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/* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
*
* The information contained herein is property of Nordic Semiconductor ASA.
* Terms and conditions of usage are described in detail in NORDIC
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
*
* Licensees are granted free, non-transferable use of the information. NO
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
* the file.
*
*/
/** @file
*
* @defgroup app_scheduler Scheduler
* @{
* @ingroup app_common
*
* @brief The scheduler is used for transferring execution from the interrupt context to the main
* context.
*
* @details See @ref seq_diagrams_sched for sequence diagrams illustrating the flow of events
* when using the Scheduler.
*
* @section app_scheduler_req Requirements:
*
* @subsection main_context_logic Logic in main context:
*
* - Define an event handler for each type of event expected.
* - Initialize the scheduler by calling the APP_SCHED_INIT() macro before entering the
* application main loop.
* - Call app_sched_execute() from the main loop each time the application wakes up because of an
* event (typically when sd_app_evt_wait() returns).
*
* @subsection int_context_logic Logic in interrupt context:
*
* - In the interrupt handler, call app_sched_event_put()
* with the appropriate data and event handler. This will insert an event into the
* scheduler's queue. The app_sched_execute() function will pull this event and call its
* handler in the main context.
*
* @if (SD_S110 && !SD_S310)
* For an example usage of the scheduler, see the implementations of
* @ref ble_sdk_app_hids_mouse and @ref ble_sdk_app_hids_keyboard.
* @endif
*
* @image html scheduler_working.jpg The high level design of the scheduler
*/
#ifndef APP_SCHEDULER_H__
#define APP_SCHEDULER_H__
#include <stdint.h>
#include "app_error.h"
#define APP_SCHED_EVENT_HEADER_SIZE 8 /**< Size of app_scheduler.event_header_t (only for use inside APP_SCHED_BUF_SIZE()). */
/**@brief Compute number of bytes required to hold the scheduler buffer.
*
* @param[in] EVENT_SIZE Maximum size of events to be passed through the scheduler.
* @param[in] QUEUE_SIZE Number of entries in scheduler queue (i.e. the maximum number of events
* that can be scheduled for execution).
*
* @return Required scheduler buffer size (in bytes).
*/
#define APP_SCHED_BUF_SIZE(EVENT_SIZE, QUEUE_SIZE) \
(((EVENT_SIZE) + APP_SCHED_EVENT_HEADER_SIZE) * ((QUEUE_SIZE) + 1))
/**@brief Scheduler event handler type. */
typedef void (*app_sched_event_handler_t)(void * p_event_data, uint16_t event_size);
/**@brief Macro for initializing the event scheduler.
*
* @details It will also handle dimensioning and allocation of the memory buffer required by the
* scheduler, making sure the buffer is correctly aligned.
*
* @param[in] EVENT_SIZE Maximum size of events to be passed through the scheduler.
* @param[in] QUEUE_SIZE Number of entries in scheduler queue (i.e. the maximum number of events
* that can be scheduled for execution).
*
* @note Since this macro allocates a buffer, it must only be called once (it is OK to call it
* several times as long as it is from the same location, e.g. to do a reinitialization).
*/
#define APP_SCHED_INIT(EVENT_SIZE, QUEUE_SIZE) \
do \
{ \
static uint32_t APP_SCHED_BUF[CEIL_DIV(APP_SCHED_BUF_SIZE((EVENT_SIZE), (QUEUE_SIZE)), \
sizeof(uint32_t))]; \
uint32_t ERR_CODE = app_sched_init((EVENT_SIZE), (QUEUE_SIZE), APP_SCHED_BUF); \
APP_ERROR_CHECK(ERR_CODE); \
} while (0)
/**@brief Function for initializing the Scheduler.
*
* @details It must be called before entering the main loop.
*
* @param[in] max_event_size Maximum size of events to be passed through the scheduler.
* @param[in] queue_size Number of entries in scheduler queue (i.e. the maximum number of
* events that can be scheduled for execution).
* @param[in] p_evt_buffer Pointer to memory buffer for holding the scheduler queue. It must
* be dimensioned using the APP_SCHED_BUFFER_SIZE() macro. The buffer
* must be aligned to a 4 byte boundary.
*
* @note Normally initialization should be done using the APP_SCHED_INIT() macro, as that will both
* allocate the scheduler buffer, and also align the buffer correctly.
*
* @retval NRF_SUCCESS Successful initialization.
* @retval NRF_ERROR_INVALID_PARAM Invalid parameter (buffer not aligned to a 4 byte
* boundary).
*/
uint32_t app_sched_init(uint16_t max_event_size, uint16_t queue_size, void * p_evt_buffer);
/**@brief Function for executing all scheduled events.
*
* @details This function must be called from within the main loop. It will execute all events
* scheduled since the last time it was called.
*/
void app_sched_execute(void);
/**@brief Function for scheduling an event.
*
* @details Puts an event into the event queue.
*
* @param[in] p_event_data Pointer to event data to be scheduled.
* @param[in] event_size Size of event data to be scheduled.
* @param[in] handler Event handler to receive the event.
*
* @return NRF_SUCCESS on success, otherwise an error code.
*/
uint32_t app_sched_event_put(void * p_event_data,
uint16_t event_size,
app_sched_event_handler_t handler);
#ifdef APP_SCHEDULER_WITH_PAUSE
/**@brief A function to pause the scheduler.
*
* @details When the scheduler is paused events are not pulled from the scheduler queue for
* processing. The function can be called multiple times. To unblock the scheduler the
* function @ref app_sched_resume has to be called the same number of times.
*/
void app_sched_pause(void);
/**@brief A function to resume a scheduler.
*
* @details To unblock the scheduler this function has to be called the same number of times as
* @ref app_sched_pause function.
*/
void app_sched_resume(void);
#endif
#endif // APP_SCHEDULER_H__
/** @} */
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