cy.c

早期freebsd实现

		 * This special check is because B_BUSY never
		 * gets cleared in the non-waiting rewind case.
		 */
		if (bp->b_repcnt == 0 && (bp->b_flags&B_DONE))
			break;
		bp->b_flags |= B_WANTED;
		sleep((caddr_t)bp, PRIBIO);
	}
	bp->b_flags = B_BUSY|B_READ;
	splx(s);
	bp->b_dev = dev;
	bp->b_repcnt = count;
	bp->b_command = com;
	bp->b_blkno = 0;
	cystrategy(bp);
	/*
	 * In case of rewind from close; don't wait.
	 * This is the only case where count can be 0.
	 */
	if (count == 0)
		return;
	biowait(bp);
	if (bp->b_flags&B_WANTED)
		wakeup((caddr_t)bp);
	bp->b_flags &= B_ERROR;
}

cystrategy(bp)
	register struct buf *bp;
{
	int ycunit = YCUNIT(bp->b_dev);
	register struct vba_ctlr *vm;
	register struct buf *dp;
	int s;

	/*
	 * Put transfer at end of unit queue.
	 */
	dlog((LOG_INFO, "cystrategy(%o, %x)\n", bp->b_dev, bp->b_command));
	dp = &ycutab[ycunit];
	bp->av_forw = NULL;
	vm = ycdinfo[ycunit]->ui_mi;
	/* BEGIN GROT */
	if (bp->b_flags & B_RAW) {
		if (bp->b_bcount >= CYMAXIO) {
			uprintf("cy%d: i/o size too large\n", vm->um_ctlr);
			bp->b_error = EINVAL;
			bp->b_resid = bp->b_bcount;
			bp->b_flags |= B_ERROR;
			biodone(bp);
			return;
		}
	}
	/* END GROT */
	s = spl3();
	if (dp->b_actf == NULL) {
		dp->b_actf = bp;
		/*
		 * Transport not already active...
		 * put at end of controller queue.
		 */
		 dp->b_forw = NULL;
		 if (vm->um_tab.b_actf == NULL)
			vm->um_tab.b_actf = dp;
		else
			vm->um_tab.b_actl->b_forw = dp;
	} else
		dp->b_actl->av_forw = bp;
	dp->b_actl = bp;
	/*
	 * If the controller is not busy, get it going.
	 */
	if (vm->um_tab.b_active == 0)
		cystart(vm);
	splx(s);
}

/*
 * Start activity on a cy controller.
 */
cystart(vm)
	register struct vba_ctlr *vm;
{
	register struct buf *bp, *dp;
	register struct yc_softc *yc;
	register struct cy_softc *cy;
	int ycunit;
	daddr_t blkno;

	dlog((LOG_INFO, "cystart()\n"));
	/*
	 * Look for an idle transport on the controller.
	 */
loop:
	if ((dp = vm->um_tab.b_actf) == NULL)
		return;
	if ((bp = dp->b_actf) == NULL) {
		vm->um_tab.b_actf = dp->b_forw;
		goto loop;
	}
	ycunit = YCUNIT(bp->b_dev);
	yc = &yc_softc[ycunit];
	cy = &cy_softc[CYUNIT(bp->b_dev)];
	/*
	 * Default is that last command was NOT a write command;
	 * if we do a write command we will notice this in cyintr().
	 */
	yc->yc_lastiow = 0;
	if (yc->yc_openf < 0 ||
	    (bp->b_command != CY_SENSE && (cy->cy_tpb.tpstatus&CYS_OL) == 0)) {
		/*
		 * Have had a hard error on a non-raw tape
		 * or the tape unit is now unavailable (e.g.
		 * taken off line).
		 */
		dlog((LOG_INFO, "openf %d command %x status %b\n",
		   yc->yc_openf, bp->b_command, cy->cy_tpb.tpstatus, CYS_BITS));
		bp->b_flags |= B_ERROR;
		goto next;
	}
	if (bp == &ccybuf[CYUNIT(bp->b_dev)]) {
		/*
		 * Execute control operation with the specified count.
		 *
		 * Set next state; give 5 minutes to complete
		 * rewind or file mark search, or 10 seconds per
		 * iteration (minimum 60 seconds and max 5 minutes)
		 * to complete other ops.
		 */
		if (bp->b_command == CY_REW) {
			vm->um_tab.b_active = SREW;
			yc->yc_timo = 5*60;
		} else if (bp->b_command == CY_FSF ||
		    bp->b_command == CY_BSF) {
			vm->um_tab.b_active = SCOM;
			yc->yc_timo = 5*60;
		} else {
			vm->um_tab.b_active = SCOM;
			yc->yc_timo = imin(imax(10*(int)bp->b_repcnt,60),5*60);
		}
		cy->cy_tpb.tprec = htoms(bp->b_repcnt);
		dlog((LOG_INFO, "bpcmd "));
		goto dobpcmd;
	}
	/*
	 * For raw I/O, save the current block
	 * number in case we have to retry.
	 */
	if (bp->b_flags & B_RAW) {
		if (vm->um_tab.b_errcnt == 0) {
			yc->yc_blkno = bp->b_blkno;
			yc->yc_nxrec = yc->yc_blkno + 1;
		}
	} else {
		/*
		 * Handle boundary cases for operation
		 * on non-raw tapes.
		 */
		if (bp->b_blkno > yc->yc_nxrec) {
			/*
			 * Can't read past known end-of-file.
			 */
			bp->b_flags |= B_ERROR;
			bp->b_error = ENXIO;
			goto next;
		}
		if (bp->b_blkno == yc->yc_nxrec && bp->b_flags&B_READ) {
			/*
			 * Reading at end of file returns 0 bytes.
			 */
			bp->b_resid = bp->b_bcount;
			clrbuf(bp);
			goto next;
		}
		if ((bp->b_flags&B_READ) == 0)
			/*
			 * Writing sets EOF.
			 */
			yc->yc_nxrec = bp->b_blkno + 1;
	}
	if ((blkno = yc->yc_blkno) == bp->b_blkno) {
		caddr_t addr;
		int cmd;

		/*
		 * Choose the appropriate i/o command based on the
		 * transfer size, the estimated block size,
		 * and the controller's internal buffer size.
		 * If the request length is longer than the tape
		 * block length, a buffered read will fail,
		 * thus, we request at most the size that we expect.
		 * We then check for larger records when the read completes.
		 * If we're retrying a read on a raw device because
		 * the original try was a buffer request which failed
		 * due to a record length error, then we force the use
		 * of the raw controller read (YECH!!!!).
		 */
		if (bp->b_flags&B_READ) {
			if (yc->yc_blksize <= cy->cy_bs &&
			    vm->um_tab.b_errcnt == 0)
				cmd = CY_BRCOM;
			else
				cmd = CY_RCOM;
		} else {
			/*
			 * On write error retries erase the
			 * inter-record gap before rewriting.
			 */
			if (vm->um_tab.b_errcnt &&
			    vm->um_tab.b_active != SERASED) {
				vm->um_tab.b_active = SERASE;
				bp->b_command = CY_ERASE;
				yc->yc_timo = 60;
				goto dobpcmd;
			}
			cmd = (bp->b_bcount > cy->cy_bs) ? CY_WCOM : CY_BWCOM;
		}
		vm->um_tab.b_active = SIO;
		addr = (caddr_t)vbasetup(bp, &cy->cy_rbuf, 1);
		cy->cy_tpb.tpcmd = cmd;
		cy->cy_tpb.tpcontrol = yc->yc_dens;
		if (cmd == CY_RCOM || cmd == CY_WCOM)
			cy->cy_tpb.tpcontrol |= CYCW_LOCK;
		cy->cy_tpb.tpstatus = 0;
		cy->cy_tpb.tpcount = 0;
		cyldmba(cy->cy_tpb.tpdata, (caddr_t)addr);
		cy->cy_tpb.tprec = 0;
		if (cmd == CY_BRCOM)
			cy->cy_tpb.tpsize = htoms(imin(yc->yc_blksize,
			    (int)bp->b_bcount));
		else
			cy->cy_tpb.tpsize = htoms(bp->b_bcount);
		cyldmba(cy->cy_tpb.tplink, (caddr_t)0);
		do
			uncache(&cy->cy_ccb.cbgate);
		while (cy->cy_ccb.cbgate == GATE_CLOSED);
		cyldmba(cy->cy_ccb.cbtpb, (caddr_t)&cy->cy_tpb);
		cy->cy_ccb.cbcw = CBCW_IE;
		cy->cy_ccb.cbgate = GATE_CLOSED;
		dlog((LOG_INFO, "CY_GO(%x) cmd %x control %x size %d\n",
		    vm->um_addr, cy->cy_tpb.tpcmd, cy->cy_tpb.tpcontrol,
		    htoms(cy->cy_tpb.tpsize)));
		CY_GO(vm->um_addr);
		return;
	}
	/*
	 * Tape positioned incorrectly; set to seek forwards
	 * or backwards to the correct spot.  This happens 
	 * for raw tapes only on error retries.
	 */
	vm->um_tab.b_active = SSEEK;
	if (blkno < bp->b_blkno) {
		bp->b_command = CY_SFORW;
		cy->cy_tpb.tprec = htoms(bp->b_blkno - blkno);
	} else {
		bp->b_command = CY_SREV;
		cy->cy_tpb.tprec = htoms(blkno - bp->b_blkno);
	}
	yc->yc_timo = imin(imax((int)(10 * htoms(cy->cy_tpb.tprec)), 60), 5*60);
dobpcmd:
	/*
	 * Do the command in bp.  Reverse direction commands
	 * are indicated by having CYCW_REV or'd into their
	 * value.  For these we must set the appropriate bit
	 * in the control field.
	 */
	if (bp->b_command&CYCW_REV) {
		cy->cy_tpb.tpcmd = bp->b_command &~ CYCW_REV;
		cy->cy_tpb.tpcontrol = yc->yc_dens | CYCW_REV;
dlog((LOG_INFO, "cmd %x control %x\n", cy->cy_tpb.tpcmd, cy->cy_tpb.tpcontrol));
	} else {
		cy->cy_tpb.tpcmd = bp->b_command;
		cy->cy_tpb.tpcontrol = yc->yc_dens;
dlog((LOG_INFO, "cmd %x control %x\n", cy->cy_tpb.tpcmd, cy->cy_tpb.tpcontrol));
	}
	cy->cy_tpb.tpstatus = 0;
	cy->cy_tpb.tpcount = 0;
	cyldmba(cy->cy_tpb.tplink, (caddr_t)0);
	do
		uncache(&cy->cy_ccb.cbgate);
	while (cy->cy_ccb.cbgate == GATE_CLOSED);
	cyldmba(cy->cy_ccb.cbtpb, (caddr_t)&cy->cy_tpb);
	cy->cy_ccb.cbcw = CBCW_IE;
	cy->cy_ccb.cbgate = GATE_CLOSED;
	dlog((LOG_INFO, "CY_GO(%x) cmd %x control %x rec %d\n",
	    vm->um_addr, cy->cy_tpb.tpcmd, cy->cy_tpb.tpcontrol,
	    htoms(cy->cy_tpb.tprec)));
	CY_GO(vm->um_addr);
	return;
next:
	/*
	 * Done with this operation due to error or the
	 * fact that it doesn't do anything.
	 * Dequeue the transfer and continue
	 * processing this slave.
	 */
	vm->um_tab.b_errcnt = 0;
	dp->b_actf = bp->av_forw;
	biodone(bp);
	goto loop;
}

/*
 * Cy interrupt routine.
 */
cyintr(cyunit)
	int cyunit;
{
	struct buf *dp;
	register struct buf *bp;
	register struct vba_ctlr *vm = cyminfo[cyunit];
	register struct cy_softc *cy;
	register struct yc_softc *yc;
	int err;
	register state;

	dlog((LOG_INFO, "cyintr(%d)\n", cyunit));
	/*
	 * First, turn off the interrupt from the controller
	 * (device uses Multibus non-vectored interrupts...yech).
	 */
	cy = &cy_softc[vm->um_ctlr];
	cy->cy_ccb.cbcw = CBCW_CLRINT;
	cyldmba(cy->cy_ccb.cbtpb, (caddr_t)&cy->cy_nop);
	cy->cy_ccb.cbgate = GATE_CLOSED;
	CY_GO(vm->um_addr);
	if ((dp = vm->um_tab.b_actf) == NULL) {
		dlog((LOG_ERR, "cy%d: stray interrupt", vm->um_ctlr));
		return;
	}
	bp = dp->b_actf;
	cy = &cy_softc[cyunit];
	cyuncachetpb(cy);
	yc = &yc_softc[YCUNIT(bp->b_dev)];
	/*
	 * If last command was a rewind and tape is
	 * still moving, wait for the operation to complete.
	 */
	if (vm->um_tab.b_active == SREW) {
		vm->um_tab.b_active = SCOM;
		if ((cy->cy_tpb.tpstatus&CYS_RDY) == 0) {
			yc->yc_timo = 5*60;	/* 5 minutes */
			return;
		}
	}
	/*
	 * An operation completed...record status.
	 */
	yc->yc_timo = INF;
	yc->yc_control = cy->cy_tpb.tpcontrol;
	yc->yc_status = cy->cy_tpb.tpstatus;
	yc->yc_resid = bp->b_bcount - htoms(cy->cy_tpb.tpcount);
	dlog((LOG_INFO, "cmd %x control %b status %b resid %d\n",
	    cy->cy_tpb.tpcmd, yc->yc_control, CYCW_BITS,
	    yc->yc_status, CYS_BITS, yc->yc_resid));
	if ((bp->b_flags&B_READ) == 0)
		yc->yc_lastiow = 1;
	state = vm->um_tab.b_active;
	vm->um_tab.b_active = 0;
	/*
	 * Check for errors.
	 */
	if (cy->cy_tpb.tpstatus&CYS_ERR) {
		err = cy->cy_tpb.tpstatus&CYS_ERR;
		dlog((LOG_INFO, "error %d\n", err));
		/*
		 * If we hit the end of tape file, update our position.
		 */
		if (err == CYER_FM) {
			yc->yc_status |= CYS_FM;
			state = SCOM;		/* force completion */
			cyseteof(bp);		/* set blkno and nxrec */
			goto opdone;
		}
		/*
		 * Fix up errors which occur due to backspacing over
		 * the beginning of the tape.
		 */
		if (err == CYER_BOT && cy->cy_tpb.tpcontrol&CYCW_REV) {
			yc->yc_status |= CYS_BOT;
			goto ignoreerr;
		}
		/*
		 * If we were reading raw tape and the only error was that the
		 * record was too long, then we don't consider this an error.
		 */
		if ((bp->b_flags & (B_READ|B_RAW)) == (B_READ|B_RAW) &&
		    err == CYER_STROBE) {
			/*
			 * Retry reads with the command changed to
			 * a raw read if necessary.  Setting b_errcnt
			 * here causes cystart (above) to force a CY_RCOM.
			 */
			if (cy->cy_tpb.tpcmd == CY_BRCOM &&
			    vm->um_tab.b_errcnt++ == 0) {
				yc->yc_blkno++;
				goto opcont;
			} else
				goto ignoreerr;
		}
		/*
		 * If error is not hard, and this was an i/o operation
		 * retry up to 8 times.
		 */
		if (state == SIO && (CYMASK(err) &
		    ((bp->b_flags&B_READ) ? CYER_RSOFT : CYER_WSOFT))) {
			if (++vm->um_tab.b_errcnt < 7) {