Initial import

1 files changed, 1016 insertions, 0 deletions

diff --git a/drivers/block/paride/pt.c b/drivers/block/paride/pt.c
new file mode 100644
index 000000000..2596042eb
--- /dev/null
+++ b/drivers/block/paride/pt.c
@@ -0,0 +1,1016 @@
+/* 
+        pt.c    (c) 1998  Grant R. Guenther <grant@torque.net>
+                          Under the terms of the GNU General Public License.
+
+        This is the high-level driver for parallel port ATAPI tape
+        drives based on chips supported by the paride module.
+
+	The driver implements both rewinding and non-rewinding
+	devices, filemarks, and the rewind ioctl.  It allocates
+	a small internal "bounce buffer" for each open device, but
+        otherwise expects buffering and blocking to be done at the
+        user level.  As with most block-structured tapes, short
+	writes are padded to full tape blocks, so reading back a file
+        may return more data than was actually written.
+
+        By default, the driver will autoprobe for a single parallel
+        port ATAPI tape drive, but if their individual parameters are
+        specified, the driver can handle up to 4 drives.
+
+	The rewinding devices are named /dev/pt0, /dev/pt1, ...
+	while the non-rewinding devices are /dev/npt0, /dev/npt1, etc.
+
+        The behaviour of the pt driver can be altered by setting
+        some parameters from the insmod command line.  The following
+        parameters are adjustable:
+
+            drive0      These four arguments can be arrays of       
+            drive1      1-6 integers as follows:
+            drive2
+            drive3      <prt>,<pro>,<uni>,<mod>,<slv>,<dly>
+
+                        Where,
+
+                <prt>   is the base of the parallel port address for
+                        the corresponding drive.  (required)
+
+                <pro>   is the protocol number for the adapter that
+                        supports this drive.  These numbers are
+                        logged by 'paride' when the protocol modules
+                        are initialised.  (0 if not given)
+
+                <uni>   for those adapters that support chained
+                        devices, this is the unit selector for the
+                        chain of devices on the given port.  It should
+                        be zero for devices that don't support chaining.
+                        (0 if not given)
+
+                <mod>   this can be -1 to choose the best mode, or one
+                        of the mode numbers supported by the adapter.
+                        (-1 if not given)
+
+                <slv>   ATAPI devices can be jumpered to master or slave.
+                        Set this to 0 to choose the master drive, 1 to
+                        choose the slave, -1 (the default) to choose the
+                        first drive found.
+
+                <dly>   some parallel ports require the driver to 
+                        go more slowly.  -1 sets a default value that
+                        should work with the chosen protocol.  Otherwise,
+                        set this to a small integer, the larger it is
+                        the slower the port i/o.  In some cases, setting
+                        this to zero will speed up the device. (default -1)
+
+	    major	You may use this parameter to overide the
+			default major number (96) that this driver
+			will use.  Be sure to change the device
+			name as well.
+
+	    name	This parameter is a character string that
+			contains the name the kernel will use for this
+			device (in /proc output, for instance).
+			(default "pt").
+
+            verbose     This parameter controls the amount of logging
+                        that the driver will do.  Set it to 0 for
+                        normal operation, 1 to see autoprobe progress
+                        messages, or 2 to see additional debugging
+                        output.  (default 0)
+ 
+        If this driver is built into the kernel, you can use 
+        the following command line parameters, with the same values
+        as the corresponding module parameters listed above:
+
+            pt.drive0
+            pt.drive1
+            pt.drive2
+            pt.drive3
+
+        In addition, you can use the parameter pt.disable to disable
+        the driver entirely.
+
+*/
+
+/*   Changes:
+
+	1.01	GRG 1998.05.06	Round up transfer size, fix ready_wait,
+			        loosed interpretation of ATAPI standard
+				for clearing error status.
+				Eliminate sti();
+	1.02    GRG 1998.06.16  Eliminate an Ugh.
+	1.03    GRG 1998.08.15  Adjusted PT_TMO, use HZ in loop timing,
+				extra debugging
+	1.04    GRG 1998.09.24  Repair minor coding error, added jumbo support
+	
+*/
+
+#define PT_VERSION      "1.04"
+#define PT_MAJOR	96
+#define PT_NAME		"pt"
+#define PT_UNITS	4
+
+#include <linux/types.h>
+
+/* Here are things one can override from the insmod command.
+   Most are autoprobed by paride unless set here.  Verbose is on
+   by default.
+
+*/
+
+static bool verbose = 0;
+static int major = PT_MAJOR;
+static char *name = PT_NAME;
+static int disable = 0;
+
+static int drive0[6] = { 0, 0, 0, -1, -1, -1 };
+static int drive1[6] = { 0, 0, 0, -1, -1, -1 };
+static int drive2[6] = { 0, 0, 0, -1, -1, -1 };
+static int drive3[6] = { 0, 0, 0, -1, -1, -1 };
+
+static int (*drives[4])[6] = {&drive0, &drive1, &drive2, &drive3};
+
+#define D_PRT   0
+#define D_PRO   1
+#define D_UNI   2
+#define D_MOD   3
+#define D_SLV   4
+#define D_DLY   5
+
+#define DU              (*drives[unit])
+
+/* end of parameters */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/mtio.h>
+#include <linux/device.h>
+#include <linux/sched.h>	/* current, TASK_*, schedule_timeout() */
+#include <linux/mutex.h>
+
+#include <asm/uaccess.h>
+
+module_param(verbose, bool, 0);
+module_param(major, int, 0);
+module_param(name, charp, 0);
+module_param_array(drive0, int, NULL, 0);
+module_param_array(drive1, int, NULL, 0);
+module_param_array(drive2, int, NULL, 0);
+module_param_array(drive3, int, NULL, 0);
+
+#include "paride.h"
+
+#define PT_MAX_RETRIES  5
+#define PT_TMO          3000	/* interrupt timeout in jiffies */
+#define PT_SPIN_DEL     50	/* spin delay in micro-seconds  */
+#define PT_RESET_TMO    30	/* 30 seconds */
+#define PT_READY_TMO	60	/* 60 seconds */
+#define PT_REWIND_TMO	1200	/* 20 minutes */
+
+#define PT_SPIN         ((1000000/(HZ*PT_SPIN_DEL))*PT_TMO)
+
+#define STAT_ERR        0x00001
+#define STAT_INDEX      0x00002
+#define STAT_ECC        0x00004
+#define STAT_DRQ        0x00008
+#define STAT_SEEK       0x00010
+#define STAT_WRERR      0x00020
+#define STAT_READY      0x00040
+#define STAT_BUSY       0x00080
+#define STAT_SENSE	0x1f000
+
+#define ATAPI_TEST_READY	0x00
+#define ATAPI_REWIND		0x01
+#define ATAPI_REQ_SENSE		0x03
+#define ATAPI_READ_6		0x08
+#define ATAPI_WRITE_6		0x0a
+#define ATAPI_WFM		0x10
+#define ATAPI_IDENTIFY		0x12
+#define ATAPI_MODE_SENSE	0x1a
+#define ATAPI_LOG_SENSE		0x4d
+
+static DEFINE_MUTEX(pt_mutex);
+static int pt_open(struct inode *inode, struct file *file);
+static long pt_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+static int pt_release(struct inode *inode, struct file *file);
+static ssize_t pt_read(struct file *filp, char __user *buf,
+		       size_t count, loff_t * ppos);
+static ssize_t pt_write(struct file *filp, const char __user *buf,
+			size_t count, loff_t * ppos);
+static int pt_detect(void);
+
+/* bits in tape->flags */
+
+#define PT_MEDIA	1
+#define PT_WRITE_OK	2
+#define PT_REWIND	4
+#define PT_WRITING      8
+#define PT_READING     16
+#define PT_EOF	       32
+
+#define PT_NAMELEN      8
+#define PT_BUFSIZE  16384
+
+struct pt_unit {
+	struct pi_adapter pia;	/* interface to paride layer */
+	struct pi_adapter *pi;
+	int flags;		/* various state flags */
+	int last_sense;		/* result of last request sense */
+	int drive;		/* drive */
+	atomic_t available;	/* 1 if access is available 0 otherwise */
+	int bs;			/* block size */
+	int capacity;		/* Size of tape in KB */
+	int present;		/* device present ? */
+	char *bufptr;
+	char name[PT_NAMELEN];	/* pf0, pf1, ... */
+};
+
+static int pt_identify(struct pt_unit *tape);
+
+static struct pt_unit pt[PT_UNITS];
+
+static char pt_scratch[512];	/* scratch block buffer */
+
+/* kernel glue structures */
+
+static const struct file_operations pt_fops = {
+	.owner = THIS_MODULE,
+	.read = pt_read,
+	.write = pt_write,
+	.unlocked_ioctl = pt_ioctl,
+	.open = pt_open,
+	.release = pt_release,
+	.llseek = noop_llseek,
+};
+
+/* sysfs class support */
+static struct class *pt_class;
+
+static inline int status_reg(struct pi_adapter *pi)
+{
+	return pi_read_regr(pi, 1, 6);
+}
+
+static inline int read_reg(struct pi_adapter *pi, int reg)
+{
+	return pi_read_regr(pi, 0, reg);
+}
+
+static inline void write_reg(struct pi_adapter *pi, int reg, int val)
+{
+	pi_write_regr(pi, 0, reg, val);
+}
+
+static inline u8 DRIVE(struct pt_unit *tape)
+{
+	return 0xa0+0x10*tape->drive;
+}
+
+static int pt_wait(struct pt_unit *tape, int go, int stop, char *fun, char *msg)
+{
+	int j, r, e, s, p;
+	struct pi_adapter *pi = tape->pi;
+
+	j = 0;
+	while ((((r = status_reg(pi)) & go) || (stop && (!(r & stop))))
+	       && (j++ < PT_SPIN))
+		udelay(PT_SPIN_DEL);
+
+	if ((r & (STAT_ERR & stop)) || (j > PT_SPIN)) {
+		s = read_reg(pi, 7);
+		e = read_reg(pi, 1);
+		p = read_reg(pi, 2);
+		if (j > PT_SPIN)
+			e |= 0x100;
+		if (fun)
+			printk("%s: %s %s: alt=0x%x stat=0x%x err=0x%x"
+			       " loop=%d phase=%d\n",
+			       tape->name, fun, msg, r, s, e, j, p);
+		return (e << 8) + s;
+	}
+	return 0;
+}
+
+static int pt_command(struct pt_unit *tape, char *cmd, int dlen, char *fun)
+{
+	struct pi_adapter *pi = tape->pi;
+	pi_connect(pi);
+
+	write_reg(pi, 6, DRIVE(tape));
+
+	if (pt_wait(tape, STAT_BUSY | STAT_DRQ, 0, fun, "before command")) {
+		pi_disconnect(pi);
+		return -1;
+	}
+
+	write_reg(pi, 4, dlen % 256);
+	write_reg(pi, 5, dlen / 256);
+	write_reg(pi, 7, 0xa0);	/* ATAPI packet command */
+
+	if (pt_wait(tape, STAT_BUSY, STAT_DRQ, fun, "command DRQ")) {
+		pi_disconnect(pi);
+		return -1;
+	}
+
+	if (read_reg(pi, 2) != 1) {
+		printk("%s: %s: command phase error\n", tape->name, fun);
+		pi_disconnect(pi);
+		return -1;
+	}
+
+	pi_write_block(pi, cmd, 12);
+
+	return 0;
+}
+
+static int pt_completion(struct pt_unit *tape, char *buf, char *fun)
+{
+	struct pi_adapter *pi = tape->pi;
+	int r, s, n, p;
+
+	r = pt_wait(tape, STAT_BUSY, STAT_DRQ | STAT_READY | STAT_ERR,
+		    fun, "completion");
+
+	if (read_reg(pi, 7) & STAT_DRQ) {
+		n = (((read_reg(pi, 4) + 256 * read_reg(pi, 5)) +
+		      3) & 0xfffc);
+		p = read_reg(pi, 2) & 3;
+		if (p == 0)
+			pi_write_block(pi, buf, n);
+		if (p == 2)
+			pi_read_block(pi, buf, n);
+	}
+
+	s = pt_wait(tape, STAT_BUSY, STAT_READY | STAT_ERR, fun, "data done");
+
+	pi_disconnect(pi);
+
+	return (r ? r : s);
+}
+
+static void pt_req_sense(struct pt_unit *tape, int quiet)
+{
+	char rs_cmd[12] = { ATAPI_REQ_SENSE, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 };
+	char buf[16];
+	int r;
+
+	r = pt_command(tape, rs_cmd, 16, "Request sense");
+	mdelay(1);
+	if (!r)
+		pt_completion(tape, buf, "Request sense");
+
+	tape->last_sense = -1;
+	if (!r) {
+		if (!quiet)
+			printk("%s: Sense key: %x, ASC: %x, ASQ: %x\n",
+			       tape->name, buf[2] & 0xf, buf[12], buf[13]);
+		tape->last_sense = (buf[2] & 0xf) | ((buf[12] & 0xff) << 8)
+		    | ((buf[13] & 0xff) << 16);
+	}
+}
+
+static int pt_atapi(struct pt_unit *tape, char *cmd, int dlen, char *buf, char *fun)
+{
+	int r;
+
+	r = pt_command(tape, cmd, dlen, fun);
+	mdelay(1);
+	if (!r)
+		r = pt_completion(tape, buf, fun);
+	if (r)
+		pt_req_sense(tape, !fun);
+
+	return r;
+}
+
+static void pt_sleep(int cs)
+{
+	schedule_timeout_interruptible(cs);
+}
+
+static int pt_poll_dsc(struct pt_unit *tape, int pause, int tmo, char *msg)
+{
+	struct pi_adapter *pi = tape->pi;
+	int k, e, s;
+
+	k = 0;
+	e = 0;
+	s = 0;
+	while (k < tmo) {
+		pt_sleep(pause);
+		k++;
+		pi_connect(pi);
+		write_reg(pi, 6, DRIVE(tape));
+		s = read_reg(pi, 7);
+		e = read_reg(pi, 1);
+		pi_disconnect(pi);
+		if (s & (STAT_ERR | STAT_SEEK))
+			break;
+	}
+	if ((k >= tmo) || (s & STAT_ERR)) {
+		if (k >= tmo)
+			printk("%s: %s DSC timeout\n", tape->name, msg);
+		else
+			printk("%s: %s stat=0x%x err=0x%x\n", tape->name, msg, s,
+			       e);
+		pt_req_sense(tape, 0);
+		return 0;
+	}
+	return 1;
+}
+
+static void pt_media_access_cmd(struct pt_unit *tape, int tmo, char *cmd, char *fun)
+{
+	if (pt_command(tape, cmd, 0, fun)) {
+		pt_req_sense(tape, 0);
+		return;
+	}
+	pi_disconnect(tape->pi);
+	pt_poll_dsc(tape, HZ, tmo, fun);
+}
+
+static void pt_rewind(struct pt_unit *tape)
+{
+	char rw_cmd[12] = { ATAPI_REWIND, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+
+	pt_media_access_cmd(tape, PT_REWIND_TMO, rw_cmd, "rewind");
+}
+
+static void pt_write_fm(struct pt_unit *tape)
+{
+	char wm_cmd[12] = { ATAPI_WFM, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 };
+
+	pt_media_access_cmd(tape, PT_TMO, wm_cmd, "write filemark");
+}
+
+#define DBMSG(msg)      ((verbose>1)?(msg):NULL)
+
+static int pt_reset(struct pt_unit *tape)
+{
+	struct pi_adapter *pi = tape->pi;
+	int i, k, flg;
+	int expect[5] = { 1, 1, 1, 0x14, 0xeb };
+
+	pi_connect(pi);
+	write_reg(pi, 6, DRIVE(tape));
+	write_reg(pi, 7, 8);
+
+	pt_sleep(20 * HZ / 1000);
+
+	k = 0;
+	while ((k++ < PT_RESET_TMO) && (status_reg(pi) & STAT_BUSY))
+		pt_sleep(HZ / 10);
+
+	flg = 1;
+	for (i = 0; i < 5; i++)
+		flg &= (read_reg(pi, i + 1) == expect[i]);
+
+	if (verbose) {
+		printk("%s: Reset (%d) signature = ", tape->name, k);
+		for (i = 0; i < 5; i++)
+			printk("%3x", read_reg(pi, i + 1));
+		if (!flg)
+			printk(" (incorrect)");
+		printk("\n");
+	}
+
+	pi_disconnect(pi);
+	return flg - 1;
+}
+
+static int pt_ready_wait(struct pt_unit *tape, int tmo)
+{
+	char tr_cmd[12] = { ATAPI_TEST_READY, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+	int k, p;
+
+	k = 0;
+	while (k < tmo) {
+		tape->last_sense = 0;
+		pt_atapi(tape, tr_cmd, 0, NULL, DBMSG("test unit ready"));
+		p = tape->last_sense;
+		if (!p)
+			return 0;
+		if (!(((p & 0xffff) == 0x0402) || ((p & 0xff) == 6)))
+			return p;
+		k++;
+		pt_sleep(HZ);
+	}
+	return 0x000020;	/* timeout */
+}
+
+static void xs(char *buf, char *targ, int offs, int len)
+{
+	int j, k, l;
+
+	j = 0;
+	l = 0;
+	for (k = 0; k < len; k++)
+		if ((buf[k + offs] != 0x20) || (buf[k + offs] != l))
+			l = targ[j++] = buf[k + offs];
+	if (l == 0x20)
+		j--;
+	targ[j] = 0;
+}
+
+static int xn(char *buf, int offs, int size)
+{
+	int v, k;
+
+	v = 0;
+	for (k = 0; k < size; k++)
+		v = v * 256 + (buf[k + offs] & 0xff);
+	return v;
+}
+
+static int pt_identify(struct pt_unit *tape)
+{
+	int dt, s;
+	char *ms[2] = { "master", "slave" };
+	char mf[10], id[18];
+	char id_cmd[12] = { ATAPI_IDENTIFY, 0, 0, 0, 36, 0, 0, 0, 0, 0, 0, 0 };
+	char ms_cmd[12] =
+	    { ATAPI_MODE_SENSE, 0, 0x2a, 0, 36, 0, 0, 0, 0, 0, 0, 0 };
+	char ls_cmd[12] =
+	    { ATAPI_LOG_SENSE, 0, 0x71, 0, 0, 0, 0, 0, 36, 0, 0, 0 };
+	char buf[36];
+
+	s = pt_atapi(tape, id_cmd, 36, buf, "identify");
+	if (s)
+		return -1;
+
+	dt = buf[0] & 0x1f;
+	if (dt != 1) {
+		if (verbose)
+			printk("%s: Drive %d, unsupported type %d\n",
+			       tape->name, tape->drive, dt);
+		return -1;
+	}
+
+	xs(buf, mf, 8, 8);
+	xs(buf, id, 16, 16);
+
+	tape->flags = 0;
+	tape->capacity = 0;
+	tape->bs = 0;
+
+	if (!pt_ready_wait(tape, PT_READY_TMO))
+		tape->flags |= PT_MEDIA;
+
+	if (!pt_atapi(tape, ms_cmd, 36, buf, "mode sense")) {
+		if (!(buf[2] & 0x80))
+			tape->flags |= PT_WRITE_OK;
+		tape->bs = xn(buf, 10, 2);
+	}
+
+	if (!pt_atapi(tape, ls_cmd, 36, buf, "log sense"))
+		tape->capacity = xn(buf, 24, 4);
+
+	printk("%s: %s %s, %s", tape->name, mf, id, ms[tape->drive]);
+	if (!(tape->flags & PT_MEDIA))
+		printk(", no media\n");
+	else {
+		if (!(tape->flags & PT_WRITE_OK))
+			printk(", RO");
+		printk(", blocksize %d, %d MB\n", tape->bs, tape->capacity / 1024);
+	}
+
+	return 0;
+}
+
+
+/*
+ * returns  0, with id set if drive is detected
+ *	   -1, if drive detection failed
+ */
+static int pt_probe(struct pt_unit *tape)
+{
+	if (tape->drive == -1) {
+		for (tape->drive = 0; tape->drive <= 1; tape->drive++)
+			if (!pt_reset(tape))
+				return pt_identify(tape);
+	} else {
+		if (!pt_reset(tape))
+			return pt_identify(tape);
+	}
+	return -1;
+}
+
+static int pt_detect(void)
+{
+	struct pt_unit *tape;
+	int specified = 0, found = 0;
+	int unit;
+
+	printk("%s: %s version %s, major %d\n", name, name, PT_VERSION, major);
+
+	specified = 0;
+	for (unit = 0; unit < PT_UNITS; unit++) {
+		struct pt_unit *tape = &pt[unit];
+		tape->pi = &tape->pia;
+		atomic_set(&tape->available, 1);
+		tape->flags = 0;
+		tape->last_sense = 0;
+		tape->present = 0;
+		tape->bufptr = NULL;
+		tape->drive = DU[D_SLV];
+		snprintf(tape->name, PT_NAMELEN, "%s%d", name, unit);
+		if (!DU[D_PRT])
+			continue;
+		specified++;
+		if (pi_init(tape->pi, 0, DU[D_PRT], DU[D_MOD], DU[D_UNI],
+		     DU[D_PRO], DU[D_DLY], pt_scratch, PI_PT,
+		     verbose, tape->name)) {
+			if (!pt_probe(tape)) {
+				tape->present = 1;
+				found++;
+			} else
+				pi_release(tape->pi);
+		}
+	}
+	if (specified == 0) {
+		tape = pt;
+		if (pi_init(tape->pi, 1, -1, -1, -1, -1, -1, pt_scratch,
+			    PI_PT, verbose, tape->name)) {
+			if (!pt_probe(tape)) {
+				tape->present = 1;
+				found++;
+			} else
+				pi_release(tape->pi);
+		}
+
+	}
+	if (found)
+		return 0;
+
+	printk("%s: No ATAPI tape drive detected\n", name);
+	return -1;
+}
+
+static int pt_open(struct inode *inode, struct file *file)
+{
+	int unit = iminor(inode) & 0x7F;
+	struct pt_unit *tape = pt + unit;
+	int err;
+
+	mutex_lock(&pt_mutex);
+	if (unit >= PT_UNITS || (!tape->present)) {
+		mutex_unlock(&pt_mutex);
+		return -ENODEV;
+	}
+
+	err = -EBUSY;
+	if (!atomic_dec_and_test(&tape->available))
+		goto out;
+
+	pt_identify(tape);
+
+	err = -ENODEV;
+	if (!(tape->flags & PT_MEDIA))
+		goto out;
+
+	err = -EROFS;
+	if ((!(tape->flags & PT_WRITE_OK)) && (file->f_mode & FMODE_WRITE))
+		goto out;
+
+	if (!(iminor(inode) & 128))
+		tape->flags |= PT_REWIND;
+
+	err = -ENOMEM;
+	tape->bufptr = kmalloc(PT_BUFSIZE, GFP_KERNEL);
+	if (tape->bufptr == NULL) {
+		printk("%s: buffer allocation failed\n", tape->name);
+		goto out;
+	}
+
+	file->private_data = tape;
+	mutex_unlock(&pt_mutex);
+	return 0;
+
+out:
+	atomic_inc(&tape->available);
+	mutex_unlock(&pt_mutex);
+	return err;
+}
+
+static long pt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct pt_unit *tape = file->private_data;
+	struct mtop __user *p = (void __user *)arg;
+	struct mtop mtop;
+
+	switch (cmd) {
+	case MTIOCTOP:
+		if (copy_from_user(&mtop, p, sizeof(struct mtop)))
+			return -EFAULT;
+
+		switch (mtop.mt_op) {
+
+		case MTREW:
+			mutex_lock(&pt_mutex);
+			pt_rewind(tape);
+			mutex_unlock(&pt_mutex);
+			return 0;
+
+		case MTWEOF:
+			mutex_lock(&pt_mutex);
+			pt_write_fm(tape);
+			mutex_unlock(&pt_mutex);
+			return 0;
+
+		default:
+			/* FIXME: rate limit ?? */
+			printk(KERN_DEBUG "%s: Unimplemented mt_op %d\n", tape->name,
+			       mtop.mt_op);
+			return -EINVAL;
+		}
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+static int
+pt_release(struct inode *inode, struct file *file)
+{
+	struct pt_unit *tape = file->private_data;
+
+	if (atomic_read(&tape->available) > 1)
+		return -EINVAL;
+
+	if (tape->flags & PT_WRITING)
+		pt_write_fm(tape);
+
+	if (tape->flags & PT_REWIND)
+		pt_rewind(tape);
+
+	kfree(tape->bufptr);
+	tape->bufptr = NULL;
+
+	atomic_inc(&tape->available);
+
+	return 0;
+
+}
+
+static ssize_t pt_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
+{
+	struct pt_unit *tape = filp->private_data;
+	struct pi_adapter *pi = tape->pi;
+	char rd_cmd[12] = { ATAPI_READ_6, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+	int k, n, r, p, s, t, b;
+
+	if (!(tape->flags & (PT_READING | PT_WRITING))) {
+		tape->flags |= PT_READING;
+		if (pt_atapi(tape, rd_cmd, 0, NULL, "start read-ahead"))
+			return -EIO;
+	} else if (tape->flags & PT_WRITING)
+		return -EIO;
+
+	if (tape->flags & PT_EOF)
+		return 0;
+
+	t = 0;
+
+	while (count > 0) {
+
+		if (!pt_poll_dsc(tape, HZ / 100, PT_TMO, "read"))
+			return -EIO;
+
+		n = count;
+		if (n > 32768)
+			n = 32768;	/* max per command */
+		b = (n - 1 + tape->bs) / tape->bs;
+		n = b * tape->bs;	/* rounded up to even block */
+
+		rd_cmd[4] = b;
+
+		r = pt_command(tape, rd_cmd, n, "read");
+
+		mdelay(1);
+
+		if (r) {
+			pt_req_sense(tape, 0);
+			return -EIO;
+		}
+
+		while (1) {
+
+			r = pt_wait(tape, STAT_BUSY,
+				    STAT_DRQ | STAT_ERR | STAT_READY,
+				    DBMSG("read DRQ"), "");
+
+			if (r & STAT_SENSE) {
+				pi_disconnect(pi);
+				pt_req_sense(tape, 0);
+				return -EIO;
+			}
+
+			if (r)
+				tape->flags |= PT_EOF;
+
+			s = read_reg(pi, 7);
+
+			if (!(s & STAT_DRQ))
+				break;
+
+			n = (read_reg(pi, 4) + 256 * read_reg(pi, 5));
+			p = (read_reg(pi, 2) & 3);
+			if (p != 2) {
+				pi_disconnect(pi);
+				printk("%s: Phase error on read: %d\n", tape->name,
+				       p);
+				return -EIO;
+			}
+
+			while (n > 0) {
+				k = n;
+				if (k > PT_BUFSIZE)
+					k = PT_BUFSIZE;
+				pi_read_block(pi, tape->bufptr, k);
+				n -= k;
+				b = k;
+				if (b > count)
+					b = count;
+				if (copy_to_user(buf + t, tape->bufptr, b)) {
+					pi_disconnect(pi);
+					return -EFAULT;
+				}
+				t += b;
+				count -= b;
+			}
+
+		}
+		pi_disconnect(pi);
+		if (tape->flags & PT_EOF)
+			break;
+	}
+
+	return t;
+
+}
+
+static ssize_t pt_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
+{
+	struct pt_unit *tape = filp->private_data;
+	struct pi_adapter *pi = tape->pi;
+	char wr_cmd[12] = { ATAPI_WRITE_6, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+	int k, n, r, p, s, t, b;
+
+	if (!(tape->flags & PT_WRITE_OK))
+		return -EROFS;
+
+	if (!(tape->flags & (PT_READING | PT_WRITING))) {
+		tape->flags |= PT_WRITING;
+		if (pt_atapi
+		    (tape, wr_cmd, 0, NULL, "start buffer-available mode"))
+			return -EIO;
+	} else if (tape->flags & PT_READING)
+		return -EIO;
+
+	if (tape->flags & PT_EOF)
+		return -ENOSPC;
+
+	t = 0;
+
+	while (count > 0) {
+
+		if (!pt_poll_dsc(tape, HZ / 100, PT_TMO, "write"))
+			return -EIO;
+
+		n = count;
+		if (n > 32768)
+			n = 32768;	/* max per command */
+		b = (n - 1 + tape->bs) / tape->bs;
+		n = b * tape->bs;	/* rounded up to even block */
+
+		wr_cmd[4] = b;
+
+		r = pt_command(tape, wr_cmd, n, "write");
+
+		mdelay(1);
+
+		if (r) {	/* error delivering command only */
+			pt_req_sense(tape, 0);
+			return -EIO;
+		}
+
+		while (1) {
+
+			r = pt_wait(tape, STAT_BUSY,
+				    STAT_DRQ | STAT_ERR | STAT_READY,
+				    DBMSG("write DRQ"), NULL);
+
+			if (r & STAT_SENSE) {
+				pi_disconnect(pi);
+				pt_req_sense(tape, 0);
+				return -EIO;
+			}
+
+			if (r)
+				tape->flags |= PT_EOF;
+
+			s = read_reg(pi, 7);
+
+			if (!(s & STAT_DRQ))
+				break;
+
+			n = (read_reg(pi, 4) + 256 * read_reg(pi, 5));
+			p = (read_reg(pi, 2) & 3);
+			if (p != 0) {
+				pi_disconnect(pi);
+				printk("%s: Phase error on write: %d \n",
+				       tape->name, p);
+				return -EIO;
+			}
+
+			while (n > 0) {
+				k = n;
+				if (k > PT_BUFSIZE)
+					k = PT_BUFSIZE;
+				b = k;
+				if (b > count)
+					b = count;
+				if (copy_from_user(tape->bufptr, buf + t, b)) {
+					pi_disconnect(pi);
+					return -EFAULT;
+				}
+				pi_write_block(pi, tape->bufptr, k);
+				t += b;
+				count -= b;
+				n -= k;
+			}
+
+		}
+		pi_disconnect(pi);
+		if (tape->flags & PT_EOF)
+			break;
+	}
+
+	return t;
+}
+
+static int __init pt_init(void)
+{
+	int unit;
+	int err;
+
+	if (disable) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	if (pt_detect()) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	err = register_chrdev(major, name, &pt_fops);
+	if (err < 0) {
+		printk("pt_init: unable to get major number %d\n", major);
+		for (unit = 0; unit < PT_UNITS; unit++)
+			if (pt[unit].present)
+				pi_release(pt[unit].pi);
+		goto out;
+	}
+	major = err;
+	pt_class = class_create(THIS_MODULE, "pt");
+	if (IS_ERR(pt_class)) {
+		err = PTR_ERR(pt_class);
+		goto out_chrdev;
+	}
+
+	for (unit = 0; unit < PT_UNITS; unit++)
+		if (pt[unit].present) {
+			device_create(pt_class, NULL, MKDEV(major, unit), NULL,
+				      "pt%d", unit);
+			device_create(pt_class, NULL, MKDEV(major, unit + 128),
+				      NULL, "pt%dn", unit);
+		}
+	goto out;
+
+out_chrdev:
+	unregister_chrdev(major, "pt");
+out:
+	return err;
+}
+
+static void __exit pt_exit(void)
+{
+	int unit;
+	for (unit = 0; unit < PT_UNITS; unit++)
+		if (pt[unit].present) {
+			device_destroy(pt_class, MKDEV(major, unit));
+			device_destroy(pt_class, MKDEV(major, unit + 128));
+		}
+	class_destroy(pt_class);
+	unregister_chrdev(major, name);
+	for (unit = 0; unit < PT_UNITS; unit++)
+		if (pt[unit].present)
+			pi_release(pt[unit].pi);
+}
+
+MODULE_LICENSE("GPL");
+module_init(pt_init)
+module_exit(pt_exit)