text: /******************************************************************************
   *
   *  Copyright (C) 2014 Google, Inc.
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at:
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   ******************************************************************************/
  
  #ifndef _ALARM_H_
  #define _ALARM_H_
  
  #include <stdint.h>
  #include <freertos/FreeRTOS.h>
  #include <freertos/timers.h>
  
  typedef uint32_t period_ms_t;
  typedef void (*osi_alarm_callback_t)(void *data);
  
  #define ALARM_CBS_NUM   20
  #define ALARM_ID_BASE   1000
  typedef struct alarm_t {
      /* timer id point to here */
      TimerHandle_t alarm_hdl;
      osi_alarm_callback_t cb;
      void *cb_data;
  } osi_alarm_t;
  
  int osi_alarm_create_mux(void);
  int osi_alarm_delete_mux(void);
  void osi_alarm_init(void);
  void osi_alarm_deinit(void);
  
  // Creates a new alarm object. The returned object must be freed by calling
  // |alarm_free|. Returns NULL on failure.
  osi_alarm_t *osi_alarm_new(char *alarm_name, osi_alarm_callback_t callback, void *data, period_ms_t timer_expire);
  
  // Frees an alarm object created by |alarm_new|. |alarm| may be NULL. If the
  // alarm is pending, it will be cancelled. It is not safe to call |alarm_free|
  // from inside the callback of |alarm|.
  int osi_alarm_free(osi_alarm_t *alarm);
  
  // Sets an alarm to fire |cb| after the given |deadline|. Note that |deadline| is the
  // number of milliseconds relative to the current time. |data| is a context variable
  // for the callback and may be NULL. |cb| will be called back in the context of an
  // unspecified thread (i.e. it will not be called back in the same thread as the caller).
  // |alarm| and |cb| may not be NULL.
  int osi_alarm_set(osi_alarm_t *alarm, period_ms_t timeout);
  
  // This function cancels the |alarm| if it was previously set. When this call
  // returns, the caller has a guarantee that the callback is not in progress and
  // will not be called if it hasn't already been called. This function is idempotent.
  // |alarm| may not be NULL.
  int osi_alarm_cancel(osi_alarm_t *alarm);
  
  period_ms_t osi_alarm_now(void);
  
  // Figure out how much time until next expiration.
  // Returns 0 if not armed. |alarm| may not be NULL.
  // TODO: Remove this function once PM timers can be re-factored
  period_ms_t osi_alarm_get_remaining_ms(const osi_alarm_t *alarm);
  
  // Alarm-related state cleanup
  //void alarm_cleanup(void);
  
  // Compute time difference (t1-t2) considering tick counter wrap
  // t1 and t2 should be no greater than the time of MAX ticks
  period_ms_t osi_alarm_time_diff(period_ms_t t1, period_ms_t t2);
  
  #endif /*_ALARM_H_*/
  