.. SPDX-License-Identifier: CC-BY-SA-4.0 .. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) Device Driver Configuration =========================== This section describes configuration options related to the device drivers. Note that network device drivers are not covered by the following options. .. index:: CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER .. _CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER: CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER ------------------------------------------------ CONSTANT: ``CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`` OPTION TYPE: This configuration option is a boolean feature define. DEFAULT CONFIGURATION: If this configuration option is undefined, then a Clock Driver may be initialized during system initialization. DESCRIPTION: In case this configuration option is defined, then **no** Clock Driver is initialized during system initialization. NOTES: This configuration parameter is intended to prevent the common user error of using the Hello World example as the baseline for an application and leaving out a clock tick source. The application must define exactly one of the following configuration options * :ref:`CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER`, * `CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`, or * :ref:`CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER`, otherwise a compile time error in the configuration file will occur. .. index:: CONFIGURE_APPLICATION_EXTRA_DRIVERS .. _CONFIGURE_APPLICATION_EXTRA_DRIVERS: CONFIGURE_APPLICATION_EXTRA_DRIVERS ----------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_EXTRA_DRIVERS`` DATA TYPE: device driver entry structures RANGE: Undefined or set of device driver entry structures DEFAULT VALUE: This is not defined by default. DESCRIPTION: ``CONFIGURE_APPLICATION_EXTRA_DRIVERS`` is defined if the application has device drivers it needs to include in the Device Driver Table. This should be defined to the set of device driver entries that will be placed in the table at the *END* of the Device Driver Table. NOTES: None. .. index:: CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER: CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER ---------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER`` 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 Clock Driver is initialized during system initialization. NOTES: The Clock Driver is responsible for providing a regular interrupt which invokes a clock tick directive. The application must define exactly one of the following configuration options * `CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER`, * :ref:`CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`, or * :ref:`CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER`, otherwise a compile time error in the configuration file will occur. .. index:: CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER: CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER ------------------------------------------ CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`` 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 Console Driver is initialized during system initialization. NOTES: The Console Driver is responsible for providing the :file:`/dev/console` device file. This device is used to initialize the standard input, output, and error file descriptors. BSPs should be constructed in a manner that allows :c:func:`printk` to work properly without the need for the Console Driver to be configured. The * :ref:`CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`, * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER`, and * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER` configuration options are mutually exclusive. .. index:: CONFIGURE_APPLICATION_NEEDS_FRAME_BUFFER_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_FRAME_BUFFER_DRIVER: CONFIGURE_APPLICATION_NEEDS_FRAME_BUFFER_DRIVER ----------------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_FRAME_BUFFER_DRIVER`` 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 Frame Buffer Driver is initialized during system initialization. NOTES: Most BSPs do not include support for a Frame Buffer Driver. This is because many boards do not include the required hardware. If this option is defined and the BSP does not have this device driver, then the user will get a link time error for an undefined symbol. .. index:: CONFIGURE_APPLICATION_NEEDS_NULL_DRIVER .. index:: /dev/null .. _CONFIGURE_APPLICATION_NEEDS_NULL_DRIVER: CONFIGURE_APPLICATION_NEEDS_NULL_DRIVER --------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_NULL_DRIVER`` 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 :file:`/dev/null` Driver is initialized during system initialization. NOTES: This device driver is supported by all BSPs. .. index:: CONFIGURE_APPLICATION_NEEDS_RTC_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_RTC_DRIVER: CONFIGURE_APPLICATION_NEEDS_RTC_DRIVER -------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_RTC_DRIVER`` 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 Real-Time Clock Driver is initialized during system initialization. NOTES: Most BSPs do not include support for a real-time clock (RTC). This is because many boards do not include the required hardware. If this is defined and the BSP does not have this device driver, then the user will get a link time error for an undefined symbol. .. index:: CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER: CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER ------------------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER`` 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 Simple Console Driver is initialized during system initialization. NOTES: This device driver is responsible for providing the :file:`/dev/console` device file. This device is used to initialize the standard input, output, and error file descriptors. This device driver reads via :c:func:`getchark`. This device driver writes via :c:func:`rtems_putc`. The Termios framework is not used. There is no support to change device settings, e.g. baud, stop bits, parity, etc. The * :ref:`CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`, * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER`, and * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER` configuration options are mutually exclusive. .. index:: CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER: CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER ------------------------------------------------------ CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER`` 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 Simple Task Console Driver is initialized during system initialization. NOTES: This device driver is responsible for providing the :file:`/dev/console` device file. This device is used to initialize the standard input, output, and error file descriptors. This device driver reads via :c:func:`getchark`. This device driver writes into a write buffer. The count of characters written into the write buffer is returned. It might be less than the requested count, in case the write buffer is full. The write is non-blocking and may be called from interrupt context. A dedicated task reads from the write buffer and outputs the characters via :c:func:`rtems_putc`. This task runs with the least important priority. The write buffer size is 2047 characters and it is not configurable. Use ``fsync(STDOUT_FILENO)`` or ``fdatasync(STDOUT_FILENO)`` to drain the write buffer. The Termios framework is not used. There is no support to change device settings, e.g. baud, stop bits, parity, etc. The * :ref:`CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`, * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER`, and * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER` configuration options are mutually exclusive. .. index:: CONFIGURE_APPLICATION_NEEDS_STUB_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_STUB_DRIVER: CONFIGURE_APPLICATION_NEEDS_STUB_DRIVER --------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_STUB_DRIVER`` 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 Stub Driver is initialized during system initialization. NOTES: This device driver simply provides entry points that return successful and is primarily a test fixture. It is supported by all BSPs. .. index:: CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER: CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER ---------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER`` 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 Benchmark Timer Driver is initialized during system initialization. NOTES: The Benchmark Timer Driver is intended for the benchmark tests of the RTEMS Testsuite. Applications should not use this driver. The application must define exactly one of the following configuration options * :ref:`CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER`, * :ref:`CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`, or * `CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER`, otherwise a compile time error will occur. .. index:: CONFIGURE_APPLICATION_NEEDS_WATCHDOG_DRIVER .. _CONFIGURE_APPLICATION_NEEDS_WATCHDOG_DRIVER: CONFIGURE_APPLICATION_NEEDS_WATCHDOG_DRIVER ------------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_WATCHDOG_DRIVER`` 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 Watchdog Driver is initialized during system initialization. NOTES: Most BSPs do not include support for a watchdog device driver. This is because many boards do not include the required hardware. If this is defined and the BSP does not have this device driver, then the user will get a link time error for an undefined symbol. .. index:: CONFIGURE_APPLICATION_NEEDS_ZERO_DRIVER .. index:: /dev/zero .. _CONFIGURE_APPLICATION_NEEDS_ZERO_DRIVER: CONFIGURE_APPLICATION_NEEDS_ZERO_DRIVER --------------------------------------- CONSTANT: ``CONFIGURE_APPLICATION_NEEDS_ZERO_DRIVER`` 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 :file:`/dev/zero` Driver is initialized during system initialization. NOTES: This device driver is supported by all BSPs. .. index:: CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS .. _CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS: CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS ------------------------------------------ CONSTANT: ``CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS`` DATA TYPE: device driver entry structures RANGE: Undefined or set of device driver entry structures DEFAULT VALUE: This is not defined by default. DESCRIPTION: ``CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS`` is defined if the application has device drivers it needs to include in the Device Driver Table. This should be defined to the set of device driver entries that will be placed in the table at the *FRONT* of the Device Driver Table and initialized before any other drivers *EXCEPT* any BSP prerequisite drivers. NOTES: In some cases, it is used by System On Chip BSPs to support peripheral buses beyond those normally found on the System On Chip. For example, this is used by one RTEMS system which has implemented a SPARC/ERC32 based board with VMEBus. The VMEBus Controller initialization is performed by a device driver configured via this configuration parameter. .. index:: CONFIGURE_MAXIMUM_DRIVERS .. _CONFIGURE_MAXIMUM_DRIVERS: CONFIGURE_MAXIMUM_DRIVERS ------------------------- CONSTANT: ``CONFIGURE_MAXIMUM_DRIVERS`` DATA TYPE: Unsigned integer (``uint32_t``). RANGE: Zero or positive. DEFAULT VALUE: This is computed by default, and is set to the number of device drivers configured using the ``CONFIGURE_APPLICATIONS_NEEDS_XXX_DRIVER`` configuration parameters. DESCRIPTION: ``CONFIGURE_MAXIMUM_DRIVERS`` is defined as the number of device drivers per node. NOTES: If the application will dynamically install device drivers, then this configuration parameter must be larger than the number of statically configured device drivers. Drivers configured using the ``CONFIGURE_APPLICATIONS_NEEDS_XXX_DRIVER`` configuration parameters are statically installed.