osd-contiki/core/sys/process.h

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/*
* 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: process.h,v 1.9 2007/08/22 10:49:48 ksb Exp $
*/
/**
* \addtogroup sys
* @{
*/
/**
* \defgroup process Contiki processes
*
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* A process in Contiki consists of a single \ref pt "protothread".
*
* @{
*/
/**
* \file
* Header file for the Contiki process interface.
* \author
* Adam Dunkels <adam@sics.se>
*
*/
#ifndef __PROCESS_H__
#define __PROCESS_H__
#include "sys/pt.h"
#include "sys/cc.h"
typedef unsigned char process_event_t;
typedef void * process_data_t;
typedef unsigned char process_num_events_t;
/**
* \name Return values
* @{
*/
/**
* \brief Return value indicating that an operation was successful.
*
* This value is returned to indicate that an operation
* was successful.
*/
#define PROCESS_ERR_OK 0
/**
* \brief Return value indicating that the event queue was full.
*
* This value is returned from process_post() to indicate
* that the event queue was full and that an event could
* not be posted.
*/
#define PROCESS_ERR_FULL 1
/* @} */
#define PROCESS_NONE NULL
#ifndef PROCESS_CONF_NUMEVENTS
#define PROCESS_CONF_NUMEVENTS 32
#endif /* PROCESS_CONF_NUMEVENTS */
#define PROCESS_EVENT_NONE 0x80
#define PROCESS_EVENT_INIT 0x81
#define PROCESS_EVENT_POLL 0x82
#define PROCESS_EVENT_EXIT 0x83
#define PROCESS_EVENT_SERVICE_REMOVED 0x84
#define PROCESS_EVENT_CONTINUE 0x85
#define PROCESS_EVENT_MSG 0x86
#define PROCESS_EVENT_EXITED 0x87
#define PROCESS_EVENT_TIMER 0x88
#define PROCESS_EVENT_COM 0x89
#define PROCESS_EVENT_MAX 0x8a
#define PROCESS_BROADCAST NULL
#define PROCESS_ZOMBIE ((struct process *)0x1)
/**
* \name Process protothread functions
* @{
*/
/**
* Define the beginning of a process.
*
* This macro defines the beginning of a process, and must always
* appear in a PROCESS_THREAD() definition. The PROCESS_END() macro
* must come at the end of the process.
*
* \hideinitializer
*/
#define PROCESS_BEGIN() PT_BEGIN(process_pt)
/**
* Define the end of a process.
*
* This macro defines the end of a process. It must appear in a
* PROCESS_THREAD() definition and must always be included. The
* process exits when the PROCESS_END() macro is reached.
*
* \hideinitializer
*/
#define PROCESS_END() PT_END(process_pt)
/**
* Wait for an event to be posted to the process.
*
* This macro blocks the currently running process until the process
* receives an event.
*
* \hideinitializer
*/
#define PROCESS_WAIT_EVENT() PROCESS_YIELD()
/**
* Wait for an event to be posted to the process, with an extra
* condition.
*
* This macro is similar to PROCESS_WAIT_EVENT() in that it blocks the
* currently running process until the process receives an event. But
* PROCESS_WAIT_EVENT_UNTIL() takes an extra condition which must be
* true for the process to continue.
*
* \param c The condition that must be true for the process to continue.
* \sa PT_WAIT_UNTIL()
*
* \hideinitializer
*/
#define PROCESS_WAIT_EVENT_UNTIL(c) PROCESS_YIELD_UNTIL(c)
/**
* Yield the currently running process.
*
* \hideinitializer
*/
#define PROCESS_YIELD() PT_YIELD(process_pt)
/**
* Yield the currently running process until a condition occurs.
*
* This macro is different from PROCESS_WAIT_UNTIL() in that
* PROCESS_YIELD_UNTIL() is guaranteed to always yield at least
* once. This ensures that the process does not end up in an infinite
* loop and monopolizing the CPU.
*
* \param c The condition to wait for.
*
* \hideinitializer
*/
#define PROCESS_YIELD_UNTIL(c) PT_YIELD_UNTIL(process_pt, c)
/**
* Wait for a condition to occur.
*
* This macro does not guarantee that the process yields, and should
* therefore be used with care. In most cases, PROCESS_WAIT_EVENT(),
* PROCESS_WAIT_EVENT_UNTIL(), PROCESS_YIELD() or
* PROCESS_YIELD_UNTIL() should be used instead.
*
* \param c The condition to wait for.
*
* \hideinitializer
*/
#define PROCESS_WAIT_UNTIL(c) PT_WAIT_UNTIL(process_pt, c)
#define PROCESS_WAIT_WHILE(c) PT_WAIT_WHILE(process_pt, c)
/**
* Exit the currently running process.
*
* \hideinitializer
*/
#define PROCESS_EXIT() PT_EXIT(process_pt)
/**
* Spawn a protothread from the process.
*
* \param pt The protothread state (struct pt) for the new protothread
* \param thread The call to the protothread function.
* \sa PT_SPAWN()
*
* \hideinitializer
*/
#define PROCESS_PT_SPAWN(pt, thread) PT_SPAWN(process_pt, pt, thread)
/**
* Yield the process for a short while.
*
* This macro yields the currently running process for a short while,
* thus letting other processes run before the process continues.
*
* \hideinitializer
*/
#define PROCESS_PAUSE() do { \
process_post(PROCESS_CURRENT(), PROCESS_EVENT_CONTINUE, NULL); \
PROCESS_WAIT_EVENT(); \
} while(0)
/** @} end of protothread functions */
/**
* \name Poll and exit handlers
* @{
*/
/**
* Specify an action when a process is polled.
*
* \note This declaration must come immediately before the
* PROCESS_BEGIN() macro.
*
* \param handler The action to be performed.
*
* \hideinitializer
*/
#define PROCESS_POLLHANDLER(handler) if(ev == PROCESS_EVENT_POLL) { handler; }
/**
* Specify an action when a process exits.
*
* \note This declaration must come immediately before the
* PROCESS_BEGIN() macro.
*
* \param handler The action to be performed.
*
* \hideinitializer
*/
#define PROCESS_EXITHANDLER(handler) if(ev == PROCESS_EVENT_EXIT) { handler; }
/** @} */
/**
* \name Process declaration and definion
* @{
*/
/**
* Define the body of a process.
*
* This macro is used to define the body (protothread) of a
* process. The process is called whenever an event occurs in the
* system, A process always start with the PROCESS_BEGIN() macro and
* end with the PROCESS_END() macro.
*
* \hideinitializer
*/
#define PROCESS_THREAD(name, ev, data) \
static PT_THREAD(process_thread_##name(struct pt *process_pt, \
process_event_t ev, \
process_data_t data))
#if PROCESS_LOADABLE
#define PROCESS_LOAD(name) const struct process *process_load = &name
#else /* PROCESS_LOADABLE */
#define PROCESS_LOAD(name) extern int _dummy
#endif /* PROCESS_LOADABLE */
CLIF extern const struct process *process_load;
/**
* Declare the name of a process.
*
* This macro is typically used in header files to declare the name of
* a process that is implemented in the C file.
*
* \hideinitializer
*/
#define PROCESS_NAME(name) extern struct process name
#define PROCESS_NOLOAD(name, strname) \
PROCESS_THREAD(name, ev, data); \
struct process name = { NULL, strname, \
process_thread_##name }
/**
* Declare a process.
*
* This macro declares a process. The process has two names: the
* variable of the process structure, which is used by the C program,
* and a human readable string name, which is used when debugging.
*
* \param name The variable name of the process structure.
* \param strname The string repressentation of the process' name.
*
* \hideinitializer
*/
#define PROCESS(name, strname) \
PROCESS_NOLOAD(name, strname); \
PROCESS_LOAD(name)
/** @} */
struct process {
struct process *next;
const char *name;
PT_THREAD((* thread)(struct pt *, process_event_t, process_data_t));
struct pt pt;
unsigned char state;
};
/**
* \name Functions called from application programs
* @{
*/
/**
* Start a process.
*
* \param p A pointer to a process structure.
*
* \param arg An argument pointer that can be passed to the new
* process
*
*/
void process_start(struct process *p, char *arg);
/**
* Post an asynchronous event.
*
* This function posts an asynchronous event to one or more
* processes. The handing of the event is deferred until the target
* process is scheduled by the kernel. An event can be broadcast to
* all processes, in which case all processes in the system will be
* scheduled to handle the event.
*
* \param ev The event to be posted.
*
* \param data The auxillary data to be sent with the event
*
* \param p The process to which the event should be posted, or
* PROCESS_BROADCAST if the event should be posted to all processes.
*
* \retval PROCESS_ERR_OK The event could be posted.
*
* \retval PROCESS_ERR_FULL The event queue was full and the event could
* not be posted.
*/
CCIF int process_post(struct process *p, process_event_t ev, process_data_t data);
/**
* Post a synchronous event to a process.
*
* \param p A pointer to the process' process structure.
*
* \param ev The event to be posted.
*
* \param data A pointer to additional data that is posted together
* with the event.
*/
void process_post_synch(struct process *p,
process_event_t ev, process_data_t data);
/**
* \brief Cause a process to exit
* \param p The process that is to be exited
*
* This function causes a process to exit. The process can
* either be the currently executing process, or another
* process that is currently running.
*
* \sa PROCESS_CURRENT()
*/
CCIF void process_exit(struct process *p);
/**
* Get a pointer to the currently running process.
*
* This macro get a pointer to the currently running
* process. Typically, this macro is used to post an event to the
* current process with process_post().
*
* \hideinitializer
*/
#define PROCESS_CURRENT() process_current
CCIF extern struct process *process_current;
/**
* Switch context to another process
*
* This function switch context to the specified process and executes
* the code as if run by that process. Typical use of this function is
* to switch context in services, called by other processes. Each
* PROCESS_CONTEXT_BEGIN() must be followed by the
* PROCESS_CONTEXT_END() macro to end the context switch.
*
* Example:
\code
PROCESS_CONTEXT_BEGIN(&test_process);
etimer_set(&timer, CLOCK_SECOND);
PROCESS_CONTEXT_END(&test_process);
\endcode
*
* \param p The process to use as context
*
* \sa PROCESS_CONTEXT_END()
* \sa PROCESS_CURRENT()
*/
#define PROCESS_CONTEXT_BEGIN(p) {\
struct process *tmp_current = PROCESS_CURRENT();\
process_current = p
/**
* End a context switch
*
* This function ends a context switch and changes back to the
* previous process.
*
* \param p The process used in the context switch
*
* \sa PROCESS_CONTEXT_START()
*/
#define PROCESS_CONTEXT_END(p) process_current = tmp_current; }
/**
* \brief Allocate a global event number.
* \return The allocated event number
*
* In Contiki, event numbers above 128 are global and may
* be posted from one process to another. This function
* allocates one such event number.
*
* \note There currently is no way to deallocate an allocated event
* number.
*/
process_event_t process_alloc_event(void);
/** @} */
/**
* \name Functions called from device drivers
* @{
*/
/**
* Request a process to be polled.
*
* This function typically is called from an interrupt handler to
* cause a process to be polled.
*
* \param p A pointer to the process' process structure.
*/
CCIF void process_poll(struct process *p);
/** @} */
/**
* \name Functions called by the system and boot-up code
* @{
*/
/**
* \brief Initialize the process module.
*
* This function initializes the process module and should
* be called by the system boot-up code.
*/
void process_init(void);
/**
* Run the system once - call poll handlers and process one event.
*
* This function should be called repeatedly from the main() program
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* to actually run the Contiki system. It calls the necessary poll
* handlers, and processes one event. The function returns the number
* of events that are waiting in the event queue so that the caller
* may choose to put the CPU to sleep when there are no pending
* events.
*
* \return The number of events that are currently waiting in the
* event queue.
*/
int process_run(void);
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/**
* Number of events waiting to be processed.
*
* \return The number of events that are currently waiting to be
* processed.
*/
int process_nevents(void);
/** @} */
CCIF extern struct process *process_list;
#define PROCESS_LIST() process_list
#endif /* __PROCESS_H__ */
/** @} */
/** @} */