sample1.c

运行于T-Engine(使用T-Kernel操作系统)的实例源码

/*
 * sample1.c - a sample application which uses a serial port
 *
 * Copyright (C) YRP Ubiquitous Networking Laboratory, 2005.
 */

#include <basic.h>
#include <string.h>
#include <tk/tkernel.h>
#include <device/rs.h>
#include "calc.h"

#define EXIT_COMMAND    "EXIT"
#define ERROR_MESSAGE   "Error!\n"

LOCAL INT exit_flag;
#define RBUFLEN         256
#define SBUFLEN         256
LOCAL UB rbuf[RBUFLEN];
LOCAL UB sbuf[SBUFLEN];

LOCAL ER set_serial_params(ID dd, RsMode *mode, RsFlow *flow)
{
  INT asize;
  ER ercd;

  if (dd < 0 || mode == NULL || flow == NULL) {
    return E_PAR;
  }

  /* set communication mode */
  ercd = tk_swri_dev(dd, DN_RSMODE, mode, sizeof(RsMode), &asize);
  if (ercd < E_OK) { return ercd; }

  /* set flow control */
  ercd = tk_swri_dev(dd, DN_RSFLOW, flow, sizeof(RsFlow), &asize);
  if (ercd < E_OK) { return ercd; }

  return E_OK;
}

LOCAL ER read_command(ID dd, UB *buf, INT *len)
{
  ER ercd;
  INT i, asize;

  for (i = 0; i < *len; i++) {
    ercd = tk_srea_dev(dd, 0, buf+i, 1, &asize);
    if (ercd < E_OK) {
      return ercd;
    }
    /* check if input is complete */
    if (*(rbuf+i) == '\n') {
      *(rbuf+i) = '\0';         /* replace LF with a null character */
      break;
    }
  }
  if (i == *len) {
    /* buffer is full. force terminating the string. */
    *(rbuf+i-1) = '\0';
  }
  *len = i-1;

  return E_OK;
}

LOCAL ER send_reply(ID dd, UB *buf, INT len)
{
  ER ercd;
  INT rest, asize;

  rest = len;
  while (rest > 0) {
    ercd = tk_swri_dev(dd, 0, buf+len-rest, rest, &asize);
    if (ercd < E_OK) {
      return ercd;
    }
    rest -= asize;
  }

  return E_OK;
}

EXPORT void tet_exit(void)
{
  exit_flag = 1;
}

EXPORT void tet_task(INT stacd, VP exinf)
{
  UB devnm[8];
  ID ptid, dd_rs;
  RsMode mode;
  RsFlow flow;
  ER ercd;

  /* get the parent's task ID from an argument */
  ptid = (ID) stacd;

  /* open the RS (serial) driver */
  strcpy(devnm, "vrsa");
  dd_rs = tk_opn_dev(devnm, TD_UPDATE | TD_EXCL); /* open the device */
  if (dd_rs < E_OK) { goto EXIT; }      /* open error */

  /* port settings */
  mode.parity   = 0;            /* parity: none        */
  mode.datalen  = 3;            /* data length: 8 bit  */
  mode.stopbits = 0;            /* stop bits: 1        */
  mode.rsv      = 0;            /* reserved (not used) */
  mode.baud     = 38400;        /* baud rate: 38400    */

  flow.rsv     = 0;             /* reserved (not used)               */
  flow.rcvxoff = 0;             /* XOFF: no                          */
  flow.csflow  = 0;             /* CTS flow control: no              */
  flow.rsflow  = 0;             /* RTS flow control: no              */
  flow.xonany  = 0;             /* XON with any character: no        */
  flow.sxflow  = 0;             /* XON/XOFF control in sending: no   */
  flow.rxflow  = 0;             /* XON/XOFF control in receiving: no */

  ercd = set_serial_params(dd_rs, &mode, &flow);
  if (ercd != E_OK) { goto EXIT; }      /* error in setting parameters */

  /* main loop until exit_flag is on */
  exit_flag = 0;
  while (exit_flag == 0) {
    INT rlen, slen;

    rlen = RBUFLEN;
    ercd = read_command(dd_rs, rbuf, &rlen);
    if (ercd != E_OK) {
      continue;
    }

    if (strcmp(rbuf, EXIT_COMMAND) == 0) {
      tet_exit();
      continue;
    }

    ercd = tet_calc(rbuf, sbuf);
    if (ercd != E_OK) {
      /* set error message */
      strcpy(sbuf, ERROR_MESSAGE);
    }

    slen = strlen(sbuf);
    ercd = send_reply(dd_rs, sbuf, slen);
  }

  /* close the RS driver */
  ercd = tk_cls_dev(dd_rs, 0);
  if (ercd < E_OK) { goto EXIT; }       /* close error */

EXIT:
  /* wake up the parent */
  tk_wup_tsk(ptid);
  /* stop and remove this task */
  tk_exd_tsk();
}