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diff --git a/ada_user/interrupt_manager.rst b/ada_user/interrupt_manager.rst deleted file mode 100644 index bcc45dd..0000000 --- a/ada_user/interrupt_manager.rst +++ /dev/null @@ -1,555 +0,0 @@ -Interrupt Manager -################# - -Introduction -============ - -Any real-time executive must provide a mechanism for -quick response to externally generated interrupts to satisfy the -critical time constraints of the application. The interrupt -manager provides this mechanism for RTEMS. This manager permits -quick interrupt response times by providing the critical ability -to alter task execution which allows a task to be preempted upon -exit from an ISR. The interrupt manager includes the following -directive: - -- ``rtems.interrupt_catch`` - Establish an ISR - -- ``rtems.interrupt_disable`` - Disable Interrupts - -- ``rtems.interrupt_enable`` - Enable Interrupts - -- ``rtems.interrupt_flash`` - Flash Interrupt - -- ``rtems.interrupt_local_disable`` - Disable Interrupts on Current Processor - -- ``rtems.interrupt_local_enable`` - Enable Interrupts on Current Processor - -- ``rtems.interrupt_lock_initialize`` - Initialize an ISR Lock - -- ``rtems.interrupt_lock_acquire`` - Acquire an ISR Lock - -- ``rtems.interrupt_lock_release`` - Release an ISR Lock - -- ``rtems.interrupt_lock_acquire_isr`` - Acquire an ISR Lock from ISR - -- ``rtems.interrupt_lock_release_isr`` - Release an ISR Lock from ISR - -- ``rtems.interrupt_is_in_progress`` - Is an ISR in Progress - -Background -========== - -Processing an Interrupt ------------------------ -.. index:: interrupt processing - -The interrupt manager allows the application to -connect a function to a hardware interrupt vector. When an -interrupt occurs, the processor will automatically vector to -RTEMS. RTEMS saves and restores all registers which are not -preserved by the normal Ada calling convention -for the target -processor and invokes the user’s ISR. The user’s ISR is -responsible for processing the interrupt, clearing the interrupt -if necessary, and device specific manipulation... index:: rtems_vector_number - -The ``rtems.interrupt_catch`` -directive connects a procedure to -an interrupt vector. The vector number is managed using -the ``rtems.vector_number`` data type. - -The interrupt service routine is assumed -to abide by these conventions and have a prototype similar to -the following: - -.. code:: c - - NOT SUPPORTED FROM Ada BINDING - -The vector number argument is provided by RTEMS to -allow the application to identify the interrupt source. This -could be used to allow a single routine to service interrupts -from multiple instances of the same device. For example, a -single routine could service interrupts from multiple serial -ports and use the vector number to identify which port requires -servicing. - -To minimize the masking of lower or equal priority -level interrupts, the ISR should perform the minimum actions -required to service the interrupt. Other non-essential actions -should be handled by application tasks. Once the user’s ISR has -completed, it returns control to the RTEMS interrupt manager -which will perform task dispatching and restore the registers -saved before the ISR was invoked. - -The RTEMS interrupt manager guarantees that proper -task scheduling and dispatching are performed at the conclusion -of an ISR. A system call made by the ISR may have readied a -task of higher priority than the interrupted task. Therefore, -when the ISR completes, the postponed dispatch processing must -be performed. No dispatch processing is performed as part of -directives which have been invoked by an ISR. - -Applications must adhere to the following rule if -proper task scheduling and dispatching is to be performed: - -- ** *The interrupt manager must be used for all ISRs which - may be interrupted by the highest priority ISR which invokes an - RTEMS directive.* - -Consider a processor which allows a numerically low -interrupt level to interrupt a numerically greater interrupt -level. In this example, if an RTEMS directive is used in a -level 4 ISR, then all ISRs which execute at levels 0 through 4 -must use the interrupt manager. - -Interrupts are nested whenever an interrupt occurs -during the execution of another ISR. RTEMS supports efficient -interrupt nesting by allowing the nested ISRs to terminate -without performing any dispatch processing. Only when the -outermost ISR terminates will the postponed dispatching occur. - -RTEMS Interrupt Levels ----------------------- -.. index:: interrupt levels - -Many processors support multiple interrupt levels or -priorities. The exact number of interrupt levels is processor -dependent. RTEMS internally supports 256 interrupt levels which -are mapped to the processor’s interrupt levels. For specific -information on the mapping between RTEMS and the target -processor’s interrupt levels, refer to the Interrupt Processing -chapter of the Applications Supplement document for a specific -target processor. - -Disabling of Interrupts by RTEMS --------------------------------- -.. index:: disabling interrupts - -During the execution of directive calls, critical -sections of code may be executed. When these sections are -encountered, RTEMS disables all maskable interrupts before the -execution of the section and restores them to the previous level -upon completion of the section. RTEMS has been optimized to -ensure that interrupts are disabled for a minimum length of -time. The maximum length of time interrupts are disabled by -RTEMS is processor dependent and is detailed in the Timing -Specification chapter of the Applications Supplement document -for a specific target processor. - -Non-maskable interrupts (NMI) cannot be disabled, and -ISRs which execute at this level MUST NEVER issue RTEMS system -calls. If a directive is invoked, unpredictable results may -occur due to the inability of RTEMS to protect its critical -sections. However, ISRs that make no system calls may safely -execute as non-maskable interrupts. - -Operations -========== - -Establishing an ISR -------------------- - -The ``rtems.interrupt_catch`` -directive establishes an ISR for -the system. The address of the ISR and its associated CPU -vector number are specified to this directive. This directive -installs the RTEMS interrupt wrapper in the processor’s -Interrupt Vector Table and the address of the user’s ISR in the -RTEMS’ Vector Table. This directive returns the previous -contents of the specified vector in the RTEMS’ Vector Table. - -Directives Allowed from an ISR ------------------------------- - -Using the interrupt manager ensures that RTEMS knows -when a directive is being called from an ISR. The ISR may then -use system calls to synchronize itself with an application task. -The synchronization may involve messages, events or signals -being passed by the ISR to the desired task. Directives invoked -by an ISR must operate only on objects which reside on the local -node. The following is a list of RTEMS system calls that may be -made from an ISR: - -- Task Management - Although it is acceptable to operate on the RTEMS_SELF task (e.g. - the currently executing task), while in an ISR, this will refer - to the interrupted task. Most of the time, it is an application - implementation error to use RTEMS_SELF from an ISR. - - rtems_task_suspend - - rtems_task_resume - -- Interrupt Management - - rtems_interrupt_enable - - rtems_interrupt_disable - - rtems_interrupt_flash - - rtems_interrupt_lock_acquire - - rtems_interrupt_lock_release - - rtems_interrupt_lock_acquire_isr - - rtems_interrupt_lock_release_isr - - rtems_interrupt_is_in_progress - - rtems_interrupt_catch - -- Clock Management - - rtems_clock_set - - rtems_clock_get - - rtems_clock_get_tod - - rtems_clock_get_tod_timeval - - rtems_clock_get_seconds_since_epoch - - rtems_clock_get_ticks_per_second - - rtems_clock_get_ticks_since_boot - - rtems_clock_get_uptime - - rtems_clock_set_nanoseconds_extension - - rtems_clock_tick - -- Timer Management - - rtems_timer_cancel - - rtems_timer_reset - - rtems_timer_fire_after - - rtems_timer_fire_when - - rtems_timer_server_fire_after - - rtems_timer_server_fire_when - -- Event Management - - rtems_event_send - - rtems_event_system_send - - rtems_event_transient_send - -- Semaphore Management - - rtems_semaphore_release - -- Message Management - - rtems_message_queue_send - - rtems_message_queue_urgent - -- Signal Management - - rtems_signal_send - -- Dual-Ported Memory Management - - rtems_port_external_to_internal - - rtems_port_internal_to_external - -- IO Management - The following services are safe to call from an ISR if and only if - the device driver service invoked is also safe. The IO Manager itself - is safe but the invoked driver entry point may or may not be. - - rtems_io_initialize - - rtems_io_open - - rtems_io_close - - rtems_io_read - - rtems_io_write - - rtems_io_control - -- Fatal Error Management - - rtems_fatal - - rtems_fatal_error_occurred - -- Multiprocessing - - rtems_multiprocessing_announce - -Directives -========== - -This section details the interrupt 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. - -INTERRUPT_CATCH - Establish an ISR ----------------------------------- -.. index:: establish an ISR -.. index:: install an ISR - -**CALLING SEQUENCE:** - -.. code:: c - - NOT SUPPORTED FROM Ada BINDING - -**DIRECTIVE STATUS CODES:** - -``RTEMS.SUCCESSFUL`` - ISR established successfully -``RTEMS.INVALID_NUMBER`` - illegal vector number -``RTEMS.INVALID_ADDRESS`` - illegal ISR entry point or invalid ``old_isr_handler`` - -**DESCRIPTION:** - -This directive establishes an interrupt service -routine (ISR) for the specified interrupt vector number. The``new_isr_handler`` parameter specifies the entry point of the ISR. -The entry point of the previous ISR for the specified vector is -returned in ``old_isr_handler``. - -To release an interrupt vector, pass the old handler’s address obtained -when the vector was first capture. - -**NOTES:** - -This directive will not cause the calling task to be preempted. - -INTERRUPT_DISABLE - Disable Interrupts --------------------------------------- -.. index:: disable interrupts - -**CALLING SEQUENCE:** - -.. code:: c - - function Interrupt_Disable return RTEMS.ISR_Level; - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -This directive disables all maskable interrupts and returns -the previous ``level``. A later invocation of the``rtems.interrupt_enable`` directive should be used to -restore the interrupt level. - -**NOTES:** - -This directive will not cause the calling task to be preempted. - -This directive is only available on uni-processor configurations. The -directive ``rtems.interrupt_local_disable`` is available on all -configurations. - -INTERRUPT_ENABLE - Enable Interrupts ------------------------------------- -.. index:: enable interrupts - -**CALLING SEQUENCE:** - -.. code:: c - - procedure Interrupt_Enable ( - Level : in RTEMS.ISR_Level - ); - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -This directive enables maskable interrupts to the ``level`` -which was returned by a previous call to``rtems.interrupt_disable``. -Immediately prior to invoking this directive, maskable interrupts should -be disabled by a call to ``rtems.interrupt_disable`` -and will be enabled when this directive returns to the caller. - -**NOTES:** - -This directive will not cause the calling task to be preempted. - -This directive is only available on uni-processor configurations. The -directive ``rtems.interrupt_local_enable`` is available on all -configurations. - -INTERRUPT_FLASH - Flash Interrupts ----------------------------------- -.. index:: flash interrupts - -**CALLING SEQUENCE:** - -.. code:: c - - procedure Interrupt_Flash ( - Level : in RTEMS.ISR_Level - ); - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -This directive temporarily enables maskable interrupts to the ``level`` -which was returned by a previous call to``rtems.interrupt_disable``. -Immediately prior to invoking this directive, maskable interrupts should -be disabled by a call to ``rtems.interrupt_disable`` -and will be redisabled when this directive returns to the caller. - -**NOTES:** - -This directive will not cause the calling task to be preempted. - -This directive is only available on uni-processor configurations. The -directives ``rtems.interrupt_local_disable`` and``rtems.interrupt_local_enable`` is available on all -configurations. - -INTERRUPT_LOCAL_DISABLE - Disable Interrupts on Current Processor ------------------------------------------------------------------ -.. index:: disable interrupts - -**CALLING SEQUENCE:** - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -This directive disables all maskable interrupts and returns -the previous ``level``. A later invocation of the``rtems.interrupt_local_enable`` directive should be used to -restore the interrupt level. - -**NOTES:** - -This directive will not cause the calling task to be preempted. - -On SMP configurations this will not ensure system wide mutual exclusion. Use -interrupt locks instead. - -INTERRUPT_LOCAL_ENABLE - Enable Interrupts on Current Processor ---------------------------------------------------------------- -.. index:: enable interrupts - -**CALLING SEQUENCE:** - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -This directive enables maskable interrupts to the ``level`` -which was returned by a previous call to``rtems.interrupt_local_disable``. -Immediately prior to invoking this directive, maskable interrupts should -be disabled by a call to ``rtems.interrupt_local_disable`` -and will be enabled when this directive returns to the caller. - -**NOTES:** - -This directive will not cause the calling task to be preempted. - -INTERRUPT_LOCK_INITIALIZE - Initialize an ISR Lock --------------------------------------------------- - -**CALLING SEQUENCE:** - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -Initializes an interrupt lock. - -**NOTES:** - -Concurrent initialization leads to unpredictable results. - -INTERRUPT_LOCK_ACQUIRE - Acquire an ISR Lock --------------------------------------------- - -**CALLING SEQUENCE:** - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -Interrupts will be disabled. On SMP configurations this directive acquires a -SMP lock. - -**NOTES:** - -This directive will not cause the calling thread to be preempted. This -directive can be used in thread and interrupt context. - -INTERRUPT_LOCK_RELEASE - Release an ISR Lock --------------------------------------------- - -**CALLING SEQUENCE:** - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -The interrupt status will be restored. On SMP configurations this directive -releases a SMP lock. - -**NOTES:** - -This directive will not cause the calling thread to be preempted. This -directive can be used in thread and interrupt context. - -INTERRUPT_LOCK_ACQUIRE_ISR - Acquire an ISR Lock from ISR ---------------------------------------------------------- - -**CALLING SEQUENCE:** - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -The interrupt status will remain unchanged. On SMP configurations this -directive acquires a SMP lock. - -In case the corresponding interrupt service routine can be interrupted by -higher priority interrupts and these interrupts enter the critical section -protected by this lock, then the result is unpredictable. - -**NOTES:** - -This directive should be called from the corresponding interrupt service -routine. - -INTERRUPT_LOCK_RELEASE_ISR - Release an ISR Lock from ISR ---------------------------------------------------------- - -**CALLING SEQUENCE:** - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -The interrupt status will remain unchanged. On SMP configurations this -directive releases a SMP lock. - -**NOTES:** - -This directive should be called from the corresponding interrupt service -routine. - -INTERRUPT_IS_IN_PROGRESS - Is an ISR in Progress ------------------------------------------------- -.. index:: is interrupt in progress - -**CALLING SEQUENCE:** - -.. code:: c - - function Interrupt_Is_In_Progress return RTEMS.Boolean; - -**DIRECTIVE STATUS CODES:** - -NONE - -**DESCRIPTION:** - -This directive returns ``TRUE`` if the processor is currently -servicing an interrupt and ``FALSE`` otherwise. A return value -of ``TRUE`` indicates that the caller is an interrupt service -routine, *NOT* a task. The directives available to an interrupt -service routine are restricted. - -**NOTES:** - -This directive will not cause the calling task to be preempted. - -.. COMMENT: COPYRIGHT (c) 1988-2008 - -.. COMMENT: On-Line Applications Research Corporation (OAR). - -.. COMMENT: All rights reserved. - |