Diff: events/equeue/equeue_platform.h

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/events/equeue/equeue_platform.h	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,145 @@
+
+/** \addtogroup events */
+/** @{*/
+/*
+ * System specific implementation
+ *
+ * Copyright (c) 2016 Christopher Haster
+ *
+ * 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.
+ */
+#ifndef EQUEUE_PLATFORM_H
+#define EQUEUE_PLATFORM_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdbool.h>
+
+// Currently supported platforms
+//
+// Uncomment to select a supported platform or reimplement this file
+// for a specific target.
+//#define EQUEUE_PLATFORM_POSIX
+//#define EQUEUE_PLATFORM_MBED
+
+// Try to infer a platform if none was manually selected
+#if !defined(EQUEUE_PLATFORM_POSIX)     \
+ && !defined(EQUEUE_PLATFORM_MBED)
+#if defined(__unix__)
+#define EQUEUE_PLATFORM_POSIX
+#elif defined(__MBED__)
+#define EQUEUE_PLATFORM_MBED
+#else
+#warning "Unknown platform! Please update equeue_platform.h"
+#endif
+#endif
+
+// Platform includes
+#if defined(EQUEUE_PLATFORM_POSIX)
+#include <pthread.h>
+#endif
+
+
+// Platform millisecond counter
+//
+// Return a tick that represents the number of milliseconds that have passed
+// since an arbitrary point in time. The granularity does not need to be at
+// the millisecond level, however the accuracy of the equeue library is
+// limited by the accuracy of this tick.
+//
+// Must intentionally overflow to 0 after 2^32-1
+unsigned equeue_tick(void);
+
+
+// Platform mutex type
+//
+// The equeue library requires at minimum a non-recursive mutex that is
+// safe in interrupt contexts. The mutex section is help for a bounded
+// amount of time, so simply disabling interrupts is acceptable
+//
+// If irq safety is not required, a regular blocking mutex can be used.
+#if defined(EQUEUE_PLATFORM_POSIX)
+typedef pthread_mutex_t equeue_mutex_t;
+#elif defined(EQUEUE_PLATFORM_WINDOWS)
+typedef CRITICAL_SECTION equeue_mutex_t;
+#elif defined(EQUEUE_PLATFORM_MBED)
+typedef unsigned equeue_mutex_t;
+#elif defined(EQUEUE_PLATFORM_FREERTOS)
+typedef UBaseType_t equeue_mutex_t;
+#endif
+
+// Platform mutex operations
+//
+// The equeue_mutex_create and equeue_mutex_destroy manage the lifetime
+// of the mutex. On error, equeue_mutex_create should return a negative
+// error code.
+//
+// The equeue_mutex_lock and equeue_mutex_unlock lock and unlock the
+// underlying mutex.
+int equeue_mutex_create(equeue_mutex_t *mutex);
+void equeue_mutex_destroy(equeue_mutex_t *mutex);
+void equeue_mutex_lock(equeue_mutex_t *mutex);
+void equeue_mutex_unlock(equeue_mutex_t *mutex);
+
+
+// Platform semaphore type
+//
+// The equeue library requires a binary semaphore type that can be safely
+// signaled from interrupt contexts and from inside a equeue_mutex section.
+//
+// The equeue_signal_wait is relied upon by the equeue library to sleep the
+// processor between events. Spurious wakeups have no negative-effects.
+//
+// A counting semaphore will also work, however may cause the event queue
+// dispatch loop to run unnecessarily. For that matter, equeue_signal_wait
+// may even be implemented as a single return statement.
+#if defined(EQUEUE_PLATFORM_POSIX)
+typedef struct equeue_sema {
+    pthread_mutex_t mutex;
+    pthread_cond_t cond;
+    bool signal;
+} equeue_sema_t;
+#elif defined(EQUEUE_PLATFORM_MBED) && defined(MBED_CONF_RTOS_PRESENT)
+typedef unsigned equeue_sema_t[8];
+#elif defined(EQUEUE_PLATFORM_MBED)
+typedef volatile int equeue_sema_t;
+#endif
+
+// Platform semaphore operations
+//
+// The equeue_sema_create and equeue_sema_destroy manage the lifetime
+// of the semaphore. On error, equeue_sema_create should return a negative
+// error code.
+//
+// The equeue_sema_signal marks a semaphore as signalled such that the next
+// equeue_sema_wait will return true.
+//
+// The equeue_sema_wait waits for a semaphore to be signalled or returns
+// immediately if equeue_sema_signal had been called since the last
+// equeue_sema_wait. The equeue_sema_wait returns true if it detected that
+// equeue_sema_signal had been called.
+int equeue_sema_create(equeue_sema_t *sema);
+void equeue_sema_destroy(equeue_sema_t *sema);
+void equeue_sema_signal(equeue_sema_t *sema);
+bool equeue_sema_wait(equeue_sema_t *sema, int ms);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+/** @}*/