_err,kFlushFailSeRC,errno,"Error waiting for serial device '%s' to drain.", p->_deviceStr );
  90. goto errLabel;
  91. }
  92. // It is good practice to reset a serial port back to the state in
  93. // which you found it. This is why we saved the original termios struct
  94. // The constant TCSANOW (defined in termios.h) indicates that
  95. // the change should take effect immediately.
  96. if (tcsetattr(p->_deviceH, TCSANOW, &p->_ttyAttrs) == -1)
  97. {
  98. rc = cmErrSysMsg(&p->_err,kSetAttrFailSeRC,errno,"Error resetting tty attributes on serial device '%s'.",p->_deviceStr);
  99. goto errLabel;
  100. }
  101. if( p->_deviceH != -1 )
  102. {
  103. if( close(p->_deviceH ) != 0 )
  104. {
  105. rc = cmErrSysMsg(&p->_err,kCloseFailSeRC,errno,"Port close failed on serial dvice '%s'.", p->_deviceStr);
  106. goto errLabel;
  107. }
  108. _cmSeSetClosedState(p);
  109. }
  110. cmMemPtrFree(&p);
  111. errLabel:
  112. return rc;
  113. }
  114. cmSeH_t cmSeCreate( cmCtx_t* ctx, cmSeH_t* hp, const char* deviceStr, unsigned baudRate, unsigned cfgFlags, cmSeCallbackFunc_t cbFunc, void* cbArg, unsigned pollPeriodMs )
  115. {
  116. cmSeRC_t rc = kOkSeRC;
  117. struct termios options;
  118. cmSeH_t h;
  119. // if the port is already open then close it
  120. if((rc = cmSeDestroy(hp)) != kOkSeRC )
  121. return *hp;
  122. cmSerialPort_t* p = cmMemAllocZ(cmSerialPort_t,1);
  123. cmErrSetup(&p->_err,&ctx->rpt,"Serial Port");
  124. p->_deviceH = -1;
  125. // open the port
  126. if( (p->_deviceH = open(deviceStr, O_RDWR | O_NOCTTY | O_NONBLOCK)) == -1 )
  127. {
  128. rc = cmErrSysMsg(&p->_err,kOpenFailSeRC,errno,"Error opening serial '%s'",cmStringNullGuard(deviceStr));
  129. goto errLabel;;
  130. }
  131. // Note that open() follows POSIX semantics: multiple open() calls to
  132. // the same file will succeed unless the TIOCEXCL ioctl is issued.
  133. // This will prevent additional opens except by root-owned processes.
  134. // See tty(4) ("man 4 tty") and ioctl(2) ("man 2 ioctl") for details.
  135. if( ioctl(p->_deviceH, TIOCEXCL) == -1 )
  136. {
  137. rc = cmErrSysMsg(&p->_err,kResourceNotAvailableSeRC,errno,"The serial device '%s' is already in use.", cmStringNullGuard(deviceStr));
  138. goto errLabel;
  139. }
  140. // Now that the device is open, clear the O_NONBLOCK flag so
  141. // subsequent I/O will block.
  142. // See fcntl(2) ("man 2 fcntl") for details.
  143. /*
  144. if (fcntl(_deviceH, F_SETFL, 0) == -1)
  145. {
  146. _error("Error clearing O_NONBLOCK %s - %s(%d).", pr.devFilePath.c_str(), strerror(errno), errno);
  147. goto errLabel;
  148. }
  149. */
  150. // Get the current options and save them so we can restore the
  151. // default settings later.
  152. if (tcgetattr(p->_deviceH, &p->_ttyAttrs) == -1)
  153. {
  154. rc = cmErrSysMsg(&p->_err,kGetAttrFailSeRC,errno,"Error getting tty attributes from the device '%s'.",deviceStr);
  155. goto errLabel;
  156. }
  157. // The serial port attributes such as timeouts and baud rate are set by
  158. // modifying the termios structure and then calling tcsetattr to
  159. // cause the changes to take effect. Note that the
  160. // changes will not take effect without the tcsetattr() call.
  161. // See tcsetattr(4) ("man 4 tcsetattr") for details.
  162. options = p->_ttyAttrs;
  163. // Set raw input (non-canonical) mode, with reads blocking until either
  164. // a single character has been received or a 100ms timeout expires.
  165. // See tcsetattr(4) ("man 4 tcsetattr") and termios(4) ("man 4 termios")
  166. // for details.
  167. cfmakeraw(&options);
  168. options.c_cc[VMIN] = 1;
  169. options.c_cc[VTIME] = 1;
  170. // The baud rate, word length, and handshake options can be set as follows:
  171. // set baud rate
  172. cfsetspeed(&options, baudRate);
  173. options.c_cflag |= CREAD | CLOCAL; // ignore modem controls
  174. // set data word size
  175. cmClrBits(options.c_cflag, CSIZE); // clear the word size bits
  176. cmEnaBits(options.c_cflag, CS5, cmIsFlag(cfgFlags, kDataBits5SeFl));
  177. cmEnaBits(options.c_cflag, CS6, cmIsFlag(cfgFlags, kDataBits6SeFl));
  178. cmEnaBits(options.c_cflag, CS7, cmIsFlag(cfgFlags, kDataBits7SeFl));
  179. cmEnaBits(options.c_cflag, CS8, cmIsFlag(cfgFlags, kDataBits8SeFl));
  180. cmClrBits(options.c_cflag, PARENB); // assume no-parity
  181. // if the odd or even parity flag is set
  182. if( cmIsFlag( cfgFlags, kEvenParitySeFl) || cmIsFlag( cfgFlags, kOddParitySeFl ) )
  183. {
  184. cmSetBits(options.c_cflag, PARENB);
  185. if( cmIsFlag(cfgFlags, kOddParitySeFl ) )
  186. cmSetBits( options.c_cflag, PARODD);
  187. }
  188. // set two stop bits
  189. cmEnaBits( options.c_cflag, CSTOPB, cmIsFlag(cfgFlags, k2StopBitSeFl));
  190. // set hardware flow control
  191. //cmEnaBits(options.c_cflag, CCTS_OFLOW, cmIsFlag(cfgFlags, kCTS_OutFlowCtlFl));
  192. //cmEnaBits(options.c_cflag, CRTS_IFLOW, cmIsFlag(cfgFlags, kRTS_InFlowCtlFl));
  193. //cmEnaBits(options.c_cflag, CDTR_IFLOW, cmIsFlag(cfgFlags, kDTR_InFlowCtlFl));
  194. //cmEnaBits(options.c_cflag, CDSR_OFLOW, cmIsFlag(cfgFlags, kDSR_OutFlowCtlFl));
  195. //cmEnaBits(options.c_cflag, CCAR_OFLOW, cmIsFlag(cfgFlags, kDCD_OutFlowCtlFl));
  196. cmClrBits(options.c_cflag,CRTSCTS); // turn-off hardware flow control
  197. // 7 bit words, enable even parity, CTS out ctl flow, RTS in ctl flow
  198. // note: set PARODD and PARENB to enable odd parity)
  199. //options.c_cflag |= (CS7 | PARENB | CCTS_OFLOW | CRTS_IFLOW );
  200. // Cause the new options to take effect immediately.
  201. if (tcsetattr(p->_deviceH, TCSANOW, &options) == -1)
  202. {
  203. rc = cmErrSysMsg(&p->_err,kSetAttrFailSeRC,errno,"Error setting tty attributes on serial device %.", deviceStr);
  204. goto errLabel;
  205. }
  206. memset(&p->_pollfd,0,sizeof(p->_pollfd));
  207. p->_pollfd.fd = p->_deviceH;
  208. p->_pollfd.events = POLLIN;
  209. p->_deviceStr = cmMemAllocStr( deviceStr );
  210. p->_baudRate = baudRate;
  211. p->_cfgFlags = cfgFlags;
  212. p->_cbFunc = cbFunc;
  213. p->_cbArg = cbArg;
  214. p->_pollPeriodMs = pollPeriodMs;
  215. // create the listening thread
  216. if( cmThreadCreate( &p->_thH, _cmSeThreadFunc, p, &ctx->rpt) != kOkThRC )
  217. {
  218. rc = cmErrMsg(&p->_err,kThreadErrSeRC,"Thread initialization failed.");
  219. goto errLabel;
  220. }
  221. if( cmThreadPause(p->_thH,0) != kOkThRC )
  222. {
  223. rc = cmErrMsg(&p->_err,kThreadErrSeRC,0,"Thread start failed.");
  224. goto errLabel;
  225. }
  226. if( hp != NULL )
  227. hp->h = p;
  228. else
  229. h.h = p;
  230. errLabel:
  231. if( rc != kOkSeRC )
  232. {
  233. _cmSeDestroy(p);
  234. h.h = NULL;
  235. }
  236. return hp != NULL ? *hp : h;
  237. }
  238. cmSeRC_t cmSeDestroy(cmSeH_t* hp )
  239. {
  240. cmSeRC_t rc = kOkSeRC;
  241. if( hp==NULL || !cmSeIsOpen(*hp) )
  242. return kOkSeRC;
  243. cmSerialPort_t* p = _cmSePtrFromHandle(*hp);
  244. if((rc = _cmSeDestroy(p)) != kOkSeRC )
  245. return rc;
  246. hp->h = NULL;
  247. return rc;
  248. }
  249. bool cmSeIsOpen( cmSeH_t h)
  250. {
  251. if( h.h == NULL )
  252. return false;
  253. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  254. return p->_deviceH != -1;
  255. }
  256. cmSeRC_t cmSeSend( cmSeH_t h, const void* byteA, unsigned byteN )
  257. {
  258. cmSeRC_t rc = kOkSeRC;
  259. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  260. if( !cmSeIsOpen(h) )
  261. return cmErrWarnMsg( &p->_err, kResourceNotAvailableSeRC, "An attempt was made to transmit from a closed serial port.");
  262. if( byteN == 0 )
  263. return rc;
  264. // implement a non blocking write - if less than all the bytes were written then iterate
  265. unsigned i = 0;
  266. do
  267. {
  268. int n = 0;
  269. if((n = write( p->_deviceH, ((char*)byteA)+i, byteN-i )) == -1 )
  270. {
  271. rc = cmErrSysMsg(&p->_err,kWriteFailSeRC,errno,"Write failed on serial port '%s'.", p->_deviceStr );
  272. break;
  273. }
  274. i += n;
  275. }while( i<byteN );
  276. return rc;
  277. }
  278. cmSeRC_t cmSeReceiveCbNb( cmSeH_t h, unsigned* readN_Ref)
  279. {
  280. cmSeRC_t rc = kOkSeRC;
  281. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  282. const unsigned bufN = 512;
  283. char buf[ bufN ];
  284. if( readN_Ref != NULL)
  285. *readN_Ref = 0;
  286. if((rc = cmSeReceiveNb(h,buf,bufN,readN_Ref)) == kOkSeRC )
  287. if( readN_Ref > 0 && p->_cbFunc != NULL )
  288. p->_cbFunc( p->_cbArg, buf, *readN_Ref );
  289. return rc;
  290. }
  291. cmSeRC_t cmSeReceiveCbTimeOut( cmSeH_t h, unsigned timeOutMs, unsigned* readN_Ref)
  292. {
  293. cmSeRC_t rc;
  294. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  295. if((rc = _cmSePoll(p,timeOutMs)) == kOkSeRC )
  296. rc = cmSeReceiveCbNb(h,readN_Ref);
  297. return rc;
  298. }
  299. cmSeRC_t cmSeReceiveNb( cmSeH_t h, void* buf, unsigned bufN, unsigned* readN_Ref)
  300. {
  301. cmSeRC_t rc = kOkSeRC;
  302. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  303. if( readN_Ref != NULL )
  304. *readN_Ref = 0;
  305. if( !cmSeIsOpen(h) )
  306. return cmErrWarnMsg(&p->_err, kResourceNotAvailableSeRC, "An attempt was made to read from a closed serial port.");
  307. int n = 0;
  308. // if attempt to read the port succeeded ...
  309. if((n =read( p->_deviceH, buf, bufN )) != -1 )
  310. *readN_Ref = n;
  311. else
  312. {
  313. // ... or failed and it wasn't because the port was empty
  314. if( errno != EAGAIN)
  315. rc = cmErrSysMsg(&p->_err,kReadFailSeRC,errno,"An attempt to read the serial port '%s' failed.", p->_deviceStr );
  316. }
  317. return rc;
  318. }
  319. cmSeRC_t cmSeReceive( cmSeH_t h, void* buf, unsigned bufByteN, unsigned timeOutMs, unsigned* readN_Ref )
  320. {
  321. cmSeRC_t rc = kOkSeRC;
  322. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  323. if((rc = _cmSePoll(p,timeOutMs)) == kOkSeRC )
  324. rc = cmSeReceiveNb(h,buf,bufByteN,readN_Ref);
  325. return rc;
  326. }
  327. const char* cmSeDevice( cmSeH_t h)
  328. {
  329. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  330. return p->_deviceStr;
  331. }
  332. unsigned cmSeBaudRate( cmSeH_t h)
  333. {
  334. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  335. return p->_baudRate;
  336. }
  337. unsigned cmSeCfgFlags( cmSeH_t h)
  338. {
  339. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  340. return p->_cfgFlags;
  341. }
  342. unsigned cmSeReadInBaudRate( cmSeH_t h )
  343. {
  344. struct termios attr;
  345. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  346. if((_cmSeGetAttributes(p,&attr)) != kOkSeRC )
  347. return 0;
  348. return cfgetispeed(&attr);
  349. }
  350. unsigned cmSeReadOutBaudRate( cmSeH_t h)
  351. {
  352. struct termios attr;
  353. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  354. if((_cmSeGetAttributes(p,&attr)) != kOkSeRC )
  355. return 0;
  356. return cfgetospeed(&attr);
  357. }
  358. unsigned cmSeReadCfgFlags( cmSeH_t h)
  359. {
  360. struct termios attr;
  361. unsigned result = 0;
  362. cmSerialPort_t* p = _cmSePtrFromHandle(h);
  363. if((_cmSeGetAttributes(p,&attr)) == false )
  364. return 0;
  365. switch( attr.c_cflag & CSIZE )
  366. {
  367. case CS5:
  368. cmSetBits( result, kDataBits5SeFl);
  369. break;
  370. case CS6:
  371. cmSetBits( result, kDataBits6SeFl );
  372. break;
  373. case CS7:
  374. cmSetBits( result, kDataBits7SeFl);
  375. break;
  376. case CS8:
  377. cmSetBits( result, kDataBits8SeFl);
  378. break;
  379. }
  380. cmEnaBits( result, k2StopBitSeFl, cmIsFlag( attr.c_cflag, CSTOPB ));
  381. cmEnaBits( result, k1StopBitSeFl, !cmIsFlag( attr.c_cflag, CSTOPB ));
  382. if( cmIsFlag( attr.c_cflag, PARENB ) )
  383. {
  384. cmEnaBits( result, kOddParitySeFl, cmIsFlag( attr.c_cflag, PARODD ));
  385. cmEnaBits( result, kEvenParitySeFl, !cmIsFlag( attr.c_cflag, PARODD ));
  386. }
  387. return result;
  388. }
  389. //====================================================================================================
  390. //
  391. //
  392. void _cmSePortTestCb( void* arg, const void* byteA, unsigned byteN )
  393. {
  394. const char* text = (const char*)byteA;
  395. for(unsigned i=0; i<byteN; ++i)
  396. printf("%c:%i ",text[i],(int)text[i]);
  397. if( byteN )
  398. fflush(stdout);
  399. }
  400. cmSeRC_t cmSePortTest(cmCtx_t* ctx)
  401. {
  402. // Use this test an Arduino running study/serial/arduino_xmt_rcv/main.c
  403. cmSeRC_t rc = kOkSeRC;
  404. const char* device = "/dev/ttyACM0";
  405. unsigned baud = 38400;
  406. unsigned serialCfgFlags = kDefaultCfgSeFlags;
  407. unsigned pollPeriodMs = 50;
  408. cmSeH_t h;
  409. h.h = NULL;
  410. h = cmSeCreate(ctx,&h,device,baud,serialCfgFlags,_cmSePortTestCb,NULL,pollPeriodMs);
  411. bool quitFl = false;
  412. printf("q=quit\n");
  413. while(!quitFl)
  414. {
  415. char c = getchar();
  416. if( c == 'q')
  417. quitFl = true;
  418. else
  419. if( '0' <= c && c <= 'z' )
  420. cmSeSend(h,&c,1);
  421. }
  422. cmSeDestroy(&h);
  423. return rc;
  424. }