Diff: nordic-sdk/components/libraries/scheduler/app_scheduler.h

Revision:

103:138bdc859cc9

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+++ b/nordic-sdk/components/libraries/scheduler/app_scheduler.h	Wed Apr 15 08:59:11 2015 +0100
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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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