st.c

Linux Kernel 2.6.9 for OMAP1710

/*
   SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   file Documentation/scsi/st.txt for more information.

   History:
   Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   Contribution and ideas from several people including (in alphabetical
   order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
   Michael Schaefer, J"org Weule, and Eric Youngdale.

   Copyright 1992 - 2004 Kai Makisara
   email [e-mail]

   Some small formal changes - aeb, 950809

   Last modified: 18-JAN-1998 Richard Gooch <[e-mail]> Devfs support
 */

static char *verstr = "20040403";

#include <linux/module.h>

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/mtio.h>
#include <linux/ioctl.h>
#include <linux/fcntl.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/moduleparam.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>
#include <asm/dma.h>
#include <asm/system.h>

/* The driver prints some debugging information on the console if DEBUG
   is defined and non-zero. */
#define DEBUG 0

#if DEBUG
/* The message level for the debug messages is currently set to KERN_NOTICE
   so that people can easily see the messages. Later when the debugging messages
   in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
#define ST_DEB_MSG  KERN_NOTICE
#define DEB(a) a
#define DEBC(a) if (debugging) { a ; }
#else
#define DEB(a)
#define DEBC(a)
#endif


#include "scsi.h"
#include <scsi/scsi_host.h>

#include <scsi/scsi_driver.h>
#include <scsi/scsi_ioctl.h>

#define ST_KILOBYTE 1024

#include "st_options.h"
#include "st.h"

static int buffer_kbs;
static int max_sg_segs;
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = TRUE;
static int try_wdio = TRUE;

static int st_dev_max;
static int st_nr_dev;

static struct class_simple *st_sysfs_class;

MODULE_AUTHOR("Kai Makisara");
MODULE_DESCRIPTION("SCSI Tape Driver");
MODULE_LICENSE("GPL");

/* Set 'perm' (4th argument) to 0 to disable module_param's definition
 * of sysfs parameters (which module_param doesn't yet support).
 * Sysfs parameters defined explicitly later.
 */
module_param_named(buffer_kbs, buffer_kbs, int, 0);
MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
module_param_named(max_sg_segs, max_sg_segs, int, 0);
MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");

/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
module_param_named(try_wdio, try_wdio, int, 0);
MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");

#ifndef MODULE
static int write_threshold_kbs;  /* retained for compatibility */
static struct st_dev_parm {
	char *name;
	int *val;
} parms[] __initdata = {
	{
		"buffer_kbs", &buffer_kbs
	},
	{       /* Retained for compatibility with 2.4 */
		"write_threshold_kbs", &write_threshold_kbs
	},
	{
		"max_sg_segs", NULL
	},
	{
		"try_direct_io", &try_direct_io
	}
};
#endif

/* Restrict the number of modes so that names for all are assigned */
#if ST_NBR_MODES > 16
#error "Maximum number of modes is 16"
#endif
/* Bit reversed order to get same names for same minors with all
   mode counts */
static char *st_formats[] = {
	"",  "r", "k", "s", "l", "t", "o", "u",
	"m", "v", "p", "x", "a", "y", "q", "z"}; 

/* The default definitions have been moved to st_options.h */

#define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)

/* The buffer size should fit into the 24 bits for length in the
   6-byte SCSI read and write commands. */
#if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
#error "Buffer size should not exceed (2 << 24 - 1) bytes!"
#endif

DEB( static int debugging = DEBUG; )

#define MAX_RETRIES 0
#define MAX_WRITE_RETRIES 0
#define MAX_READY_RETRIES 0
#define NO_TAPE  NOT_READY

#define ST_TIMEOUT (900 * HZ)
#define ST_LONG_TIMEOUT (14000 * HZ)

/* Remove mode bits and auto-rewind bit (7) */
#define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
    (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
#define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)

/* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
#define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
  (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )

/* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
   24 bits) */
#define SET_DENS_AND_BLK 0x10001

static rwlock_t st_dev_arr_lock = RW_LOCK_UNLOCKED;

static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
static int st_max_sg_segs = ST_MAX_SG;

static Scsi_Tape **scsi_tapes = NULL;

static int modes_defined;

static ST_buffer *new_tape_buffer(int, int, int);
static int enlarge_buffer(ST_buffer *, int, int);
static void normalize_buffer(ST_buffer *);
static int append_to_buffer(const char __user *, ST_buffer *, int);
static int from_buffer(ST_buffer *, char __user *, int);
static void move_buffer_data(ST_buffer *, int);
static void buf_to_sg(ST_buffer *, unsigned int);

static int st_map_user_pages(struct scatterlist *, const unsigned int, 
			     unsigned long, size_t, int, unsigned long);
static int sgl_map_user_pages(struct scatterlist *, const unsigned int, 
			      unsigned long, size_t, int);
static int sgl_unmap_user_pages(struct scatterlist *, const unsigned int, int);

static int st_probe(struct device *);
static int st_remove(struct device *);
static int st_init_command(struct scsi_cmnd *);

static void do_create_driverfs_files(void);
static void do_remove_driverfs_files(void);
static void do_create_class_files(Scsi_Tape *, int, int);

static struct scsi_driver st_template = {
	.owner			= THIS_MODULE,
	.gendrv = {
		.name		= "st",
		.probe		= st_probe,
		.remove		= st_remove,
	},
	.init_command		= st_init_command,
};

static int st_compression(Scsi_Tape *, int);

static int find_partition(Scsi_Tape *);
static int switch_partition(Scsi_Tape *);

static int st_int_ioctl(Scsi_Tape *, unsigned int, unsigned long);


#include "osst_detect.h"
#ifndef SIGS_FROM_OSST
#define SIGS_FROM_OSST \
	{"OnStream", "SC-", "", "osst"}, \
	{"OnStream", "DI-", "", "osst"}, \
	{"OnStream", "DP-", "", "osst"}, \
	{"OnStream", "USB", "", "osst"}, \
	{"OnStream", "FW-", "", "osst"}
#endif

struct st_reject_data {
	char *vendor;
	char *model;
	char *rev;
	char *driver_hint; /* Name of the correct driver, NULL if unknown */
};

static struct st_reject_data reject_list[] = {
	/* {"XXX", "Yy-", "", NULL},  example */
	SIGS_FROM_OSST,
	{NULL, }};

/* If the device signature is on the list of incompatible drives, the
   function returns a pointer to the name of the correct driver (if known) */
static char * st_incompatible(Scsi_Device* SDp)
{
	struct st_reject_data *rp;

	for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
		if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
		    !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
		    !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
			if (rp->driver_hint)
				return rp->driver_hint;
			else
				return "unknown";
		}
	return NULL;
}


static inline char *tape_name(Scsi_Tape *tape)
{
	return tape->disk->disk_name;
}

/* Convert the result to success code */
static int st_chk_result(Scsi_Tape *STp, Scsi_Request * SRpnt)
{
	int result = SRpnt->sr_result;
	unsigned char *sense = SRpnt->sr_sense_buffer, scode;
	DEB(const char *stp;)
	char *name = tape_name(STp);

	if (!result) {
		sense[0] = 0;	/* We don't have sense data if this byte is zero */
		return 0;
	}

	if ((driver_byte(result) & DRIVER_MASK) == DRIVER_SENSE)
		scode = sense[2] & 0x0f;
	else {
		sense[0] = 0;
		scode = 0;
	}

        DEB(
        if (debugging) {
                printk(ST_DEB_MSG "%s: Error: %x, cmd: %x %x %x %x %x %x Len: %d\n",
		       name, result,
		       SRpnt->sr_cmnd[0], SRpnt->sr_cmnd[1], SRpnt->sr_cmnd[2],
		       SRpnt->sr_cmnd[3], SRpnt->sr_cmnd[4], SRpnt->sr_cmnd[5],
		       SRpnt->sr_bufflen);
		if (driver_byte(result) & DRIVER_SENSE)
			print_req_sense("st", SRpnt);
	} else ) /* end DEB */
		if (!(driver_byte(result) & DRIVER_SENSE) ||
		    ((sense[0] & 0x70) == 0x70 &&
		     scode != NO_SENSE &&
		     scode != RECOVERED_ERROR &&
                     /* scode != UNIT_ATTENTION && */
		     scode != BLANK_CHECK &&
		     scode != VOLUME_OVERFLOW &&
		     SRpnt->sr_cmnd[0] != MODE_SENSE &&
		     SRpnt->sr_cmnd[0] != TEST_UNIT_READY)) {	/* Abnormal conditions for tape */
		if (driver_byte(result) & DRIVER_SENSE) {
			printk(KERN_WARNING "%s: Error with sense data: ", name);
			print_req_sense("st", SRpnt);
		} else
			printk(KERN_WARNING
			       "%s: Error %x (sugg. bt 0x%x, driver bt 0x%x, host bt 0x%x).\n",
			       name, result, suggestion(result),
                               driver_byte(result) & DRIVER_MASK, host_byte(result));
	}

	if (STp->cln_mode >= EXTENDED_SENSE_START) {
		if (STp->cln_sense_value)
			STp->cleaning_req |= ((SRpnt->sr_sense_buffer[STp->cln_mode] &
					       STp->cln_sense_mask) == STp->cln_sense_value);
		else
			STp->cleaning_req |= ((SRpnt->sr_sense_buffer[STp->cln_mode] &
					       STp->cln_sense_mask) != 0);
	}
	if (sense[12] == 0 && sense[13] == 0x17) /* ASC and ASCQ => cleaning requested */
		STp->cleaning_req = 1;

	STp->pos_unknown |= STp->device->was_reset;

	if ((sense[0] & 0x70) == 0x70 &&
	    scode == RECOVERED_ERROR
#if ST_RECOVERED_WRITE_FATAL
	    && SRpnt->sr_cmnd[0] != WRITE_6
	    && SRpnt->sr_cmnd[0] != WRITE_FILEMARKS
#endif
	    ) {
		STp->recover_count++;
		STp->recover_reg++;

                DEB(
		if (debugging) {
			if (SRpnt->sr_cmnd[0] == READ_6)
				stp = "read";
			else if (SRpnt->sr_cmnd[0] == WRITE_6)
				stp = "write";
			else
				stp = "ioctl";
			printk(ST_DEB_MSG "%s: Recovered %s error (%d).\n", name, stp,
			       STp->recover_count);
		} ) /* end DEB */

		if ((sense[2] & 0xe0) == 0)
			return 0;
	}
	return (-EIO);
}


/* Wakeup from interrupt */
static void st_sleep_done(Scsi_Cmnd * SCpnt)
{
	int remainder;
	Scsi_Tape *STp = container_of(SCpnt->request->rq_disk->private_data,
				    Scsi_Tape, driver);

	if ((STp->buffer)->writing &&
	    (SCpnt->sense_buffer[0] & 0x70) == 0x70 &&
	    (SCpnt->sense_buffer[2] & 0x40)) {
		/* EOM at write-behind, has all been written? */
		if ((SCpnt->sense_buffer[0] & 0x80) != 0)
			remainder = (SCpnt->sense_buffer[3] << 24) |
				(SCpnt->sense_buffer[4] << 16) |
				(SCpnt->sense_buffer[5] << 8) |
				SCpnt->sense_buffer[6];
		else
			remainder = 0;
		if ((SCpnt->sense_buffer[2] & 0x0f) == VOLUME_OVERFLOW ||
		    remainder > 0)
			(STp->buffer)->midlevel_result = SCpnt->result; /* Error */
		else
			(STp->buffer)->midlevel_result = INT_MAX;	/* OK */
	} else
		(STp->buffer)->midlevel_result = SCpnt->result;
	SCpnt->request->rq_status = RQ_SCSI_DONE;
	(STp->buffer)->last_SRpnt = SCpnt->sc_request;
	DEB( STp->write_pending = 0; )

	complete(SCpnt->request->waiting);
}

/* Do the scsi command. Waits until command performed if do_wait is true.
   Otherwise write_behind_check() is used to check that the command
   has finished. */
static Scsi_Request *
 st_do_scsi(Scsi_Request * SRpnt, Scsi_Tape * STp, unsigned char *cmd, int bytes,
	    int direction, int timeout, int retries, int do_wait)
{
	unsigned char *bp;

	if (SRpnt == NULL) {
		SRpnt = scsi_allocate_request(STp->device, GFP_ATOMIC);
		if (SRpnt == NULL) {
			DEBC( printk(KERN_ERR "%s: Can't get SCSI request.\n",
				     tape_name(STp)); );
			if (signal_pending(current))
				(STp->buffer)->syscall_result = (-EINTR);
			else
				(STp->buffer)->syscall_result = (-EBUSY);
			return NULL;
		}
	}

	init_completion(&STp->wait);
	SRpnt->sr_use_sg = STp->buffer->do_dio || (bytes > (STp->buffer)->frp[0].length);
	if (SRpnt->sr_use_sg) {
		if (!STp->buffer->do_dio)
			buf_to_sg(STp->buffer, bytes);
		SRpnt->sr_use_sg = (STp->buffer)->sg_segs;
		bp = (char *) &((STp->buffer)->sg[0]);
	} else
		bp = (STp->buffer)->b_data;
	SRpnt->sr_data_direction = direction;
	SRpnt->sr_cmd_len = 0;
	SRpnt->sr_request->waiting = &(STp->wait);
	SRpnt->sr_request->rq_status = RQ_SCSI_BUSY;
	SRpnt->sr_request->rq_disk = STp->disk;

	scsi_do_req(SRpnt, (void *) cmd, bp, bytes,
		    st_sleep_done, timeout, retries);

	if (do_wait) {
		wait_for_completion(SRpnt->sr_request->waiting);
		SRpnt->sr_request->waiting = NULL;
		(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
	}
	return SRpnt;
}


/* Handle the write-behind checking (downs the semaphore) */
static void write_behind_check(Scsi_Tape * STp)
{
	ST_buffer *STbuffer;
	ST_partstat *STps;

	STbuffer = STp->buffer;

        DEB(
	if (STp->write_pending)
		STp->nbr_waits++;
	else
		STp->nbr_finished++;
        ) /* end DEB */

	wait_for_completion(&(STp->wait));
	(STp->buffer)->last_SRpnt->sr_request->waiting = NULL;

	(STp->buffer)->syscall_result = st_chk_result(STp, (STp->buffer)->last_SRpnt);
	scsi_release_request((STp->buffer)->last_SRpnt);

	STbuffer->buffer_bytes -= STbuffer->writing;
	STps = &(STp->ps[STp->partition]);
	if (STps->drv_block >= 0) {
		if (STp->block_size == 0)