26.21. BSP Related Configuration Options¶
This section describes configuration options related to the BSP. Some
configuration options may have a BSP-specific setting which is defined by
<bsp.h>
. The BSP-specific settings can be disabled by the
CONFIGURE_DISABLE_BSP_SETTINGS configuration option.
26.21.1. BSP_IDLE_TASK_BODY¶
CONSTANT:
BSP_IDLE_TASK_BODY
OPTION TYPE:
This configuration option is an initializer define.
DEFAULT VALUE:
The default value is BSP-specific.
DESCRIPTION:
If
this configuration option is defined by the BSP
and CONFIGURE_DISABLE_BSP_SETTINGS is undefined,
then the value of this configuration option defines the default value of CONFIGURE_IDLE_TASK_BODY.
NOTES:
As it has knowledge of the specific CPU model, system controller logic, and peripheral buses, a BSP-specific IDLE task may be capable of turning components off to save power during extended periods of no task activity.
CONSTRAINTS:
The value of the configuration option shall be defined to a valid function
pointer of the type void *( *idle_body )( uintptr_t )
.
26.21.2. BSP_IDLE_TASK_STACK_SIZE¶
CONSTANT:
BSP_IDLE_TASK_STACK_SIZE
OPTION TYPE:
This configuration option is an integer define.
DEFAULT VALUE:
The default value is BSP-specific.
DESCRIPTION:
If
this configuration option is defined by the BSP
and CONFIGURE_DISABLE_BSP_SETTINGS is undefined,
then the value of this configuration option defines the default value of CONFIGURE_IDLE_TASK_STACK_SIZE.
CONSTRAINTS:
The following constraints apply to this configuration option:
The value of the configuration option shall be greater than or equal to a BSP-specific and application-specific minimum value.
The value of the configuration option shall be small enough so that the IDLE task stack area calculation carried out by
<rtems/confdefs.h>
does not overflow an integer of type size_t.
26.21.3. BSP_INITIAL_EXTENSION¶
CONSTANT:
BSP_INITIAL_EXTENSION
OPTION TYPE:
This configuration option is an initializer define.
DEFAULT VALUE:
The default value is BSP-specific.
DESCRIPTION:
If
this configuration option is defined by the BSP
and CONFIGURE_DISABLE_BSP_SETTINGS is undefined,
then the value of this configuration option is used to initialize the table of initial user extensions.
NOTES:
The value of this configuration option is placed after the entries of all other initial user extensions.
CONSTRAINTS:
The value of the configuration option shall be a list of initializers for
structures of type rtems_extensions_table
.
26.21.4. BSP_INTERRUPT_STACK_SIZE¶
CONSTANT:
BSP_INTERRUPT_STACK_SIZE
OPTION TYPE:
This configuration option is an integer define.
DEFAULT VALUE:
The default value is BSP-specific.
DESCRIPTION:
If
this configuration option is defined by the BSP
and CONFIGURE_DISABLE_BSP_SETTINGS is undefined,
then the value of this configuration option defines the default value of CONFIGURE_INTERRUPT_STACK_SIZE.
CONSTRAINTS:
The following constraints apply to this configuration option:
The value of the configuration option shall be greater than or equal to a BSP-specific and application-specific minimum value.
The value of the configuration option shall be small enough so that the interrupt stack area calculation carried out by
<rtems/confdefs.h>
does not overflow an integer of type size_t.The value of the configuration option shall be aligned according to
CPU_INTERRUPT_STACK_ALIGNMENT
.
26.21.5. CONFIGURE_BSP_PREREQUISITE_DRIVERS¶
CONSTANT:
CONFIGURE_BSP_PREREQUISITE_DRIVERS
OPTION TYPE:
This configuration option is an initializer define.
DEFAULT VALUE:
The default value is BSP-specific.
DESCRIPTION:
If
this configuration option is defined by the BSP
and CONFIGURE_DISABLE_BSP_SETTINGS is undefined,
then the value of this configuration option is used to add BSP-provided prerequisite drivers to the Device Driver Table.
NOTES:
The value of this configuration option is placed before the entries of all other initial user extensions (including CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS).
CONSTRAINTS:
The value of the configuration option shall be a list of initializers for
structures of type rtems_extensions_table
.
26.21.6. CONFIGURE_DISABLE_BSP_SETTINGS¶
CONSTANT:
CONFIGURE_DISABLE_BSP_SETTINGS
OPTION TYPE:
This configuration option is a boolean feature define.
DEFAULT CONFIGURATION:
If this configuration option is undefined, then the described feature is not enabled.
DESCRIPTION:
In case this configuration option is defined, then the following BSP related configuration options are undefined:
26.21.7. CONFIGURE_MALLOC_BSP_SUPPORTS_SBRK¶
CONSTANT:
CONFIGURE_MALLOC_BSP_SUPPORTS_SBRK
OPTION TYPE:
This configuration option is a boolean feature define.
DEFAULT CONFIGURATION:
If this configuration option is undefined, then the described feature is not enabled.
DESCRIPTION:
If
this configuration option is defined by the BSP
and CONFIGURE_DISABLE_BSP_SETTINGS is undefined,
then not all memory is made available to the C Program Heap immediately at
system initialization time. When malloc()
or other standard
memory allocation functions are unable to allocate memory, they will call the
BSP supplied sbrk()
function to obtain more memory.
NOTES:
This option should not be defined by the application. Only the BSP knows how it allocates memory to the C Program Heap.