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diff --git a/bsp_howto/ata.rst b/bsp_howto/ata.rst deleted file mode 100644 index 1d3546d..0000000 --- a/bsp_howto/ata.rst +++ /dev/null @@ -1,181 +0,0 @@ -.. comment SPDX-License-Identifier: CC-BY-SA-4.0 - -.. COMMENT: COPYRIGHT (c) 1988-2002. -.. COMMENT: On-Line Applications Research Corporation (OAR). -.. COMMENT: All rights reserved. - -ATA Driver -########## - -Terms -===== - -ATA device - physical device attached to an IDE controller - -Introduction -============ - -ATA driver provides generic interface to an ATA device. ATA driver is hardware -independent implementation of ATA standard defined in working draft "AT -Attachment Interface with Extensions (ATA-2)" X3T10/0948D revision 4c, March -18, 1996. ATA Driver based on IDE Controller Driver and may be used for -computer systems with single IDE controller and with multiple as well. Although -current implementation has several restrictions detailed below ATA driver -architecture allows easily extend the driver. Current restrictions are: - -- Only mandatory (see draft p.29) and two optional (READ/WRITE MULTIPLE) - commands are implemented - -- Only PIO mode is supported but both poll and interrupt driven - -The reference implementation for ATA driver can be found in -``cpukit/libblock/src/ata.c``. - -Initialization -============== - -The ``ata_initialize`` routine is responsible for ATA driver -initialization. The main goal of the initialization is to detect and register -in the system all ATA devices attached to IDE controllers successfully -initialized by the IDE Controller driver. - -In the implementation of the driver, the following actions are performed: - -.. code-block:: c - - rtems_device_driver ata_initialize( - rtems_device_major_number major, - rtems_device_minor_number minor, - void *arg - ) - { - initialize internal ATA driver data structure - - for each IDE controller successfully initialized by the IDE Controller driver - if the controller is interrupt driven - set up interrupt handler - - obtain information about ATA devices attached to the controller - with help of EXECUTE DEVICE DIAGNOSTIC command - - for each ATA device detected on the controller - obtain device parameters with help of DEVICE IDENTIFY command - - register new ATA device as new block device in the system - } - -Special processing of ATA commands is required because of absence of -multitasking environment during the driver initialization. - -Detected ATA devices are registered in the system as physical block devices -(see libblock library description). Device names are formed based on IDE -controller minor number device is attached to and device number on the -controller (0 - Master, 1 - Slave). In current implementation 64 minor numbers -are reserved for each ATA device which allows to support up to 63 logical -partitions per device. - -================ ============= =========== ================ -controller minor device number device name ata device minor -================ ============= =========== ================ -0 0 hda 0 -0 1 hdb 64 -1 0 hdc 128 -1 1 hdd 172 -... ... ... ... -================ ============= =========== ================ - -ATA Driver Architecture -======================= - -ATA Driver Main Internal Data Structures ----------------------------------------- - -ATA driver works with ATA requests. ATA request is described by the following -structure: - -.. code-block:: c - - /* ATA request */ - typedef struct ata_req_s { - Chain_Node link; /* link in requests chain */ - char type; /* request type */ - ata_registers_t regs; /* ATA command */ - uint32_t cnt; /* Number of sectors to be exchanged */ - uint32_t cbuf; /* number of current buffer from breq in use */ - uint32_t pos; /* current position in 'cbuf' */ - blkdev_request *breq; /* blkdev_request which corresponds to the ata request */ - rtems_id sema; /* semaphore which is used if synchronous - * processing of the ata request is required */ - rtems_status_code status; /* status of ata request processing */ - int error; /* error code */ - } ata_req_t; - -ATA driver supports separate ATA requests queues for each IDE controller (one -queue per controller). The following structure contains information about -controller's queue and devices attached to the controller: - -.. code-block:: c - - /* - * This structure describes controller state, devices configuration on the - * controller and chain of ATA requests to the controller. - */ - typedef struct ata_ide_ctrl_s { - bool present; /* controller state */ - ata_dev_t device[2]; /* ata devices description */ - Chain_Control reqs; /* requests chain */ - } ata_ide_ctrl_t; - -Driver uses array of the structures indexed by the controllers minor number. - -The following structure allows to map an ATA device to the pair (IDE controller -minor number device is attached to, device number on the controller): - -.. code-block:: c - - /* - * Mapping of RTEMS ATA devices to the following pairs: - * (IDE controller number served the device, device number on the controller) - */ - typedef struct ata_ide_dev_s { - int ctrl_minor;/* minor number of IDE controller serves RTEMS ATA device */ - int device; /* device number on IDE controller (0 or 1) */ - } ata_ide_dev_t; - -Driver uses array of the structures indexed by the ATA devices minor number. - -ATA driver defines the following internal events: - -.. code-block:: c - - /* ATA driver events */ - typedef enum ata_msg_type_s { - ATA_MSG_GEN_EVT = 1, /* general event */ - ATA_MSG_SUCCESS_EVT, /* success event */ - ATA_MSG_ERROR_EVT, /* error event */ - ATA_MSG_PROCESS_NEXT_EVT /* process next ata request event */ - } ata_msg_type_t; - -Brief ATA Driver Core Overview ------------------------------- - -All ATA driver functionality is available via ATA driver ioctl. Current -implementation supports only two ioctls: ``BLKIO_REQUEST`` and -``ATAIO_SET_MULTIPLE_MODE``. Each ATA driver ``ioctl()`` call generates an ATA -request which is appended to the appropriate controller queue depending on ATA -device the request belongs to. If appended request is single request in the -controller's queue then ATA driver event is generated. - -ATA driver task which manages queue of ATA driver events is core of ATA -driver. In current driver version queue of ATA driver events implemented as -RTEMS message queue. Each message contains event type, IDE controller minor -number on which event happened and error if an error occurred. Events may be -generated either by ATA driver ioctl call or by ATA driver task itself. Each -time ATA driver task receives an event it gets controller minor number from -event, takes first ATA request from controller queue and processes it depending -on request and event types. An ATA request processing may also includes sending -of several events. If ATA request processing is finished the ATA request is -removed from the controller queue. Note, that in current implementation maximum -one event per controller may be queued at any moment of the time. - -(This part seems not very clear, hope I rewrite it soon) |