mac-rom/Drivers/Sony/SonySWIM3GC.a

;_______________________________________________________________________
;
;	File:		SonySWIM3GC.a
;
;	Written by:	Monte Benaresh 1/4/94.
;
;	Copyright:	<09> 1994 by Apple Computer, Inc., all rights reserved.
;
;	Change History (most recent first):
;
;	   <SM2>	 1/31/94	LB		Changed SWIM3 register accesses to use the new address table in
;									SWIM3Vars.  See <SM22> comments in SonySWIM3.a.
;		 <1>	  1/4/94	LB		first checked in
;_______________________________________________________________________
;
;	Grand Central DMA routines for Sony SWIM3 driver
;
;	This file contains the hardware-specific routines for the Grand
;	Central DMA controller, used on Tsumani/TNT.  These routines are
;	installed into vectors which are called by the Sony SWIM3 floppy
;	driver.
;
;	To do:
;_______________________________________________________________________

			INCLUDE		'DBDMA.a'
			INCLUDE		'GrandCentralPriv.a'


			with	SWIM3Vars

;_______________________________________________________________________
;
;  Routine: 	jsr 	StartDMAAction
;  Inputs:		d0.l-	DMA timeout value
;				d1	-	drive#
;				a1	- 	Globals
;  Outputs: 	none
;  Destroys:	d0,a0
;  Calls:		none
;  Called by:	RawTrackRead, ReadRawHeader
;
;  Function:	This routine saves state in the DMARegSave area, and starts
;				the DMA, returning to the caller's caller.
;_______________________________________________________________________

jStartGCDMAAction
				movem.l	a3/d1-d3,DMARegSave(a1)		; save state
				move.l	(sp)+,DMACompletionPtr(a1)	; stuff the completion routine
				
				bsr.s	StartDMATimeout				; start a time-out for the DMA

;	enable floppy DMA channel interrupts

				_GCEnableInterruptSource	gcifDmaFloppy

				move.b 	#StartAction,([vOnes,a1])	; Start action
				
				moveq	#noErr,d0					; return to caller's caller with no error
				rts

;_______________________________________________________________________
;
;  Routine: 	jsr 	SetUpDMAXFer
;  Inputs:		a0	-	DMA transfer address
;				a1 	- 	SonyVars ptr
;				d0	-	bit 31 = 0	-> read
;						       = 1	-> write
;						bits 0-30	-> transfer count
;  Outputs:		none
;  Destroys:	d0
;  Calls:
;  Called by:
;
;  Function:	Sets up address, count, and direction for a DMA
;				transfer.
;_______________________________________________________________________

jSetUpGCDMAXfer
				movem.l	a2-a3/d1,-(sp)				; use a2 for DMA regs ptr, a3 for SonyVars

				move.l	a1,a3						; SonyVars

				move.l	a0,a1						; set xfer address
				move.l	DBDMADescPtr(a3),a0			; set ptr to descriptor
				swap	d0							; count in high word, bit 15 = command
				btst	#15,d0
				bne		@write
@read
				move.w	#INPUT_LAST,d0
				bra		@makeCCD
@write
				move.w	#OUTPUT_LAST,d0
@makeCCD
				swap	d0							; high word = cmd, low word = count
				_MakeCCDescriptor					; set up the descriptor


; Point the DMA hardware at our CCL

				movea.l	DMABaseAddr(a3),a0			; pointer to Grand Central reg base
				adda.l	#kGCDMAChannelRegisterSpace \
						+ gcChannelFloppy*$100,a0	; point to floppy channel registers

; Reset anything wrong with the channel status

				move.l	#	kdbdmaClrRun |\
							kdbdmaClrPause |\
							kdbdmaClrHalted |\
							kdbdmaClrDead, d0
				_SetChannelControl

				move.l	DBDMADescPtr(a3),d0			; pointer to channel command list in D0
				_SetCommandPtr						; A0 still points to DBDMAChannelRegisters

; Start our channel running

				move.l	#	kdbdmaSetRun |\
							kdbdmaClrPause |\
							kdbdmaClrHalted |\
							kdbdmaClrDead |\
							kdbdmaSetActive, d0
				_SetChannelControl					; A0 still points to DBDMAChannelRegisters

				move.l	a3,a1						;restore a1
				movem.l	(sp)+,a2-a3/d1
				rts

;_______________________________________________________________________
;
;  Routine: 	jsr 	ClearDMAInt
;  Inputs:		a1 	- 	SonyVars ptr
;  Outputs:		none
;  Destroys:	none
;  Calls:
;  Called by:
;
;  Function:	Clears floppy DMA controller interrupt.
;_______________________________________________________________________

jClearGCDMAInt
				move.l	a0,-(sp)

				_GCClearInterruptSource	gcifDmaFloppy		; clear the floppy DMA interrupt

				move.l	(sp)+,a0
				rts



;_______________________________________________________________________
;
;  Routine: 	jsr 	StopDMA
;  Inputs:		a1 	- 	SonyVars ptr
;  Outputs:		none
;  Destroys:	none
;  Calls:
;  Called by:
;
;  Function:	Stops the floppy DMA channel.
;_______________________________________________________________________

jStopGCDMA
				movem.l	a0/d0,-(sp)

;	clear the run bit in the Grand Central floppy DMA channel control register

				movea.l	DMABaseAddr(a1),a0			; pointer to Grand Central reg base
				adda.l	#kGCDMAChannelRegisterSpace \
						+ gcChannelFloppy*$100,a0	; point to floppy channel registers
				move.l	#kdbdmaClrRun, d0
				_SetChannelControl

				movem.l	(sp)+,d0/a0
				rts


			endwith		; SWIM3Vars