Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1233 insertions, 0 deletions

diff --git a/drivers/s390/char/tape_34xx.c b/drivers/s390/char/tape_34xx.c
new file mode 100644
index 000000000..6d73ee3f8
--- /dev/null
+++ b/drivers/s390/char/tape_34xx.c
@@ -0,0 +1,1233 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    tape device discipline for 3480/3490 tapes.
+ *
+ *    Copyright IBM Corp. 2001, 2009
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
+ *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "tape_34xx"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+
+#define TAPE_DBF_AREA	tape_34xx_dbf
+
+#include "tape.h"
+#include "tape_std.h"
+
+/*
+ * Pointer to debug area.
+ */
+debug_info_t *TAPE_DBF_AREA = NULL;
+EXPORT_SYMBOL(TAPE_DBF_AREA);
+
+#define TAPE34XX_FMT_3480	0
+#define TAPE34XX_FMT_3480_2_XF	1
+#define TAPE34XX_FMT_3480_XF	2
+
+struct tape_34xx_block_id {
+	unsigned int	wrap		: 1;
+	unsigned int	segment		: 7;
+	unsigned int	format		: 2;
+	unsigned int	block		: 22;
+};
+
+/*
+ * A list of block ID's is used to faster seek blocks.
+ */
+struct tape_34xx_sbid {
+	struct list_head		list;
+	struct tape_34xx_block_id	bid;
+};
+
+static void tape_34xx_delete_sbid_from(struct tape_device *, int);
+
+/*
+ * Medium sense for 34xx tapes. There is no 'real' medium sense call.
+ * So we just do a normal sense.
+ */
+static void __tape_34xx_medium_sense(struct tape_request *request)
+{
+	struct tape_device *device = request->device;
+	unsigned char *sense;
+
+	if (request->rc == 0) {
+		sense = request->cpdata;
+
+		/*
+		 * This isn't quite correct. But since INTERVENTION_REQUIRED
+		 * means that the drive is 'neither ready nor on-line' it is
+		 * only slightly inaccurate to say there is no tape loaded if
+		 * the drive isn't online...
+		 */
+		if (sense[0] & SENSE_INTERVENTION_REQUIRED)
+			tape_med_state_set(device, MS_UNLOADED);
+		else
+			tape_med_state_set(device, MS_LOADED);
+
+		if (sense[1] & SENSE_WRITE_PROTECT)
+			device->tape_generic_status |= GMT_WR_PROT(~0);
+		else
+			device->tape_generic_status &= ~GMT_WR_PROT(~0);
+	} else
+		DBF_EVENT(4, "tape_34xx: medium sense failed with rc=%d\n",
+			request->rc);
+	tape_free_request(request);
+}
+
+static int tape_34xx_medium_sense(struct tape_device *device)
+{
+	struct tape_request *request;
+	int rc;
+
+	request = tape_alloc_request(1, 32);
+	if (IS_ERR(request)) {
+		DBF_EXCEPTION(6, "MSEN fail\n");
+		return PTR_ERR(request);
+	}
+
+	request->op = TO_MSEN;
+	tape_ccw_end(request->cpaddr, SENSE, 32, request->cpdata);
+	rc = tape_do_io_interruptible(device, request);
+	__tape_34xx_medium_sense(request);
+	return rc;
+}
+
+static void tape_34xx_medium_sense_async(struct tape_device *device)
+{
+	struct tape_request *request;
+
+	request = tape_alloc_request(1, 32);
+	if (IS_ERR(request)) {
+		DBF_EXCEPTION(6, "MSEN fail\n");
+		return;
+	}
+
+	request->op = TO_MSEN;
+	tape_ccw_end(request->cpaddr, SENSE, 32, request->cpdata);
+	request->callback = (void *) __tape_34xx_medium_sense;
+	request->callback_data = NULL;
+	tape_do_io_async(device, request);
+}
+
+struct tape_34xx_work {
+	struct tape_device	*device;
+	enum tape_op		 op;
+	struct work_struct	 work;
+};
+
+/*
+ * These functions are currently used only to schedule a medium_sense for
+ * later execution. This is because we get an interrupt whenever a medium
+ * is inserted but cannot call tape_do_io* from an interrupt context.
+ * Maybe that's useful for other actions we want to start from the
+ * interrupt handler.
+ * Note: the work handler is called by the system work queue. The tape
+ * commands started by the handler need to be asynchrounous, otherwise
+ * a deadlock can occur e.g. in case of a deferred cc=1 (see __tape_do_irq).
+ */
+static void
+tape_34xx_work_handler(struct work_struct *work)
+{
+	struct tape_34xx_work *p =
+		container_of(work, struct tape_34xx_work, work);
+	struct tape_device *device = p->device;
+
+	switch(p->op) {
+		case TO_MSEN:
+			tape_34xx_medium_sense_async(device);
+			break;
+		default:
+			DBF_EVENT(3, "T34XX: internal error: unknown work\n");
+	}
+	tape_put_device(device);
+	kfree(p);
+}
+
+static int
+tape_34xx_schedule_work(struct tape_device *device, enum tape_op op)
+{
+	struct tape_34xx_work *p;
+
+	if ((p = kzalloc(sizeof(*p), GFP_ATOMIC)) == NULL)
+		return -ENOMEM;
+
+	INIT_WORK(&p->work, tape_34xx_work_handler);
+
+	p->device = tape_get_device(device);
+	p->op     = op;
+
+	schedule_work(&p->work);
+	return 0;
+}
+
+/*
+ * Done Handler is called when dev stat = DEVICE-END (successful operation)
+ */
+static inline int
+tape_34xx_done(struct tape_request *request)
+{
+	DBF_EVENT(6, "%s done\n", tape_op_verbose[request->op]);
+
+	switch (request->op) {
+		case TO_DSE:
+		case TO_RUN:
+		case TO_WRI:
+		case TO_WTM:
+		case TO_ASSIGN:
+		case TO_UNASSIGN:
+			tape_34xx_delete_sbid_from(request->device, 0);
+			break;
+		default:
+			;
+	}
+	return TAPE_IO_SUCCESS;
+}
+
+static inline int
+tape_34xx_erp_failed(struct tape_request *request, int rc)
+{
+	DBF_EVENT(3, "Error recovery failed for %s (RC=%d)\n",
+		  tape_op_verbose[request->op], rc);
+	return rc;
+}
+
+static inline int
+tape_34xx_erp_succeeded(struct tape_request *request)
+{
+	DBF_EVENT(3, "Error Recovery successful for %s\n",
+		  tape_op_verbose[request->op]);
+	return tape_34xx_done(request);
+}
+
+static inline int
+tape_34xx_erp_retry(struct tape_request *request)
+{
+	DBF_EVENT(3, "xerp retr %s\n", tape_op_verbose[request->op]);
+	return TAPE_IO_RETRY;
+}
+
+/*
+ * This function is called, when no request is outstanding and we get an
+ * interrupt
+ */
+static int
+tape_34xx_unsolicited_irq(struct tape_device *device, struct irb *irb)
+{
+	if (irb->scsw.cmd.dstat == 0x85) { /* READY */
+		/* A medium was inserted in the drive. */
+		DBF_EVENT(6, "xuud med\n");
+		tape_34xx_delete_sbid_from(device, 0);
+		tape_34xx_schedule_work(device, TO_MSEN);
+	} else {
+		DBF_EVENT(3, "unsol.irq! dev end: %08x\n", device->cdev_id);
+		tape_dump_sense_dbf(device, NULL, irb);
+	}
+	return TAPE_IO_SUCCESS;
+}
+
+/*
+ * Read Opposite Error Recovery Function:
+ * Used, when Read Forward does not work
+ */
+static int
+tape_34xx_erp_read_opposite(struct tape_device *device,
+			    struct tape_request *request)
+{
+	if (request->op == TO_RFO) {
+		/*
+		 * We did read forward, but the data could not be read
+		 * *correctly*. We transform the request to a read backward
+		 * and try again.
+		 */
+		tape_std_read_backward(device, request);
+		return tape_34xx_erp_retry(request);
+	}
+
+	/*
+	 * We tried to read forward and backward, but hat no
+	 * success -> failed.
+	 */
+	return tape_34xx_erp_failed(request, -EIO);
+}
+
+static int
+tape_34xx_erp_bug(struct tape_device *device, struct tape_request *request,
+		  struct irb *irb, int no)
+{
+	if (request->op != TO_ASSIGN) {
+		dev_err(&device->cdev->dev, "An unexpected condition %d "
+			"occurred in tape error recovery\n", no);
+		tape_dump_sense_dbf(device, request, irb);
+	}
+	return tape_34xx_erp_failed(request, -EIO);
+}
+
+/*
+ * Handle data overrun between cu and drive. The channel speed might
+ * be too slow.
+ */
+static int
+tape_34xx_erp_overrun(struct tape_device *device, struct tape_request *request,
+		      struct irb *irb)
+{
+	if (irb->ecw[3] == 0x40) {
+		dev_warn (&device->cdev->dev, "A data overrun occurred between"
+			" the control unit and tape unit\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	}
+	return tape_34xx_erp_bug(device, request, irb, -1);
+}
+
+/*
+ * Handle record sequence error.
+ */
+static int
+tape_34xx_erp_sequence(struct tape_device *device,
+		       struct tape_request *request, struct irb *irb)
+{
+	if (irb->ecw[3] == 0x41) {
+		/*
+		 * cu detected incorrect block-id sequence on tape.
+		 */
+		dev_warn (&device->cdev->dev, "The block ID sequence on the "
+			"tape is incorrect\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	}
+	/*
+	 * Record sequence error bit is set, but erpa does not
+	 * show record sequence error.
+	 */
+	return tape_34xx_erp_bug(device, request, irb, -2);
+}
+
+/*
+ * This function analyses the tape's sense-data in case of a unit-check.
+ * If possible, it tries to recover from the error. Else the user is
+ * informed about the problem.
+ */
+static int
+tape_34xx_unit_check(struct tape_device *device, struct tape_request *request,
+		     struct irb *irb)
+{
+	int inhibit_cu_recovery;
+	__u8* sense;
+
+	inhibit_cu_recovery = (*device->modeset_byte & 0x80) ? 1 : 0;
+	sense = irb->ecw;
+
+	if (
+		sense[0] & SENSE_COMMAND_REJECT &&
+		sense[1] & SENSE_WRITE_PROTECT
+	) {
+		if (
+			request->op == TO_DSE ||
+			request->op == TO_WRI ||
+			request->op == TO_WTM
+		) {
+			/* medium is write protected */
+			return tape_34xx_erp_failed(request, -EACCES);
+		} else {
+			return tape_34xx_erp_bug(device, request, irb, -3);
+		}
+	}
+
+	/*
+	 * Special cases for various tape-states when reaching
+	 * end of recorded area
+	 *
+	 * FIXME: Maybe a special case of the special case:
+	 *        sense[0] == SENSE_EQUIPMENT_CHECK &&
+	 *        sense[1] == SENSE_DRIVE_ONLINE    &&
+	 *        sense[3] == 0x47 (Volume Fenced)
+	 *
+	 *        This was caused by continued FSF or FSR after an
+	 *        'End Of Data'.
+	 */
+	if ((
+		sense[0] == SENSE_DATA_CHECK      ||
+		sense[0] == SENSE_EQUIPMENT_CHECK ||
+		sense[0] == SENSE_EQUIPMENT_CHECK + SENSE_DEFERRED_UNIT_CHECK
+	) && (
+		sense[1] == SENSE_DRIVE_ONLINE ||
+		sense[1] == SENSE_BEGINNING_OF_TAPE + SENSE_WRITE_MODE
+	)) {
+		switch (request->op) {
+		/*
+		 * sense[0] == SENSE_DATA_CHECK   &&
+		 * sense[1] == SENSE_DRIVE_ONLINE
+		 * sense[3] == 0x36 (End Of Data)
+		 *
+		 * Further seeks might return a 'Volume Fenced'.
+		 */
+		case TO_FSF:
+		case TO_FSB:
+			/* Trying to seek beyond end of recorded area */
+			return tape_34xx_erp_failed(request, -ENOSPC);
+		case TO_BSB:
+			return tape_34xx_erp_retry(request);
+
+		/*
+		 * sense[0] == SENSE_DATA_CHECK   &&
+		 * sense[1] == SENSE_DRIVE_ONLINE &&
+		 * sense[3] == 0x36 (End Of Data)
+		 */
+		case TO_LBL:
+			/* Block could not be located. */
+			tape_34xx_delete_sbid_from(device, 0);
+			return tape_34xx_erp_failed(request, -EIO);
+
+		case TO_RFO:
+			/* Read beyond end of recorded area -> 0 bytes read */
+			return tape_34xx_erp_failed(request, 0);
+
+		/*
+		 * sense[0] == SENSE_EQUIPMENT_CHECK &&
+		 * sense[1] == SENSE_DRIVE_ONLINE    &&
+		 * sense[3] == 0x38 (Physical End Of Volume)
+		 */
+		case TO_WRI:
+			/* Writing at physical end of volume */
+			return tape_34xx_erp_failed(request, -ENOSPC);
+		default:
+			return tape_34xx_erp_failed(request, 0);
+		}
+	}
+
+	/* Sensing special bits */
+	if (sense[0] & SENSE_BUS_OUT_CHECK)
+		return tape_34xx_erp_retry(request);
+
+	if (sense[0] & SENSE_DATA_CHECK) {
+		/*
+		 * hardware failure, damaged tape or improper
+		 * operating conditions
+		 */
+		switch (sense[3]) {
+		case 0x23:
+			/* a read data check occurred */
+			if ((sense[2] & SENSE_TAPE_SYNC_MODE) ||
+			    inhibit_cu_recovery)
+				// data check is not permanent, may be
+				// recovered. We always use async-mode with
+				// cu-recovery, so this should *never* happen.
+				return tape_34xx_erp_bug(device, request,
+							 irb, -4);
+
+			/* data check is permanent, CU recovery has failed */
+			dev_warn (&device->cdev->dev, "A read error occurred "
+				"that cannot be recovered\n");
+			return tape_34xx_erp_failed(request, -EIO);
+		case 0x25:
+			// a write data check occurred
+			if ((sense[2] & SENSE_TAPE_SYNC_MODE) ||
+			    inhibit_cu_recovery)
+				// data check is not permanent, may be
+				// recovered. We always use async-mode with
+				// cu-recovery, so this should *never* happen.
+				return tape_34xx_erp_bug(device, request,
+							 irb, -5);
+
+			// data check is permanent, cu-recovery has failed
+			dev_warn (&device->cdev->dev, "A write error on the "
+				"tape cannot be recovered\n");
+			return tape_34xx_erp_failed(request, -EIO);
+		case 0x26:
+			/* Data Check (read opposite) occurred. */
+			return tape_34xx_erp_read_opposite(device, request);
+		case 0x28:
+			/* ID-Mark at tape start couldn't be written */
+			dev_warn (&device->cdev->dev, "Writing the ID-mark "
+				"failed\n");
+			return tape_34xx_erp_failed(request, -EIO);
+		case 0x31:
+			/* Tape void. Tried to read beyond end of device. */
+			dev_warn (&device->cdev->dev, "Reading the tape beyond"
+				" the end of the recorded area failed\n");
+			return tape_34xx_erp_failed(request, -ENOSPC);
+		case 0x41:
+			/* Record sequence error. */
+			dev_warn (&device->cdev->dev, "The tape contains an "
+				"incorrect block ID sequence\n");
+			return tape_34xx_erp_failed(request, -EIO);
+		default:
+			/* all data checks for 3480 should result in one of
+			 * the above erpa-codes. For 3490, other data-check
+			 * conditions do exist. */
+			if (device->cdev->id.driver_info == tape_3480)
+				return tape_34xx_erp_bug(device, request,
+							 irb, -6);
+		}
+	}
+
+	if (sense[0] & SENSE_OVERRUN)
+		return tape_34xx_erp_overrun(device, request, irb);
+
+	if (sense[1] & SENSE_RECORD_SEQUENCE_ERR)
+		return tape_34xx_erp_sequence(device, request, irb);
+
+	/* Sensing erpa codes */
+	switch (sense[3]) {
+	case 0x00:
+		/* Unit check with erpa code 0. Report and ignore. */
+		return TAPE_IO_SUCCESS;
+	case 0x21:
+		/*
+		 * Data streaming not operational. CU will switch to
+		 * interlock mode. Reissue the command.
+		 */
+		return tape_34xx_erp_retry(request);
+	case 0x22:
+		/*
+		 * Path equipment check. Might be drive adapter error, buffer
+		 * error on the lower interface, internal path not usable,
+		 * or error during cartridge load.
+		 */
+		dev_warn (&device->cdev->dev, "A path equipment check occurred"
+			" for the tape device\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x24:
+		/*
+		 * Load display check. Load display was command was issued,
+		 * but the drive is displaying a drive check message. Can
+		 * be threated as "device end".
+		 */
+		return tape_34xx_erp_succeeded(request);
+	case 0x27:
+		/*
+		 * Command reject. May indicate illegal channel program or
+		 * buffer over/underrun. Since all channel programs are
+		 * issued by this driver and ought be correct, we assume a
+		 * over/underrun situation and retry the channel program.
+		 */
+		return tape_34xx_erp_retry(request);
+	case 0x29:
+		/*
+		 * Function incompatible. Either the tape is idrc compressed
+		 * but the hardware isn't capable to do idrc, or a perform
+		 * subsystem func is issued and the CU is not on-line.
+		 */
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x2a:
+		/*
+		 * Unsolicited environmental data. An internal counter
+		 * overflows, we can ignore this and reissue the cmd.
+		 */
+		return tape_34xx_erp_retry(request);
+	case 0x2b:
+		/*
+		 * Environmental data present. Indicates either unload
+		 * completed ok or read buffered log command completed ok.
+		 */
+		if (request->op == TO_RUN) {
+			/* Rewind unload completed ok. */
+			tape_med_state_set(device, MS_UNLOADED);
+			return tape_34xx_erp_succeeded(request);
+		}
+		/* tape_34xx doesn't use read buffered log commands. */
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	case 0x2c:
+		/*
+		 * Permanent equipment check. CU has tried recovery, but
+		 * did not succeed.
+		 */
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x2d:
+		/* Data security erase failure. */
+		if (request->op == TO_DSE)
+			return tape_34xx_erp_failed(request, -EIO);
+		/* Data security erase failure, but no such command issued. */
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	case 0x2e:
+		/*
+		 * Not capable. This indicates either that the drive fails
+		 * reading the format id mark or that that format specified
+		 * is not supported by the drive.
+		 */
+		dev_warn (&device->cdev->dev, "The tape unit cannot process "
+			"the tape format\n");
+		return tape_34xx_erp_failed(request, -EMEDIUMTYPE);
+	case 0x30:
+		/* The medium is write protected. */
+		dev_warn (&device->cdev->dev, "The tape medium is write-"
+			"protected\n");
+		return tape_34xx_erp_failed(request, -EACCES);
+	case 0x32:
+		// Tension loss. We cannot recover this, it's an I/O error.
+		dev_warn (&device->cdev->dev, "The tape does not have the "
+			"required tape tension\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x33:
+		/*
+		 * Load Failure. The cartridge was not inserted correctly or
+		 * the tape is not threaded correctly.
+		 */
+		dev_warn (&device->cdev->dev, "The tape unit failed to load"
+			" the cartridge\n");
+		tape_34xx_delete_sbid_from(device, 0);
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x34:
+		/*
+		 * Unload failure. The drive cannot maintain tape tension
+		 * and control tape movement during an unload operation.
+		 */
+		dev_warn (&device->cdev->dev, "Automatic unloading of the tape"
+			" cartridge failed\n");
+		if (request->op == TO_RUN)
+			return tape_34xx_erp_failed(request, -EIO);
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	case 0x35:
+		/*
+		 * Drive equipment check. One of the following:
+		 * - cu cannot recover from a drive detected error
+		 * - a check code message is shown on drive display
+		 * - the cartridge loader does not respond correctly
+		 * - a failure occurs during an index, load, or unload cycle
+		 */
+		dev_warn (&device->cdev->dev, "An equipment check has occurred"
+			" on the tape unit\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x36:
+		if (device->cdev->id.driver_info == tape_3490)
+			/* End of data. */
+			return tape_34xx_erp_failed(request, -EIO);
+		/* This erpa is reserved for 3480 */
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	case 0x37:
+		/*
+		 * Tape length error. The tape is shorter than reported in
+		 * the beginning-of-tape data.
+		 */
+		dev_warn (&device->cdev->dev, "The tape information states an"
+			" incorrect length\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x38:
+		/*
+		 * Physical end of tape. A read/write operation reached
+		 * the physical end of tape.
+		 */
+		if (request->op==TO_WRI ||
+		    request->op==TO_DSE ||
+		    request->op==TO_WTM)
+			return tape_34xx_erp_failed(request, -ENOSPC);
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x39:
+		/* Backward at Beginning of tape. */
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x3a:
+		/* Drive switched to not ready. */
+		dev_warn (&device->cdev->dev, "The tape unit is not ready\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x3b:
+		/* Manual rewind or unload. This causes an I/O error. */
+		dev_warn (&device->cdev->dev, "The tape medium has been "
+			"rewound or unloaded manually\n");
+		tape_34xx_delete_sbid_from(device, 0);
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x42:
+		/*
+		 * Degraded mode. A condition that can cause degraded
+		 * performance is detected.
+		 */
+		dev_warn (&device->cdev->dev, "The tape subsystem is running "
+			"in degraded mode\n");
+		return tape_34xx_erp_retry(request);
+	case 0x43:
+		/* Drive not ready. */
+		tape_34xx_delete_sbid_from(device, 0);
+		tape_med_state_set(device, MS_UNLOADED);
+		/* Some commands commands are successful even in this case */
+		if (sense[1] & SENSE_DRIVE_ONLINE) {
+			switch(request->op) {
+				case TO_ASSIGN:
+				case TO_UNASSIGN:
+				case TO_DIS:
+				case TO_NOP:
+					return tape_34xx_done(request);
+					break;
+				default:
+					break;
+			}
+		}
+		return tape_34xx_erp_failed(request, -ENOMEDIUM);
+	case 0x44:
+		/* Locate Block unsuccessful. */
+		if (request->op != TO_BLOCK && request->op != TO_LBL)
+			/* No locate block was issued. */
+			return tape_34xx_erp_bug(device, request,
+						 irb, sense[3]);
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x45:
+		/* The drive is assigned to a different channel path. */
+		dev_warn (&device->cdev->dev, "The tape unit is already "
+			"assigned\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x46:
+		/*
+		 * Drive not on-line. Drive may be switched offline,
+		 * the power supply may be switched off or
+		 * the drive address may not be set correctly.
+		 */
+		dev_warn (&device->cdev->dev, "The tape unit is not online\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x47:
+		/* Volume fenced. CU reports volume integrity is lost. */
+		dev_warn (&device->cdev->dev, "The control unit has fenced "
+			"access to the tape volume\n");
+		tape_34xx_delete_sbid_from(device, 0);
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x48:
+		/* Log sense data and retry request. */
+		return tape_34xx_erp_retry(request);
+	case 0x49:
+		/* Bus out check. A parity check error on the bus was found. */
+		dev_warn (&device->cdev->dev, "A parity error occurred on the "
+			"tape bus\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x4a:
+		/* Control unit erp failed. */
+		dev_warn (&device->cdev->dev, "I/O error recovery failed on "
+			"the tape control unit\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x4b:
+		/*
+		 * CU and drive incompatible. The drive requests micro-program
+		 * patches, which are not available on the CU.
+		 */
+		dev_warn (&device->cdev->dev, "The tape unit requires a "
+			"firmware update\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x4c:
+		/*
+		 * Recovered Check-One failure. Cu develops a hardware error,
+		 * but is able to recover.
+		 */
+		return tape_34xx_erp_retry(request);
+	case 0x4d:
+		if (device->cdev->id.driver_info == tape_3490)
+			/*
+			 * Resetting event received. Since the driver does
+			 * not support resetting event recovery (which has to
+			 * be handled by the I/O Layer), retry our command.
+			 */
+			return tape_34xx_erp_retry(request);
+		/* This erpa is reserved for 3480. */
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	case 0x4e:
+		if (device->cdev->id.driver_info == tape_3490) {
+			/*
+			 * Maximum block size exceeded. This indicates, that
+			 * the block to be written is larger than allowed for
+			 * buffered mode.
+			 */
+			dev_warn (&device->cdev->dev, "The maximum block size"
+				" for buffered mode is exceeded\n");
+			return tape_34xx_erp_failed(request, -ENOBUFS);
+		}
+		/* This erpa is reserved for 3480. */
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	case 0x50:
+		/*
+		 * Read buffered log (Overflow). CU is running in extended
+		 * buffered log mode, and a counter overflows. This should
+		 * never happen, since we're never running in extended
+		 * buffered log mode.
+		 */
+		return tape_34xx_erp_retry(request);
+	case 0x51:
+		/*
+		 * Read buffered log (EOV). EOF processing occurs while the
+		 * CU is in extended buffered log mode. This should never
+		 * happen, since we're never running in extended buffered
+		 * log mode.
+		 */
+		return tape_34xx_erp_retry(request);
+	case 0x52:
+		/* End of Volume complete. Rewind unload completed ok. */
+		if (request->op == TO_RUN) {
+			tape_med_state_set(device, MS_UNLOADED);
+			tape_34xx_delete_sbid_from(device, 0);
+			return tape_34xx_erp_succeeded(request);
+		}
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	case 0x53:
+		/* Global command intercept. */
+		return tape_34xx_erp_retry(request);
+	case 0x54:
+		/* Channel interface recovery (temporary). */
+		return tape_34xx_erp_retry(request);
+	case 0x55:
+		/* Channel interface recovery (permanent). */
+		dev_warn (&device->cdev->dev, "A channel interface error cannot be"
+			" recovered\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x56:
+		/* Channel protocol error. */
+		dev_warn (&device->cdev->dev, "A channel protocol error "
+			"occurred\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x57:
+		/*
+		 * 3480: Attention intercept.
+		 * 3490: Global status intercept.
+		 */
+		return tape_34xx_erp_retry(request);
+	case 0x5a:
+		/*
+		 * Tape length incompatible. The tape inserted is too long,
+		 * which could cause damage to the tape or the drive.
+		 */
+		dev_warn (&device->cdev->dev, "The tape unit does not support "
+			"the tape length\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x5b:
+		/* Format 3480 XF incompatible */
+		if (sense[1] & SENSE_BEGINNING_OF_TAPE)
+			/* The tape will get overwritten. */
+			return tape_34xx_erp_retry(request);
+		dev_warn (&device->cdev->dev, "The tape unit does not support"
+			" format 3480 XF\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x5c:
+		/* Format 3480-2 XF incompatible */
+		dev_warn (&device->cdev->dev, "The tape unit does not support tape "
+			"format 3480-2 XF\n");
+		return tape_34xx_erp_failed(request, -EIO);
+	case 0x5d:
+		/* Tape length violation. */
+		dev_warn (&device->cdev->dev, "The tape unit does not support"
+			" the current tape length\n");
+		return tape_34xx_erp_failed(request, -EMEDIUMTYPE);
+	case 0x5e:
+		/* Compaction algorithm incompatible. */
+		dev_warn (&device->cdev->dev, "The tape unit does not support"
+			" the compaction algorithm\n");
+		return tape_34xx_erp_failed(request, -EMEDIUMTYPE);
+
+		/* The following erpas should have been covered earlier. */
+	case 0x23: /* Read data check. */
+	case 0x25: /* Write data check. */
+	case 0x26: /* Data check (read opposite). */
+	case 0x28: /* Write id mark check. */
+	case 0x31: /* Tape void. */
+	case 0x40: /* Overrun error. */
+	case 0x41: /* Record sequence error. */
+		/* All other erpas are reserved for future use. */
+	default:
+		return tape_34xx_erp_bug(device, request, irb, sense[3]);
+	}
+}
+
+/*
+ * 3480/3490 interrupt handler
+ */
+static int
+tape_34xx_irq(struct tape_device *device, struct tape_request *request,
+	      struct irb *irb)
+{
+	if (request == NULL)
+		return tape_34xx_unsolicited_irq(device, irb);
+
+	if ((irb->scsw.cmd.dstat & DEV_STAT_UNIT_EXCEP) &&
+	    (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) &&
+	    (request->op == TO_WRI)) {
+		/* Write at end of volume */
+		return tape_34xx_erp_failed(request, -ENOSPC);
+	}
+
+	if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK)
+		return tape_34xx_unit_check(device, request, irb);
+
+	if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) {
+		/*
+		 * A unit exception occurs on skipping over a tapemark block.
+		 */
+		if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_EXCEP) {
+			if (request->op == TO_BSB || request->op == TO_FSB)
+				request->rescnt++;
+			else
+				DBF_EVENT(5, "Unit Exception!\n");
+		}
+		return tape_34xx_done(request);
+	}
+
+	DBF_EVENT(6, "xunknownirq\n");
+	tape_dump_sense_dbf(device, request, irb);
+	return TAPE_IO_STOP;
+}
+
+/*
+ * ioctl_overload
+ */
+static int
+tape_34xx_ioctl(struct tape_device *device, unsigned int cmd, unsigned long arg)
+{
+	if (cmd == TAPE390_DISPLAY) {
+		struct display_struct disp;
+
+		if (copy_from_user(&disp, (char __user *) arg, sizeof(disp)) != 0)
+			return -EFAULT;
+
+		return tape_std_display(device, &disp);
+	} else
+		return -EINVAL;
+}
+
+static inline void
+tape_34xx_append_new_sbid(struct tape_34xx_block_id bid, struct list_head *l)
+{
+	struct tape_34xx_sbid *	new_sbid;
+
+	new_sbid = kmalloc(sizeof(*new_sbid), GFP_ATOMIC);
+	if (!new_sbid)
+		return;
+
+	new_sbid->bid = bid;
+	list_add(&new_sbid->list, l);
+}
+
+/*
+ * Build up the search block ID list. The block ID consists of a logical
+ * block number and a hardware specific part. The hardware specific part
+ * helps the tape drive to speed up searching for a specific block.
+ */
+static void
+tape_34xx_add_sbid(struct tape_device *device, struct tape_34xx_block_id bid)
+{
+	struct list_head *	sbid_list;
+	struct tape_34xx_sbid *	sbid;
+	struct list_head *	l;
+
+	/*
+	 * immediately return if there is no list at all or the block to add
+	 * is located in segment 1 of wrap 0 because this position is used
+	 * if no hardware position data is supplied.
+	 */
+	sbid_list = (struct list_head *) device->discdata;
+	if (!sbid_list || (bid.segment < 2 && bid.wrap == 0))
+		return;
+
+	/*
+	 * Search the position where to insert the new entry. Hardware
+	 * acceleration uses only the segment and wrap number. So we
+	 * need only one entry for a specific wrap/segment combination.
+	 * If there is a block with a lower number but the same hard-
+	 * ware position data we just update the block number in the
+	 * existing entry.
+	 */
+	list_for_each(l, sbid_list) {
+		sbid = list_entry(l, struct tape_34xx_sbid, list);
+
+		if (
+			(sbid->bid.segment == bid.segment) &&
+			(sbid->bid.wrap    == bid.wrap)
+		) {
+			if (bid.block < sbid->bid.block)
+				sbid->bid = bid;
+			else return;
+			break;
+		}
+
+		/* Sort in according to logical block number. */
+		if (bid.block < sbid->bid.block) {
+			tape_34xx_append_new_sbid(bid, l->prev);
+			break;
+		}
+	}
+	/* List empty or new block bigger than last entry. */
+	if (l == sbid_list)
+		tape_34xx_append_new_sbid(bid, l->prev);
+
+	DBF_LH(4, "Current list is:\n");
+	list_for_each(l, sbid_list) {
+		sbid = list_entry(l, struct tape_34xx_sbid, list);
+		DBF_LH(4, "%d:%03d@%05d\n",
+			sbid->bid.wrap,
+			sbid->bid.segment,
+			sbid->bid.block
+		);
+	}
+}
+
+/*
+ * Delete all entries from the search block ID list that belong to tape blocks
+ * equal or higher than the given number.
+ */
+static void
+tape_34xx_delete_sbid_from(struct tape_device *device, int from)
+{
+	struct list_head *	sbid_list;
+	struct tape_34xx_sbid *	sbid;
+	struct list_head *	l;
+	struct list_head *	n;
+
+	sbid_list = (struct list_head *) device->discdata;
+	if (!sbid_list)
+		return;
+
+	list_for_each_safe(l, n, sbid_list) {
+		sbid = list_entry(l, struct tape_34xx_sbid, list);
+		if (sbid->bid.block >= from) {
+			DBF_LH(4, "Delete sbid %d:%03d@%05d\n",
+				sbid->bid.wrap,
+				sbid->bid.segment,
+				sbid->bid.block
+			);
+			list_del(l);
+			kfree(sbid);
+		}
+	}
+}
+
+/*
+ * Merge hardware position data into a block id.
+ */
+static void
+tape_34xx_merge_sbid(
+	struct tape_device *		device,
+	struct tape_34xx_block_id *	bid
+) {
+	struct tape_34xx_sbid *	sbid;
+	struct tape_34xx_sbid *	sbid_to_use;
+	struct list_head *	sbid_list;
+	struct list_head *	l;
+
+	sbid_list = (struct list_head *) device->discdata;
+	bid->wrap    = 0;
+	bid->segment = 1;
+
+	if (!sbid_list || list_empty(sbid_list))
+		return;
+
+	sbid_to_use = NULL;
+	list_for_each(l, sbid_list) {
+		sbid = list_entry(l, struct tape_34xx_sbid, list);
+
+		if (sbid->bid.block >= bid->block)
+			break;
+		sbid_to_use = sbid;
+	}
+	if (sbid_to_use) {
+		bid->wrap    = sbid_to_use->bid.wrap;
+		bid->segment = sbid_to_use->bid.segment;
+		DBF_LH(4, "Use %d:%03d@%05d for %05d\n",
+			sbid_to_use->bid.wrap,
+			sbid_to_use->bid.segment,
+			sbid_to_use->bid.block,
+			bid->block
+		);
+	}
+}
+
+static int
+tape_34xx_setup_device(struct tape_device * device)
+{
+	int			rc;
+	struct list_head *	discdata;
+
+	DBF_EVENT(6, "34xx device setup\n");
+	if ((rc = tape_std_assign(device)) == 0) {
+		if ((rc = tape_34xx_medium_sense(device)) != 0) {
+			DBF_LH(3, "34xx medium sense returned %d\n", rc);
+		}
+	}
+	discdata = kmalloc(sizeof(struct list_head), GFP_KERNEL);
+	if (discdata) {
+			INIT_LIST_HEAD(discdata);
+			device->discdata = discdata;
+	}
+
+	return rc;
+}
+
+static void
+tape_34xx_cleanup_device(struct tape_device *device)
+{
+	tape_std_unassign(device);
+	
+	if (device->discdata) {
+		tape_34xx_delete_sbid_from(device, 0);
+		kfree(device->discdata);
+		device->discdata = NULL;
+	}
+}
+
+
+/*
+ * MTTELL: Tell block. Return the number of block relative to current file.
+ */
+static int
+tape_34xx_mttell(struct tape_device *device, int mt_count)
+{
+	struct {
+		struct tape_34xx_block_id	cbid;
+		struct tape_34xx_block_id	dbid;
+	} __attribute__ ((packed)) block_id;
+	int rc;
+
+	rc = tape_std_read_block_id(device, (__u64 *) &block_id);
+	if (rc)
+		return rc;
+
+	tape_34xx_add_sbid(device, block_id.cbid);
+	return block_id.cbid.block;
+}
+
+/*
+ * MTSEEK: seek to the specified block.
+ */
+static int
+tape_34xx_mtseek(struct tape_device *device, int mt_count)
+{
+	struct tape_request *request;
+	struct tape_34xx_block_id *	bid;
+
+	if (mt_count > 0x3fffff) {
+		DBF_EXCEPTION(6, "xsee parm\n");
+		return -EINVAL;
+	}
+	request = tape_alloc_request(3, 4);
+	if (IS_ERR(request))
+		return PTR_ERR(request);
+
+	/* setup ccws */
+	request->op = TO_LBL;
+	bid         = (struct tape_34xx_block_id *) request->cpdata;
+	bid->format = (*device->modeset_byte & 0x08) ?
+			TAPE34XX_FMT_3480_XF : TAPE34XX_FMT_3480;
+	bid->block  = mt_count;
+	tape_34xx_merge_sbid(device, bid);
+
+	tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
+	tape_ccw_cc(request->cpaddr + 1, LOCATE, 4, request->cpdata);
+	tape_ccw_end(request->cpaddr + 2, NOP, 0, NULL);
+
+	/* execute it */
+	return tape_do_io_free(device, request);
+}
+
+/*
+ * List of 3480/3490 magnetic tape commands.
+ */
+static tape_mtop_fn tape_34xx_mtop[TAPE_NR_MTOPS] = {
+	[MTRESET]	 = tape_std_mtreset,
+	[MTFSF]		 = tape_std_mtfsf,
+	[MTBSF]		 = tape_std_mtbsf,
+	[MTFSR]		 = tape_std_mtfsr,
+	[MTBSR]		 = tape_std_mtbsr,
+	[MTWEOF]	 = tape_std_mtweof,
+	[MTREW]		 = tape_std_mtrew,
+	[MTOFFL]	 = tape_std_mtoffl,
+	[MTNOP]		 = tape_std_mtnop,
+	[MTRETEN]	 = tape_std_mtreten,
+	[MTBSFM]	 = tape_std_mtbsfm,
+	[MTFSFM]	 = tape_std_mtfsfm,
+	[MTEOM]		 = tape_std_mteom,
+	[MTERASE]	 = tape_std_mterase,
+	[MTRAS1]	 = NULL,
+	[MTRAS2]	 = NULL,
+	[MTRAS3]	 = NULL,
+	[MTSETBLK]	 = tape_std_mtsetblk,
+	[MTSETDENSITY]	 = NULL,
+	[MTSEEK]	 = tape_34xx_mtseek,
+	[MTTELL]	 = tape_34xx_mttell,
+	[MTSETDRVBUFFER] = NULL,
+	[MTFSS]		 = NULL,
+	[MTBSS]		 = NULL,
+	[MTWSM]		 = NULL,
+	[MTLOCK]	 = NULL,
+	[MTUNLOCK]	 = NULL,
+	[MTLOAD]	 = tape_std_mtload,
+	[MTUNLOAD]	 = tape_std_mtunload,
+	[MTCOMPRESSION]	 = tape_std_mtcompression,
+	[MTSETPART]	 = NULL,
+	[MTMKPART]	 = NULL
+};
+
+/*
+ * Tape discipline structure for 3480 and 3490.
+ */
+static struct tape_discipline tape_discipline_34xx = {
+	.owner = THIS_MODULE,
+	.setup_device = tape_34xx_setup_device,
+	.cleanup_device = tape_34xx_cleanup_device,
+	.process_eov = tape_std_process_eov,
+	.irq = tape_34xx_irq,
+	.read_block = tape_std_read_block,
+	.write_block = tape_std_write_block,
+	.ioctl_fn = tape_34xx_ioctl,
+	.mtop_array = tape_34xx_mtop
+};
+
+static struct ccw_device_id tape_34xx_ids[] = {
+	{ CCW_DEVICE_DEVTYPE(0x3480, 0, 0x3480, 0), .driver_info = tape_3480},
+	{ CCW_DEVICE_DEVTYPE(0x3490, 0, 0x3490, 0), .driver_info = tape_3490},
+	{ /* end of list */ },
+};
+
+static int
+tape_34xx_online(struct ccw_device *cdev)
+{
+	return tape_generic_online(
+		dev_get_drvdata(&cdev->dev),
+		&tape_discipline_34xx
+	);
+}
+
+static struct ccw_driver tape_34xx_driver = {
+	.driver = {
+		.name = "tape_34xx",
+		.owner = THIS_MODULE,
+	},
+	.ids = tape_34xx_ids,
+	.probe = tape_generic_probe,
+	.remove = tape_generic_remove,
+	.set_online = tape_34xx_online,
+	.set_offline = tape_generic_offline,
+	.freeze = tape_generic_pm_suspend,
+	.int_class = IRQIO_TAP,
+};
+
+static int
+tape_34xx_init (void)
+{
+	int rc;
+
+	TAPE_DBF_AREA = debug_register ( "tape_34xx", 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, "34xx init\n");
+	/* Register driver for 3480/3490 tapes. */
+	rc = ccw_driver_register(&tape_34xx_driver);
+	if (rc)
+		DBF_EVENT(3, "34xx init failed\n");
+	else
+		DBF_EVENT(3, "34xx registered\n");
+	return rc;
+}
+
+static void
+tape_34xx_exit(void)
+{
+	ccw_driver_unregister(&tape_34xx_driver);
+
+	debug_unregister(TAPE_DBF_AREA);
+}
+
+MODULE_DEVICE_TABLE(ccw, tape_34xx_ids);
+MODULE_AUTHOR("(C) 2001-2002 IBM Deutschland Entwicklung GmbH");
+MODULE_DESCRIPTION("Linux on zSeries channel attached 3480 tape device driver");
+MODULE_LICENSE("GPL");
+
+module_init(tape_34xx_init);
+module_exit(tape_34xx_exit);