os_tick.c

UCOS-III

/*
***********************************************************************************************************************
*                                                      uC/OS-III
*                                                 The Real-Time Kernel
*
*                                  (c) Copyright 2009-2011; Micrium, Inc.; Weston, FL
*                           All rights reserved.  Protected by international copyright laws.
*
*                                                   TICK MANAGEMENT
*
* File    : OS_TICK.C
* By      : JJL
* Version : V3.02.00
*
* LICENSING TERMS:
* ---------------
*           uC/OS-III is provided in source form for FREE short-term evaluation, for educational use or 
*           for peaceful research.  If you plan or intend to use uC/OS-III in a commercial application/
*           product then, you need to contact Micrium to properly license uC/OS-III for its use in your 
*           application/product.   We provide ALL the source code for your convenience and to help you 
*           experience uC/OS-III.  The fact that the source is provided does NOT mean that you can use 
*           it commercially without paying a licensing fee.
*
*           Knowledge of the source code may NOT be used to develop a similar product.
*
*           Please help us continue to provide the embedded community with the finest software available.
*           Your honesty is greatly appreciated.
*
*           You can contact us at www.micrium.com, or by phone at [phone].
************************************************************************************************************************
*/

#include <os.h>

#ifdef VSC_INCLUDE_SOURCE_FILE_NAMES
const  CPU_CHAR  *os_tick__c = "$Id: $";
#endif

/*
************************************************************************************************************************
*                                                  LOCAL PROTOTYPES
************************************************************************************************************************
*/


/*
************************************************************************************************************************
*                                                      TICK TASK
*
* Description: This task is internal to uC/OS-III and is triggered by the tick interrupt.
*
* Arguments  : p_arg     is an argument passed to the task when the task is created (unused).
*
* Returns    : none
*
* Note(s)    : This function is INTERNAL to uC/OS-III and your application should not call it.
************************************************************************************************************************
*/

void  OS_TickTask (void *p_arg)
{
    OS_ERR  err;
    CPU_TS  ts;


    p_arg = p_arg;                                          /* Prevent compiler warning                               */

    while (DEF_ON) {
        (void)OSTaskSemPend((OS_TICK  )0,
                            (OS_OPT   )OS_OPT_PEND_BLOCKING,
                            (CPU_TS  *)&ts,
                            (OS_ERR  *)&err);               /* Wait for signal from tick interrupt                    */
        if (err == OS_ERR_NONE) {
            if (OSRunning == OS_STATE_OS_RUNNING) {
                OS_TickListUpdate();                        /* Update all tasks waiting for time                      */
            }
        }
    }
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                                 INITIALIZE TICK TASK
*
* Description: This function is called by OSInit() to create the tick task.
*
* Arguments  : p_err   is a pointer to a variable that will hold the value of an error code:
*
*                          OS_ERR_TICK_STK_INVALID   if the pointer to the tick task stack is a NULL pointer
*                          OS_ERR_TICK_STK_SIZE      indicates that the specified stack size
*                          OS_ERR_PRIO_INVALID       if the priority you specified in the configuration is invalid
*                                                      (There could be only one task at the Idle Task priority)
*                                                      (Maybe the priority you specified is higher than OS_CFG_PRIO_MAX-1
*                          OS_ERR_??                 other error code returned by OSTaskCreate()
*
* Returns    : none
*
* Note(s)    : This function is INTERNAL to uC/OS-III and your application should not call it.
************************************************************************************************************************
*/

void  OS_TickTaskInit (OS_ERR  *p_err)
{
#ifdef OS_SAFETY_CRITICAL
    if (p_err == (OS_ERR *)0) {
        OS_SAFETY_CRITICAL_EXCEPTION();
        return;
    }
#endif

    OSTickCtr         = (OS_TICK)0u;                        /* Clear the tick counter                                 */

    OSTickTaskTimeMax = (CPU_TS)0u;


    OS_TickListInit();                                      /* Initialize the tick list data structures               */

                                                            /* ---------------- CREATE THE TICK TASK ---------------- */
    if (OSCfg_TickTaskPrio >= (OS_CFG_PRIO_MAX - 1u)) {     /* Only one task at the 'Idle Task' priority              */
        *p_err = OS_ERR_PRIO_INVALID;
        return;
    }

    OSTaskCreate((OS_TCB     *)&OSTickTaskTCB,
                 (CPU_CHAR   *)((void *)"uC/OS-III Tick Task"),
                 (OS_TASK_PTR )OS_TickTask,
                 (void       *)0,
                 (OS_PRIO     )OSCfg_TickTaskPrio,
                 (CPU_STK    *)OSCfg_TickTaskStkBasePtr,
                 (CPU_STK_SIZE)OSCfg_TickTaskStkLimit,
                 (CPU_STK_SIZE)OSCfg_TickTaskStkSize,
                 (OS_MSG_QTY  )0u,
                 (OS_TICK     )0u,
                 (void       *)0,
                 (OS_OPT      )(OS_OPT_TASK_STK_CHK | OS_OPT_TASK_STK_CLR),
                 (OS_ERR     *)p_err);
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                               INITIALIZE THE TICK LIST
*
* Description: This function initializes the tick handling data structures of uC/OS-III.
*
* Arguments  : none
*
* Returns    : None
*
* Note(s)    : This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
************************************************************************************************************************
*/

void  OS_TickListInit (void)
{
    OS_TICK_SPOKE_IX   i;
    OS_TICK_SPOKE     *p_spoke;



    for (i = 0u; i < OSCfg_TickWheelSize; i++) {
        p_spoke                = (OS_TICK_SPOKE *)&OSCfg_TickWheel[i];
        p_spoke->FirstPtr      = (OS_TCB        *)0;
        p_spoke->NbrEntries    = (OS_OBJ_QTY     )0u;
        p_spoke->NbrEntriesMax = (OS_OBJ_QTY     )0u;
    }
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                                ADD TASK TO TICK LIST
*
* Description: This function is called to place a task in a list of task waiting for either time to expire or waiting to
*              timeout on a pend call.
*
* Arguments  : p_tcb          is a pointer to the OS_TCB of the task to add to the tick list
*              -----
*
*              time           represents either the 'match' value of OSTickCtr or a relative time from the current
*                             value of OSTickCtr as specified by the 'opt' argument..
*
*                             relative when 'opt' is set to OS_OPT_TIME_DLY
*                             relative when 'opt' is set to OS_OPT_TIME_TIMEOUT
*                             match    when 'opt' is set to OS_OPT_TIME_MATCH
*                             periodic when 'opt' is set to OS_OPT_TIME_PERIODIC
*
*              opt            is an option specifying how to calculate time.  The valid values are:
*              ---
*                                 OS_OPT_TIME_DLY
*                                 OS_OPT_TIME_TIMEOUT
*                                 OS_OPT_TIME_PERIODIC
*                                 OS_OPT_TIME_MATCH
*
*              p_err          is a pointer to a variable that will contain an error code returned by this function.
*              -----
*                                 OS_ERR_NONE           the call was successful and the time delay was scheduled.
*                                 OS_ERR_TIME_ZERO_DLY  if delay is zero or already occurred.
*
* Returns    : None
*
* Note(s)    : 1) This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
*
*              2) This function is assumed to be called with interrupts disabled.
************************************************************************************************************************
*/

void  OS_TickListInsert (OS_TCB   *p_tcb,
                         OS_TICK   time,
                         OS_OPT    opt,
                         OS_ERR   *p_err)
{
    OS_TICK            tick_delta;
    OS_TICK            tick_next;
    OS_TICK_SPOKE     *p_spoke;
    OS_TCB            *p_tcb0;
    OS_TCB            *p_tcb1;
    OS_TICK_SPOKE_IX   spoke;



    if (opt == OS_OPT_TIME_MATCH) {                              /* Task time is absolute.                            */
        tick_delta = time - OSTickCtr - 1u;
        if (tick_delta > OS_TICK_TH_RDY) {                       /* If delay already occurred, ...                    */
            p_tcb->TickCtrMatch = (OS_TICK        )0u;
            p_tcb->TickRemain   = (OS_TICK        )0u;
            p_tcb->TickSpokePtr = (OS_TICK_SPOKE *)0;
           *p_err               =  OS_ERR_TIME_ZERO_DLY;         /* ... do NOT delay.                                 */
            return;
        }
        p_tcb->TickCtrMatch = time;
        p_tcb->TickRemain   = tick_delta + 1u;

    } else if (time > (OS_TICK)0u) {
        if (opt == OS_OPT_TIME_PERIODIC) {                       /* Task time is periodic.                            */
            tick_next  = p_tcb->TickCtrPrev + time;
            tick_delta = tick_next - OSTickCtr - 1u;
            if (tick_delta < time) {                             /* If next periodic delay did NOT already occur, ... */
                p_tcb->TickCtrMatch = tick_next;                 /* ... set  next  periodic delay;                ... */
            } else {
                p_tcb->TickCtrMatch = OSTickCtr + time;          /* ... else reset periodic delay.                    */
            }
            p_tcb->TickRemain   = p_tcb->TickCtrMatch - OSTickCtr;
            p_tcb->TickCtrPrev  = p_tcb->TickCtrMatch;

        } else {                                                 /* Task time is relative to current.                 */
            p_tcb->TickCtrMatch = OSTickCtr + time;
            p_tcb->TickRemain   = time;
        }

    } else {                                                     /* Zero time delay; ...                              */
        p_tcb->TickCtrMatch = (OS_TICK        )0u;
        p_tcb->TickRemain   = (OS_TICK        )0u;