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Emerson MVME147 manual Writing A Driver

Models: MVME147

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WRITING A DRIVER

Command status processing is the result of a firmware return to the vector specified in the command packet. If this decoupling exists, the command entry execution can only occur if the processor is not tied up performing SCSI firmware functions or performing command status functions. That is, for the processor to execute the command entry functions, it cannot be at the same time executing command status functions. At the time the command is passed to the driver/server, the command entry code may go ahead and send the command to the firmware without hesitation.

Rule 2:	INTERMEDIATE RETURNS MUST
	REENTER AT

	REACTIVATION OR RTE ENTRY.

The following is a list of intermediate status return codes provided by the firmware (intermediate status codes have bit 15 set):

$xx02: The SCSI firmware returns this code if a disconnect occurred on the bus or if firmware is waiting for SCSI controller chip to interrupt. Again, no action is required for this status other than servicing the RTE (13) bit.

$xx04: A message was received by the firmware that was either uninterpretable or was received in TARGET role. You are responsible for the interpretation of extended messages in initiator and TARGET roles. The MVME147 is still threaded on the bus when this status is passed to the user. The user routine is responsible for interpreting the message and for the proper return point. If bit 13 of the returned status is set, the return is to the reactivation entry ($FFFE0782), and if bit 13 of the returned status is clear, the return is to the RTE entry ($FFFE079A) and register A3 must remain intact. For this status, an RTE is only "remembered for the next exit". If the RTE bit is 0 with this status, an RTE is required. If this condition occurs, address register A3 is pointing to a register list.

$xx06: In TARGET role, a command has been received and the SCSI firmware stored in the command table. The firmware returns this intermediate status to alert you to service the command and to return to either the reactivation entry ($FFFE0782) no

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Emerson MVME147 manual Writing A Driver

Contents

Introduction FeaturesGENERAL INFORMATION Modes of OperationMVME147 SCSI Firmware Entry Points The SCSI firmware initializes these vectors Equipment Supported CONTROLLE DEVICE CONTROLLECONTROLLE PARTDEVICE Devices Supported Under Common Command SetCONTROLLE PARTDOCUMENT TITLE Related DocumentationMOTOROLA PUBLICATION NUMBERManual Terminology MOTOROLAGENERAL INFORMATION Initiator Role Custom Packet CUSTOM SCSI PACKETSIntroduction 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 Packet Return Status PACKET RETURN STATUSControl Flags SCSI The command was retried retry count times Bit 3 FM Filemark Bit 4 COMMAND RETRY1 = Retries were performed Bit 5 COMMAND RE Packet Return Status Bit 2 EOM End of mediaPACKET RETURN STATUS Codes Table 3-1.Packet Status CodesIntermediate Return CODECODE Final Return CodesTable 3-1.Packet Status Codes Intermediate ReturnCODE Table 3-2.Packet Status Codes cont’dSCSI Bus Reset Packet section in Chapter MEANINGController-Dependent Request-Sense-Data Error-Class7 CodesTable 3-3.Packet Status Codes cont’d CODECODE SCSI Status Returned in Status PhaseTable 3-4.Packet Status Codes cont’d MEANINGCODE Request-Sense-Data Error-Class0 through 6 CodesTable 3-5.Packet Status Codes cont’d Controller-DependentPage PACKET RETURN STATUS SCSI FIRMWARE INTERRUPT STRUCTURE SCSI Firmware Interrupt StructureSCSI FIRMWARE INTERRUPT STRUCTURE SCSI_ACTV WRITING A DRIVERSCSI_CMD SCSI_INTInterface Rules for the SCSI Firmware Passing Commands to the SCSI FirmwareBuilding the Packet 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 MVME147 SCSI Firmware Background TARGET ROLE ROUTINESIntroduction 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 Introduction SCSI PACKETSTable 7-1.SCSI Functions SCSISCSI Functions cont’d Read/Write PacketTable SCSIDISK and TAPE Controller logical unit in SG table, if zero SCSI PACKETS Old Packet Supported for Compatibility+$12 in SG table, if zero |function code 3 bits DMA Scatter/Gather Table EntryRead/Write Packet 1 = link to next entryFor example $5 isCOMMAND COMMANDAttach/Detach Packet all devices 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 = 3½, 5¼ Attach/Detach Packet all devicesExample for floppy 3½, 5¼,3½, 5¼ 3½, 5¼3½, 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 Write Filemarks Packet Write Filemarks PacketThe table below shows the write 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 OFFSET COMMON COMMAND SET AND DISK OPERATIONBYTE BYTE OFFSET BYTEBYTE OFFSET ENTRY NUMBER BYTE OFFSETCOMMON COMMAND SET AND DISK OPERATION NOTESSend mode select command COMMON COMMAND SET AND DISK OPERATION BYTE OFFSET DEFECT LISTDEFECT LIST TYPE NOTESBYTE OFFSET Mode Select HeaderBYTE OFFSET Block Descriptor BYTE OFFSETNOTES COMMON COMMAND SET AND DISK OPERATIONBYTE OFFSET Block Descriptor Mode Select HeaderBYTE OFFSET BYTE OFFSETNOTES BYTE OFFSETBYTE OFFSET VALUEVALUE Mode Select Command CDBBYTE OFFSET COMMENTSBYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONMode Select Header Block DescriptorBYTE OFFSET BYTE OFFSETPage code NOTES COMMON COMMAND SET AND DISK OPERATIONBYTE OFFSET TYPE ATTRIBUTE FLAGSMEDIA Mode Select HeaderMEDIA COMMON COMMAND SET AND DISK OPERATIONATTRIBUTE FLAGS TYPENOTES BYTE OFFSETBYTE OFFSET VALUEPin 2 and Pin 34 Definition for High Density PIN 34 CONTROLCOMMON COMMAND SET AND DISK OPERATION Pin 2 and Pin 34 Definition for Low DensityCOMMENTS PIN 34 CONTROLPIN 2 CONTROL Pin 34 = driveA-22