contiki/core/lib/sensors.c

/*
 * Copyright (c) 2005, Swedish Institute of Computer Science
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 *
 * @(#)$Id: sensors.c,v 1.1 2006/06/17 22:41:18 adamdunkels Exp $
 */
/* exeperimental code, will be renamed to sensors.c when done */


#include <string.h>

#include "contiki.h"

#include "lib/sensors.h"

extern struct sensors_sensor *sensors[];
extern unsigned char sensors_flags[];
extern struct process *sensors_selecting_proc[];

#define FLAG_CHANGED    0x80

process_event_t sensors_event;

static unsigned char num_sensors;

PROCESS(sensors_process, "Sensors");

/*---------------------------------------------------------------------------*/
static int
get_sensor_index(const struct sensors_sensor *s)
{
  int i;
  for(i = 0; i < num_sensors; ++i) {
    if(sensors[i] == s) {
      return i;
    }
  }
  return i;
}
/*---------------------------------------------------------------------------*/
void
sensors_add_irq(const struct sensors_sensor *s, unsigned char irq)
{
  sensors_flags[get_sensor_index(s)] |= irq;
}
/*---------------------------------------------------------------------------*/
void
sensors_remove_irq(const struct sensors_sensor *s, unsigned char irq)
{
  sensors_flags[get_sensor_index(s)] &= ~irq;
}
/*---------------------------------------------------------------------------*/
int
sensors_handle_irq(unsigned char irq_flag)
{
  int i, w;

  w = 0;
  for(i = 0; i < num_sensors; ++i) {
    if(sensors_flags[i] & irq_flag) {
      w += sensors[i]->irq();
    }
  }
  
  return w;
}
/*---------------------------------------------------------------------------*/
struct sensors_sensor *
sensors_first(void)
{
  return sensors[0];
}
/*---------------------------------------------------------------------------*/
struct sensors_sensor *
sensors_next(const struct sensors_sensor *s)
{
  return sensors[get_sensor_index(s) + 1];
}
/*---------------------------------------------------------------------------*/
void
sensors_changed(const struct sensors_sensor *s)
{
  sensors_flags[get_sensor_index(s)] |= FLAG_CHANGED;
  process_poll(&sensors_process);
}
/*---------------------------------------------------------------------------*/
struct sensors_sensor *
sensors_find(char *prefix)
{
  int i;
  unsigned short len;
  
  /* Search through all processes and search for the specified process
     name. */
  len = strlen(prefix);
  
  for(i = 0; i < num_sensors; ++i) {
    if(strncmp(prefix, sensors[i]->type, len) == 0) {
      return sensors[i];
    }
  }
  return NULL;
}
/*---------------------------------------------------------------------------*/
#define SELCOLL ((struct process *)0x1)

void
sensors_select(const struct sensors_sensor *s, struct process *p)
{
  int i = get_sensor_index(s);

  if(sensors_selecting_proc[i] == NULL) {
    sensors_selecting_proc[i] = p;
  } else if(sensors_selecting_proc[i] == p) {
    /* If the selecting process is already registered we do nothing */
  } else {
    /* Collision, revert to broadcast! */
    sensors_selecting_proc[i] = SELCOLL;
  }
}
/*---------------------------------------------------------------------------*/
void
sensors_unselect(const struct sensors_sensor *s, const struct process *p)
{
  int i = get_sensor_index(s);

  if(sensors_selecting_proc[i] == p) {
    sensors_selecting_proc[i] = NULL;
  } else {
    /* We collided and must continue to use broadcast! */
  }
}
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(sensors_process, ev, data)
{
  int i;

  PROCESS_BEGIN();
  
  for(i = 0; sensors[i] != NULL; ++i) {
    sensors_flags[i] = 0;
    sensors[i]->init();
  }
  num_sensors = i;
  
  sensors_event = process_alloc_event();

  irq_init();

  while(1) {

    PROCESS_WAIT_EVENT();
    
    for(i = 0; i < num_sensors; ++i) {
      if(sensors_flags[i] & FLAG_CHANGED) {
	if(sensors_selecting_proc[i] == SELCOLL
	   || sensors_selecting_proc[i] == NULL)
	  process_post(PROCESS_BROADCAST, sensors_event, sensors[i]);
	else
	  process_post(sensors_selecting_proc[i], sensors_event, sensors[i]);
	sensors_flags[i] &= ~FLAG_CHANGED;
      }
    }
  }

  PROCESS_END();
}
/*---------------------------------------------------------------------------*/