/*************************************************************************\
* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
*     National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
*     Operator of Los Alamos National Laboratory.
* EPICS BASE is distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution. 
\*************************************************************************/
/* osi/os/vxWorks/epicsThread.c */

/* Author:  Marty Kraimer Date:    25AUG99 */

/* This is needed for vxWorks 6.8 to prevent an obnoxious compiler warning */
#define _VSB_CONFIG_FILE <../lib/h/config/vsbConfig.h>

#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdio.h>

#include <vxWorks.h>
#include <taskLib.h>
#include <taskVarLib.h>
#include <sysLib.h>

#include "errlog.h"
#include "ellLib.h"
#include "epicsThread.h"
#include "cantProceed.h"
#include "epicsAssert.h"
#include "vxLib.h"
#include "epicsExit.h"

#if CPU_FAMILY == MC680X0
#define ARCH_STACK_FACTOR 1
#elif CPU_FAMILY == SPARC
#define ARCH_STACK_FACTOR 2
#else
#define ARCH_STACK_FACTOR 2
#endif
static const unsigned stackSizeTable[epicsThreadStackBig+1] = 
   {4000*ARCH_STACK_FACTOR, 6000*ARCH_STACK_FACTOR, 11000*ARCH_STACK_FACTOR};

/*The following forces atReboot to be loaded*/
extern int atRebootExtern;
static struct pext {
    int *pExtern;
    struct pext *pext;
} pext = {&atRebootExtern, &pext};

/* definitions for implementation of epicsThreadPrivate */
static void **papTSD = 0;
static int nepicsThreadPrivate = 0;

static SEM_ID epicsThreadOnceMutex = 0;

/* Just map osi 0 to 99 into vx 100 to 199 */
/* remember that for vxWorks lower number means higher priority */
/* vx = 100 + (99 -osi)  = 199 - osi*/
/* osi =  199 - vx */

static unsigned int getOsiPriorityValue(int ossPriority)
{   
    if ( ossPriority < 100 ) {
        return epicsThreadPriorityMax;
    }
    else if ( ossPriority > 199 ) {
        return epicsThreadPriorityMin;
    }
    else {
        return ( 199u - (unsigned int) ossPriority );
    }
}

static int getOssPriorityValue(unsigned int osiPriority)
{
    if ( osiPriority > 99 ) {
        return 100;
    }
    else {
        return ( 199 - (signed int) osiPriority );
    }
}

static void epicsThreadInit(void)
{
    static int lock = 0;

    while(!vxTas(&lock)) taskDelay(1);
    if(epicsThreadOnceMutex==0) {
        epicsThreadOnceMutex = semMCreate(
                SEM_DELETE_SAFE|SEM_INVERSION_SAFE|SEM_Q_PRIORITY);
        assert(epicsThreadOnceMutex);
    }
    lock = 0;
}

unsigned int epicsThreadGetStackSize (epicsThreadStackSizeClass stackSizeClass) 
{

    if (stackSizeClass<epicsThreadStackSmall) {
        errlogPrintf("epicsThreadGetStackSize illegal argument (too small)");
        return stackSizeTable[epicsThreadStackBig];
    }

    if (stackSizeClass>epicsThreadStackBig) {
        errlogPrintf("epicsThreadGetStackSize illegal argument (too large)");
        return stackSizeTable[epicsThreadStackBig];
    }

    return stackSizeTable[stackSizeClass];
}

struct epicsThreadOSD {};
    /* Strictly speaking this should be a WIND_TCB, but we only need it to
     * be able to create an epicsThreadId that is guaranteed never to be
     * the same as any current TID, and since TIDs are pointers this works.
     */

void epicsThreadOnce(epicsThreadOnceId *id, void (*func)(void *), void *arg)
{
    static struct epicsThreadOSD threadOnceComplete;
    #define EPICS_THREAD_ONCE_DONE &threadOnceComplete
    int result;

    epicsThreadInit();
    result = semTake(epicsThreadOnceMutex, WAIT_FOREVER);
    assert(result == OK);
    if (*id != EPICS_THREAD_ONCE_DONE) {
        if (*id == EPICS_THREAD_ONCE_INIT) { /* first call */
            *id = epicsThreadGetIdSelf();    /* mark active */
            semGive(epicsThreadOnceMutex);
            func(arg);
            result = semTake(epicsThreadOnceMutex, WAIT_FOREVER);
            assert(result == OK);
            *id = EPICS_THREAD_ONCE_DONE;    /* mark done */
        } else if (*id == epicsThreadGetIdSelf()) {
            semGive(epicsThreadOnceMutex);
            cantProceed("Recursive epicsThreadOnce() initialization\n");
        } else
            while (*id != EPICS_THREAD_ONCE_DONE) {
                /* Another thread is in the above func(arg) call. */
                semGive(epicsThreadOnceMutex);
                epicsThreadSleep(epicsThreadSleepQuantum());
                result = semTake(epicsThreadOnceMutex, WAIT_FOREVER);
                assert(result == OK);
            }
    }
    semGive(epicsThreadOnceMutex);
}

static void createFunction(EPICSTHREADFUNC func, void *parm)
{
    int tid = taskIdSelf();

    taskVarAdd(tid,(int *)(char *)&papTSD);
    /*Make sure that papTSD is still 0 after that call to taskVarAdd*/
    papTSD = 0;
    (*func)(parm);
    epicsExitCallAtThreadExits ();
    free(papTSD);
    taskVarDelete(tid,(int *)(char *)&papTSD);
}

#ifdef ALTIVEC
  #define TASK_FLAGS (VX_FP_TASK | VX_ALTIVEC_TASK)
#else
  #define TASK_FLAGS (VX_FP_TASK)
#endif
epicsThreadId epicsThreadCreate(const char *name,
    unsigned int priority, unsigned int stackSize,
    EPICSTHREADFUNC funptr,void *parm)
{
    int tid;
    if(epicsThreadOnceMutex==0) epicsThreadInit();
    if(stackSize<100) {
        errlogPrintf("epicsThreadCreate %s illegal stackSize %d\n",name,stackSize);
        return(0);
    }
    tid = taskSpawn((char *)name,getOssPriorityValue(priority),
        TASK_FLAGS, stackSize,
        (FUNCPTR)createFunction,(int)funptr,(int)parm,
        0,0,0,0,0,0,0,0);
    if(tid==ERROR) {
        errlogPrintf("epicsThreadCreate %s failure %s\n",
            name,strerror(errno));
        return(0);
    }
    return((epicsThreadId)tid);
}

void epicsThreadSuspendSelf()
{
    STATUS status;

    status = taskSuspend(taskIdSelf());
    if(status) errlogPrintf("epicsThreadSuspendSelf failed\n");
}

void epicsThreadResume(epicsThreadId id)
{
    int tid = (int)id;
    STATUS status;

    status = taskResume(tid);
    if(status) errlogPrintf("epicsThreadResume failed\n");
}

void epicsThreadExitMain(void)
{
    errlogPrintf("epicsThreadExitMain was called for vxWorks. Why?\n");
}

unsigned int epicsThreadGetPriority(epicsThreadId id)
{
    int tid = (int)id;
    STATUS status;
    int priority = 0;

    status = taskPriorityGet(tid,&priority);
    if(status) errlogPrintf("epicsThreadGetPriority failed\n");
    return(getOsiPriorityValue(priority));
}

unsigned int epicsThreadGetPrioritySelf(void)
{
    return(epicsThreadGetPriority(epicsThreadGetIdSelf()));
}

void epicsThreadSetPriority(epicsThreadId id,unsigned int osip)
{
    int tid = (int)id;
    STATUS status;
    int priority = 0;

    priority = getOssPriorityValue(osip);
    status = taskPrioritySet(tid,priority);
    if(status) errlogPrintf("epicsThreadSetPriority failed\n");
}

epicsThreadBooleanStatus epicsThreadHighestPriorityLevelBelow(
    unsigned int priority, unsigned *pPriorityJustBelow)
{
    unsigned newPriority = priority - 1;
    if (newPriority <= 99) {
        *pPriorityJustBelow = newPriority;
        return epicsThreadBooleanStatusSuccess;
    }
    return epicsThreadBooleanStatusFail;
}

epicsThreadBooleanStatus epicsThreadLowestPriorityLevelAbove(
    unsigned int priority, unsigned *pPriorityJustAbove)
{
    unsigned newPriority = priority + 1;

    newPriority = priority + 1;
    if (newPriority <= 99) {
        *pPriorityJustAbove = newPriority;
        return epicsThreadBooleanStatusSuccess;
    }
    return epicsThreadBooleanStatusFail;
}

int epicsThreadIsEqual(epicsThreadId id1, epicsThreadId id2)
{
    return((id1==id2) ? 1 : 0);
}

int epicsThreadIsSuspended(epicsThreadId id)
{
    int tid = (int)id;
    return((int)taskIsSuspended(tid));
}

void epicsThreadSleep(double seconds)
{
    STATUS status;
    int ticks;

    if(seconds<=0.0) {
        ticks = 0;
    } else {
        ticks = seconds*sysClkRateGet() + 0.5;
        if(ticks<=0) ticks = 1;
    }
    status = taskDelay(ticks);
    if(status) errlogPrintf("epicsThreadSleep\n");
}

epicsThreadId epicsThreadGetIdSelf(void)
{
    return((epicsThreadId)taskIdSelf());
}

epicsThreadId epicsThreadGetId(const char *name)
{
    int tid = taskNameToId((char *)name);
    return((epicsThreadId)(tid==ERROR?0:tid));
}

const char *epicsThreadGetNameSelf(void)
{
    return taskName(taskIdSelf());
}

void epicsThreadGetName (epicsThreadId id, char *name, size_t size)
{
    int tid = (int)id;
    strncpy(name,taskName(tid),size-1);
    name[size-1] = '\0';
}

void epicsThreadShowAll(unsigned int level)
{
    taskShow(0,2);
}

void epicsThreadShow(epicsThreadId id, unsigned int level)
{
    int tid = (int)id;

    if (level > 1) level = 1;
    if (tid)
        taskShow(tid, level);
}

/* The following algorithm was thought of by Andrew Johnson APS/ASD .
 * The basic idea is to use a single vxWorks task variable.
 * The task variable is papTSD, which is an array of pointers to the TSD
 * The array size is equal to the number of epicsThreadPrivateIds created + 1
 * when epicsThreadPrivateSet is called.
 * Until the first call to epicsThreadPrivateCreate by a application papTSD=0
 * After first call papTSD[0] is value of nepicsThreadPrivate when 
 * epicsThreadPrivateSet was last called by the thread. This is also
 * the value of epicsThreadPrivateId.
 * The algorithm allows for epicsThreadPrivateCreate being called after
 * the first call to epicsThreadPrivateSet.
 */
epicsThreadPrivateId epicsThreadPrivateCreate()
{
    static int lock = 0;
    epicsThreadPrivateId id;

    epicsThreadInit();
    /*lock is necessary because ++nepicsThreadPrivate may not be indivisible*/
    while(!vxTas(&lock)) taskDelay(1);
    id = (epicsThreadPrivateId)++nepicsThreadPrivate;
    lock = 0;
    return(id);
}

void epicsThreadPrivateDelete(epicsThreadPrivateId id)
{
    /*nothing to delete */
    return;
}

/*
 * No mutex is necessary here because by definition
 * thread variables are local to a single thread.
 */
void epicsThreadPrivateSet (epicsThreadPrivateId id, void *pvt)
{
    int int_id = (int)id;
    int nepicsThreadPrivateOld = 0;

    if (papTSD) nepicsThreadPrivateOld = (int)papTSD[0];

    if (!papTSD || nepicsThreadPrivateOld < int_id) {
        void **papTSDold = papTSD;
        int i;

        papTSD = callocMustSucceed(int_id + 1,sizeof(void *),
            "epicsThreadPrivateSet");
        papTSD[0] = (void *)(int_id);
        for (i = 1; i <= nepicsThreadPrivateOld; i++) {
            papTSD[i] = papTSDold[i];
        }
        free (papTSDold);
    }
    papTSD[int_id] = pvt;
}

void *epicsThreadPrivateGet(epicsThreadPrivateId id)
{
    int int_id = (int)id;

    /*
     * If epicsThreadPrivateGet() is called before epicsThreadPrivateSet()
     * for any particular thread, the value returned is always NULL.
     */
    if ( papTSD && int_id <= (int) papTSD[0] ) {
        return papTSD[int_id];
    }
    return NULL;
}

double epicsThreadSleepQuantum ()
{
    double HZ = sysClkRateGet ();
    return 1.0 / HZ;
}