[PATCH] eng: Add register block specification types

Sat Sep 11 17:59:01 UTC 2021

On Fri, Sep 10, 2021, 9:41 AM Sebastian Huber <
sebastian.huber at embedded-brains.de> wrote:

> A register block may be used to specify the memory-mapped interface to
> the hardware.  Register blocks consist of register block members.
> Register block members are either instances of registers or instances of
> other register blocks.  Registers consists of bit fields.
>

I hope you don't mean C bit fields. They are quite non-portable.

And I hope we are avoiding packed in this definition of requirements set.

Unfortunately it seems there are more things you can get wrong here which
leads to negative requirements and negative requirements are bad

>
> Update #3715.
> ---
> For examples see:
>
> https://git.rtems.org/rtems-central/tree/spec/dev/grlib/if
>
>  eng/req/items.rst | 334 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 334 insertions(+)
>
> diff --git a/eng/req/items.rst b/eng/req/items.rst
> index 1489f19..be6ab5f 100644
> --- a/eng/req/items.rst
> +++ b/eng/req/items.rst
> @@ -103,6 +103,8 @@ The specification item types have the following
> hierarchy:
>
>      * :ref:`SpecTypeInterfaceVariableItemType`
>
> +    * :ref:`SpecTypeRegisterBlockItemType`
> +
>    * :ref:`SpecTypeRequirementItemType`
>
>      * :ref:`SpecTypeFunctionalRequirementItemType`
> @@ -1143,6 +1145,8 @@ This type is refined by the following types:
>
>  * :ref:`SpecTypeInterfaceVariableItemType`
>
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
>  .. _SpecTypeApplicationConfigurationGroupItemType:
>
>  Application Configuration Group Item Type
> @@ -1614,6 +1618,67 @@ name
>  notes
>      The attribute value shall be an :ref:`SpecTypeInterfaceNotes`.
>
> +.. _SpecTypeRegisterBlockItemType:
> +
> +Register Block Item Type
> +^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +This type refines the :ref:`SpecTypeInterfaceItemType` through the
> +``interface-type`` attribute if the value is ``register-block``. This set
> of
> +attributes specifies a register block.  A register block may be used to
> specify
> +the memory-mapped interface to the hardware.  Register blocks consist of
> +register block members specified by the ``definition`` attribute.
> Register
> +block members are either instances of registers specified by the
> ``registers``
> +attribute or instances of other register blocks specified by links with
> the
> +:ref:`SpecTypeRegisterBlockIncludeRole`.  Registers consists of bit
> fields (see
> +:ref:`SpecTypeRegisterBitsDefinition`. All explicit attributes shall be
> +specified. The explicit attributes for this type are:
> +
> +brief
> +    The attribute value shall be an
> :ref:`SpecTypeInterfaceBriefDescription`.
> +
> +definition
> +    The attribute value shall be a list. Each list element shall be a
> +    :ref:`SpecTypeRegisterBlockMemberDefinitionDirective`.
> +
> +description
> +    The attribute value shall be an :ref:`SpecTypeInterfaceDescription`.
> +
> +identifier
> +    The attribute value shall be an
> :ref:`SpecTypeInterfaceGroupIdentifier`.
> +
> +name
> +    The attribute value shall be a string. It shall be the name of the
> register
> +    block.
> +
> +notes
> +    The attribute value shall be an :ref:`SpecTypeInterfaceNotes`.
> +
> +register-block-group
> +    The attribute value shall be a string. It shall be the name of the
> +    interface group defined for the register block.  For the group
> identifier
> +    see the ``identifier`` attribute.
> +
> +register-block-size
> +    The attribute value shall be an integer number. It shall be the size
> in
> +    bytes of the register block.
> +
> +register-block-type
> +    The attribute value shall be a :ref:`SpecTypeRegisterBlockType`.
> +
> +register-prefix
> +    The attribute value shall be an optional string. If the value is
> present,
> +    then it will be used to prefix register bit field names, otherwise the
> +    value of the ``name`` attribute will be used.
> +
> +registers
> +    The attribute value shall be a list. Each list element shall be a
> +    :ref:`SpecTypeRegisterDefinition`.
> +
> +In addition to the explicit attributes, generic attributes may be
> specified.
> +Each generic attribute key shall be a :ref:`SpecTypeName`. The attribute
> value
> +may have any type.
> +
>  .. _SpecTypeRequirementItemType:
>
>  Requirement Item Type
> @@ -3733,6 +3798,12 @@ This type is used by the following types:
>
>  * :ref:`SpecTypeInterfaceVariableItemType`
>
> +* :ref:`SpecTypeRegisterBitsDefinition`
> +
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
> +* :ref:`SpecTypeRegisterDefinition`
> +
>  .. _SpecTypeInterfaceCompoundDefinitionKind:
>
>  Interface Compound Definition Kind
> @@ -3992,6 +4063,12 @@ This type is used by the following types:
>
>  * :ref:`SpecTypeInterfaceVariableItemType`
>
> +* :ref:`SpecTypeRegisterBitsDefinition`
> +
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
> +* :ref:`SpecTypeRegisterDefinition`
> +
>  .. _SpecTypeInterfaceEnabledByExpression:
>
>  Interface Enabled-By Expression
> @@ -4041,6 +4118,10 @@ This type is used by the following types:
>
>  * :ref:`SpecTypeInterfaceFunctionDefinitionVariant`
>
> +* :ref:`SpecTypeRegisterBitsDefinitionVariant`
> +
> +* :ref:`SpecTypeRegisterBlockMemberDefinitionVariant`
> +
>  .. _SpecTypeInterfaceEnumDefinitionKind:
>
>  Interface Enum Definition Kind
> @@ -4182,6 +4263,8 @@ This type is used by the following types:
>
>  * :ref:`SpecTypeInterfaceGroupItemType`
>
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
>  .. _SpecTypeInterfaceGroupMembershipLinkRole:
>
>  Interface Group Membership Link Role
> @@ -4248,6 +4331,8 @@ This type is used by the following types:
>
>  * :ref:`SpecTypeInterfaceVariableItemType`
>
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
>  .. _SpecTypeInterfaceParameter:
>
>  Interface Parameter
> @@ -4423,6 +4508,8 @@ This type is refined by the following types:
>
>  * :ref:`SpecTypePlacementOrderLinkRole`
>
> +* :ref:`SpecTypeRegisterBlockIncludeRole`
> +
>  * :ref:`SpecTypeRequirementRefinementLinkRole`
>
>  * :ref:`SpecTypeRequirementValidationLinkRole`
> @@ -4471,6 +4558,10 @@ This type is used by the following types:
>
>  * :ref:`SpecTypeNonFunctionalRequirementItemType`
>
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
> +* :ref:`SpecTypeRegisterDefinition`
> +
>  * :ref:`SpecTypeRequirementItemType`
>
>  * :ref:`SpecTypeRootItemType`
> @@ -4512,6 +4603,249 @@ value is ``placement-order``. This link role
> defines the placement order of
>  items in a container item (for example an interface function in a header
> file
>  or a documentation section).
>
> +.. _SpecTypeRegisterBitsDefinition:
> +
> +Register Bits Definition
> +^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +A value of this type shall be of one of the following variants:
> +
> +* The value may be a set of attributes. This set of attributes specifies
> +  register bits. All explicit attributes shall be specified. The explicit
> +  attributes for this type are:
> +
> +  access
> +      The attribute value shall be a list of strings. It shall be the
> list of
> +      access attributes.
> +
> +  brief
> +      The attribute value shall be an
> :ref:`SpecTypeInterfaceBriefDescription`.
> +
> +  description
> +      The attribute value shall be an :ref:`SpecTypeInterfaceDescription`.
> +
> +  name
> +      The attribute value shall be a string. It shall be the name of the
> +      register bit field.
> +
> +  start
> +      The attribute value shall be an integer number. It shall be the
> start bit
> +      of the bit field.
> +
> +  width
> +      The attribute value shall be an integer number. It shall be the
> width in
> +      bits of the bit field.
> +
> +* There may by be no value (null).
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBitsDefinitionDirective`
> +
> +* :ref:`SpecTypeRegisterBitsDefinitionVariant`
> +
> +.. _SpecTypeRegisterBitsDefinitionDirective:
> +
> +Register Bits Definition Directive
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +This set of attributes specifies a register bits directive. All explicit
> +attributes shall be specified. The explicit attributes for this type are:
> +
> +default
> +    The attribute value shall be a list. Each list element shall be a
> +    :ref:`SpecTypeRegisterBitsDefinition`. The default definition will be
> used
> +    if no variant-specific definition is enabled.
> +
> +variants
> +    The attribute value shall be a list. Each list element shall be a
> +    :ref:`SpecTypeRegisterBitsDefinitionVariant`.
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterDefinition`
> +
> +.. _SpecTypeRegisterBitsDefinitionVariant:
> +
> +Register Bits Definition Variant
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +This set of attributes specifies a register bits variant. All explicit
> +attributes shall be specified. The explicit attributes for this type are:
> +
> +definition
> +    The attribute value shall be a list. Each list element shall be a
> +    :ref:`SpecTypeRegisterBitsDefinition`. The definition will be used if
> the
> +    expression defined by the ``enabled-by`` attribute evaluates to
> true.  In
> +    generated header files, the expression is evaluated by the C
> preprocessor.
> +
> +enabled-by
> +    The attribute value shall be an
> +    :ref:`SpecTypeInterfaceEnabledByExpression`.
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBitsDefinitionDirective`
> +
> +.. _SpecTypeRegisterBlockIncludeRole:
> +
> +Register Block Include Role
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +This type refines the :ref:`SpecTypeLink` through the ``role`` attribute
> if the
> +value is ``register-block-include``. It defines the register block
> include role
> +of links.  Links of this role are used to build register blocks using
> other
> +register blocks. All explicit attributes shall be specified. The explicit
> +attributes for this type are:
> +
> +name
> +    The attribute value shall be a string. It shall be the unique name to
> +    identify the included register block within the item.
> +
> +.. _SpecTypeRegisterBlockMemberDefinition:
> +
> +Register Block Member Definition
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +A value of this type shall be of one of the following variants:
> +
> +* The value may be a set of attributes. This set of attributes specifies a
> +  register block member definition. All explicit attributes shall be
> specified.
> +  The explicit attributes for this type are:
> +
> +  count
> +      The attribute value shall be an integer number. It shall be the
> count of
> +      registers of the register block member.
> +
> +  name
> +      The attribute value shall be a :ref:`SpecTypeRegisterName`.
> +
> +* There may by be no value (null).
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBlockMemberDefinitionDirective`
> +
> +* :ref:`SpecTypeRegisterBlockMemberDefinitionVariant`
> +
> +.. _SpecTypeRegisterBlockMemberDefinitionDirective:
> +
> +Register Block Member Definition Directive
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +This set of attributes specifies a register block member definition
> directive.
> +All explicit attributes shall be specified. The explicit attributes for
> this
> +type are:
> +
> +default
> +    The attribute value shall be a
> +    :ref:`SpecTypeRegisterBlockMemberDefinition`. The default definition
> will
> +    be used if no variant-specific definition is enabled.
> +
> +offset
> +    The attribute value shall be an integer number. It shall be the
> offset in
> +    bytes from the register block begin to the register member.
> +
> +variants
> +    The attribute value shall be a list. Each list element shall be a
> +    :ref:`SpecTypeRegisterBlockMemberDefinitionVariant`.
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
> +.. _SpecTypeRegisterBlockMemberDefinitionVariant:
> +
> +Register Block Member Definition Variant
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +This set of attributes specifies a register block member definition
> variant.
> +All explicit attributes shall be specified. The explicit attributes for
> this
> +type are:
> +
> +definition
> +    The attribute value shall be a
> +    :ref:`SpecTypeRegisterBlockMemberDefinition`. The definition will be
> used
> +    if the expression defined by the ``enabled-by`` attribute evaluates to
> +    true.  In generated header files, the expression is evaluated by the C
> +    preprocessor.
> +
> +enabled-by
> +    The attribute value shall be an
> +    :ref:`SpecTypeInterfaceEnabledByExpression`.
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBlockMemberDefinitionDirective`
> +
> +.. _SpecTypeRegisterBlockType:
> +
> +Register Block Type
> +^^^^^^^^^^^^^^^^^^^
> +
> +The value shall be a string. It specifies the register block type. The
> value
> +shall be an element of
> +
> +* "``memory``".
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
> +.. _SpecTypeRegisterDefinition:
> +
> +Register Definition
> +^^^^^^^^^^^^^^^^^^^
> +
> +This set of attributes specifies a register. All explicit attributes
> shall be
> +specified. The explicit attributes for this type are:
> +
> +bits
> +    The attribute value shall be a list. Each list element shall be a
> +    :ref:`SpecTypeRegisterBitsDefinitionDirective`.
> +
> +brief
> +    The attribute value shall be an
> :ref:`SpecTypeInterfaceBriefDescription`.
> +
> +description
> +    The attribute value shall be an :ref:`SpecTypeInterfaceDescription`.
> +
> +name
> +    The attribute value shall be a string. It shall be the unique name to
> +    identify the register definition.
> +
> +width
> +    The attribute value shall be an integer number. It shall be the width
> of
> +    the register in bits.
> +
> +In addition to the explicit attributes, generic attributes may be
> specified.
> +Each generic attribute key shall be a :ref:`SpecTypeName`. The attribute
> value
> +may have any type.
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBlockItemType`
> +
> +.. _SpecTypeRegisterName:
> +
> +Register Name
> +^^^^^^^^^^^^^
> +
> +The value shall be a string. The name consists either of an identifier,
> or an
> +identifier and an alias. The identifier and alias are separated by a colon
> +(``:``).  The identifier shall match with the name of a register
> definition of
> +the item (see :ref:`SpecTypeRegisterDefinition`) or the name of a register
> +block include of the item (see :ref:`SpecTypeRegisterBlockIncludeRole`).
> If no
> +alias is specified, then the identifier is used for the register block
> member
> +name, otherwise the alias is used.  If the register block member names
> are not
> +unique within the item, then a postfix number is appended to the names.
> The
> +number starts with zero for each set of names. The value shall match with
> the
> +regular expression
> "``^[a-zA-Z_][a-zA-Z0-9_]*(:[a-zA-Z_][a-zA-Z0-9_]*)?$``".
> +
> +This type is used by the following types:
> +
> +* :ref:`SpecTypeRegisterBlockMemberDefinition`
> +
>  .. _SpecTypeRequirementReference:
>
>  Requirement Reference
> --
> 2.31.1
>
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