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Emerson MVME147 Building the Packet, Passing Commands to the SCSI Firmware, 2.SCSI Disk Driver

Models: MVME147

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Figure 5-1. SCSI Disk Driver Interface to VERSAdos

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WRITING A DRIVER

Return from the SCSI firmware to the driver is done through the vector supplied in the packet. The VERSAdos driver uses vector $4E (offset $138), and tape driver uses vector $4D (offset $134). These vectors must be initialized to point to a driver routine which handles the return. Refer to the Interface Rules for the SCSI Firmware section in this chapter for details on the return.

The SCSI firmware can accept six commands (average) per peripheral device. A busy error may be returned if too many commands are received for a device depending on the firmware current activities. Until one command has been completed, or abnormally terminated, no other command may be dispatched to the firmware. Commands to any other device may be issued after a "wait for interrupt (open)" ($02) intermediate status, or final status is returned from the SCSI firmware to the driver. For more information, refer to the Interface Rules for the SCSI Firmware section in this chapter.

Figure 5-1. SCSI Disk Driver Interface to VERSAdos

Figure 5-2. SCSI Disk Driver

Building the Packet

Chapter 2 provides the details necessary to build the command packet. After the packet has been built, it needs to be passed to the SCSI firmware.

Passing Commands to the SCSI Firmware

Passing control from the driver to the SCSI firmware can be done by jumping directly to the firmware from the driver. The return from the firmware back to the driver is through the vector supplied within the packet. Because the SCSI firmware can only accept six commands (average) for each device, you may need to do internal queuing if more commands need to be sent to a particular device.

Interface Rules for the SCSI Firmware

SCSI firmware may be called by single or multiple callers.

A single caller to the SCSI firmware is a driver or a server that provides a single return path from the firmware. In other words, a single SCSI return routine handles the status codes that the firmware passes. This definition does not imply that only one return routine is used for interpreting status

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Emerson MVME147 manual Building the Packet, Passing Commands to the SCSI Firmware, Interface Rules for the SCSI Firmware

Contents

Features GENERAL INFORMATIONIntroduction Modes of OperationMVME147 SCSI Firmware Entry Points The SCSI firmware initializes these vectors Equipment Supported CONTROLLE CONTROLLE CONTROLLEDEVICE PARTDevices Supported Under Common Command Set CONTROLLEDEVICE PARTRelated Documentation MOTOROLADOCUMENT TITLE PUBLICATION NUMBERManual Terminology MOTOROLAGENERAL INFORMATION Introduction CUSTOM SCSI PACKETSInitiator Role Custom Packet CUSTOM SCSI PACKETS Initiator Role Custom Packet NOTES PHASE CODE PHASEInitiator Role Custom Packet +$00 +$68 status Note ASYNC the firmware status xxxxxxxx xxxxxxxx Page CUSTOM SCSI PACKETS Initiator Role Custom Packet CUSTOM SCSI PACKETS TARGET Enable Custom Packet TARGET Enable Custom PacketNOTES Status from SCSITARGET Enable Custom Packet TARGET Sequence Custom Packet TARGET Sequence Custom Packet CUSTOM SCSI PACKETS NOTESTARGET Sequence Custom Packet WORDS $04 and $06 CUSTOM SCSI PACKETS TARGET Sequence Custom Packet CUSTOM SCSI PACKETS TARGET Sequence Custom Packet RETRY COUNT. Not used by the TARGET role firmwareCUSTOM SCSI PACKETS Control Flags PACKET RETURN STATUSPacket Return Status SCSI Bit 3 FM Filemark Bit 4 COMMAND RETRY 1 = Retries were performed Bit 5 COMMAND REThe command was retried retry count times Packet Return Status Bit 2 EOM End of mediaPACKET RETURN STATUS Table 3-1.Packet Status Codes Intermediate ReturnCodes CODEFinal Return Codes Table 3-1.Packet Status CodesCODE Intermediate ReturnTable 3-2.Packet Status Codes cont’d SCSI Bus Reset Packet section in ChapterCODE MEANINGRequest-Sense-Data Error-Class7 Codes Table 3-3.Packet Status Codes cont’dController-Dependent CODESCSI Status Returned in Status Phase Table 3-4.Packet Status Codes cont’dCODE MEANINGRequest-Sense-Data Error-Class0 through 6 Codes Table 3-5.Packet Status Codes cont’dCODE Controller-DependentPage PACKET RETURN STATUS SCSI FIRMWARE INTERRUPT STRUCTURE SCSI Firmware Interrupt StructureSCSI FIRMWARE INTERRUPT STRUCTURE WRITING A DRIVER SCSI_CMDSCSI_ACTV SCSI_INTPassing Commands to the SCSI Firmware Building the PacketInterface Rules for the SCSI Firmware Figure 5-1.SCSI Disk Driver Interface to VERSAdosInterface Rules for Multiple Callers WRITING A DRIVER Care must be taken not to modify the contents of WRITING A DRIVER Interface Rules for the SCSI Firmware FUNNEL WRITING A DRIVER Interface Rules for the SCSI Firmware WRITING A DRIVER MOVE.W 2A2,D0 THE CODE BELOW HANDLES FINAL RETURN CODES Interface Rules for a Single Caller WRITING A DRIVER Introduction TARGET ROLE ROUTINESMVME147 SCSI Firmware Background SCSI Versus SASI Rules Custom Sequence PacketCommand Table ScriptEnabling TARGET Role Enabling TARGET Role Servicing the TARGET Requests Servicing the TARGET Requests TARGET ROLE ROUTINES Servicing the TARGET Requests TARGET ROLE ROUTINES Servicing the TARGET Requests TARGET ROLE ROUTINES SCSI PACKETS Table 7-1.SCSI FunctionsIntroduction SCSIRead/Write Packet TableSCSI Functions cont’d SCSIDISK and TAPE Controller logical unit in SG table, if zero SCSI PACKETS Old Packet Supported for Compatibility+$12 in SG table, if zero DMA Scatter/Gather Table Entry Read/Write Packet|function code 3 bits 1 = link to next entryFor example $5 isCOMMAND Attach/Detach Packet all devicesCOMMAND CONTROLLERCOMMAND Attach/Detach Packet all devicesSCSI PACKETS +$1E FM encoding, single Controller type refer xxxxxxxx attributes byte offset +$20 Single track density Drive type 0 = Attach/Detach Packet all devices Example for floppy3½, 5¼ 3½, 5¼,3½, 5¼ 3½, 5¼,3½, 5¼ 3½, 5¼+$04 Minimum read QIC-24 if this is set to 0, the +$00 Reserved Interrupt level +$00 +$9E $00 Format Packet Assign Alternate Sector Packet SCSI COMMAND+$0E Assign Alternate Sector Packet SCSI SCSI PACKETS DEFECT LIST TYPE0 Note 3, NOTES Head Bytes from Index MSW NoteSCSI Bus Reset Packet Controller logical unit SCSI Controller Reset Packet Erase Packet+$12 Rewind Packet Device logical unit Read Block Limits Packet SCSI PACKETS where n = number of blocks or filemarks to Space Status from SCSI The table below shows the write filemarks packet Write Filemarks PacketWrite Filemarks Packet Controller logical unit The controller must be in general or read mode Verify CRC PacketTape Mode Select/Sense Packet Tape Mode Select/Sense Packet Number of tracks on Inquiry Packet +$00 Reserved +$1A Load/Unload Packet +$14 Recover Buffer Data Packet +$0C Request Sense Data Packet Controller logical unit Check Status Packet Open Packet SCSI PACKETSOpen Packet SCSI PACKETS BYTE COMMON COMMAND SET AND DISK OPERATIONBYTE OFFSET BYTE OFFSET BYTEBYTE OFFSET ENTRY NUMBER BYTE OFFSETCOMMON COMMAND SET AND DISK OPERATION NOTESSend mode select command COMMON COMMAND SET AND DISK OPERATION DEFECT LIST DEFECT LIST TYPEBYTE OFFSET NOTESBYTE OFFSET Mode Select HeaderBYTE OFFSET Block Descriptor BYTE OFFSETBYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONNOTES Mode Select Header BYTE OFFSETBlock Descriptor BYTE OFFSETBYTE OFFSET BYTE OFFSETNOTES VALUEMode Select Command CDB BYTE OFFSETVALUE COMMENTSCOMMON COMMAND SET AND DISK OPERATION Mode Select HeaderBYTE OFFSET Block DescriptorPage code BYTE OFFSETBYTE OFFSET BYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONNOTES ATTRIBUTE FLAGS MEDIATYPE Mode Select HeaderCOMMON COMMAND SET AND DISK OPERATION ATTRIBUTE FLAGSMEDIA TYPEBYTE OFFSET BYTE OFFSETNOTES VALUEPIN 34 CONTROL COMMON COMMAND SET AND DISK OPERATIONPin 2 and Pin 34 Definition for High Density Pin 2 and Pin 34 Definition for Low DensityPIN 34 CONTROL PIN 2 CONTROLCOMMENTS Pin 34 = driveA-22