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

		}
		else if(dev){
			outb(cmdport+Dh, dev);
			dev = 0;
		}
		else if(ready == 0 || (as & ready)){
			atadebug(0, 0, "ataready: %d 0x%2.2uX\n", micro, as);
			return as;
		}

		if(micro-- <= 0){
			atadebug(0, 0, "ataready: %d 0x%2.2uX\n", micro, as);
			break;
		}
		microdelay(1);
	}
	atadebug(cmdport, ctlport, "ataready: timeout");

	return -1;
}

/*
static int
atacsf(Drive* drive, vlong csf, int supported)
{
	ushort *info;
	int cmdset, i, x;

	if(supported)
		info = &drive->info[Icsfs];
	else
		info = &drive->info[Icsfe];

	for(i = 0; i < 3; i++){
		x = (csf>>(16*i)) & 0xFFFF;
		if(x == 0)
			continue;
		cmdset = info[i];
		if(cmdset == 0 || cmdset == 0xFFFF)
			return 0;
		return cmdset & x;
	}

	return 0;
}
*/

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

static int
atarwmmode(Drive* drive, int cmdport, int ctlport, int dev)
{
	int as, maxrwm, rwm;

	maxrwm = (drive->info[Imaxrwm] & 0xFF);
	if(maxrwm == 0)
		return 0;

	/*
	 * Sometimes drives come up with the current count set
	 * to 0; if so, set a suitable value, otherwise believe
	 * the value in Irwm if the 0x100 bit is set.
	 */
	if(drive->info[Irwm] & 0x100)
		rwm = (drive->info[Irwm] & 0xFF);
	else
		rwm = 0;
	if(rwm == 0)
		rwm = maxrwm;
	if(rwm > 16)
		rwm = 16;
	if(ataready(cmdport, ctlport, dev, Bsy|Drq, Drdy, 102*1000) < 0)
		return 0;
	outb(cmdport+Count, rwm);
	outb(cmdport+Cmd, Csm);
	microdelay(1);
	as = ataready(cmdport, ctlport, 0, Bsy, Drdy|Df|Err, 1000);
	inb(cmdport+Status);
	if(as < 0 || (as & (Df|Err)))
		return 0;

	drive->rwm = rwm;
	if (conf.idedma)
		drive->rwmctl = drive->rwm;	/* FS special */
	else
		drive->rwm = 0;
	return rwm;
}

static int
atadmamode(Drive* drive)
{
	int dma;

	/*
	 * Check if any DMA mode enabled.
	 * Assumes the BIOS has picked and enabled the best.
	 * This is completely passive at the moment, no attempt is
	 * made to ensure the hardware is correctly set up.
	 */
	dma = drive->info[Imwdma] & 0x0707;
	drive->dma = (dma>>8) & dma;
	if(drive->dma == 0 && (drive->info[Ivalid] & 0x04)){
		dma = drive->info[Iudma] & 0x7F7F;
		drive->dma = (dma>>8) & dma;
		if(drive->dma)
			drive->dma |= 'U'<<16;
	}
	if (conf.idedma)
		drive->dmactl = drive->dma;	/* FS special */
	else
		drive->dma = 0;
	return dma;
}

static int
ataidentify(int cmdport, int ctlport, int dev, int pkt, void* info)
{
	int as, command, drdy;

	if(pkt){
		command = Cidpkt;
		drdy = 0;
	}
	else{
		command = Cid;
		drdy = Drdy;
	}
	as = ataready(cmdport, ctlport, dev, Bsy|Drq, drdy, 103*1000);
	if(as < 0)
		return as;
	outb(cmdport+Cmd, command);
	microdelay(1);

	as = ataready(cmdport, ctlport, 0, Bsy, Drq|Err, 400*1000);
	if(as < 0)
		return -1;
	if(as & Err)
		return as;

	memset(info, 0, 512);
	inss(cmdport+Data, info, 256);
	inb(cmdport+Status);

	if(DEBUG & DbgIDENTIFY){
		int i;
		ushort *sp;

		sp = (ushort*)info;
		for(i = 0; i < 256; i++){
			if(i && (i%16) == 0)
				print("\n");
			print(" %4.4uX", *sp);
			sp++;
		}
		print("\n");
	}

	return 0;
}

/*
 * DEBUGGING only.
 * write, read and verify block 1 (never used in an fs otherwise)
 * to see if dma and rwm actually work.
 * if not, turn them off, though the kernel could be corrupt by then.
 */
static void
ataverify(Drive *dp)
{
	int n, nb, dev = dp->driveno;
	uchar *buf = dp->buf;

	if (dp->ctlr == nil)
		panic("ataverify: nil ctlr for drive");
	atadriveprobe(dev);
	print("ataverify h%d...", dev);
	for (n = 0; n < RBUFSIZE; n++)
		buf[n] = n;
	if (ataseek(dev, RBUFSIZE) < 0)
		panic("ataverify: seek 1");
	nb = atawrite(dev, buf, RBUFSIZE);
	if (nb != RBUFSIZE)
		print("short write of %d bytes to block 1\n", nb);
	else {
		for (n = 0; n < RBUFSIZE; n++)
			buf[n] = ~n;
		if (ataseek(dev, RBUFSIZE) < 0)
			panic("ataverify: seek 1");
		nb = ataread(dev, buf, RBUFSIZE);
		if (nb != RBUFSIZE)
			print("short read of %d bytes to block 1\n", nb);
		else {
			for (n = 0; n < RBUFSIZE; n++)
				if ((uchar)buf[n] != (uchar)n)
					break;
			if (n == RBUFSIZE) {
				print("OK\n");
				return;			/* verified OK */
			}
			print("byte comparison failed\n");
		}
	}
	print("ataverify: disabling dma and rwm\n");
	dp->dmactl = dp->rwmctl = 0;
}

static Drive*
atagetdrive(int cmdport, int ctlport, int dev)
{
	Drive *drive;
	int as, i, pkt, driveno;
	uchar buf[512], *p;
	ushort iconfig, *sp;

	driveno = (cmdport == Ctlr0cmd? 0:
		cmdport == Ctlr1cmd? NCtlrdrv: 2*NCtlrdrv);
	if (dev == Dev1)
		driveno++;

	atadebug(0, 0, "identify: port 0x%uX dev 0x%2.2uX\n", cmdport, dev);
	pkt = 1;
retry:
	as = ataidentify(cmdport, ctlport, dev, pkt, buf);
	if(as < 0)
		return nil;
	if(as & Err){
		if(pkt == 0)
			return nil;
		pkt = 0;
		goto retry;
	}

	if((drive = malloc(sizeof(Drive))) == nil)
		return nil;
	drive->dev = dev;
	drive->driveno = -1;				/* unset */
	memmove(drive->info, buf, sizeof(drive->info));
	drive->sense[0] = 0x70;
	drive->sense[7] = sizeof(drive->sense)-7;

	drive->inquiry[2] = 2;
	drive->inquiry[3] = 2;
	drive->inquiry[4] = sizeof(drive->inquiry)-4;
	p = &drive->inquiry[8];
	sp = &drive->info[Imodel];
	for(i = 0; i < 20; i++){
		*p++ = *sp>>8;
		*p++ = *sp++;
	}

	drive->secsize = 512;

	/*
	 * Beware the CompactFlash Association feature set.
	 * Now, why this value in Iconfig just walks all over the bit
	 * definitions used in the other parts of the ATA/ATAPI standards
	 * is a mystery and a sign of true stupidity on someone's part.
	 * Anyway, the standard says if this value is 0x848A then it's
	 * CompactFlash and it's NOT a packet device.
	 */
	iconfig = drive->info[Iconfig];
	if(iconfig != 0x848A && (iconfig & 0xC000) == 0x8000){
		print("atagetdrive: port 0x%uX dev 0x%2.2uX: packet device\n",
			cmdport, dev);
		if(iconfig & 0x01)
			drive->pkt = 16;
		else
			drive->pkt = 12;
	}
	else{
		if (iconfig == 0x848A)
			print("atagetdrive: port 0x%uX dev 0x%2.2uX: non-packet CF device\n",
				cmdport, dev);
		if(drive->info[Ivalid] & 0x0001){
			drive->c = drive->info[Iccyl];
			drive->h = drive->info[Ichead];
			drive->s = drive->info[Icsec];
		}else{
			drive->c = drive->info[Ilcyl];
			drive->h = drive->info[Ilhead];
			drive->s = drive->info[Ilsec];
		}
		if(drive->info[Icapabilities] & Mlba){
			if(drive->info[Icsfs+1] & Maddr48){
				drive->sectors = drive->info[Ilba48]
					| (drive->info[Ilba48+1]<<16)
					| ((Devsize)drive->info[Ilba48+2]<<32);
				drive->flags |= Lba48;
			}else
				drive->sectors = (drive->info[Ilba+1]<<16)
					 |drive->info[Ilba];
			drive->dev |= Lba;
			drive->lba = 1;
		}else
			drive->sectors = drive->c * drive->h * drive->s;
		atarwmmode(drive, cmdport, ctlport, dev);
	}
	atadmamode(drive);

	if(DEBUG & DbgCONFIG){
		print("ata h%d: dev %2.2uX port %uX config %4.4uX capabilities %4.4uX",
			driveno, dev, cmdport, iconfig,
			drive->info[Icapabilities]);
		print(" mwdma %4.4uX", drive->info[Imwdma]);
		if(drive->info[Ivalid] & 0x04)
			print(" udma %4.4uX", drive->info[Iudma]);
		print(" dma %8.8uX rwm %ud\n", drive->dma, drive->rwm);
		if(drive->flags&Lba48)
			print("\tLLBA sectors %lld\n", (Wideoff)drive->sectors);
	}
	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 int drivenum = 0;	/* hope that we probe in order */

static void
updprobe(int cmdport)
{
	if(cmdport == Ctlr0cmd)
		drivenum = NCtlrdrv;
	else if (cmdport == Ctlr1cmd)
		drivenum = 2*NCtlrdrv;
}

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

	if(cmdport == Ctlr0cmd)
		drivenum = 0;
	else if (cmdport == Ctlr1cmd)
		drivenum = NCtlrdrv;

	if(ioalloc(cmdport, 8, 0, "atacmd") < 0) {
		print("ataprobe: Cannot allocate %X\n", cmdport);
		updprobe(cmdport);
		return nil;
	}
	if(ioalloc(ctlport+As, 1, 0, "atactl") < 0){
		print("ataprobe: Cannot allocate %X\n", ctlport + As);
		iofree(cmdport);
		updprobe(cmdport);
		return nil;
	}

	/*
	 * 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);
		microdelay(1);
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:
				iofree(cmdport);
				iofree(ctlport+As);
				updprobe(cmdport);
				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, 105*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, 106*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+Cmd, 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 = atagetdrive(cmdport, ctlport, dev)) == nil)
		goto release;
	if((ctlr = malloc(sizeof(Ctlr))) == nil){
		free(drive);
		goto release;
	}
	memset(ctlr, 0, sizeof(Ctlr));
	if((sdev = malloc(sizeof(SDev))) == nil){
		free(ctlr);
		free(drive);
		goto release;
	}
	memset(sdev, 0, sizeof(SDev));
	drive->ctlr = ctlr;

	atactlr[drivenum/NCtlrdrv] = ctlr;
	atadrive[drivenum++] = drive;
	sdevs[drivenum/NCtlrdrv] = sdev;

	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 = atagetdrive(cmdport, ctlport, Dev1);
			if(drive != nil){
				drive->ctlr = ctlr;
				ctlr->drive[1] = drive;
			}
			else{
				outb(cmdport+Dh, Dev0);
				microdelay(1);
			}
			atadrive[drivenum] = drive;
		}
	}
	else
		ctlr->drive[1] = drive;
	drivenum++;

	print("ata%d: cmd 0x%ux ctl 0x%ux irq %d\n",
		(drivenum-1)/NCtlrdrv, cmdport, ctlport, irq);
	ctlr->cmdport = cmdport;
	ctlr->ctlport = ctlport;
	ctlr->irq = irq;
	ctlr->tbdf = BUSUNKNOWN;
	ctlr->command = Cedd;		/* debugging */

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

	if (0)
		for (i = drivenum - 2; i < drivenum; i++)
			if (atadrive[i])
				ataverify(atadrive[i]);
	updprobe(cmdport);
	return sdev;
}

static void
ataclear(SDev *sdev)
{
	Ctlr* ctlr;

	ctlr = sdev->ctlr;
	iofree(ctlr->cmdport);
	iofree(ctlr->ctlport + As);

	if (ctlr->drive[0])
		free(ctlr->drive[0]);
	if (ctlr->drive[1])
		free(ctlr->drive[1]);
	/* TODO: clear entries in atadrive[] too */
	if (sdev->name)
		free(sdev->name);
	free(ctlr);
	free(sdev);
}

static char *
atastat(SDev *sdev, char *p, char *e)
{
	Ctlr *ctlr = sdev->ctlr;

	return seprint(p, e, "%s ata port %X ctl %X irq %d\n",
			sdev->name, ctlr->cmdport, ctlr->ctlport, ctlr->irq);
}

#ifndef FS
static SDev*
ataprobew(DevConf *cf)
{
	if (cf->nports != 2)
		error(Ebadarg);

	return ataprobe(cf->ports[0].port, cf->ports[1].port, cf->intnum);
}
#endif

static int
atasetsense(Drive* drive, int status, int key, int asc, int ascq)