// SPDX-License-Identifier: GPL-2.0-or-later

  /* 
   *  Parallel SCSI (SPI) transport specific attributes exported to sysfs.
   *
   *  Copyright (c) 2003 Silicon Graphics, Inc.  All rights reserved.
   *  Copyright (c) 2004, 2005 James Bottomley <James.Bottomley@SteelEye.com>

   */
  #include <linux/ctype.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/workqueue.h>

  #include <linux/blkdev.h>

  #include <linux/mutex.h>

  #include <linux/sysfs.h>

  #include <linux/slab.h>

  #include <linux/suspend.h>

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

  #include <scsi/scsi_cmnd.h>

  #include <scsi/scsi_eh.h>

  #include <scsi/scsi_tcq.h>

  #include <scsi/scsi_transport.h>
  #include <scsi/scsi_transport_spi.h>

  #define SPI_NUM_ATTRS 14	/* increase this if you add attributes */

  #define SPI_OTHER_ATTRS 1	/* Increase this if you add "always
  				 * on" attributes */
  #define SPI_HOST_ATTRS	1
  
  #define SPI_MAX_ECHO_BUFFER_SIZE	4096

  #define DV_LOOPS	3
  #define DV_TIMEOUT	(10*HZ)
  #define DV_RETRIES	3	/* should only need at most 
  				 * two cc/ua clears */

  /* Our blacklist flags */
  enum {

  	SPI_BLIST_NOIUS = (__force blist_flags_t)0x1,

  };
  
  /* blacklist table, modelled on scsi_devinfo.c */
  static struct {
  	char *vendor;
  	char *model;

  	blist_flags_t flags;

  } spi_static_device_list[] __initdata = {
  	{"HP", "Ultrium 3-SCSI", SPI_BLIST_NOIUS },
  	{"IBM", "ULTRIUM-TD3", SPI_BLIST_NOIUS },
  	{NULL, NULL, 0}
  };

  /* Private data accessors (keep these out of the header file) */

  #define spi_dv_in_progress(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_in_progress)

  #define spi_dv_mutex(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_mutex)

  
  struct spi_internal {
  	struct scsi_transport_template t;
  	struct spi_function_template *f;

  };
  
  #define to_spi_internal(tmpl)	container_of(tmpl, struct spi_internal, t)
  
  static const int ppr_to_ps[] = {
  	/* The PPR values 0-6 are reserved, fill them in when
  	 * the committee defines them */
  	-1,			/* 0x00 */
  	-1,			/* 0x01 */
  	-1,			/* 0x02 */
  	-1,			/* 0x03 */
  	-1,			/* 0x04 */
  	-1,			/* 0x05 */
  	-1,			/* 0x06 */
  	 3125,			/* 0x07 */
  	 6250,			/* 0x08 */
  	12500,			/* 0x09 */
  	25000,			/* 0x0a */
  	30300,			/* 0x0b */
  	50000,			/* 0x0c */
  };
  /* The PPR values at which you calculate the period in ns by multiplying
   * by 4 */
  #define SPI_STATIC_PPR	0x0c
  
  static int sprint_frac(char *dest, int value, int denom)
  {
  	int frac = value % denom;
  	int result = sprintf(dest, "%d", value / denom);
  
  	if (frac == 0)
  		return result;
  	dest[result++] = '.';
  
  	do {
  		denom /= 10;
  		sprintf(dest + result, "%d", frac / denom);
  		result++;
  		frac %= denom;
  	} while (frac);
  
  	dest[result++] = '\0';
  	return result;
  }

  static int spi_execute(struct scsi_device *sdev, const void *cmd,
  		       enum dma_data_direction dir,
  		       void *buffer, unsigned bufflen,
  		       struct scsi_sense_hdr *sshdr)

  {

  	int i, result;
  	unsigned char sense[SCSI_SENSE_BUFFERSIZE];

  	struct scsi_sense_hdr sshdr_tmp;
  
  	if (!sshdr)
  		sshdr = &sshdr_tmp;

  
  	for(i = 0; i < DV_RETRIES; i++) {

  		result = scsi_execute(sdev, cmd, dir, buffer, bufflen, sense,
  				      sshdr, DV_TIMEOUT, /* retries */ 1,

  				      REQ_FAILFAST_DEV |
  				      REQ_FAILFAST_TRANSPORT |

  				      REQ_FAILFAST_DRIVER,

  				      0, NULL);

  		if (driver_byte(result) != DRIVER_SENSE ||

  		    sshdr->sense_key != UNIT_ATTENTION)
  			break;

  	}

  	return result;

  }

  static struct {
  	enum spi_signal_type	value;
  	char			*name;
  } signal_types[] = {
  	{ SPI_SIGNAL_UNKNOWN, "unknown" },
  	{ SPI_SIGNAL_SE, "SE" },
  	{ SPI_SIGNAL_LVD, "LVD" },
  	{ SPI_SIGNAL_HVD, "HVD" },
  };
  
  static inline const char *spi_signal_to_string(enum spi_signal_type type)
  {
  	int i;

  	for (i = 0; i < ARRAY_SIZE(signal_types); i++) {

  		if (type == signal_types[i].value)
  			return signal_types[i].name;
  	}
  	return NULL;
  }
  static inline enum spi_signal_type spi_signal_to_value(const char *name)
  {
  	int i, len;

  	for (i = 0; i < ARRAY_SIZE(signal_types); i++) {

  		len =  strlen(signal_types[i].name);
  		if (strncmp(name, signal_types[i].name, len) == 0 &&
  		    (name[len] == '
  ' || name[len] == '\0'))
  			return signal_types[i].value;
  	}
  	return SPI_SIGNAL_UNKNOWN;
  }

  static int spi_host_setup(struct transport_container *tc, struct device *dev,

  			  struct device *cdev)

  {
  	struct Scsi_Host *shost = dev_to_shost(dev);
  
  	spi_signalling(shost) = SPI_SIGNAL_UNKNOWN;
  
  	return 0;
  }

  static int spi_host_configure(struct transport_container *tc,
  			      struct device *dev,

  			      struct device *cdev);

  static DECLARE_TRANSPORT_CLASS(spi_host_class,
  			       "spi_host",
  			       spi_host_setup,
  			       NULL,

  			       spi_host_configure);

  
  static int spi_host_match(struct attribute_container *cont,
  			  struct device *dev)
  {
  	struct Scsi_Host *shost;

  
  	if (!scsi_is_host_device(dev))
  		return 0;
  
  	shost = dev_to_shost(dev);
  	if (!shost->transportt  || shost->transportt->host_attrs.ac.class
  	    != &spi_host_class.class)
  		return 0;

  	return &shost->transportt->host_attrs.ac == cont;

  }

  static int spi_target_configure(struct transport_container *tc,
  				struct device *dev,

  				struct device *cdev);

  static int spi_device_configure(struct transport_container *tc,
  				struct device *dev,

  				struct device *cdev)

  {
  	struct scsi_device *sdev = to_scsi_device(dev);
  	struct scsi_target *starget = sdev->sdev_target;

  	blist_flags_t bflags;
  
  	bflags = scsi_get_device_flags_keyed(sdev, &sdev->inquiry[8],
  					     &sdev->inquiry[16],
  					     SCSI_DEVINFO_SPI);

  
  	/* Populate the target capability fields with the values
  	 * gleaned from the device inquiry */
  
  	spi_support_sync(starget) = scsi_device_sync(sdev);
  	spi_support_wide(starget) = scsi_device_wide(sdev);
  	spi_support_dt(starget) = scsi_device_dt(sdev);
  	spi_support_dt_only(starget) = scsi_device_dt_only(sdev);
  	spi_support_ius(starget) = scsi_device_ius(sdev);

  	if (bflags & SPI_BLIST_NOIUS) {
  		dev_info(dev, "Information Units disabled by blacklist
  ");
  		spi_support_ius(starget) = 0;
  	}

  	spi_support_qas(starget) = scsi_device_qas(sdev);
  
  	return 0;
  }

  static int spi_setup_transport_attrs(struct transport_container *tc,
  				     struct device *dev,

  				     struct device *cdev)

  {
  	struct scsi_target *starget = to_scsi_target(dev);
  
  	spi_period(starget) = -1;	/* illegal value */

  	spi_min_period(starget) = 0;

  	spi_offset(starget) = 0;	/* async */

  	spi_max_offset(starget) = 255;

  	spi_width(starget) = 0;	/* narrow */

  	spi_max_width(starget) = 1;

  	spi_iu(starget) = 0;	/* no IU */

  	spi_max_iu(starget) = 1;

  	spi_dt(starget) = 0;	/* ST */
  	spi_qas(starget) = 0;

  	spi_max_qas(starget) = 1;

  	spi_wr_flow(starget) = 0;
  	spi_rd_strm(starget) = 0;
  	spi_rti(starget) = 0;
  	spi_pcomp_en(starget) = 0;

  	spi_hold_mcs(starget) = 0;

  	spi_dv_pending(starget) = 0;

  	spi_dv_in_progress(starget) = 0;

  	spi_initial_dv(starget) = 0;

  	mutex_init(&spi_dv_mutex(starget));

  
  	return 0;
  }

  #define spi_transport_show_simple(field, format_string)			\
  									\
  static ssize_t								\

  show_spi_transport_##field(struct device *dev, 			\
  			   struct device_attribute *attr, char *buf)	\

  {									\

  	struct scsi_target *starget = transport_class_to_starget(dev);	\

  	struct spi_transport_attrs *tp;					\
  									\
  	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
  	return snprintf(buf, 20, format_string, tp->field);		\
  }
  
  #define spi_transport_store_simple(field, format_string)		\
  									\
  static ssize_t								\

  store_spi_transport_##field(struct device *dev, 			\
  			    struct device_attribute *attr, 		\
  			    const char *buf, size_t count)		\

  {									\
  	int val;							\

  	struct scsi_target *starget = transport_class_to_starget(dev);	\

  	struct spi_transport_attrs *tp;					\
  									\
  	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
  	val = simple_strtoul(buf, NULL, 0);				\
  	tp->field = val;						\
  	return count;							\
  }

  #define spi_transport_show_function(field, format_string)		\
  									\
  static ssize_t								\

  show_spi_transport_##field(struct device *dev, 			\
  			   struct device_attribute *attr, char *buf)	\

  {									\

  	struct scsi_target *starget = transport_class_to_starget(dev);	\

  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
  	struct spi_transport_attrs *tp;					\
  	struct spi_internal *i = to_spi_internal(shost->transportt);	\
  	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
  	if (i->f->get_##field)						\
  		i->f->get_##field(starget);				\
  	return snprintf(buf, 20, format_string, tp->field);		\
  }
  
  #define spi_transport_store_function(field, format_string)		\
  static ssize_t								\

  store_spi_transport_##field(struct device *dev, 			\
  			    struct device_attribute *attr,		\
  			    const char *buf, size_t count)		\

  {									\
  	int val;							\

  	struct scsi_target *starget = transport_class_to_starget(dev);	\

  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
  	struct spi_internal *i = to_spi_internal(shost->transportt);	\
  									\

  	if (!i->f->set_##field)						\
  		return -EINVAL;						\

  	val = simple_strtoul(buf, NULL, 0);				\

  	i->f->set_##field(starget, val);				\

  	return count;							\
  }
  
  #define spi_transport_store_max(field, format_string)			\
  static ssize_t								\

  store_spi_transport_##field(struct device *dev, 			\
  			    struct device_attribute *attr,		\
  			    const char *buf, size_t count)		\

  {									\
  	int val;							\

  	struct scsi_target *starget = transport_class_to_starget(dev);	\

  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
  	struct spi_internal *i = to_spi_internal(shost->transportt);	\
  	struct spi_transport_attrs *tp					\
  		= (struct spi_transport_attrs *)&starget->starget_data;	\
  									\

  	if (!i->f->set_##field)						\

  		return -EINVAL;						\

  	val = simple_strtoul(buf, NULL, 0);				\
  	if (val > tp->max_##field)					\
  		val = tp->max_##field;					\

  	i->f->set_##field(starget, val);				\
  	return count;							\
  }
  
  #define spi_transport_rd_attr(field, format_string)			\
  	spi_transport_show_function(field, format_string)		\
  	spi_transport_store_function(field, format_string)		\

  static DEVICE_ATTR(field, S_IRUGO,				\
  		   show_spi_transport_##field,			\
  		   store_spi_transport_##field);

  #define spi_transport_simple_attr(field, format_string)			\
  	spi_transport_show_simple(field, format_string)			\
  	spi_transport_store_simple(field, format_string)		\

  static DEVICE_ATTR(field, S_IRUGO,				\
  		   show_spi_transport_##field,			\
  		   store_spi_transport_##field);

  
  #define spi_transport_max_attr(field, format_string)			\
  	spi_transport_show_function(field, format_string)		\
  	spi_transport_store_max(field, format_string)			\
  	spi_transport_simple_attr(max_##field, format_string)		\

  static DEVICE_ATTR(field, S_IRUGO,				\
  		   show_spi_transport_##field,			\
  		   store_spi_transport_##field);

  /* The Parallel SCSI Tranport Attributes: */

  spi_transport_max_attr(offset, "%d
  ");
  spi_transport_max_attr(width, "%d
  ");

  spi_transport_max_attr(iu, "%d
  ");

  spi_transport_rd_attr(dt, "%d
  ");

  spi_transport_max_attr(qas, "%d
  ");

  spi_transport_rd_attr(wr_flow, "%d
  ");
  spi_transport_rd_attr(rd_strm, "%d
  ");
  spi_transport_rd_attr(rti, "%d
  ");
  spi_transport_rd_attr(pcomp_en, "%d
  ");

  spi_transport_rd_attr(hold_mcs, "%d
  ");

  /* we only care about the first child device that's a real SCSI device
   * so we return 1 to terminate the iteration when we find it */

  static int child_iter(struct device *dev, void *data)
  {

  	if (!scsi_is_sdev_device(dev))
  		return 0;

  	spi_dv_device(to_scsi_device(dev));

  	return 1;
  }

  static ssize_t

  store_spi_revalidate(struct device *dev, struct device_attribute *attr,
  		     const char *buf, size_t count)

  {

  	struct scsi_target *starget = transport_class_to_starget(dev);

  	device_for_each_child(&starget->dev, NULL, child_iter);

  	return count;
  }

  static DEVICE_ATTR(revalidate, S_IWUSR, NULL, store_spi_revalidate);

  
  /* Translate the period into ns according to the current spec
   * for SDTR/PPR messages */

  static int period_to_str(char *buf, int period)

  {

  	int len, picosec;

  	if (period < 0 || period > 0xff) {

  		picosec = -1;

  	} else if (period <= SPI_STATIC_PPR) {
  		picosec = ppr_to_ps[period];

  	} else {

  		picosec = period * 4000;

  	}
  
  	if (picosec == -1) {
  		len = sprintf(buf, "reserved");
  	} else {
  		len = sprint_frac(buf, picosec, 1000);
  	}

  	return len;
  }
  
  static ssize_t

  show_spi_transport_period_helper(char *buf, int period)

  {
  	int len = period_to_str(buf, period);

  	buf[len++] = '
  ';
  	buf[len] = '\0';
  	return len;
  }
  
  static ssize_t

  store_spi_transport_period_helper(struct device *dev, const char *buf,

  				  size_t count, int *periodp)

  {

  	int j, picosec, period = -1;
  	char *endp;
  
  	picosec = simple_strtoul(buf, &endp, 10) * 1000;
  	if (*endp == '.') {
  		int mult = 100;
  		do {
  			endp++;
  			if (!isdigit(*endp))
  				break;
  			picosec += (*endp - '0') * mult;
  			mult /= 10;
  		} while (mult > 0);
  	}
  
  	for (j = 0; j <= SPI_STATIC_PPR; j++) {
  		if (ppr_to_ps[j] < picosec)
  			continue;
  		period = j;
  		break;
  	}
  
  	if (period == -1)
  		period = picosec / 4000;
  
  	if (period > 0xff)
  		period = 0xff;

  	*periodp = period;

  
  	return count;
  }

  static ssize_t

  show_spi_transport_period(struct device *dev,
  			  struct device_attribute *attr, char *buf)

  {

  	struct scsi_target *starget = transport_class_to_starget(dev);

  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
  	struct spi_internal *i = to_spi_internal(shost->transportt);
  	struct spi_transport_attrs *tp =
  		(struct spi_transport_attrs *)&starget->starget_data;
  
  	if (i->f->get_period)
  		i->f->get_period(starget);

  	return show_spi_transport_period_helper(buf, tp->period);

  }
  
  static ssize_t

  store_spi_transport_period(struct device *cdev, struct device_attribute *attr,
  			   const char *buf, size_t count)

  {
  	struct scsi_target *starget = transport_class_to_starget(cdev);
  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
  	struct spi_internal *i = to_spi_internal(shost->transportt);
  	struct spi_transport_attrs *tp =
  		(struct spi_transport_attrs *)&starget->starget_data;
  	int period, retval;

  	if (!i->f->set_period)
  		return -EINVAL;

  	retval = store_spi_transport_period_helper(cdev, buf, count, &period);
  
  	if (period < tp->min_period)
  		period = tp->min_period;
  
  	i->f->set_period(starget, period);
  
  	return retval;
  }

  static DEVICE_ATTR(period, S_IRUGO,
  		   show_spi_transport_period,
  		   store_spi_transport_period);

  static ssize_t

  show_spi_transport_min_period(struct device *cdev,
  			      struct device_attribute *attr, char *buf)

  {
  	struct scsi_target *starget = transport_class_to_starget(cdev);

  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
  	struct spi_internal *i = to_spi_internal(shost->transportt);

  	struct spi_transport_attrs *tp =
  		(struct spi_transport_attrs *)&starget->starget_data;

  	if (!i->f->set_period)
  		return -EINVAL;

  	return show_spi_transport_period_helper(buf, tp->min_period);

  }
  
  static ssize_t

  store_spi_transport_min_period(struct device *cdev,
  			       struct device_attribute *attr,
  			       const char *buf, size_t count)

  {
  	struct scsi_target *starget = transport_class_to_starget(cdev);
  	struct spi_transport_attrs *tp =
  		(struct spi_transport_attrs *)&starget->starget_data;
  
  	return store_spi_transport_period_helper(cdev, buf, count,
  						 &tp->min_period);
  }

  static DEVICE_ATTR(min_period, S_IRUGO,
  		   show_spi_transport_min_period,
  		   store_spi_transport_min_period);

  static ssize_t show_spi_host_signalling(struct device *cdev,
  					struct device_attribute *attr,
  					char *buf)

  {
  	struct Scsi_Host *shost = transport_class_to_shost(cdev);
  	struct spi_internal *i = to_spi_internal(shost->transportt);
  
  	if (i->f->get_signalling)
  		i->f->get_signalling(shost);
  
  	return sprintf(buf, "%s
  ", spi_signal_to_string(spi_signalling(shost)));
  }

  static ssize_t store_spi_host_signalling(struct device *dev,
  					 struct device_attribute *attr,

  					 const char *buf, size_t count)
  {

  	struct Scsi_Host *shost = transport_class_to_shost(dev);

  	struct spi_internal *i = to_spi_internal(shost->transportt);
  	enum spi_signal_type type = spi_signal_to_value(buf);

  	if (!i->f->set_signalling)
  		return -EINVAL;

  	if (type != SPI_SIGNAL_UNKNOWN)
  		i->f->set_signalling(shost, type);
  
  	return count;
  }

  static DEVICE_ATTR(signalling, S_IRUGO,
  		   show_spi_host_signalling,
  		   store_spi_host_signalling);

  static ssize_t show_spi_host_width(struct device *cdev,
  				      struct device_attribute *attr,
  				      char *buf)
  {
  	struct Scsi_Host *shost = transport_class_to_shost(cdev);
  
  	return sprintf(buf, "%s
  ", shost->max_id == 16 ? "wide" : "narrow");
  }
  static DEVICE_ATTR(host_width, S_IRUGO,
  		   show_spi_host_width, NULL);
  
  static ssize_t show_spi_host_hba_id(struct device *cdev,
  				    struct device_attribute *attr,
  				    char *buf)
  {
  	struct Scsi_Host *shost = transport_class_to_shost(cdev);
  
  	return sprintf(buf, "%d
  ", shost->this_id);
  }
  static DEVICE_ATTR(hba_id, S_IRUGO,
  		   show_spi_host_hba_id, NULL);

  #define DV_SET(x, y)			\
  	if(i->f->set_##x)		\
  		i->f->set_##x(sdev->sdev_target, y)

  enum spi_compare_returns {
  	SPI_COMPARE_SUCCESS,
  	SPI_COMPARE_FAILURE,
  	SPI_COMPARE_SKIP_TEST,
  };
  
  
  /* This is for read/write Domain Validation:  If the device supports
   * an echo buffer, we do read/write tests to it */
  static enum spi_compare_returns

  spi_dv_device_echo_buffer(struct scsi_device *sdev, u8 *buffer,

  			  u8 *ptr, const int retries)
  {

  	int len = ptr - buffer;

  	int j, k, r, result;

  	unsigned int pattern = 0x0000ffff;

  	struct scsi_sense_hdr sshdr;

  
  	const char spi_write_buffer[] = {
  		WRITE_BUFFER, 0x0a, 0, 0, 0, 0, 0, len >> 8, len & 0xff, 0
  	};
  	const char spi_read_buffer[] = {
  		READ_BUFFER, 0x0a, 0, 0, 0, 0, 0, len >> 8, len & 0xff, 0
  	};
  
  	/* set up the pattern buffer.  Doesn't matter if we spill
  	 * slightly beyond since that's where the read buffer is */
  	for (j = 0; j < len; ) {
  
  		/* fill the buffer with counting (test a) */
  		for ( ; j < min(len, 32); j++)
  			buffer[j] = j;
  		k = j;
  		/* fill the buffer with alternating words of 0x0 and
  		 * 0xffff (test b) */
  		for ( ; j < min(len, k + 32); j += 2) {
  			u16 *word = (u16 *)&buffer[j];
  			
  			*word = (j & 0x02) ? 0x0000 : 0xffff;
  		}
  		k = j;
  		/* fill with crosstalk (alternating 0x5555 0xaaa)
                   * (test c) */
  		for ( ; j < min(len, k + 32); j += 2) {
  			u16 *word = (u16 *)&buffer[j];
  
  			*word = (j & 0x02) ? 0x5555 : 0xaaaa;
  		}
  		k = j;
  		/* fill with shifting bits (test d) */
  		for ( ; j < min(len, k + 32); j += 4) {
  			u32 *word = (unsigned int *)&buffer[j];
  			u32 roll = (pattern & 0x80000000) ? 1 : 0;
  			
  			*word = pattern;
  			pattern = (pattern << 1) | roll;
  		}
  		/* don't bother with random data (test e) */
  	}
  
  	for (r = 0; r < retries; r++) {

  		result = spi_execute(sdev, spi_write_buffer, DMA_TO_DEVICE,
  				     buffer, len, &sshdr);
  		if(result || !scsi_device_online(sdev)) {

  
  			scsi_device_set_state(sdev, SDEV_QUIESCE);

  			if (scsi_sense_valid(&sshdr)

  			    && sshdr.sense_key == ILLEGAL_REQUEST
  			    /* INVALID FIELD IN CDB */
  			    && sshdr.asc == 0x24 && sshdr.ascq == 0x00)
  				/* This would mean that the drive lied
  				 * to us about supporting an echo
  				 * buffer (unfortunately some Western
  				 * Digital drives do precisely this)
  				 */
  				return SPI_COMPARE_SKIP_TEST;

  			sdev_printk(KERN_ERR, sdev, "Write Buffer failure %x
  ", result);

  			return SPI_COMPARE_FAILURE;
  		}
  
  		memset(ptr, 0, len);

  		spi_execute(sdev, spi_read_buffer, DMA_FROM_DEVICE,
  			    ptr, len, NULL);

  		scsi_device_set_state(sdev, SDEV_QUIESCE);
  
  		if (memcmp(buffer, ptr, len) != 0)
  			return SPI_COMPARE_FAILURE;
  	}
  	return SPI_COMPARE_SUCCESS;
  }
  
  /* This is for the simplest form of Domain Validation: a read test
   * on the inquiry data from the device */
  static enum spi_compare_returns

  spi_dv_device_compare_inquiry(struct scsi_device *sdev, u8 *buffer,

  			      u8 *ptr, const int retries)
  {

  	int r, result;
  	const int len = sdev->inquiry_len;

  	const char spi_inquiry[] = {
  		INQUIRY, 0, 0, 0, len, 0
  	};
  
  	for (r = 0; r < retries; r++) {

  		memset(ptr, 0, len);

  		result = spi_execute(sdev, spi_inquiry, DMA_FROM_DEVICE,
  				     ptr, len, NULL);

  		if(result || !scsi_device_online(sdev)) {

  			scsi_device_set_state(sdev, SDEV_QUIESCE);
  			return SPI_COMPARE_FAILURE;
  		}
  
  		/* If we don't have the inquiry data already, the
  		 * first read gets it */
  		if (ptr == buffer) {
  			ptr += len;
  			--r;
  			continue;
  		}
  
  		if (memcmp(buffer, ptr, len) != 0)
  			/* failure */
  			return SPI_COMPARE_FAILURE;
  	}
  	return SPI_COMPARE_SUCCESS;
  }
  
  static enum spi_compare_returns

  spi_dv_retrain(struct scsi_device *sdev, u8 *buffer, u8 *ptr,

  	       enum spi_compare_returns 

  	       (*compare_fn)(struct scsi_device *, u8 *, u8 *, int))

  {

  	struct spi_internal *i = to_spi_internal(sdev->host->transportt);

  	struct scsi_target *starget = sdev->sdev_target;

  	int period = 0, prevperiod = 0; 
  	enum spi_compare_returns retval;
  
  
  	for (;;) {
  		int newperiod;

  		retval = compare_fn(sdev, buffer, ptr, DV_LOOPS);

  
  		if (retval == SPI_COMPARE_SUCCESS
  		    || retval == SPI_COMPARE_SKIP_TEST)
  			break;
  
  		/* OK, retrain, fallback */

  		if (i->f->get_iu)
  			i->f->get_iu(starget);
  		if (i->f->get_qas)
  			i->f->get_qas(starget);

  		if (i->f->get_period)
  			i->f->get_period(sdev->sdev_target);

  
  		/* Here's the fallback sequence; first try turning off
  		 * IU, then QAS (if we can control them), then finally
  		 * fall down the periods */
  		if (i->f->set_iu && spi_iu(starget)) {

  			starget_printk(KERN_ERR, starget, "Domain Validation Disabling Information Units
  ");

  			DV_SET(iu, 0);
  		} else if (i->f->set_qas && spi_qas(starget)) {

  			starget_printk(KERN_ERR, starget, "Domain Validation Disabling Quick Arbitration and Selection
  ");

  			DV_SET(qas, 0);
  		} else {
  			newperiod = spi_period(starget);
  			period = newperiod > period ? newperiod : period;
  			if (period < 0x0d)
  				period++;
  			else
  				period += period >> 1;
  
  			if (unlikely(period > 0xff || period == prevperiod)) {
  				/* Total failure; set to async and return */

  				starget_printk(KERN_ERR, starget, "Domain Validation Failure, dropping back to Asynchronous
  ");

  				DV_SET(offset, 0);
  				return SPI_COMPARE_FAILURE;
  			}

  			starget_printk(KERN_ERR, starget, "Domain Validation detected failure, dropping back
  ");

  			DV_SET(period, period);
  			prevperiod = period;

  		}

  	}
  	return retval;
  }
  
  static int

  spi_dv_device_get_echo_buffer(struct scsi_device *sdev, u8 *buffer)

  {

  	int l, result;

  
  	/* first off do a test unit ready.  This can error out 
  	 * because of reservations or some other reason.  If it
  	 * fails, the device won't let us write to the echo buffer
  	 * so just return failure */
  	

  	static const char spi_test_unit_ready[] = {

  		TEST_UNIT_READY, 0, 0, 0, 0, 0
  	};

  	static const char spi_read_buffer_descriptor[] = {

  		READ_BUFFER, 0x0b, 0, 0, 0, 0, 0, 0, 4, 0
  	};
  
  	

  	/* We send a set of three TURs to clear any outstanding 
  	 * unit attention conditions if they exist (Otherwise the
  	 * buffer tests won't be happy).  If the TUR still fails
  	 * (reservation conflict, device not ready, etc) just
  	 * skip the write tests */
  	for (l = 0; ; l++) {

  		result = spi_execute(sdev, spi_test_unit_ready, DMA_NONE, 
  				     NULL, 0, NULL);

  		if(result) {

  			if(l >= 3)
  				return 0;
  		} else {
  			/* TUR succeeded */
  			break;
  		}
  	}

  	result = spi_execute(sdev, spi_read_buffer_descriptor, 
  			     DMA_FROM_DEVICE, buffer, 4, NULL);

  	if (result)

  		/* Device has no echo buffer */
  		return 0;
  
  	return buffer[3] + ((buffer[2] & 0x1f) << 8);
  }
  
  static void

  spi_dv_device_internal(struct scsi_device *sdev, u8 *buffer)

  {

  	struct spi_internal *i = to_spi_internal(sdev->host->transportt);

  	struct scsi_target *starget = sdev->sdev_target;

  	struct Scsi_Host *shost = sdev->host;

  	int len = sdev->inquiry_len;

  	int min_period = spi_min_period(starget);
  	int max_width = spi_max_width(starget);

  	/* first set us up for narrow async */
  	DV_SET(offset, 0);
  	DV_SET(width, 0);

  	if (spi_dv_device_compare_inquiry(sdev, buffer, buffer, DV_LOOPS)

  	    != SPI_COMPARE_SUCCESS) {

  		starget_printk(KERN_ERR, starget, "Domain Validation Initial Inquiry Failed
  ");

  		/* FIXME: should probably offline the device here? */
  		return;
  	}

  	if (!spi_support_wide(starget)) {

  		spi_max_width(starget) = 0;
  		max_width = 0;
  	}

  	/* test width */

  	if (i->f->set_width && max_width) {

  		i->f->set_width(starget, 1);

  		if (spi_dv_device_compare_inquiry(sdev, buffer,

  						   buffer + len,
  						   DV_LOOPS)
  		    != SPI_COMPARE_SUCCESS) {

  			starget_printk(KERN_ERR, starget, "Wide Transfers Fail
  ");

  			i->f->set_width(starget, 0);

  			/* Make sure we don't force wide back on by asking
  			 * for a transfer period that requires it */
  			max_width = 0;
  			if (min_period < 10)
  				min_period = 10;

  		}
  	}
  
  	if (!i->f->set_period)
  		return;
  
  	/* device can't handle synchronous */

  	if (!spi_support_sync(starget) && !spi_support_dt(starget))

  		return;

  	/* len == -1 is the signal that we need to ascertain the
  	 * presence of an echo buffer before trying to use it.  len ==
  	 * 0 means we don't have an echo buffer */
  	len = -1;

  
   retry:
  
  	/* now set up to the maximum */

  	DV_SET(offset, spi_max_offset(starget));

  	DV_SET(period, min_period);

  	/* try QAS requests; this should be harmless to set if the
  	 * target supports it */

  	if (spi_support_qas(starget) && spi_max_qas(starget)) {

  		DV_SET(qas, 1);

  	} else {
  		DV_SET(qas, 0);
  	}

  	if (spi_support_ius(starget) && spi_max_iu(starget) &&
  	    min_period < 9) {

  		/* This u320 (or u640). Set IU transfers */

  		DV_SET(iu, 1);

  		/* Then set the optional parameters */

  		DV_SET(rd_strm, 1);
  		DV_SET(wr_flow, 1);
  		DV_SET(rti, 1);

  		if (min_period == 8)

  			DV_SET(pcomp_en, 1);

  	} else {
  		DV_SET(iu, 0);

  	}

  	/* now that we've done all this, actually check the bus
  	 * signal type (if known).  Some devices are stupid on
  	 * a SE bus and still claim they can try LVD only settings */
  	if (i->f->get_signalling)
  		i->f->get_signalling(shost);
  	if (spi_signalling(shost) == SPI_SIGNAL_SE ||

  	    spi_signalling(shost) == SPI_SIGNAL_HVD ||

  	    !spi_support_dt(starget)) {

  		DV_SET(dt, 0);

  	} else {
  		DV_SET(dt, 1);
  	}

  	/* set width last because it will pull all the other
  	 * parameters down to required values */
  	DV_SET(width, max_width);

  	/* Do the read only INQUIRY tests */
  	spi_dv_retrain(sdev, buffer, buffer + sdev->inquiry_len,
  		       spi_dv_device_compare_inquiry);
  	/* See if we actually managed to negotiate and sustain DT */
  	if (i->f->get_dt)
  		i->f->get_dt(starget);
  
  	/* see if the device has an echo buffer.  If it does we can do
  	 * the SPI pattern write tests.  Because of some broken
  	 * devices, we *only* try this on a device that has actually
  	 * negotiated DT */
  
  	if (len == -1 && spi_dt(starget))
  		len = spi_dv_device_get_echo_buffer(sdev, buffer);

  	if (len <= 0) {

  		starget_printk(KERN_INFO, starget, "Domain Validation skipping write tests
  ");

  		return;
  	}
  
  	if (len > SPI_MAX_ECHO_BUFFER_SIZE) {

  		starget_printk(KERN_WARNING, starget, "Echo buffer size %d is too big, trimming to %d
  ", len, SPI_MAX_ECHO_BUFFER_SIZE);

  		len = SPI_MAX_ECHO_BUFFER_SIZE;
  	}

  	if (spi_dv_retrain(sdev, buffer, buffer + len,

  			   spi_dv_device_echo_buffer)
  	    == SPI_COMPARE_SKIP_TEST) {
  		/* OK, the stupid drive can't do a write echo buffer
  		 * test after all, fall back to the read tests */
  		len = 0;
  		goto retry;
  	}
  }
  
  
  /**	spi_dv_device - Do Domain Validation on the device
   *	@sdev:		scsi device to validate
   *
   *	Performs the domain validation on the given device in the
   *	current execution thread.  Since DV operations may sleep,
   *	the current thread must have user context.  Also no SCSI
   *	related locks that would deadlock I/O issued by the DV may
   *	be held.
   */
  void
  spi_dv_device(struct scsi_device *sdev)
  {

  	struct scsi_target *starget = sdev->sdev_target;
  	u8 *buffer;
  	const int len = SPI_MAX_ECHO_BUFFER_SIZE*2;

  	/*
  	 * Because this function and the power management code both call
  	 * scsi_device_quiesce(), it is not safe to perform domain validation
  	 * while suspend or resume is in progress. Hence the
  	 * lock/unlock_system_sleep() calls.
  	 */
  	lock_system_sleep();

  	if (unlikely(spi_dv_in_progress(starget)))

  		goto unlock;

  	if (unlikely(scsi_device_get(sdev)))

  		goto unlock;

  	spi_dv_in_progress(starget) = 1;

  	buffer = kzalloc(len, GFP_KERNEL);

  
  	if (unlikely(!buffer))
  		goto out_put;

  	/* We need to verify that the actual device will quiesce; the
  	 * later target quiesce is just a nice to have */
  	if (unlikely(scsi_device_quiesce(sdev)))
  		goto out_free;
  
  	scsi_target_quiesce(starget);
  
  	spi_dv_pending(starget) = 1;

  	mutex_lock(&spi_dv_mutex(starget));

  	starget_printk(KERN_INFO, starget, "Beginning Domain Validation
  ");

  	spi_dv_device_internal(sdev, buffer);

  	starget_printk(KERN_INFO, starget, "Ending Domain Validation
  ");

  	mutex_unlock(&spi_dv_mutex(starget));

  	spi_dv_pending(starget) = 0;
  
  	scsi_target_resume(starget);
  
  	spi_initial_dv(starget) = 1;
  
   out_free:
  	kfree(buffer);
   out_put:

  	spi_dv_in_progress(starget) = 0;

  	scsi_device_put(sdev);

  unlock:
  	unlock_system_sleep();

  }
  EXPORT_SYMBOL(spi_dv_device);
  
  struct work_queue_wrapper {
  	struct work_struct	work;
  	struct scsi_device	*sdev;
  };
  
  static void

  spi_dv_device_work_wrapper(struct work_struct *work)

  {

  	struct work_queue_wrapper *wqw =
  		container_of(work, struct work_queue_wrapper, work);

  	struct scsi_device *sdev = wqw->sdev;
  
  	kfree(wqw);
  	spi_dv_device(sdev);
  	spi_dv_pending(sdev->sdev_target) = 0;
  	scsi_device_put(sdev);
  }
  
  
  /**
   *	spi_schedule_dv_device - schedule domain validation to occur on the device
   *	@sdev:	The device to validate
   *
   *	Identical to spi_dv_device() above, except that the DV will be
   *	scheduled to occur in a workqueue later.  All memory allocations
   *	are atomic, so may be called from any context including those holding
   *	SCSI locks.
   */
  void
  spi_schedule_dv_device(struct scsi_device *sdev)
  {
  	struct work_queue_wrapper *wqw =
  		kmalloc(sizeof(struct work_queue_wrapper), GFP_ATOMIC);
  
  	if (unlikely(!wqw))
  		return;
  
  	if (unlikely(spi_dv_pending(sdev->sdev_target))) {
  		kfree(wqw);
  		return;
  	}
  	/* Set pending early (dv_device doesn't check it, only sets it) */
  	spi_dv_pending(sdev->sdev_target) = 1;
  	if (unlikely(scsi_device_get(sdev))) {
  		kfree(wqw);
  		spi_dv_pending(sdev->sdev_target) = 0;
  		return;
  	}

  	INIT_WORK(&wqw->work, spi_dv_device_work_wrapper);

  	wqw->sdev = sdev;
  
  	schedule_work(&wqw->work);
  }
  EXPORT_SYMBOL(spi_schedule_dv_device);
  
  /**
   * spi_display_xfer_agreement - Print the current target transfer agreement
   * @starget: The target for which to display the agreement
   *
   * Each SPI port is required to maintain a transfer agreement for each
   * other port on the bus.  This function prints a one-line summary of
   * the current agreement; more detailed information is available in sysfs.
   */
  void spi_display_xfer_agreement(struct scsi_target *starget)
  {
  	struct spi_transport_attrs *tp;
  	tp = (struct spi_transport_attrs *)&starget->starget_data;
  
  	if (tp->offset > 0 && tp->period > 0) {
  		unsigned int picosec, kb100;
  		char *scsi = "FAST-?";
  		char tmp[8];
  
  		if (tp->period <= SPI_STATIC_PPR) {
  			picosec = ppr_to_ps[tp->period];
  			switch (tp->period) {
  				case  7: scsi = "FAST-320"; break;
  				case  8: scsi = "FAST-160"; break;
  				case  9: scsi = "FAST-80"; break;
  				case 10:
  				case 11: scsi = "FAST-40"; break;
  				case 12: scsi = "FAST-20"; break;
  			}
  		} else {
  			picosec = tp->period * 4000;
  			if (tp->period < 25)
  				scsi = "FAST-20";
  			else if (tp->period < 50)
  				scsi = "FAST-10";
  			else
  				scsi = "FAST-5";
  		}
  
  		kb100 = (10000000 + picosec / 2) / picosec;
  		if (tp->width)
  			kb100 *= 2;
  		sprint_frac(tmp, picosec, 1000);
  
  		dev_info(&starget->dev,

  			 "%s %sSCSI %d.%d MB/s %s%s%s%s%s%s%s%s (%s ns, offset %d)
  ",
  			 scsi, tp->width ? "WIDE " : "", kb100/10, kb100 % 10,
  			 tp->dt ? "DT" : "ST",
  			 tp->iu ? " IU" : "",
  			 tp->qas  ? " QAS" : "",
  			 tp->rd_strm ? " RDSTRM" : "",
  			 tp->rti ? " RTI" : "",
  			 tp->wr_flow ? " WRFLOW" : "",
  			 tp->pcomp_en ? " PCOMP" : "",
  			 tp->hold_mcs ? " HMCS" : "",
  			 tmp, tp->offset);

  	} else {

  		dev_info(&starget->dev, "%sasynchronous
  ",

  				tp->width ? "wide " : "");
  	}
  }
  EXPORT_SYMBOL(spi_display_xfer_agreement);

  int spi_populate_width_msg(unsigned char *msg, int width)
  {
  	msg[0] = EXTENDED_MESSAGE;
  	msg[1] = 2;
  	msg[2] = EXTENDED_WDTR;
  	msg[3] = width;
  	return 4;
  }

  EXPORT_SYMBOL_GPL(spi_populate_width_msg);

  
  int spi_populate_sync_msg(unsigned char *msg, int period, int offset)
  {
  	msg[0] = EXTENDED_MESSAGE;
  	msg[1] = 3;
  	msg[2] = EXTENDED_SDTR;
  	msg[3] = period;
  	msg[4] = offset;
  	return 5;
  }

  EXPORT_SYMBOL_GPL(spi_populate_sync_msg);

  
  int spi_populate_ppr_msg(unsigned char *msg, int period, int offset,
  		int width, int options)
  {
  	msg[0] = EXTENDED_MESSAGE;
  	msg[1] = 6;
  	msg[2] = EXTENDED_PPR;
  	msg[3] = period;
  	msg[4] = 0;
  	msg[5] = offset;
  	msg[6] = width;
  	msg[7] = options;
  	return 8;
  }

  EXPORT_SYMBOL_GPL(spi_populate_ppr_msg);

  /**
   * spi_populate_tag_msg - place a tag message in a buffer
   * @msg:	pointer to the area to place the tag
   * @cmd:	pointer to the scsi command for the tag
   *
   * Notes:
   *	designed to create the correct type of tag message for the 
   *	particular request.  Returns the size of the tag message.
   *	May return 0 if TCQ is disabled for this device.
   **/
  int spi_populate_tag_msg(unsigned char *msg, struct scsi_cmnd *cmd)
  {
          if (cmd->flags & SCMD_TAGGED) {

  		*msg++ = SIMPLE_QUEUE_TAG;

          	*msg++ = cmd->request->tag;
          	return 2;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(spi_populate_tag_msg);

  #ifdef CONFIG_SCSI_CONSTANTS
  static const char * const one_byte_msgs[] = {

  /* 0x00 */ "Task Complete", NULL /* Extended Message */, "Save Pointers",

  /* 0x03 */ "Restore Pointers", "Disconnect", "Initiator Error", 

  /* 0x06 */ "Abort Task Set", "Message Reject", "Nop", "Message Parity Error",

  /* 0x0a */ "Linked Command Complete", "Linked Command Complete w/flag",

  /* 0x0c */ "Target Reset", "Abort Task", "Clear Task Set", 
  /* 0x0f */ "Initiate Recovery", "Release Recovery",
  /* 0x11 */ "Terminate Process", "Continue Task", "Target Transfer Disable",
  /* 0x14 */ NULL, NULL, "Clear ACA", "LUN Reset"

  };

  
  static const char * const two_byte_msgs[] = {

  /* 0x20 */ "Simple Queue Tag", "Head of Queue Tag", "Ordered Queue Tag",

  /* 0x23 */ "Ignore Wide Residue", "ACA"

  };

  
  static const char * const extended_msgs[] = {
  /* 0x00 */ "Modify Data Pointer", "Synchronous Data Transfer Request",

  /* 0x02 */ "SCSI-I Extended Identify", "Wide Data Transfer Request",

  /* 0x04 */ "Parallel Protocol Request", "Modify Bidirectional Data Pointer"

  };

  static void print_nego(const unsigned char *msg, int per, int off, int width)

  {
  	if (per) {
  		char buf[20];
  		period_to_str(buf, msg[per]);
  		printk("period = %s ns ", buf);
  	}
  
  	if (off)
  		printk("offset = %d ", msg[off]);
  	if (width)
  		printk("width = %d ", 8 << msg[width]);
  }

  static void print_ptr(const unsigned char *msg, int msb, const char *desc)
  {
  	int ptr = (msg[msb] << 24) | (msg[msb+1] << 16) | (msg[msb+2] << 8) |
  			msg[msb+3];
  	printk("%s = %d ", desc, ptr);
  }

  int spi_print_msg(const unsigned char *msg)

  {

  	int len = 1, i;

  	if (msg[0] == EXTENDED_MESSAGE) {

  		len = 2 + msg[1];
  		if (len == 2)
  			len += 256;

  		if (msg[2] < ARRAY_SIZE(extended_msgs))

  			printk ("%s ", extended_msgs[msg[2]]); 
  		else 
  			printk ("Extended Message, reserved code (0x%02x) ",
  				(int) msg[2]);
  		switch (msg[2]) {
  		case EXTENDED_MODIFY_DATA_POINTER:

  			print_ptr(msg, 3, "pointer");

  			break;
  		case EXTENDED_SDTR:

  			print_nego(msg, 3, 4, 0);

  			break;
  		case EXTENDED_WDTR:

  			print_nego(msg, 0, 0, 3);
  			break;
  		case EXTENDED_PPR:
  			print_nego(msg, 3, 5, 6);

  			break;

  		case EXTENDED_MODIFY_BIDI_DATA_PTR:
  			print_ptr(msg, 3, "out");
  			print_ptr(msg, 7, "in");
  			break;

  		default:
  		for (i = 2; i < len; ++i) 
  			printk("%02x ", msg[i]);
  		}
  	/* Identify */
  	} else if (msg[0] & 0x80) {
  		printk("Identify disconnect %sallowed %s %d ",
  			(msg[0] & 0x40) ? "" : "not ",
  			(msg[0] & 0x20) ? "target routine" : "lun",
  			msg[0] & 0x7);

  	/* Normal One byte */
  	} else if (msg[0] < 0x1f) {

  		if (msg[0] < ARRAY_SIZE(one_byte_msgs) && one_byte_msgs[msg[0]])

  			printk("%s ", one_byte_msgs[msg[0]]);

  		else
  			printk("reserved (%02x) ", msg[0]);

  	} else if (msg[0] == 0x55) {
  		printk("QAS Request ");

  	/* Two byte */
  	} else if (msg[0] <= 0x2f) {

  		if ((msg[0] - 0x20) < ARRAY_SIZE(two_byte_msgs))

  			printk("%s %02x ", two_byte_msgs[msg[0] - 0x20], 
  				msg[1]);
  		else 
  			printk("reserved two byte (%02x %02x) ", 
  				msg[0], msg[1]);
  		len = 2;
  	} else 

  		printk("reserved ");

  	return len;
  }

  EXPORT_SYMBOL(spi_print_msg);

  
  #else  /* ifndef CONFIG_SCSI_CONSTANTS */

  int spi_print_msg(const unsigned char *msg)

  {

  	int len = 1, i;

  
  	if (msg[0] == EXTENDED_MESSAGE) {

  		len = 2 + msg[1];
  		if (len == 2)
  			len += 256;

  		for (i = 0; i < len; ++i)
  			printk("%02x ", msg[i]);
  	/* Identify */
  	} else if (msg[0] & 0x80) {
  		printk("%02x ", msg[0]);

  	/* Normal One byte */

  	} else if ((msg[0] < 0x1f) || (msg[0] == 0x55)) {

  		printk("%02x ", msg[0]);

  	/* Two byte */
  	} else if (msg[0] <= 0x2f) {
  		printk("%02x %02x", msg[0], msg[1]);
  		len = 2;
  	} else 
  		printk("%02x ", msg[0]);
  	return len;
  }

  EXPORT_SYMBOL(spi_print_msg);

  #endif /* ! CONFIG_SCSI_CONSTANTS */

  static int spi_device_match(struct attribute_container *cont,
  			    struct device *dev)
  {
  	struct scsi_device *sdev;
  	struct Scsi_Host *shost;

  	struct spi_internal *i;

  
  	if (!scsi_is_sdev_device(dev))
  		return 0;
  
  	sdev = to_scsi_device(dev);
  	shost = sdev->host;
  	if (!shost->transportt  || shost->transportt->host_attrs.ac.class
  	    != &spi_host_class.class)
  		return 0;
  	/* Note: this class has no device attributes, so it has
  	 * no per-HBA allocation and thus we don't need to distinguish
  	 * the attribute containers for the device */

  	i = to_spi_internal(shost->transportt);
  	if (i->f->deny_binding && i->f->deny_binding(sdev->sdev_target))
  		return 0;

  	return 1;
  }
  
  static int spi_target_match(struct attribute_container *cont,
  			    struct device *dev)
  {
  	struct Scsi_Host *shost;

  	struct scsi_target *starget;

  	struct spi_internal *i;
  
  	if (!scsi_is_target_device(dev))
  		return 0;
  
  	shost = dev_to_shost(dev->parent);
  	if (!shost->transportt  || shost->transportt->host_attrs.ac.class
  	    != &spi_host_class.class)
  		return 0;
  
  	i = to_spi_internal(shost->transportt);

  	starget = to_scsi_target(dev);
  
  	if (i->f->deny_binding && i->f->deny_binding(starget))
  		return 0;

  	return &i->t.target_attrs.ac == cont;
  }
  
  static DECLARE_TRANSPORT_CLASS(spi_transport_class,
  			       "spi_transport",
  			       spi_setup_transport_attrs,
  			       NULL,

  			       spi_target_configure);

  
  static DECLARE_ANON_TRANSPORT_CLASS(spi_device_class,
  				    spi_device_match,
  				    spi_device_configure);

  static struct attribute *host_attributes[] = {

  	&dev_attr_signalling.attr,

  	&dev_attr_host_width.attr,
  	&dev_attr_hba_id.attr,

  	NULL
  };
  
  static struct attribute_group host_attribute_group = {
  	.attrs = host_attributes,
  };
  
  static int spi_host_configure(struct transport_container *tc,
  			      struct device *dev,

  			      struct device *cdev)

  {
  	struct kobject *kobj = &cdev->kobj;
  	struct Scsi_Host *shost = transport_class_to_shost(cdev);
  	struct spi_internal *si = to_spi_internal(shost->transportt);

  	struct attribute *attr = &dev_attr_signalling.attr;

  	int rc = 0;
  
  	if (si->f->set_signalling)
  		rc = sysfs_chmod_file(kobj, attr, attr->mode | S_IWUSR);
  
  	return rc;
  }
  
  /* returns true if we should be showing the variable.  Also
   * overloads the return by setting 1<<1 if the attribute should
   * be writeable */
  #define TARGET_ATTRIBUTE_HELPER(name) \

  	(si->f->show_##name ? S_IRUGO : 0) | \
  	(si->f->set_##name ? S_IWUSR : 0)

  static umode_t target_attribute_is_visible(struct kobject *kobj,

  					  struct attribute *attr, int i)

  {

  	struct device *cdev = container_of(kobj, struct device, kobj);

  	struct scsi_target *starget = transport_class_to_starget(cdev);
  	struct Scsi_Host *shost = transport_class_to_shost(cdev);
  	struct spi_internal *si = to_spi_internal(shost->transportt);

  	if (attr == &dev_attr_period.attr &&

  	    spi_support_sync(starget))
  		return TARGET_ATTRIBUTE_HELPER(period);

  	else if (attr == &dev_attr_min_period.attr &&

  		 spi_support_sync(starget))
  		return TARGET_ATTRIBUTE_HELPER(period);

  	else if (attr == &dev_attr_offset.attr &&

  		 spi_support_sync(starget))
  		return TARGET_ATTRIBUTE_HELPER(offset);

  	else if (attr == &dev_attr_max_offset.attr &&

  		 spi_support_sync(starget))
  		return TARGET_ATTRIBUTE_HELPER(offset);

  	else if (attr == &dev_attr_width.attr &&

  		 spi_support_wide(starget))
  		return TARGET_ATTRIBUTE_HELPER(width);

  	else if (attr == &dev_attr_max_width.attr &&

  		 spi_support_wide(starget))
  		return TARGET_ATTRIBUTE_HELPER(width);

  	else if (attr == &dev_attr_iu.attr &&

  		 spi_support_ius(starget))
  		return TARGET_ATTRIBUTE_HELPER(iu);

  	else if (attr == &dev_attr_max_iu.attr &&
  		 spi_support_ius(starget))
  		return TARGET_ATTRIBUTE_HELPER(iu);

  	else if (attr == &dev_attr_dt.attr &&

  		 spi_support_dt(starget))
  		return TARGET_ATTRIBUTE_HELPER(dt);

  	else if (attr == &dev_attr_qas.attr &&

  		 spi_support_qas(starget))
  		return TARGET_ATTRIBUTE_HELPER(qas);

  	else if (attr == &dev_attr_max_qas.attr &&
  		 spi_support_qas(starget))
  		return TARGET_ATTRIBUTE_HELPER(qas);

  	else if (attr == &dev_attr_wr_flow.attr &&

  		 spi_support_ius(starget))
  		return TARGET_ATTRIBUTE_HELPER(wr_flow);

  	else if (attr == &dev_attr_rd_strm.attr &&

  		 spi_support_ius(starget))
  		return TARGET_ATTRIBUTE_HELPER(rd_strm);

  	else if (attr == &dev_attr_rti.attr &&

  		 spi_support_ius(starget))
  		return TARGET_ATTRIBUTE_HELPER(rti);

  	else if (attr == &dev_attr_pcomp_en.attr &&

  		 spi_support_ius(starget))
  		return TARGET_ATTRIBUTE_HELPER(pcomp_en);

  	else if (attr == &dev_attr_hold_mcs.attr &&

  		 spi_support_ius(starget))
  		return TARGET_ATTRIBUTE_HELPER(hold_mcs);

  	else if (attr == &dev_attr_revalidate.attr)

  		return S_IWUSR;

  
  	return 0;
  }
  
  static struct attribute *target_attributes[] = {

  	&dev_attr_period.attr,
  	&dev_attr_min_period.attr,
  	&dev_attr_offset.attr,
  	&dev_attr_max_offset.attr,
  	&dev_attr_width.attr,
  	&dev_attr_max_width.attr,
  	&dev_attr_iu.attr,

  	&dev_attr_max_iu.attr,

  	&dev_attr_dt.attr,
  	&dev_attr_qas.attr,

  	&dev_attr_max_qas.attr,

  	&dev_attr_wr_flow.attr,
  	&dev_attr_rd_strm.attr,
  	&dev_attr_rti.attr,
  	&dev_attr_pcomp_en.attr,
  	&dev_attr_hold_mcs.attr,
  	&dev_attr_revalidate.attr,

  	NULL
  };
  
  static struct attribute_group target_attribute_group = {
  	.attrs = target_attributes,
  	.is_visible = target_attribute_is_visible,
  };
  
  static int spi_target_configure(struct transport_container *tc,
  				struct device *dev,

  				struct device *cdev)

  {
  	struct kobject *kobj = &cdev->kobj;

  
  	/* force an update based on parameters read from the device */
  	sysfs_update_group(kobj, &target_attribute_group);

  
  	return 0;
  }

  struct scsi_transport_template *
  spi_attach_transport(struct spi_function_template *ft)
  {

  	struct spi_internal *i = kzalloc(sizeof(struct spi_internal),
  					 GFP_KERNEL);

  	if (unlikely(!i))
  		return NULL;

  	i->t.target_attrs.ac.class = &spi_transport_class.class;

  	i->t.target_attrs.ac.grp = &target_attribute_group;

  	i->t.target_attrs.ac.match = spi_target_match;
  	transport_container_register(&i->t.target_attrs);
  	i->t.target_size = sizeof(struct spi_transport_attrs);
  	i->t.host_attrs.ac.class = &spi_host_class.class;

  	i->t.host_attrs.ac.grp = &host_attribute_group;

  	i->t.host_attrs.ac.match = spi_host_match;
  	transport_container_register(&i->t.host_attrs);
  	i->t.host_size = sizeof(struct spi_host_attrs);
  	i->f = ft;

  	return &i->t;
  }
  EXPORT_SYMBOL(spi_attach_transport);
  
  void spi_release_transport(struct scsi_transport_template *t)
  {
  	struct spi_internal *i = to_spi_internal(t);
  
  	transport_container_unregister(&i->t.target_attrs);
  	transport_container_unregister(&i->t.host_attrs);
  
  	kfree(i);
  }
  EXPORT_SYMBOL(spi_release_transport);
  
  static __init int spi_transport_init(void)
  {

  	int error = scsi_dev_info_add_list(SCSI_DEVINFO_SPI,
  					   "SCSI Parallel Transport Class");
  	if (!error) {
  		int i;
  
  		for (i = 0; spi_static_device_list[i].vendor; i++)
  			scsi_dev_info_list_add_keyed(1,	/* compatible */
  						     spi_static_device_list[i].vendor,
  						     spi_static_device_list[i].model,
  						     NULL,
  						     spi_static_device_list[i].flags,
  						     SCSI_DEVINFO_SPI);
  	}
  
  	error = transport_class_register(&spi_transport_class);

  	if (error)
  		return error;
  	error = anon_transport_class_register(&spi_device_class);
  	return transport_class_register(&spi_host_class);
  }
  
  static void __exit spi_transport_exit(void)
  {
  	transport_class_unregister(&spi_transport_class);
  	anon_transport_class_unregister(&spi_device_class);
  	transport_class_unregister(&spi_host_class);

  	scsi_dev_info_remove_list(SCSI_DEVINFO_SPI);

  }
  
  MODULE_AUTHOR("Martin Hicks");
  MODULE_DESCRIPTION("SPI Transport Attributes");
  MODULE_LICENSE("GPL");
  
  module_init(spi_transport_init);
  module_exit(spi_transport_exit);