;
;=============================================================================
;   SCSI DISK DRIVER FOR 5380
;=============================================================================
;
; DISK DEVICE DRIVER FOR THE 5380 SCSI CHIP.
; DERIVED FROM CODE PROVIDED BY JAY COTTON.
;
; TODO:
;
; NOTES:
;
SCSIBASE		.EQU	$40
;
; SCSI DEVICE STATUS CODES
;
SCSI_STOK		.EQU	0
SCSI_STNOMEDIA		.EQU	-1
SCSI_STIOERR		.EQU	-2
SCSI_STTO		.EQU	-3
SCSI_STNOTRDY		.EQU	-4
;
; NCR 5380 I/O REGISTERS
;
SCSI_SR_CSD	.EQU	SCSIBASE	; CURRENT SCSI DATA
SCSI_SR_ICR	.EQU	SCSIBASE + $01	; INITIATOR COMMAND
SCSI_SR_MR	.EQU	SCSIBASE + $02	; MODE
SCSI_SR_TCR	.EQU	SCSIBASE + $03	; TARGET COMMAND
SCSI_SR_CSBS	.EQU	SCSIBASE + $04	; CURRENT SCSI BUS STAT.
SCSI_SR_BSR	.EQU	SCSIBASE + $05	; BUS STATUS
SCSI_SR_IDR	.EQU	SCSIBASE + $06	; INITIATOR DMA RECV.
SCSI_SR_RPI	.EQU	SCSIBASE + $07	; RESET PARITY/IRQ
;
; NCR 5380 OUTPUT ONLY REGISTERS
;
SCSI_SR_ODR	.EQU	SCSIBASE	; OUTPUT DATA
SCSI_SR_SER	.EQU	SCSIBASE + $04	; SELECT ENABLE
SCSI_SR_SDS	.EQU	SCSIBASE + $05	; START DMA SEND
SCSI_SR_SDTR	.EQU	SCSIBASE + $06	; START TARGET DMA RECV.
SCSI_SR_SDIR	.EQU	SCSIBASE + $07	; START INITIATOR DMA RECV.
;
; SCSI CURRENT BUS STATUS BIT MASKS
;
SCSI_SM_RST	.EQU	$80		; RESET
SCSI_SM_BSY	.EQU	$40		; BUSY
SCSI_SM_REQ	.EQU	$20		; REQUEST
SCSI_SM_MSG	.EQU	$10		; MESSAGE
SCSI_SM_CD	.EQU	$08		; CMD/DATA
SCSI_SM_IO	.EQU	$04		; IN/OUT
SCSI_SM_SEL	.EQU	$02		; SELECT
SCSI_SM_DBP	.EQU	$01		; PARITY BIT
;
SCSI_SM_PHM	.EQU	$08		; PHASE MATCH BIT
;
; SDCI DEVICE CONFIGURATION
;
; PER DEVICE DATA OFFSETS IN CFG BLOCK
;
SCSI_DEV	.EQU	0		; OFFSET OF DEVICE NUMBER (BYTE)
SCSI_IOBASE	.EQU	1		; IO BASE ADDRESS (BYTE)
SCSI_LUN	.EQU	2		; TARGET LUN
SCSI_STAT	.EQU	3		; LAST STATUS (BYTE)
SCSI_MEDCAP	.EQU	4		; MEDIA CAPACITY (DWORD)
SCSI_LBA	.EQU	8		; OFFSET OF LBA (DWORD)
;
;--------------------------------------------------------------------------------------------------
;   HBIOS MODULE HEADER
;--------------------------------------------------------------------------------------------------
;
ORG_SCSI	.EQU	$
;
	.DW	SIZ_SCSI		; MODULE SIZE
	.DW	SCSI_INITPHASE		; ADR OF INIT PHASE HANDLER
;
SCSI_INITPHASE:
	; INIT PHASE HANDLER, A=PHASE
	;CP	HB_PHASE_PREINIT	; PREINIT PHASE?
	;JP	Z,SCSI_PREINIT		; DO PREINIT
	CP	HB_PHASE_INIT		; INIT PHASE?
	JP	Z,SCSI_INIT		; DO INIT
	RET				; DONE
;
SCSI_CFGSIZ	.EQU	12		; SIZE OF CFG TBL ENTRIES
;
SCSI_CFGTBL:
;
#IF (SCSICNT >= 1)
;
SCSI0_CFG:
	.DB	$FE			; DRIVER DEVICE NUMBER (FILLED DYNAMICALLY)
	.DB	SCSIBASE		; IO BASE ADDRESS
	.DB	SCSI0_LUN		; SCSI TARGET LUN
	.DB	SCSI_STNOTRDY		; DEVICE STATUS
	.DW	$0000,$0010		; DEVICE CAPACITY (BLOCKS)
	.DW	0,0			; CURRENT LBA
;
	DEVECHO	"SCSI: IO="
	DEVECHO	SCSIBASE
	DEVECHO ", TGT ID="
	DEVECHO SCSI_TID
	DEVECHO ", LUN="
	DEVECHO SCSI0_LUN
	DEVECHO	"\n"
#ENDIF
;
#IF (SCSICNT >= 2)
	.DB	$FE			; DRIVER DEVICE NUMBER (FILLED DYNAMICALLY)
	.DB	SCSIBASE		; IO BASE ADDRESS
	.DB	SCSI1_LUN		; SCSI TARGET LUN
	.DB	SCSI_STNOTRDY		; DEVICE STATUS
	.DW	$0000,$0010		; DEVICE CAPACITY (BLOCKS)
	.DW	0,0			; CURRENT LBA
;
	DEVECHO	"SCSI: IO="
	DEVECHO	SCSIBASE
	DEVECHO ", TGT ID="
	DEVECHO SCSI_TID
	DEVECHO ", LUN="
	DEVECHO SCSI1_LUN
	DEVECHO	"\n"
#ENDIF
;
#IF ($ - SCSI_CFGTBL) != (SCSICNT * SCSI_CFGSIZ)
	.ECHO	"*** INVALID SCSI CONFIG TABLE ***\n"
#ENDIF
;
	.DB	$FF			; END OF TABLE MARKER
;
;=============================================================================
; INITIALIZATION ENTRY POINT
;=============================================================================
;
SCSI_INIT:
	CALL	NEWLINE			; FORMATTING
	PRTS("SCSI:$")			; TAG
;
	PRTS(" IO=0x$")			; LABEL FOR IO ADDRESS
	LD	A,SCSIBASE		; GET IO BASE ADDRES
	CALL	PRTHEXBYTE		; DISPLAY IT
;
	CALL	SCSI_DETECT		; DETECT THE SCSI INTERFACE
	JR	Z,SCSI_INIT1		; IF FOUND CONTINUE
	PRTS(" NOT PRESENT$")		; SHOW NOT PRESENT
	XOR	A			; SUCCESS
	RET				; AND BAIL OUT
;
SCSI_INIT1:
	PRTS(" TGT_ID=$")		; LABEL FOR IO ADDRESS
	LD	A,SCSI_TID		; GET IO BASE ADDRES
	CALL	PRTDEC8			; DISPLAY IT
;
	XOR	A			; ZERO ACCUM
	LD	(SCSI_DEVNUM),A		; INIT DEV UNIT NUM FOR DYNAMIC ASSIGNMENT
	LD	IY,SCSI_CFGTBL		; POINT TO START OF CONFIG TABLE
;
SCSI_INIT2:
	LD	A,(IY)			; LOAD FIRST BYTE TO CHECK FOR END
	CP	$FF			; CHECK FOR END OF TABLE VALUE
	RET	Z			; RETURN IF DONE
;
	CALL	SCSI_INIT3		; REGISTER & INIT DEVICE
;
	LD	DE,SCSI_CFGSIZ		; SIZE OF CFG TABLE ENTRY
	ADD	IY,DE			; BUMP POINTER
	JP	SCSI_INIT2		; AND LOOP
;
SCSI_INIT3:
	; UPDATE DRIVER RELATIVE UNIT NUMBER IN CONFIG TABLE
	LD	A,(SCSI_DEVNUM)		; GET NEXT UNIT NUM TO ASSIGN
	LD	(IY+SCSI_DEV),A		; UPDATE IT
	INC	A			; BUMP TO NEXT UNIT NUM TO ASSIGN
	LD	(SCSI_DEVNUM),A		; SAVE IT
;
	; ADD UNIT TO GLOBAL DISK UNIT TABLE
	LD	BC,SCSI_FNTBL		; BC := FUNC TABLE ADR
	PUSH	IY			; CFG ENTRY POINTER
	POP	DE			; COPY TO DE
	CALL	DIO_ADDENT		; ADD ENTRY TO GLOBAL DISK DEV TABLE
;
	CALL	SCSI_PRTPREFIX		; TAG FOR ACTIVE DEVICE
;
	PRTS(" LUN=$")			; LUN LABEL
	LD	A,(IY+SCSI_LUN)		; LOAD LUN
	CALL	PRTDEC8			; DISPLAY IT
;
	CALL	SCSI_INITDEV		; INITIALIZE DEVICE
#IF (SCSITRACE < 2)
	JP	NZ,SCSI_PRTSTATSTR	; IF ERROR, EXIT VIA PRINT
#ELSE
	RET	NZ
#ENDIF
;
	; PRINT STORAGE CAPACITY (BLOCK COUNT)
	PRTS(" BLOCKS=0x$")		; PRINT FIELD LABEL
	LD	A,SCSI_MEDCAP		; OFFSET TO CAPACITY FIELD
	CALL	LDHLIYA			; HL := IY + A, REG A TRASHED
	CALL	LD32			; GET THE CAPACITY VALUE
	CALL	PRTHEX32		; PRINT HEX VALUE
;
	; PRINT STORAGE SIZE IN MB
	PRTS(" SIZE=$")			; PRINT FIELD LABEL
	LD	B,11			; 11 BIT SHIFT TO CONVERT BLOCKS --> MB
	CALL	SRL32			; RIGHT SHIFT
	CALL	PRTDEC32		; PRINT DWORD IN DECIMAL
	PRTS("MB$")			; PRINT SUFFIX
;
	; PRINT INQUIRY DATA (STILL IN HB_WRKBUF FROM INITDEV)
	CALL	PC_SPACE		; FORMATTING
	CALL	PC_LBKT			; FORMATTING
	LD	HL,HB_WRKBUF+8		; START OF ASCII DATA
	LD	B,28			; VENDOR, PRODUCT, AND REVISTION FIELDS
SCSI_INIT4:
	LD	A,(HL)			; LOAD NEXT CHAR
	CALL	COUT			; PRINT IT
	INC	HL			; BUMP BUFFER POINTER
	DJNZ	SCSI_INIT4		; LOOP AS NEEDED
	CALL	PC_RBKT			; FORMATTING
;
SCSI_INIT5:
	XOR	A			; SUCCESS
	RET
;
;=============================================================================
; DRIVER FUNCTION TABLE
;=============================================================================
;
SCSI_FNTBL:
	.DW	SCSI_STATUS
	.DW	SCSI_RESET
	.DW	SCSI_SEEK
	.DW	SCSI_READ
	.DW	SCSI_WRITE
	.DW	SCSI_VERIFY
	.DW	SCSI_FORMAT
	.DW	SCSI_DEVICE
	.DW	SCSI_MEDIA
	.DW	SCSI_DEFMED
	.DW	SCSI_CAP
	.DW	SCSI_GEOM
#IF (($ - SCSI_FNTBL) != (DIO_FNCNT * 2))
	.ECHO	"*** INVALID SCSI FUNCTION TABLE ***\n"
#ENDIF
;
SCSI_VERIFY:
SCSI_FORMAT:
SCSI_DEFMED:
	SYSCHKERR(ERR_NOTIMPL)		; NOT IMPLEMENTED
	RET
;
;
;
SCSI_READ:
	CALL	HB_DSKREAD		; HOOK HBIOS DISK READ SUPERVISOR
	LD	E,SCSI_CMD_READ		; SETUP READ COMMAND
	JP	SCSI_IO			; DO THE IO
;
;
;
SCSI_WRITE:
	CALL	HB_DSKWRITE		; HOOK HBIOS DISK WRITE SUPERVISOR
	LD	E,SCSI_CMD_WRITE	; SETUP WRITE COMMAND
	JP	SCSI_IO			; DO THE IO
;
;
;
SCSI_STATUS:
	LD	A,(IY+SCSI_STAT)	; GET STATUS OF SELECTED DEVICE
	OR	A			; SET FLAGS
	RET				; AND RETURN
;
;
;
SCSI_RESET:
	CALL	SCSI_INITDEV		; REINITIALIZE UNIT
	OR	A			; SET RESULT FLAGS
	RET
;
;
;
SCSI_DEVICE:
	LD	D,DIODEV_SCSI		; D := DEVICE TYPE
	LD	E,(IY+SCSI_DEV)		; E := PHYSICAL DEVICE NUMBER
	LD	C,%00110000		; C := GENERIC HARD DISK ATTRIBUTES
	LD	H,0			; H := MODE
	LD	L,(SCSI_IOBASE)		; L := BASE I/O ADDRESS
	XOR	A			; SIGNAL SUCCESS
	RET
;
;
;
SCSI_MEDIA:
	LD	A,E			; GET FLAGS
	OR	A			; SET FLAGS
	JR	Z,SCSI_MEDIA1		; JUST REPORT CURRENT STATUS AND MEDIA
	CALL	SCSI_INITDEV		; REINITIALIZE DEVICE
;
SCSI_MEDIA1:
	LD	A,(IY+SCSI_STAT)	; GET STATUS
	OR	A			; SET FLAGS
	LD	D,0			; NO MEDIA CHANGE DETECTED
	LD	E,MID_HD		; ASSUME WE ARE OK
	RET	Z			; RETURN IF GOOD INIT
	LD	E,MID_NONE		; SIGNAL NO MEDIA
	LD	A,ERR_NOMEDIA		; NO MEDIA ERROR
	OR	A			; SET FLAGS
	RET				; AND RETURN
;
;
;
SCSI_SEEK:
	BIT	7,D			; CHECK FOR LBA FLAG
	CALL	Z,HB_CHS2LBA		; CLEAR MEANS CHS, CONVERT TO LBA
	RES	7,D			; CLEAR FLAG REGARDLESS (DOES NO HARM IF ALREADY LBA)
	LD	(IY+SCSI_LBA+0),L	; SAVE NEW LBA
	LD	(IY+SCSI_LBA+1),H	; ...
	LD	(IY+SCSI_LBA+2),E	; ...
	LD	(IY+SCSI_LBA+3),D	; ...
	XOR	A			; SIGNAL SUCCESS
	RET				; AND RETURN
;
;
;
SCSI_CAP:
	LD	A,(IY+SCSI_STAT)	; GET STATUS
	PUSH	AF			; SAVE IT
	LD	A,SCSI_MEDCAP		; OFFSET TO CAPACITY FIELD
	CALL	LDHLIYA			; HL := IY + A, REG A TRASHED
	CALL	LD32			; GET THE CURRENT CAPACITY INTO DE:HL
	LD	BC,512			; 512 BYTES PER BLOCK
	POP	AF			; RECOVER STATUS
	OR	A			; SET FLAGS
	RET
;
;
;
SCSI_GEOM:
	; FOR LBA, WE SIMULATE CHS ACCESS USING 16 HEADS AND 16 SECTORS
	; RETURN HS:CC -> DE:HL, SET HIGH BIT OF D TO INDICATE LBA CAPABLE
	CALL	SCSI_CAP		; GET TOTAL BLOCKS IN DE:HL, BLOCK SIZE TO BC
	LD	L,H			; DIVIDE BY 256 FOR # TRACKS
	LD	H,E			; ... HIGH BYTE DISCARDED, RESULT IN HL
	LD	D,16 | $80		; HEADS / CYL = 16, SET LBA CAPABILITY BIT
	LD	E,16			; SECTORS / TRACK = 16
	RET				; DONE, A STILL HAS SCSI_CAP STATUS
;
;=============================================================================
; FUNCTION SUPPORT ROUTINES
;=============================================================================
;
; ON RETURN, ZF SET INDICATES HARDWARE FOUND
;
SCSI_DETECT:
	LD	C,SCSIBASE+3
	LD	A,$05
	OUT	(C),A
	NOP
	IN	A,(C)
	CP	$05
	RET	NZ
	LD	A,$0A
	OUT	(C),A
	NOP
	IN	A,(C)
	CP	$0A
	RET
;
; INITIALIZE DEVICE
;
SCSI_INITDEV:
	; INQUIRY COMMAND TO DETERMINE IF DEVICE EXISTS
	LD	HL,HB_WRKBUF		; BUFFER FOR INQUIRY DATA
	CALL	SCSI_INQUIRY		; RUN THE COMMAND
	JP	NZ,SCSI_NOMEDIA		; CONVERT FAILURE TO NO MEDIA
;
	; GET DEVICE CAPACITY
	CALL	SCSI_CAPACITY
	RET	NZ
;
	XOR	A
	LD	(IY+SCSI_STAT),A
	RET
;
;
;
SCSI_IO:
;
#IF (ESPSDTRACE == 1)
	PUSH	HL
	LD	HL,SCSI_PRTERR		; SET UP ESPSD_PRTERR
	EX	(SP),HL			; ... TO FILTER ALL EXITS
#ENDIF
;
	LD	(SCSI_DSKBUF),HL	; SAVE DISK BUFFER ADDRESS
	PUSH	DE			; SAVE COMMAND BYTE
	PUSH	HL			; SAVE BUFFER ADDRESS
	CALL	SCSI_CHKERR		; CHECK FOR ERR STATUS AND RESET IF SO
	POP	HL			; RESTORE BUFFER ADDRESS
	POP	DE			; RESTORE COMMAND BYTE
	RET	NZ			; BAIL OUT ON ERROR
;
	; SETUP SCSI COMMAND
	LD	A,E
	LD	(SCSI_S_CDB),A		; SET SCSI COMMAND
	; SETUP DISK BUFFER POINTERS
	LD	(SCSI_BUF_OUT),HL	; INPUT BUFFER
	LD	(SCSI_BUF_IN),HL	; OUTPUT BUFFER
	; SETUP CDB
	LD	HL,SCSI_S_CDB		; SET HL TO R/W CBD
	LD	(SCSI_CUR_CDB),HL	; SAVE IN IOT
	; SETUP LUN/LBA
	LD	A,(IY+SCSI_LUN)		; PUT LUN IN ACCUM
	RRCA				; MOVE TO TOP 3 BITS
	RRCA				; ...
	RRCA				; ...
	LD	B,A			; SAVE IN B
	LD	A,(IY+SCSI_LBA+2)	; GET MSB OF LBA
	AND	%00011111		; CLEAR LUN BITS
	OR	B			; MERGE WITH LUN
	LD	(SCSI_CUR_LUN),A	; PUT IN CDB
	LD	A,(IY+SCSI_LBA+1)	; LBA MID
	LD	(SCSI_CUR_LBN),A	; PUT IN CDB
	LD	A,(IY+SCSI_LBA+0)	; LBA MID
	LD	(SCSI_CUR_LBN+1),A	; PUT IN CDB
	; DO THE SCSI TRANSACTION
	CALL	SCSI_GO			; DO THE SCSI TRANSACTION
	JR	NZ,SCSI_IO1		; IF ERROR, SKIP INCREMENT
	; INCREMENT LBA
	LD	A,SCSI_LBA		; LBA OFFSET
	CALL	LDHLIYA			; HL := IY + A, REG A TRASHED
	CALL	INC32HL			; INCREMENT THE VALUE
	; INCREMENT DMA
	LD	HL,SCSI_DSKBUF+1	; POINT TO MSB OF BUFFER ADR
	INC	(HL)			; BUMP DMA BY
	INC	(HL)			; ... 512 BYTES
	XOR	A			; SIGNAL SUCCESS
SCSI_IO1:
	LD	HL,(SCSI_DSKBUF)	; CURRENT DMA TO HL
	OR	A			; SET FLAGS
	RET	Z			; DONE IF NO ERROR
	LD	A,ERR_IO		; SIGNAL IO ERROR
	OR	A			; SET FLAGS
	RET				; AND DONE
;
; CHECK CURRENT DEVICE FOR ERROR STATUS AND ATTEMPT TO RECOVER
; VIA RESET IF DEVICE IS IN ERROR.
;
SCSI_CHKERR:
	LD	A,(IY+SCSI_STAT)	; GET STATUS
	OR	A			; SET FLAGS
	CALL	NZ,SCSI_RESET		; IF ERROR STATUS, RESET BUS
	RET
;
; ISSUE SCSI INQUIRY COMMAND
; ON INPUT, HL POINTS TO OUTPUT DATA BUFFER
;
SCSI_INQUIRY:
	; SETUP BUFFER POINTERS
	LD	(SCSI_BUF_OUT),HL	; INPUT BUFFER
	LD	(SCSI_BUF_IN),HL	; OUTPUT BUFFER
	; SETUP INQUIRY CDB
	LD	HL,SCSI_S_INQ		; SET HL TO INQ CBD
	LD	(SCSI_CUR_CDB),HL	; SAVE IN IOT
	; SETUP LUN
	LD	A,(IY+SCSI_LUN)		; PUT LUN IN ACCUM
	RRCA				; MOVE TO TOP 3 BITS
	RRCA				; ...
	RRCA				; ...
	LD	(SCSI_INQ_LUN),A	; PUT IN INQ CDB
	; DO THE SCSI TRANSACTION
	JP	SCSI_GO			; DO THE SCSI TRANSACTION
;
; ISSUE SCSI CAPACITY COMMAND AND CAPTURE
; RESULTS AS DEVICE CAPACITY
;
SCSI_CAPACITY:
	; SETUP BUFFER POINTERS
	LD	HL,SCSI_CAP_BUF
	LD	(SCSI_BUF_OUT),HL	; INPUT BUFFER
	LD	(SCSI_BUF_IN),HL	; OUTPUT BUFFER
	; SETUP READ CAPACITY CDB
	LD	HL,SCSI_S_CAP		; SET HL TO CAP CBD
	LD	(SCSI_CUR_CDB),HL	; SAVE IN IOT
	; SETUP LUN
	LD	A,(IY+SCSI_LUN)		; PUT LUN IN ACCUM
	RRCA				; MOVE TO TOP 3 BITS
	RRCA				; ...
	RRCA				; ...
	LD	(SCSI_CAP_LUN),A	; PUT IN INQ CDB
	; DO THE SCSI TRANSACTION
	CALL	SCSI_GO			; DO THE SCSI TRANSACTION
	RET	NZ			; ABORT ON ERROR
;
	; RETURNED LBA IS BIG ENDIAN.  CONVERT TO A STANDARD 32-BIT
	; INTEGER IN DE:HL
	LD	HL,SCSI_CAP_BUF		; HL POINTS TO START OF BUF
	LD	D,(HL)			; MSB
	INC	HL			; NEXT BYTE
	LD	E,(HL)
	PUSH	DE			; SAVE HIGH WORD
	INC	HL
	LD	D,(HL)
	INC	HL
	LD	E,(HL)			; LSB
	POP	HL			; RECOVER HIGH WORD
	EX	DE,HL			; AND SWAP
;
	; RETURNED CAPACITY IS THE *LAST* LBA.  WE WANT THE NUMBER OF
	; BLOCKS AVAILABLE, SO WE NEED TO INCREMENT THE RETURNED VALUE.
	CALL	INC32
;
	; COPY CAPACITY TO DEVICE CONFIG DATA FIELD
	PUSH	HL			; SAVE HL
	LD	A,SCSI_MEDCAP		; OFFSET OF MEDIA CAPACITY FIELD		
	CALL	LDHLIYA			; HL POINTS TO MEDIA CAPACITY FIELD
	PUSH	HL			; MOVE HL
	POP	BC			; ... TO BC
	POP	HL			; RECOVER HL
	CALL	ST32			; SAVE CAP TO CFG BLOCK
;
	XOR	A
	RET				; DONE
;
;=============================================================================
; COMMAND PROCESSING
;=============================================================================
;
; WRAPPER FOR HBIOS INVOCATION
;
SCSI_GO:
	PUSH	IX			; PRESERVE IX
	LD	IX,SCSI_S_IOT		; POINT TO IO TABLE
	CALL	SCSI_GO1		; RUN THE TRANSACTION
	POP	IX			; RESTORE IX
	AND	%00111110		; IGNORE RESERVED BITS OF STATUS
	JP	NZ,SCSI_IOERR		; HANDLE ERROR
	RET				; DONE
;
;-------------------------------------------------------------------------------
;DO SCSI TRANSACTION
;-------------------------------------------------------------------------------
;
SCSI_GO1:
	LD A,$FF	;PRESET ERROR STATUS
	LD L,(IX+4)	;POINT TO STATUS ADDRESS
	LD H,(IX+5)	;POINT TO STATUS ADDRESS
	LD (HL),A	;SET ERROR
;
	XOR A		;
	OUT (SCSI_SR_MR),A	;RESET CONTROL REG
	OUT (SCSI_SR_TCR),A	;CLEAR COMMAND REG.
	OUT (SCSI_SR_ICR),A	;
	LD A,(IX)	;GET TID
	BIT	7,A	;   TURN ON MY ID
	OUT (SCSI_SR_ODR),A	;SET TARGET ID
	LD A,$01	;DRIVE BUS
	OUT (SCSI_SR_ICR),A	;
	LD A,$05	;SET SEL AND DRIVE BUS
	OUT (SCSI_SR_ICR),A	;
;
;WAIT FOR SCSI BUSY
	LD BC,0		;INIT TIMEOUT
S_SWT:
	IN A,(SCSI_SR_CSBS)	;GET BUS STATUS
	AND SCSI_SM_BSY	;MASK TO BUSY BIT
	JR NZ,S_BSYA	;JMP IF BUSY ACTIVE
	NOP		;KILL A LITTLE TIME
	NOP
	NOP
	NOP
	DEC BC		;DEC TIMEOUT
	LD A,B		;TEST TIMEOUT=0
	OR C
	JR NZ,S_SWT	;JMP IF NO TIMEOUT
	XOR A		;CLEAR A
	OUT (SCSI_SR_ICR),A	;CLEAR SEL AND DATA
	JR S_EXIT	;ERROR EXIT
;
;BUSY IS ACTIVE
S_BSYA:
	XOR A		;CLEAR A
	OUT (SCSI_SR_ICR),A	;CLEAR SEL AND DATA

;-------------------------------------------------------------------------------
;
;TARGET IS SELECTED SO TEST BSY AND REQ
;THEN DECODE REQUESTED PHASE
;
;-------------------------------------------------------------------------------
PHASE:
	XOR A
	OUT (SCSI_SR_ICR),A	;RESET INITIATOR
;
S_WTREQ:
	IN A,(SCSI_SR_CSBS)	;GET BUS STATUS
	LD B,A		;SAVE COPY
	AND SCSI_SM_BSY	;MASK TO BUSY BIT
	JR NZ,S_WTRQ1	;STILL BUSY SO CONT.

;-------------------------------------------------------------------------------
;BUSY LOST SO EXIT
;-------------------------------------------------------------------------------
S_EXIT:
	LD L,(IX+4)	;GET STATUS POINTER
	LD H,(IX+5)	;GET STATUS POINTER
	LD A,(HL)
	RET		;BUSY LOST? WERE DONE
;
S_WTRQ1:
	LD A,B		;RECOVER STATUS
	AND SCSI_SM_REQ	;REQUEST ACTIVE?
	JR Z,S_WTREQ	;LOOP TILL REQUEST

;-------------------------------------------------------------------------------
;REQUEST IS ACTIVE SO SET 5380 TO REQUESTED PHASE
;-------------------------------------------------------------------------------
	LD A,B		;RECOVER BUS STATUS
	RR A		;SHIFT STATUS TO PHASE BITS
	RR A
	AND $07		;MASK TO PHASE BITS
	OUT (SCSI_SR_TCR),A	;SET PHASE
;
;JUMP TO PHASE HANDLER
;
	LD A,B		;RECOVER BUS STATUS 
	RR A
	AND $0E		;MASK TO PHASE BITS
	LD E,A		;
	LD D,0
	LD HL,PHTABL	;POINT TO TABLE
	ADD HL,DE	;OFFSET INTO TABLE
	LD E,(HL)	;GET EXECUTION ADDRESS
	INC HL
	LD D,(HL)
	PUSH DE
	RET		;EXECUTE PHASE

;-------------------------------------------------------------------------------
;PHASE TABLE
;-------------------------------------------------------------------------------
PHTABL:
	.WORD	PHASE0	;DATA OUT
	.WORD	PHASE1	;DATA IN
	.WORD	PHASE2	;CMD OUT
	.WORD	PHASE3	;STATUS IN
	.WORD	S_EXIT	;UNUSED
	.WORD	S_EXIT	;UNUSED
	.WORD	PHASE6	;MESSAGE OUT
	.WORD	PHASE7	;MESSAGE IN

;-------------------------------------------------------------------------------
;PHASE HANDLERS
;-------------------------------------------------------------------------------
;
;DATA OUT
PHASE0:
	LD L,(IX+6)	;GET POINTER
	LD H,(IX+7)
	JP S_WRIT	;WRITE BYTES
;
;DATA IN
PHASE1:
	LD L,(IX+8)	;GET POINTER
	LD H,(IX+9)
	JP S_READ	;READ BYTES
;
;CMD OUT
PHASE2:
	LD L,(IX+2)
	LD H,(IX+3)
	JP S_WRIT
;
;STATUS IN
PHASE3:
	LD L,(IX+4)
	LD H,(IX+5)
	JP S_READ
;
;MSG OUT
PHASE6:
	LD L,(IX+10)
	LD H,(IX+11)
	JP S_WRIT
;
;MSG IN
PHASE7:
	LD L,(IX+12)
	LD H,(IX+13)
	JP S_READ
;-------------------------------------------------------------------------------
;SCSI WRITE ROUTINE (SEND BYTES TO TARGET)
;BUS PHASE ALREADY SET. RETURN ON PHASE MISMATCH 
;-------------------------------------------------------------------------------
S_WRIT:
	LD A,1		;DRIVE SCSI DATA BUS
	OUT (SCSI_SR_ICR),A
;
;WAIT FOR REQ WHILE CHECKING BUSY
;
S_WWREQ:
        IN A,(SCSI_SR_CSBS)  ;GET CURRENT BUS STAT
        LD B,A          ;SAVE IT
        AND SCSI_SM_REQ      ;REQUEST ACTIVE?
        JR NZ,S_WNXT    ;
;
        LD A,B          ;RECOVER CURRENT BUS STAT
        AND SCSI_SM_BSY      ;STILL BUSY?
        JP NZ,S_WWREQ   ;LOOP IF STILL BUSY
        JP PHASE        ;
;
;REQUEST ACTIVE SO CHECK PHASE
;
S_WNXT:
        IN A,(SCSI_SR_BSR)   ;GET STATUS
        AND SCSI_SM_PHM      ;MASK TO PHASE MATCH
        JP Z,PHASE      ;JMP IF PHASE MISMATCH
;
;REQUEST ACTIVE AND PHASE MATCH SO SEND DATA
;
	LD A,(HL)	;GET BYTE
	OUT (SCSI_SR_ODR),A	;SEND DATA
	LD A,$11	;ACK + DRIVE BUS
	OUT (SCSI_SR_ICR),A	;SET ACK,DRIVE SCSI BUS
	INC HL		;ADVANCE BUF POINTER
;
;WAIT FOR REQUEST TO DROP
;
S_WNREQ:
	IN A,(SCSI_SR_CSBS)	;GET CURRENT STATUS
	AND SCSI_SM_REQ
	JR NZ,S_WNREQ	;LOOP TILL REQ DROPS
;
	LD A,$1		;DROP ACK,ASSERT DATA
	OUT (SCSI_SR_ICR),A	;DROP ACK
	JP S_WWREQ	;LOOP FOR NEXT BYTE/PHASE
;-------------------------------------------------------------------------------
;SCSI READ ROUTINE (GET BYTES FROM TARGET)
;BUS PHASE ALREADY SET. RETURN ON PHASE MISMATCH 
;-------------------------------------------------------------------------------
;
S_READ:
;
;WAIT FOR REQ WHILE CHECKING BUSY
;
S_RWREQ:
        IN A,(SCSI_SR_CSBS)  ;GET CURRENT BUS STAT
        LD B,A          ;SAVE IT
        AND SCSI_SM_REQ      ;REQUEST ACTIVE?
        JR NZ,S_RNXT    ;
;
        LD A,B          ;RECOVER CURRENT BUS STAT
        AND SCSI_SM_BSY      ;STILL BUSY?
        JP NZ,S_RWREQ   ;LOOP IF STIL BUSY
        JP PHASE        ;
;
;REQUEST ACTIVE SO CHECK PHASE
S_RNXT:
        IN A,(SCSI_SR_BSR)   ;GET STATUS
        AND SCSI_SM_PHM      ;MASK TO PHASE MATCH
        JP Z,PHASE      ;JMP IF PHASE MISMATCH

;REQUEST ACTIVE AND PHASE MATCH SO GET DATA
;
	IN A, (SCSI_SR_CSD)	;GET DATA
	LD (HL),A	;SAVE DATA
	LD A,$10
	OUT (SCSI_SR_ICR),A	;SET ACK
	INC HL		;ADVANCE BUF POINTER
;
;WAIT FOR REQUEST TO DROP
;
S_RNREQ:
	IN A,(SCSI_SR_CSBS)	;GET CURRENT STATUS
	AND SCSI_SM_REQ
	JR NZ,S_RNREQ	;LOOP TILL REQ DROPS
	XOR A
	OUT (SCSI_SR_ICR),A	;DROP ACK
	JP S_READ	;LOOP FOR NEXT BYTE/PHASE

;
;=============================================================================
; HARDWARE INTERFACE ROUTINES
;=============================================================================
;
;=============================================================================
; ERROR HANDLING AND DIAGNOSTICS
;=============================================================================
;
; ERROR HANDLERS
;
SCSI_NOMEDIA:
	LD	A,SCSI_STNOMEDIA
	JR	SCSI_ERR
;
SCSI_IOERR:
	LD	A,SCSI_STIOERR
	JR	SCSI_ERR
;
SCSI_TO:
	LD	A,SCSI_STTO
	JR	SCSI_ERR
;
SCSI_NOTRDY:
	LD	A,SCSI_STNOTRDY
	JR	SCSI_ERR
;
SCSI_ERR:
	LD	(IY+SCSI_STAT),A	; SAVE NEW STATUS
;
#IF (SCSITRACE >= 2)
	CALL	SCSI_PRTSTAT
#ENDIF
	OR	A			; SET FLAGS
	RET
;
;
;
SCSI_PRTERR:
	RET	Z			; DONE IF NO ERRORS
	; FALL THRU TO SCSI_PRTSTAT
;
; PRINT FULL DEVICE STATUS LINE
;
SCSI_PRTSTAT:
	PUSH	AF
	PUSH	DE
	PUSH	HL
	LD	A,(IY+SCSI_STAT)
	CALL	SCSI_PRTPREFIX		; PRINT UNIT PREFIX
	JR	SCSI_PRTSTAT3
SCSI_PRTSTAT2:
	CALL	NEWLINE
	PRTS("SCSI:$")			; NO UNIT NUM IN PREFIX FOR INVALID UNIT
SCSI_PRTSTAT3:
	CALL	SCSI_PRTSTATSTR
	POP	HL
	POP	DE
	POP	AF
	RET
;
; PRINT STATUS STRING
;
SCSI_PRTSTATSTR:
	PUSH	AF
	PUSH	DE
	LD	A,(IY+SCSI_STAT)
	OR	A
	LD	DE,SCSI_STR_STOK
	JR	Z,SCSI_PRTSTATSTR1
	INC	A
	LD	DE,SCSI_STR_STNOMEDIA
	JR	Z,SCSI_PRTSTATSTR1
	INC	A
	LD	DE,SCSI_STR_STIOERR
	JR	Z,SCSI_PRTSTATSTR1
	INC	A
	LD	DE,SCSI_STR_STTO
	JR	Z,SCSI_PRTSTATSTR1
	INC	A
	LD	DE,SCSI_STR_STNOTRDY
	JR	Z,SCSI_PRTSTATSTR1
	LD	DE,SCSI_STR_STUNK
SCSI_PRTSTATSTR1:
	CALL	PC_SPACE		; FORMATTING
	CALL	WRITESTR
	POP	DE
	POP	AF
	RET
;
; PRINT DIAGNONSTIC PREFIX
;
SCSI_PRTPREFIX:	
	PUSH	AF
	CALL	NEWLINE
	PRTS("SCSI$")
	LD	A,(IY+SCSI_DEV)		; GET CURRENT DEVICE NUM
	CP	$FE			; NOT YET ASSIGNED?
	JR	Z,SCSI_PRTPREFIX1	; SKIP DEV NUM IF SO
	CALL	PRTDECB
SCSI_PRTPREFIX1:
	CALL	PC_COLON
	POP	AF
	RET
;
;=============================================================================
; STRING DATA
;=============================================================================
;
SCSI_STR_STOK		.TEXT	"OK$"
SCSI_STR_STNOMEDIA	.TEXT	"NO MEDIA$"
SCSI_STR_STIOERR	.TEXT	"IO ERROR$"
SCSI_STR_STTO		.TEXT	"TIMEOUT$"
SCSI_STR_STNOTRDY	.TEXT	"NOT READY$"
SCSI_STR_STUNK		.TEXT	"UNKNOWN ERROR$"
;
;=============================================================================
; DATA STORAGE
;=============================================================================
;
SCSI_DEVNUM	.DB	0		; TEMP DEVICE NUM USED DURING INIT
SCSI_DSKBUF	.DW	0		; ACTIVE DISK BUFFER
;
;----------------------------------------------------------------
;SCSI COMMAND DESCRIPTOR FOR READ/WRITE
;
SCSI_S_CDB:	
		.DB	SCSI_CMD_READ	; COMMAND
SCSI_CUR_LUN	.DB	0 << 5		; LUN/LBA HI
SCSI_CUR_LBN	.DB	0		; LBA MID
		.DB	0		; LBA LOW
		.DB	1		; COUNT
		.DB	0		; CONTROL
;
;----------------------------------------------------------------
;SCSI COMMAND DESCRIPTOR FOR INQUIRY
;
SCSI_S_INQ:	
		.DB	SCSI_CMD_INQ	; COMMAND
SCSI_INQ_LUN	.DB	0 << 5		; LUN (TOP 3 BITS)
		.DB	0		; PAGE CODE (UNUSED)
		.DB	0		; RESERVED
		.DB	$FF		; ALLOCATION LENGTH
		.DB	0		; CONTROL
;
;----------------------------------------------------------------
;SCSI COMMAND DESCRIPTOR FOR READ CAPACITY
;
SCSI_S_CAP:	
		.DB	SCSI_CMD_RDCAP	; COMMAND
SCSI_CAP_LUN	.DB	0 << 5		; LUN (TOP 3 BITS)
		.FILL	4,0		; LBA (UNUSED)
		.FILL	3,0		; RESERVED
		.DB	0		; CONTROL
;
;----------------------------------------------------------------
;SCSI I/O ADDRESS TABLE	FOR READ/WRITE
;DONT MESS WITH THIS EITHER
SCSI_S_IOT:
SCSI_CUR_TID	.DB	1 << SCSI_TID	; TARGET
		.DB	0		; UNUSED
SCSI_CUR_CDB	.DW	SCSI_S_CDB	; CDB POINTER
		.DW	SCSI_S_STAT	; STATUS POINTER
SCSI_BUF_OUT	.DW	HB_WRKBUF	; DATA OUT POINTER
SCSI_BUF_IN	.DW	HB_WRKBUF	; DATA IN POINTER
		.DW	SCSI_S_MSG	; MSG OUT POINTER
		.DW	SCSI_S_MSG	; MSG IN POINTER
;
SCSI_S_STAT	.DW	0		; SCSI ENDING STATUS
SCSI_S_MSG	.DW	0		; SCSI MESSAGE
;
SCSI_CAP_BUF	.FILL	8,0		; SCSI CAPACITY DATA BUFFER
;
;--------------------------------------------------------------------------------------------------
;   HBIOS MODULE TRAILER
;--------------------------------------------------------------------------------------------------
;
END_SCSI	.EQU	$
SIZ_SCSI	.EQU	END_SCSI - ORG_SCSI
;	
	MEMECHO	"SCSI occupies "
	MEMECHO	SIZ_SCSI
	MEMECHO	" bytes.\n"