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/* Project:     OSLib

 * Description: The OS Construction Kit

 * Date:                1.6.2000

 * Idea by:             Luca Abeni & Gerardo Lamastra

 *

 * OSLib is an SO project aimed at developing a common, easy-to-use

 * low-level infrastructure for developing OS kernels and Embedded

 * Applications; it partially derives from the HARTIK project but it

 * currently is independently developed.

 *

 * OSLib is distributed under GPL License, and some of its code has

 * been derived from the Linux kernel source; also some important

 * ideas come from studying the DJGPP go32 extender.

 *

 * We acknowledge the Linux Community, Free Software Foundation,

 * D.J. Delorie and all the other developers who believe in the

 * freedom of software and ideas.

 *

 * For legalese, check out the included GPL license.

 */

/*      Time Event routines     */

#include <ll/i386/stdlib.h>

#include <ll/i386/mem.h>

#include <ll/i386/error.h>

#include <ll/i386/hw-arch.h>

#include <ll/i386/pic.h>

#include <ll/i386/pit.h>

#include <ll/sys/ll/ll-data.h>

#include <ll/sys/ll/ll-instr.h>

#include <ll/sys/ll/time.h>

#include <ll/sys/ll/event.h>

FILE(Event);

extern LL_ARCH ll_arch;

BYTE frc;

/* Timer 0 usec base tick */

DWORD ticksize;

/* Timer 0 loaded time constant (= ticksize * 1.197) */

WORD pit_time_const;

DWORD timermode;

static DWORD nts;               /* System tick in nanoSeconds... */

struct timespec actTime;        /* Time (in nanosecs)... */

extern int activeInt;

WORD lastTime;

struct pitspec globalCounter;

struct event eventlist[MAX_EVENT];

struct event *freeevents;

struct event *firstevent;

extern void *last_handler;

extern void (*evt_prol) (void);

extern void (*evt_epil) (void);

void event_setlasthandler(void *p)

{

    last_handler = p;

}                                                                              

void event_setprologue(void *p)

{

    evt_prol = p;

}

void event_setepilogue(void *p)

{

    evt_epil = p;

}

/* Switched to timespec */

int periodic_event_post(struct timespec time, void (*handler) (void *p),

                        void *par)

{

    struct event *p;

    struct event *p1, *t;

    if (!freeevents) {

        return -1;

    }

    /* Extract from the ``free events'' queue */

    p = freeevents;

    freeevents = p->next;

    /* Fill the event fields */

    p->handler = handler;

    TIMESPEC_ASSIGN(&(p->time), &time);

    p->par = par;

    /* ...And insert it in the event queue!!! */

    t = NULL;

    /* walk through list, finding spot, adjusting ticks parameter */

    for (p1 = firstevent; p1; p1 = t->next) {

/*

                SUBTIMESPEC(&time, &(p1->time), &tmp);

                if ((tmp.tv_sec > 0) && (tmp.tv_nsec > 0)) {

*/

        if (TIMESPEC_A_GT_B(&time, &p1->time))

            t = p1;

        else

            break;

    }

    /* adjust next entry */

    if (t) {

        t->next = p;

    } else {

        firstevent = p;

    }

    p->next = p1;

    return p->index;

}

int periodic_event_delete(int index)

{

    struct event *p1, *t;

    t = NULL;

    /* walk through list, finding spot, adjusting ticks parameter */

    for (p1 = firstevent; (p1) && (index != p1->index); p1 = t->next) {

        t = p1;

    }

    if (p1 == NULL) {

        return -1;

    }

    if (t == NULL) {

        firstevent = p1->next;

    } else {

        t->next = p1->next;

    }

    p1->next = freeevents;

    freeevents = p1;

    return 1;

}

void periodic_wake_up(void)

{                               /* CHANGE the NAME, please... */

    struct event *p, *pp;

    WORD tmp;

    tmp = pit_read(frc);

    ADDPITSPEC((WORD) (lastTime - tmp), &globalCounter);

    lastTime = tmp;

    activeInt++;

    if (activeInt == 1 && evt_prol != NULL) {

        evt_prol();

    }

    ADDNANO2TIMESPEC(nts, &actTime);

    for (p = firstevent; p != NULL; p = pp) {

/*

                SUBTIMESPEC(&(p->time), &actTime, &tmp);

                if ((tmp.tv_sec > 0) && (tmp.tv_nsec > 0)) {

                        break;

                } */

        if ((p->time.tv_sec > actTime.tv_sec) ||

            ((p->time.tv_sec == actTime.tv_sec)

             && (p->time.tv_nsec > actTime.tv_nsec))) {

            break;

        }

        pp = p->next;

        p->next = freeevents;

        freeevents = p;

        firstevent = pp;

        p->handler(p->par);

    }

    if (activeInt == 1 && evt_epil != NULL) {

        evt_epil();

    }

    activeInt--;

}

void event_init(struct ll_initparms *l)

{

    extern void ll_timer(void);

    int i;

    BYTE mask;

    TIME t;

    IDT_place(0x40,ll_timer);

    if (l->mode != LL_PERIODIC) {

        error("Trying one-shot!!!");

        t = 0;

        /* Mode: Binary/Mode 4/16 bit Time_const/Counter 0 */

        pit_init(0, TMR_MD4, 0xFFFF);   /* Timer 0, Mode 4, constant 0xFFFF */

    } else {

        t = l->tick;

        /* Translate the tick value in usec into a suitable time constant   */

        /* for 8254 timer chip; the chip is driven with a 1.19718 MHz       */

        /* frequency; then the effective frequency is given by the base     */

        /* frequency divided for the time constant; the tick is the inverse */

        /* of this effective frequency (in usec!)                           */

        /* Time-Constant = f_base (MHz) * tick (usec)                       */

        /* If T-C == 0 -> T-C = 65536 (Max available)                       */

        ticksize = t;

        t = t * 1197;

        t = t / 1000;

        /* Only for security! This should cause timer overrun */

        /* While 0 would set maximum period on timer          */

        if (t == 0)

            t = 1;

        pit_time_const = (WORD) (t & 0xFFFF);

        /* Mode: Binary/Mode 2/16 bit Time_const/Counter 0 */

        pit_init(0, TMR_MD2, t);        /* Timer 0, Mode 2, Time constant t */

    }

    timermode = l->mode;

    if (ll_arch.x86.cpu > 4) {

        /* Timer1: mode 0, time const 0... */

        pit_init(1, TMR_MD0, 0);

        frc = 1;

    } else {

        frc = 2;

        pit_init(2, TMR_MD0, 0);

         outp(0x61, 3);

    }

    mask = ll_in(0x21);

    mask &= 0xFE;               /* 0xFE = ~0x01 */

    ll_out(0x21, mask);

    /* Init the event list... */

    for (i = 0; i < MAX_EVENT; i++) {

        if (i < MAX_EVENT - 1) {

            eventlist[i].next = &(eventlist[i + 1]);

        }

        eventlist[i].index = i;

    }

    eventlist[MAX_EVENT - 1].next = NULL;

    freeevents = &(eventlist[0]);

    evt_prol = NULL;

    evt_epil = NULL;

    /* Initialization of the time variables for periodic mode */

    nts = ticksize * 1000;

    NULL_TIMESPEC(&actTime);

    /* Initialization of the general time variables */

    NULLPITSPEC(&globalCounter);

    lastTime = 0;

    if (timermode == LL_PERIODIC) {

        event_post = periodic_event_post;

        event_delete = periodic_event_delete;

    } else {

        event_post = oneshot_event_post;

        event_delete = oneshot_event_delete;

    }

    /* Last but not least... */

    irq_unmask(0);

}