sdata.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

	return 0;
}

static void
atadmastart(Ctlr* ctlr, int write)
{
	if(write)
		outb(ctlr->bmiba+Bmicx, Ssbm);
	else
		outb(ctlr->bmiba+Bmicx, Rwcon|Ssbm);
}

static int
atadmastop(Ctlr* ctlr)
{
	int bmiba;

	bmiba = ctlr->bmiba;
	outb(bmiba+Bmicx, inb(bmiba+Bmicx) & ~Ssbm);

	return inb(bmiba+Bmisx);
}

static void
atadmainterrupt(Drive* drive, int count)
{
	Ctlr* ctlr;
	int bmiba, bmisx;

	ctlr = drive->ctlr;
	bmiba = ctlr->bmiba;
	bmisx = inb(bmiba+Bmisx);
	switch(bmisx & (Ideints|Idedmae|Bmidea)){
	case Bmidea:
		/*
		 * Data transfer still in progress, nothing to do
		 * (this should never happen).
		 */
		return;

	case Ideints:
	case Ideints|Bmidea:
		/*
		 * Normal termination, tidy up.
		 */
		drive->data += count;
		break;

	default:
		/*
		 * What's left are error conditions (memory transfer
		 * problem) and the device is not done but the PRD is
		 * exhausted. For both cases must somehow tell the
		 * drive to abort.
		 */
		ataabort(drive, 0);
		break;
	}
	atadmastop(ctlr);
	ctlr->done = 1;
}

static void
atapktinterrupt(Drive* drive)
{
	Ctlr* ctlr;
	int cmdport, len;

	ctlr = drive->ctlr;
	cmdport = ctlr->cmdport;
	switch(inb(cmdport+Ir) & (/*Rel|*/Io|Cd)){
	case Cd:
		outss(cmdport+Data, drive->pktcmd, drive->pkt/2);
		break;

	case 0:
		len = (inb(cmdport+Bytehi)<<8)|inb(cmdport+Bytelo);
		if(drive->data+len > drive->limit){
			atanop(drive, 0);
			break;
		}
		outss(cmdport+Data, drive->data, len/2);
		drive->data += len;
		break;

	case Io:
		len = (inb(cmdport+Bytehi)<<8)|inb(cmdport+Bytelo);
		if(drive->data+len > drive->limit){
			atanop(drive, 0);
			break;
		}
		inss(cmdport+Data, drive->data, len/2);
		drive->data += len;
		break;

	case Io|Cd:
		if(drive->pktdma)
			atadmainterrupt(drive, drive->dlen);
		else
			ctlr->done = 1;
		break;
	}
}

static int
atapktio(Drive* drive, uchar* cmd, int clen)
{
	Ctlr *ctlr;
	int as, cmdport, ctlport, len, r, timeo;

	if(cmd[0] == 0x5A && (cmd[2] & 0x3F) == 0)
		return atamodesense(drive, cmd);

	r = SDok;

	drive->command = Cpkt;
	memmove(drive->pktcmd, cmd, clen);
	memset(drive->pktcmd+clen, 0, drive->pkt-clen);
	drive->limit = drive->data+drive->dlen;

	ctlr = drive->ctlr;
	cmdport = ctlr->cmdport;
	ctlport = ctlr->ctlport;

	qlock(ctlr);

	as = ataready(cmdport, ctlport, drive->dev, Bsy|Drq, 0, 107*1000);
	/* used to test as&Chk as failure too, but some CD readers use that for media change */
	if(as < 0){
		qunlock(ctlr);
		return -1;
	}

	ilock(ctlr);
	if(drive->dlen && drive->dmactl && !atadmasetup(drive, drive->dlen))
		drive->pktdma = Dma;
	else
		drive->pktdma = 0;

	outb(cmdport+Features, drive->pktdma);
	outb(cmdport+Count, 0);
	outb(cmdport+Sector, 0);
	len = 16*drive->secsize;
	outb(cmdport+Bytelo, len);
	outb(cmdport+Bytehi, len>>8);
	outb(cmdport+Dh, drive->dev);
	ctlr->done = 0;
	ctlr->curdrive = drive;
	ctlr->command = Cpkt;		/* debugging */
	if(drive->pktdma)
		atadmastart(ctlr, drive->write);
	outb(cmdport+Command, Cpkt);

	if((drive->info[Iconfig] & Mdrq) != 0x0020){
		microdelay(1);
		as = ataready(cmdport, ctlport, 0, Bsy, Drq|Chk, 4*1000);
		if(as < 0 || (as & (Bsy|Chk))){
			drive->status = as<0 ? 0 : as;
			ctlr->curdrive = nil;
			ctlr->done = 1;
			r = SDtimeout;
		}else
			atapktinterrupt(drive);
	}
	iunlock(ctlr);

	while(waserror())
		;
	if(!drive->pktdma)
		sleep(ctlr, atadone, ctlr);
	else for(timeo = 0; !ctlr->done; timeo++){
		tsleep(ctlr, atadone, ctlr, 1000);
		if(ctlr->done)
			break;
		ilock(ctlr);
		atadmainterrupt(drive, 0);
		if(!drive->error && timeo > 20){
			ataabort(drive, 0);
			atadmastop(ctlr);
			drive->dmactl = 0;
			drive->error |= Abrt;
		}
		if(drive->error){
			drive->status |= Chk;
			ctlr->curdrive = nil;
		}
		iunlock(ctlr);
	}
	poperror();

	qunlock(ctlr);

	if(drive->status & Chk)
		r = SDcheck;

	return r;
}

static uchar cmd48[256] = {
	[Crs]	Crs48,
	[Crd]	Crd48,
	[Crdq]	Crdq48,
	[Crsm]	Crsm48,
	[Cws]	Cws48,
	[Cwd]	Cwd48,
	[Cwdq]	Cwdq48,
	[Cwsm]	Cwsm48,
};

static int
atageniostart(Drive* drive, vlong lba)
{
	Ctlr *ctlr;
	uchar cmd;
	int as, c, cmdport, ctlport, h, len, s, use48;

	use48 = 0;
	if((drive->flags&Lba48always) || (lba>>28) || drive->count > 256){
		if(!(drive->flags & Lba48))
			return -1;
		use48 = 1;
		c = h = s = 0;
	}
	else if(drive->dev & Lba){
		c = (lba>>8) & 0xFFFF;
		h = (lba>>24) & 0x0F;
		s = lba & 0xFF;
	}
	else{
		c = lba/(drive->s*drive->h);
		h = ((lba/drive->s) % drive->h);
		s = (lba % drive->s) + 1;
	}

	ctlr = drive->ctlr;
	cmdport = ctlr->cmdport;
	ctlport = ctlr->ctlport;
	if(ataready(cmdport, ctlport, drive->dev, Bsy|Drq, 0, 101*1000) < 0)
		return -1;

	ilock(ctlr);
	if(drive->dmactl && !atadmasetup(drive, drive->count*drive->secsize)){
		if(drive->write)
			drive->command = Cwd;
		else
			drive->command = Crd;
	}
	else if(drive->rwmctl){
		drive->block = drive->rwm*drive->secsize;
		if(drive->write)
			drive->command = Cwsm;
		else
			drive->command = Crsm;
	}
	else{
		drive->block = drive->secsize;
		if(drive->write)
			drive->command = Cws;
		else
			drive->command = Crs;
	}
	drive->limit = drive->data + drive->count*drive->secsize;
	cmd = drive->command;
	if(use48){
		outb(cmdport+Count, (drive->count>>8) & 0xFF);
		outb(cmdport+Count, drive->count & 0XFF);
		outb(cmdport+Lbalo, (lba>>24) & 0xFF);
		outb(cmdport+Lbalo, lba & 0xFF);
		outb(cmdport+Lbamid, (lba>>32) & 0xFF);
		outb(cmdport+Lbamid, (lba>>8) & 0xFF);
		outb(cmdport+Lbahi, (lba>>40) & 0xFF);
		outb(cmdport+Lbahi, (lba>>16) & 0xFF);
		outb(cmdport+Dh, drive->dev|Lba);
		cmd = cmd48[cmd];

		if(DEBUG & Dbg48BIT)
			print("using 48-bit commands\n");
	}
	else{
		outb(cmdport+Count, drive->count);
		outb(cmdport+Sector, s);
		outb(cmdport+Cyllo, c);
		outb(cmdport+Cylhi, c>>8);
		outb(cmdport+Dh, drive->dev|h);
	}
	ctlr->done = 0;
	ctlr->curdrive = drive;
	ctlr->command = drive->command;	/* debugging */
	outb(cmdport+Command, cmd);

	switch(drive->command){
	case Cws:
	case Cwsm:
		microdelay(1);
		/* 10*1000 for flash ide drives - maybe detect them? */
		as = ataready(cmdport, ctlport, 0, Bsy, Drq|Err, 10*1000);
		if(as < 0 || (as & Err)){
			iunlock(ctlr);
			return -1;
		}
		len = drive->block;
		if(drive->data+len > drive->limit)
			len = drive->limit-drive->data;
		outss(cmdport+Data, drive->data, len/2);
		break;

	case Crd:
	case Cwd:
		atadmastart(ctlr, drive->write);
		break;
	}
	iunlock(ctlr);

	return 0;
}

static int
atagenioretry(Drive* drive)
{
	if(drive->dmactl){
		drive->dmactl = 0;
		print("atagenioretry: disabling dma\n");
	}
	else if(drive->rwmctl)
		drive->rwmctl = 0;
	else
		return atasetsense(drive, SDcheck, 4, 8, drive->error);

	return SDretry;
}

static int
atagenio(Drive* drive, uchar* cmd, int)
{
	uchar *p;
	Ctlr *ctlr;
	vlong lba, len;
	int count, maxio;

	/*
	 * Map SCSI commands into ATA commands for discs.
	 * Fail any command with a LUN except INQUIRY which
	 * will return 'logical unit not supported'.
	 */
	if((cmd[1]>>5) && cmd[0] != 0x12)
		return atasetsense(drive, SDcheck, 0x05, 0x25, 0);

	switch(cmd[0]){
	default:
		return atasetsense(drive, SDcheck, 0x05, 0x20, 0);

	case 0x00:			/* test unit ready */
		return SDok;

	case 0x03:			/* request sense */
		if(cmd[4] < sizeof(drive->sense))
			len = cmd[4];
		else
			len = sizeof(drive->sense);
		if(drive->data && drive->dlen >= len){
			memmove(drive->data, drive->sense, len);
			drive->data += len;
		}
		return SDok;

	case 0x12:			/* inquiry */
		if(cmd[4] < sizeof(drive->inquiry))
			len = cmd[4];
		else
			len = sizeof(drive->inquiry);
		if(drive->data && drive->dlen >= len){
			memmove(drive->data, drive->inquiry, len);
			drive->data += len;
		}
		return SDok;

	case 0x1B:			/* start/stop unit */
		/*
		 * NOP for now, can use the power management feature
		 * set later.
		 */
		return SDok;

	case 0x25:			/* read capacity */
		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
			return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
		if(drive->data == nil || drive->dlen < 8)
			return atasetsense(drive, SDcheck, 0x05, 0x20, 1);
		/*
		 * Read capacity returns the LBA of the last sector.
		 */
		len = drive->sectors-1;
		p = drive->data;
		*p++ = len>>24;
		*p++ = len>>16;
		*p++ = len>>8;
		*p++ = len;
		len = drive->secsize;
		*p++ = len>>24;
		*p++ = len>>16;
		*p++ = len>>8;
		*p = len;
		drive->data += 8;
		return SDok;

	case 0x9E:			/* long read capacity */
		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
			return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
		if(drive->data == nil || drive->dlen < 8)
			return atasetsense(drive, SDcheck, 0x05, 0x20, 1);
		/*
		 * Read capacity returns the LBA of the last sector.
		 */
		len = drive->sectors-1;
		p = drive->data;
		*p++ = len>>56;
		*p++ = len>>48;
		*p++ = len>>40;
		*p++ = len>>32;
		*p++ = len>>24;
		*p++ = len>>16;
		*p++ = len>>8;
		*p++ = len;
		len = drive->secsize;
		*p++ = len>>24;
		*p++ = len>>16;
		*p++ = len>>8;
		*p = len;
		drive->data += 12;
		return SDok;

	case 0x28:			/* read */
	case 0x2A:			/* write */
		break;

	case 0x5A:
		return atamodesense(drive, cmd);
	}

	ctlr = drive->ctlr;
	lba = (cmd[2]<<24)|(cmd[3]<<16)|(cmd[4]<<8)|cmd[5];
	count = (cmd[7]<<8)|cmd[8];
	if(drive->data == nil)
		return SDok;
	if(drive->dlen < count*drive->secsize)
		count = drive->dlen/drive->secsize;
	qlock(ctlr);
	if(ctlr->maxio)
		maxio = ctlr->maxio;
	else if(drive->flags & Lba48)
		maxio = 65536;
	else
		maxio = 256;
	while(count){
		if(count > maxio)
			drive->count = maxio;
		else
			drive->count = count;
		if(atageniostart(drive, lba)){
			ilock(ctlr);
			atanop(drive, 0);
			iunlock(ctlr);
			qunlock(ctlr);
			return atagenioretry(drive);
		}

		while(waserror())
			;
		tsleep(ctlr, atadone, ctlr, 60*1000);
		poperror();
		if(!ctlr->done){
			/*
			 * What should the above timeout be? In
			 * standby and sleep modes it could take as
			 * long as 30 seconds for a drive to respond.
			 * Very hard to get out of this cleanly.
			 */
			atadumpstate(drive, cmd, lba, count);
			ataabort(drive, 1);
			qunlock(ctlr);
			return atagenioretry(drive);
		}

		if(drive->status & Err){
			qunlock(ctlr);
			return atasetsense(drive, SDcheck, 4, 8, drive->error);
		}
		count -= drive->count;
		lba += drive->count;
	}
	qunlock(ctlr);

	return SDok;
}

static int
atario(SDreq* r)
{
	Ctlr *ctlr;
	Drive *drive;
	SDunit *unit;
	uchar cmd10[10], *cmdp, *p;
	int clen, reqstatus, status;

	unit = r->unit;
	if((ctlr = unit->dev->ctlr) == nil || ctlr->drive[unit->subno] == nil){
		r->status = SDtimeout;
		return SDtimeout;
	}
	drive = ctlr->drive[unit->subno];

	/*
	 * Most SCSI commands can be passed unchanged except for
	 * the padding on the end. The few which require munging
	 * are not used internally. Mode select/sense(6) could be
	 * converted to the 10-byte form but it's not worth the
	 * effort. Read/write(6) are easy.
	 */
	switch(r->cmd[0]){
	case 0x08:			/* read */
	case 0x0A:			/* write */
		cmdp = cmd10;
		memset(cmdp, 0, sizeof(cmd10));
		cmdp[0] = r->cmd[0]|0x20;
		cmdp[1] = r->cmd[1] & 0xE0;
		cmdp[5] = r->cmd[3];
		cmdp[4] = r->cmd[2];
		cmdp[3] = r->cmd[1] & 0x0F;
		cmdp[8] = r->cmd[4];
		clen = sizeof(cmd10);
		break;

	default:
		cmdp = r->cmd;
		clen = r->clen;
		break;
	}

	qlock(drive);
retry:
	drive->write = r->write;
	drive->data = r->data;
	drive->dlen = r->dlen;

	drive->status = 0;
	drive->error = 0;
	if(drive->pkt)
		status = atapktio(drive, cmdp, clen);
	else
		status = atagenio(drive, cmdp, clen);
	if(status == SDretry){
		if(DbgDEBUG)
			print("%s: retry: dma %8.8uX rwm %4.4uX\n",
				unit->name, drive->dmactl, drive->rwmctl);
		goto retry;
	}
	if(status == SDok){
		atasetsense(drive, SDok, 0, 0, 0);
		if(drive->data){
			p = r->data;
			r->rlen = drive->data - p;
		}
		else
			r->rlen = 0;
	}
	else if(status == SDcheck && !(r->flags & SDnosense)){
		drive->write = 0;
		memset(cmd10, 0, sizeof(cmd10));