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Emerson MVME147 Writing A Driver, Scsi_Cmd, Scsi Actv, Scsi_Int, Scsi_Fun, Scsi_Ca, Scsi_Rte

Models: MVME147

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WRITING A DRIVER

WRITING A DRIVER

5

Introduction

This chapter covers information essential in writing a driver to support the SCSI interface in interrupt mode. A driver for non-interrupt mode is a trivial subset of the interrupt mode driver. The approach taken is to describe the major sections of a driver that need to be written. The examples shown have been extracted from the VERSAdos SCSI driver, and are dependent on the driver interface to the VERSAdos operating system. For this interface, see Figure 5-1. For details of the interaction between the driver and the SCSI firmware, see Figure 5-2.

Any driver that communicates to the SCSI firmware starts by building (for single callers) a command packet in memory and calling the command entry point SCSI_CMD in the MVME147Bug. The address of the packet is contained in register A2.

Access to the six SCSI entry points is provided through the use of a jump table located within the beginning of the MVME147 debug monitor. The jump table entry points and their SCSI firmware functions are shown in the following list.

SCSI_CMD	EQU	$FFFE077C	SCSI command entry.
SCSI_ACTV	EQU	$FFFE0782	SCSI command
			reactivation entry.
SCSI_INT	EQU	$FFFE0788	SCSI interrupt entry.
SCSI_FUN	EQU	$FFFE078E	FUNNEL command
			entry.
SCSI_CA	EQU	$FFFE0794	Come-again entry.
SCSI_RTE	EQU	$FFFE079A	RTE entry.

Interrupts from the SCSI controller chip are through vector $45 (offset $114). Interrupts from the MVME147 SCSI DMA channel are through vector $46 (offset $118). The self interrupts from the MVME147 SCSI firmware use the vector $4B (offset $12C) to return control to SCSI firmware. The SCSI firmware sets these vectors to point to its interrupt entry point.

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Emerson MVME147 manual Writing A Driver, Scsi_Cmd, Scsi Actv, Scsi_Int, Scsi_Fun, Scsi_Ca, Scsi_Rte, Introduction

Contents

Modes of Operation FeaturesGENERAL INFORMATION IntroductionMVME147 SCSI Firmware Entry Points The SCSI firmware initializes these vectors Equipment Supported CONTROLLE PART CONTROLLECONTROLLE DEVICEPART Devices Supported Under Common Command SetCONTROLLE DEVICEPUBLICATION NUMBER Related DocumentationMOTOROLA DOCUMENT TITLEMOTOROLA Manual TerminologyGENERAL INFORMATION Initiator Role Custom Packet CUSTOM SCSI PACKETSIntroduction CUSTOM SCSI PACKETS Initiator Role Custom Packet Page PHASE PHASE CODEInitiator 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 PacketStatus from SCSI NOTESTARGET Enable Custom Packet TARGET Sequence Custom Packet TARGET Sequence Custom Packet NOTES CUSTOM SCSI PACKETSTARGET Sequence Custom Packet WORDS $04 and $06 CUSTOM SCSI PACKETS TARGET Sequence Custom Packet CUSTOM SCSI PACKETS RETRY COUNT. Not used by the TARGET role firmware TARGET Sequence Custom PacketCUSTOM SCSI PACKETS Packet Return Status PACKET RETURN STATUSControl Flags SCSI Packet Return Status Bit 2 EOM End of media Bit 3 FM Filemark Bit 4 COMMAND RETRY1 = Retries were performed Bit 5 COMMAND RE The command was retried retry count timesPACKET RETURN STATUS CODE Table 3-1.Packet Status CodesIntermediate Return CodesIntermediate Return Final Return CodesTable 3-1.Packet Status Codes CODEMEANING Table 3-2.Packet Status Codes cont’dSCSI Bus Reset Packet section in Chapter CODECODE Request-Sense-Data Error-Class7 CodesTable 3-3.Packet Status Codes cont’d Controller-DependentMEANING SCSI Status Returned in Status PhaseTable 3-4.Packet Status Codes cont’d CODEController-Dependent Request-Sense-Data Error-Class0 through 6 CodesTable 3-5.Packet Status Codes cont’d CODEPage PACKET RETURN STATUS SCSI Firmware Interrupt Structure SCSI FIRMWARE INTERRUPT STRUCTURESCSI FIRMWARE INTERRUPT STRUCTURE SCSI_INT WRITING A DRIVERSCSI_CMD SCSI ACTVFigure 5-1.SCSI Disk Driver Interface to VERSAdos Passing Commands to the SCSI FirmwareBuilding the Packet Interface Rules for the SCSI FirmwareInterface 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 Custom Sequence Packet SCSI Versus SASI RulesScript Command TableEnabling 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 SCSI PACKETSTable 7-1.SCSI Functions IntroductionSCSI Read/Write PacketTable SCSI Functions cont’dDISK and TAPE Controller logical unit in SG table, if zero Old Packet Supported for Compatibility SCSI PACKETS+$12 in SG table, if zero 1 = link to next entryFor example $5 is DMA Scatter/Gather Table EntryRead/Write Packet |function code 3 bitsCONTROLLER COMMANDAttach/Detach Packet all devices COMMANDAttach/Detach Packet all devices COMMANDSCSI 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, 5¼3½, 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 COMMAND Assign Alternate Sector Packet SCSI+$0E Assign Alternate Sector Packet SCSI DEFECT LIST TYPE SCSI PACKETS0 Note 3, Head Bytes from Index MSW Note NOTESSCSI Bus Reset Packet Controller logical unit Erase Packet SCSI Controller Reset 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 SCSI PACKETS Open PacketOpen Packet SCSI PACKETS BYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONBYTE BYTE OFFSET BYTEBYTE OFFSET BYTE OFFSET ENTRY NUMBERNOTES COMMON COMMAND SET AND DISK OPERATIONSend mode select command COMMON COMMAND SET AND DISK OPERATION NOTES DEFECT LISTDEFECT LIST TYPE BYTE OFFSETBYTE OFFSET Mode Select HeaderBYTE OFFSET BYTE OFFSET Block DescriptorBYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONBYTE OFFSET BYTE OFFSETMode Select Header Block DescriptorVALUE BYTE OFFSETBYTE OFFSET NOTESCOMMENTS Mode Select Command CDBBYTE OFFSET VALUEBlock Descriptor COMMON COMMAND SET AND DISK OPERATIONBYTE OFFSET Mode Select HeaderBYTE OFFSET BYTE OFFSETPage code NOTES COMMON COMMAND SET AND DISK OPERATIONBYTE OFFSET BYTE OFFSET ATTRIBUTE FLAGSMEDIA TYPETYPE COMMON COMMAND SET AND DISK OPERATIONATTRIBUTE FLAGS MEDIAVALUE BYTE OFFSETBYTE OFFSET NOTESPin 2 and Pin 34 Definition for Low Density PIN 34 CONTROLCOMMON COMMAND SET AND DISK OPERATION Pin 2 and Pin 34 Definition for High DensityPin 34 = drive PIN 34 CONTROLPIN 2 CONTROL COMMENTSA-22