Diff: nordic/app_common/app_scheduler.c

Revision:

46:2bfbbe290083

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nordic/app_common/app_scheduler.c	Wed Jul 16 10:54:22 2014 +0100
@@ -0,0 +1,179 @@
+/* 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.
+ *
+ */
+
+#include "app_scheduler.h"
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include "nrf_soc.h"
+#include "nrf_assert.h"
+#include "app_util.h"
+#include "app_util_platform.h"
+
+/**@brief Structure for holding a scheduled event header. */
+typedef struct
+{
+    app_sched_event_handler_t handler;          /**< Pointer to event handler to receive the event. */
+    uint16_t                  event_data_size;  /**< Size of event data. */
+} event_header_t;
+
+STATIC_ASSERT(sizeof(event_header_t) <= APP_SCHED_EVENT_HEADER_SIZE);
+
+static event_header_t * m_queue_event_headers;  /**< Array for holding the queue event headers. */
+static uint8_t        * m_queue_event_data;     /**< Array for holding the queue event data. */
+static volatile uint8_t m_queue_start_index;    /**< Index of queue entry at the start of the queue. */
+static volatile uint8_t m_queue_end_index;      /**< Index of queue entry at the end of the queue. */
+static uint16_t         m_queue_event_size;     /**< Maximum event size in queue. */
+static uint16_t         m_queue_size;           /**< Number of queue entries. */
+
+/**@brief Macro for checking if a queue is full. */
+#define APP_SCHED_QUEUE_FULL() (next_index(m_queue_end_index) == m_queue_start_index)
+
+/**@brief Macro for checking if a queue is empty. */
+#define APP_SCHED_QUEUE_EMPTY() (m_queue_end_index == m_queue_start_index)
+
+
+/**@brief Function for incrementing a queue index, and handle wrap-around.
+ *
+ * @param[in]   index   Old index.
+ *
+ * @return      New (incremented) index.
+ */
+static __INLINE uint8_t next_index(uint8_t index)
+{
+    return (index < m_queue_size) ? (index + 1) : 0;
+}
+
+
+uint32_t app_sched_init(uint16_t event_size, uint16_t queue_size, void * p_event_buffer)
+{
+    uint16_t data_start_index = (queue_size + 1) * sizeof(event_header_t);
+
+    // Check that buffer is correctly aligned
+    if (!is_word_aligned(p_event_buffer))
+    {
+        return NRF_ERROR_INVALID_PARAM;
+    }
+
+    // Initialize event scheduler
+    m_queue_event_headers = p_event_buffer;
+    m_queue_event_data    = &((uint8_t *)p_event_buffer)[data_start_index];
+    m_queue_end_index     = 0;
+    m_queue_start_index   = 0;
+    m_queue_event_size    = event_size;
+    m_queue_size          = queue_size;
+
+    return NRF_SUCCESS;
+}
+
+
+uint32_t app_sched_event_put(void                    * p_event_data,
+                             uint16_t                  event_data_size,
+                             app_sched_event_handler_t handler)
+{
+    uint32_t err_code;
+
+    if (event_data_size <= m_queue_event_size)
+    {
+        uint16_t event_index = 0xFFFF;
+
+        CRITICAL_REGION_ENTER();
+
+        if (!APP_SCHED_QUEUE_FULL())
+        {
+            event_index       = m_queue_end_index;
+            m_queue_end_index = next_index(m_queue_end_index);
+        }
+
+        CRITICAL_REGION_EXIT();
+
+        if (event_index != 0xFFFF)
+        {
+            // NOTE: This can be done outside the critical region since the event consumer will
+            //       always be called from the main loop, and will thus never interrupt this code.
+            m_queue_event_headers[event_index].handler = handler;
+            if ((p_event_data != NULL) && (event_data_size > 0))
+            {
+                memcpy(&m_queue_event_data[event_index * m_queue_event_size],
+                       p_event_data,
+                       event_data_size);
+                m_queue_event_headers[event_index].event_data_size = event_data_size;
+            }
+            else
+            {
+                m_queue_event_headers[event_index].event_data_size = 0;
+            }
+
+            err_code = NRF_SUCCESS;
+        }
+        else
+        {
+            err_code = NRF_ERROR_NO_MEM;
+        }
+    }
+    else
+    {
+        err_code = NRF_ERROR_INVALID_LENGTH;
+    }
+
+    return err_code;
+}
+
+
+/**@brief Function for reading the next event from specified event queue.
+ *
+ * @param[out]  pp_event_data       Pointer to pointer to event data.
+ * @param[out]  p_event_data_size   Pointer to size of event data.
+ * @param[out]  p_event_handler     Pointer to event handler function pointer.
+ *
+ * @return      NRF_SUCCESS if new event, NRF_ERROR_NOT_FOUND if event queue is empty.
+ */
+static uint32_t app_sched_event_get(void                     ** pp_event_data,
+                                    uint16_t *                  p_event_data_size,
+                                    app_sched_event_handler_t * p_event_handler)
+{
+    uint32_t err_code = NRF_ERROR_NOT_FOUND;
+
+    if (!APP_SCHED_QUEUE_EMPTY())
+    {
+        uint16_t event_index;
+
+        // NOTE: There is no need for a critical region here, as this function will only be called
+        //       from app_sched_execute() from inside the main loop, so it will never interrupt
+        //       app_sched_event_put(). Also, updating of (i.e. writing to) the start index will be
+        //       an atomic operation.
+        event_index         = m_queue_start_index;
+        m_queue_start_index = next_index(m_queue_start_index);
+
+        *pp_event_data     = &m_queue_event_data[event_index * m_queue_event_size];
+        *p_event_data_size = m_queue_event_headers[event_index].event_data_size;
+        *p_event_handler   = m_queue_event_headers[event_index].handler;
+
+        err_code = NRF_SUCCESS;
+    }
+
+    return err_code;
+}
+
+
+void app_sched_execute(void)
+{
+    void                    * p_event_data;
+    uint16_t                  event_data_size;
+    app_sched_event_handler_t event_handler;
+
+    // Get next event (if any), and execute handler
+    while ((app_sched_event_get(&p_event_data, &event_data_size, &event_handler) == NRF_SUCCESS))
+    {
+        event_handler(p_event_data, event_data_size);
+    }
+}