Minimal C RTOS API

Author: kjbracey

rtos/rtos_c.cpp

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+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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.
+ */
+
+#include "rtos/rtos_c.h"
+#include "rtos/Kernel.h"
+#include "rtos/ThisThread.h"
+
+extern "C" {
+
+uint64_t get_ms_count(void)
+{
+    return rtos::Kernel::get_ms_count();
+}
+
+void thread_sleep_for(uint32_t millisec)
+{
+    return rtos::ThisThread::sleep_for(millisec);
+}
+
+void thread_sleep_until(uint64_t millisec)
+{
+    return rtos::ThisThread::sleep_until(millisec);
+
+}
+
+}

rtos/rtos_c.h

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+/*
+ * Copyright (c) 2019 ARM Limited. All rights reserved.
+ */
+
+#ifndef MBED_RTOS_C_H_
+#define MBED_RTOS_C_H_
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Generic thread functions.
+ *
+ * These are C versions of functions provided in C++ via rtos::Thread and rtos::ThisThread
+ */
+
+/** Read the current RTOS kernel millisecond tick count.
+     The tick count corresponds to the tick count the RTOS uses for timing
+     purposes. It increments monotonically from 0 at boot, so it effectively
+     never wraps. If the underlying RTOS only provides a 32-bit tick count,
+     this method expands it to 64 bits.
+     @return  RTOS kernel current tick count
+     @note Mbed OS always uses millisecond RTOS ticks, and this could only wrap
+           after half a billion years.
+     @note In a non-RTOS build, this computes an equivalent time in milliseconds,
+           based on a HAL timer. The time may be referenced as 0 on first call.
+     @note You cannot call this function from ISR context.
+    @note The equivalent functionality is accessible in C++ via rtos::Kernel::get_ms_count.
+ */
+uint64_t get_ms_count(void);
+
+/** Sleep for a specified time period in millisec:
+  @param   millisec  time delay value
+  @note You cannot call this function from ISR context.
+  @note The equivalent functionality is accessible in C++ via rtos::ThisThread::sleep_for.
+*/
+void thread_sleep_for(uint32_t millisec);
+
+/** Sleep until a specified time in millisec
+  The specified time is according to Kernel::get_ms_count().
+  @param   millisec absolute time in millisec
+  @note You cannot call this function from ISR context.
+  @note if millisec is equal to or lower than the current tick count, this
+        returns immediately.
+  @note The equivalent functionality is accessible in C++ via ThisThread::sleep_until.
+*/
+void thread_sleep_until(uint64_t millisec);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MBED_THREAD_API_H_ */