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

//

//      watchdog/sa11x0.cxx

//

//      Watchdog implementation for StrongARM SA11x0s

//

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

//####ECOSGPLCOPYRIGHTBEGIN####

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

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

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

//

// Author(s):    hmt, jskov (based on the MN10300 watchdog code by nickg)

// Contributors: jskov, nickg

// Date:         2001-02-27

// Purpose:      Watchdog class implementation

// Description:  Contains an implementation of the Watchdog class for use

//               with the SA11X0 hardware watchdog timer.

//

//####DESCRIPTIONEND####

//

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

#include <pkgconf/system.h>             // system configuration file

#include <pkgconf/watchdog.h>           // configuration for this package

#include <pkgconf/kernel.h>             // kernel config

#include <cyg/infra/cyg_trac.h>         // tracing macros

#include <cyg/kernel/instrmnt.h>        // instrumentation

#include <cyg/hal/hal_io.h>             // IO register access

#include <cyg/hal/hal_intr.h>           // Interrupts

#include <cyg/hal/hal_sa11x0.h>         // IO registers per se

#include <cyg/io/watchdog.hxx>          // watchdog API

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

// SA11x0 watchdog works by enabling the watchdog (duh!) which means that

// when OS Timer Match Register #3 "OSMR3" compares equal to the 3.6864MHz

// clock in OSCR, then the system resets.

//

// To stay ahead of this, we must repeatedly set OSMR3 to OSCR + K where K

// is the watchdog timeout.  This REQUIRES that the OSCR be freerunning.

//

// OSCR runs at 3.6864MHz, so one second is 3686400 ticks.

// 

// The match register is 32 bits, and wraps as an int32 does (the

// comparison is exact, so you don't need to take special care.)  So we can

// literally do the addition in the obvious way.

#define WATCHDOG_TIMER_TICKS            3686400

#define WATCHDOG_RESOLUTION             (1000000000)

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

// Constructor

void

Cyg_Watchdog::init_hw(void)

{

    CYG_REPORT_FUNCTION();

    // HW doesn't need init

    resolution          = WATCHDOG_RESOLUTION;

    CYG_REPORT_RETURN();

}

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

// Start the watchdog running.

void

Cyg_Watchdog::start(void)

{

    int old;

    CYG_REPORT_FUNCTION();

    HAL_DISABLE_INTERRUPTS( old );

    // Init the watchdog timer.

    *SA11X0_OSMR3 = *SA11X0_OSCR + WATCHDOG_TIMER_TICKS;

    *SA11X0_OSSR = SA11X0_OSSR_TIMER3; // Ack any pending intr

    *SA11X0_OIER |= SA11X0_OIER_TIMER3; // Enable interrupt is necessary

    CYG_ASSERT( *SA11X0_OSCR < *SA11X0_OSMR3 ||

                *SA11X0_OSMR3 <= WATCHDOG_TIMER_TICKS, "Watchdog wierdness" );

    // Enable the watchdog.

    *SA11X0_OWER = SA11X0_OWER_ENABLE;

    HAL_RESTORE_INTERRUPTS( old );

    CYG_REPORT_RETURN();

}

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

// Reset watchdog timer. This needs to be called regularly to prevent

// the watchdog firing.

void

Cyg_Watchdog::reset()

{

    CYG_REPORT_FUNCTION();

    *SA11X0_OSMR3 = *SA11X0_OSCR + WATCHDOG_TIMER_TICKS;

    CYG_ASSERT( *SA11X0_OSCR < *SA11X0_OSMR3 ||

                *SA11X0_OSMR3 <= WATCHDOG_TIMER_TICKS, "Watchdog wierdness" );

    CYG_REPORT_RETURN();

}

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

// EOF watchdog_sa11x0.cxx