Dependents: rtest LeonardoMbos OS_test Labo_TRSE_Drone ... more
mbos.h
- Committer:
- AndrewL
- Date:
- 2010-12-05
- Revision:
- 3:6cb5413f143f
- Parent:
- 2:af930cdf7cce
- Child:
- 4:e740e08cbea9
File content as of revision 3:6cb5413f143f:
/*********************************************************************************** * m b o s R T O S F O R m b e d (ARM CORTEX M3) * * Copyright (c) 2010 - 2011 Andrew Levido * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef MBOS_H #define MBOS_H typedef unsigned int uint; /**A pre-emptive, mutlitasking real-time operating system for mbed applications. * * Allows the user to write their application in the form of independant tasks. * The operating system manages a completely separate processor context for each * task (processor registers and stack) and swaps between the tasks according to a * simple scheduling algorithm. * * Tasks are allocated a priority, and the scheduler ensures that the task * that with the highest priority that is not waiting for an event, has control of * the processor. If more than one task shares the highest priority, they will be * run sequentially in round-robin fashion. * * Each task may wait for one or more of up to 32 different events, each represented by * one bit in the event flags word. Events may be posted by another task, by a mbos * timer, or in response to some asynchronous event such as an peripheral interrupt. * * mbos implements the SysTick timer to generate a System Tick every millisecond. * Scheduling occurs once every Tick, or whenever a task blocks or an event is posted. * The user may create one-shot or continuous timers to post events to tasks. * * mbos implements a simple ceiling protocol resource locking mechanism To manage access * to system resources. Tasks may take exclusive ownership of resources for a period. * * A typical simple example with two tasks, and one timer, might look like this: * @code * #include "mbed.h" * #include "mbos.h" * * #define TASK1_ID 1 // defines to make the code more readable * #define TASK1_PRIO 50 * #define TASK1_STACK_SZ 32 * #define TASK2_ID 2 * #define TASK2_PRIO 60 * #define TASK2_STACK_SZ 32 * #define TIMER0_ID 0 * #define TIMER0_PERIOD 1000 * #define TIMER0_EVENT 1 * #define T1_TO_T2_EVENT 2 * * void task1(void); // task function prototypes * void task2(void); * * DigitalOut led1(LED1); * DigitalOut led2(LED2); * mbos os(2, 1); // 2 tasks, 1 timer * * int main(void) * { * os.CreateTask(TASK1_ID, TASK1_PRIO, TASK1_STACK_SZ, task1); * os.CreateTask(TASK2_ID, TASK2_PRIO, TASK2_STACK_SZ, task2); * os.CreateTimer(TIMER0_ID, TIMER0_EVENT, TASK1_ID); * os.Start(); * // never get here! * } * void task1(void) * { * os.SetTimer(TIMER0_ID, TIMER0_PERIOD, TIMER0_PERIOD); * while(1){ * os.WaitEvent(TIMER0_EVENT); * led1 = !led1; * os.SetEvent(T1_TO_T2_EVENT, TASK2_ID); * } * } * void task2(void) * { * while(1){ * os.WaitEvent(T1_TO_T2_EVENT); * led2 = 1; * wait_ms(100); * led2 = 0; * } * } * @endcode */ class mbos { public: /** Create an mbos object. Instantiate mbos and define the number of tasks, timers * and resources. * * @param ntasks The number of user tasks (1 .. 99). * @param ntimers Optional number of timers (0 .. 100). * @param nresources Optional number of resources (0 .. 100). */ mbos(uint ntasks, uint ntimers = 0, uint nresources = 0); /** Start mbos. Optionally specify the size of the stack for a user-written idle task. * All tasks, timers and resources must be created before calling Start. * * @param idlestacksize Size in words (>= 32) of the user-written idle task if present. * @returns Never returns */ void Start(uint idlestacksize = 0); /** Create an mbos task. Allocates and initialises data structures for the task. * * @param taskid Unique ID for the task. (1 .. ntasks). * @param priority Priority (0 .. 99) of the task. Tasks may share the same priority. * @param stacksize Size in words (>= 32) of the task's stack. * @param fun Pointer to the task function. Function must be of type static void, * and must return nothing. */ void CreateTask(uint taskid, uint priority, uint stacksz, void (*fun)(void)); /** Get the ID of the current task. * * @returns The ID (0 .. 99) of the calling task. */ uint GetTask(void); /** Set the priority of the current task. Does nothing if called from the idle task. * * @param priority Priority (0 .. 99) to apply to the calling task. */ void SetPriority(uint priority); /** Get the priority of the current task. * * @returns The priority (0 .. 99) of the calling task. */ uint GetPriority(void); /** Wait for an event or events. Causes the current task to block, waiting for the * specified event. Does nothing if called from the idle task, or if the event is NULL. * * @param event Event flag(s) to wait for. */ void WaitEvent(uint event); /** Post an event or events to a task. * Posts the nominated event(s) to the specified task. Forces a context switch if the events * are posted successfully. Does nothing if the task is not waiting, or is not waiting for * the posted event. * * @param event Event flag(s) to post. * @param task The ID of the task to which to post the event(s). May not be idle task. */ void SetEvent(uint event, uint task); /** Returns the event flag(s) which last caused the task to unblock. * * @returns The event flags. */ uint GetEvent(void); /** Create a mbos timer. Allocates and initialises the data structures for the timer. * * @param timerid Unique ID for the timer (0 .. ntimers - 1). * @param taskid The ID of the task to which the timer will post events. May not be * the idle task. * @param event The event flag(s) that the timer should post on timeout. May not be NULL. */ void CreateTimer(uint timerid, uint taskid, uint event); /** Starts an mbos timer. If the reload time is zero or omitted, the timer will be reset * once it has posted a single event, after time milliseconds. If the reload time is * non-zero, this value will be loaded into the timer on time-out, and the timer will * continue indefinitely. In this case the interval to the first event will be time, * and the interval between subsequent events will be reloadtime. * * @param timerid The ID of the timer. * @param time The period in milliseconds before the timer times out. * @param reload The optional time to reload into the timer when it times out. */ void SetTimer(uint timerid, uint time, uint reload = 0); /** Stops and clears an mbos timer. * * @param timerid The ID of the timer to clear. */ void ClearTimer(uint timerid); /** Creates an mbos resource. Allocates and initialises the data structures for the Resource. * * @param resourceid Unique ID for the resource (0 .. nresource). * @param priority Priority of the resource (normally > than that of any task using the * resource). */ void CreateResource(uint resourceid, uint priority); /** Locks an mbos resource and temporarily allocates the resource's priority to the calling * task. * Does nothing if the resource is already locked, or if called from the idle task. * * @param resourceid The ID of the resource to lock. * @returns Zero if the resource was locked successfully, or the ID of the task that is * currently locking the resource, if not. */ uint LockResource(uint resourceid); /** Tests whether a resource is locked or free, without changing its state. * * @param resourceid The ID of the resouce to test. * @returns Zero if the resource is free, or the ID of the task that is currently * locking the resouce , if not. */ uint TestResource(uint resourceid); /** Frees a resource * Frees an mbos resource and restores the calling task's original priority. Does nothing * if the resource is already free, if called from the idle task, or the resource was * locked by a different task. * * @param resourceid The ID of the resource t free. * @returns Zero if the resource was freed successfully, or the ID of the task that is * locking the resource, if not. */ uint FreeResource(uint resource); private: uint* _initstack(uint *stack, void (*fun)()); }; #endif