drivers/block/paride/pg.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
 	pg.c    (c) 1998  Grant R. Guenther <grant@torque.net>
 			  Under the terms of the GNU General Public License.

 	The pg driver provides a simple character device interface for
 	sending ATAPI commands to a device.  With the exception of the
 	ATAPI reset operation, all operations are performed by a pair
 	of read and write operations to the appropriate /dev/pgN device.
 	A write operation delivers a command and any outbound data in
 	a single buffer.  Normally, the write will succeed unless the
 	device is offline or malfunctioning, or there is already another
 	command pending.  If the write succeeds, it should be followed
 	immediately by a read operation, to obtain any returned data and
 	status information.  A read will fail if there is no operation
 	in progress.

 	As a special case, the device can be reset with a write operation,
 	and in this case, no following read is expected, or permitted.

 	There are no ioctl() operations.  Any single operation
 	may transfer at most PG_MAX_DATA bytes.  Note that the driver must
 	copy the data through an internal buffer.  In keeping with all
 	current ATAPI devices, command packets are assumed to be exactly
 	12 bytes in length.

 	To permit future changes to this interface, the headers in the
 	read and write buffers contain a single character "magic" flag.
 	Currently this flag must be the character "P".

 	By default, the driver will autoprobe for a single parallel
 	port ATAPI device, but if their individual parameters are
 	specified, the driver can handle up to 4 devices.

 	To use this device, you must have the following device
 	special files defined:

 		/dev/pg0 c 97 0
 		/dev/pg1 c 97 1
 		/dev/pg2 c 97 2
 		/dev/pg3 c 97 3

 	(You'll need to change the 97 to something else if you use
 	the 'major' parameter to install the driver on a different
 	major number.)

 	The behaviour of the pg 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 (97) 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 "pg").

 	    verbose     This parameter controls the amount of logging
 			that is done by the driver.  Set it to 0 for
 			quiet operation, to 1 to enable progress
 			messages while the driver probes for devices,
 			or to 2 for full debug logging.  (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:

 	    pg.drive0
 	    pg.drive1
 	    pg.drive2
 	    pg.drive3

 	In addition, you can use the parameter pg.disable to disable
 	the driver entirely.

 */

 /* Changes:

 	1.01	GRG 1998.06.16	Bug fixes
 	1.02    GRG 1998.09.24  Added jumbo support

 */

 #define PG_VERSION      "1.02"
 #define PG_MAJOR	97
 #define PG_NAME		"pg"
 #define PG_UNITS	4

 #ifndef PI_PG
 #define PI_PG	4
 #endif

 /* Here are things one can override from the insmod command.
    Most are autoprobed by paride unless set here.  Verbose is 0
    by default.

 */

 static int verbose = 0;
 static int major = PG_MAJOR;
 static char *name = PG_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};
 static int pg_drive_count;

 enum {D_PRT, D_PRO, D_UNI, D_MOD, D_SLV, D_DLY};

 /* end of parameters */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/devfs_fs_kernel.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/mtio.h>
 #include <linux/pg.h>
 #include <linux/device.h>

 #include <asm/uaccess.h>

 module_param(verbose, bool, 0644);
 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 PG_SPIN_DEL     50	/* spin delay in micro-seconds  */
 #define PG_SPIN         200
 #define PG_TMO		HZ
 #define PG_RESET_TMO	10*HZ

 #define STAT_ERR        0x01
 #define STAT_INDEX      0x02
 #define STAT_ECC        0x04
 #define STAT_DRQ        0x08
 #define STAT_SEEK       0x10
 #define STAT_WRERR      0x20
 #define STAT_READY      0x40
 #define STAT_BUSY       0x80

 #define ATAPI_IDENTIFY		0x12

 static int pg_open(struct inode *inode, struct file *file);
 static int pg_release(struct inode *inode, struct file *file);
 static ssize_t pg_read(struct file *filp, char __user *buf,
 		       size_t count, loff_t * ppos);
 static ssize_t pg_write(struct file *filp, const char __user *buf,
 			size_t count, loff_t * ppos);
 static int pg_detect(void);

 #define PG_NAMELEN      8

 struct pg {
 	struct pi_adapter pia;	/* interface to paride layer */
 	struct pi_adapter *pi;
 	int busy;		/* write done, read expected */
 	int start;		/* jiffies at command start */
 	int dlen;		/* transfer size requested */
 	unsigned long timeout;	/* timeout requested */
 	int status;		/* last sense key */
 	int drive;		/* drive */
 	unsigned long access;	/* count of active opens ... */
 	int present;		/* device present ? */
 	char *bufptr;
 	char name[PG_NAMELEN];	/* pg0, pg1, ... */
 };

 static struct pg devices[PG_UNITS];

 static int pg_identify(struct pg *dev, int log);

 static char pg_scratch[512];	/* scratch block buffer */

 static struct class_simple *pg_class;

 /* kernel glue structures */

 static struct file_operations pg_fops = {
 	.owner = THIS_MODULE,
 	.read = pg_read,
 	.write = pg_write,
 	.open = pg_open,
 	.release = pg_release,
 };

 static void pg_init_units(void)
 {
 	int unit;

 	pg_drive_count = 0;
 	for (unit = 0; unit < PG_UNITS; unit++) {
 		int *parm = *drives[unit];
 		struct pg *dev = &devices[unit];
 		dev->pi = &dev->pia;
 		clear_bit(0, &dev->access);
 		dev->busy = 0;
 		dev->present = 0;
 		dev->bufptr = NULL;
 		dev->drive = parm[D_SLV];
 		snprintf(dev->name, PG_NAMELEN, "%s%c", name, 'a'+unit);
 		if (parm[D_PRT])
 			pg_drive_count++;
 	}
 }

 static inline int status_reg(struct pg *dev)
 {
 	return pi_read_regr(dev->pi, 1, 6);
 }

 static inline int read_reg(struct pg *dev, int reg)
 {
 	return pi_read_regr(dev->pi, 0, reg);
 }

 static inline void write_reg(struct pg *dev, int reg, int val)
 {
 	pi_write_regr(dev->pi, 0, reg, val);
 }

 static inline u8 DRIVE(struct pg *dev)
 {
 	return 0xa0+0x10*dev->drive;
 }

 static void pg_sleep(int cs)
 {
 	current->state = TASK_INTERRUPTIBLE;
 	schedule_timeout(cs);
 }

 static int pg_wait(struct pg *dev, int go, int stop, unsigned long tmo, char *msg)
 {
 	int j, r, e, s, p, to;

 	dev->status = 0;

 	j = 0;
 	while ((((r = status_reg(dev)) & go) || (stop && (!(r & stop))))
 	       && time_before(jiffies, tmo)) {
 		if (j++ < PG_SPIN)
 			udelay(PG_SPIN_DEL);
 		else
 			pg_sleep(1);
 	}

 	to = time_after_eq(jiffies, tmo);

 	if ((r & (STAT_ERR & stop)) || to) {
 		s = read_reg(dev, 7);
 		e = read_reg(dev, 1);
 		p = read_reg(dev, 2);
 		if (verbose > 1)
 			printk("%s: %s: stat=0x%x err=0x%x phase=%d%s\n",
 			       dev->name, msg, s, e, p, to ? " timeout" : "");
 		if (to)
 			e |= 0x100;
 		dev->status = (e >> 4) & 0xff;
 		return -1;
 	}
 	return 0;
 }

 static int pg_command(struct pg *dev, char *cmd, int dlen, unsigned long tmo)
 {
 	int k;

 	pi_connect(dev->pi);

 	write_reg(dev, 6, DRIVE(dev));

 	if (pg_wait(dev, STAT_BUSY | STAT_DRQ, 0, tmo, "before command"))
 		goto fail;

 	write_reg(dev, 4, dlen % 256);
 	write_reg(dev, 5, dlen / 256);
 	write_reg(dev, 7, 0xa0);	/* ATAPI packet command */

 	if (pg_wait(dev, STAT_BUSY, STAT_DRQ, tmo, "command DRQ"))
 		goto fail;

 	if (read_reg(dev, 2) != 1) {
 		printk("%s: command phase error\n", dev->name);
 		goto fail;
 	}

 	pi_write_block(dev->pi, cmd, 12);

 	if (verbose > 1) {
 		printk("%s: Command sent, dlen=%d packet= ", dev->name, dlen);
 		for (k = 0; k < 12; k++)
 			printk("%02x ", cmd[k] & 0xff);
 		printk("\n");
 	}
 	return 0;
 fail:
 	pi_disconnect(dev->pi);
 	return -1;
 }

 static int pg_completion(struct pg *dev, char *buf, unsigned long tmo)
 {
 	int r, d, n, p;

 	r = pg_wait(dev, STAT_BUSY, STAT_DRQ | STAT_READY | STAT_ERR,
 		    tmo, "completion");

 	dev->dlen = 0;

 	while (read_reg(dev, 7) & STAT_DRQ) {
 		d = (read_reg(dev, 4) + 256 * read_reg(dev, 5));
 		n = ((d + 3) & 0xfffc);
 		p = read_reg(dev, 2) & 3;
 		if (p == 0)
 			pi_write_block(dev->pi, buf, n);
 		if (p == 2)
 			pi_read_block(dev->pi, buf, n);
 		if (verbose > 1)
 			printk("%s: %s %d bytes\n", dev->name,
 			       p ? "Read" : "Write", n);
 		dev->dlen += (1 - p) * d;
 		buf += d;
 		r = pg_wait(dev, STAT_BUSY, STAT_DRQ | STAT_READY | STAT_ERR,
 			    tmo, "completion");
 	}

 	pi_disconnect(dev->pi);

 	return r;
 }

 static int pg_reset(struct pg *dev)
 {
 	int i, k, err;
 	int expect[5] = { 1, 1, 1, 0x14, 0xeb };
 	int got[5];

 	pi_connect(dev->pi);
 	write_reg(dev, 6, DRIVE(dev));
 	write_reg(dev, 7, 8);

 	pg_sleep(20 * HZ / 1000);

 	k = 0;
 	while ((k++ < PG_RESET_TMO) && (status_reg(dev) & STAT_BUSY))
 		pg_sleep(1);

 	for (i = 0; i < 5; i++)
 		got[i] = read_reg(dev, i + 1);

 	err = memcmp(expect, got, sizeof(got)) ? -1 : 0;

 	if (verbose) {
 		printk("%s: Reset (%d) signature = ", dev->name, k);
 		for (i = 0; i < 5; i++)
 			printk("%3x", got[i]);
 		if (err)
 			printk(" (incorrect)");
 		printk("\n");
 	}

 	pi_disconnect(dev->pi);
 	return err;
 }

 static void xs(char *buf, char *targ, int len)
 {
 	char l = '\0';
 	int k;

 	for (k = 0; k < len; k++) {
 		char c = *buf++;
 		if (c != ' ' || c != l)
 			l = *targ++ = c;
 	}
 	if (l == ' ')
 		targ--;
 	*targ = '\0';
 }

 static int pg_identify(struct pg *dev, int log)
 {
 	int 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 buf[36];

 	s = pg_command(dev, id_cmd, 36, jiffies + PG_TMO);
 	if (s)
 		return -1;
 	s = pg_completion(dev, buf, jiffies + PG_TMO);
 	if (s)
 		return -1;

 	if (log) {
 		xs(buf + 8, mf, 8);
 		xs(buf + 16, id, 16);
 		printk("%s: %s %s, %s\n", dev->name, mf, id, ms[dev->drive]);
 	}

 	return 0;
 }

 /*
  * returns  0, with id set if drive is detected
  *	   -1, if drive detection failed
  */
 static int pg_probe(struct pg *dev)
 {
 	if (dev->drive == -1) {
 		for (dev->drive = 0; dev->drive <= 1; dev->drive++)
 			if (!pg_reset(dev))
 				return pg_identify(dev, 1);
 	} else {
 		if (!pg_reset(dev))
 			return pg_identify(dev, 1);
 	}
 	return -1;
 }

 static int pg_detect(void)
 {
 	struct pg *dev = &devices[0];
 	int k, unit;

 	printk("%s: %s version %s, major %d\n", name, name, PG_VERSION, major);

 	k = 0;
 	if (pg_drive_count == 0) {
 		if (pi_init(dev->pi, 1, -1, -1, -1, -1, -1, pg_scratch,
 			    PI_PG, verbose, dev->name)) {
 			if (!pg_probe(dev)) {
 				dev->present = 1;
 				k++;
 			} else
 				pi_release(dev->pi);
 		}

 	} else
 		for (unit = 0; unit < PG_UNITS; unit++, dev++) {
 			int *parm = *drives[unit];
 			if (!parm[D_PRT])
 				continue;
 			if (pi_init(dev->pi, 0, parm[D_PRT], parm[D_MOD],
 				    parm[D_UNI], parm[D_PRO], parm[D_DLY],
 				    pg_scratch, PI_PG, verbose, dev->name)) {
 				if (!pg_probe(dev)) {
 					dev->present = 1;
 					k++;
 				} else
 					pi_release(dev->pi);
 			}
 		}

 	if (k)
 		return 0;

 	printk("%s: No ATAPI device detected\n", name);
 	return -1;
 }

 static int pg_open(struct inode *inode, struct file *file)
 {
 	int unit = iminor(inode) & 0x7f;
 	struct pg *dev = &devices[unit];

 	if ((unit >= PG_UNITS) || (!dev->present))
 		return -ENODEV;

 	if (test_and_set_bit(0, &dev->access))
 		return -EBUSY;

 	if (dev->busy) {
 		pg_reset(dev);
 		dev->busy = 0;
 	}

 	pg_identify(dev, (verbose > 1));

 	dev->bufptr = kmalloc(PG_MAX_DATA, GFP_KERNEL);
 	if (dev->bufptr == NULL) {
 		clear_bit(0, &dev->access);
 		printk("%s: buffer allocation failed\n", dev->name);
 		return -ENOMEM;
 	}

 	file->private_data = dev;

 	return 0;
 }

 static int pg_release(struct inode *inode, struct file *file)
 {
 	struct pg *dev = file->private_data;

 	kfree(dev->bufptr);
 	dev->bufptr = NULL;
 	clear_bit(0, &dev->access);

 	return 0;
 }

 static ssize_t pg_write(struct file *filp, const char __user *buf, size_t count, loff_t *ppos)
 {
 	struct pg *dev = filp->private_data;
 	struct pg_write_hdr hdr;
 	int hs = sizeof (hdr);

 	if (dev->busy)
 		return -EBUSY;
 	if (count < hs)
 		return -EINVAL;

 	if (copy_from_user(&hdr, buf, hs))
 		return -EFAULT;

 	if (hdr.magic != PG_MAGIC)
 		return -EINVAL;
 	if (hdr.dlen > PG_MAX_DATA)
 		return -EINVAL;
 	if ((count - hs) > PG_MAX_DATA)
 		return -EINVAL;

 	if (hdr.func == PG_RESET) {
 		if (count != hs)
 			return -EINVAL;
 		if (pg_reset(dev))
 			return -EIO;
 		return count;
 	}

 	if (hdr.func != PG_COMMAND)
 		return -EINVAL;

 	dev->start = jiffies;
 	dev->timeout = hdr.timeout * HZ + HZ / 2 + jiffies;

 	if (pg_command(dev, hdr.packet, hdr.dlen, jiffies + PG_TMO)) {
 		if (dev->status & 0x10)
 			return -ETIME;
 		return -EIO;
 	}

 	dev->busy = 1;

 	if (copy_from_user(dev->bufptr, buf + hs, count - hs))
 		return -EFAULT;
 	return count;
 }

 static ssize_t pg_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
 {
 	struct pg *dev = filp->private_data;
 	struct pg_read_hdr hdr;
 	int hs = sizeof (hdr);
 	int copy;

 	if (!dev->busy)
 		return -EINVAL;
 	if (count < hs)
 		return -EINVAL;

 	dev->busy = 0;

 	if (pg_completion(dev, dev->bufptr, dev->timeout))
 		if (dev->status & 0x10)
 			return -ETIME;

 	hdr.magic = PG_MAGIC;
 	hdr.dlen = dev->dlen;
 	copy = 0;

 	if (hdr.dlen < 0) {
 		hdr.dlen = -1 * hdr.dlen;
 		copy = hdr.dlen;
 		if (copy > (count - hs))
 			copy = count - hs;
 	}

 	hdr.duration = (jiffies - dev->start + HZ / 2) / HZ;
 	hdr.scsi = dev->status & 0x0f;

 	if (copy_to_user(buf, &hdr, hs))
 		return -EFAULT;
 	if (copy > 0)
 		if (copy_to_user(buf + hs, dev->bufptr, copy))
 			return -EFAULT;
 	return copy + hs;
 }

 static int __init pg_init(void)
 {
 	int unit, err = 0;

 	if (disable){
 		err = -1;
 		goto out;
 	}

 	pg_init_units();

 	if (pg_detect()) {
 		err = -1;
 		goto out;
 	}

 	if (register_chrdev(major, name, &pg_fops)) {
 		printk("pg_init: unable to get major number %d\n", major);
 		for (unit = 0; unit < PG_UNITS; unit++) {
 			struct pg *dev = &devices[unit];
 			if (dev->present)
 				pi_release(dev->pi);
 		}
 		err = -1;
 		goto out;
 	}
 	pg_class = class_simple_create(THIS_MODULE, "pg");
 	if (IS_ERR(pg_class)) {
 		err = PTR_ERR(pg_class);
 		goto out_chrdev;
 	}
 	devfs_mk_dir("pg");
 	for (unit = 0; unit < PG_UNITS; unit++) {
 		struct pg *dev = &devices[unit];
 		if (dev->present) {
 			class_simple_device_add(pg_class, MKDEV(major, unit),
 					NULL, "pg%u", unit);
 			err = devfs_mk_cdev(MKDEV(major, unit),
 				      S_IFCHR | S_IRUSR | S_IWUSR, "pg/%u",
 				      unit);
 			if (err)
 				goto out_class;
 		}
 	}
 	err = 0;
 	goto out;

 out_class:
 	class_simple_device_remove(MKDEV(major, unit));
 	class_simple_destroy(pg_class);
 out_chrdev:
 	unregister_chrdev(major, "pg");
 out:
 	return err;
 }

 static void __exit pg_exit(void)
 {
 	int unit;

 	for (unit = 0; unit < PG_UNITS; unit++) {
 		struct pg *dev = &devices[unit];
 		if (dev->present) {
 			class_simple_device_remove(MKDEV(major, unit));
 			devfs_remove("pg/%u", unit);
 		}
 	}
 	class_simple_destroy(pg_class);
 	devfs_remove("pg");
 	unregister_chrdev(major, name);

 	for (unit = 0; unit < PG_UNITS; unit++) {
 		struct pg *dev = &devices[unit];
 		if (dev->present)
 			pi_release(dev->pi);
 	}
 }

 MODULE_LICENSE("GPL");
 module_init(pg_init)
 module_exit(pg_exit)
	/*
	pg.c (c) 1998 Grant R. Guenther <grant@torque.net>
	Under the terms of the GNU General Public License.

	The pg driver provides a simple character device interface for
	sending ATAPI commands to a device. With the exception of the
	ATAPI reset operation, all operations are performed by a pair
	of read and write operations to the appropriate /dev/pgN device.
	A write operation delivers a command and any outbound data in
	a single buffer. Normally, the write will succeed unless the
	device is offline or malfunctioning, or there is already another
	command pending. If the write succeeds, it should be followed
	immediately by a read operation, to obtain any returned data and
	status information. A read will fail if there is no operation
	in progress.

	As a special case, the device can be reset with a write operation,
	and in this case, no following read is expected, or permitted.

	There are no ioctl() operations. Any single operation
	may transfer at most PG_MAX_DATA bytes. Note that the driver must
	copy the data through an internal buffer. In keeping with all
	current ATAPI devices, command packets are assumed to be exactly
	12 bytes in length.

	To permit future changes to this interface, the headers in the
	read and write buffers contain a single character "magic" flag.
	Currently this flag must be the character "P".

	By default, the driver will autoprobe for a single parallel
	port ATAPI device, but if their individual parameters are
	specified, the driver can handle up to 4 devices.

	To use this device, you must have the following device
	special files defined:

	/dev/pg0 c 97 0
	/dev/pg1 c 97 1
	/dev/pg2 c 97 2
	/dev/pg3 c 97 3

	(You'll need to change the 97 to something else if you use
	the 'major' parameter to install the driver on a different
	major number.)

	The behaviour of the pg 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 (97) 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 "pg").

	verbose This parameter controls the amount of logging
	that is done by the driver. Set it to 0 for
	quiet operation, to 1 to enable progress
	messages while the driver probes for devices,
	or to 2 for full debug logging. (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:

	pg.drive0
	pg.drive1
	pg.drive2
	pg.drive3

	In addition, you can use the parameter pg.disable to disable
	the driver entirely.

	*/

	/* Changes:

	1.01 GRG 1998.06.16 Bug fixes
	1.02 GRG 1998.09.24 Added jumbo support

	*/

	#define PG_VERSION "1.02"
	#define PG_MAJOR 97
	#define PG_NAME "pg"
	#define PG_UNITS 4

	#ifndef PI_PG
	#define PI_PG 4
	#endif

	/* Here are things one can override from the insmod command.
	Most are autoprobed by paride unless set here. Verbose is 0
	by default.

	*/

	static int verbose = 0;
	static int major = PG_MAJOR;
	static char *name = PG_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};
	static int pg_drive_count;

	enum {D_PRT, D_PRO, D_UNI, D_MOD, D_SLV, D_DLY};

	/* end of parameters */

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/fs.h>
	#include <linux/devfs_fs_kernel.h>
	#include <linux/delay.h>
	#include <linux/slab.h>
	#include <linux/mtio.h>
	#include <linux/pg.h>
	#include <linux/device.h>

	#include <asm/uaccess.h>

	module_param(verbose, bool, 0644);
	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 PG_SPIN_DEL 50 /* spin delay in micro-seconds */
	#define PG_SPIN 200
	#define PG_TMO HZ
	#define PG_RESET_TMO 10*HZ

	#define STAT_ERR 0x01
	#define STAT_INDEX 0x02
	#define STAT_ECC 0x04
	#define STAT_DRQ 0x08
	#define STAT_SEEK 0x10
	#define STAT_WRERR 0x20
	#define STAT_READY 0x40
	#define STAT_BUSY 0x80

	#define ATAPI_IDENTIFY 0x12

	static int pg_open(struct inode inode, struct file file);
	static int pg_release(struct inode inode, struct file file);
	static ssize_t pg_read(struct file filp, char __user buf,
	size_t count, loff_t * ppos);
	static ssize_t pg_write(struct file filp, const char __user buf,
	size_t count, loff_t * ppos);
	static int pg_detect(void);

	#define PG_NAMELEN 8

	struct pg {
	struct pi_adapter pia; /* interface to paride layer */
	struct pi_adapter *pi;
	int busy; /* write done, read expected */
	int start; /* jiffies at command start */
	int dlen; /* transfer size requested */
	unsigned long timeout; /* timeout requested */
	int status; /* last sense key */
	int drive; /* drive */
	unsigned long access; /* count of active opens ... */
	int present; /* device present ? */
	char *bufptr;
	char name[PG_NAMELEN]; /* pg0, pg1, ... */
	};

	static struct pg devices[PG_UNITS];

	static int pg_identify(struct pg *dev, int log);

	static char pg_scratch[512]; /* scratch block buffer */

	static struct class_simple *pg_class;

	/* kernel glue structures */

	static struct file_operations pg_fops = {
	.owner = THIS_MODULE,
	.read = pg_read,
	.write = pg_write,
	.open = pg_open,
	.release = pg_release,
	};

	static void pg_init_units(void)
	{
	int unit;

	pg_drive_count = 0;
	for (unit = 0; unit < PG_UNITS; unit++) {
	int parm = drives[unit];
	struct pg *dev = &devices[unit];
	dev->pi = &dev->pia;
	clear_bit(0, &dev->access);
	dev->busy = 0;
	dev->present = 0;
	dev->bufptr = NULL;
	dev->drive = parm[D_SLV];
	snprintf(dev->name, PG_NAMELEN, "%s%c", name, 'a'+unit);
	if (parm[D_PRT])
	pg_drive_count++;
	}
	}

	static inline int status_reg(struct pg *dev)
	{
	return pi_read_regr(dev->pi, 1, 6);
	}

	static inline int read_reg(struct pg *dev, int reg)
	{
	return pi_read_regr(dev->pi, 0, reg);
	}

	static inline void write_reg(struct pg *dev, int reg, int val)
	{
	pi_write_regr(dev->pi, 0, reg, val);
	}

	static inline u8 DRIVE(struct pg *dev)
	{
	return 0xa0+0x10*dev->drive;
	}

	static void pg_sleep(int cs)
	{
	current->state = TASK_INTERRUPTIBLE;
	schedule_timeout(cs);
	}

	static int pg_wait(struct pg dev, int go, int stop, unsigned long tmo, char msg)
	{
	int j, r, e, s, p, to;

	dev->status = 0;

	j = 0;
	while ((((r = status_reg(dev)) & go) \|\| (stop && (!(r & stop))))
	&& time_before(jiffies, tmo)) {
	if (j++ < PG_SPIN)
	udelay(PG_SPIN_DEL);
	else
	pg_sleep(1);
	}

	to = time_after_eq(jiffies, tmo);

	if ((r & (STAT_ERR & stop)) \|\| to) {
	s = read_reg(dev, 7);
	e = read_reg(dev, 1);
	p = read_reg(dev, 2);
	if (verbose > 1)
	printk("%s: %s: stat=0x%x err=0x%x phase=%d%s\n",
	dev->name, msg, s, e, p, to ? " timeout" : "");
	if (to)
	e \|= 0x100;
	dev->status = (e >> 4) & 0xff;
	return -1;
	}
	return 0;
	}

	static int pg_command(struct pg dev, char cmd, int dlen, unsigned long tmo)
	{
	int k;

	pi_connect(dev->pi);

	write_reg(dev, 6, DRIVE(dev));

	if (pg_wait(dev, STAT_BUSY \| STAT_DRQ, 0, tmo, "before command"))
	goto fail;

	write_reg(dev, 4, dlen % 256);
	write_reg(dev, 5, dlen / 256);
	write_reg(dev, 7, 0xa0); /* ATAPI packet command */

	if (pg_wait(dev, STAT_BUSY, STAT_DRQ, tmo, "command DRQ"))
	goto fail;

	if (read_reg(dev, 2) != 1) {
	printk("%s: command phase error\n", dev->name);
	goto fail;
	}

	pi_write_block(dev->pi, cmd, 12);

	if (verbose > 1) {
	printk("%s: Command sent, dlen=%d packet= ", dev->name, dlen);
	for (k = 0; k < 12; k++)
	printk("%02x ", cmd[k] & 0xff);
	printk("\n");
	}
	return 0;
	fail:
	pi_disconnect(dev->pi);
	return -1;
	}

	static int pg_completion(struct pg dev, char buf, unsigned long tmo)
	{
	int r, d, n, p;

	r = pg_wait(dev, STAT_BUSY, STAT_DRQ \| STAT_READY \| STAT_ERR,
	tmo, "completion");

	dev->dlen = 0;

	while (read_reg(dev, 7) & STAT_DRQ) {
	d = (read_reg(dev, 4) + 256 * read_reg(dev, 5));
	n = ((d + 3) & 0xfffc);
	p = read_reg(dev, 2) & 3;
	if (p == 0)
	pi_write_block(dev->pi, buf, n);
	if (p == 2)
	pi_read_block(dev->pi, buf, n);
	if (verbose > 1)
	printk("%s: %s %d bytes\n", dev->name,
	p ? "Read" : "Write", n);
	dev->dlen += (1 - p) * d;
	buf += d;
	r = pg_wait(dev, STAT_BUSY, STAT_DRQ \| STAT_READY \| STAT_ERR,
	tmo, "completion");
	}

	pi_disconnect(dev->pi);

	return r;
	}

	static int pg_reset(struct pg *dev)
	{
	int i, k, err;
	int expect[5] = { 1, 1, 1, 0x14, 0xeb };
	int got[5];

	pi_connect(dev->pi);
	write_reg(dev, 6, DRIVE(dev));
	write_reg(dev, 7, 8);

	pg_sleep(20 * HZ / 1000);

	k = 0;
	while ((k++ < PG_RESET_TMO) && (status_reg(dev) & STAT_BUSY))
	pg_sleep(1);

	for (i = 0; i < 5; i++)
	got[i] = read_reg(dev, i + 1);

	err = memcmp(expect, got, sizeof(got)) ? -1 : 0;

	if (verbose) {
	printk("%s: Reset (%d) signature = ", dev->name, k);
	for (i = 0; i < 5; i++)
	printk("%3x", got[i]);
	if (err)
	printk(" (incorrect)");
	printk("\n");
	}

	pi_disconnect(dev->pi);
	return err;
	}

	static void xs(char buf, char targ, int len)
	{
	char l = '\0';
	int k;

	for (k = 0; k < len; k++) {
	char c = *buf++;
	if (c != ' ' \|\| c != l)
	l = *targ++ = c;
	}
	if (l == ' ')
	targ--;
	*targ = '\0';
	}

	static int pg_identify(struct pg *dev, int log)
	{
	int 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 buf[36];

	s = pg_command(dev, id_cmd, 36, jiffies + PG_TMO);
	if (s)
	return -1;
	s = pg_completion(dev, buf, jiffies + PG_TMO);
	if (s)
	return -1;

	if (log) {
	xs(buf + 8, mf, 8);
	xs(buf + 16, id, 16);
	printk("%s: %s %s, %s\n", dev->name, mf, id, ms[dev->drive]);
	}

	return 0;
	}

	/*
	* returns 0, with id set if drive is detected
	* -1, if drive detection failed
	*/
	static int pg_probe(struct pg *dev)
	{
	if (dev->drive == -1) {
	for (dev->drive = 0; dev->drive <= 1; dev->drive++)
	if (!pg_reset(dev))
	return pg_identify(dev, 1);
	} else {
	if (!pg_reset(dev))
	return pg_identify(dev, 1);
	}
	return -1;
	}

	static int pg_detect(void)
	{
	struct pg *dev = &devices[0];
	int k, unit;

	printk("%s: %s version %s, major %d\n", name, name, PG_VERSION, major);

	k = 0;
	if (pg_drive_count == 0) {
	if (pi_init(dev->pi, 1, -1, -1, -1, -1, -1, pg_scratch,
	PI_PG, verbose, dev->name)) {
	if (!pg_probe(dev)) {
	dev->present = 1;
	k++;
	} else
	pi_release(dev->pi);
	}

	} else
	for (unit = 0; unit < PG_UNITS; unit++, dev++) {
	int parm = drives[unit];
	if (!parm[D_PRT])
	continue;
	if (pi_init(dev->pi, 0, parm[D_PRT], parm[D_MOD],
	parm[D_UNI], parm[D_PRO], parm[D_DLY],
	pg_scratch, PI_PG, verbose, dev->name)) {
	if (!pg_probe(dev)) {
	dev->present = 1;
	k++;
	} else
	pi_release(dev->pi);
	}
	}

	if (k)
	return 0;

	printk("%s: No ATAPI device detected\n", name);
	return -1;
	}

	static int pg_open(struct inode inode, struct file file)
	{
	int unit = iminor(inode) & 0x7f;
	struct pg *dev = &devices[unit];

	if ((unit >= PG_UNITS) \|\| (!dev->present))
	return -ENODEV;

	if (test_and_set_bit(0, &dev->access))
	return -EBUSY;

	if (dev->busy) {
	pg_reset(dev);
	dev->busy = 0;
	}

	pg_identify(dev, (verbose > 1));

	dev->bufptr = kmalloc(PG_MAX_DATA, GFP_KERNEL);
	if (dev->bufptr == NULL) {
	clear_bit(0, &dev->access);
	printk("%s: buffer allocation failed\n", dev->name);
	return -ENOMEM;
	}

	file->private_data = dev;

	return 0;
	}

	static int pg_release(struct inode inode, struct file file)
	{
	struct pg *dev = file->private_data;

	kfree(dev->bufptr);
	dev->bufptr = NULL;
	clear_bit(0, &dev->access);

	return 0;
	}

	static ssize_t pg_write(struct file filp, const char __user buf, size_t count, loff_t *ppos)
	{
	struct pg *dev = filp->private_data;
	struct pg_write_hdr hdr;
	int hs = sizeof (hdr);

	if (dev->busy)
	return -EBUSY;
	if (count < hs)
	return -EINVAL;

	if (copy_from_user(&hdr, buf, hs))
	return -EFAULT;

	if (hdr.magic != PG_MAGIC)
	return -EINVAL;
	if (hdr.dlen > PG_MAX_DATA)
	return -EINVAL;
	if ((count - hs) > PG_MAX_DATA)
	return -EINVAL;

	if (hdr.func == PG_RESET) {
	if (count != hs)
	return -EINVAL;
	if (pg_reset(dev))
	return -EIO;
	return count;
	}

	if (hdr.func != PG_COMMAND)
	return -EINVAL;

	dev->start = jiffies;
	dev->timeout = hdr.timeout * HZ + HZ / 2 + jiffies;

	if (pg_command(dev, hdr.packet, hdr.dlen, jiffies + PG_TMO)) {
	if (dev->status & 0x10)
	return -ETIME;
	return -EIO;
	}

	dev->busy = 1;

	if (copy_from_user(dev->bufptr, buf + hs, count - hs))
	return -EFAULT;
	return count;
	}

	static ssize_t pg_read(struct file filp, char __user buf, size_t count, loff_t *ppos)
	{
	struct pg *dev = filp->private_data;
	struct pg_read_hdr hdr;
	int hs = sizeof (hdr);
	int copy;

	if (!dev->busy)
	return -EINVAL;
	if (count < hs)
	return -EINVAL;

	dev->busy = 0;

	if (pg_completion(dev, dev->bufptr, dev->timeout))
	if (dev->status & 0x10)
	return -ETIME;

	hdr.magic = PG_MAGIC;
	hdr.dlen = dev->dlen;
	copy = 0;

	if (hdr.dlen < 0) {
	hdr.dlen = -1 * hdr.dlen;
	copy = hdr.dlen;
	if (copy > (count - hs))
	copy = count - hs;
	}

	hdr.duration = (jiffies - dev->start + HZ / 2) / HZ;
	hdr.scsi = dev->status & 0x0f;

	if (copy_to_user(buf, &hdr, hs))
	return -EFAULT;
	if (copy > 0)
	if (copy_to_user(buf + hs, dev->bufptr, copy))
	return -EFAULT;
	return copy + hs;
	}

	static int __init pg_init(void)
	{
	int unit, err = 0;

	if (disable){
	err = -1;
	goto out;
	}

	pg_init_units();

	if (pg_detect()) {
	err = -1;
	goto out;
	}

	if (register_chrdev(major, name, &pg_fops)) {
	printk("pg_init: unable to get major number %d\n", major);
	for (unit = 0; unit < PG_UNITS; unit++) {
	struct pg *dev = &devices[unit];
	if (dev->present)
	pi_release(dev->pi);
	}
	err = -1;
	goto out;
	}
	pg_class = class_simple_create(THIS_MODULE, "pg");
	if (IS_ERR(pg_class)) {
	err = PTR_ERR(pg_class);
	goto out_chrdev;
	}
	devfs_mk_dir("pg");
	for (unit = 0; unit < PG_UNITS; unit++) {
	struct pg *dev = &devices[unit];
	if (dev->present) {
	class_simple_device_add(pg_class, MKDEV(major, unit),
	NULL, "pg%u", unit);
	err = devfs_mk_cdev(MKDEV(major, unit),
	S_IFCHR \| S_IRUSR \| S_IWUSR, "pg/%u",
	unit);
	if (err)
	goto out_class;
	}
	}
	err = 0;
	goto out;

	out_class:
	class_simple_device_remove(MKDEV(major, unit));
	class_simple_destroy(pg_class);
	out_chrdev:
	unregister_chrdev(major, "pg");
	out:
	return err;
	}

	static void __exit pg_exit(void)
	{
	int unit;

	for (unit = 0; unit < PG_UNITS; unit++) {
	struct pg *dev = &devices[unit];
	if (dev->present) {
	class_simple_device_remove(MKDEV(major, unit));
	devfs_remove("pg/%u", unit);
	}
	}
	class_simple_destroy(pg_class);
	devfs_remove("pg");
	unregister_chrdev(major, name);

	for (unit = 0; unit < PG_UNITS; unit++) {
	struct pg *dev = &devices[unit];
	if (dev->present)
	pi_release(dev->pi);
	}
	}

	MODULE_LICENSE("GPL");
	module_init(pg_init)
	module_exit(pg_exit)