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diff --git a/ada_user/initialization_manager.rst b/ada_user/initialization_manager.rst deleted file mode 100644 index b6864f1..0000000 --- a/ada_user/initialization_manager.rst +++ /dev/null @@ -1,280 +0,0 @@ -Initialization Manager -###################### - -Introduction -============ - -The Initialization Manager is responsible for -initiating and shutting down RTEMS. Initiating RTEMS involves -creating and starting all configured initialization tasks, and -for invoking the initialization routine for each user-supplied -device driver. In a multiprocessor configuration, this manager -also initializes the interprocessor communications layer. The -directives provided by the Initialization Manager are: - -- ``rtems.initialize_executive`` - Initialize RTEMS - -- ``rtems.shutdown_executive`` - Shutdown RTEMS - -Background -========== - -Initialization Tasks --------------------- -.. index:: initialization tasks - -Initialization task(s) are the mechanism by which -RTEMS transfers initial control to the user’s application. -Initialization tasks differ from other application tasks in that -they are defined in the User Initialization Tasks Table and -automatically created and started by RTEMS as part of its -initialization sequence. Since the initialization tasks are -scheduled using the same algorithm as all other RTEMS tasks, -they must be configured at a priority and mode which will ensure -that they will complete execution before other application tasks -execute. Although there is no upper limit on the number of -initialization tasks, an application is required to define at -least one. - -A typical initialization task will create and start -the static set of application tasks. It may also create any -other objects used by the application. Initialization tasks -which only perform initialization should delete themselves upon -completion to free resources for other tasks. Initialization -tasks may transform themselves into a "normal" application task. -This transformation typically involves changing priority and -execution mode. RTEMS does not automatically delete the -initialization tasks. - -System Initialization ---------------------- - -System Initialization begins with board reset and continues -through RTEMS initialization, initialization of all device -drivers, and eventually a context switch to the first user -task. Remember, that interrupts are disabled during -initialization and the *initialization context* is not -a task in any sense and the user should be very careful -during initialization. - -The BSP must ensure that the there is enough stack -space reserved for the initialization context to -successfully execute the initialization routines for -all device drivers and, in multiprocessor configurations, the -Multiprocessor Communications Interface Layer initialization -routine. - -The Idle Task -------------- - -The Idle Task is the lowest priority task in a system -and executes only when no other task is ready to execute. This -default implementation of this task consists of an infinite -loop. RTEMS allows the Idle Task body to be replaced by a CPU -specific implementation, a BSP specific implementation or an -application specific implementation. - -The Idle Task is preemptible and *WILL* be preempted when -any other task is made ready to execute. This characteristic is -critical to the overall behavior of any application. - -Initialization Manager Failure ------------------------------- - -The ``rtems.fatal_error_occurred`` directive will -be invoked from ``rtems.initialize_executive`` -for any of the following reasons: - -- If either the Configuration Table or the CPU Dependent - Information Table is not provided. - -- If the starting address of the RTEMS RAM Workspace, - supplied by the application in the Configuration Table, is NULL - or is not aligned on a four-byte boundary. - -- If the size of the RTEMS RAM Workspace is not large - enough to initialize and configure the system. - -- If the interrupt stack size specified is too small. - -- If multiprocessing is configured and the node entry in - the Multiprocessor Configuration Table is not between one and - the maximum_nodes entry. - -- If a multiprocessor system is being configured and no - Multiprocessor Communications Interface is specified. - -- If no user initialization tasks are configured. At - least one initialization task must be configured to allow RTEMS - to pass control to the application at the end of the executive - initialization sequence. - -- If any of the user initialization tasks cannot be - created or started successfully. - -A discussion of RTEMS actions when a fatal error occurs -may be found `Announcing a Fatal Error`_ - -Operations -========== - -Initializing RTEMS ------------------- - -The Initialization Manager ``rtems.initialize_executive`` -directives is called by the ``boot_card`` routine. The ``boot_card`` -routine is invoked by the Board Support Package once a basic C run-time -environment is set up. This consists of - -- a valid and accessible text section, read-only data, read-write data and - zero-initialized data, - -- an initialization stack large enough to initialize the rest of the Board - Support Package, RTEMS and the device drivers, - -- all registers and components mandated by Application Binary Interface, and - -- disabled interrupts. - -The ``rtems.initialize_executive`` directive uses a system -initialization linker set to initialize only those parts of the overall RTEMS -feature set that is necessary for a particular application. See `Linker Sets`_. -Each RTEMS feature used the application may optionally register an -initialization handler. The system initialization API is available via``#included <rtems/sysinit.h>``. - -A list of all initialization steps follows. Some steps are optional depending -on the requested feature set of the application. The initialization steps are -execute in the order presented here. - -:dfn:`RTEMS_SYSINIT_BSP_WORK_AREAS` - The work areas consisting of C Program Heap and the RTEMS Workspace are - initialized by the Board Support Package. This step is mandatory. - -:dfn:`RTEMS_SYSINIT_BSP_START` - Basic initialization step provided by the Board Support Package. This step is - mandatory. - -:dfn:`RTEMS_SYSINIT_DATA_STRUCTURES` - This directive is called when the Board Support Package has completed its basic - initialization and allows RTEMS to initialize the application environment based - upon the information in the Configuration Table, User Initialization Tasks - Table, Device Driver Table, User Extension Table, Multiprocessor Configuration - Table, and the Multiprocessor Communications Interface (MPCI) Table. - -:dfn:`RTEMS_SYSINIT_BSP_LIBC` - Depending on the application configuration the IO library and root filesystem - is initialized. This step is mandatory. - -:dfn:`RTEMS_SYSINIT_BEFORE_DRIVERS` - This directive performs initialization that must occur between basis RTEMS data - structure initialization and device driver initialization. In particular, in a - multiprocessor configuration, this directive will create the MPCI Server Task. - -:dfn:`RTEMS_SYSINIT_BSP_PRE_DRIVERS` - Initialization step performed right before device drivers are initialized - provided by the Board Support Package. This step is mandatory. - -:dfn:`RTEMS_SYSINIT_DEVICE_DRIVERS` - This step initializes all statically configured device drivers and performs all - RTEMS initialization which requires device drivers to be initialized. This - step is mandatory. - In a multiprocessor configuration, this service will initialize the - Multiprocessor Communications Interface (MPCI) and synchronize with the other - nodes in the system. - -:dfn:`RTEMS_SYSINIT_BSP_POST_DRIVERS` - Initialization step performed right after device drivers are initialized - provided by the Board Support Package. This step is mandatory. - -The final action of the ``rtems.initialize_executive`` directive -is to start multitasking. RTEMS does not return to the initialization context -and the initialization stack may be re-used for interrupt processing. - -Many of RTEMS actions during initialization are based upon -the contents of the Configuration Table. For more information -regarding the format and contents of this table, please refer -to the chapter `Configuring a System`_. - -The final action in the initialization sequence is the -initiation of multitasking. When the scheduler and dispatcher -are enabled, the highest priority, ready task will be dispatched -to run. Control will not be returned to the Board Support -Package after multitasking is enabled. The initialization stack may be re-used -for interrupt processing. - -Shutting Down RTEMS -------------------- - -The ``rtems.shutdown_executive`` directive is invoked by the -application to end multitasking and terminate the system. - -Directives -========== - -This section details the Initialization Manager’s -directives. A subsection is dedicated to each of this manager’s -directives and describes the calling sequence, related -constants, usage, and status codes. - -INITIALIZE_EXECUTIVE - Initialize RTEMS ---------------------------------------- -.. index:: initialize RTEMS -.. index:: start multitasking - -**CALLING SEQUENCE:** - -.. code:: c - - NOT SUPPORTED FROM Ada BINDING - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -Iterates through the system initialization linker set and invokes the -registered handlers. The final step is to start multitasking. - -**NOTES:** - -This directive should be called by ``boot_card`` only. - -This directive *does not return* to the caller. Errors in the initialization -sequence are usually fatal and lead to a system termination. - -SHUTDOWN_EXECUTIVE - Shutdown RTEMS ------------------------------------ -.. index:: shutdown RTEMS - -**CALLING SEQUENCE:** - -.. code:: c - - procedure Shutdown_Executive( - Status : in RTEMS.Unsigned32 - ); - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -This directive is called when the application wishes to shutdown RTEMS. The -system is terminated with a fatal source of ``RTEMS_FATAL_SOURCE_EXIT`` and -the specified ``result`` code. - -**NOTES:** - -This directive *must* be the last RTEMS directive -invoked by an application and it *does not return* to the caller. - -This directive may be called any time. - -.. COMMENT: COPYRIGHT (c) 1988-2014. - -.. COMMENT: On-Line Applications Research Corporation (OAR). - -.. COMMENT: All rights reserved. - |