Contiki 2.6

serial-line.c

00001 /*
00002  * Copyright (c) 2005, Swedish Institute of Computer Science
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the Institute nor the names of its contributors
00014  *    may be used to endorse or promote products derived from this software
00015  *    without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  *
00029  * This file is part of the Contiki operating system.
00030  *
00031  * @(#)$Id: serial-line.c,v 1.4 2010/02/23 18:26:26 adamdunkels Exp $
00032  */
00033 #include "dev/serial-line.h"
00034 #include <string.h> /* for memcpy() */
00035 
00036 #include "lib/ringbuf.h"
00037 
00038 #ifdef SERIAL_LINE_CONF_BUFSIZE
00039 #define BUFSIZE SERIAL_LINE_CONF_BUFSIZE
00040 #else /* SERIAL_LINE_CONF_BUFSIZE */
00041 #define BUFSIZE 128
00042 #endif /* SERIAL_LINE_CONF_BUFSIZE */
00043 
00044 #if (BUFSIZE & (BUFSIZE - 1)) != 0
00045 #error SERIAL_LINE_CONF_BUFSIZE must be a power of two (i.e., 1, 2, 4, 8, 16, 32, 64, ...).
00046 #error Change SERIAL_LINE_CONF_BUFSIZE in contiki-conf.h.
00047 #endif
00048 
00049 #define IGNORE_CHAR(c) (c == 0x0d)
00050 #define END 0x0a
00051 
00052 static struct ringbuf rxbuf;
00053 static uint8_t rxbuf_data[BUFSIZE];
00054 
00055 PROCESS(serial_line_process, "Serial driver");
00056 
00057 process_event_t serial_line_event_message;
00058 
00059 /*---------------------------------------------------------------------------*/
00060 int
00061 serial_line_input_byte(unsigned char c)
00062 {
00063   static uint8_t overflow = 0; /* Buffer overflow: ignore until END */
00064   
00065   if(IGNORE_CHAR(c)) {
00066     return 0;
00067   }
00068 
00069   if(!overflow) {
00070     /* Add character */
00071     if(ringbuf_put(&rxbuf, c) == 0) {
00072       /* Buffer overflow: ignore the rest of the line */
00073       overflow = 1;
00074     }
00075   } else {
00076     /* Buffer overflowed:
00077      * Only (try to) add terminator characters, otherwise skip */
00078     if(c == END && ringbuf_put(&rxbuf, c) != 0) {
00079       overflow = 0;
00080     }
00081   }
00082 
00083   /* Wake up consumer process */
00084   process_poll(&serial_line_process);
00085   return 1;
00086 }
00087 /*---------------------------------------------------------------------------*/
00088 PROCESS_THREAD(serial_line_process, ev, data)
00089 {
00090   static char buf[BUFSIZE];
00091   static int ptr;
00092 
00093   PROCESS_BEGIN();
00094 
00095   serial_line_event_message = process_alloc_event();
00096   ptr = 0;
00097 
00098   while(1) {
00099     /* Fill application buffer until newline or empty */
00100     int c = ringbuf_get(&rxbuf);
00101     
00102     if(c == -1) {
00103       /* Buffer empty, wait for poll */
00104       PROCESS_YIELD();
00105     } else {
00106       if(c != END) {
00107         if(ptr < BUFSIZE-1) {
00108           buf[ptr++] = (uint8_t)c;
00109         } else {
00110           /* Ignore character (wait for EOL) */
00111         }
00112       } else {
00113         /* Terminate */
00114         buf[ptr++] = (uint8_t)'\0';
00115 
00116         /* Broadcast event */
00117         process_post(PROCESS_BROADCAST, serial_line_event_message, buf);
00118 
00119         /* Wait until all processes have handled the serial line event */
00120         if(PROCESS_ERR_OK ==
00121           process_post(PROCESS_CURRENT(), PROCESS_EVENT_CONTINUE, NULL)) {
00122           PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_CONTINUE);
00123         }
00124         ptr = 0;
00125       }
00126     }
00127   }
00128 
00129   PROCESS_END();
00130 }
00131 /*---------------------------------------------------------------------------*/
00132 void
00133 serial_line_init(void)
00134 {
00135   ringbuf_init(&rxbuf, rxbuf_data, sizeof(rxbuf_data));
00136   process_start(&serial_line_process, NULL);
00137 }
00138 /*---------------------------------------------------------------------------*/