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scsi_transport_spi.c

/* 
 *  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>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#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 <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_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 */

/* 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;
      /* The actual attributes */
      struct class_device_attribute private_attrs[SPI_NUM_ATTRS];
      /* The array of null terminated pointers to attributes 
       * needed by scsi_sysfs.c */
      struct class_device_attribute *attrs[SPI_NUM_ATTRS + SPI_OTHER_ATTRS + 1];
      struct class_device_attribute private_host_attrs[SPI_HOST_ATTRS];
      struct class_device_attribute *host_attrs[SPI_HOST_ATTRS + 1];
};

#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];

      for(i = 0; i < DV_RETRIES; i++) {
            result = scsi_execute(sdev, cmd, dir, buffer, bufflen,
                              sense, DV_TIMEOUT, /* retries */ 1,
                              REQ_FAILFAST);
            if (result & DRIVER_SENSE) {
                  struct scsi_sense_hdr sshdr_tmp;
                  if (!sshdr)
                        sshdr = &sshdr_tmp;

                  if (scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE,
                                     sshdr)
                      && sshdr->sense_key == UNIT_ATTENTION)
                        continue;
            }
            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] == '\n' || 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 class_device *cdev)
{
      struct Scsi_Host *shost = dev_to_shost(dev);

      spi_signalling(shost) = SPI_SIGNAL_UNKNOWN;

      return 0;
}

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

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

      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;

      i = to_spi_internal(shost->transportt);
      
      return &i->t.host_attrs.ac == cont;
}

static int spi_device_configure(struct transport_container *tc,
                        struct device *dev,
                        struct class_device *cdev)
{
      struct scsi_device *sdev = to_scsi_device(dev);
      struct scsi_target *starget = sdev->sdev_target;

      /* 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);
      spi_support_qas(starget) = scsi_device_qas(sdev);

      return 0;
}

static int spi_setup_transport_attrs(struct transport_container *tc,
                             struct device *dev,
                             struct class_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_dt(starget) = 0;    /* ST */
      spi_qas(starget) = 0;
      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 class_device *cdev, char *buf)  \
{                                                     \
      struct scsi_target *starget = transport_class_to_starget(cdev);   \
      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 class_device *cdev, const char *buf, \
                      size_t count)                   \
{                                                     \
      int val;                                        \
      struct scsi_target *starget = transport_class_to_starget(cdev);   \
      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 class_device *cdev, char *buf)  \
{                                                     \
      struct scsi_target *starget = transport_class_to_starget(cdev);   \
      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 class_device *cdev, const char *buf, \
                      size_t count)                   \
{                                                     \
      int val;                                        \
      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);      \
                                                      \
      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 class_device *cdev, const char *buf, \
                      size_t count)                   \
{                                                     \
      int val;                                        \
      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;     \
                                                      \
      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 CLASS_DEVICE_ATTR(field, S_IRUGO | S_IWUSR,                \
                   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 CLASS_DEVICE_ATTR(field, S_IRUGO | S_IWUSR,                \
                   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 CLASS_DEVICE_ATTR(field, S_IRUGO | S_IWUSR,                \
                   show_spi_transport_##field,              \
                   store_spi_transport_##field);

/* The Parallel SCSI Tranport Attributes: */
spi_transport_max_attr(offset, "%d\n");
spi_transport_max_attr(width, "%d\n");
spi_transport_rd_attr(iu, "%d\n");
spi_transport_rd_attr(dt, "%d\n");
spi_transport_rd_attr(qas, "%d\n");
spi_transport_rd_attr(wr_flow, "%d\n");
spi_transport_rd_attr(rd_strm, "%d\n");
spi_transport_rd_attr(rti, "%d\n");
spi_transport_rd_attr(pcomp_en, "%d\n");
spi_transport_rd_attr(hold_mcs, "%d\n");

/* we only care about the first child device so we return 1 */
static int child_iter(struct device *dev, void *data)
{
      struct scsi_device *sdev = to_scsi_device(dev);

      spi_dv_device(sdev);
      return 1;
}

static ssize_t
store_spi_revalidate(struct class_device *cdev, const char *buf, size_t count)
{
      struct scsi_target *starget = transport_class_to_starget(cdev);

      device_for_each_child(&starget->dev, NULL, child_iter);
      return count;
}
static CLASS_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++] = '\n';
      buf[len] = '\0';
      return len;
}

static ssize_t
store_spi_transport_period_helper(struct class_device *cdev, 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 class_device *cdev, 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->get_period)
            i->f->get_period(starget);

      return show_spi_transport_period_helper(buf, tp->period);
}

static ssize_t
store_spi_transport_period(struct class_device *cdev, 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;

      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 CLASS_DEVICE_ATTR(period, S_IRUGO | S_IWUSR, 
                   show_spi_transport_period,
                   store_spi_transport_period);

static ssize_t
show_spi_transport_min_period(struct class_device *cdev, char *buf)
{
      struct scsi_target *starget = transport_class_to_starget(cdev);
      struct spi_transport_attrs *tp =
            (struct spi_transport_attrs *)&starget->starget_data;

      return show_spi_transport_period_helper(buf, tp->min_period);
}

static ssize_t
store_spi_transport_min_period(struct class_device *cdev, 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 CLASS_DEVICE_ATTR(min_period, S_IRUGO | S_IWUSR, 
                   show_spi_transport_min_period,
                   store_spi_transport_min_period);


static ssize_t show_spi_host_signalling(struct class_device *cdev, 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\n", spi_signal_to_string(spi_signalling(shost)));
}
static ssize_t store_spi_host_signalling(struct class_device *cdev,
                               const char *buf, size_t count)
{
      struct Scsi_Host *shost = transport_class_to_shost(cdev);
      struct spi_internal *i = to_spi_internal(shost->transportt);
      enum spi_signal_type type = spi_signal_to_value(buf);

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

      return count;
}
static CLASS_DEVICE_ATTR(signalling, S_IRUGO | S_IWUSR,
                   show_spi_host_signalling,
                   store_spi_host_signalling);

#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\n", 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 Disabing Information Units\n");
                  DV_SET(iu, 0);
            } else if (i->f->set_qas && spi_qas(starget)) {
                  starget_printk(KERN_ERR, starget, "Domain Validation Disabing Quick Arbitration and Selection\n");
                  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\n");
                        DV_SET(offset, 0);
                        return SPI_COMPARE_FAILURE;
                  }
                  starget_printk(KERN_ERR, starget, "Domain Validation detected failure, dropping back\n");
                  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 */
      
      const char spi_test_unit_ready[] = {
            TEST_UNIT_READY, 0, 0, 0, 0, 0
      };

      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\n");
            /* FIXME: should probably offline the device here? */
            return;
      }

      if (!scsi_device_wide(sdev)) {
            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\n");
                  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 (!scsi_device_sync(sdev) && !scsi_device_dt(sdev))
            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 (scsi_device_qas(sdev)) {
            DV_SET(qas, 1);
      } else {
            DV_SET(qas, 0);
      }

      if (scsi_device_ius(sdev) && 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 ||
          !scsi_device_dt(sdev)) {
            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\n");
            return;
      }

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

      if (unlikely(scsi_device_get(sdev)))
            return;

      if (unlikely(spi_dv_in_progress(starget)))
            return;
      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\n");

      spi_dv_device_internal(sdev, buffer);

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

      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);
}
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)\n",
                   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\n",
                        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);

#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 */

#define SETUP_ATTRIBUTE(field)                                    \
      i->private_attrs[count] = class_device_attr_##field;        \
      if (!i->f->set_##field) {                             \
            i->private_attrs[count].attr.mode = S_IRUGO;          \
            i->private_attrs[count].store = NULL;                 \
      }                                               \
      i->attrs[count] = &i->private_attrs[count];                 \
      if (i->f->show_##field)                               \
            count++

#define SETUP_RELATED_ATTRIBUTE(field, rel_field)                 \
      i->private_attrs[count] = class_device_attr_##field;        \
      if (!i->f->set_##rel_field) {                         \
            i->private_attrs[count].attr.mode = S_IRUGO;          \
            i->private_attrs[count].store = NULL;                 \
      }                                               \
      i->attrs[count] = &i->private_attrs[count];                 \
      if (i->f->show_##rel_field)                           \
            count++

#define SETUP_HOST_ATTRIBUTE(field)                         \
      i->private_host_attrs[count] = class_device_attr_##field;   \
      if (!i->f->set_##field) {                             \
            i->private_host_attrs[count].attr.mode = S_IRUGO;     \
            i->private_host_attrs[count].store = NULL;            \
      }                                               \
      i->host_attrs[count] = &i->private_host_attrs[count];       \
      count++

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,
                         NULL);

static DECLARE_ANON_TRANSPORT_CLASS(spi_device_class,
                            spi_device_match,
                            spi_device_configure);

struct scsi_transport_template *
spi_attach_transport(struct spi_function_template *ft)
{
      int count = 0;
      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.attrs = &i->attrs[0];
      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.attrs = &i->host_attrs[0];
      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;

      SETUP_ATTRIBUTE(period);
      SETUP_RELATED_ATTRIBUTE(min_period, period);
      SETUP_ATTRIBUTE(offset);
      SETUP_RELATED_ATTRIBUTE(max_offset, offset);
      SETUP_ATTRIBUTE(width);
      SETUP_RELATED_ATTRIBUTE(max_width, width);
      SETUP_ATTRIBUTE(iu);
      SETUP_ATTRIBUTE(dt);
      SETUP_ATTRIBUTE(qas);
      SETUP_ATTRIBUTE(wr_flow);
      SETUP_ATTRIBUTE(rd_strm);
      SETUP_ATTRIBUTE(rti);
      SETUP_ATTRIBUTE(pcomp_en);
      SETUP_ATTRIBUTE(hold_mcs);

      /* if you add an attribute but forget to increase SPI_NUM_ATTRS
       * this bug will trigger */
      BUG_ON(count > SPI_NUM_ATTRS);

      i->attrs[count++] = &class_device_attr_revalidate;

      i->attrs[count] = NULL;

      count = 0;
      SETUP_HOST_ATTRIBUTE(signalling);

      BUG_ON(count > SPI_HOST_ATTRS);

      i->host_attrs[count] = NULL;

      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 = 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);
}

MODULE_AUTHOR("Martin Hicks");
MODULE_DESCRIPTION("SPI Transport Attributes");
MODULE_LICENSE("GPL");

module_init(spi_transport_init);
module_exit(spi_transport_exit);

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