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//==========================================================================

//

//        lib/timeout.c

//

//        timeout support

//

//==========================================================================

// ####BSDALTCOPYRIGHTBEGIN####                                             

// -------------------------------------------                              

// Portions of this software may have been derived from OpenBSD             

// or other sources, and if so are covered by the appropriate copyright     

// and license included herein.                                             

// -------------------------------------------                              

// ####BSDALTCOPYRIGHTEND####                                               

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):     gthomas, hmt

// Contributors:  gthomas, hmt

// Date:          1999-02-05

// Description:   Simple timeout functions

//####DESCRIPTIONEND####

#include <sys/param.h>

#include <pkgconf/net.h>

#include <cyg/kernel/kapi.h>

#include <cyg/infra/cyg_ass.h>

// Timeout support

void alarm_timeout_init(void);

#ifndef NTIMEOUTS

#define NTIMEOUTS 8

#endif

typedef struct {

    cyg_int32     delta;  // Number of "ticks" in the future for this timeout

    timeout_fun  *fun;    // Function to execute when it expires

    void         *arg;    // Argument to pass when it does

} timeout_entry;

static timeout_entry timeouts[NTIMEOUTS];

static cyg_handle_t timeout_alarm_handle;

static cyg_alarm timeout_alarm;

static cyg_int32 last_delta;

static cyg_tick_count_t last_set_time;

#define STACK_SIZE CYGNUM_HAL_STACK_SIZE_TYPICAL

static char alarm_stack[STACK_SIZE];

static cyg_thread alarm_thread_data;

static cyg_handle_t alarm_thread_handle;

static cyg_flag_t alarm_flag;

// ------------------------------------------------------------------------

// This routine exists so that this module can synchronize:

extern cyg_uint32 cyg_splinternal(void);

// ------------------------------------------------------------------------

// CALLBACK FUNCTION

// Called from the thread, this runs the alarm callbacks.

// Locking is already in place when this is called.

static void

do_timeout(void)

{

    int i;

    cyg_int32 min_delta;

    timeout_entry *e;

    CYG_ASSERT( 0 < last_delta, "last_delta underflow" );

    min_delta = last_delta; // local copy

    last_delta = -1; // flag recursive call underway

    for (e = timeouts, i = 0;  i < NTIMEOUTS;  i++, e++) {

        if (e->delta) {

            CYG_ASSERT( e->delta >= min_delta, "e->delta underflow" );

            e->delta -= min_delta;

            if (e->delta <= 0) { // Defensive

                // Time for this item to 'fire'

                timeout_fun *fun = e->fun;

                void *arg = e->arg;

                // Call it *after* cleansing the record

                e->fun = 0;

                e->delta = 0;

                (*fun)(arg);

            }

        }

    }

    // Now scan for a new timeout *after* running all the callbacks

    // (because they can add timeouts themselves)

    min_delta = 0x7FFFFFFF;  // Maxint

    for (e = timeouts, i = 0;  i < NTIMEOUTS;  i++, e++)

        if (e->delta)

            if (e->delta < min_delta)

                min_delta = e->delta;

    CYG_ASSERT( 0 < min_delta, "min_delta underflow" );

    if (min_delta != 0x7FFFFFFF) {

        // Still something to do, schedule it

        last_set_time = cyg_current_time();

        cyg_alarm_initialize(timeout_alarm_handle, last_set_time+min_delta, 0);

        last_delta = min_delta;

    } else {

        last_delta = 0; // flag no activity

    }

}

// ------------------------------------------------------------------------

// ALARM EVENT FUNCTION

// This is the DSR for the alarm firing:

static void

do_alarm(cyg_handle_t alarm, cyg_addrword_t data)

{

    cyg_flag_setbits( &alarm_flag, 1 );

}

void ecos_synch_eth_drv_dsr(void)

{

    cyg_flag_setbits( &alarm_flag, 2 );

}

// ------------------------------------------------------------------------

// HANDLER THREAD ENTRY ROUTINE

// This waits on the DSR to tell it to run:

static void

alarm_thread(cyg_addrword_t param)

{

    // This is from the logical ethernet dev; it calls those delivery

    // functions who need attention.

    extern void eth_drv_run_deliveries( void );

    // This is from the logical ethernet dev; it tickles somehow

    // all ethernet devices in case one is wedged.

    extern void eth_drv_tickle_devices( void );

    while ( 1 ) {

        int spl;

        int x;

#ifdef CYGPKG_NET_FAST_THREAD_TICKLE_DEVS

        cyg_tick_count_t later = cyg_current_time();

        later += CYGNUM_NET_FAST_THREAD_TICKLE_DEVS_DELAY;

        x = cyg_flag_timed_wait(

            &alarm_flag,

            -1,

            CYG_FLAG_WAITMODE_OR | CYG_FLAG_WAITMODE_CLR,

            later );

#else

        x = cyg_flag_wait(

            &alarm_flag,

            -1,

            CYG_FLAG_WAITMODE_OR | CYG_FLAG_WAITMODE_CLR );

        CYG_ASSERT( 3 & x, "Lost my bits" );

#endif // CYGPKG_NET_FAST_THREAD_TICKLE_DEVS

        CYG_ASSERT( !((~3) & x), "Extra bits" );

        spl = cyg_splinternal();

        CYG_ASSERT( 0 == spl, "spl nonzero" );

        if ( 2 & x )

            eth_drv_run_deliveries();

#ifdef CYGPKG_NET_FAST_THREAD_TICKLE_DEVS

        // This is in the else clause for "do we deliver" because the

        // network stack might have continuous timing events anyway - so

        // the timeout would not occur, x would be 1 every time.

        else // Tickle the devices...

            eth_drv_tickle_devices();

#endif // CYGPKG_NET_FAST_THREAD_TICKLE_DEVS

        if ( 1 & x )

            do_timeout();

        cyg_splx(spl);

    }

}

// ------------------------------------------------------------------------

// INITIALIZATION FUNCTION

void

cyg_alarm_timeout_init( void )

{

    // Init the alarm object, attached to the real time clock

    cyg_handle_t h;

    cyg_clock_to_counter(cyg_real_time_clock(), &h);

    cyg_alarm_create(h, do_alarm, 0, &timeout_alarm_handle, &timeout_alarm);

    // Init the flag of waking up

    cyg_flag_init( &alarm_flag );

    // Create alarm background thread to run the callbacks

    cyg_thread_create(

        CYGPKG_NET_FAST_THREAD_PRIORITY, // Priority

        alarm_thread,                   // entry

        0,                              // entry parameter

        "Network alarm support",        // Name

        &alarm_stack[0],                // Stack

        STACK_SIZE,                     // Size

        &alarm_thread_handle,           // Handle

        &alarm_thread_data              // Thread data structure

        );

    cyg_thread_resume(alarm_thread_handle);    // Start it

}

// ------------------------------------------------------------------------

// EXPORTED API: SET A TIMEOUT

// This can be called from anywhere, including recursively from the timeout

// functions themselves.

cyg_uint32

timeout(timeout_fun *fun, void *arg, cyg_int32 delta)

{

    int i;

    timeout_entry *e;

    cyg_uint32 stamp;

    // this needs to be atomic - recursive calls from the alarm

    // handler thread itself are allowed:

    int spl = cyg_splinternal();

    CYG_ASSERT( 0 < delta, "delta is right now, or even sooner!" );

    // Renormalize delta wrt the existing set alarm, if there is one

    if ( last_delta > 0 )

        delta += (cyg_int32)(cyg_current_time() - last_set_time);

    // So recorded_delta is set to either:

    // alarm is active:   delta + NOW - THEN

    // alarm is inactive: delta

    stamp = 0;  // Assume no slots available

    for (e = timeouts, i = 0;  i < NTIMEOUTS;  i++, e++) {

        if ((e->delta == 0) && (e->fun == 0)) {

            // Free entry

            e->delta = delta;

            e->fun = fun;

            e->arg = arg;

            stamp = (cyg_uint32)e;

            break;

        }

    }

    if ( stamp &&                 // we did add a record AND

         (0 == last_delta ||      // alarm was inactive  OR

          delta < last_delta) ) { // alarm was active but later than we need

        // (if last_delta is -1, this call is recursive from the handler so

        //  also do nothing in that case)

        // Here, we know the new item added is sooner than that which was

        // most recently set, if any, so we can just go and set it up.

        if ( 0 == last_delta )

            last_set_time = cyg_current_time();

        // So we use, to set the alarm either:

        // alarm is active:   (delta + NOW - THEN) + THEN

        // alarm is inactive:  delta + NOW

        // and in either case it is true that

        //  (recorded_delta + last_set_time) == (delta + NOW)

        cyg_alarm_initialize(timeout_alarm_handle, last_set_time+delta, 0);

        last_delta = delta;

    }

    // Otherwise, the alarm is active, AND it is set to fire sooner than we

    // require, so when it does, that will sort out calling the item we

    // just added.  Or we didn't actually add a record, so nothing has

    // changed.

#ifdef CYGPKG_INFRA_DEBUG

    // Do some more checking akin to that in the alarm handler:

    if ( last_delta != -1 ) { // not a recursive call

        cyg_tick_count_t now = cyg_current_time();

        CYG_ASSERT( last_delta >= 0, "Bad last delta" );

        delta = 0x7fffffff;

        for (e = timeouts, i = 0;  i < NTIMEOUTS;  i++, e++) {

            if (e->delta) {

                CYG_ASSERT( e->delta >= last_delta, "e->delta underflow" );

                CYG_ASSERT( last_set_time + e->delta + 1000 > now,

                            "Recorded alarm not in the future!" );

                if ( e->delta < delta )

                    delta = e->delta;

            } else {

                CYG_ASSERT( 0 == e->fun, "Function recorded for 0 delta" );

            }

        }

        CYG_ASSERT( delta == last_delta, "We didn't pick the smallest delta!" );

    }

#endif

    cyg_splx(spl);

    return stamp;

}

// ------------------------------------------------------------------------

// EXPORTED API: CANCEL A TIMEOUT

// This can be called from anywhere, including recursively from the timeout

// functions themselves.

void

untimeout(timeout_fun *fun, void * arg)

{

    int i;

    timeout_entry *e;

    int spl = cyg_splinternal();

    for (e = timeouts, i = 0; i < NTIMEOUTS; i++, e++) {

        if (e->delta && (e->fun == fun) && (e->arg == arg)) {

            e->delta = 0;

            e->fun = 0;

            break;

        }

    }

    cyg_splx(spl);

}

// ------------------------------------------------------------------------

// EOF timeout.c