tape_core.c

linux-2.6.15.6

		op = tape_op_verbose[request->op];
	else
		op = "---";
	DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
		  irb->scsw.dstat,irb->scsw.cstat);
	DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
	sptr = (unsigned int *) irb->ecw;
	DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
	DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
	DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
	DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
}

/*
 * I/O helper function. Adds the request to the request queue
 * and starts it if the tape is idle. Has to be called with
 * the device lock held.
 */
static inline int
__tape_start_request(struct tape_device *device, struct tape_request *request)
{
	int rc;

	switch (request->op) {
		case TO_MSEN:
		case TO_ASSIGN:
		case TO_UNASSIGN:
		case TO_READ_ATTMSG:
			if (device->tape_state == TS_INIT)
				break;
			if (device->tape_state == TS_UNUSED)
				break;
		default:
			if (device->tape_state == TS_BLKUSE)
				break;
			if (device->tape_state != TS_IN_USE)
				return -ENODEV;
	}

	/* Increase use count of device for the added request. */
	request->device = tape_get_device_reference(device);

	if (list_empty(&device->req_queue)) {
		/* No other requests are on the queue. Start this one. */
		rc = __tape_start_io(device, request);
		if (rc)
			return rc;

		DBF_LH(5, "Request %p added for execution.\n", request);
		list_add(&request->list, &device->req_queue);
	} else {
		DBF_LH(5, "Request %p add to queue.\n", request);
		request->status = TAPE_REQUEST_QUEUED;
		list_add_tail(&request->list, &device->req_queue);
	}
	return 0;
}

/*
 * Add the request to the request queue, try to start it if the
 * tape is idle. Return without waiting for end of i/o.
 */
int
tape_do_io_async(struct tape_device *device, struct tape_request *request)
{
	int rc;

	DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	/* Add request to request queue and try to start it. */
	rc = __tape_start_request(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	return rc;
}

/*
 * tape_do_io/__tape_wake_up
 * Add the request to the request queue, try to start it if the
 * tape is idle and wait uninterruptible for its completion.
 */
static void
__tape_wake_up(struct tape_request *request, void *data)
{
	request->callback = NULL;
	wake_up((wait_queue_head_t *) data);
}

int
tape_do_io(struct tape_device *device, struct tape_request *request)
{
	wait_queue_head_t wq;
	int rc;

	init_waitqueue_head(&wq);
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	/* Setup callback */
	request->callback = __tape_wake_up;
	request->callback_data = &wq;
	/* Add request to request queue and try to start it. */
	rc = __tape_start_request(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	if (rc)
		return rc;
	/* Request added to the queue. Wait for its completion. */
	wait_event(wq, (request->callback == NULL));
	/* Get rc from request */
	return request->rc;
}

/*
 * tape_do_io_interruptible/__tape_wake_up_interruptible
 * Add the request to the request queue, try to start it if the
 * tape is idle and wait uninterruptible for its completion.
 */
static void
__tape_wake_up_interruptible(struct tape_request *request, void *data)
{
	request->callback = NULL;
	wake_up_interruptible((wait_queue_head_t *) data);
}

int
tape_do_io_interruptible(struct tape_device *device,
			 struct tape_request *request)
{
	wait_queue_head_t wq;
	int rc;

	init_waitqueue_head(&wq);
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	/* Setup callback */
	request->callback = __tape_wake_up_interruptible;
	request->callback_data = &wq;
	rc = __tape_start_request(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	if (rc)
		return rc;
	/* Request added to the queue. Wait for its completion. */
	rc = wait_event_interruptible(wq, (request->callback == NULL));
	if (rc != -ERESTARTSYS)
		/* Request finished normally. */
		return request->rc;

	/* Interrupted by a signal. We have to stop the current request. */
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	rc = __tape_cancel_io(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	if (rc == 0) {
		/* Wait for the interrupt that acknowledges the halt. */
		do {
			rc = wait_event_interruptible(
				wq,
				(request->callback == NULL)
			);
		} while (rc != -ERESTARTSYS);

		DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
		rc = -ERESTARTSYS;
	}
	return rc;
}

/*
 * Tape interrupt routine, called from the ccw_device layer
 */
static void
__tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
{
	struct tape_device *device;
	struct tape_request *request;
	int rc;

	device = (struct tape_device *) cdev->dev.driver_data;
	if (device == NULL) {
		PRINT_ERR("could not get device structure for %s "
			  "in interrupt\n", cdev->dev.bus_id);
		return;
	}
	request = (struct tape_request *) intparm;

	DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);

	/* On special conditions irb is an error pointer */
	if (IS_ERR(irb)) {
		/* FIXME: What to do with the request? */
		switch (PTR_ERR(irb)) {
			case -ETIMEDOUT:
				PRINT_WARN("(%s): Request timed out\n",
					cdev->dev.bus_id);
			case -EIO:
				__tape_end_request(device, request, -EIO);
				break;
			default:
				PRINT_ERR("(%s): Unexpected i/o error %li\n",
					cdev->dev.bus_id,
					PTR_ERR(irb));
		}
		return;
	}

	/*
	 * If the condition code is not zero and the start function bit is
	 * still set, this is an deferred error and the last start I/O did
	 * not succeed. Restart the request now.
	 */
	if (irb->scsw.cc != 0 && (irb->scsw.fctl & SCSW_FCTL_START_FUNC)) {
		PRINT_WARN("(%s): deferred cc=%i. restaring\n",
			cdev->dev.bus_id,
			irb->scsw.cc);
		rc = __tape_start_io(device, request);
		if (rc)
			__tape_end_request(device, request, rc);
		return;
	}

	/* May be an unsolicited irq */
	if(request != NULL)
		request->rescnt = irb->scsw.count;

	if (irb->scsw.dstat != 0x0c) {
		/* Set the 'ONLINE' flag depending on sense byte 1 */
		if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
			device->tape_generic_status |= GMT_ONLINE(~0);
		else
			device->tape_generic_status &= ~GMT_ONLINE(~0);

		/*
		 * Any request that does not come back with channel end
		 * and device end is unusual. Log the sense data.
		 */
		DBF_EVENT(3,"-- Tape Interrupthandler --\n");
		tape_dump_sense_dbf(device, request, irb);
	} else {
		/* Upon normal completion the device _is_ online */
		device->tape_generic_status |= GMT_ONLINE(~0);
	}
	if (device->tape_state == TS_NOT_OPER) {
		DBF_EVENT(6, "tape:device is not operational\n");
		return;
	}

	/*
	 * Request that were canceled still come back with an interrupt.
	 * To detect these request the state will be set to TAPE_REQUEST_DONE.
	 */
	if(request != NULL && request->status == TAPE_REQUEST_DONE) {
		__tape_end_request(device, request, -EIO);
		return;
	}

	rc = device->discipline->irq(device, request, irb);
	/*
	 * rc < 0 : request finished unsuccessfully.
	 * rc == TAPE_IO_SUCCESS: request finished successfully.
	 * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
	 * rc == TAPE_IO_RETRY: request finished but needs another go.
	 * rc == TAPE_IO_STOP: request needs to get terminated.
	 */
	switch (rc) {
		case TAPE_IO_SUCCESS:
			/* Upon normal completion the device _is_ online */
			device->tape_generic_status |= GMT_ONLINE(~0);
			__tape_end_request(device, request, rc);
			break;
		case TAPE_IO_PENDING:
			break;
		case TAPE_IO_RETRY:
			rc = __tape_start_io(device, request);
			if (rc)
				__tape_end_request(device, request, rc);
			break;
		case TAPE_IO_STOP:
			rc = __tape_cancel_io(device, request);
			if (rc)
				__tape_end_request(device, request, rc);
			break;
		default:
			if (rc > 0) {
				DBF_EVENT(6, "xunknownrc\n");
				PRINT_ERR("Invalid return code from discipline "
				  	"interrupt function.\n");
				__tape_end_request(device, request, -EIO);
			} else {
				__tape_end_request(device, request, rc);
			}
			break;
	}
}

/*
 * Tape device open function used by tape_char & tape_block frontends.
 */
int
tape_open(struct tape_device *device)
{
	int rc;

	spin_lock(get_ccwdev_lock(device->cdev));
	if (device->tape_state == TS_NOT_OPER) {
		DBF_EVENT(6, "TAPE:nodev\n");
		rc = -ENODEV;
	} else if (device->tape_state == TS_IN_USE) {
		DBF_EVENT(6, "TAPE:dbusy\n");
		rc = -EBUSY;
	} else if (device->tape_state == TS_BLKUSE) {
		DBF_EVENT(6, "TAPE:dbusy\n");
		rc = -EBUSY;
	} else if (device->discipline != NULL &&
		   !try_module_get(device->discipline->owner)) {
		DBF_EVENT(6, "TAPE:nodisc\n");
		rc = -ENODEV;
	} else {
		tape_state_set(device, TS_IN_USE);
		rc = 0;
	}
	spin_unlock(get_ccwdev_lock(device->cdev));
	return rc;
}

/*
 * Tape device release function used by tape_char & tape_block frontends.
 */
int
tape_release(struct tape_device *device)
{
	spin_lock(get_ccwdev_lock(device->cdev));
	if (device->tape_state == TS_IN_USE)
		tape_state_set(device, TS_UNUSED);
	module_put(device->discipline->owner);
	spin_unlock(get_ccwdev_lock(device->cdev));
	return 0;
}

/*
 * Execute a magnetic tape command a number of times.
 */
int
tape_mtop(struct tape_device *device, int mt_op, int mt_count)
{
	tape_mtop_fn fn;
	int rc;

	DBF_EVENT(6, "TAPE:mtio\n");
	DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
	DBF_EVENT(6, "TAPE:arg:	 %x\n", mt_count);

	if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
		return -EINVAL;
	fn = device->discipline->mtop_array[mt_op];
	if (fn == NULL)
		return -EINVAL;

	/* We assume that the backends can handle count up to 500. */
	if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
	    mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
		rc = 0;
		for (; mt_count > 500; mt_count -= 500)
			if ((rc = fn(device, 500)) != 0)
				break;
		if (rc == 0)
			rc = fn(device, mt_count);
	} else
		rc = fn(device, mt_count);
	return rc;

}

/*
 * Tape init function.
 */
static int
tape_init (void)
{
	TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
	debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
#ifdef DBF_LIKE_HELL
	debug_set_level(TAPE_DBF_AREA, 6);
#endif
	DBF_EVENT(3, "tape init: ($Revision: 1.54 $)\n");
	tape_proc_init();
	tapechar_init ();
	tapeblock_init ();
	return 0;
}

/*
 * Tape exit function.
 */
static void
tape_exit(void)
{
	DBF_EVENT(6, "tape exit\n");

	/* Get rid of the frontends */
	tapechar_exit();
	tapeblock_exit();
	tape_proc_cleanup();
	debug_unregister (TAPE_DBF_AREA);
}

MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
	      "Michael Holzheu ([e-mail],[e-mail])");
MODULE_DESCRIPTION("Linux on zSeries channel attached "
		   "tape device driver ($Revision: 1.54 $)");
MODULE_LICENSE("GPL");

module_init(tape_init);
module_exit(tape_exit);

EXPORT_SYMBOL(tape_generic_remove);
EXPORT_SYMBOL(tape_generic_probe);
EXPORT_SYMBOL(tape_generic_online);
EXPORT_SYMBOL(tape_generic_offline);
EXPORT_SYMBOL(tape_put_device);
EXPORT_SYMBOL(tape_get_device_reference);
EXPORT_SYMBOL(tape_state_verbose);
EXPORT_SYMBOL(tape_op_verbose);
EXPORT_SYMBOL(tape_state_set);
EXPORT_SYMBOL(tape_med_state_set);
EXPORT_SYMBOL(tape_alloc_request);
EXPORT_SYMBOL(tape_free_request);
EXPORT_SYMBOL(tape_dump_sense);
EXPORT_SYMBOL(tape_dump_sense_dbf);
EXPORT_SYMBOL(tape_do_io);
EXPORT_SYMBOL(tape_do_io_async);
EXPORT_SYMBOL(tape_do_io_interruptible);
EXPORT_SYMBOL(tape_mtop);