LUFA/Scheduler/Scheduler.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Simple round-robbin cooperative scheduler for use in basic projects where non real-time tasks need
  34  *  to be executed. Each task is executed in sequence, and can be enabled or disabled individually or as a group.
  35  *
  36  *  \deprecated This module is deprecated and will be removed in a future library release.
  37  */
  38
  39 /** @defgroup Group_Scheduler Simple Task Scheduler - LUFA/Scheduler/Scheduler.h
  40  *
  41  *  \deprecated This module is deprecated and will be removed in a future library release.
  42  *
  43  *  \section Sec_Dependencies Module Source Dependencies
  44  *  The following files must be built with any user project that uses this module:
  45  *    - LUFA/Scheduler/Scheduler.c
  46  *
  47  *  \section Module Description
  48  *  Simple round-robbin cooperative scheduler for use in basic projects where non real-time tasks need
  49  *  to be executed. Each task is executed in sequence, and can be enabled or disabled individually or as a group.
  50  *
  51  *  For a task to yield it must return, thus each task should have persistent data marked with the static attribute.
  52  *
  53  *  Usage Example:
  54  *  \code
  55  *      #include <LUFA/Scheduler/Scheduler.h>
  56  *
  57  *      TASK(MyTask1);
  58  *      TASK(MyTask2);
  59  *
  60  *      TASK_LIST
  61  *      {
  62  *              { .Task = MyTask1, .TaskStatus = TASK_RUN, .GroupID = 1  },
  63  *              { .Task = MyTask2, .TaskStatus = TASK_RUN, .GroupID = 1  },
  64  *      }
  65  *
  66  *      int main(void)
  67  *      {
  68  *              Scheduler_Start();
  69  *      }
  70  *
  71  *      TASK(MyTask1)
  72  *      {
  73  *              // Implementation Here
  74  *      }
  75  *
  76  *      TASK(MyTask2)
  77  *      {
  78  *              // Implementation Here
  79  *      }
  80  *  \endcode
  81  *
  82  *  @{
  83  */
  84
  85 #ifndef __SCHEDULER_H__
  86 #define __SCHEDULER_H__
  87
  88         /* Includes: */
  89                 #include <avr/io.h>
  90                 #include <stdbool.h>
  91
  92                 #include <util/atomic.h>
  93
  94                 #include "../Common/Common.h"
  95
  96         /* Enable C linkage for C++ Compilers: */
  97                 #if defined(__cplusplus)
  98                         extern "C" {
  99                 #endif
 100
 101         /* Public Interface - May be used in end-application: */
 102                 /* Macros: */
 103                         /** Creates a new scheduler task body or prototype. Should be used in the form:
 104                          *  \code
 105                          *      TASK(TaskName); // Prototype
 106                          *
 107                          *      TASK(TaskName)
 108                          *      {
 109                          *           // Task body
 110                          *      }
 111                          *  \endcode
 112                          */
 113                         #define TASK(name)                        void name (void)
 114
 115                         /** Defines a task list array, containing one or more task entries of the type TaskEntry_t. Each task list
 116                          *  should be encased in curly braces and ended with a comma.
 117                          *
 118                          *  Usage Example:
 119                          *  \code
 120                          *      TASK_LIST
 121                          *      {
 122                          *           { .Task = MyTask1, .TaskStatus = TASK_RUN, .GroupID = 1 },
 123                          *           // More task entries here
 124                          *      }
 125                          *  \endcode
 126                          */
 127                         #define TASK_LIST                         TaskEntry_t Scheduler_TaskList[] =
 128
 129                         /** Constant, giving the maximum delay in scheduler ticks which can be stored in a variable of type
 130                          *  SchedulerDelayCounter_t.
 131                          */
 132                         #define TASK_MAX_DELAY                    (MAX_DELAYCTR_COUNT - 1)
 133
 134                         /** Task status mode constant, for passing to Scheduler_SetTaskMode() or Scheduler_SetGroupTaskMode(). */
 135                         #define TASK_RUN                          true
 136
 137                         /** Task status mode constant, for passing to Scheduler_SetTaskMode() or Scheduler_SetGroupTaskMode(). */
 138                         #define TASK_STOP                         false
 139
 140                 /* Pseudo-Function Macros: */
 141                         #if defined(__DOXYGEN__)
 142                                 /** Starts the scheduler in its infinite loop, executing running tasks. This should be placed at the end
 143                                  *  of the user application's main() function, as it can never return to the calling function.
 144                                  */
 145                                 void Scheduler_Start(void);
 146
 147                                 /** Initializes the scheduler so that the scheduler functions can be called before the scheduler itself
 148                                  *  is started. This must be executed before any scheduler function calls other than Scheduler_Start(),
 149                                  *  and can be omitted if no such functions could be called before the scheduler is started.
 150                                  */
 151                                 void Scheduler_Init(void);
 152                         #else
 153                                 #define Scheduler_Start()                 Scheduler_GoSchedule(TOTAL_TASKS);
 154
 155                                 #define Scheduler_Init()                  Scheduler_InitScheduler(TOTAL_TASKS);
 156                         #endif
 157
 158                 /* Type Defines: */
 159                         /** Type define for a pointer to a scheduler task. */
 160                         typedef void (*TaskPtr_t)(void);
 161
 162                         /** Type define for a variable which can hold a tick delay value for the scheduler up to the maximum delay
 163                          *  possible.
 164                          */
 165                         typedef uint16_t SchedulerDelayCounter_t;
 166
 167                         /** Structure for holding a single task's information in the scheduler task list. */
 168                         typedef struct
 169                         {
 170                                 TaskPtr_t Task;       /**< Pointer to the task to execute. */
 171                                 bool      TaskStatus; /**< Status of the task (either TASK_RUN or TASK_STOP). */
 172                                 uint8_t   GroupID;    /**< Group ID of the task so that its status can be changed as a group. */
 173                         } TaskEntry_t;
 174
 175                 /* Global Variables: */
 176                         /** Task entry list, containing the scheduler tasks, task statuses and group IDs. Each entry is of type
 177                          *  TaskEntry_t and can be manipulated as desired, although it is preferential that the proper Scheduler
 178                          *  functions should be used instead of direct manipulation.
 179                          */
 180                         extern          TaskEntry_t               Scheduler_TaskList[];
 181
 182                         /** Contains the total number of tasks in the task list, irrespective of if the task's status is set to
 183                          *  TASK_RUN or TASK_STOP.
 184                          *
 185                          *  \note This value should be treated as read-only, and never altered in user-code.
 186                          */
 187                         extern volatile uint8_t                   Scheduler_TotalTasks;
 188
 189                         /**  Contains the current scheduler tick count, for use with the delay functions. If the delay functions
 190                          *   are used in the user code, this should be incremented each tick period so that the delays can be
 191                          *   calculated.
 192                          */
 193                         extern volatile SchedulerDelayCounter_t   Scheduler_TickCounter;
 194
 195                 /* Inline Functions: */
 196                         /** Resets the delay counter value to the current tick count. This should be called to reset the period
 197                          *  for a delay in a task which is dependant on the current tick value.
 198                          *
 199                          *  \param[out] DelayCounter  Counter which is storing the starting tick count for a given delay.
 200                          */
 201                         static inline void Scheduler_ResetDelay(SchedulerDelayCounter_t* const DelayCounter)
 202                                                                 ATTR_NON_NULL_PTR_ARG(1) ATTR_ALWAYS_INLINE;
 203                         static inline void Scheduler_ResetDelay(SchedulerDelayCounter_t* const DelayCounter)
 204                         {
 205                                 ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
 206                                 {
 207                                         *DelayCounter = Scheduler_TickCounter;
 208                                 }
 209                         }
 210
 211                 /* Function Prototypes: */
 212                         /** Determines if the given tick delay has elapsed, based on the given .
 213                          *
 214                          *  \param[in] Delay         The delay to test for, measured in ticks
 215                          *  \param[in] DelayCounter  The counter which is storing the starting tick value for the delay
 216                          *
 217                          *  \return Boolean true if the delay has elapsed, false otherwise
 218                          *
 219                          *  Usage Example:
 220                          *  \code
 221                          *      static SchedulerDelayCounter_t DelayCounter = 10000; // Force immediate run on start-up
 222                          *
 223                          *      // Task runs every 10000 ticks, 10 seconds for this demo
 224                          *      if (Scheduler_HasDelayElapsed(10000, &DelayCounter))
 225                          *      {
 226                          *           // Code to execute after delay interval elapsed here
 227                          *      }
 228                          *  \endcode
 229                          */
 230                         bool Scheduler_HasDelayElapsed(const uint16_t Delay,
 231                                                        SchedulerDelayCounter_t* const DelayCounter)
 232                                                                                    ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(2);
 233
 234                         /** Sets the task mode for a given task.
 235                          *
 236                          *  \param[in] Task        Name of the task whose status is to be changed
 237                          *  \param[in] TaskStatus  New task status for the task (TASK_RUN or TASK_STOP)
 238                          */
 239                         void Scheduler_SetTaskMode(const TaskPtr_t Task, const bool TaskStatus);
 240
 241                         /** Sets the task mode for a given task group ID, allowing for an entire group of tasks to have their
 242                          *  statuses changed at once.
 243                          *
 244                          *  \param[in] GroupID     Value of the task group ID whose status is to be changed
 245                          *  \param[in] TaskStatus  New task status for tasks in the specified group (TASK_RUN or TASK_STOP)
 246                          */
 247                         void Scheduler_SetGroupTaskMode(const uint8_t GroupID, const bool TaskStatus);
 248
 249         /* Private Interface - For use in library only: */
 250         #if !defined(__DOXYGEN__)
 251                 /* Macros: */
 252                         #define TOTAL_TASKS                       (sizeof(Scheduler_TaskList) / sizeof(TaskEntry_t))
 253                         #define MAX_DELAYCTR_COUNT                0xFFFF
 254
 255                 /* Inline Functions: */
 256                         static inline void Scheduler_InitScheduler(const uint8_t TotalTasks) ATTR_ALWAYS_INLINE;
 257                         static inline void Scheduler_InitScheduler(const uint8_t TotalTasks)
 258                         {
 259                                 Scheduler_TotalTasks = TotalTasks;
 260                         }
 261
 262                         static inline void Scheduler_GoSchedule(const uint8_t TotalTasks) ATTR_NO_RETURN ATTR_ALWAYS_INLINE ATTR_DEPRECATED;
 263                         static inline void Scheduler_GoSchedule(const uint8_t TotalTasks)
 264                         {
 265                                 Scheduler_InitScheduler(TotalTasks);
 266
 267                                 for (;;)
 268                                 {
 269                                         TaskEntry_t* CurrTask = &Scheduler_TaskList[0];
 270
 271                                         while (CurrTask != &Scheduler_TaskList[TotalTasks])
 272                                         {
 273                                                 if (CurrTask->TaskStatus == TASK_RUN)
 274                                                   CurrTask->Task();
 275
 276                                                 CurrTask++;
 277                                         }
 278                                 }
 279                         }
 280         #endif
 281
 282         /* Disable C linkage for C++ Compilers: */
 283                 #if defined(__cplusplus)
 284                         }
 285                 #endif
 286
 287 #endif
 288
 289 /** @} */