| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| |
| /** |
| * @addtogroup OSKernel |
| * @{ |
| * @defgroup OSMutex Mutexes |
| * @{ |
| */ |
| |
| #ifndef _OS_MUTEX_H_ |
| #define _OS_MUTEX_H_ |
| |
| #include "os/os.h" |
| #include "os/queue.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** |
| * OS mutex structure |
| */ |
| struct os_mutex { |
| SLIST_HEAD(, os_task) mu_head; |
| uint8_t _pad; |
| /** Mutex owner's default priority */ |
| uint8_t mu_prio; |
| /** Mutex call nesting level */ |
| uint16_t mu_level; |
| /** Task that owns the mutex */ |
| struct os_task *mu_owner; |
| }; |
| |
| /* |
| XXX: NOTES |
| -> Should we add a magic number or flag to the mutex structure so |
| that we know that this is a mutex? We can use it for double checking |
| that a proper mutex was passed in to the API. |
| -> What debug information should we add to this structure? Who last |
| acquired the mutex? File/line where it was released? |
| -> Should we add a name to the mutex? |
| -> Should we add a "os_mutex_inspect() api? |
| */ |
| |
| /* XXX: api to create |
| os_mutex_inspect(); |
| */ |
| |
| /** |
| * Create a mutex and initialize it. |
| * |
| * @param mu Pointer to mutex |
| * |
| * @return os_error_t |
| * OS_INVALID_PARM Mutex passed in was NULL. |
| * OS_OK no error. |
| */ |
| os_error_t os_mutex_init(struct os_mutex *mu); |
| |
| /** |
| * Release a mutex. |
| * |
| * @param mu Pointer to the mutex to be released |
| * |
| * @return os_error_t |
| * OS_INVALID_PARM Mutex passed in was NULL. |
| * OS_BAD_MUTEX Mutex was not granted to current task (not owner). |
| * OS_OK No error |
| */ |
| os_error_t os_mutex_release(struct os_mutex *mu); |
| |
| /** |
| * Pend (wait) for a mutex. |
| * |
| * @param mu Pointer to mutex. |
| * @param timeout Timeout, in os ticks. |
| * A timeout of 0 means do not wait if not available. |
| * A timeout of OS_TIMEOUT_NEVER means wait forever. |
| * |
| * |
| * @return os_error_t |
| * OS_INVALID_PARM Mutex passed in was NULL. |
| * OS_TIMEOUT Mutex was owned by another task and timeout=0 |
| * OS_OK no error. |
| */ |
| os_error_t os_mutex_pend(struct os_mutex *mu, os_time_t timeout); |
| |
| /** |
| * Get mutex lock count. |
| * |
| * @note Function should be called from task owning the mutex (one that |
| * successfully called os_mutex_pend). Calling function from other task |
| * that does not own the mutex will return value that has little value |
| * to the caller since value can change at any time by other task. |
| * |
| * It can also be called from interrupt context to check if given mutex |
| * is taken. |
| * |
| * @param mu Pointer to mutex. |
| * |
| * @return number of times lock was called from current task |
| */ |
| static inline uint16_t os_mutex_get_level(struct os_mutex *mu) |
| { |
| return mu->mu_level; |
| } |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* _OS_MUTEX_H_ */ |
| |
| /** |
| * @} OSMutex |
| * @} OSKernel |
| */ |