add event-driven framework

see examples/event_driven_at_module and examples/event_driven_hello_world, demo project: TencentOS-tiny\board\TencentOS_tiny_EVB_MX\KEIL\event_driven_hello_world

kernel/evtdrv/include/tos_evtdrv_sys.h

@@ -0,0 +1,37 @@
+#ifndef _TOS_EVTDRV_SYS_H_
+#define  _TOS_EVTDRV_SYS_H_
+
+#if TOS_CFG_EVENT_DRIVEN_EN > 0u
+
+typedef void (*k_evtdrv_poll_t)(void);
+
+/**
+ * @brief Initialize the event-driven system.
+ *
+ * @attention event-driven is a simplified schedule model to support the none-context-swith-based multi-task programming.("the big while 1")
+ * must enable TOS_CFG_MMHEAP_EN to use event-driven.
+ *
+ * @param[in]   tasks               array of the tasks.
+ * @param[in]   task_table_size     size of the tasks.
+ * @param[in]   poll                the user defined poll function.
+ *
+ * @return  errcode
+ * @retval  #EVTDRV_ERR_MMHEAP_NOT_ENABLED    mmheap is not enabled.
+ * @retval  #EVTDRV_ERR_MEM_ALLOC_FAILED      memory allocate failed.
+ * @retval  #EVTDRV_ERR_NONE                  initialize successfully.
+ */
+__API__ evtdrv_err_t tos_evtdrv_sys_init(evtdrv_task_entry_t tasks[], evtdrv_ttb_sz_t task_table_size, k_evtdrv_poll_t poll);
+
+/**
+ * @brief Start the event-driven system.
+ *
+ * @attention start the event-driven multi-task "schedule".
+ *
+ * @return  None
+ */
+__API__ void tos_evtdrv_sys_start(void);
+
+#endif /* TOS_CFG_EVENT_DRIVEN_EN */
+
+#endif /* _TOS_EVTDRV_SYS_H_ */
+