sdata.c

著名操作系统Plan 9的第三版的部分核心源代码。现在很难找到了。Plan 9是bell实验室开发的Unix后继者。

			drive->c = drive->info[Ilcyl];
			drive->h = drive->info[Ilhead];
			drive->s = drive->info[Ilsec];
		}
		else{
			drive->c = drive->info[Iccyl];
			drive->h = drive->info[Ichead];
			drive->s = drive->info[Icsec];
		}
		if(drive->info[Icapabilities] & 0x0200){
			drive->sectors = (drive->info[Ilba1]<<16)
					 |drive->info[Ilba0];
			drive->dev |= Lba;
		}
		else
			drive->sectors = drive->c*drive->h*drive->s;
		atasetrwmode(drive, cmdport, ctlport, dev);
	}	

	drive->dma = 0;

	if(DEBUG & DbgCONFIG){
		print("dev %2.2uX capabilities %4.4uX config %4.4uX",
			dev, drive->info[Icapabilities], drive->info[Iconfig]);
		print(" mwdma %4.4uX dma %8.8uX", 
			drive->info[Imwdma], drive->dma);
		if(drive->info[Ivalid] & 0x04)
			print(" udma %4.4uX", drive->info[Iudma]);
		print("\n");
	}

	return drive;
}

static void
atasrst(int ctlport)
{
	/*
	 * Srst is a big stick and may cause problems if further
	 * commands are tried before the drives become ready again.
	 * Also, there will be problems here if overlapped commands
	 * are ever supported.
	 */
	microdelay(5);
	outb(ctlport+Dc, Srst);
	microdelay(5);
	outb(ctlport+Dc, 0);
	microdelay(2*1000);
}

static SDev*
ataprobe(int cmdport, int ctlport, int irq)
{
	Ctlr* ctlr;
	SDev *sdev;
	Drive *drive;
	int dev, error, rhi, rlo;

	/*
	 * Try to detect a floating bus.
	 * Bsy should be cleared. If not, see if the cylinder registers
	 * are read/write capable.
	 * If the master fails, try the slave to catch slave-only
	 * configurations.
	 * There's no need to restore the tested registers as they will
	 * be reset on any detected drives by the Cedd command.
	 * All this indicates is that there is at least one drive on the
	 * controller; when the non-existent drive is selected in a
	 * single-drive configuration the registers of the existing drive
	 * are often seen, only command execution fails.
	 */
	dev = Dev0;
	if(inb(ctlport+As) & Bsy){
		outb(cmdport+Dh, dev);
trydev1:
		atadebug(cmdport, ctlport, "ataprobe bsy");
		outb(cmdport+Cyllo, 0xAA);
		outb(cmdport+Cylhi, 0x55);
		outb(cmdport+Sector, 0xFF);
		rlo = inb(cmdport+Cyllo);
		rhi = inb(cmdport+Cylhi);
		if(rlo != 0xAA && (rlo == 0xFF || rhi != 0x55)){
			if(dev == Dev1){
release:
				return nil;
			}
			dev = Dev1;
			if(ataready(cmdport, ctlport, dev, Bsy, 0, 20*1000) < 0)
				goto trydev1;
		}
	}

	/*
	 * Disable interrupts on any detected controllers.
	 */
	outb(ctlport+Dc, Nien);
tryedd1:
	if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 100*1000) < 0){
		/*
		 * There's something there, but it didn't come up clean,
		 * so try hitting it with a big stick. The timing here is
		 * wrong but this is a last-ditch effort and it sometimes
		 * gets some marginal hardware back online.
		 */
		atasrst(ctlport);
		if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 100*1000) < 0)
			goto release;
	}

	/*
	 * Can only get here if controller is not busy.
	 * If there are drives Bsy will be set within 400nS,
	 * must wait 2mS before testing Status.
	 * Wait for the command to complete (6 seconds max).
	 */
	outb(cmdport+Command, Cedd);
	delay(2);
	if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 6*1000*1000) < 0)
		goto release;

	/*
	 * If bit 0 of the error register is set then the selected drive
	 * exists. This is enough to detect single-drive configurations.
	 * However, if the master exists there is no way short of executing
	 * a command to determine if a slave is present.
	 * It appears possible to get here testing Dev0 although it doesn't
	 * exist and the EDD won't take, so try again with Dev1.
	 */
	error = inb(cmdport+Error);
	atadebug(cmdport, ctlport, "ataprobe: dev %uX", dev);
	if((error & ~0x80) != 0x01){
		if(dev == Dev1)
			goto release;
		dev = Dev1;
		goto tryedd1;
	}

	/*
	 * At least one drive is known to exist, try to
	 * identify it. If that fails, don't bother checking
	 * any further.
	 * If the one drive found is Dev0 and the EDD command
	 * didn't indicate Dev1 doesn't exist, check for it.
	 */
	if((drive = ataidentify(cmdport, ctlport, dev)) == nil)
		goto release;
	if((ctlr = malloc(sizeof(Ctlr))) == nil){
		free(drive);
		goto release;
	}
	if((sdev = malloc(sizeof(SDev))) == nil){
		free(ctlr);
		free(drive);
		goto release;
	}
	drive->ctlr = ctlr;
	if(dev == Dev0){
		ctlr->drive[0] = drive;
		if(!(error & 0x80)){
			/*
			 * Always leave Dh pointing to a valid drive,
			 * otherwise a subsequent call to ataready on
			 * this controller may try to test a bogus Status.
			 * Ataprobe is the only place possibly invalid
			 * drives should be selected.
			 */
			drive = ataidentify(cmdport, ctlport, Dev1);
			if(drive != nil){
				drive->ctlr = ctlr;
				ctlr->drive[1] = drive;
			}
			else
				outb(cmdport+Dh, Dev0);
		}
	}
	else
		ctlr->drive[1] = drive;

	ctlr->cmdport = cmdport;
	ctlr->ctlport = ctlport;
	ctlr->irq = irq;

	sdev->ifc = &sdataifc;
	sdev->ctlr = ctlr;
	sdev->nunit = 2;

	return sdev;
}

static int
atasetsense(Drive* drive, int status, int key, int asc, int ascq)
{
	drive->sense[2] = key;
	drive->sense[12] = asc;
	drive->sense[13] = ascq;

	return status;
}

static int
atamodesense(Drive* drive, uchar* cmd)
{
	int len;

	/*
	 * Fake a vendor-specific request with page code 0,
	 * return the drive info.
	 */
	if((cmd[2] & 0x3F) != 0 && (cmd[2] & 0x3F) != 0x3F)
		return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
	len = (cmd[7]<<8)|cmd[8];
	if(len == 0)
		return SDok;
	if(len < 8+sizeof(drive->info))
		return atasetsense(drive, SDcheck, 0x05, 0x1A, 0);
	if(drive->data == nil || drive->dlen < len)
		return atasetsense(drive, SDcheck, 0x05, 0x20, 1);
	memset(drive->data, 0, 8);
	drive->data[0] = sizeof(drive->info)>>8;
	drive->data[1] = sizeof(drive->info);
	memmove(drive->data+8, drive->info, sizeof(drive->info));
	drive->data += 8+sizeof(drive->info);

	return SDok;
}

static void
atanop(Drive* drive, int subcommand)
{
	Ctlr* ctlr;
	int as, cmdport, ctlport, timeo;

	/*
	 * Attempt to abort a command by using NOP.
	 * In response, the drive is supposed to set Abrt
	 * in the Error register, set (Drdy|Err) in Status
	 * and clear Bsy when done. However, some drives
	 * (e.g. ATAPI Zip) just go Bsy then clear Status
	 * when done, hence the timeout loop only on Bsy
	 * and the forced setting of drive->error.
	 */
	ctlr = drive->ctlr;
	cmdport = ctlr->cmdport;
	outb(cmdport+Features, subcommand);
	outb(cmdport+Dh, drive->dev);
	outb(cmdport+Command, 0);

	microdelay(1);
	ctlport = ctlr->ctlport;
	for(timeo = 0; timeo < 1000; timeo++){
		as = inb(ctlport+As);
		if(!(as & Bsy))
			break;
		microdelay(1);
	}
	drive->error |= Abrt;
}

static int
atapktiodone(void* arg)
{
	return ((Ctlr*)arg)->done;
}

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:
ctlr->done=1;
		break;
	}
}

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

	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);

	if(ataready(cmdport, ctlport, drive->dev, Bsy|Drq, 0, 100*1000) < 0)
		return -1;

	ilock(ctlr);
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;
	outb(cmdport+Command, Cpkt);

	if((drive->info[Iconfig] & 0x0060) != 0x0020){
		as = ataready(cmdport, ctlport,
			drive->dev, Bsy, Drq|Chk, 4*1000);
		if(as < 0)
			r = SDtimeout;
		else if(as & Chk)
			r = SDcheck;
		else
			atapktinterrupt(drive);
	}
	ctlr->curdrive = drive;
	iunlock(ctlr);

	tsleep(ctlr, atapktiodone, ctlr, 10*1000);
	if(!ctlr->done)
		panic("atapktiodone");

	qunlock(ctlr);

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

	return r;
}

static int
atageniodone(void* arg)
{
	return ((Ctlr*)arg)->done;
}

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

	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, 100*1000) < 0)
		return -1;

	ilock(ctlr);
	if(drive->write)
		drive->command = drive->piow;
	else
		drive->command = drive->pior;

	outb(cmdport+Count, drive->count);
	outb(cmdport+Sector, s);
	outb(cmdport+Dh, drive->dev|h);
	outb(cmdport+Cyllo, c);
	outb(cmdport+Cylhi, c>>8);
	ctlr->done = 0;
	outb(cmdport+Command, drive->command);
	microdelay(1);

	switch(drive->command){
	case Cws:
	case Cwsm:
		as = ataready(cmdport, ctlport, drive->dev, Bsy, Drq|Err, 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:
panic("atadmastart");
		break;
	}
	ctlr->curdrive = drive;
	iunlock(ctlr);

	return 0;
}

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

	/*
	 * 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;