scsi_scan.c

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				if (shpnt->this_id != order_dev) {

					/*
					 * We need the for so our continue, etc. work fine. We put this in
					 * a variable so that we can override it during the scan if we
					 * detect a device *KNOWN* to have multiple logical units.
					 */
					max_dev_lun = (max_scsi_luns < shpnt->max_lun ?
					 max_scsi_luns : shpnt->max_lun);
					sparse_lun = 0;
					for (lun = 0; lun < max_dev_lun; ++lun) {
						if (!scan_scsis_single(channel, order_dev, lun, &max_dev_lun,
								       &sparse_lun, &SDpnt, shpnt,
							     scsi_result)
						    && !sparse_lun)
							break;	/* break means don't probe further for luns!=0 */
					}	/* for lun ends */
				}	/* if this_id != id ends */
			}	/* for dev ends */
		}		/* for channel ends */
	}			/* if/else hardcoded */

      leave:

	{			/* Unchain SRpnt from host_queue */
		Scsi_Device *prev, *next;
		Scsi_Device *dqptr;

		for (dqptr = shpnt->host_queue; dqptr != SDpnt; dqptr = dqptr->next)
			continue;
		if (dqptr) {
			prev = dqptr->prev;
			next = dqptr->next;
			if (prev)
				prev->next = next;
			else
				shpnt->host_queue = next;
			if (next)
				next->prev = prev;
		}
	}

	/* Last device block does not exist.  Free memory. */
	if (SDpnt != NULL) {
		blk_cleanup_queue(&SDpnt->request_queue);
		kfree((char *) SDpnt);
	}

	/* If we allocated a buffer so we could do DMA, free it now */
	if (scsi_result != &scsi_result0[0] && scsi_result != NULL) {
		kfree(scsi_result);
	} {
		Scsi_Device *sdev;
		Scsi_Cmnd *scmd;

		SCSI_LOG_SCAN_BUS(4, printk("Host status for host %p:\n", shpnt));
		for (sdev = shpnt->host_queue; sdev; sdev = sdev->next) {
			SCSI_LOG_SCAN_BUS(4, printk("Device %d %p: ", sdev->id, sdev));
			for (scmd = sdev->device_queue; scmd; scmd = scmd->next) {
				SCSI_LOG_SCAN_BUS(4, printk("%p ", scmd));
			}
			SCSI_LOG_SCAN_BUS(4, printk("\n"));
		}
	}
}

/*
 * The worker for scan_scsis.
 * Returning 0 means Please don't ask further for lun!=0, 1 means OK go on.
 * Global variables used : scsi_devices(linked list)
 */
static int scan_scsis_single(int channel, int dev, int lun, int *max_dev_lun,
	       int *sparse_lun, Scsi_Device ** SDpnt2, 
		      struct Scsi_Host *shpnt, char *scsi_result)
{
	char devname[64];
	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
	struct Scsi_Device_Template *sdtpnt;
	Scsi_Device *SDtail, *SDpnt = *SDpnt2;
	Scsi_Request * SRpnt;
	int bflags, type = -1;
	extern devfs_handle_t scsi_devfs_handle;

	SDpnt->host = shpnt;
	SDpnt->id = dev;
	SDpnt->lun = lun;
	SDpnt->channel = channel;
	SDpnt->online = TRUE;

	scsi_build_commandblocks(SDpnt);
 
	/* Some low level driver could use device->type (DB) */
	SDpnt->type = -1;

	/*
	 * Assume that the device will have handshaking problems, and then fix this
	 * field later if it turns out it doesn't
	 */
	SDpnt->borken = 1;
	SDpnt->was_reset = 0;
	SDpnt->expecting_cc_ua = 0;
	SDpnt->starved = 0;

	SRpnt = scsi_allocate_request(SDpnt);

	/*
	 * We used to do a TEST_UNIT_READY before the INQUIRY but that was 
	 * not really necessary.  Spec recommends using INQUIRY to scan for
	 * devices (and TEST_UNIT_READY to poll for media change). - Paul G.
	 */

	SCSI_LOG_SCAN_BUS(3, printk("scsi: performing INQUIRY\n"));
	/*
	 * Build an INQUIRY command block.
	 */
	scsi_cmd[0] = INQUIRY;
	scsi_cmd[1] = (lun << 5) & 0xe0;
	scsi_cmd[2] = 0;
	scsi_cmd[3] = 0;
	scsi_cmd[4] = 255;
	scsi_cmd[5] = 0;
	SRpnt->sr_cmd_len = 0;
	SRpnt->sr_data_direction = SCSI_DATA_READ;

	scsi_wait_req (SRpnt, (void *) scsi_cmd,
	          (void *) scsi_result,
	          256, SCSI_TIMEOUT+4*HZ, 3);

	SCSI_LOG_SCAN_BUS(3, printk("scsi: INQUIRY %s with code 0x%x\n",
		SRpnt->sr_result ? "failed" : "successful", SRpnt->sr_result));

	if (SRpnt->sr_result) {
		scsi_release_request(SRpnt);
		return 0;	/* assume no peripheral if any sort of error */
	}

	/*
	 * Check the peripheral qualifier field - this tells us whether LUNS
	 * are supported here or not.
	 */
	if ((scsi_result[0] >> 5) == 3) {
		scsi_release_request(SRpnt);
		return 0;	/* assume no peripheral if any sort of error */
	}

	/*
	 * Get any flags for this device.  
	 */
	bflags = get_device_flags (scsi_result);


	 /*   The Toshiba ROM was "gender-changed" here as an inline hack.
	      This is now much more generic.
	      This is a mess: What we really want is to leave the scsi_result
	      alone, and just change the SDpnt structure. And the SDpnt is what
	      we want print_inquiry to print.  -- REW
	 */
	if (bflags & BLIST_ISDISK) {
		scsi_result[0] = TYPE_DISK;                                                
		scsi_result[1] |= 0x80;     /* removable */
	}

	if (bflags & BLIST_ISROM) {
		scsi_result[0] = TYPE_ROM;
		scsi_result[1] |= 0x80;     /* removable */
	}
    
	memcpy(SDpnt->vendor, scsi_result + 8, 8);
	memcpy(SDpnt->model, scsi_result + 16, 16);
	memcpy(SDpnt->rev, scsi_result + 32, 4);

	SDpnt->removable = (0x80 & scsi_result[1]) >> 7;
	/* Use the peripheral qualifier field to determine online/offline */
	if (((scsi_result[0] >> 5) & 7) == 1) 	SDpnt->online = FALSE;
	else SDpnt->online = TRUE;
	SDpnt->lockable = SDpnt->removable;
	SDpnt->changed = 0;
	SDpnt->access_count = 0;
	SDpnt->busy = 0;
	SDpnt->has_cmdblocks = 0;
	/*
	 * Currently, all sequential devices are assumed to be tapes, all random
	 * devices disk, with the appropriate read only flags set for ROM / WORM
	 * treated as RO.
	 */
	switch (type = (scsi_result[0] & 0x1f)) {
	case TYPE_TAPE:
	case TYPE_DISK:
	case TYPE_MOD:
	case TYPE_PROCESSOR:
	case TYPE_SCANNER:
	case TYPE_MEDIUM_CHANGER:
	case TYPE_ENCLOSURE:
	case TYPE_COMM:
		SDpnt->writeable = 1;
		break;
	case TYPE_WORM:
	case TYPE_ROM:
		SDpnt->writeable = 0;
		break;
	default:
		printk("scsi: unknown type %d\n", type);
	}

	SDpnt->device_blocked = FALSE;
	SDpnt->device_busy = 0;
	SDpnt->single_lun = 0;
	SDpnt->soft_reset =
	    (scsi_result[7] & 1) && ((scsi_result[3] & 7) == 2);
	SDpnt->random = (type == TYPE_TAPE) ? 0 : 1;
	SDpnt->type = (type & 0x1f);

	print_inquiry(scsi_result);

        sprintf (devname, "host%d/bus%d/target%d/lun%d",
                 SDpnt->host->host_no, SDpnt->channel, SDpnt->id, SDpnt->lun);
        if (SDpnt->de) printk ("DEBUG: dir: \"%s\" already exists\n", devname);
        else SDpnt->de = devfs_mk_dir (scsi_devfs_handle, devname, NULL);

	for (sdtpnt = scsi_devicelist; sdtpnt;
	     sdtpnt = sdtpnt->next)
		if (sdtpnt->detect)
			SDpnt->attached +=
			    (*sdtpnt->detect) (SDpnt);

	SDpnt->scsi_level = scsi_result[2] & 0x07;
	if (SDpnt->scsi_level >= 2 ||
	    (SDpnt->scsi_level == 1 &&
	     (scsi_result[3] & 0x0f) == 1))
		SDpnt->scsi_level++;

	/*
	 * Accommodate drivers that want to sleep when they should be in a polling
	 * loop.
	 */
	SDpnt->disconnect = 0;


	/*
	 * Set the tagged_queue flag for SCSI-II devices that purport to support
	 * tagged queuing in the INQUIRY data.
	 */
	SDpnt->tagged_queue = 0;
	if ((SDpnt->scsi_level >= SCSI_2) &&
	    (scsi_result[7] & 2) &&
	    !(bflags & BLIST_NOTQ)) {
		SDpnt->tagged_supported = 1;
		SDpnt->current_tag = 0;
	}
	/*
	 * Some revisions of the Texel CD ROM drives have handshaking problems when
	 * used with the Seagate controllers.  Before we know what type of device
	 * we're talking to, we assume it's borken and then change it here if it
	 * turns out that it isn't a TEXEL drive.
	 */
	if ((bflags & BLIST_BORKEN) == 0)
		SDpnt->borken = 0;

	/*
	 * If we want to only allow I/O to one of the luns attached to this device
	 * at a time, then we set this flag.
	 */
	if (bflags & BLIST_SINGLELUN)
		SDpnt->single_lun = 1;

	/*
	 * These devices need this "key" to unlock the devices so we can use it
	 */
	if ((bflags & BLIST_KEY) != 0) {
		printk("Unlocked floptical drive.\n");
		SDpnt->lockable = 0;
		scsi_cmd[0] = MODE_SENSE;
		scsi_cmd[1] = (lun << 5) & 0xe0;
		scsi_cmd[2] = 0x2e;
		scsi_cmd[3] = 0;
		scsi_cmd[4] = 0x2a;
		scsi_cmd[5] = 0;
		SRpnt->sr_cmd_len = 0;
		SRpnt->sr_data_direction = SCSI_DATA_READ;
		scsi_wait_req (SRpnt, (void *) scsi_cmd,
	        	(void *) scsi_result, 0x2a,
	        	SCSI_TIMEOUT, 3);
	}

	scsi_release_request(SRpnt);
	SRpnt = NULL;

	scsi_release_commandblocks(SDpnt);

	/*
	 * This device was already hooked up to the host in question,
	 * so at this point we just let go of it and it should be fine.  We do need to
	 * allocate a new one and attach it to the host so that we can further scan the bus.
	 */
	SDpnt = (Scsi_Device *) kmalloc(sizeof(Scsi_Device), GFP_ATOMIC);
	if (!SDpnt) {
		printk("scsi: scan_scsis_single: Cannot malloc\n");
		return 0;
	}
        memset(SDpnt, 0, sizeof(Scsi_Device));

	*SDpnt2 = SDpnt;
	SDpnt->queue_depth = 1;
	SDpnt->host = shpnt;
	SDpnt->online = TRUE;

	/*
	 * Register the queue for the device.  All I/O requests will come
	 * in through here.  We also need to register a pointer to
	 * ourselves, since the queue handler won't know what device
	 * the queue actually represents.   We could look it up, but it
	 * is pointless work.
	 */
	scsi_initialize_queue(SDpnt, shpnt);
	SDpnt->host = shpnt;
	initialize_merge_fn(SDpnt);

	/*
	 * Mark this device as online, or otherwise we won't be able to do much with it.
	 */
	SDpnt->online = TRUE;

        /*
         * Initialize the object that we will use to wait for command blocks.
         */
	init_waitqueue_head(&SDpnt->scpnt_wait);

	/*
	 * Since we just found one device, there had damn well better be one in the list
	 * already.
	 */
	if (shpnt->host_queue == NULL)
		panic("scan_scsis_single: Host queue == NULL\n");

	SDtail = shpnt->host_queue;
	while (SDtail->next) {
		SDtail = SDtail->next;
	}

	/* Add this device to the linked list at the end */
	SDtail->next = SDpnt;
	SDpnt->prev = SDtail;
	SDpnt->next = NULL;

	/*
	 * Some scsi devices cannot be polled for lun != 0 due to firmware bugs
	 */
	if (bflags & BLIST_NOLUN)
		return 0;	/* break; */

	/*
	 * If this device is known to support sparse multiple units, override the
	 * other settings, and scan all of them.
	 */
	if (bflags & BLIST_SPARSELUN) {
		*max_dev_lun = 8;
		*sparse_lun = 1;
		return 1;
	}
	/*
	 * If this device is known to support multiple units, override the other
	 * settings, and scan all of them.
	 */
	if (bflags & BLIST_FORCELUN) {
		*max_dev_lun = 8;
		return 1;
	}
	/*
	 * REGAL CDC-4X: avoid hang after LUN 4
	 */
	if (bflags & BLIST_MAX5LUN) {
		*max_dev_lun = 5;
		return 1;
	}

	/*
	 * We assume the device can't handle lun!=0 if: - it reports scsi-0
	 * (ANSI SCSI Revision 0) (old drives like MAXTOR XT-3280) or - it
	 * reports scsi-1 (ANSI SCSI Revision 1) and Response Data Format 0
	 */
	if (((scsi_result[2] & 0x07) == 0)
	    ||
	    ((scsi_result[2] & 0x07) == 1 &&
	     (scsi_result[3] & 0x0f) == 0))
		return 0;
	return 1;
}