aic79xx.seq

一个2.4.21版本的嵌入式linux内核

	bmov	ALLOCFIFO_SCBPTR, SCBPTR, 2;
	call	allocate_fifo;
	/* See if the host wants to send a message upon reconnection */
	test	SCB_CONTROL, MK_MESSAGE jz mesgin_done;
	mvi	HOST_MSG	call mk_mesg;
	jmp	mesgin_done;

not_found:
	SET_SEQINTCODE(NO_MATCH)
	jmp	mesgin_done;

not_found_ITloop:
	SET_SEQINTCODE(NO_MATCH)
	jmp	ITloop;

/*
 * We received a "command complete" message.  Put the SCB on the complete
 * queue and trigger a completion interrupt via the idle loop.  Before doing
 * so, check to see if there
 * is a residual or the status byte is something other than STATUS_GOOD (0).
 * In either of these conditions, we upload the SCB back to the host so it can
 * process this information.  In the case of a non zero status byte, we 
 * additionally interrupt the kernel driver synchronously, allowing it to
 * decide if sense should be retrieved.  If the kernel driver wishes to request
 * sense, it will fill the kernel SCB with a request sense command, requeue
 * it to the QINFIFO and tell us not to post to the QOUTFIFO by setting 
 * RETURN_1 to SEND_SENSE.
 */
mesgin_complete:

	/*
	 * If ATN is raised, we still want to give the target a message.
	 * Perhaps there was a parity error on this last message byte.
	 * Either way, the target should take us to message out phase
	 * and then attempt to complete the command again.  We should use a
	 * critical section here to guard against a timeout triggering
	 * for this command and setting ATN while we are still processing
	 * the completion.
	test	SCSISIGI, ATNI jnz mesgin_done;
	 */

	/*
	 * If we are identified and have successfully sent the CDB,
	 * any status will do.  Optimize this fast path.
	 */
	test	SCB_CONTROL, STATUS_RCVD jz mesgin_proto_violation;
	test	SEQ_FLAGS, NOT_IDENTIFIED|NO_CDB_SENT jz complete_accepted;

	/*
	 * If the target never sent an identify message but instead went
	 * to mesgin to give an invalid message, let the host abort us.
	 */
	test	SEQ_FLAGS, NOT_IDENTIFIED jnz mesgin_proto_violation;

	/*
	 * If we recevied good status but never successfully sent the
	 * cdb, abort the command.
	 */
	test	SCB_SCSI_STATUS,0xff	jnz complete_accepted;
	test	SEQ_FLAGS, NO_CDB_SENT jnz mesgin_proto_violation;
complete_accepted:

	/*
	 * See if we attempted to deliver a message but the target ingnored us.
	 */
	test	SCB_CONTROL, MK_MESSAGE jz complete_nomsg;
	SET_SEQINTCODE(MKMSG_FAILED)
complete_nomsg:
	call	queue_scb_completion;
	jmp	await_busfree;

freeze_queue:
	/* Cancel any pending select-out. */
	test	SSTAT0, SELDO|SELINGO jnz . + 2;
	and	SCSISEQ0, ~ENSELO;
	mov	ACCUM_SAVE, A;
	clr	A;
	add	QFREEZE_COUNT, 1;
	adc	QFREEZE_COUNT[1], A;
	or	SEQ_FLAGS2, SELECTOUT_QFROZEN;
	mov	A, ACCUM_SAVE ret;

queue_arg1_scb_completion:
	SET_MODE(M_SCSI, M_SCSI)
	bmov	SCBPTR, ARG_1, 2;
queue_scb_completion:
	if ((ahd->bugs & AHD_ABORT_LQI_BUG) == 0) {
		/*
		 * Set MK_MESSAGE to trigger an abort should this SCB
		 * be referenced by a target even though it is not currently
		 * active.
		 */
		or	SCB_CONTROL, MK_MESSAGE;
	}
	test	SCB_SCSI_STATUS,0xff	jnz bad_status;
	/*
	 * Check for residuals
	 */
	test	SCB_SGPTR, SG_LIST_NULL jnz complete;	/* No xfer */
	test	SCB_SGPTR, SG_FULL_RESID jnz upload_scb;/* Never xfered */
	test	SCB_RESIDUAL_SGPTR, SG_LIST_NULL jz upload_scb;
complete:
	bmov	SCB_NEXT_COMPLETE, COMPLETE_SCB_HEAD, 2;
	bmov	COMPLETE_SCB_HEAD, SCBPTR, 2 ret;
bad_status:
	cmp	SCB_SCSI_STATUS, STATUS_PKT_SENSE je upload_scb;
	call	freeze_queue;
upload_scb:
	bmov	SCB_NEXT_COMPLETE, COMPLETE_DMA_SCB_HEAD, 2;
	bmov	COMPLETE_DMA_SCB_HEAD, SCBPTR, 2;
	or	SCB_SGPTR, SG_STATUS_VALID ret;

/*
 * Is it a disconnect message?  Set a flag in the SCB to remind us
 * and await the bus going free.  If this is an untagged transaction
 * store the SCB id for it in our untagged target table for lookup on
 * a reselction.
 */
mesgin_disconnect:
	/*
	 * If ATN is raised, we still want to give the target a message.
	 * Perhaps there was a parity error on this last message byte
	 * or we want to abort this command.  Either way, the target
	 * should take us to message out phase and then attempt to
	 * disconnect again.
	 * XXX - Wait for more testing.
	test	SCSISIGI, ATNI jnz mesgin_done;
	 */
	test	SEQ_FLAGS, NOT_IDENTIFIED|NO_CDB_SENT
		jnz mesgin_proto_violation;
	or	SCB_CONTROL,DISCONNECTED;
	test	SCB_CONTROL, TAG_ENB jnz await_busfree;
queue_disc_scb:
	bmov	REG0, SCBPTR, 2;
	INDEX_DISC_LIST(SAVED_SCSIID, SAVED_LUN);
	bmov	DINDEX, SINDEX, 2;
	bmov	DINDIR, REG0, 2;
	bmov	SCBPTR, REG0, 2;
	/* FALLTHROUGH */
await_busfree:
	and	SIMODE1, ~ENBUSFREE;
	if ((ahd->bugs & AHD_BUSFREEREV_BUG) == 0) {
		/*
		 * In the BUSFREEREV_BUG case, the
		 * busfree status was cleared at the
		 * beginning of the connection.
		 */
		mvi	CLRSINT1,CLRBUSFREE;
	}
	mov	NONE, SCSIDAT;		/* Ack the last byte */
	test	MODE_PTR, ~(MK_MODE(M_DFF1, M_DFF1))
		jnz await_busfree_not_m_dff;
SET_SRC_MODE	M_DFF1;
SET_DST_MODE	M_DFF1;
await_busfree_clrchn:
	mvi	DFFSXFRCTL, CLRCHN;
await_busfree_not_m_dff:
	call	clear_target_state;
	test	SSTAT1,REQINIT|BUSFREE	jz .;
	test	SSTAT1, BUSFREE jnz idle_loop;
	SET_SEQINTCODE(MISSED_BUSFREE)


/*
 * Save data pointers message:
 * Copying RAM values back to SCB, for Save Data Pointers message, but
 * only if we've actually been into a data phase to change them.  This
 * protects against bogus data in scratch ram and the residual counts
 * since they are only initialized when we go into data_in or data_out.
 * Ack the message as soon as possible.
 */
SET_SRC_MODE	M_DFF1;
SET_DST_MODE	M_DFF1;
mesgin_sdptrs:
	mov	NONE,SCSIDAT;		/*dummy read from latch to ACK*/
	test	SEQ_FLAGS, DPHASE	jz ITloop;
	call	save_pointers;
	jmp	ITloop;

save_pointers:
	/*
	 * If we are asked to save our position at the end of the
	 * transfer, just mark us at the end rather than perform a
	 * full save.
	 */
	test	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL jz save_pointers_full;
	or	SCB_SGPTR, SG_LIST_NULL ret;

save_pointers_full:
	/*
	 * The SCB_DATAPTR becomes the current SHADDR.
	 * All other information comes directly from our residual
	 * state.
	 */
	bmov	SCB_DATAPTR, SHADDR, 8;
	bmov	SCB_DATACNT, SCB_RESIDUAL_DATACNT, 8 ret;

/*
 * Restore pointers message?  Data pointers are recopied from the
 * SCB anytime we enter a data phase for the first time, so all
 * we need to do is clear the DPHASE flag and let the data phase
 * code do the rest.  We also reset/reallocate the FIFO to make
 * sure we have a clean start for the next data or command phase.
 */
mesgin_rdptrs:
	and	SEQ_FLAGS, ~DPHASE;
	test	MODE_PTR, ~(MK_MODE(M_DFF1, M_DFF1)) jnz msgin_rdptrs_get_fifo;
	mvi	DFFSXFRCTL, RSTCHN|CLRSHCNT;
	SET_MODE(M_SCSI, M_SCSI)
msgin_rdptrs_get_fifo:
	call	allocate_fifo;
	jmp	mesgin_done;

clear_target_state:
	mvi	LASTPHASE, P_BUSFREE;
	/* clear target specific flags */
	mvi	SEQ_FLAGS, NOT_IDENTIFIED|NO_CDB_SENT ret;

phase_lock:     
	test	SCSIPHASE, 0xFF jz .;
	test	SSTAT1, SCSIPERR jnz phase_lock;
phase_lock_latch_phase:
	and	LASTPHASE, PHASE_MASK, SCSISIGI ret;

/*
 * Functions to read data in Automatic PIO mode.
 *
 * An ACK is not sent on input from the target until SCSIDATL is read from.
 * So we wait until SCSIDATL is latched (the usual way), then read the data
 * byte directly off the bus using SCSIBUSL.  When we have pulled the ATN
 * line, or we just want to acknowledge the byte, then we do a dummy read
 * from SCISDATL.  The SCSI spec guarantees that the target will hold the
 * data byte on the bus until we send our ACK.
 *
 * The assumption here is that these are called in a particular sequence,
 * and that REQ is already set when inb_first is called.  inb_{first,next}
 * use the same calling convention as inb.
 */
inb_next:
	mov	NONE,SCSIDAT;		/*dummy read from latch to ACK*/
inb_next_wait:
	/*
	 * If there is a parity error, wait for the kernel to
	 * see the interrupt and prepare our message response
	 * before continuing.
	 */
	test	SCSIPHASE, 0xFF jz .;
	test	SSTAT1, SCSIPERR jnz inb_next_wait;
inb_next_check_phase:
	and	LASTPHASE, PHASE_MASK, SCSISIGI;
	cmp	LASTPHASE, P_MESGIN jne mesgin_phasemis;
inb_first:
	clr	DINDEX[1];
	mov	DINDEX,SINDEX;
	mov	DINDIR,SCSIBUS	ret;		/*read byte directly from bus*/
inb_last:
	mov	NONE,SCSIDAT ret;		/*dummy read from latch to ACK*/

mk_mesg:
	mvi	SCSISIGO, ATNO;
	mov	MSG_OUT,SINDEX ret;

SET_SRC_MODE	M_DFF1;
SET_DST_MODE	M_DFF1;
disable_ccsgen:
	test	SG_STATE, FETCH_INPROG jz disable_ccsgen_fetch_done;
	clr	CCSGCTL;
disable_ccsgen_fetch_done:
	clr	SG_STATE ret;

service_fifo:
	/*
	 * Do we have any prefetch left???
	 */
	test	SG_STATE, SEGS_AVAIL jnz idle_sg_avail;

	/*
	 * Can this FIFO have access to the S/G cache yet?
	 */
	test	CCSGCTL, SG_CACHE_AVAIL jz return;

	/* Did we just finish fetching segs? */
	test	CCSGCTL, CCSGDONE jnz idle_sgfetch_complete;

	/* Are we actively fetching segments? */
	test	CCSGCTL, CCSGENACK jnz return;

	/*
	 * We fetch a "cacheline aligned" and sized amount of data
	 * so we don't end up referencing a non-existant page.
	 * Cacheline aligned is in quotes because the kernel will
	 * set the prefetch amount to a reasonable level if the
	 * cacheline size is unknown.
	 */
	bmov	SGHADDR, SCB_RESIDUAL_SGPTR, 4;
	mvi	SGHCNT, SG_PREFETCH_CNT;
	if ((ahd->bugs & AHD_REG_SLOW_SETTLE_BUG) != 0) {
		/*
		 * Need two instruction between "touches" of SGHADDR.
		 */
		nop;
	}
	and	SGHADDR[0], SG_PREFETCH_ALIGN_MASK, SCB_RESIDUAL_SGPTR;
	mvi	CCSGCTL, CCSGEN|SG_CACHE_AVAIL|CCSGRESET;
	or	SG_STATE, FETCH_INPROG ret;
idle_sgfetch_complete:
	/*
	 * Guard against SG_CACHE_AVAIL activating during sg fetch
	 * request in the other FIFO.
	 */
	test	SG_STATE, FETCH_INPROG jz return;
	clr	CCSGCTL;
	and	CCSGADDR, SG_PREFETCH_ADDR_MASK, SCB_RESIDUAL_SGPTR;
	mvi	SG_STATE, SEGS_AVAIL|LOADING_NEEDED;
idle_sg_avail:
	/* Does the hardware have space for another SG entry? */
	test	DFSTATUS, PRELOAD_AVAIL jz return;
	if ((ahd->flags & AHD_64BIT_ADDRESSING) != 0) {
		bmov	HADDR, CCSGRAM, 8;
	} else {
		bmov 	HADDR, CCSGRAM, 4;
	}
	bmov	HCNT, CCSGRAM, 3;
	test	HCNT[0], 0x1 jz . + 2;
	xor	DATA_COUNT_ODD, 0x1;
	bmov	SCB_RESIDUAL_DATACNT[3], CCSGRAM, 1;
	if ((ahd->flags & AHD_39BIT_ADDRESSING) != 0) {
		and	HADDR[4], SG_HIGH_ADDR_BITS, SCB_RESIDUAL_DATACNT[3];
	}
	if ((ahd->flags & AHD_64BIT_ADDRESSING) != 0) {
		/* Skip 4 bytes of pad. */
		add	CCSGADDR, 4;
	}
sg_advance:
	clr	A;			/* add sizeof(struct scatter) */
	add	SCB_RESIDUAL_SGPTR[0],SG_SIZEOF;
	adc	SCB_RESIDUAL_SGPTR[1],A;
	adc	SCB_RESIDUAL_SGPTR[2],A;
	adc	SCB_RESIDUAL_SGPTR[3],A;
	mov	SINDEX, SCB_RESIDUAL_SGPTR[0];
	test	DATA_COUNT_ODD, 0x1 jz . + 2;
	or	SINDEX, ODD_SEG;
	test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jz . + 3;
	or	SINDEX, LAST_SEG;
	clr	SG_STATE;
	mov	SG_CACHE_PRE, SINDEX;
	/*
	 * Load the segment.  Or in HDMAEN here too
	 * just in case HDMAENACK has not come true
	 * by the time this segment is loaded.  If
	 * HDMAENACK is not true, this or will disable
	 * HDMAEN mid-transfer.  We do not want to simply
	 * mvi our original settings as SCSIEN automatically
	 * de-asserts and we don't want to accidentally
	 * re-enable it.
	 */
	if ((ahd->features & AHD_NEW_DFCNTRL_OPTS) != 0) {
		/*
		 * Use SCSIENWRDIS so that SCSIEN is never
		 * modified by this operation.
		 */
		or	DFCNTRL, PRELOADEN|SCSIENWRDIS|HDMAEN;
	} else {
		or	DFCNTRL, PRELOADEN|HDMAEN;
	}
	/*
	 * Do we have another segment in the cache?
	 */
	add	NONE, SG_PREFETCH_CNT_LIMIT, CCSGADDR;
	jnc	return;
	and	SG_STATE, ~SEGS_AVAIL ret;

/*
 * Initialize the DMA address and counter from the SCB.
 */
load_first_seg:
	bmov	HADDR, SCB_DATAPTR, 11;
	and	DATA_COUNT_ODD, 0x1, SCB_DATACNT[0];
	and	REG_ISR, ~SG_FULL_RESID, SCB_SGPTR[0];
	test	SCB_DATACNT[3], SG_LAST_SEG jz . + 2;
	or	REG_ISR, LAST_SEG;
	test	DATA_COUNT_ODD, 0x1 jz . + 2;
	or	REG_ISR, ODD_SEG;
	mov	SG_CACHE_PRE, REG_ISR;
	mvi	DFCNTRL, (PRELOADEN|SCSIEN|HDMAEN);
	/*
	 * Since we've are entering a data phase, we will
	 * rely on the SCB_RESID* fields.  Initialize the
	 * residual and clear the full residual flag.
	 */
	and	SCB_SGPTR[0], ~SG_FULL_RESID;
	bmov	SCB_RESIDUAL_DATACNT[3], SCB_DATACNT[3], 5;
	/* If we need more S/G elements, tell the idle loop */
	test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jnz . + 2;
	mvi	SG_STATE, LOADING_NEEDED ret;
	clr	SG_STATE ret;

p_data_handle_xfer:
	call	setjmp_setscb;
	test	SG_STATE, LOADING_NEEDED jnz service_fifo;
p_data_clear_handler:
	or	LONGJMP_ADDR[1], INVALID_ADDR ret;

p_data:
	test	SEQ_FLAGS, NOT_IDENTIFIED|NO_CDB_SENT	jz p_data_allowed;
	SET_SEQINTCODE(PROTO_VIOLATION)
p_data_allowed:
 
	test	SEQ_FLAGS, DPHASE	jz data_phase_initialize;

	/*
	 * If we re-enter the data phase after going through another
	 * phase, our transfer location has almost certainly been
	 * corrupted by the interveining, non-data, transfers.  Ask
	 * the host driver to fix us up based on the transfer residual
	 * unless we already know that we should be bitbucketing.
	 */
	test	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL jnz p_data_bitbucket;
	SET_SEQINTCODE(PDATA_REINIT)
	jmp	data_phase_inbounds;

p_data_bitbucket:
	/*
	 * Turn on `Bit Bucket' mode, wait until the target takes
	 * us to another phase, and then notify the host.
	 */
	mov	SAVED_MODE, MODE_PTR;
	test	MODE_PTR, ~(MK_MODE(M_DFF1, M_DFF1))
		jnz bitbucket_not_m_dff;
	/*
	 * Ensure that any FIFO contents are cleared out and the
	 * FIFO free'd prior to starting the BITBUCKET.  BITBUCKET
	 * doesn't discard data already in the FIFO.
	 */
	mvi	DFFSXFRCTL, RSTCHN|CLRSHCNT;
	SET_MODE(M_SCSI, M_SCSI)
bitbucket_not_m_dff:
	or	SXFRCTL1,BITBUCKET;
	/* Wait for non-data phase. */
	test	SCSIPHASE, ~DATA_PHASE_MASK jz .;
	and	SXFRCTL1, ~BITBUCKET;
	RESTORE_MODE(SAVED_MODE)
SET_SRC_MODE	M_DFF1;
SET_DST_MODE	M_DFF1;
	SET_SEQINTCODE(DATA_OVERRUN)
	jmp	ITloop;

data_phase_initialize:
	test	SCB_SGPTR[0], SG_LIST_NULL jnz p_data_bitbucket;
	call	load_first_seg;
data_phase_inbounds:
	/* We have seen a data phase at least once. */
	or	SEQ_FLAGS, DPHASE;
	mov	SAVED_MODE, MODE_PTR;
	test	SG_STATE, LOADING_NEEDED jz data_group_dma_loop;
	call	p_data_handle_xfer;
data_group_dma_loop:
	/*
	 * The transfer is complete if either the last segment
	 * completes or the target changes phase.  Both conditions
	 * will clear SCSIEN.
	 */
	call	idle_loop_service_fifos;
	call	idle_loop_cchan;
	call	idle_loop_gsfifo;
	RESTORE_MODE(SAVED_MODE)
	test	DFCNTRL, SCSIEN jnz data_group_dma_loop;

data_group_dmafinish:
	/*
	 * The transfer has terminated either due to a phase
	 * change, and/or the completion of the last segment.
	 * We have two goals here.  Do as much other work