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

	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));
		cmd10[0] = 0x03;
		cmd10[1] = r->lun<<5;
		cmd10[4] = sizeof(r->sense)-1;
		drive->data = r->sense;
		drive->dlen = sizeof(r->sense)-1;
		drive->status = 0;
		drive->error = 0;
		if(drive->pkt)
			reqstatus = atapktio(drive, cmd10, 6);
		else
			reqstatus = atagenio(drive, cmd10, 6);
		if(reqstatus == SDok){
			r->flags |= SDvalidsense;
			atasetsense(drive, SDok, 0, 0, 0);
		}
	}
	qunlock(drive);
	r->status = status;
	if(status != SDok)
		return status;

	/*
	 * Fix up any results.
	 * Many ATAPI CD-ROMs ignore the LUN field completely and
	 * return valid INQUIRY data. Patch the response to indicate
	 * 'logical unit not supported' if the LUN is non-zero.
	 */
	switch(cmdp[0]){
	case 0x12:			/* inquiry */
		if((p = r->data) == nil)
			break;
		if((cmdp[1]>>5) && (!drive->pkt || (p[0] & 0x1F) == 0x05))
			p[0] = 0x7F;
		/*FALLTHROUGH*/
	default:
		break;
	}

	return SDok;
}


static void
atainterrupt(Ureg*, void*arg )
{
	Ctlr *ctlr;
	Drive *drive;
	int cmdport, len, status;

	ctlr = arg;

	ilock(ctlr);
	if(inb(ctlr->ctlport+As) & Bsy){
		iunlock(ctlr);
		if(DEBUG & DbgDEBUG)
			print("IBsy+");
		return;
	}
	cmdport = ctlr->cmdport;
	status = inb(cmdport+Status);
	if((drive = ctlr->curdrive) == nil){
		iunlock(ctlr);
		if((DEBUG & DbgDEBUG) && ctlr->command != Cedd)
			print("Inil%2.2uX/%2.2uX+", ctlr->command, status);
		return;
	}

	if(status & Err)
		drive->error = inb(cmdport+Error);
	else switch(drive->command){
	default:
		drive->error = Abrt;
		break;

	case Crs:
	case Crsm:
		if(!(status & Drq)){
			drive->error = Abrt;
			break;
		}
		len = drive->block;
		if(drive->data+len > drive->limit)
			len = drive->limit-drive->data;
		inss(cmdport+Data, drive->data, len/2);
		drive->data += len;
		if(drive->data >= drive->limit)
			ctlr->done = 1;
		break;

	case Cws:
	case Cwsm:
		len = drive->block;
		if(drive->data+len > drive->limit)
			len = drive->limit-drive->data;
		drive->data += len;
		if(drive->data >= drive->limit){
			ctlr->done = 1;
			break;
		}
		if(!(status & Drq)){
			drive->error = Abrt;
			break;
		}
		len = drive->block;
		if(drive->data+len > drive->limit)
			len = drive->limit-drive->data;
		outss(cmdport+Data, drive->data, len/2);
		break;

	case Cpkt:
		atapktinterrupt(drive);
		break;

	case Crd:
	case Cwd:
		atadmainterrupt(drive, drive->count*drive->secsize);
		break;

	case Cstandby:
		ctlr->done = 1;
		break;
	}
	iunlock(ctlr);

	if(drive->error){
		status |= Err;
		ctlr->done = 1;
	}

	if(ctlr->done){
		ctlr->curdrive = nil;
		drive->status = status;
		wakeup(ctlr);
	}
}

#ifdef notdef
static SDev*
atapnp(void)
{
	int	cmdport;
	int	ctlport;
	int	irq;

	cmdport = 0x200;
	ctlport = cmdport + 0x0C;
	irq = 10;
	return ataprobe(cmdport, ctlport, irq);
}
#endif


static SDev*
atalegacy(int port, int irq)
{
	return ataprobe(port, port+0x204, irq);
}

static int ataitype;
static int atairq;
static int
ataenable(SDev* sdev)
{
	Ctlr *ctlr;
	char name[KNAMELEN];

	ctlr = sdev->ctlr;

	if(ctlr->bmiba){
		ctlr->prdt = xspanalloc(Nprd*sizeof(Prd), 4, 4*1024);
	}
	snprint(name, KNAMELEN, "%s (%s)", sdev->name, sdev->ifc->name);
//	intrenable(ctlr->irq, atainterrupt, ctlr, ctlr->tbdf, name);
	outb(ctlr->ctlport+Dc, 0);
	intrenable(ataitype, atairq, atainterrupt, ctlr, name);
	if(ctlr->ienable)
		ctlr->ienable(ctlr);

	return 1;
}

static int
atarctl(SDunit* unit, char* p, int l)
{
	int n;
	Ctlr *ctlr;
	Drive *drive;

	if((ctlr = unit->dev->ctlr) == nil || ctlr->drive[unit->subno] == nil)
		return 0;
	drive = ctlr->drive[unit->subno];

	qlock(drive);
	n = snprint(p, l, "config %4.4uX capabilities %4.4uX",
		drive->info[Iconfig], drive->info[Icapabilities]);
	if(drive->dma)
		n += snprint(p+n, l-n, " dma %8.8uX dmactl %8.8uX",
			drive->dma, drive->dmactl);
	if(drive->rwm)
		n += snprint(p+n, l-n, " rwm %ud rwmctl %ud",
			drive->rwm, drive->rwmctl);
	n += snprint(p+n, l-n, "\n");
	if(unit->sectors){
		n += snprint(p+n, l-n, "geometry %ld %ld",
			unit->sectors, unit->secsize);
		if(drive->pkt == 0)
			n += snprint(p+n, l-n, " %d %d %d",
				drive->c, drive->h, drive->s);
		n += snprint(p+n, l-n, "\n");
	}
	qunlock(drive);

	return n;
}

static int
atawctl(SDunit* unit, Cmdbuf* cb)
{
	int period;
	Ctlr *ctlr;
	Drive *drive;

	if((ctlr = unit->dev->ctlr) == nil || ctlr->drive[unit->subno] == nil)
		return 0;
	drive = ctlr->drive[unit->subno];

	qlock(drive);
	if(waserror()){
		qunlock(drive);
		nexterror();
	}

	/*
	 * Dma and rwm control is passive at the moment,
	 * i.e. it is assumed that the hardware is set up
	 * correctly already either by the BIOS or when
	 * the drive was initially identified.
	 */
	if(strcmp(cb->f[0], "dma") == 0){
		if(cb->nf != 2 || drive->dma == 0)
			error(Ebadctl);
		if(strcmp(cb->f[1], "on") == 0)
			drive->dmactl = drive->dma;
		else if(strcmp(cb->f[1], "off") == 0)
			drive->dmactl = 0;
		else
			error(Ebadctl);
	}
	else if(strcmp(cb->f[0], "rwm") == 0){
		if(cb->nf != 2 || drive->rwm == 0)
			error(Ebadctl);
		if(strcmp(cb->f[1], "on") == 0)
			drive->rwmctl = drive->rwm;
		else if(strcmp(cb->f[1], "off") == 0)
			drive->rwmctl = 0;
		else
			error(Ebadctl);
	}
	else if(strcmp(cb->f[0], "standby") == 0){
		switch(cb->nf){
		default:
			error(Ebadctl);
		case 2:
			period = strtol(cb->f[1], 0, 0);
			if(period && (period < 30 || period > 240*5))
				error(Ebadctl);
			period /= 5;
			break;
		}
		if(atastandby(drive, period) != SDok)
			error(Ebadctl);
	}
	else
		error(Ebadctl);
	qunlock(drive);
	poperror();

	return 0;
}

static int
scsitest(SDreq* r)
{
	r->write = 0;
	memset(r->cmd, 0, sizeof(r->cmd));
	r->cmd[1] = r->lun<<5;
	r->clen = 6;
	r->data = nil;
	r->dlen = 0;
	r->flags = 0;

	r->status = ~0;

	return r->unit->dev->ifc->rio(r);
}

static int
scsirio(SDreq* r)
{
	/*
	 * Perform an I/O request, returning
	 *	-1	failure
	 *	 0	ok
	 *	 1	no medium present
	 *	 2	retry
	 * The contents of r may be altered so the
	 * caller should re-initialise if necesary.
	 */
	r->status = ~0;
	switch(r->unit->dev->ifc->rio(r)){
	default:
		return -1;
	case SDcheck:
		if(!(r->flags & SDvalidsense))
			return -1;
		switch(r->sense[2] & 0x0F){
		case 0x00:		/* no sense */
		case 0x01:		/* recovered error */
			return 2;
		case 0x06:		/* check condition */
			/*
			 * 0x28 - not ready to ready transition,
			 *	  medium may have changed.
			 * 0x29 - power on or some type of reset.
			 */
			if(r->sense[12] == 0x28 && r->sense[13] == 0)
				return 2;
			if(r->sense[12] == 0x29)
				return 2;
			return -1;
		case 0x02:		/* not ready */
			/*
			 * If no medium present, bail out.
			 * If unit is becoming ready, rather than not
			 * not ready, wait a little then poke it again. 				 */
			if(r->sense[12] == 0x3A)
				return 1;
			if(r->sense[12] != 0x04 || r->sense[13] != 0x01)
				return -1;

			while(waserror())
				;
			tsleep(&up->sleep, return0, 0, 500);
			poperror();
			scsitest(r);
			return 2;
		default:
			return -1;
		}
		return -1;
	case SDok:
		return 0;
	}
	return -1;
}


static int
ataverify(SDunit* unit)
{
	SDreq *r;
	int i, status;
	uchar *inquiry;

	if((r = malloc(sizeof(SDreq))) == nil)
		return 0;
	if((inquiry = sdmalloc(sizeof(unit->inquiry))) == nil){
		free(r);
		return 0;
	}
	r->unit = unit;
	r->lun = 0;		/* ??? */

	memset(unit->inquiry, 0, sizeof(unit->inquiry));
	r->write = 0;
	r->cmd[0] = 0x12;
	r->cmd[1] = r->lun<<5;
	r->cmd[4] = sizeof(unit->inquiry)-1;
	r->clen = 6;
	r->data = inquiry;
	r->dlen = sizeof(unit->inquiry)-1;
	r->flags = 0;

	r->status = ~0;
	if(unit->dev->ifc->rio(r) != SDok){
		free(r);
		return 0;
	}
	memmove(unit->inquiry, inquiry, r->dlen);
	free(inquiry); 

	SET(status);
	for(i = 0; i < 3; i++){
		while((status = scsitest(r)) == SDbusy)
			;
		if(status == SDok || status != SDcheck)
			break;
		if(!(r->flags & SDvalidsense))
			break;
		if((r->sense[2] & 0x0F) != 0x02)
			continue;
		/*
		 * Unit is 'not ready'.
		 * If it needs an initialising command, set status
		 * so it will be spun-up below.
		 * If there's no medium, that's OK too, but don't
		 * try to spin it up.
		 */
		if(r->sense[12] == 0x04 && r->sense[13] == 0x02){
			status = SDok;
			break;
		}
		if(r->sense[12] == 0x3A)
			break;
	}

	if(status == SDok){
		/*
		 * Try to ensure a direct-access device is spinning.
		 * Don't wait for completion, ignore the result.
		 */
		if((unit->inquiry[0] & 0x1F) == 0){
			memset(r->cmd, 0, sizeof(r->cmd));
			r->write = 0;
			r->cmd[0] = 0x1B;
			r->cmd[1] = (r->lun<<5)|0x01;
			r->cmd[4] = 1;
			r->clen = 6;
			r->data = nil;
			r->dlen = 0;
			r->flags = 0;

			r->status = ~0;
			unit->dev->ifc->rio(r);
		}
	}
	free(r);

	if(status == SDok || status == SDcheck)
		return 1;
	return 0;
}

static int
ataonline(SDunit* unit)
{
	SDreq *r;
	uchar *p;
	int ok, retries;

	if((r = malloc(sizeof(SDreq))) == nil)
		return 0;
	if((p = sdmalloc(8)) == nil){
		free(r);
		return 0;
	}

	ok = 0;

	r->unit = unit;
	r->lun = 0;				/* ??? */
	for(retries = 0; retries < 10; retries++){
		/*
		 * Read-capacity is mandatory for DA, WORM, CD-ROM and
		 * MO. It may return 'not ready' if type DA is not
		 * spun up, type MO or type CD-ROM are not loaded or just
		 * plain slow getting their act together after a reset.
		 */
		r->write = 0;
		memset(r->cmd, 0, sizeof(r->cmd));
		r->cmd[0] = 0x25;
		r->cmd[1] = r->lun<<5;
		r->clen = 10;
		r->data = p;
		r->dlen = 8;
		r->flags = 0;
	
		r->status = ~0;
		switch(scsirio(r)){
		default:
			break;
		case 0:
			unit->sectors = (p[0]<<24)|(p[1]<<16)|(p[2]<<8)|p[3];
			/*
			 * Read-capacity returns the LBA of the last sector,
			 * therefore the number of sectors must be incremented.
			 */
			unit->sectors++;
			unit->secsize = (p[4]<<24)|(p[5]<<16)|(p[6]<<8)|p[7];

			/*
			 * Some ATAPI CD readers lie about the block size.
			 * Since we don't read audio via this interface
			 * it's okay to always fudge this.
			 */
			if(unit->secsize == 2352)
				unit->secsize = 2048;
			ok = 1;
			break;
		case 1:
			ok = 1;
			break;
		case 2:
			continue;
		}
		break;
	}
	free(p);
	free(r);

	if(ok)
		return ok+retries;
	else
		return 0;
}

static long
atabio(SDunit* unit, int lun, int write, void* data, long nb, long bno)
{
	SDreq *r;
	long rlen;

	if((r = malloc(sizeof(SDreq))) == nil)
		error(Enomem);
	r->unit = unit;
	r->lun = lun;
again:
	r->write = write;
	if(write == 0)
		r->cmd[0] = 0x28;
	else
		r->cmd[0] = 0x2A;
	r->cmd[1] = (lun<<5);
	r->cmd[2] = bno>>24;
	r->cmd[3] = bno>>16;
	r->cmd[4] = bno>>8;
	r->cmd[5] = bno;
	r->cmd[6] = 0;
	r->cmd[7] = nb>>8;
	r->cmd[8] = nb;
	r->cmd[9] = 0;
	r->clen = 10;
	r->data = data;
	r->dlen = nb*unit->secsize;
	r->flags = 0;

	r->status = ~0;
	switch(scsirio(r)){
	default:
		rlen = -1;
		break;
	case 0:
		rlen = r->rlen;
		break;
	case 2:
		rlen = -1;
		if(!(r->flags & SDvalidsense))
			break;
		switch(r->sense[2] & 0x0F){
		default:
			break;
		case 0x06:		/* check condition */
			/*
			 * Check for a removeable media change.
			 * If so, mark it by zapping the geometry info
			 * to force an online request.
			 */
			if(r->sense[12] != 0x28 || r->sense[13] != 0)
				break;
			if(unit->inquiry[1] & 0x80)
				unit->sectors = 0;
			break;
		case 0x02:		/* not ready */
			/*
			 * If unit is becoming ready,
			 * rather than not not ready, try again.
			 */
			if(r->sense[12] == 0x04 && r->sense[13] == 0x01)
				goto again;
			break;
		}
		break;
	}
	free(r);

	return rlen;
}


struct Try {
	int p;
	int c;
} tries[] = {
		   { 0, 0x0c },
		   { 0, 0 }, 
};

static SDev*
ataprobew(DevConf *cf)
{
	int	cmdport;
	int	ctlport;
	int	irq;
	SDev*	rc;
	struct Try *try;

	rc = nil;
	for (try = &tries[0]; try->p != 0 || try->c != 0; try++){
		ataitype = cf->itype;
		atairq  = cf->intnum;
		cmdport = cf->ports[0].port + try->p;
		ctlport = cmdport + try->c;
		irq = cf->intnum;
		rc = ataprobe(cmdport, ctlport, irq);
		if (rc)
			break;
	}
	return rc;
}

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

	ctlr = sdev->ctlr;

	if (ctlr->drive[0])
		free(ctlr->drive[0]);
	if (ctlr->drive[1])
		free(ctlr->drive[1]);
	if (sdev->name)
		free(sdev->name);
	if (sdev->unitflg)
		free(sdev->unitflg);
	if (sdev->unit)
		free(sdev->unit);
	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);
}


SDifc sdataifc = {
	"ata",				/* name */

	nil,				/* pnp */
	atalegacy,			/* legacy */
	ataenable,			/* enable */
	nil,				/* disable */

	ataverify,			/* verify */
	ataonline,			/* online */
	atario,				/* rio */
	atarctl,			/* rctl */
	atawctl,			/* wctl */

	atabio,				/* bio */
	ataprobew,			/* probew */
	ataclear,			/* clear */
	atastat,			/* stat */
};