tape_core.c

linux-2.6.15.6

/*
 *  drivers/s390/char/tape_core.c
 *    basic function of the tape device driver
 *
 *  S390 and zSeries version
 *    Copyright (C) 2001,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Carsten Otte <[e-mail]>
 *		 Michael Holzheu <[e-mail]>
 *		 Tuan Ngo-Anh <[e-mail]>
 *		 Martin Schwidefsky <[e-mail]>
 *		 Stefan Bader <[e-mail]>
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>	     // for kernel parameters
#include <linux/kmod.h>	     // for requesting modules
#include <linux/spinlock.h>  // for locks
#include <linux/vmalloc.h>
#include <linux/list.h>

#include <asm/types.h>	     // for variable types

#define TAPE_DBF_AREA	tape_core_dbf

#include "tape.h"
#include "tape_std.h"

#define PRINTK_HEADER "TAPE_CORE: "

static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
static void tape_delayed_next_request(void * data);

/*
 * One list to contain all tape devices of all disciplines, so
 * we can assign the devices to minor numbers of the same major
 * The list is protected by the rwlock
 */
static struct list_head tape_device_list = LIST_HEAD_INIT(tape_device_list);
static DEFINE_RWLOCK(tape_device_lock);

/*
 * Pointer to debug area.
 */
debug_info_t *TAPE_DBF_AREA = NULL;
EXPORT_SYMBOL(TAPE_DBF_AREA);

/*
 * Printable strings for tape enumerations.
 */
const char *tape_state_verbose[TS_SIZE] =
{
	[TS_UNUSED]   = "UNUSED",
	[TS_IN_USE]   = "IN_USE",
	[TS_BLKUSE]   = "BLKUSE",
	[TS_INIT]     = "INIT  ",
	[TS_NOT_OPER] = "NOT_OP"
};

const char *tape_op_verbose[TO_SIZE] =
{
	[TO_BLOCK] = "BLK",	[TO_BSB] = "BSB",
	[TO_BSF] = "BSF",	[TO_DSE] = "DSE",
	[TO_FSB] = "FSB",	[TO_FSF] = "FSF",
	[TO_LBL] = "LBL",	[TO_NOP] = "NOP",
	[TO_RBA] = "RBA",	[TO_RBI] = "RBI",
	[TO_RFO] = "RFO",	[TO_REW] = "REW",
	[TO_RUN] = "RUN",	[TO_WRI] = "WRI",
	[TO_WTM] = "WTM",	[TO_MSEN] = "MSN",
	[TO_LOAD] = "LOA",	[TO_READ_CONFIG] = "RCF",
	[TO_READ_ATTMSG] = "RAT",
	[TO_DIS] = "DIS",	[TO_ASSIGN] = "ASS",
	[TO_UNASSIGN] = "UAS"
};

static inline int
busid_to_int(char *bus_id)
{
	int	dec;
	int	d;
	char *	s;

	for(s = bus_id, d = 0; *s != '\0' && *s != '.'; s++)
		d = (d * 10) + (*s - '0');
	dec = d;
	for(s++, d = 0; *s != '\0' && *s != '.'; s++)
		d = (d * 10) + (*s - '0');
	dec = (dec << 8) + d;

	for(s++; *s != '\0'; s++) {
		if (*s >= '0' && *s <= '9') {
			d = *s - '0';
		} else if (*s >= 'a' && *s <= 'f') {
			d = *s - 'a' + 10;
		} else {
			d = *s - 'A' + 10;
		}
		dec = (dec << 4) + d;
	}

	return dec;
}

/*
 * Some channel attached tape specific attributes.
 *
 * FIXME: In the future the first_minor and blocksize attribute should be
 *        replaced by a link to the cdev tree.
 */
static ssize_t
tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = (struct tape_device *) dev->driver_data;
	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
}

static
DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);

static ssize_t
tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = (struct tape_device *) dev->driver_data;
	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
}

static
DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);

static ssize_t
tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = (struct tape_device *) dev->driver_data;
	return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
		"OFFLINE" : tape_state_verbose[tdev->tape_state]);
}

static
DEVICE_ATTR(state, 0444, tape_state_show, NULL);

static ssize_t
tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;
	ssize_t rc;

	tdev = (struct tape_device *) dev->driver_data;
	if (tdev->first_minor < 0)
		return scnprintf(buf, PAGE_SIZE, "N/A\n");

	spin_lock_irq(get_ccwdev_lock(tdev->cdev));
	if (list_empty(&tdev->req_queue))
		rc = scnprintf(buf, PAGE_SIZE, "---\n");
	else {
		struct tape_request *req;

		req = list_entry(tdev->req_queue.next, struct tape_request,
			list);
		rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
	}
	spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
	return rc;
}

static
DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);

static ssize_t
tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = (struct tape_device *) dev->driver_data;

	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
}

static
DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);

static struct attribute *tape_attrs[] = {
	&dev_attr_medium_state.attr,
	&dev_attr_first_minor.attr,
	&dev_attr_state.attr,
	&dev_attr_operation.attr,
	&dev_attr_blocksize.attr,
	NULL
};

static struct attribute_group tape_attr_group = {
	.attrs = tape_attrs,
};

/*
 * Tape state functions
 */
void
tape_state_set(struct tape_device *device, enum tape_state newstate)
{
	const char *str;

	if (device->tape_state == TS_NOT_OPER) {
		DBF_EVENT(3, "ts_set err: not oper\n");
		return;
	}
	DBF_EVENT(4, "ts. dev:	%x\n", device->first_minor);
	if (device->tape_state < TO_SIZE && device->tape_state >= 0)
		str = tape_state_verbose[device->tape_state];
	else
		str = "UNKNOWN TS";
	DBF_EVENT(4, "old ts:	%s\n", str);
	if (device->tape_state < TO_SIZE && device->tape_state >=0 )
		str = tape_state_verbose[device->tape_state];
	else
		str = "UNKNOWN TS";
	DBF_EVENT(4, "%s\n", str);
	DBF_EVENT(4, "new ts:\t\n");
	if (newstate < TO_SIZE && newstate >= 0)
		str = tape_state_verbose[newstate];
	else
		str = "UNKNOWN TS";
	DBF_EVENT(4, "%s\n", str);
	device->tape_state = newstate;
	wake_up(&device->state_change_wq);
}

void
tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
{
	if (device->medium_state == newstate)
		return;
	switch(newstate){
	case MS_UNLOADED:
		device->tape_generic_status |= GMT_DR_OPEN(~0);
		PRINT_INFO("(%s): Tape is unloaded\n",
			   device->cdev->dev.bus_id);
		break;
	case MS_LOADED:
		device->tape_generic_status &= ~GMT_DR_OPEN(~0);
		PRINT_INFO("(%s): Tape has been mounted\n",
			   device->cdev->dev.bus_id);
		break;
	default:
		// print nothing
		break;
	}
	device->medium_state = newstate;
	wake_up(&device->state_change_wq);
}

/*
 * Stop running ccw. Has to be called with the device lock held.
 */
static inline int
__tape_cancel_io(struct tape_device *device, struct tape_request *request)
{
	int retries;
	int rc;

	/* Check if interrupt has already been processed */
	if (request->callback == NULL)
		return 0;

	rc = 0;
	for (retries = 0; retries < 5; retries++) {
		rc = ccw_device_clear(device->cdev, (long) request);

		switch (rc) {
			case 0:
				request->status	= TAPE_REQUEST_DONE;
				return 0;
			case -EBUSY:
				request->status	= TAPE_REQUEST_CANCEL;
				schedule_work(&device->tape_dnr);
				return 0;
			case -ENODEV:
				DBF_EXCEPTION(2, "device gone, retry\n");
				break;
			case -EIO:
				DBF_EXCEPTION(2, "I/O error, retry\n");
				break;
			default:
				BUG();
		}
	}

	return rc;
}

/*
 * Add device into the sorted list, giving it the first
 * available minor number.
 */
static int
tape_assign_minor(struct tape_device *device)
{
	struct tape_device *tmp;
	int minor;

	minor = 0;
	write_lock(&tape_device_lock);
	list_for_each_entry(tmp, &tape_device_list, node) {
		if (minor < tmp->first_minor)
			break;
		minor += TAPE_MINORS_PER_DEV;
	}
	if (minor >= 256) {
		write_unlock(&tape_device_lock);
		return -ENODEV;
	}
	device->first_minor = minor;
	list_add_tail(&device->node, &tmp->node);
	write_unlock(&tape_device_lock);
	return 0;
}

/* remove device from the list */
static void
tape_remove_minor(struct tape_device *device)
{
	write_lock(&tape_device_lock);
	list_del_init(&device->node);
	device->first_minor = -1;
	write_unlock(&tape_device_lock);
}

/*
 * Set a device online.
 *
 * This function is called by the common I/O layer to move a device from the
 * detected but offline into the online state.
 * If we return an error (RC < 0) the device remains in the offline state. This
 * can happen if the device is assigned somewhere else, for example.
 */
int
tape_generic_online(struct tape_device *device,
		   struct tape_discipline *discipline)
{
	int rc;

	DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);

	if (device->tape_state != TS_INIT) {
		DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
		return -EINVAL;
	}

	/* Let the discipline have a go at the device. */
	device->discipline = discipline;
	if (!try_module_get(discipline->owner)) {
		PRINT_ERR("Cannot get module. Module gone.\n");
		return -EINVAL;
	}

	rc = discipline->setup_device(device);
	if (rc)
		goto out;
	rc = tape_assign_minor(device);
	if (rc)
		goto out_discipline;

	rc = tapechar_setup_device(device);
	if (rc)
		goto out_minor;
	rc = tapeblock_setup_device(device);
	if (rc)
		goto out_char;

	tape_state_set(device, TS_UNUSED);

	DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);

	return 0;

out_char:
	tapechar_cleanup_device(device);
out_discipline:
	device->discipline->cleanup_device(device);
	device->discipline = NULL;
out_minor:
	tape_remove_minor(device);
out:
	module_put(discipline->owner);
	return rc;
}

static inline void
tape_cleanup_device(struct tape_device *device)
{
	tapeblock_cleanup_device(device);
	tapechar_cleanup_device(device);
	device->discipline->cleanup_device(device);
	module_put(device->discipline->owner);
	tape_remove_minor(device);
	tape_med_state_set(device, MS_UNKNOWN);
}

/*
 * Set device offline.
 *
 * Called by the common I/O layer if the drive should set offline on user
 * request. We may prevent this by returning an error.
 * Manual offline is only allowed while the drive is not in use.
 */
int
tape_generic_offline(struct tape_device *device)
{
	if (!device) {
		PRINT_ERR("tape_generic_offline: no such device\n");
		return -ENODEV;
	}

	DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
		device->cdev_id, device);

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	switch (device->tape_state) {
		case TS_INIT:
		case TS_NOT_OPER:
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			break;
		case TS_UNUSED:
			tape_state_set(device, TS_INIT);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			tape_cleanup_device(device);