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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

idecdrom IDE Device Driver

Purpose

Supports the Integrate Device Electronics (IDE) CD-ROM devices.

Syntax

#include <sys/devinfo.h>
#include <sys/ide.h>
#include <sys/idecdrom.h>

Device-Dependent Subroutines

Typical CD-ROM drive operations are implemented using the open, close, read, and ioctl subroutines.

open and close Subroutines

The openx subroutine is intended primarily for use by the utilities.

The ext parameter passed to the openx subroutine selects the operation to be used for the target device. The /usr/include/sys/idecdrom.h file defines possible values for the ext parameter.

The ext parameter can contain any combination of the following flag values logically ORed together:

IDE_SINGLE Places the selected device in exclusive access mode. Only one process at a time can open a device in exclusive access mode.

A device can be opened in exclusive access mode only if the device is not currently open. If an attempt is made to open a device in exclusive access mode and the device is already open, the subroutine returns a value of -1 and sets the errno global variable to a value of EBUSY.

ioctl Subroutine

ioctl subroutine operations that are used for the idecdrom device driver are:

IOCINFO Returns the devinfo structure defined in the /usr/include/sys/devinfo.h file. The IOCINFO operation is the only operation defined for all device drivers that use the ioctl subroutine. The remaining operations discussed in this article are all specific to CD-ROM devices.
IDE_CDIORDSE Provides a means for issuing a read command to the device and obtaining the target-device sense data when an error occurs. If the IDE_CDIORDSE operation returns a value of -1 and the status_validity field has the ATA_ERROR bit set, valid sense data is returned. Otherwise, target sense data is omitted.

The IDE_CDIORDSE operation is provided for diagnostic use. It allows the limited use of the target device while operating in an active system environment. The arg parameter to the IDE_CDIOROSE operation contains the address of an sc_rdwrt structure. This structure is defined in the /usr/include/sys/scsi.h file.

The devinfo structure defines the maximum transfer size for a read operation. If an attempt is made to transfer more than the maximum, the subroutine returns a value of -1 and sets the errno global variable to a value of EINVAL. Refer to the ATA Packet Interface for CD-ROMS Specification for the format of the request-sense data for a particular device.

Note: The IDE_CDIORDSE operation can be substituted for the DKIORDSE operation when issuing a read command to obtain sense data from a CD-ROM device.
IDE_CDPMR Issues an IDE prevent media removal command when the device has been successfully opened. This command prevents media from being ejected until the device is closed, powered off and then back on, or until a IDE_CDAMR operation is issued. The arg parameter for the IDE_CDPMR operation is null. If the IDE_CDPMR operation is successful, the subroutine returns a value of 0. If the IDE_CDPMR operation fails for any reason, the subroutine returns a value of -1 and sets the errno global variable to a value of EIO.
IDE_CDAMR Issues an allow media removal command when the device has been successfully opened. As a result media can be ejected using either the drive's eject button or the IDE_CDEJECT operation. The arg parameter for this ioctl is null. If the IDE_CDAMR operation is successful, the subroutine returns a value of 0. For any failure of this operation, the subroutine returns a value of -1 and sets the errno global variable to a value of EIO.
IDE_CDEJECT Issues an eject media command to the drive when the device has been successfully opened. The arg parameter for this operation is null. If the IDE_CDEJECT operation is successful, the subroutine returns a value of 0. For any failure of this operation, the subroutine returns a value of -1 and sets the errno variable to a value of EIO.
IDE_CDAUDIO Issues play-audio commands to the specified device and controls the volume on the device's output ports. Play audio commands include: play audio MSF (play audio track index is not supported), pause, resume, stop, determine the number of tracks, and determine the status of a current audio operation. The IDE_CDAUDIO operation plays audio only through the CD-ROM drive's output ports. The arg parameter of this operation is the address of a cd_audio_cmd structure, which is defined in the /usr/include/sys/scdisk.h file. Exclusive access mode is required.

If IDE_CDAUDIO operation is attempted when the device's audio-supported attribute is set to no, the subroutine returns a value of -1 and sets the errno global variable to a value of EINVAL. If the IDE_CDAUDIO operation fails, the subroutine returns a value of -1 and sets the errno global variable to a nonzero value. In this case, the caller should evaluate the returned status bytes to determine why the operation failed and what recovery actions should be taken.

IDE_CDMODE Determines or changes the CD-ROM data mode for the specified device. The CD-ROM data mode specifies what block size and special file are used for data read across the IDE bus from the device.The IDE_CDMODE operation supports the following CD-ROM data modes:
CD_ROM Data Mode 1 2048-byte block size through both raw (dev/rcd*) and block special (/dev/cd*) files
CD_ROM Data Mode 2 Form 1 2048-byte block size through both raw (dev/rcd*) and block special (/dev/cd*) files
CD_ROM Data Mode 2 Form 2 2336-byte block size through the raw (dev/rcd*) special file only
CD_DA (Compact Disc Digital Audio) 2352-byte block size through the raw (dev/rcd*) special file only

The IDE_CDMODE arg parameter contains the address of the mode_form_op structure defined in the /usr/include/sys/scdisk.h file. To have the IDE_CDMODE operation determine or change the CD-ROM data mode, set the action field of the change_mode_form structure to one of the following values:

CD_GET_MODE Returns the current CD-ROM data mode in the cd_mode_form field of the mode_form_op structure, when the device has been successfully opened.
CD_CHG_MODE Changes the CD-ROM data mode to the mode specified in the cd_mode_form field of the mode_form_op structure, when the device has been successfully opened in the exclusive access mode.

If a CD-ROM has not been configured for different data modes, and an attempt is made to change the CD-ROM data mode (by setting the action field of the change_mode_form structure set to CD_CHG_MODE), the subroutine returns a value of -1 and sets the errno global variable to a value of EINVAL.

If the IDE_CDMODE operation for CD_CHG_MODE is attempted when the device is not in exclusive access mode, the subroutine returns a value of -1 and sets the errno global variable to a value of EACCES. For any other failure of this operation, the subroutine returns a value of -1 and sets the errno global variable to a value of EIO.

Device Requirements

IDE CD-ROM drives on AIX have the following hardware requirements:

Error Conditions

Possible errno values for ioctl, open, read, and write subroutines when using the idecdrom device driver include:

EACCES Indicates one of the following circumstances:
  • An attempt was made to open a device currently open exclusive access mode.
  • An IDE_CDMODE ioctl subroutine operation was attempted on a device not in exclusive access mode.
EBUSY An attempt was made to open a session in exclusive access mode on a device already opened.
EFAULT Indicates an illegal user address.
EFORMAT Indicates the target device has unformatted media or media in an incompatible format.
EINPROGRESS Indicates a CD-ROM drive has a play-audio operation in progress.
EINVAL Indicates one of the following circumstances:
  • An IDE_CDAUDIO (play-audio) operation was attempted for a device that is not configured to use the IDE play-audio commands.
  • The read subroutine supplied an nbyte parameter that is not an even multiple of the block size.
  • A sense data buffer length of greater than 255 bytes is not valid for a IDE_CDIORDSE ioctl subroutine operation.
  • The data buffer length exceeded the maximum defined in the devinfo structure for a IDE_CDIORDSE ioctl subroutine operation.
  • An unsupported ioctl subroutine operation was attempted.
  • An attempt was made to configure a device that is still open.
  • An illegal configuration command has been given.
  • An IDE_CDPMR (Prevent Media Removal), IDE_CDAMR (Allow Media Removal), or IDE_CDEJECT (Eject Media) command was sent to a device that does not support removable media.
  • An IDE_CDEJECT (Eject Media) command was sent to a device that currently has its media locked in the drive.
  • The data buffer length exceeded the maximum defined for a strategy operation.
EIO Indicates one of the following circumstances:
  • The target device cannot be located or is not responding.
  • The target device has indicated an unrecovered hardware error.
EMEDIA Indicates one of the following circumstances:
  • The target device has indicated an unrecovered media error.
  • The media was changed.
EMFILE Indicates an open operation was attempted for an adapter that already has the maximum permissible number of opened devices.
ENODEV Indicates one of the following circumstances:
  • An attempt was made to access an undefined device.
  • An attempt was made to close an undefined device.
ENOTREADY Indicates no media is in the drive.
ENXIO Indicates one of the following circumstances:
  • The ioctl subroutine supplied an invalid parameter.
EPERM Indicates the attempted subroutine requires appropriate authority.
ESTALE Indicates a read-only disk was ejected (without first being closed by the user) and then either reinserted or replaced with a second disk.
ETIMEDOUT Indicates an I/O operation has exceeded the given timer value.
EWRPROTECT Indicates one of the following circumstances:
  • An open operation requesting read/write mode was attempted on read-only media.
  • A write operation was attempted to read-only media.

Reliability and Serviceability Information

IDE CD-ROM drives return the following errors:

ABORTED COMMAND Indicates the device ended the command.
GOOD COMPLETION Indicates the command completed successfully.
HARDWARE ERROR Indicates an unrecoverable hardware failure occurred during command execution or during a self-test.
ILLEGAL REQUEST Indicates an illegal command or command parameter.
MEDIUM ERROR Indicates the command ended with an unrecovered media error condition.
NOT READY Indicates the logical unit is offline or media is missing.
RECOVERED ERROR Indicates the command was successful after some recovery was applied.
UNIT ATTENTION Indicates the device has been reset or the power has been turned on.

Error Record Values for Media Errors

The fields defined in the error record template for CD-ROM media errors are:

Comment Indicates CD-ROM read media error.
Class Equals a value of H, which indicates a hardware error.
Report Equals a value of True, which indicates this error should be included when an error report is generated.
Log Equals a value of True, which indicates an error log entry should be created when this error occurs.
Alert Equals a value of False, which indicates this error is not alertable.
Err_Type Equals a value of Perm, which indicates a permanent failure.
Err_Desc Equals a value of 1312, which indicates a disk operation failure.
Prob_Causes Equals a value of 5000, which indicates media.
User_Causes Equals a value of 5100, which indicates the media is defective.
User_Actions Equals the following values:
  • 0000, which indicates problem-determination procedures should be performed
  • 1601, which indicates the removable media should be replaced and retried
Fail_Causes Equals the following values:
  • 5000, which indicates a media failure
  • 6310, which indicates a disk drive failure
Fail_Actions Equals the following values:
  • 0000, which indicates problem-determination procedures should be performed
  • 1601, which indicates the removable media should be replaced and retried
Detail_Data Equals a value of 156, 11, HEX. This value indicates hexadecimal format.
Note: The Detail_Data field in the err_rec structure contains the idecdrom_error_rec structure. The err_rec structure is defined in the /usr/include/sys/errids.h file. The idecdrom_error_rec structure is defined in the /usr/include/sys/ide.h file.

The idecdrom_error_rec structure contains the following fields:

req_sense_data Contains the request-sense information from the particular device that had the error, if it is valid.
reserved2 Contains the segment count, which is the number of megabytes read from the device at the time the error occurred.
reserved3 Contains the number of bytes read since the segment count was last increased.

Refer to the ATA Packet Interface for CD-ROMs Specification for the format of the request-sense data for a particular device.

Error Record Values for Hardware Errors

The fields defined in the error record template for CD-ROM hardware errors, as well as hard-aborted command errors are:

Comment Indicates CD-ROM hardware error.
Class Equals a value of H, which indicates a hardware error.
Report Equals a value of True, which indicates this error should be included when an error report is generated.
Log Equals a value of True, which indicates an error log entry should be created when this error occurs.
Alert Equal to a value of FALSE, which indicates this error is not alertable.
Err_Type Equals a value of Perm, which indicates a permanent failure.
Err_Desc Equals a value of 1312, which indicates a disk operation failure.
Prob_Causes Equals a value of 6310, which indicates disk drive.
Fail_Causes Equals the following values:
  • 6310, which indicates a disk drive failure
  • 6330, which indicates a disk drive electronics failure
Fail_Actions Equals a value of 0000, which indicates problem-determination procedures should be performed.
Detail_Data Equals a value of 156, 11, HEX. This value indicates hexadecimal format.
Note: The Detail_Data field in the err_rec structure contains the idecdrom_error_rec structure. The err_rec structure is defined in the /usr/include/sys/errids.h file. The idecdrom_error_rec structure is defined in the /usr/include/sys/ide.h file.

The idecdrom_error_rec structure contains the following fields:

req_sense_data Contains the request-sense information from the particular device that had the error, if it is valid.
reserved2 Contains the segment count, which is the number of megabytes read from the device at the time the error occurred.
reserved3 Contains the number of bytes read since the segment count was last increased.

Refer to the ATA Packet Interface for CD-ROMs Specification for the format of the request-sense data for a particular device.

Error Record Values for Recovered Errors

The fields defined in the error record template for CD-ROM media errors recovered errors are:

Comment Indicates CD-ROM recovered error.
Class Equals a value of H, which indicates a hardware error.
Report Equals a value of True, which indicates this error should be included when an error report is generated.
Log Equals a value of True, which indicates an error log entry should be created when this error occurs.
Alert Equal to a value of FALSE, which indicates this error is not alertable.
Err_Type Equals a value of Temp, which indicates a temporary failure.
Err_Desc Equals a value of 1312, which indicates a physical volume operation failure.
Prob_Causes Equals the following values:
  • 5000, which indicates a media failure
  • 6310, which indicates a disk drive failure
User_Causes Equals a value of 5100, which indicates media is defective.
User_Actions Equals the following values:
  • 0000, which indicates problem-determination procedures should be performed
  • 1601, which indicates the removable media should be replaced and retried
Fail_Causes Equals the following values:
  • 5000, which indicates a media failure
  • 6310, which indicates a disk drive failure
Fail_Actions Equals the following values:
  • 0000, which indicates problem-determination procedures should be performed
  • 1601, which indicates the removable media should be replaced and retried
Detail_Data Equals a value of 156, 11, HEX. This value indicates hexadecimal format.
Note: The Detail_Data field in the err_rec structure contains the idecdrom_error_rec structure. The err_rec structure is defined in the /usr/include/sys/errids.h file. The idecdrom_error_rec structure is defined in the /usr/include/sys/ide.h file.

The idecdrom_error_rec structure contains the following fields:

req_sense_data Contains the request-sense information from the particular device that had the error, if it is valid.
reserved2 Contains the segment count, which is the number of megabytes read from the device at the time the error occurred.
reserved3 Contains the number of bytes read since the segment count was last increased.

Refer to the ATA Packet Interface for CD-ROMs Specification for the format of the request-sense data for a particular device.

Error Record Values for Unknown Errors

The fields defined in the error record template for CD-ROM media errors unknown errors are:

Comment Indicates CD-ROM unknown failure.
Class Equals a value of H, which indicates a hardware error.
Report Equals a value of True, which indicates this error should be included when an error report is generated.
Log Equals a value of True, which indicates an error log entry should be created when this error occurs.
Alert Equal to a value of FALSE, which indicates this error is not alertable.
Err_Type Equals a value of Unkn, which indicates the type of error is unknown.
Err_Desc Equals a value of FE00, which indicates an undetermined error.
Prob_Causes Equals the following values:
  • 3300, which indicates an adapter failure
  • 5000, which indicates a media failure
  • 6310, which indicates a disk drive failure
Fail_Causes Equals a value of FFFF, which indicates the failure causes are unknown.
Fail_Actions Equals the following values:
  • 0000, which indicates problem-determination procedures should be performed
  • 1601, which indicates the removable media should be replaced and retried
Detail_Data Equals a value of 156, 11, HEX. This value indicates hexadecimal format.
Note: The Detail_Data field in the err_rec structure contains the idecdrom_error_rec structure. The err_rec structure is defined in the /usr/include/sys/errids.h file. The idecdrom_error_rec structure is defined in the /usr/include/sys/ide.h file.

The idecdrom_error_rec structure contains the following fields:

req_sense_data Contains the request-sense information from the particular device that had the error, if it is valid.
reserved2 Contains the segment count, which is the number of megabytes read from the device at the time the error occurred.
reserved3 Contains the number of bytes read since the segment count was last increased.

Refer to the ATA Packet Interface for CD-ROMs Specification for the format of the request-sense data for a particular device.

Special Files

The idecdrom IDE device driver uses raw and block special files in performing its functions.

Attention: Data corruption, loss of data, or loss of system integrity (system crash) will occur if devices supporting paging, logical volumes, or mounted file systems are accessed using block special files. Block special files are provided for logical volumes and disk devices and are solely for system use in managing file systems, paging devices, and logical volumes. These files should not be used for other purposes.

The special files used by the idecdrom, device driver include the following:

/dev/rcd0, /dev/rcd1,..., /dev/rcdn Provide an interface to allow IDE device drivers character access (raw I/O access and control functions) to IDE CD-ROM disks.
/dev/cd0, /dev/cd1,..., /dev/cdn Provide an interface to allow IDE device drivers block I/O access to IDE CD-ROM disks.

The prefix r on a special file name indicates the drive is accessed as a raw device rather than a block device. Performing raw I/O with a CD-ROM drive requires that all data transfers be in multiples of the device block size. Also, all lseek subroutines that are made to the raw device driver must result in a file pointer value that is a multiple of the device block size.

Related Information

Special Files Overview in AIX Version 4 Files Reference.

IDE Subsystem Overview in Aix Version 4.1 Kernel Extensions And Device Support Programming Concepts.

A Typical IDE Driver Transaction Sequence in AIX Version 4.1 Kernel Extensions and Device Support Programming Concepts.

Required IDE Adapter Device Driver ioctl Commands in AIX Version 4.1 Kernel Extensions and Device Support Programming Concepts.

Understanding the Execution of Initiator I/O Requests in AIX Version 4.1 Kernel Extensions and Device Support Programming Concepts.

IDE Error Recovery in AIX Version 4.1 Kernel Extensions and Device Support Programming Concepts.

ataide_buf Structure in AIX Version 4.1 Kernel Extensions and Device Support Programming Concepts.

IDE Adapter Device Driver.

The close subroutine, ioctl or ioctlx subroutine, open, openx, create subroutine, read, readx, readv, or readvx subroutine, write, writex, writev, or writevx subroutine.

cd Special File.

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