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/******************************************************************************

*                                                                             *

* License Agreement                                                           *

*                                                                             *

* Copyright (c) 2004 Altera Corporation, San Jose, California, USA.           *

* All rights reserved.                                                        *

*                                                                             *

* Permission is hereby granted, free of charge, to any person obtaining a     *

* copy of this software and associated documentation files (the "Software"),  *

* to deal in the Software without restriction, including without limitation   *

* the rights to use, copy, modify, merge, publish, distribute, sublicense,    *

* and/or sell copies of the Software, and to permit persons to whom the       *

* Software is furnished to do so, subject to the following conditions:        *

*                                                                             *

* The above copyright notice and this permission notice shall be included in  *

* all copies or substantial portions of the Software.                         *

*                                                                             *

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  *

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,    *

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *

* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER      *

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING     *

* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER         *

* DEALINGS IN THE SOFTWARE.                                                   *

*                                                                             *

* This agreement shall be governed in all respects by the laws of the State   *

* of California and by the laws of the United States of America.              *

*                                                                             *

* Altera does not recommend, suggest or require that this reference design    *

* file be used in conjunction or combination with any other product.          *

******************************************************************************/

#include <errno.h>

#include "sys/alt_alarm.h"

#include "sys/alt_irq.h"

/*

 * alt_alarm_start is called to register an alarm with the system. The

 * "alarm" structure passed as an input argument does not need to be

 * initialised by the user. This is done within this function.

 *

 * The remaining input arguments are:

 *

 * nticks - The time to elapse until the alarm executes. This is specified in

 *          system clock ticks.

 * callback - The function to run when the indicated time has elapsed.

 * context  - An opaque value, passed to the callback function.

*

 * Care should be taken when defining the callback function since it is

 * likely to execute in interrupt context. In particular, this mean that

 * library calls like printf() should not be made, since they can result in

 * deadlock.

 *

 * The interval to be used for the next callback is the return

 * value from the callback function. A return value of zero indicates that the

 * alarm should be unregistered.

 *

 * alt_alarm_start() will fail if  the timer facility has not been enabled

 * (i.e. there is no system clock). Failure is indicated by a negative return

 * value.

 */

int alt_alarm_start (alt_alarm* alarm, alt_u32 nticks,

                     alt_u32 (*callback) (void* context),

                     void* context)

{

  alt_irq_context irq_context;

  alt_u32 current_nticks = 0;

  if (alt_ticks_per_second ())

  {

    if (alarm)

    {

      alarm->callback = callback;

      alarm->context  = context;

      irq_context = alt_irq_disable_all ();

      current_nticks = alt_nticks();

      alarm->time = nticks + current_nticks + 1;

      /*

       * If the desired alarm time causes a roll-over, set the rollover

       * flag. This will prevent the subsequent tick event from causing

       * an alarm too early.

       */

      if(alarm->time < current_nticks)

      {

        alarm->rollover = 1;

      }

      else

      {

        alarm->rollover = 0;

      }

      alt_llist_insert (&alt_alarm_list, &alarm->llist);

      alt_irq_enable_all (irq_context);

      return 0;

    }

    else

    {

      return -EINVAL;

    }

  }

  else

  {

    return -ENOTSUP;

  }

}