IDE_REQUEST_BLOCK structure

The IDE_REQUEST_BLOCK structure defines an IDE request block.

Syntax


typedef struct _IDE_REQUEST_BLOCK {
  USHORT Function;
  UCHAR  IrbStatus;
  UCHAR  AtaStatus;
  UCHAR  AtaError;
  UCHAR  Channel;
  UCHAR  TargetId;
  UCHAR  Lun;
  UCHAR  CdbLength;
  UCHAR  SenseInfoBufferLength;
  UCHAR  SenseInfoBufferType;
  UCHAR  QueueTag;
  ULONG  ReservedAsUlong;
  ULONG  IrbFlags;
  ULONG  TimeOutValue;
  ULONG  DataTransferLength;
  PVOID  IrbExtension;
  PVOID  DataBuffer;
  PVOID  SenseInfoBuffer;
  PVOID  NextIrb;
  PVOID  Reserved;
  union {
    IDE_TASK_FILE  IdeTaskFile;
    UCHAR          Cdb[16];
    IDE_POWER_INFO PowerChange;
    UCHAR          AsUChar[16];
  };
} IDE_REQUEST_BLOCK, *PIDE_REQUEST_BLOCK;

Members

Function

Specifies the category that the request belongs to. The table below describes the classification of the I/O requests.

Function

Sub-commands

Description

IRB_FUNCTION_ATA_COMMAND

IRB_FUNCTION_ATA_IDENTIFY

IRB_FUNCTION_ATA_READ

IRB_FUNCTION_ATA_WRITE

IRB_FUNCTION_ATA_FLUSH

IRB_FUNCTION_ATA_SMART

Indicates that the IRB contains an IdeTaskFile that describes the ATA command. The sub-commands indicate finer grouping of request for faster lookup.

IRB_FUNCTION_ATAPI_COMMAND

IRB_FUNCTION_REQUEST_SENSE

Indicates that the IRB contains a CDB that describes the ATAPI command.

IRB_FUNCTION_MINIPORT_COMMAND

IRB_FUNCTION_ADAPTER_FLUSH

IRB_FUNCTION_SHUTDOWN

IRB_FUNCTION_POWER_CHANGE

IRB_FUNCTION_POWER_REBOOT

IRB_FUNCTION_LUN_RESET

IRB_FUNCTION_MINIPORT_IOCTL

Indicates that the IRB is for the miniport. It is the responsibility of the miniport to interpret the command appropriately.

 

IrbStatus

The miniport must set this member to indicates the status of the specified operation. The table below describes the various IrbStatus values and their meaning.

Value

Meaning

IRB_STATUS_PENDING

Indicates that the request is in progress. The port driver initializes IrbStatus to this value. A miniport driver should never set the IrbStatus member to this value.

IRB_STATUS_SUCCESS

Indicates that the request was completed successfully.

IRB_STATUS_DATALENGTH_MISMATCH

Indicates that a data underrun or overrun error occurred. The miniport must update the DataTransferLength field in the IRB to indicate the actual amount of data that was transferred in the case of an underrun.

IRB_STATUS_DEVICE_ERROR

Indicates that the device returned an error. The miniport driver must update the AtaStatus and AtaError fields in the Irb to the contents of the device ATA status and error register at the completion of the command.

IRB_STATUS_INVALID_REQUEST

Indicates that the miniport does not support the given request.

IRB_STATUS_BUS_RESET

Indicates that a bus reset occurred while processing the given request.

IRB_STATUS_SELECTION_TIMEOUT

Indicates that the destination device could not be selected.

IRB_STATUS_BUSY

Indicates that the device is busy. The port driver retries any request completed with this status. A request completed with busy status is retried only once. It is the responsibility of the miniport driver to pause the request queue using AtaPortDeviceBusy if the device cannot handle request for a certain period of time.

IRB_STATUS_AUTOSENSE_VALID

IRB_STATUS_AUTOSENSE_VALID is a bitmask that indicates valid sense data in the SenseInfoBuffer member of the IRB.

IRB_STATUS_RETURN_TASKFILE_VALID

IRB_STATUS_RETURN_TASKFILE_VALID is a bitmask that indicates a valid return task file in the SenseInfoBuffer member of the IRB.

 

AtaStatus

Indicates the status returned by the device in its status register. The miniport driver should update this field when completing an IRB with IRB_STATUS_DEVICE_ERROR.

AtaError

Indicates the error value returned by the device in its error register. The miniport driver should update this field when completing an IRB with IRB_STATUS_DEVICE_ERROR.

Channel

Specifies the channel number.

TargetId

Specifies the target ID of the device.

Lun

Specifies the logical unit number of the device.

CdbLength

Specifies the length in bytes of the buffer pointed to by Cdb.

SenseInfoBufferLength

Specifies the length in bytes of the buffer pointed to by SenseInfoBuffer.

SenseInfoBufferType

Specifies the type of data structure returned in SenseInfoBuffer. Because ATA commands don't have a need for the request sense command, ATA_PASS_THROUGH commands use SenseInfoBuffer to return task file information. For ATA_PASS_THROUGH commands, as identified in the IrbFlags member, the appropriate return TaskFile size should be reported as either SENSE_INFO_BUFFER_RETURN_TYPE_28BIT_TASKFILE or

SENSE_INFO_BUFFER_RETURN_TYPE_48BIT_TASKFILE.

QueueTag

The queue tag for this IRB. The port driver sets this field to 0.

ReservedAsUlong

Reserved for future use.

IrbFlags

Qualifies the request with ceratin actions that need to be performed. The table below describes them in detail.

Flag

Description

IRB_FLAGS_DRDY_REQUIRED

Indicates that the miniport driver must wait for the device to set the DRDY bit in the ATA status register before issuing this command.

IRB_FLAGS_USE_DMA

Indicates that the request has an associated scatter/gather list and the miniport driver could use DMA to transfer data for this request.

IRB_FLAGS_MAP_BUFFERS

Indicates that the DataBuffer field in the IRB is mapped. The miniport can safely access DataBuffer when this flag is set. The miniport driver must not access DataBuffer if the flag is not set. The miniport driver could request the port driver to map the data buffer by setting this flag in the IRB in its IdeHwBuildIo routine.

IRB_FLAGS_48BIT

Indicates that the ATA command in the IRB belongs to the 48 bit LBA feature set. The Previous field in the _IDE_TASK_FILE structure is valid when this flag is set.

IRB_FLAGS_PIO_MULTIPLE

Indicates that the ATA command is to be transferred using the ATA PIO Multiple method.

IRB_FLAGS_RETURN_RESULTS

Indicates that the ATA return task file is to be copied to SenseInfoBuffer.

IRB_FLAGS_DATA_IN

Indicates that the data is to be transferred from the device to the host system (a read operation).

IRB_FLAGS_DATA_OUT

Indicates that the data is to be transferred to the device from the host system ( a write operation).

IRB_FLAGS_DISCARDABLE

Indicates that the command shall be done in a best effort manner. (note: this is not currently employed by ATAport).

IRB_FLAGS_HIGH_PRIORITY

Indicates that this IRB is to be processed as soon as possible, before non-high-priority IRBs currently in the ATA miniport.

 

TimeOutValue

Indicates the time in seconds after which the request will time out.

DataTransferLength

Contains the length in bytes of the data buffer that contains data to be transferred.

IrbExtension

Pointer to the per-request extension allocated by the port driver.

DataBuffer

Pointer to the buffer where the data resides.

SenseInfoBuffer

Pointer to the buffer which holds the sense data.

NextIrb

Pointer to the next IRB to be processed. The port driver sets this to NULL. The miniport driver can use this field to link IRBs together.

Reserved

Reserved for future use.

IdeTaskFile

Contains a structure of type IDE_TASK_FILE that holds the IDE task file for the indicated controller. This member is defined whenever the result of a bitwise AND between the Function member and IRB_FUNCTION_ATA_COMMAND is nonzero.

Cdb

Contains a command descriptor block (CDB). This member is defined whenever the result of a bitwise AND between the Function member and IRB_FUNCTION_ATAPI_COMMAND is nonzero.

PowerChange

Indicates an enumeration value of type POWER_CHANGE_INFO that defines a power state transition. This member is defined whenever Function is equal to IRB_FUNCTION_POWER_CHANGE.

AsUChar

Provides a means of accessing members IdeTaskFile, PowerChange, and Cdb as unsigned character data.

Remarks

The IDE_REQUEST_BLOCK structure provides a functionality similar to the SCSI_REQUEST_BLOCK but with characteristics more suitable for managing devices on an IDE bus.

Requirements

Header

Irb.h (include Irb.h)

See also

AtaportDeviceBusy
IDE_TASK_FILE
POWER_CHANGE_INFO
SCSI_REQUEST_BLOCK

 

 

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