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Diffstat (limited to 'c-user/partition')
| -rw-r--r-- | c-user/partition/background.rst | 50 | ||||
| -rw-r--r-- | c-user/partition/directives.rst | 535 | ||||
| -rw-r--r-- | c-user/partition/index.rst | 17 | ||||
| -rw-r--r-- | c-user/partition/introduction.rst | 49 | ||||
| -rw-r--r-- | c-user/partition/operations.rst | 55 |
5 files changed, 706 insertions, 0 deletions
diff --git a/c-user/partition/background.rst b/c-user/partition/background.rst new file mode 100644 index 0000000..ce38fc7 --- /dev/null +++ b/c-user/partition/background.rst @@ -0,0 +1,50 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) + +Background +========== + +.. index:: partition, definition + +Partition Manager Definitions +----------------------------- + +A partition is a physically contiguous memory area divided into fixed-size +buffers that can be dynamically allocated and deallocated. + +.. index:: buffers, definition + +Partitions are managed and maintained as a list of buffers. Buffers are +obtained from the front of the partition's free buffer chain and returned to +the rear of the same chain. When a buffer is on the free buffer chain, RTEMS +uses two pointers of memory from each buffer as the free buffer chain. When a +buffer is allocated, the entire buffer is available for application use. +Therefore, modifying memory that is outside of an allocated buffer could +destroy the free buffer chain or the contents of an adjacent allocated buffer. + +.. index:: partition attribute set, building + +Building a Partition Attribute Set +---------------------------------- + +In general, an attribute set is built by a bitwise OR of the desired attribute +components. The set of valid partition attributes is provided in the following +table: + +.. list-table:: + :class: rtems-table + + * - ``RTEMS_LOCAL`` + - local partition (default) + * - ``RTEMS_GLOBAL`` + - global partition + +Attribute values are specifically designed to be mutually exclusive, therefore +bitwise OR and addition operations are equivalent as long as each attribute +appears exactly once in the component list. An attribute listed as a default +is not required to appear in the attribute list, although it is a good +programming practice to specify default attributes. If all defaults are +desired, the attribute ``RTEMS_DEFAULT_ATTRIBUTES`` should be specified on this +call. The attribute_set parameter should be ``RTEMS_GLOBAL`` to indicate that +the partition is to be known globally. diff --git a/c-user/partition/directives.rst b/c-user/partition/directives.rst new file mode 100644 index 0000000..da5983c --- /dev/null +++ b/c-user/partition/directives.rst @@ -0,0 +1,535 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. Copyright (C) 2020, 2021 embedded brains GmbH & Co. KG +.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) + +.. This file is part of the RTEMS quality process and was automatically +.. generated. If you find something that needs to be fixed or +.. worded better please post a report or patch to an RTEMS mailing list +.. or raise a bug report: +.. +.. https://www.rtems.org/bugs.html +.. +.. For information on updating and regenerating please refer to the How-To +.. section in the Software Requirements Engineering chapter of the +.. RTEMS Software Engineering manual. The manual is provided as a part of +.. a release. For development sources please refer to the online +.. documentation at: +.. +.. https://docs.rtems.org + +.. _PartitionManagerDirectives: + +Directives +========== + +This section details the directives of the Partition Manager. A subsection is +dedicated to each of this manager's directives and lists the calling sequence, +parameters, description, return values, and notes of the directive. + +.. Generated from spec:/rtems/part/if/create + +.. raw:: latex + + \clearpage + +.. index:: rtems_partition_create() +.. index:: create a partition + +.. _InterfaceRtemsPartitionCreate: + +rtems_partition_create() +------------------------ + +Creates a partition. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_partition_create( + rtems_name name, + void *starting_address, + uintptr_t length, + size_t buffer_size, + rtems_attribute attribute_set, + rtems_id *id + ); + +.. rubric:: PARAMETERS: + +``name`` + This parameter is the object name of the partition. + +``starting_address`` + This parameter is the starting address of the buffer area used by the + partition. + +``length`` + This parameter is the length in bytes of the buffer area used by the + partition. + +``buffer_size`` + This parameter is the size in bytes of a buffer managed by the partition. + +``attribute_set`` + This parameter is the attribute set of the partition. + +``id`` + This parameter is the pointer to an :ref:`InterfaceRtemsId` object. When + the directive call is successful, the identifier of the created partition + will be stored in this object. + +.. rubric:: DESCRIPTION: + +This directive creates a partition of fixed size buffers from a physically +contiguous memory space which starts at ``starting_address`` and is ``length`` +bytes in size. Each allocated buffer is to be of ``buffer_size`` in bytes. +The partition has the user-defined object name specified in ``name``. The +assigned object identifier is returned in ``id``. This identifier is used to +access the partition with other partition related directives. + +The **attribute set** specified in ``attribute_set`` is built through a +*bitwise or* of the attribute constants described below. Not all combinations +of attributes are allowed. Some attributes are mutually exclusive. If +mutually exclusive attributes are combined, the behaviour is undefined. +Attributes not mentioned below are not evaluated by this directive and have no +effect. Default attributes can be selected by using the +:c:macro:`RTEMS_DEFAULT_ATTRIBUTES` constant. + +The partition has a local or global **scope** in a multiprocessing network +(this attribute does not refer to SMP systems). The scope is selected by the +mutually exclusive :c:macro:`RTEMS_LOCAL` and :c:macro:`RTEMS_GLOBAL` +attributes. + +* A **local scope** is the default and can be emphasized through the use of the + :c:macro:`RTEMS_LOCAL` attribute. A local partition can be only used by the + node which created it. + +* A **global scope** is established if the :c:macro:`RTEMS_GLOBAL` attribute is + set. The memory space used for the partition must reside in shared memory. + Setting the global attribute in a single node system has no effect. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_NAME` + The ``name`` parameter was invalid. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``id`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. + +:c:macro:`RTEMS_INVALID_SIZE` + The ``length`` parameter was 0. + +:c:macro:`RTEMS_INVALID_SIZE` + The ``buffer_size`` parameter was 0. + +:c:macro:`RTEMS_INVALID_SIZE` + The ``length`` parameter was less than the ``buffer_size`` parameter. + +:c:macro:`RTEMS_INVALID_SIZE` + The ``buffer_size`` parameter was not an integral multiple of the pointer + size. + +:c:macro:`RTEMS_INVALID_SIZE` + The ``buffer_size`` parameter was less than two times the pointer size. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``starting_address`` parameter was not on a pointer size boundary. + +:c:macro:`RTEMS_TOO_MANY` + There was no inactive object available to create a partition. The number + of partitions available to the application is configured through the + :ref:`CONFIGURE_MAXIMUM_PARTITIONS` application configuration option. + +:c:macro:`RTEMS_TOO_MANY` + In multiprocessing configurations, there was no inactive global object + available to create a global semaphore. The number of global objects + available to the application is configured through the + :ref:`CONFIGURE_MP_MAXIMUM_GLOBAL_OBJECTS` application configuration + option. + +.. rubric:: NOTES: + +The partition buffer area specified by the ``starting_address`` must be +properly aligned. It must be possible to directly store target architecture +pointers and also the user data. For example, if the user data contains some +long double or vector data types, the partition buffer area and the buffer size +must take the alignment of these types into account which is usually larger +than the pointer alignment. A cache line alignment may be also a factor. Use +:c:macro:`RTEMS_PARTITION_ALIGNMENT` to specify the minimum alignment of a +partition buffer type. + +The ``buffer_size`` parameter must be an integral multiple of the pointer size +on the target architecture. Additionally, ``buffer_size`` must be large enough +to hold two pointers on the target architecture. This is required for RTEMS to +manage the buffers when they are free. + +For control and maintenance of the partition, RTEMS allocates a :term:`PTCB` +from the local PTCB free pool and initializes it. Memory from the partition +buffer area is not used by RTEMS to store the PTCB. + +The PTCB for a global partition is allocated on the local node. Partitions +should not be made global unless remote tasks must interact with the partition. +This is to avoid the overhead incurred by the creation of a global partition. +When a global partition is created, the partition's name and identifier must be +transmitted to every node in the system for insertion in the local copy of the +global object table. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within device driver initialization context. + +* The directive may be called from within task context. + +* The directive may obtain and release the object allocator mutex. This may + cause the calling task to be preempted. + +* When the directive operates on a global object, the directive sends a message + to remote nodes. This may preempt the calling task. + +* The number of partitions available to the application is configured through + the :ref:`CONFIGURE_MAXIMUM_PARTITIONS` application configuration option. + +* Where the object class corresponding to the directive is configured to use + unlimited objects, the directive may allocate memory from the RTEMS + Workspace. + +* The number of global objects available to the application is configured + through the :ref:`CONFIGURE_MP_MAXIMUM_GLOBAL_OBJECTS` application + configuration option. + +.. Generated from spec:/rtems/part/if/ident + +.. raw:: latex + + \clearpage + +.. index:: rtems_partition_ident() +.. index:: get ID of a partition +.. index:: obtain ID of a partition + +.. _InterfaceRtemsPartitionIdent: + +rtems_partition_ident() +----------------------- + +Identifies a partition by the object name. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_partition_ident( + rtems_name name, + uint32_t node, + rtems_id *id + ); + +.. rubric:: PARAMETERS: + +``name`` + This parameter is the object name to look up. + +``node`` + This parameter is the node or node set to search for a matching object. + +``id`` + This parameter is the pointer to an :ref:`InterfaceRtemsId` object. When + the directive call is successful, the object identifier of an object with + the specified name will be stored in this object. + +.. rubric:: DESCRIPTION: + +This directive obtains a partition identifier associated with the partition +name specified in ``name``. + +The node to search is specified in ``node``. It shall be + +* a valid node number, + +* the constant :c:macro:`RTEMS_SEARCH_ALL_NODES` to search in all nodes, + +* the constant :c:macro:`RTEMS_SEARCH_LOCAL_NODE` to search in the local node + only, or + +* the constant :c:macro:`RTEMS_SEARCH_OTHER_NODES` to search in all nodes + except the local node. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``id`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. + +:c:macro:`RTEMS_INVALID_NAME` + The ``name`` parameter was 0. + +:c:macro:`RTEMS_INVALID_NAME` + There was no object with the specified name on the specified nodes. + +:c:macro:`RTEMS_INVALID_NODE` + In multiprocessing configurations, the specified node was invalid. + +.. rubric:: NOTES: + +If the partition name is not unique, then the partition identifier will match +the first partition with that name in the search order. However, this +partition identifier is not guaranteed to correspond to the desired partition. + +The objects are searched from lowest to the highest index. If ``node`` is +:c:macro:`RTEMS_SEARCH_ALL_NODES`, all nodes are searched with the local node +being searched first. All other nodes are searched from lowest to the highest +node number. + +If node is a valid node number which does not represent the local node, then +only the partitions exported by the designated node are searched. + +This directive does not generate activity on remote nodes. It accesses only +the local copy of the global object table. + +The partition identifier is used with other partition related directives to +access the partition. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/part/if/delete + +.. raw:: latex + + \clearpage + +.. index:: rtems_partition_delete() +.. index:: delete a partition + +.. _InterfaceRtemsPartitionDelete: + +rtems_partition_delete() +------------------------ + +Deletes the partition. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_partition_delete( rtems_id id ); + +.. rubric:: PARAMETERS: + +``id`` + This parameter is the partition identifier. + +.. rubric:: DESCRIPTION: + +This directive deletes the partition specified by ``id``. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ID` + There was no partition associated with the identifier specified by ``id``. + +:c:macro:`RTEMS_ILLEGAL_ON_REMOTE_OBJECT` + The partition resided on a remote node. + +:c:macro:`RTEMS_RESOURCE_IN_USE` + There were buffers of the partition still in use. + +.. rubric:: NOTES: + +The partition cannot be deleted if any of its buffers are still allocated. + +The :term:`PTCB` for the deleted partition is reclaimed by RTEMS. + +When a global partition is deleted, the partition identifier must be +transmitted to every node in the system for deletion from the local copy of the +global object table. + +The partition must reside on the local node, even if the partition was created +with the :c:macro:`RTEMS_GLOBAL` attribute. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within device driver initialization context. + +* The directive may be called from within task context. + +* The directive may obtain and release the object allocator mutex. This may + cause the calling task to be preempted. + +* When the directive operates on a global object, the directive sends a message + to remote nodes. This may preempt the calling task. + +* The calling task does not have to be the task that created the object. Any + local task that knows the object identifier can delete the object. + +* Where the object class corresponding to the directive is configured to use + unlimited objects, the directive may free memory to the RTEMS Workspace. + +.. Generated from spec:/rtems/part/if/get-buffer + +.. raw:: latex + + \clearpage + +.. index:: rtems_partition_get_buffer() +.. index:: get buffer from partition +.. index:: obtain buffer from partition + +.. _InterfaceRtemsPartitionGetBuffer: + +rtems_partition_get_buffer() +---------------------------- + +Tries to get a buffer from the partition. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_partition_get_buffer( rtems_id id, void **buffer ); + +.. rubric:: PARAMETERS: + +``id`` + This parameter is the partition identifier. + +``buffer`` + This parameter is the pointer to a ``void`` pointer object. When the + directive call is successful, the pointer to the allocated buffer will be + stored in this object. + +.. rubric:: DESCRIPTION: + +This directive allows a buffer to be obtained from the partition specified by +``id``. The address of the allocated buffer is returned through the ``buffer`` +parameter. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ID` + There was no partition associated with the identifier specified by ``id``. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``buffer`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. + +:c:macro:`RTEMS_UNSATISFIED` + There was no free buffer available to allocate and return. + +.. rubric:: NOTES: + +The buffer start alignment is determined by the memory area and buffer size +used to create the partition. + +A task cannot wait on a buffer to become available. + +Getting a buffer from a global partition which does not reside on the local +node will generate a request telling the remote node to allocate a buffer from +the partition. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* When the directive operates on a local object, the directive may be called + from within interrupt context. + +* The directive may be called from within task context. + +* When the directive operates on a local object, the directive will not cause + the calling task to be preempted. + +* When the directive operates on a remote object, the directive sends a message + to the remote node and waits for a reply. This will preempt the calling + task. + +.. Generated from spec:/rtems/part/if/return-buffer + +.. raw:: latex + + \clearpage + +.. index:: rtems_partition_return_buffer() +.. index:: return buffer to partition + +.. _InterfaceRtemsPartitionReturnBuffer: + +rtems_partition_return_buffer() +------------------------------- + +Returns the buffer to the partition. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_partition_return_buffer( rtems_id id, void *buffer ); + +.. rubric:: PARAMETERS: + +``id`` + This parameter is the partition identifier. + +``buffer`` + This parameter is the pointer to the buffer to return. + +.. rubric:: DESCRIPTION: + +This directive returns the buffer specified by ``buffer`` to the partition +specified by ``id``. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ID` + There was no partition associated with the identifier specified by ``id``. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The buffer referenced by ``buffer`` was not in the partition. + +.. rubric:: NOTES: + +Returning a buffer multiple times is an error. It will corrupt the internal +state of the partition. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* When the directive operates on a local object, the directive may be called + from within interrupt context. + +* The directive may be called from within task context. + +* When the directive operates on a local object, the directive will not cause + the calling task to be preempted. + +* When the directive operates on a remote object, the directive sends a message + to the remote node and waits for a reply. This will preempt the calling + task. diff --git a/c-user/partition/index.rst b/c-user/partition/index.rst new file mode 100644 index 0000000..652fdfa --- /dev/null +++ b/c-user/partition/index.rst @@ -0,0 +1,17 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. Copyright (C) 2020 embedded brains GmbH & Co. KG + +.. index:: partitions + +.. _RTEMSAPIClassicPart: + +Partition Manager +***************** + +.. toctree:: + + introduction + background + operations + directives diff --git a/c-user/partition/introduction.rst b/c-user/partition/introduction.rst new file mode 100644 index 0000000..ca26de9 --- /dev/null +++ b/c-user/partition/introduction.rst @@ -0,0 +1,49 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. Copyright (C) 2020, 2021 embedded brains GmbH & Co. KG +.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) + +.. This file is part of the RTEMS quality process and was automatically +.. generated. If you find something that needs to be fixed or +.. worded better please post a report or patch to an RTEMS mailing list +.. or raise a bug report: +.. +.. https://www.rtems.org/bugs.html +.. +.. For information on updating and regenerating please refer to the How-To +.. section in the Software Requirements Engineering chapter of the +.. RTEMS Software Engineering manual. The manual is provided as a part of +.. a release. For development sources please refer to the online +.. documentation at: +.. +.. https://docs.rtems.org + +.. Generated from spec:/rtems/part/if/group + +.. _PartitionManagerIntroduction: + +Introduction +============ + +.. The following list was generated from: +.. spec:/rtems/part/if/create +.. spec:/rtems/part/if/ident +.. spec:/rtems/part/if/delete +.. spec:/rtems/part/if/get-buffer +.. spec:/rtems/part/if/return-buffer + +The Partition Manager provides facilities to dynamically allocate memory in +fixed-size units. The directives provided by the Partition Manager are: + +* :ref:`InterfaceRtemsPartitionCreate` - Creates a partition. + +* :ref:`InterfaceRtemsPartitionIdent` - Identifies a partition by the object + name. + +* :ref:`InterfaceRtemsPartitionDelete` - Deletes the partition. + +* :ref:`InterfaceRtemsPartitionGetBuffer` - Tries to get a buffer from the + partition. + +* :ref:`InterfaceRtemsPartitionReturnBuffer` - Returns the buffer to the + partition. diff --git a/c-user/partition/operations.rst b/c-user/partition/operations.rst new file mode 100644 index 0000000..d0eff5b --- /dev/null +++ b/c-user/partition/operations.rst @@ -0,0 +1,55 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) + +Operations +========== + +Creating a Partition +-------------------- + +The ``rtems_partition_create`` directive creates a partition with a +user-specified name. The partition's name, starting address, length and buffer +size are all specified to the ``rtems_partition_create`` directive. RTEMS +allocates a Partition Control Block (PTCB) from the PTCB free list. This data +structure is used by RTEMS to manage the newly created partition. The number +of buffers in the partition is calculated based upon the specified partition +length and buffer size. If successful,the unique partition ID is returned to +the calling task. + +Obtaining Partition IDs +----------------------- + +When a partition is created, RTEMS generates a unique partition ID and assigned +it to the created partition until it is deleted. The partition ID may be +obtained by either of two methods. First, as the result of an invocation of +the ``rtems_partition_create`` directive, the partition ID is stored in a user +provided location. Second, the partition ID may be obtained later using the +``rtems_partition_ident`` directive. The partition ID is used by other +partition manager directives to access this partition. + +Acquiring a Buffer +------------------ + +A buffer can be obtained by calling the ``rtems_partition_get_buffer`` +directive. If a buffer is available, then it is returned immediately with a +successful return code. Otherwise, an unsuccessful return code is returned +immediately to the caller. Tasks cannot block to wait for a buffer to become +available. + +Releasing a Buffer +------------------ + +Buffers are returned to a partition's free buffer chain with the +``rtems_partition_return_buffer`` directive. This directive returns an error +status code if the returned buffer was not previously allocated from this +partition. + +Deleting a Partition +-------------------- + +The ``rtems_partition_delete`` directive allows a partition to be removed and +returned to RTEMS. When a partition is deleted, the PTCB for that partition is +returned to the PTCB free list. A partition with buffers still allocated +cannot be deleted. Any task attempting to do so will be returned an error +status code. |