/* NeXTStep/OpenStep */
#endif
#include "../include/sane/sane.h"
#include "../include/sane/sanei_usb.h"
#include "../include/sane/saneopts.h"
#include "../include/sane/sanei_config.h"
#include "../include/sane/sanei_thread.h"
#include "../include/sane/sanei_backend.h"
#define RTCMD_GETREG		0x80
#define	RTCMD_READSRAM		0x81
#define	RTCMD_SETREG		0x88
#define	RTCMD_WRITESRAM		0x89
#define	RTCMD_NVRAMCONTROL	0x8a
#define	RTCMD_BYTESAVAIL	0x90
#define	RTCMD_READBYTES		0x91
#define	RT_CHANNEL_ALL		0
#define	RT_CHANNEL_RED		1
#define	RT_CHANNEL_GREEN	2
#define	RT_CHANNEL_BLUE		3
typedef int (*rts8801_callback) (void *param, unsigned bytes, void *data);
#define DEBUG 1
#define SCANNER_UNIT_TO_FIXED_MM(number) SANE_FIX(number * MM_PER_INCH / 1200)
#define FIXED_MM_TO_SCANNER_UNIT(number) SANE_UNFIX(number) * 1200 / MM_PER_INCH
#define MSG_ERR         1
#define MSG_USER        5
#define MSG_INFO        6
#define FLOW_CONTROL    10
#define MSG_IO          15
#define MSG_IO_READ     17
#define IO_CMD          20
#define IO_CMD_RES      20
#define MSG_GET         25
/* ------------------------------------------------------------------------- */
enum hp3500_option
{
  OPT_NUM_OPTS = 0,
  OPT_RESOLUTION,
  OPT_GEOMETRY_GROUP,
  OPT_TL_X,
  OPT_TL_Y,
  OPT_BR_X,
  OPT_BR_Y,
  OPT_MODE_GROUP,
  OPT_MODE,
  OPT_BRIGHTNESS,
  OPT_CONTRAST,
  OPT_GAMMA,
  NUM_OPTIONS
};
typedef struct
{
  int left;
  int top;
  int right;
  int bottom;
} hp3500_rect;
struct hp3500_data
{
  struct hp3500_data *next;
  char *devicename;
  int sfd;
  int pipe_r;
  int pipe_w;
  SANE_Pid reader_pid;
  int resolution;
  int mode;
  time_t last_scan;
  hp3500_rect request_mm;
  hp3500_rect actual_mm;
  hp3500_rect fullres_pixels;
  hp3500_rect actres_pixels;
  int rounded_left;
  int rounded_top;
  int rounded_right;
  int rounded_bottom;
  int bytes_per_scan_line;
  int scan_width_pixels;
  int scan_height_pixels;
  int brightness;
  int contrast;
  double gamma;
  SANE_Option_Descriptor opt[NUM_OPTIONS];
  SANE_Device sane;
};
struct hp3500_write_info
{
  struct hp3500_data *scanner;
  int bytesleft;
};
typedef struct detailed_calibration_data
{
  unsigned char const *channeldata[3];
  unsigned resolution_divisor;
} detailed_calibration_data;
static struct hp3500_data *first_dev = 0;
static struct hp3500_data **new_dev = &first_dev;
static int num_devices = 0;
static SANE_Int res_list[] =
  { 9, 50, 75, 100, 150, 200, 300, 400, 600, 1200 };
static const SANE_Range range_x =
  { 0, SANE_FIX (215.9), SANE_FIX (MM_PER_INCH / 1200) };
static const SANE_Range range_y =
  { 0, SANE_FIX (298.7), SANE_FIX (MM_PER_INCH / 1200) };
static const SANE_Range range_brightness =
  { 0, 255, 0 };
static const SANE_Range range_contrast =
  { 0, 255, 0 };
static const SANE_Range range_gamma =
  { SANE_FIX (0.2), SANE_FIX(4.0), SANE_FIX(0.01) };
#define HP3500_COLOR_SCAN 0
#define HP3500_GRAY_SCAN 1
#define	HP3500_LINEART_SCAN 2
#define HP3500_TOTAL_SCANS 3
static char const *scan_mode_list[HP3500_TOTAL_SCANS + 1] = { 0 };
static SANE_Status attachScanner (const char *name);
static SANE_Status init_options (struct hp3500_data *scanner);
static int reader_process (void *);
static void calculateDerivedValues (struct hp3500_data *scanner);
static void do_reset (struct hp3500_data *scanner);
static void do_cancel (struct hp3500_data *scanner);
static size_t max_string_size(char const **);
/*
 * used by sane_get_devices
 */
static const SANE_Device **devlist = 0;
/*
 * SANE Interface
 */
/**
 * Called by SANE initially.
 *
 * From the SANE spec:
 * This function must be called before any other SANE function can be
 * called. The behavior of a SANE backend is undefined if this
 * function is not called first. The version code of the backend is
 * returned in the value pointed to by version_code. If that pointer
 * is NULL, no version code is returned. Argument authorize is either
 * a pointer to a function that is invoked when the backend requires
 * authentication for a specific resource or NULL if the frontend does
 * not support authentication.
 */
SANE_Status
sane_init (SANE_Int * version_code, SANE_Auth_Callback authorize)
{
  authorize = authorize;	/* get rid of compiler warning */
  DBG_INIT ();
  DBG (10, "sane_init\n");
  sanei_usb_init ();
  sanei_thread_init ();
  if (version_code)
    *version_code = SANE_VERSION_CODE (SANE_CURRENT_MAJOR, V_MINOR, 0);
  sanei_usb_find_devices (0x03f0, 0x2205, attachScanner);
  sanei_usb_find_devices (0x03f0, 0x2005, attachScanner);
  return SANE_STATUS_GOOD;
}
/**
 * Called by SANE to find out about supported devices.
 *
 * From the SANE spec:
 * This function can be used to query the list of devices that are
 * available. If the function executes successfully, it stores a
 * pointer to a NULL terminated array of pointers to SANE_Device
 * structures in *device_list. The returned list is guaranteed to
 * remain unchanged and valid until (a) another call to this function
 * is performed or (b) a call to sane_exit() is performed. This
 * function can be called repeatedly to detect when new devices become
 * available. If argument local_only is true, only local devices are
 * returned (devices directly attached to the machine that SANE is
 * running on). If it is false, the device list includes all remote
 * devices that are accessible to the SANE library.
 *
 * SANE does not require that this function is called before a
 * sane_open() call is performed. A device name may be specified
 * explicitly by a user which would make it unnecessary and
 * undesirable to call this function first.
 */
SANE_Status
sane_get_devices (const SANE_Device *** device_list, SANE_Bool local_only)
{
  int i;
  struct hp3500_data *dev;
  DBG (10, "sane_get_devices %d\n", local_only);
  if (devlist)
    free (devlist);
  devlist = calloc (num_devices + 1, sizeof (SANE_Device *));
  if (!devlist)
    return SANE_STATUS_NO_MEM;
  for (dev = first_dev, i = 0; i < num_devices; dev = dev->next)
    devlist[i++] = &dev->sane;
  devlist[i++] = 0;
  *device_list = devlist;
  return SANE_STATUS_GOOD;
}
/**
 * Called to establish connection with the scanner. This function will
 * also establish meaningful defaults and initialize the options.
 *
 * From the SANE spec:
 * This function is used to establish a connection to a particular
 * device. The name of the device to be opened is passed in argument
 * name. If the call completes successfully, a handle for the device
 * is returned in *h. As a special case, specifying a zero-length
 * string as the device requests opening the first available device
 * (if there is such a device).
 */
SANE_Status
sane_open (SANE_String_Const name, SANE_Handle * handle)
{
  struct hp3500_data *dev = NULL;
  struct hp3500_data *scanner = NULL;
  if (name[0] == 0)
    {
      DBG (10, "sane_open: no device requested, using default\n");
      if (first_dev)
	{
	  scanner = (struct hp3500_data *) first_dev;
	  DBG (10, "sane_open: device %s found\n", first_dev->sane.name);
	}
    }
  else
    {
      DBG (10, "sane_open: device %s requested\n", name);
      for (dev = first_dev; dev; dev = dev->next)
	{
	  if (strcmp (dev->sane.name, name) == 0)
	    {
	      DBG (10, "sane_open: device %s found\n", name);
	      scanner = (struct hp3500_data *) dev;
	    }
	}
    }
  if (!scanner)
    {
      DBG (10, "sane_open: no device found\n");
      return SANE_STATUS_INVAL;
    }
  *handle = scanner;
  init_options (scanner);
  scanner->resolution = 200;
  scanner->request_mm.left = 0;
  scanner->request_mm.top = 0;
  scanner->request_mm.right = SCANNER_UNIT_TO_FIXED_MM (10200);
  scanner->request_mm.bottom = SCANNER_UNIT_TO_FIXED_MM (14100);
  scanner->mode = 0;
  scanner->brightness = 128;
  scanner->contrast = 64;
  scanner->gamma = 2.2;
  calculateDerivedValues (scanner);
  return SANE_STATUS_GOOD;
}
/**
 * An advanced method we don't support but have to define.
 */
SANE_Status
sane_set_io_mode (SANE_Handle h, SANE_Bool non_blocking)
{
  DBG (10, "sane_set_io_mode\n");
  DBG (99, "%d %p\n", non_blocking, h);
  return SANE_STATUS_UNSUPPORTED;
}
/**
 * An advanced method we don't support but have to define.
 */
SANE_Status
sane_get_select_fd (SANE_Handle h, SANE_Int * fdp)
{
  struct hp3500_data *scanner = (struct hp3500_data *) h;
  DBG (10, "sane_get_select_fd\n");
  *fdp = scanner->pipe_r;
  DBG (99, "%p %d\n", h, *fdp);
  return SANE_STATUS_GOOD;
}
/**
 * Returns the options we know.
 *
 * From the SANE spec:
 * This function is used to access option descriptors. The function
 * returns the option descriptor for option number n of the device
 * represented by handle h. Option number 0 is guaranteed to be a
 * valid option. Its value is an integer that specifies the number of
 * options that are available for device handle h (the count includes
 * option 0). If n is not a valid option index, the function returns
 * NULL. The returned option descriptor is guaranteed to remain valid
 * (and at the returned address) until the device is closed.
 */
const SANE_Option_Descriptor *
sane_get_option_descriptor (SANE_Handle handle, SANE_Int option)
{
  struct hp3500_data *scanner = handle;
  DBG (MSG_GET,
       "sane_get_option_descriptor: \"%s\"\n", scanner->opt[option].name);
  if ((unsigned) option >= NUM_OPTIONS)
    return NULL;
  return &scanner->opt[option];
}
/**
 * Gets or sets an option value.
 *
 * From the SANE spec:
 * This function is used to set or inquire the current value of option
 * number n of the device represented by handle h. The manner in which
 * the option is controlled is specified by parameter action. The
 * possible values of this parameter are described in more detail
 * below.  The value of the option is passed through argument val. It
 * is a pointer to the memory that holds the option value. The memory
 * area pointed to by v must be big enough to hold the entire option
 * value (determined by member size in the corresponding option
 * descriptor).
 *
 * The only exception to this rule is that when setting the value of a
 * string option, the string pointed to by argument v may be shorter
 * since the backend will stop reading the option value upon
 * encountering the first NUL terminator in the string. If argument i
 * is not NULL, the value of *i will be set to provide details on how
 * well the request has been met.
 */
SANE_Status
sane_control_option (SANE_Handle handle, SANE_Int option,
		     SANE_Action action, void *val, SANE_Int * info)
{
  struct hp3500_data *scanner = (struct hp3500_data *) handle;
  SANE_Status status;
  SANE_Word cap;
  SANE_Int dummy;
  int i;
  /* Make sure that all those statements involving *info cannot break (better
   * than having to do "if (info) ..." everywhere!)
   */
  if (info == 0)
    info = &dummy;
  *info = 0;
  if (option >= NUM_OPTIONS)
    return SANE_STATUS_INVAL;
  cap = scanner->opt[option].cap;
  /*
   * SANE_ACTION_GET_VALUE: We have to find out the current setting and
   * return it in a human-readable form (often, text).
   */
  if (action == SANE_ACTION_GET_VALUE)
    {
      DBG (MSG_GET, "sane_control_option: get value \"%s\"\n",
	   scanner->opt[option].name);
      DBG (11, "\tcap = %d\n", cap);
      if (!SANE_OPTION_IS_ACTIVE (cap))
	{
	  DBG (10, "\tinactive\n");
	  return SANE_STATUS_INVAL;
	}
      switch (option)
	{
	case OPT_NUM_OPTS:
	  *(SANE_Word *) val = NUM_OPTIONS;
	  return SANE_STATUS_GOOD;
	case OPT_RESOLUTION:
	  *(SANE_Word *) val = scanner->resolution;
	  return SANE_STATUS_GOOD;
	case OPT_TL_X:
	  *(SANE_Word *) val = scanner->request_mm.left;
	  return SANE_STATUS_GOOD;
	case OPT_TL_Y:
	  *(SANE_Word *) val = scanner->request_mm.top;
	  return SANE_STATUS_GOOD;
	case OPT_BR_X:
	  *(SANE_Word *) val = scanner->request_mm.right;
	  return SANE_STATUS_GOOD;
	case OPT_BR_Y:
	  *(SANE_Word *) val = scanner->request_mm.bottom;
	  return SANE_STATUS_GOOD;
	case OPT_MODE:
	  strcpy ((SANE_Char *) val, scan_mode_list[scanner->mode]);
	  return SANE_STATUS_GOOD;
	case OPT_CONTRAST:
	  *(SANE_Word *) val = scanner->contrast;
	  return SANE_STATUS_GOOD;
        case OPT_GAMMA:
          *(SANE_Word *) val = SANE_FIX(scanner->gamma);
	  return SANE_STATUS_GOOD;
	case OPT_BRIGHTNESS:
	  *(SANE_Word *) val = scanner->brightness;
	  return SANE_STATUS_GOOD;
	}
    }
  else if (action == SANE_ACTION_SET_VALUE)
    {
      DBG (10, "sane_control_option: set value \"%s\"\n",
	   scanner->opt[option].name);
      if (!SANE_OPTION_IS_ACTIVE (cap))
	{
	  DBG (10, "\tinactive\n");
	  return SANE_STATUS_INVAL;
	}
      if (!SANE_OPTION_IS_SETTABLE (cap))
	{
	  DBG (10, "\tnot settable\n");
	  return SANE_STATUS_INVAL;
	}
      status = sanei_constrain_value (scanner->opt + option, val, info);
      if (status != SANE_STATUS_GOOD)
	{
	  DBG (10, "\tbad value\n");
	  return status;
	}
      /*
       * Note - for those options which can assume one of a list of
       * valid values, we can safely assume that they will have
       * exactly one of those values because that's what
       * sanei_constrain_value does. Hence no "else: invalid" branches
       * below.
       */
      switch (option)
	{
	case OPT_RESOLUTION:
	  if (scanner->resolution == *(SANE_Word *) val)
	    {
	      return SANE_STATUS_GOOD;
	    }
	  scanner->resolution = (*(SANE_Word *) val);
	  calculateDerivedValues (scanner);
	  *info |= SANE_INFO_RELOAD_PARAMS;
	  return SANE_STATUS_GOOD;
	case OPT_TL_X:
	  if (scanner->request_mm.left == *(SANE_Word *) val)
	    return SANE_STATUS_GOOD;
	  scanner->request_mm.left = *(SANE_Word *) val;
	  calculateDerivedValues (scanner);
	  if (scanner->actual_mm.left != scanner->request_mm.left)
	    *info |= SANE_INFO_INEXACT;
	  *info |= SANE_INFO_RELOAD_PARAMS;
	  return SANE_STATUS_GOOD;
	case OPT_TL_Y:
	  if (scanner->request_mm.top == *(SANE_Word *) val)
	    return SANE_STATUS_GOOD;
	  scanner->request_mm.top = *(SANE_Word *) val;
	  calculateDerivedValues (scanner);
	  if (scanner->actual_mm.top != scanner->request_mm.top)
	    *info |= SANE_INFO_INEXACT;
	  *info |= SANE_INFO_RELOAD_PARAMS;
	  return SANE_STATUS_GOOD;
	case OPT_BR_X:
	  if (scanner->request_mm.right == *(SANE_Word *) val)
	    {
	      return SANE_STATUS_GOOD;
	    }
	  scanner->request_mm.right = *(SANE_Word *) val;
	  calculateDerivedValues (scanner);
	  if (scanner->actual_mm.right != scanner->request_mm.right)
	    *info |= SANE_INFO_INEXACT;
	  *info |= SANE_INFO_RELOAD_PARAMS;
	  return SANE_STATUS_GOOD;
	case OPT_BR_Y:
	  if (scanner->request_mm.bottom == *(SANE_Word *) val)
	    {
	      return SANE_STATUS_GOOD;
	    }
	  scanner->request_mm.bottom = *(SANE_Word *) val;
	  calculateDerivedValues (scanner);
	  if (scanner->actual_mm.bottom != scanner->request_mm.bottom)
	    *info |= SANE_INFO_INEXACT;
	  *info |= SANE_INFO_RELOAD_PARAMS;
	  return SANE_STATUS_GOOD;
	case OPT_MODE:
	  for (i = 0; scan_mode_list[i]; ++i)
	    {
	      if (!strcmp ((SANE_Char const *) val, scan_mode_list[i]))
		{
		  DBG (10, "Setting scan mode to %s (request: %s)\n",
		       scan_mode_list[i], (SANE_Char const *) val);
		  scanner->mode = i;
		  return SANE_STATUS_GOOD;
		}
	    }
	  /* Impossible */
	  return SANE_STATUS_INVAL;
	case OPT_BRIGHTNESS:
	  scanner->brightness = *(SANE_Word *) val;
	  return SANE_STATUS_GOOD;
	case OPT_CONTRAST:
	  scanner->contrast = *(SANE_Word *) val;
	  return SANE_STATUS_GOOD;
        case OPT_GAMMA:
          scanner->gamma = SANE_UNFIX(*(SANE_Word *) val);
          return SANE_STATUS_GOOD;
	}			/* switch */
    }				/* else */
  return SANE_STATUS_INVAL;
}
/**
 * Called by SANE when a page acquisition operation is to be started.
 *
 */
SANE_Status
sane_start (SANE_Handle handle)
{
  struct hp3500_data *scanner = handle;
  int defaultFds[2];
  int ret;
  DBG (10, "sane_start\n");
  if (scanner->sfd < 0)
    {
      /* first call */
      DBG (10, "sane_start opening USB device\n");
      if (sanei_usb_open (scanner->sane.name, &(scanner->sfd)) !=
	  SANE_STATUS_GOOD)
	{
	  DBG (MSG_ERR,
	       "sane_start: open of %s failed:\n", scanner->sane.name);
	  return SANE_STATUS_INVAL;
	}
    }
  calculateDerivedValues (scanner);
  DBG (10, "\tbytes per line = %d\n", scanner->bytes_per_scan_line);
  DBG (10, "\tpixels_per_line = %d\n", scanner->scan_width_pixels);
  DBG (10, "\tlines = %d\n", scanner->scan_height_pixels);
  /* create a pipe, fds[0]=read-fd, fds[1]=write-fd */
  if (pipe (defaultFds) < 0)
    {
      DBG (MSG_ERR, "ERROR: could not create pipe\n");
      do_cancel (scanner);
      return SANE_STATUS_IO_ERROR;
    }
  scanner->pipe_r = defaultFds[0];
  scanner->pipe_w = defaultFds[1];
  ret = SANE_STATUS_GOOD;
  scanner->reader_pid = sanei_thread_begin (reader_process, scanner);
  time (&scanner->last_scan);
  if (!sanei_thread_is_valid (scanner->reader_pid))
    {
      DBG (MSG_ERR, "cannot fork reader process.\n");
      DBG (MSG_ERR, "%s", strerror (errno));
      ret = SANE_STATUS_IO_ERROR;
    }
  if (sanei_thread_is_forked ())
    {
      close (scanner->pipe_w);
    }
  if (ret == SANE_STATUS_GOOD)
    {
      DBG (10, "sane_start: ok\n");
    }
  return ret;
}
/**
 * Called by SANE to retrieve information about the type of data
 * that the current scan will return.
 *
 * From the SANE spec:
 * This function is used to obtain the current scan parameters. The
 * returned parameters are guaranteed to be accurate between the time
 * a scan has been started (sane_start() has been called) and the
 * completion of that request. Outside of that window, the returned
 * values are best-effort estimates of what the parameters will be
 * when sane_start() gets invoked.
 *
 * Calling this function before a scan has actually started allows,
 * for example, to get an estimate of how big the scanned image will
 * be. The parameters passed to this function are the handle h of the
 * device for which the parameters should be obtained and a pointer p
 * to a parameter structure.
 */
SANE_Status
sane_get_parameters (SANE_Handle handle, SANE_Parameters * params)
{
  struct hp3500_data *scanner = (struct hp3500_data *) handle;
  DBG (10, "sane_get_parameters\n");
  calculateDerivedValues (scanner);
  params->format =
    (scanner->mode == HP3500_COLOR_SCAN) ? SANE_FRAME_RGB : SANE_FRAME_GRAY;
  params->depth = (scanner->mode == HP3500_LINEART_SCAN) ? 1 : 8;
  params->pixels_per_line = scanner->scan_width_pixels;
  params->lines = scanner->scan_height_pixels;
  params->bytes_per_line = scanner->bytes_per_scan_line;
  params->last_frame = 1;
  DBG (10, "\tdepth %d\n", params->depth);
  DBG (10, "\tlines %d\n", params->lines);
  DBG (10, "\tpixels_per_line %d\n", params->pixels_per_line);
  DBG (10, "\tbytes_per_line %d\n", params->bytes_per_line);
  return SANE_STATUS_GOOD;
}
/**
 * Called by SANE to read data.
 *
 * In this implementation, sane_read does nothing much besides reading
 * data from a pipe and handing it back. On the other end of the pipe
 * there's the reader process which gets data from the scanner and
 * stuffs it into the pipe.
 *
 * From the SANE spec:
 * This function is used to read image data from the device
 * represented by handle h.  Argument buf is a pointer to a memory
 * area that is at least maxlen bytes long.  The number of bytes
 * returned is stored in *len. A backend must set this to zero when
 * the call fails (i.e., when a status other than SANE_STATUS_GOOD is
 * returned).
 *
 * When the call succeeds, the number of bytes returned can be
 * anywhere in the range from 0 to maxlen bytes.
 */
SANE_Status
sane_read (SANE_Handle handle, SANE_Byte * buf,
	   SANE_Int max_len, SANE_Int * len)
{
  struct hp3500_data *scanner = (struct hp3500_data *) handle;
  ssize_t nread;
  int source = scanner->pipe_r;
  *len = 0;
  nread = read (source, buf, max_len);
  DBG (30, "sane_read: read %ld bytes of %ld\n",
       (long) nread, (long) max_len);
  if (nread < 0)
    {
      if (errno == EAGAIN)
	{
	  return SANE_STATUS_GOOD;
	}
      else
	{
	  do_cancel (scanner);
	  return SANE_STATUS_IO_ERROR;
	}
    }
  *len = nread;
  if (nread == 0)
    {
      close (source);
      DBG (10, "sane_read: pipe closed\n");
      return SANE_STATUS_EOF;
    }
  return SANE_STATUS_GOOD;
}				/* sane_read */
/**
 * Cancels a scan.
 *
 * It has been said on the mailing list that sane_cancel is a bit of a
 * misnomer because it is routinely called to signal the end of a
 * batch - quoting David Mosberger-Tang:
 *
 * > In other words, the idea is to have sane_start() be called, and
 * > collect as many images as the frontend wants (which could in turn
 * > consist of multiple frames each as indicated by frame-type) and
 * > when the frontend is done, it should call sane_cancel().
 * > Sometimes it's better to think of sane_cancel() as "sane_stop()"
 * > but that name would have had some misleading connotations as
 * > well, that's why we stuck with "cancel".
 *
 * The current consensus regarding duplex and ADF scans seems to be
 * the following call sequence: sane_start; sane_read (repeat until
 * EOF); sane_start; sane_read...  and then call sane_cancel if the
 * batch is at an end. I.e. do not call sane_cancel during the run but
 * as soon as you get a SANE_STATUS_NO_DOCS.
 *
 * From the SANE spec:
 * This function is used to immediately or as quickly as possible
 * cancel the currently pending operation of the device represented by
 * handle h.  This function can be called at any time (as long as
 * handle h is a valid handle) but usually affects long-running
 * operations only (such as image is acquisition). It is safe to call
 * this function asynchronously (e.g., from within a signal handler).
 * It is important to note that completion of this operation does not
 * imply that the currently pending operation has been cancelled. It
 * only guarantees that cancellation has been initiated. Cancellation
 * completes only when the cancelled call returns (typically with a
 * status value of SANE_STATUS_CANCELLED).  Since the SANE API does
 * not require any other operations to be re-entrant, this implies
 * that a frontend must not call any other operation until the
 * cancelled operation has returned.
 */
void
sane_cancel (SANE_Handle h)
{
  DBG (10, "sane_cancel\n");
  do_cancel ((struct hp3500_data *) h);
}
/**
 * Ends use of the scanner.
 *
 * From the SANE spec:
 * This function terminates the association between the device handle
 * passed in argument h and the device it represents. If the device is
 * presently active, a call to sane_cancel() is performed first. After
 * this function returns, handle h must not be used anymore.
 */
void
sane_close (SANE_Handle handle)
{
  DBG (10, "sane_close\n");
  do_reset (handle);
  do_cancel (handle);
}
/**
 * Terminates the backend.
 *
 * From the SANE spec:
 * This function must be called to terminate use of a backend. The
 * function will first close all device handles that still might be
 * open (it is recommended to close device handles explicitly through
 * a call to sane_clo-se(), but backends are required to release all
 * resources upon a call to this function). After this function
 * returns, no function other than sane_init() may be called
 * (regardless of the status value returned by sane_exit(). Neglecting
 * to call this function may result in some resources not being
 * released properly.
 */
void
sane_exit (void)
{
  struct hp3500_data *dev, *next;
  DBG (10, "sane_exit\n");
  for (dev = first_dev; dev; dev = next)
    {
      next = dev->next;
      free (dev->devicename);
      free (dev);
    }
  if (devlist)
    free (devlist);
}
/*
 * The scanning code
 */
static SANE_Status
attachScanner (const char *devicename)
{
  struct hp3500_data *dev;
  DBG (15, "attach_scanner: %s\n", devicename);
  for (dev = first_dev; dev; dev = dev->next)
    {
      if (strcmp (dev->sane.name, devicename) == 0)
	{
	  DBG (5, "attach_scanner: scanner already attached (is ok)!\n");
	  return SANE_STATUS_GOOD;
	}
    }
  if (NULL == (dev = malloc (sizeof (*dev))))
    return SANE_STATUS_NO_MEM;
  memset (dev, 0, sizeof (*dev));
  dev->devicename = strdup (devicename);
  dev->sfd = -1;
  dev->last_scan = 0;
  dev->reader_pid = (SANE_Pid) -1;
  dev->pipe_r = dev->pipe_w = -1;
  dev->sane.name = dev->devicename;
  dev->sane.vendor = "Hewlett-Packard";
  dev->sane.model = "ScanJet 3500";
  dev->sane.type = "scanner";
  ++num_devices;
  *new_dev = dev;
  DBG (15, "attach_scanner: done\n");
  return SANE_STATUS_GOOD;
}
static SANE_Status
init_options (struct hp3500_data *scanner)
{
  int i;
  SANE_Option_Descriptor *opt;
  memset (scanner->opt, 0, sizeof (scanner->opt));
  for (i = 0; i < NUM_OPTIONS; ++i)
    {
      scanner->opt[i].name = "filler";
      scanner->opt[i].size = sizeof (SANE_Word);
      scanner->opt[i].cap = SANE_CAP_INACTIVE;
    }
  opt = scanner->opt + OPT_NUM_OPTS;
  opt->title = SANE_TITLE_NUM_OPTIONS;
  opt->desc = SANE_DESC_NUM_OPTIONS;
  opt->type = SANE_TYPE_INT;
  opt->cap = SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_RESOLUTION;
  opt->name = SANE_NAME_SCAN_RESOLUTION;
  opt->title = SANE_TITLE_SCAN_RESOLUTION;
  opt->desc = SANE_DESC_SCAN_RESOLUTION;
  opt->type = SANE_TYPE_INT;
  opt->constraint_type = SANE_CONSTRAINT_WORD_LIST;
  opt->constraint.word_list = res_list;
  opt->unit = SANE_UNIT_DPI;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_GEOMETRY_GROUP;
  opt->title = SANE_I18N ("Geometry");
  opt->desc = SANE_I18N ("Geometry Group");
  opt->type = SANE_TYPE_GROUP;
  opt->constraint_type = SANE_CONSTRAINT_NONE;
  opt = scanner->opt + OPT_TL_X;
  opt->name = SANE_NAME_SCAN_TL_X;
  opt->title = SANE_TITLE_SCAN_TL_X;
  opt->desc = SANE_DESC_SCAN_TL_X;
  opt->type = SANE_TYPE_FIXED;
  opt->unit = SANE_UNIT_MM;
  opt->constraint_type = SANE_CONSTRAINT_RANGE;
  opt->constraint.range = &range_x;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_TL_Y;
  opt->name = SANE_NAME_SCAN_TL_Y;
  opt->title = SANE_TITLE_SCAN_TL_Y;
  opt->desc = SANE_DESC_SCAN_TL_Y;
  opt->type = SANE_TYPE_FIXED;
  opt->unit = SANE_UNIT_MM;
  opt->constraint_type = SANE_CONSTRAINT_RANGE;
  opt->constraint.range = &range_y;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_BR_X;
  opt->name = SANE_NAME_SCAN_BR_X;
  opt->title = SANE_TITLE_SCAN_BR_X;
  opt->desc = SANE_DESC_SCAN_BR_X;
  opt->type = SANE_TYPE_FIXED;
  opt->unit = SANE_UNIT_MM;
  opt->constraint_type = SANE_CONSTRAINT_RANGE;
  opt->constraint.range = &range_x;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_BR_Y;
  opt->name = SANE_NAME_SCAN_BR_Y;
  opt->title = SANE_TITLE_SCAN_BR_Y;
  opt->desc = SANE_DESC_SCAN_BR_Y;
  opt->type = SANE_TYPE_FIXED;
  opt->unit = SANE_UNIT_MM;
  opt->constraint_type = SANE_CONSTRAINT_RANGE;
  opt->constraint.range = &range_y;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  if (!scan_mode_list[0])
    {
      scan_mode_list[HP3500_COLOR_SCAN] = SANE_VALUE_SCAN_MODE_COLOR;
      scan_mode_list[HP3500_GRAY_SCAN] = SANE_VALUE_SCAN_MODE_GRAY;
      scan_mode_list[HP3500_LINEART_SCAN] = SANE_VALUE_SCAN_MODE_LINEART;
      scan_mode_list[HP3500_TOTAL_SCANS] = 0;
    }
  opt = scanner->opt + OPT_MODE_GROUP;
  opt->title = SANE_I18N ("Scan Mode Group");
  opt->desc = SANE_I18N ("Scan Mode Group");
  opt->type = SANE_TYPE_GROUP;
  opt->constraint_type = SANE_CONSTRAINT_NONE;
  opt = scanner->opt + OPT_MODE;
  opt->name = SANE_NAME_SCAN_MODE;
  opt->title = SANE_TITLE_SCAN_MODE;
  opt->desc = SANE_DESC_SCAN_MODE;
  opt->type = SANE_TYPE_STRING;
  opt->size = max_string_size(scan_mode_list);
  opt->constraint_type = SANE_CONSTRAINT_STRING_LIST;
  opt->constraint.string_list = (SANE_String_Const *) scan_mode_list;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_BRIGHTNESS;
  opt->name = SANE_NAME_BRIGHTNESS;
  opt->title = SANE_TITLE_BRIGHTNESS;
  opt->desc = SANE_DESC_BRIGHTNESS;
  opt->type = SANE_TYPE_INT;
  opt->constraint_type = SANE_CONSTRAINT_RANGE;
  opt->constraint.range = &range_brightness;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_CONTRAST;
  opt->name = SANE_NAME_CONTRAST;
  opt->title = SANE_TITLE_CONTRAST;
  opt->desc = SANE_DESC_CONTRAST;
  opt->type = SANE_TYPE_INT;
  opt->constraint_type = SANE_CONSTRAINT_RANGE;
  opt->constraint.range = &range_contrast;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  opt = scanner->opt + OPT_GAMMA;
  opt->name = SANE_NAME_ANALOG_GAMMA;
  opt->title = SANE_TITLE_ANALOG_GAMMA;
  opt->desc = SANE_DESC_ANALOG_GAMMA;
  opt->type = SANE_TYPE_FIXED;
  opt->unit = SANE_UNIT_NONE;
  opt->constraint_type = SANE_CONSTRAINT_RANGE;
  opt->constraint.range = &range_gamma;
  opt->cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
  return SANE_STATUS_GOOD;
}
static void
do_reset (struct hp3500_data *scanner)
{
  scanner = scanner;		/* kill warning */
}
static void
do_cancel (struct hp3500_data *scanner)
{
  if (sanei_thread_is_valid (scanner->reader_pid))
    {
      if (sanei_thread_kill (scanner->reader_pid) == 0)
	{
	  int exit_status;
	  sanei_thread_waitpid (scanner->reader_pid, &exit_status);
	}
      sanei_thread_invalidate (scanner->reader_pid);
    }
  if (scanner->pipe_r >= 0)
    {
      close (scanner->pipe_r);
      scanner->pipe_r = -1;
    }
}
static void
calculateDerivedValues (struct hp3500_data *scanner)
{
  DBG (12, "calculateDerivedValues\n");
  /* Convert the SANE_FIXED values for the scan area into 1/1200 inch
   * scanner units */
  scanner->fullres_pixels.left =
    FIXED_MM_TO_SCANNER_UNIT (scanner->request_mm.left);
  scanner->fullres_pixels.top =
    FIXED_MM_TO_SCANNER_UNIT (scanner->request_mm.top);
  scanner->fullres_pixels.right =
    FIXED_MM_TO_SCANNER_UNIT (scanner->request_mm.right);
  scanner->fullres_pixels.bottom =
    FIXED_MM_TO_SCANNER_UNIT (scanner->request_mm.bottom);
  DBG (12, "\tleft margin: %u\n", scanner->fullres_pixels.left);
  DBG (12, "\ttop margin: %u\n", scanner->fullres_pixels.top);
  DBG (12, "\tright margin: %u\n", scanner->fullres_pixels.right);
  DBG (12, "\tbottom margin: %u\n", scanner->fullres_pixels.bottom);
  scanner->scan_width_pixels =
    scanner->resolution * (scanner->fullres_pixels.right -
			   scanner->fullres_pixels.left) / 1200;
  scanner->scan_height_pixels =
    scanner->resolution * (scanner->fullres_pixels.bottom -
			   scanner->fullres_pixels.top) / 1200;
  if (scanner->mode == HP3500_LINEART_SCAN)
    scanner->bytes_per_scan_line = (scanner->scan_width_pixels + 7) / 8;
  else if (scanner->mode == HP3500_GRAY_SCAN)
    scanner->bytes_per_scan_line = scanner->scan_width_pixels;
  else
    scanner->bytes_per_scan_line = scanner->scan_width_pixels * 3;
  if (scanner->scan_width_pixels < 1)
    scanner->scan_width_pixels = 1;
  if (scanner->scan_height_pixels < 1)
    scanner->scan_height_pixels = 1;
  scanner->actres_pixels.left =
    scanner->fullres_pixels.left * scanner->resolution / 1200;
  scanner->actres_pixels.top =
    scanner->fullres_pixels.top * scanner->resolution / 1200;
  scanner->actres_pixels.right =
    scanner->actres_pixels.left + scanner->scan_width_pixels;
  scanner->actres_pixels.bottom =
    scanner->actres_pixels.top + scanner->scan_height_pixels;
  scanner->actual_mm.left =
    SCANNER_UNIT_TO_FIXED_MM (scanner->fullres_pixels.left);
  scanner->actual_mm.top =
    SCANNER_UNIT_TO_FIXED_MM (scanner->fullres_pixels.top);
  scanner->actual_mm.bottom =
    SCANNER_UNIT_TO_FIXED_MM (scanner->scan_width_pixels * 1200 /
			      scanner->resolution);
  scanner->actual_mm.right =
    SCANNER_UNIT_TO_FIXED_MM (scanner->scan_height_pixels * 1200 /
			      scanner->resolution);
  DBG (12, "calculateDerivedValues: ok\n");
}
/* From here on in we have the original code written for the scanner demo */
#define	MAX_COMMANDS_BYTES	131072
#define	MAX_READ_COMMANDS	1	/* Issuing more than one register
					 * read command in a single request
					 * seems to put the device in an
					 * unpredictable state.
					 */
#define	MAX_READ_BYTES		0xffc0
#define	REG_DESTINATION_POSITION 0x60
#define	REG_MOVE_CONTROL_TEST	0xb3
static int command_reads_outstanding = 0;
static int command_bytes_outstanding = 0;
static unsigned char command_buffer[MAX_COMMANDS_BYTES];
static int receive_bytes_outstanding = 0;
static char *command_readmem_outstanding[MAX_READ_COMMANDS];
static int command_readbytes_outstanding[MAX_READ_COMMANDS];
static unsigned char sram_access_method = 0;
static unsigned sram_size = 0;
static int udh;
static int
rt_execute_commands (void)
{
  SANE_Status result;
  size_t bytes;
  if (!command_bytes_outstanding)
    return 0;
  bytes = command_bytes_outstanding;
  result = sanei_usb_write_bulk (udh, /* 0x02, */ command_buffer, &bytes);
  if (result == SANE_STATUS_GOOD && receive_bytes_outstanding)
    {
      unsigned char readbuf[MAX_READ_BYTES];
      int total_read = 0;
      do
	{
	  bytes = receive_bytes_outstanding - total_read;
	  result = sanei_usb_read_bulk (udh,
					/* 0x81, */
					readbuf + total_read, &bytes);
	  if (result == SANE_STATUS_GOOD)
	    total_read += bytes;
	  else
	    break;
	}
      while (total_read < receive_bytes_outstanding);
      if (result == SANE_STATUS_GOOD)
	{
	  unsigned char *readptr;
	  int i;
	  for (i = 0, readptr = readbuf;
	       i < command_reads_outstanding;
	       readptr += command_readbytes_outstanding[i++])
	    {
	      memcpy (command_readmem_outstanding[i],
		      readptr, command_readbytes_outstanding[i]);
	    }
	}
    }
  receive_bytes_outstanding = command_reads_outstanding =
    command_bytes_outstanding = 0;
  return (result == SANE_STATUS_GOOD) ? 0 : -1;
}
static int
rt_queue_command (int command,
		  int reg,
		  int count,
		  int bytes, void const *data_, int readbytes, void *readdata)
{
  int len = 4 + bytes;
  unsigned char *buffer;
  unsigned char const *data = data_;
  /* We add "bytes" here to account for the possibility that all of the
   * data bytes are 0xaa and hence require a following 0x00 byte.
   */
  if (command_bytes_outstanding + len + bytes > MAX_COMMANDS_BYTES ||
      (readbytes &&
       ((command_reads_outstanding >= MAX_READ_COMMANDS) ||
	(receive_bytes_outstanding >= MAX_READ_BYTES))))
    {
      if (rt_execute_commands () < 0)
	return -1;
    }
  buffer = command_buffer + command_bytes_outstanding;
  *buffer++ = command;
  *buffer++ = reg;
  *buffer++ = count >> 8;
  *buffer++ = count;
  while (bytes--)
    {
      *buffer++ = *data;
      if (*data++ == 0xaa)
	{
	  *buffer++ = 0;
	  ++len;
	}
    }
  command_bytes_outstanding += len;
  if (readbytes)
    {
      command_readbytes_outstanding[command_reads_outstanding] = readbytes;
      command_readmem_outstanding[command_reads_outstanding] = readdata;
      receive_bytes_outstanding += readbytes;
      ++command_reads_outstanding;
    }
  return 0;
}
static int
rt_send_command_immediate (int command,
			   int reg,
			   int count,
			   int bytes,
			   void *data, int readbytes, void *readdata)
{
  rt_queue_command (command, reg, count, bytes, data, readbytes, readdata);
  return rt_execute_commands ();
}
static int
rt_queue_read_register (int reg, int bytes, void *data)
{
  return rt_queue_command (RTCMD_GETREG, reg, bytes, 0, 0, bytes, data);
}
static int
rt_read_register_immediate (int reg, int bytes, void *data)
{
  if (rt_queue_read_register (reg, bytes, data) < 0)
    return -1;
  return rt_execute_commands ();
}
static int
rt_queue_set_register (int reg, int bytes, void *data)
{
  return rt_queue_command (RTCMD_SETREG, reg, bytes, bytes, data, 0, 0);
}
static int
rt_set_register_immediate (int reg, int bytes, void *data)
{
  if (reg < 0xb3 && reg + bytes > 0xb3)
    {
      int bytes_in_first_block = 0xb3 - reg;
      if (rt_set_register_immediate (reg, bytes_in_first_block, data) < 0 ||
	  rt_set_register_immediate (0xb4, bytes - bytes_in_first_block - 1,
				     (char *) data + bytes_in_first_block +
				     1) < 0)
	return -1;
      return 0;
    }
  if (rt_queue_set_register (reg, bytes, data) < 0)
    return -1;
  return rt_execute_commands ();
}
static int
rt_set_one_register (int reg, int val)
{
  char r = val;
  return rt_set_register_immediate (reg, 1, &r);
}
static int
rt_write_sram (int bytes, void *data_)
{
  unsigned char *data = (unsigned char *) data_;
  /* The number of bytes passed in could be much larger than we can transmit
   * (0xffc0) bytes. With 0xaa escapes it could be even larger. Accordingly
   * we need to count the 0xaa escapes and write in chunks if the number of
   * bytes would otherwise exceed a limit (I have used 0xf000 as the limit).
   */
  while (bytes > 0)
    {
      int now = 0;
      int bufsize = 0;
      while (now < bytes && bufsize < 0xf000)
	{
	  int i;
	  /* Try to avoid writing part pages */
	  for (i = 0; i < 32 && now < bytes; ++i)
	    {
	      ++bufsize;
	      if (data[now++] == 0xaa)
		++bufsize;
	    }
	}
      if (rt_send_command_immediate (RTCMD_WRITESRAM, 0, now, now, data, 0,
				     0) < 0)
	return -1;
      bytes -= now;
      data += now;
    }
  return 0;
}
static int
rt_read_sram (int bytes, void *data_)
{
  unsigned char *data = (unsigned char *) data_;
  while (bytes > 0)
    {
      int now = (bytes > 0xf000) ? 0xf000 : bytes;
      if (rt_send_command_immediate (RTCMD_READSRAM, 0, bytes, 0, 0, bytes,
				     data) < 0)
	return -1;
      bytes -= now;
      data += now;
    }
  return 0;
}
static int
rt_set_sram_page (int page)
{
  unsigned char regs[2];
  regs[0] = page;
  regs[1] = page >> 8;
  return rt_set_register_immediate (0x91, 2, regs);
}
static int
rt_detect_sram (unsigned *totalbytes, unsigned char *r93setting)
{
  char data[0x818];
  char testbuf[0x818];
  unsigned i;
  int test_values[] = { 6, 2, 1, -1 };
  for (i = 0; i < sizeof (data); ++i)
    data[i] = i % 0x61;
  for (i = 0; test_values[i] != -1; ++i)
    {
      if (rt_set_one_register (0x93, test_values[i]) ||
	  rt_set_sram_page (0x81) ||
	  rt_write_sram (0x818, data) ||
	  rt_set_sram_page (0x81) || rt_read_sram (0x818, testbuf))
	return -1;
      if (!memcmp (testbuf, data, 0x818))
	{
	  sram_access_method = test_values[i];
	  if (r93setting)
	    *r93setting = sram_access_method;
	  break;
	}
    }
  if (!sram_access_method)
    return -1;
  for (i = 0; i < 16; ++i)
    {
      int j;
      char write_data[32];
      char read_data[32];
      int pagesetting;
      for (j = 0; j < 16; j++)
	{
	  write_data[j * 2] = j * 2;
	  write_data[j * 2 + 1] = i;
	}
      pagesetting = i * 4096;
      if (rt_set_sram_page (pagesetting) < 0 ||
	  rt_write_sram (32, write_data) < 0)
	return -1;
      if (i)
	{
	  if (rt_set_sram_page (0) < 0 || rt_read_sram (32, read_data) < 0)
	    return -1;
	  if (!memcmp (read_data, write_data, 32))
	    {
	      sram_size = i * 0x20000;
	      if (totalbytes)
		*totalbytes = sram_size;
	      return 0;
	    }
	}
    }
  return -1;
}
static int
rt_get_available_bytes (void)
{
  unsigned char data[3];
  if (rt_queue_command (RTCMD_BYTESAVAIL, 0, 3, 0, 0, 3, data) < 0 ||
      rt_execute_commands () < 0)
    return -1;
  return ((unsigned) data[0]) |
    ((unsigned) data[1] << 8) | ((unsigned) data[2] << 16);
}
static int
rt_get_data (int bytes, void *data)
{
  int total = 0;
  while (bytes)
    {
      int bytesnow = bytes;
      if (bytesnow > 0xffc0)
	bytesnow = 0xffc0;
      if (rt_queue_command
	  (RTCMD_READBYTES, 0, bytesnow, 0, 0, bytesnow, data) < 0
	  || rt_execute_commands () < 0)
	return -1;
      total += bytesnow;
      bytes -= bytesnow;
      data = (char *) data + bytesnow;
    }
  return 0;
}
static int
rt_is_moving (void)
{
  char r;
  if (rt_read_register_immediate (REG_MOVE_CONTROL_TEST, 1, &r) < 0)
    return -1;
  if (r == 0x08)
    return 1;
  return 0;
}
static int
rt_is_rewound (void)
{
  char r;
  if (rt_read_register_immediate (0x1d, 1, &r) < 0)
    return -1;
  if (r & 0x02)
    return 1;
  return 0;
}
static int
rt_set_direction_forwards (unsigned char *regs)
{
  regs[0xc6] |= 0x08;
  return 0;
}
static int
rt_set_direction_rewind (unsigned char *regs)
{
  regs[0xc6] &= 0xf7;
  return 0;
}
static int
rt_set_stop_when_rewound (unsigned char *regs, int stop)
{
  if (stop)
    regs[0xb2] |= 0x10;
  else
    regs[0xb2] &= 0xef;
  return 0;
}
static int
rt_start_moving (void)
{
  if (rt_set_one_register (REG_MOVE_CONTROL_TEST, 2) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 2) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 0) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 0) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 8) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 8) < 0)
    return -1;
  return 0;
}
static int
rt_stop_moving (void)
{
  if (rt_set_one_register (REG_MOVE_CONTROL_TEST, 2) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 2) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 0) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, 0) < 0)
    return -1;
  return 0;
}
static int
rt_set_powersave_mode (int enable)
{
  unsigned char r;
  if (rt_read_register_immediate (REG_MOVE_CONTROL_TEST, 1, &r) < 0)
    return -1;
  if (r & 0x04)
    {
      if (enable == 1)
	return 0;
      r &= ~0x04;
    }
  else
    {
      if (enable == 0)
	return 0;
      r |= 0x04;
    }
  if (rt_set_one_register (REG_MOVE_CONTROL_TEST, r) < 0 ||
      rt_set_one_register (REG_MOVE_CONTROL_TEST, r) < 0)
    return -1;
  return 0;
}
static int
rt_turn_off_lamp (void)
{
  return rt_set_one_register (0x3a, 0);
}
static int
rt_turn_on_lamp (void)
{
  char r3ab[2];
  char r10;
  char r58;
  if (rt_read_register_immediate (0x3a, 1, r3ab) < 0 ||
      rt_read_register_immediate (0x10, 1, &r10) < 0 ||
      rt_read_register_immediate (0x58, 1, &r58) < 0)
    return -1;
  r3ab[0] |= 0x80;
  r3ab[1] = 0x40;
  r10 |= 0x01;
  r58 &= 0x0f;
  if (rt_set_register_immediate (0x3a, 2, r3ab) < 0 ||
      rt_set_one_register (0x10, r10) < 0 ||
      rt_set_one_register (0x58, r58) < 0)
    return -1;
  return 0;
}
static int
rt_set_value_lsbfirst (unsigned char *regs,
		       int firstreg, int totalregs, unsigned value)
{
  while (totalregs--)
    {
      regs[firstreg++] = value & 0xff;
      value >>= 8;
    }
  return 0;
}
#if 0
static int
rt_set_value_msbfirst (unsigned char *regs,
		       int firstreg, int totalregs, unsigned value)
{
  while (totalregs--)
    {
      regs[firstreg + totalregs] = value & 0xff;
      value >>= 8;
    }
  return 0;
}
#endif
static int
rt_set_ccd_shift_clock_multiplier (unsigned char *regs, unsigned value)
{
  return rt_set_value_lsbfirst (regs, 0xf0, 3, value);
}
static int
rt_set_ccd_clock_reset_interval (unsigned char *regs, unsigned value)
{
  return rt_set_value_lsbfirst (regs, 0xf9, 3, value);
}
static int
rt_set_ccd_clamp_clock_multiplier (unsigned char *regs, unsigned value)
{
  return rt_set_value_lsbfirst (regs, 0xfc, 3, value);
}
static int
rt_set_movement_pattern (unsigned char *regs, unsigned value)
{
  return rt_set_value_lsbfirst (regs, 0xc0, 3, value);
}
static int
rt_set_motor_movement_clock_multiplier (unsigned char *regs, unsigned value)
{
  regs[0x40] = (regs[0x40] & ~0xc0) | (value << 6);
  return 0;
}
static int
rt_set_motor_type (unsigned char *regs, unsigned value)
{
  regs[0xc9] = (regs[0xc9] & 0xf8) | (value & 0x7);
  return 0;
}
static int
rt_set_noscan_distance (unsigned char *regs, unsigned value)
{
  DBG (10, "Setting distance without scanning to %d\n", value);
  return rt_set_value_lsbfirst (regs, 0x60, 2, value);
}
static int
rt_set_total_distance (unsigned char *regs, unsigned value)
{
  DBG (10, "Setting total distance to %d\n", value);
  return rt_set_value_lsbfirst (regs, 0x62, 2, value);
}
static int
rt_set_scanline_start (unsigned char *regs, unsigned value)
{
  return rt_set_value_lsbfirst (regs, 0x66, 2, value);
}
static int
rt_set_scanline_end (unsigned char *regs, unsigned value)
{
  return rt_set_value_lsbfirst (regs, 0x6c, 2, value);
}
static int
rt_set_basic_calibration (unsigned char *regs,
			  int redoffset1,
			  int redoffset2,
			  int redgain,
			  int greenoffset1,
			  int greenoffset2,
			  int greengain,
			  int blueoffset1, int blueoffset2, int bluegain)
{
  regs[0x02] = redoffset1;
  regs[0x05] = redoffset2;
  regs[0x08] = redgain;
  regs[0x03] = greenoffset1;
  regs[0x06] = greenoffset2;
  regs[0x09] = greengain;
  regs[0x04] = blueoffset1;
  regs[0x07] = blueoffset2;
  regs[0x0a] = bluegain;
  return 0;
}
static int
rt_set_calibration_addresses (unsigned char *regs,
			      unsigned redaddr,
			      unsigned greenaddr,
			      unsigned blueaddr,
			      unsigned endaddr,
			      unsigned width)
{
  unsigned endpage = (endaddr + 31) / 32;
  unsigned scanline_pages = ((width + 1) * 3 + 31) / 32;
  /* Red, green and blue detailed calibration addresses */
  regs[0x84] = redaddr;
  regs[0x8e] = (regs[0x8e] & 0x0f) | ((redaddr >> 4) & 0xf0);
  rt_set_value_lsbfirst (regs, 0x85, 2, greenaddr);
  rt_set_value_lsbfirst (regs, 0x87, 2, blueaddr);
  /* I don't know what the next three are used for, but each buffer commencing
   * at 0x80 and 0x82 needs to hold a full scan line.
   */
  rt_set_value_lsbfirst (regs, 0x80, 2, endpage);
  rt_set_value_lsbfirst (regs, 0x82, 2, endpage + scanline_pages);
  rt_set_value_lsbfirst (regs, 0x89, 2, endpage + scanline_pages * 2);
  /* I don't know what this is, but it seems to be a number of pages that can hold
   * 16 complete scan lines, but not calculated as an offset from any other page
   */
  rt_set_value_lsbfirst (regs, 0x51, 2, (48 * (width + 1) + 31) / 32);
  /* I don't know what this is either, but this is what the Windows driver does */
  rt_set_value_lsbfirst (regs, 0x8f, 2, 0x1c00);
  return 0;
}
static int
rt_set_lamp_duty_cycle (unsigned char *regs,
			int enable, int frequency, int offduty)
{
  if (enable)
    regs[0x3b] |= 0x80;
  else
    regs[0x3b] &= 0x7f;
  regs[0x3b] =
    (regs[0x3b] & 0x80) | ((frequency & 0x7) << 4) | (offduty & 0x0f);
  regs[0x3d] = (regs[0x3d] & 0x7f) | ((frequency & 0x8) << 4);
  return 0;
}
static int
rt_set_data_feed_on (unsigned char *regs)
{
  regs[0xb2] &= ~0x04;
  return 0;
}
static int
rt_set_data_feed_off (unsigned char *regs)
{
  regs[0xb2] |= 0x04;
  return 0;
}
static int
rt_enable_ccd (unsigned char *regs, int enable)
{
  if (enable)
    regs[0x00] &= ~0x10;
  else
    regs[0x00] |= 0x10;
  return 0;
}
static int
rt_set_cdss (unsigned char *regs, int val1, int val2)
{
  regs[0x28] = (regs[0x28] & 0xe0) | (val1 & 0x1f);
  regs[0x2a] = (regs[0x2a] & 0xe0) | (val2 & 0x1f);
  return 0;
}
static int
rt_set_cdsc (unsigned char *regs, int val1, int val2)
{
  regs[0x29] = (regs[0x29] & 0xe0) | (val1 & 0x1f);
  regs[0x2b] = (regs[0x2b] & 0xe0) | (val2 & 0x1f);
  return 0;
}
static int
rt_update_after_setting_cdss2 (unsigned char *regs)
{
  int fullcolour = (!(regs[0x2f] & 0xc0) && (regs[0x2f] & 0x04));
  int value = regs[0x2a] & 0x1f;
  regs[0x2a] = (regs[0x2a] & 0xe0) | (value & 0x1f);
  if (fullcolour)
    value *= 3;
  if ((regs[0x40] & 0xc0) == 0x40)
    value += 17;
  else
    value += 16;
  regs[0x2c] = (regs[0x2c] & 0xe0) | (value % 24);
  regs[0x2d] = (regs[0x2d] & 0xe0) | ((value + 2) % 24);
  return 0;
}
static int
rt_set_cph0s (unsigned char *regs, int on)
{
  if (on)
    regs[0x2d] |= 0x20;		/* 1200dpi horizontal coordinate space */
  else
    regs[0x2d] &= ~0x20;	/* 600dpi horizontal coordinate space */
  return 0;
}
static int
rt_set_cvtr_lm (unsigned char *regs, int val1, int val2, int val3)
{
  regs[0x28] = (regs[0x28] & ~0xe0) | (val1 << 5);
  regs[0x29] = (regs[0x29] & ~0xe0) | (val2 << 5);
  regs[0x2a] = (regs[0x2a] & ~0xe0) | (val3 << 5);
  return 0;
}
static int
rt_set_cvtr_mpt (unsigned char *regs, int val1, int val2, int val3)
{
  regs[0x3c] = (val1 & 0x0f) | (val2 << 4);
  regs[0x3d] = (regs[0x3d] & 0xf0) | (val3 & 0x0f);
  return 0;
}
static int
rt_set_cvtr_wparams (unsigned char *regs,
		     unsigned fpw, unsigned bpw, unsigned w)
{
  regs[0x31] = (w & 0x0f) | ((bpw << 4) & 0x30) | (fpw << 6);
  return 0;
}
static int
rt_enable_movement (unsigned char *regs, int enable)
{
  if (enable)
    regs[0xc3] |= 0x80;
  else
    regs[0xc3] &= ~0x80;
  return 0;
}
static int
rt_set_scan_frequency (unsigned char *regs, int frequency)
{
  regs[0x64] = (regs[0x64] & 0xf0) | (frequency & 0x0f);
  return 0;
}
static int
rt_set_merge_channels (unsigned char *regs, int on)
{
  /* RGBRGB instead of RRRRR...GGGGG...BBBB */
  regs[0x2f] &= ~0x14;
  regs[0x2f] |= on ? 0x04 : 0x10;
  return 0;
}
static int
rt_set_channel (unsigned char *regs, int channel)
{
  regs[0x2f] = (regs[0x2f] & ~0xc0) | (channel << 6);
  return 0;
}
static int
rt_set_single_channel_scanning (unsigned char *regs, int on)
{
  if (on)
    regs[0x2f] |= 0x20;
  else
    regs[0x2f] &= ~0x20;
  return 0;
}
static int
rt_set_colour_mode (unsigned char *regs, int on)
{
  if (on)
    regs[0x2f] |= 0x02;
  else
    regs[0x2f] &= ~0x02;
  return 0;
}
static int
rt_set_horizontal_resolution (unsigned char *regs, int resolution)
{
  int base_resolution = 300;
  if (regs[0x2d] & 0x20)
    base_resolution *= 2;
  if (regs[0xd3] & 0x08)
    base_resolution *= 2;
  regs[0x7a] = base_resolution / resolution;
  return 0;
}
static int
rt_set_last_sram_page (unsigned char *regs, int pagenum)
{
  rt_set_value_lsbfirst (regs, 0x8b, 2, pagenum);
  return 0;
}
static int
rt_set_step_size (unsigned char *regs, int stepsize)
{
  rt_set_value_lsbfirst (regs, 0xe2, 2, stepsize);
  rt_set_value_lsbfirst (regs, 0xe0, 2, 0);
  return 0;
}
static int
rt_set_all_registers (void const *regs_)
{
  char regs[255];
  memcpy (regs, regs_, 255);
  regs[0x32] &= ~0x40;
  if (rt_set_one_register (0x32, regs[0x32]) < 0 ||
      rt_set_register_immediate (0, 255, regs) < 0 ||
      rt_set_one_register (0x32, regs[0x32] | 0x40) < 0)
    return -1;
  return 0;
}
static int
rt_adjust_misc_registers (unsigned char *regs)
{
  /* Mostly unknown purposes - probably no need to adjust */
  regs[0xc6] = (regs[0xc6] & 0x0f) | 0x20;	/* Purpose unknown - appears to do nothing */
  regs[0x2e] = 0x86;		/* ???? - Always has this value */
  regs[0x30] = 2;		/* CCPL = 1 */
  regs[0xc9] |= 0x38;		/* Doesn't have any obvious effect, but the Windows driver does this */
  return 0;
}
#define NVR_MAX_ADDRESS_SIZE	11
#define NVR_MAX_OPCODE_SIZE	3
#define NVR_DATA_SIZE		8
#define	NVR_MAX_COMMAND_SIZE	((NVR_MAX_ADDRESS_SIZE + \
				  NVR_MAX_OPCODE_SIZE + \
				  NVR_DATA_SIZE) * 2 + 1)
static int
rt_nvram_enable_controller (int enable)
{
  unsigned char r;
  if (rt_read_register_immediate (0x1d, 1, &r) < 0)
    return -1;
  if (enable)
    r |= 1;
  else
    r &= ~1;
  return rt_set_one_register (0x1d, r);
}
static int
rt_nvram_init_command (void)
{
  unsigned char regs[13];
  if (rt_read_register_immediate (0x10, 13, regs) < 0)
    return -1;
  regs[2] |= 0xf0;
  regs[4] = (regs[4] & 0x1f) | 0x60;
  return rt_set_register_immediate (0x10, 13, regs);
}
static int
rt_nvram_init_stdvars (int block, int *addrbits, unsigned char *basereg)
{
  int bitsneeded;
  int capacity;
  switch (block)
    {
    case 0:
      bitsneeded = 7;
      break;
    case 1:
      bitsneeded = 9;
      break;
    case 2:
      bitsneeded = 11;
      break;
    default:
      bitsneeded = 0;
      capacity = 1;
      while (capacity < block)
	capacity <<= 1, ++bitsneeded;
      break;
    }
  *addrbits = bitsneeded;
  if (rt_read_register_immediate (0x10, 1, basereg) < 0)
    return -1;
  *basereg &= ~0x60;
  return 0;
}
static void
rt_nvram_set_half_bit (unsigned char *buffer,
		       int value, unsigned char stdbits, int whichhalf)
{
  *buffer = stdbits | (value ? 0x40 : 0) | (whichhalf ? 0x20 : 0);
}
static void
rt_nvram_set_command_bit (unsigned char *buffer,
			  int value, unsigned char stdbits)
{
  rt_nvram_set_half_bit (buffer, value, stdbits, 0);
  rt_nvram_set_half_bit (buffer + 1, value, stdbits, 1);
}
static void
rt_nvram_set_addressing_bits (unsigned char *buffer,
			      int location,
			      int addressingbits, unsigned char stdbits)
{
  int currentbit = 1 << (addressingbits - 1);
  while (addressingbits--)
    {
      rt_nvram_set_command_bit (buffer,
				(location & currentbit) ? 1 : 0, stdbits);
      buffer += 2;
      currentbit >>= 1;
    }
}
#if 0
static int
rt_nvram_enable_write (int addressingbits, int enable, unsigned char stdbits)
{
  unsigned char cmdbuffer[NVR_MAX_COMMAND_SIZE];
  int cmdsize = 6 + addressingbits * 2;
  rt_nvram_set_command_bit (cmdbuffer, 1, stdbits);
  rt_nvram_set_command_bit (cmdbuffer + 2, 0, stdbits);
  rt_nvram_set_command_bit (cmdbuffer + 4, 0, stdbits);
  rt_nvram_set_command_bit (cmdbuffer + 6, enable, stdbits);
  if (addressingbits > 1)
    rt_nvram_set_addressing_bits (cmdbuffer + 8, 0, addressingbits - 1,
				  stdbits);
  if (rt_nvram_enable_controller (1) < 0 ||
      rt_send_command_immediate (RTCMD_NVRAMCONTROL, 0, cmdsize, cmdsize,
				 cmdbuffer, 0, 0) < 0
      || rt_nvram_enable_controller (0) < 0)
    {
      return -1;
    }
  return 0;
}
static int
rt_nvram_write (int block, int location, char const *data, int bytes)
{
  int addressingbits;
  unsigned char stdbits;
  unsigned char cmdbuffer[NVR_MAX_COMMAND_SIZE];
  unsigned char *address_bits;
  unsigned char *data_bits;
  int cmdsize;
  /* This routine doesn't appear to work, but I can't see anything wrong with it */
  if (rt_nvram_init_stdvars (block, &addressingbits, &stdbits) < 0)
    return -1;
  cmdsize = (addressingbits + 8) * 2 + 6;
  address_bits = cmdbuffer + 6;
  data_bits = address_bits + (addressingbits * 2);
  rt_nvram_set_command_bit (cmdbuffer, 1, stdbits);
  rt_nvram_set_command_bit (cmdbuffer + 2, 0, stdbits);
  rt_nvram_set_command_bit (cmdbuffer + 4, 1, stdbits);
  if (rt_nvram_init_command () < 0 ||
      rt_nvram_enable_write (addressingbits, 1, stdbits) < 0)
    return -1;
  while (bytes--)
    {
      int i;
      rt_nvram_set_addressing_bits (address_bits, location, addressingbits,
				    stdbits);
      rt_nvram_set_addressing_bits (data_bits, *data++, 8, stdbits);
      if (rt_nvram_enable_controller (1) < 0 ||
	  rt_send_command_immediate (RTCMD_NVRAMCONTROL, 0, cmdsize, cmdsize,
				     cmdbuffer, 0, 0) < 0
	  || rt_nvram_enable_controller (0) < 0)
	return -1;
      if (rt_nvram_enable_controller (1) < 0)
	return -1;
      for (i = 0; i < cmdsize; ++i)
	{
	  unsigned char r;
	  unsigned char cmd;
	  rt_nvram_set_half_bit (&cmd, 0, stdbits, i & 1);
	  if (rt_send_command_immediate
	      (RTCMD_NVRAMCONTROL, 0, 1, 1, &cmd, 0, 0) < 0
	      || rt_read_register_immediate (0x10, 1, &r) < 0)
	    {
	      return -1;
	    }
	  else if (r & 0x80)
	    {
	      break;
	    }
	}
      if (rt_nvram_enable_controller (0) < 0)
	return -1;
      ++location;
    }
  if (rt_nvram_enable_write (addressingbits, 0, stdbits) < 0)
    return -1;
  return 0;
}
#endif
static int
rt_nvram_read (int block, int location, unsigned char *data, int bytes)
{
  int addressingbits;
  unsigned char stdbits;
  unsigned char cmdbuffer[NVR_MAX_COMMAND_SIZE];
  unsigned char *address_bits;
  unsigned char readbit_command[2];
  int cmdsize;
  if (rt_nvram_init_stdvars (block, &addressingbits, &stdbits) < 0)
    return -1;
  cmdsize = addressingbits * 2 + 7;
  address_bits = cmdbuffer + 6;
  rt_nvram_set_command_bit (cmdbuffer, 1, stdbits);
  rt_nvram_set_command_bit (cmdbuffer + 2, 1, stdbits);
  rt_nvram_set_command_bit (cmdbuffer + 4, 0, stdbits);
  rt_nvram_set_half_bit (cmdbuffer + cmdsize - 1, 0, stdbits, 0);
  rt_nvram_set_half_bit (readbit_command, 0, stdbits, 1);
  rt_nvram_set_half_bit (readbit_command + 1, 0, stdbits, 0);
  if (rt_nvram_init_command () < 0)
    return -1;
  while (bytes--)
    {
      char c = 0;
      unsigned char r;
      int i;
      rt_nvram_set_addressing_bits (address_bits, location, addressingbits,
				    stdbits);
      if (rt_nvram_enable_controller (1) < 0 ||
	  rt_send_command_immediate (RTCMD_NVRAMCONTROL, 0x1d, cmdsize,
				     cmdsize, cmdbuffer, 0, 0) < 0)
	return -1;
      for (i = 0; i < 8; ++i)
	{
	  c <<= 1;
	  if (rt_send_command_immediate
	      (RTCMD_NVRAMCONTROL, 0x1d, 2, 2, readbit_command, 0, 0) < 0
	      || rt_read_register_immediate (0x10, 1, &r) < 0)
	    return -1;
	  if (r & 0x80)
	    c |= 1;
	}
      if (rt_nvram_enable_controller (0) < 0)
	return -1;
      *data++ = c;
      ++location;
    }
  return 0;
}
/* This is what we want as the initial registers, not what they
 * are at power on time. In particular 13 bytes at 0x10 are
 * different, and the byte at 0x94 is different.
 */
static unsigned char initial_regs[] = {
  /* 0x00 */ 0xf5, 0x41, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0x08 */ 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0x00,
  /* 0x10 */ 0x81, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00,
  /* 0x18 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00,
  /* 0x20 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0x28 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x06, 0x19,
  /* 0x30 */ 0xd0, 0x7a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0x38 */ 0x00, 0x00, 0xa0, 0x37, 0xff, 0x0f, 0x00, 0x00,
  /* 0x40 */ 0x80, 0x00, 0x00, 0x00, 0x8c, 0x76, 0x00, 0x00,
  /* 0x48 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0x50 */ 0x20, 0xbc, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0x58 */ 0x1d, 0x1f, 0x00, 0x1f, 0x00, 0x00, 0x00, 0x00,
  /* 0x60 */ 0x5e, 0xea, 0x5f, 0xea, 0x00, 0x80, 0x64, 0x00,
  /* 0x68 */ 0x00, 0x00, 0x00, 0x00, 0x84, 0x04, 0x00, 0x00,
  /* 0x70 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0x78 */ 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0x80 */ 0x0f, 0x02, 0x4b, 0x02, 0x00, 0xec, 0x19, 0xd8,
  /* 0x88 */ 0x2d, 0x87, 0x02, 0xff, 0x3f, 0x78, 0x60, 0x00,
  /* 0x90 */ 0x1c, 0x00, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x00,
  /* 0x98 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xa0 */ 0x00, 0x00, 0x00, 0x0c, 0x27, 0x64, 0x00, 0x00,
  /* 0xa8 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xb0 */ 0x12, 0x08, 0x06, 0x04, 0x00, 0x00, 0x00, 0x00,
  /* 0xb8 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xc0 */ 0x00, 0x00, 0x80, 0x00, 0x10, 0x00, 0x00, 0x00,
  /* 0xc8 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xd0 */ 0xff, 0xbf, 0xff, 0xff, 0x00, 0x00, 0xff, 0xff,
  /* 0xd8 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xe0 */ 0x00, 0x00, 0x0f, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xe8 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xf0 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 0xf8 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#define RT_NORMAL_TG 0
#define RT_DOUBLE_TG 1
#define RT_TRIPLE_TG 2
#define RT_DDOUBLE_TG 3
#define RT_300_TG 4
#define RT_150_TG 5
#define RT_TEST_TG 6
static struct tg_info__
{
  int tg_cph0p;
  int tg_crsp;
  int tg_cclpp;
  int tg_cph0s;
  int tg_cdss1;
  int tg_cdsc1;
  int tg_cdss2;
  int tg_cdsc2;
} tg_info[] =
{
  /* CPH              CCD Shifting Clock
   *    0P            ??? Perhaps CCD rising edge position
   *    0S            ???
   * CRS              Reset CCD Clock
   *    P             ??? Perhaps CCD falling edge position
   * CCLP             CCD Clamp Clock
   *     P            ???
   * CDS              ???
   *    S1            ???
   *    S2            ???
   *    C1            ???
   *    C2            ???
   */
  /*CPH0P     CRSP      CCLPP     CPH0S CDSS1 CDSC1 CDSS2 CDSC2 */
  {
  0x01FFE0, 0x3c0000, 0x003000, 1, 0xb, 0xd, 0x00, 0x01},	/* NORMAL */
  {
  0x7ff800, 0xf00000, 0x01c000, 0, 0xb, 0xc, 0x14, 0x15},	/* DOUBLE */
  {
  0x033fcc, 0x300000, 0x060000, 1, 0x8, 0xa, 0x00, 0x01},	/* TRIPLE */
  {
  0x028028, 0x300000, 0x060000, 1, 0x8, 0xa, 0x00, 0x01},	/* DDOUBLE */
  {
  0x7ff800, 0x030000, 0x060000, 0, 0xa, 0xc, 0x17, 0x01},	/* 300 */
  {
  0x7fc700, 0x030000, 0x060000, 0, 0x7, 0x9, 0x17, 0x01},	/* 150 */
  {
  0x7ff800, 0x300000, 0x060000, 0, 0xa, 0xc, 0x17, 0x01},	/* TEST */
};
struct resolution_parameters
{
  unsigned resolution;
  int reg_39_value;
  int reg_c3_value;
  int reg_c6_value;
  int scan_frequency;
  int cph0s;
  int red_green_offset;
  int green_blue_offset;
  int intra_channel_offset;
  int motor_movement_clock_multiplier;
  int d3_bit_3_value;
  int tg;
  int step_size;
};
/* The TG value sets seem to affect the exposure time:
 * At 200dpi:
 * NORMAL gets higher values than DOUBLE
 * DDOUBLE gives a crazy spike in the data
 * TRIPLE gives a black result
 * TEST gives a black result
 * 300 gives a black result
 * 150 gives a black result
 */
static struct resolution_parameters resparms[] = {
  /* Acceptable values for stepsz are:
   * 0x157b 0xabd, 0x55e, 0x2af, 0x157, 0xab, 0x55
   */
  /* My values - all work */
  /*res   r39 rC3 rC6 freq cph0s rgo gbo intra mmcm d3 tg            stepsz */
  {1200, 3, 6, 4, 2, 1, 22, 22, 4, 2, 1, RT_NORMAL_TG, 0x157b},
  {600, 15, 6, 4, 1, 1, 9, 10, 0, 2, 1, RT_NORMAL_TG, 0x055e},
  {400, 3, 1, 4, 1, 1, 6, 6, 1, 2, 1, RT_NORMAL_TG, 0x157b},
  {300, 15, 3, 4, 1, 1, 5, 4, 0, 2, 1, RT_NORMAL_TG, 0x02af},
  {200, 7, 1, 4, 1, 1, 3, 3, 0, 2, 1, RT_NORMAL_TG, 0x055e},
  {150, 15, 3, 1, 1, 1, 2, 2, 0, 2, 1, RT_NORMAL_TG, 0x02af},
  {100, 3, 1, 3, 1, 1, 1, 1, 0, 2, 1, RT_NORMAL_TG, 0x0abd},
  {75, 15, 3, 3, 1, 1, 1, 1, 0, 2, 1, RT_NORMAL_TG, 0x02af},
  {50, 15, 1, 1, 1, 1, 0, 0, 0, 2, 1, RT_NORMAL_TG, 0x055e},
  {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
};
struct dcalibdata
{
  unsigned char *buffers[3];
  int pixelsperrow;
  int pixelnow;
  int channelnow;
  int firstrowdone;
};
static void dump_registers (unsigned char const *);
static int
rts8801_rewind (void)
{
  unsigned char regs[255];
  int n;
  int tg_setting = RT_DOUBLE_TG;
  rt_read_register_immediate (0, 255, regs);
  rt_set_noscan_distance (regs, 59998);
  rt_set_total_distance (regs, 59999);
  rt_set_stop_when_rewound (regs, 0);
  rt_set_one_register (0xc6, 0);
  rt_set_one_register (0xc6, 0);
  rt_set_direction_rewind (regs);
  rt_set_step_size (regs, 0x55);
  regs[0x39] = 3;
  regs[0xc3] = (regs[0xc3] & 0xf8) | 0x86;
  regs[0xc6] = (regs[0xc6] & 0xf8) | 4;
  rt_set_horizontal_resolution (regs, 25);
  rt_set_ccd_shift_clock_multiplier (regs, tg_info[tg_setting].tg_cph0p);
  rt_set_ccd_clock_reset_interval (regs, tg_info[tg_setting].tg_crsp);
  rt_set_ccd_clamp_clock_multiplier (regs, tg_info[tg_setting].tg_cclpp);
  rt_set_cdss (regs, tg_info[tg_setting].tg_cdss1,
	       tg_info[tg_setting].tg_cdss2);
  rt_set_cdsc (regs, tg_info[tg_setting].tg_cdsc1,
	       tg_info[tg_setting].tg_cdsc2);
  rt_update_after_setting_cdss2 (regs);
  rt_set_cvtr_wparams (regs, 3, 0, 6);
  rt_set_cvtr_mpt (regs, 15, 15, 15);
  rt_set_cvtr_lm (regs, 7, 7, 7);
  rt_set_motor_type (regs, 2);
  if (DBG_LEVEL >= 5)
    dump_registers (regs);
  rt_set_all_registers (regs);
  rt_set_one_register (0x2c, regs[0x2c]);
  rt_start_moving ();
  while (!rt_is_rewound () &&
	 ((n = rt_get_available_bytes ()) > 0 || rt_is_moving () > 0))
    {
      if (n)
	{
	  char buffer[0xffc0];
	  if (n > (int) sizeof (buffer))
	    n = sizeof (buffer);
	  rt_get_data (n, buffer);
	}
      else
	{
	  usleep (10000);
	}
    }
  rt_stop_moving ();
  return 0;
}
static int cancelled_scan = 0;
static unsigned
get_lsbfirst_int (unsigned char const *p, int n)
{
  unsigned value = *p++;
  int shift = 8;
  while (--n)
    {
      unsigned now = *p++;
      value |= now << shift;
      shift += 8;
    }
  return value;
}
static int
convert_c6 (int i)
{
  switch (i)
    {
    case 3:
      return 1;
    case 1:
      return 2;
    case 4:
      return 4;
    }
  return -1;
}
static void
dump_registers (unsigned char const *regs)
{
  int i = 0;
  long pixels;
  DBG (5, "Scan commencing with registers:\n");
  while (i < 255)
    {
      int j = 0;
      char buffer[80];
      buffer[0] = 0;
      sprintf (buffer + strlen (buffer), "%02x:", i);
      while (j < 8)
	{
	  sprintf (buffer + strlen (buffer), " %02x", regs[i++]);
	  j++;
	}
      sprintf (buffer + strlen (buffer), " -");
      while (j++ < 16 && i < 255)
	sprintf (buffer + strlen (buffer), " %02x", regs[i++]);
      DBG (5, "    %s\n", buffer);
    }
  DBG (5, "  Position:\n");
  DBG (5, "    Distance without scanning:       %u\n",
       get_lsbfirst_int (regs + 0x60, 2));
  DBG (5, "    Total distance:                  %u\n",
       get_lsbfirst_int (regs + 0x62, 2));
  DBG (5, "    Scanning distance:               %u\n",
       get_lsbfirst_int (regs + 0x62, 2) - get_lsbfirst_int (regs + 0x60, 2));
  DBG (5, "    Direction:                       %s\n",
       (regs[0xc6] & 0x08) ? "forward" : "rewind");
  DBG (5, "    Motor:                           %s\n",
       (regs[0xc3] & 0x80) ? "enabled" : "disabled");
  if (regs[0x7a])
    DBG (5, "    X range:                         %u-%u\n",
	 get_lsbfirst_int (regs + 0x66, 2) / regs[0x7a],
	 get_lsbfirst_int (regs + 0x6c, 2) / regs[0x7a]);
  DBG (5, "  TG Info:\n");
  DBG (5, "    CPH0P:                           %06x\n",
       get_lsbfirst_int (regs + 0xf0, 3));
  DBG (5, "    CRSP:                            %06x\n",
       get_lsbfirst_int (regs + 0xf9, 3));
  DBG (5, "    CCLPP:                           %06x\n",
       get_lsbfirst_int (regs + 0xfc, 3));
  DBG (5, "    CPH0S:                           %d\n",
       (regs[0x2d] & 0x20) ? 1 : 0);
  DBG (5, "    CDSS1:                           %02x\n", regs[0x28] & 0x1f);
  DBG (5, "    CDSC1:                           %02x\n", regs[0x29] & 0x1f);
  DBG (5, "    CDSS2:                           %02x\n", regs[0x2a] & 0x1f);
  DBG (5, "    CDSC2:                           %02x\n", regs[0x2b] & 0x1f);
  DBG (5, "  Resolution specific:\n");
  if (!regs[0x7a])
    DBG (5, "    Horizontal resolution:           Denominator is zero!\n");
  else
    DBG (5, "    Horizontal resolution:           %u\n", 300
	 * ((regs[0x2d] & 0x20) ? 2 : 1)
	 * ((regs[0xd3] & 0x08) ? 2 : 1) / regs[0x7a]);
  DBG (5, "    Derived vertical resolution:     %u\n",
       400 * (regs[0xc3] & 0x1f) * convert_c6 (regs[0xc6] & 0x7) /
       (regs[0x39] + 1));
  DBG (5, "    Register D3:3                    %u\n",
       (regs[0xd3] & 0x08) ? 1 : 0);
  DBG (5, "    Register 39:                     %u\n", regs[0x39]);
  DBG (5, "    Register C3:0-5:                 %u\n", regs[0xc3] & 0x1f);
  DBG (5, "    Register C6:0-2:                 %u\n", regs[0xc6] & 0x7);
  DBG (5, "    Motor movement clock multiplier: %u\n", regs[0x40] >> 6);
  DBG (5, "    Step Size:                       %04x\n",
       get_lsbfirst_int (regs + 0xe2, 2));
  DBG (5, "    Frequency:                       %u\n", regs[0x64] & 0xf);
  DBG (5, "  Colour registers\n");
  DBG (5, "    Register 2F:                     %02x\n", regs[0x2f]);
  DBG (5, "    Register 2C:                     %02x\n", regs[0x2c]);
  if (regs[0x7a])
    {
      DBG (5, "  Scan data estimates:\n");
      pixels =
	(long) (get_lsbfirst_int (regs + 0x62, 2) -
		get_lsbfirst_int (regs + 0x60,
				  2)) * (long) (get_lsbfirst_int (regs + 0x6c,
								  2) -
						get_lsbfirst_int (regs + 0x66,
								  2)) /
	regs[0x7a];
      DBG (5, "    Pixels:                          %ld\n", pixels);
      DBG (5, "    Bytes at 24BPP:                  %ld\n", pixels * 3);
      DBG (5, "    Bytes at 1BPP:                   %ld\n", pixels / 8);
    }
  DBG (5, "\n");
}
static int
constrain (int val, int min, int max)
{
  if (val < min)
    {
      DBG (10, "Clipped %d to %d\n", val, min);
      val = min;
    }
  else if (val > max)
    {
      DBG (10, "Clipped %d to %d\n", val, max);
      val = max;
    }
  return val;
}
#if 0
static void
sram_dump_byte(FILE *fp,
               unsigned char const *left,
               unsigned leftstart,
               unsigned leftlimit,
               unsigned char const *right,
               unsigned rightstart,
               unsigned rightlimit,
               unsigned idx)
{
  unsigned ridx = rightstart + idx;
  unsigned lidx = leftstart + idx;
  putc(' ', fp);
  if (rightstart < rightlimit && leftstart < leftlimit && left[lidx] != right[ridx])
    fputs("", fp);
  if (leftstart < leftlimit)
    fprintf(fp, "%02x", left[lidx]);
  else
    fputs("  ", fp);
  if (rightstart < rightlimit && leftstart < leftlimit && left[lidx] != right[ridx])
    fputs("", fp);
}
static void
dump_sram_to_file(char const *fname,
                  unsigned char const *expected,
                  unsigned end_calibration_offset)
{
  FILE *fp = fopen(fname, "w");
  rt_set_sram_page(0);
  if (fp)
    {
      unsigned char buf[1024];
      unsigned loc = 0;
      fprintf(fp, "\n");
      while (loc < end_calibration_offset)
        {
          unsigned byte = 0;
          rt_read_sram(1024, buf);
          while (byte < 1024)
            {
              unsigned idx = 0;
              fprintf(fp, "%06x:", loc);
              do
                {
		  sram_dump_byte(fp, buf, byte, 1024, expected, loc, end_calibration_offset, idx);
                } while (++idx & 0x7);
              fprintf(fp, " -");
              do
                {
		  sram_dump_byte(fp, buf, byte, 1024, expected, loc, end_calibration_offset, idx);
                } while (++idx & 0x7);
              idx = 0;
              fputs("     ", fp);
              do
                {
                  sram_dump_byte(fp, expected, loc, end_calibration_offset, buf, byte, 1024, idx);
                } while (++idx & 0x7);
              fprintf(fp, " -");
              do
                {
                  sram_dump_byte(fp, expected, loc, end_calibration_offset, buf, byte, 1024, idx);
                } while (++idx & 0x7);
              fputs("\n", fp);
              byte += 16;
              loc += 16;
            }
        }
      fprintf(fp, "");
      fclose(fp);
    }
}
#endif
static int
rts8801_doscan (unsigned width,
		unsigned height,
		unsigned colour,
		unsigned red_green_offset,
		unsigned green_blue_offset,
		unsigned intra_channel_offset,
		rts8801_callback cbfunc,
		void *params,
		int oddfirst,
		unsigned char const *calib_info,
		int merged_channels,
		double *postprocess_offsets,
		double *postprocess_gains)
{
  unsigned rowbytes = 0;
  unsigned output_rowbytes = 0;
  unsigned channels = 0;
  unsigned total_rows = 0;
  unsigned char *row_buffer;
  unsigned char *output_buffer;
  unsigned buffered_rows;
  int rows_to_begin;
  int rowbuffer_bytes;
  int n;
  unsigned rownow = 0;
  unsigned bytenow = 0;
  unsigned char *channel_data[3][2];
  unsigned i;
  unsigned j;
  int result = 0;
  unsigned rows_supplied = 0;
  calib_info = calib_info;	/* Kill warning */
  if (cancelled_scan)
    return -1;
  rt_start_moving ();
  channels = 3;
  rowbytes = width * 3;
  switch (colour)
    {
    case HP3500_GRAY_SCAN:
      output_rowbytes = width;
      break;
    case HP3500_COLOR_SCAN:
      output_rowbytes = rowbytes;
      break;
    case HP3500_LINEART_SCAN:
      output_rowbytes = (width + 7) / 8;
      break;
    }
  buffered_rows =
    red_green_offset + green_blue_offset + intra_channel_offset + 1;
  rows_to_begin = buffered_rows;
  rowbuffer_bytes = buffered_rows * rowbytes;
  row_buffer = (unsigned char *) malloc (rowbuffer_bytes);
  output_buffer = (unsigned char *) malloc (rowbytes);
  for (i = j = 0; i < channels; ++i)
    {
      if (i == 1)
	j += red_green_offset;
      else if (i == 2)
	j += green_blue_offset;
      if (merged_channels)
	channel_data[i][1 - oddfirst] = row_buffer + rowbytes * j + i;
      else
	channel_data[i][1 - oddfirst] = row_buffer + rowbytes * j + width * i;
      channel_data[i][oddfirst] =
	channel_data[i][1 - oddfirst] + rowbytes * intra_channel_offset;
    }
  while (((n = rt_get_available_bytes ()) > 0 || rt_is_moving () > 0)
	 && !cancelled_scan)
    {
      if (n == 1 && (rt_is_moving () || rt_get_available_bytes () != 1))
	n = 0;
      if (n > 0)
	{
	 unsigned char buffer[0xffc0];
	  if (n > 0xffc0)
	    n = 0xffc0;
	  else if ((n > 1) && (n & 1))
	    --n;
	  if (rt_get_data (n, buffer) >= 0)
	    {
	      unsigned char *bufnow = buffer;
	      while (n)
		{
		  int numcopy = rowbytes - bytenow;
		  if (numcopy > n)
		    numcopy = n;
		  memcpy (row_buffer + rownow * rowbytes + bytenow,
		  	  bufnow, numcopy);
		  bytenow += numcopy;
		  bufnow += numcopy;
		  n -= numcopy;
		  if (bytenow == rowbytes)
		    {
		      if (!rows_to_begin || !--rows_to_begin)
			{
			  unsigned char *outnow = output_buffer;
                          unsigned x;
			  for (i = x = 0;
			       x < width;
			       ++x, i += merged_channels ? channels : 1)
			    {
			      for (j = 0; j < channels; ++j)
				{
				  unsigned pix =
				    (unsigned char) channel_data[j][i & 1][i];
                                  if (postprocess_gains && postprocess_offsets)
                                  {
                                    int ppidx = j * width + x;
                                    pix = constrain ( pix
                                                       * postprocess_gains[ppidx]
                                                       - postprocess_offsets[ppidx],
                                                      0,
                                                      255);
                                  }
				  *outnow++ = pix;
				}
			    }
			  if (colour == HP3500_GRAY_SCAN || colour == HP3500_LINEART_SCAN)
			    {
			      unsigned char const *in_now = output_buffer;
			      int	bit = 7;
			      outnow = output_buffer;
			      for (i = 0; i < width; ++i)
				{
				  if (colour == HP3500_GRAY_SCAN)
				    {
				      *outnow++ = ((unsigned) in_now[0] * 2989 +
						   (unsigned) in_now[1] * 5870 +
						   (unsigned) in_now[2] * 1140) / 10000;
				    }
				  else
				    {
				      if (bit == 7)
					*outnow = ((in_now[1] < 0x80) ? 0x80 : 0);
				      else if (in_now[1] < 0x80)
					*outnow |= (1 << bit);
				      if (bit == 0)
					{
					  ++outnow;
					  bit = 7;
					}
				      else
					{
					  --bit;
					}
				    }
				  in_now += 3;
				}
			    }
			  if (rows_supplied++ < height &&
			      !((*cbfunc) (params, output_rowbytes, output_buffer)))
			    break;
			  for (i = 0; i < channels; ++i)
			    {
			      for (j = 0; j < 2; ++j)
				{
				  channel_data[i][j] += rowbytes;
				  if (channel_data[i][j] - row_buffer >=
				      rowbuffer_bytes)
				    channel_data[i][j] -= rowbuffer_bytes;
				}
			    }
			}
		      ++total_rows;
		      if (++rownow == buffered_rows)
			rownow = 0;
		      bytenow = 0;
		    }
		}
	    }
	  DBG (30, "total_rows = %d\r", total_rows);
	}
      else
	{
	  usleep (10000);
	}
    }
  DBG (10, "\n");
  if (n < 0)
    result = -1;
  free (output_buffer);
  free (row_buffer);
  rt_stop_moving ();
  return result;
}
static unsigned local_sram_size;
static unsigned char r93setting;
#define RTS8801_F_SUPPRESS_MOVEMENT	1
#define	RTS8801_F_LAMP_OFF		2
#define RTS8801_F_NO_DISPLACEMENTS	4
#define RTS8801_F_ODDX			8
static int
find_resolution_index (unsigned resolution)
{
  int res = 0;
  for (res = 0; resparms[res].resolution != resolution; ++res)
    {
      if (!resparms[res].resolution)
	return -1;
    }
  return res;
}
static int
rts8801_fullscan (unsigned x,
		  unsigned y,
		  unsigned w,
		  unsigned h,
		  unsigned xresolution,
		  unsigned yresolution,
		  unsigned colour,
		  rts8801_callback cbfunc,
		  void *param,
		  unsigned char *calib_info,
		  int flags,
		  int red_calib_offset,
		  int green_calib_offset,
		  int blue_calib_offset,
		  int end_calib_offset,
                  double *postprocess_offsets,
                  double *postprocess_gains)
{
  int ires, jres;
  int tg_setting;
  unsigned char regs[256];
  unsigned char offdutytime;
  int result;
  int scan_frequency;
  unsigned intra_channel_offset;
  unsigned red_green_offset;
  unsigned green_blue_offset;
  unsigned total_offsets;
  ires = find_resolution_index (xresolution);
  jres = find_resolution_index (yresolution);
  if (ires < 0 || jres < 0)
    return -1;
  /* Set scan parameters */
  rt_read_register_immediate (0, 255, regs);
  regs[255] = 0;
  rt_enable_ccd (regs, 1);
  rt_enable_movement (regs, 1);
  rt_set_scan_frequency (regs, 1);
  rt_adjust_misc_registers (regs);
  rt_set_cvtr_wparams (regs, 3, 0, 6);
  rt_set_cvtr_mpt (regs, 15, 15, 15);
  rt_set_cvtr_lm (regs, 7, 7, 7);
  rt_set_motor_type (regs, 2);
  if (rt_nvram_read (0, 0x7b, &offdutytime, 1) < 0 || offdutytime >= 15)
    {
      offdutytime = 6;
    }
  rt_set_lamp_duty_cycle (regs, 1,	/* On */
			  10,	/* Frequency */
			  offdutytime);	/* Off duty time */
  rt_set_movement_pattern (regs, 0x800000);
  rt_set_direction_forwards (regs);
  rt_set_stop_when_rewound (regs, 0);
  rt_set_calibration_addresses (regs, 0, 0, 0, 0, 0);
  rt_set_basic_calibration (regs,
			    calib_info[0], calib_info[1], calib_info[2],
			    calib_info[3], calib_info[4], calib_info[5],
			    calib_info[6], calib_info[7], calib_info[8]);
  regs[0x0b] = 0x70;		/* If set to 0x71, the alternative, all values are low */
  regs[0x40] &= 0xc0;
  if (red_calib_offset >= 0
      && green_calib_offset >= 0
      && blue_calib_offset >= 0)
    {
      rt_set_calibration_addresses (regs, red_calib_offset,
				    green_calib_offset, blue_calib_offset,
				    end_calib_offset,
				    w);
      regs[0x40] |= 0x2f;
    }
  else if (end_calib_offset >= 0)
    {
      rt_set_calibration_addresses (regs, 0x600, 0x600, 0x600,
				    end_calib_offset, w);
    }
  rt_set_channel (regs, RT_CHANNEL_ALL);
  rt_set_single_channel_scanning (regs, 0);
  rt_set_merge_channels (regs, 1);
  rt_set_colour_mode (regs, 1);
  rt_set_last_sram_page (regs, (local_sram_size - 1) >> 5);
  scan_frequency = resparms[jres].scan_frequency;
  rt_set_cph0s (regs, resparms[ires].cph0s);
  if (resparms[ires].d3_bit_3_value)
    regs[0xd3] |= 0x08;
  else
    regs[0xd3] &= 0xf7;
  if (flags & RTS8801_F_SUPPRESS_MOVEMENT)
    regs[0xc3] &= 0x7f;
  regs[0xb2] &= 0xf7;
  rt_set_horizontal_resolution (regs, xresolution);
  rt_set_scanline_start (regs,
			 x * (1200 / xresolution) /
			 (resparms[ires].cph0s ? 1 : 2) /
			 (resparms[ires].d3_bit_3_value ? 1 : 2));
  rt_set_scanline_end (regs,
		       (x +
			w) * (1200 / xresolution) /
		       (resparms[ires].cph0s ? 1 : 2) /
		       (resparms[ires].d3_bit_3_value ? 1 : 2));
  if (flags & RTS8801_F_NO_DISPLACEMENTS)
    {
      red_green_offset = green_blue_offset = intra_channel_offset = 0;
    }
  else
    {
      red_green_offset = resparms[jres].red_green_offset;
      green_blue_offset = resparms[jres].green_blue_offset;
      intra_channel_offset = resparms[jres].intra_channel_offset;
    }
  total_offsets = red_green_offset + green_blue_offset + intra_channel_offset;
  if (y > total_offsets + 2)
    y -= total_offsets;
  h += total_offsets;
  if (yresolution > 75 && !(flags & RTS8801_F_SUPPRESS_MOVEMENT))
    {
      int rmres = find_resolution_index (50);
      if (rmres >= 0)
	{
	  int factor = yresolution / 50;
	  int fastres = y / factor;
	  int remainder = y % factor;
	  while (remainder < 2)
	    {
		--fastres;
		remainder += factor;
	    }
	  if (fastres >= 3)
	    {
	      y = remainder;
	      rt_set_noscan_distance(regs, fastres * resparms[rmres].scan_frequency - 2);
	      rt_set_total_distance(regs, fastres * resparms[rmres].scan_frequency - 1);
	      rt_set_scan_frequency(regs, 1);
	      tg_setting = resparms[rmres].tg;
	      rt_set_ccd_shift_clock_multiplier (regs, tg_info[tg_setting].tg_cph0p);
	      rt_set_ccd_clock_reset_interval (regs, tg_info[tg_setting].tg_crsp);
	      rt_set_ccd_clamp_clock_multiplier (regs, tg_info[tg_setting].tg_cclpp);
	      rt_set_one_register (0xc6, 0);
	      rt_set_one_register (0xc6, 0);
	      rt_set_step_size (regs, resparms[rmres].step_size);
	      rt_set_motor_movement_clock_multiplier (regs,
						      resparms[rmres].
							  motor_movement_clock_multiplier);
	      rt_set_cdss (regs, tg_info[tg_setting].tg_cdss1,
			   tg_info[tg_setting].tg_cdss2);
	      rt_set_cdsc (regs, tg_info[tg_setting].tg_cdsc1,
			   tg_info[tg_setting].tg_cdsc2);
	      rt_update_after_setting_cdss2 (regs);
	      regs[0x39] = resparms[rmres].reg_39_value;
	      regs[0xc3] = (regs[0xc3] & 0xf8) | resparms[rmres].reg_c3_value;
	      regs[0xc6] = (regs[0xc6] & 0xf8) | resparms[rmres].reg_c6_value;
	      rt_set_data_feed_off (regs);
	      rt_set_all_registers (regs);
  	      rt_set_one_register (0x2c, regs[0x2c]);
	      if (DBG_LEVEL >= 5)
	        dump_registers (regs);
	      rt_start_moving ();
	      while (rt_is_moving ());
	    }
	}
    }
  rt_set_noscan_distance (regs, y * scan_frequency - 1);
  rt_set_total_distance (regs, scan_frequency * (y + h) - 1);
  rt_set_scan_frequency (regs, scan_frequency);
  tg_setting = resparms[jres].tg;
  rt_set_ccd_shift_clock_multiplier (regs, tg_info[tg_setting].tg_cph0p);
  rt_set_ccd_clock_reset_interval (regs, tg_info[tg_setting].tg_crsp);
  rt_set_ccd_clamp_clock_multiplier (regs, tg_info[tg_setting].tg_cclpp);
  rt_set_one_register (0xc6, 0);
  rt_set_one_register (0xc6, 0);
  rt_set_step_size (regs, resparms[jres].step_size);
  rt_set_motor_movement_clock_multiplier (regs,
					  resparms[jres].
					  motor_movement_clock_multiplier);
  rt_set_cdss (regs, tg_info[tg_setting].tg_cdss1,
	       tg_info[tg_setting].tg_cdss2);
  rt_set_cdsc (regs, tg_info[tg_setting].tg_cdsc1,
	       tg_info[tg_setting].tg_cdsc2);
  rt_update_after_setting_cdss2 (regs);
  regs[0x39] = resparms[jres].reg_39_value;
  regs[0xc3] = (regs[0xc3] & 0xf8) | resparms[jres].reg_c3_value;
  regs[0xc6] = (regs[0xc6] & 0xf8) | resparms[jres].reg_c6_value;
  rt_set_data_feed_on (regs);
  rt_set_all_registers (regs);
  rt_set_one_register (0x2c, regs[0x2c]);
  if (DBG_LEVEL >= 5)
    dump_registers (regs);
  result = rts8801_doscan (w,
			   h,
			   colour,
			   red_green_offset,
			   green_blue_offset,
			   intra_channel_offset,
			   cbfunc, param, (x & 1), calib_info,
			   (regs[0x2f] & 0x04) != 0,
                           postprocess_offsets,
                           postprocess_gains);
  return result;
}
static int
accumfunc (struct dcalibdata *dcd, int bytes, char *data)
{
  unsigned char *c = (unsigned char *) data;
  while (bytes > 0)
    {
      if (dcd->firstrowdone)
	dcd->buffers[dcd->channelnow][dcd->pixelnow - dcd->pixelsperrow] = *c;
      if (++dcd->channelnow >= 3)
	{
	  dcd->channelnow = 0;
	  if (++dcd->pixelnow == dcd->pixelsperrow)
	    ++dcd->firstrowdone;
	}
      c++;
      bytes--;
    }
  return 1;
}
static int
calcmedian (unsigned char const *data,
	    int pixel, int pixels_per_row, int elements)
{
  int tallies[256];
  int i;
  int elemstogo = elements / 2;
  memset (tallies, 0, sizeof (tallies));
  data += pixel;
  for (i = 0; i < elements; ++i)
    {
      ++tallies[*data];
      data += pixels_per_row;
    }
  i = 0;
  while (elemstogo - tallies[i] > 0)
    elemstogo -= tallies[i++];
  return i;
}
struct calibdata
{
  unsigned char *buffer;
  int space;
};
static int
storefunc (struct calibdata *cd, int bytes, char *data)
{
  if (cd->space > 0)
    {
      if (bytes > cd->space)
	bytes = cd->space;
      memcpy (cd->buffer, data, bytes);
      cd->buffer += bytes;
      cd->space -= bytes;
    }
  return 1;
}
static unsigned
sum_channel (unsigned char *p, int n, int bytwo)
{
  unsigned v = 0;
  while (n-- > 0)
    {
      v += *p;
      p += 3;
      if (bytwo)
	p += 3;
    }
  return v;
}
static int do_warmup = 1;
#define DETAILED_PASS_COUNT		3
#define DETAILED_PASS_OFFSETS		0
#define	DETAILED_PASS_GAINS_FIRSTPASS	1
#define	DETAILED_PASS_GAINS_SECONDPASS	2
static int
rts8801_scan (unsigned x,
	      unsigned y,
	      unsigned w,
	      unsigned h,
	      unsigned resolution,
	      unsigned colour,
	      unsigned brightness,
	      unsigned contrast,
	      rts8801_callback cbfunc,
	      void *param,
	      double gamma)
{
  unsigned char calib_info[9];
  unsigned char calibbuf[2400];
  struct dcalibdata dcd;
  struct calibdata cd;
  unsigned char *detail_buffer = 0;
  int iCalibY;
  int iCalibTarget;
  int iMoveFlags = 0;
  unsigned aiBestOffset[6];
  int aiPassed[6];
  int i;
  unsigned j;
  int k;
  int calibration_size;
  unsigned char *pDetailedCalib;
  int red_calibration_offset;
  int green_calibration_offset;
  int blue_calibration_offset;
  int end_calibration_offset;
  int base_resolution;
  int resolution_divisor;
  int resolution_index;
  int detailed_calibration_rows = 50;
  unsigned char *tdetail_buffer;
  int pass;
  int onechanged;
  double *postprocess_gains;
  double *postprocess_offsets;
  int needs_postprocessed_calibration = 0;
  double contrast_adjust = (double) contrast / 64;
  int brightness_adjust = brightness - 0x80;
  /* Initialise and power up */
  rt_set_all_registers (initial_regs);
  rt_set_powersave_mode (0);
  /* Initial rewind in case scanner is stuck away from home position */
  rts8801_rewind ();
  /* Detect SRAM */
  rt_detect_sram (&local_sram_size, &r93setting);
  /* Warm up the lamp */
  DBG (10, "Warming up the lamp\n");
  rt_turn_on_lamp ();
  if (do_warmup)
    sleep (25);
  /* Basic calibration */
  DBG (10, "Calibrating (stage 1)\n");
  calib_info[2] = calib_info[5] = calib_info[8] = 1;
  iCalibY = (resolution == 25) ? 1 : 2;
  iCalibTarget = 550;
  rt_turn_off_lamp();
  for (i = 0; i < 6; ++i)
    {
      aiBestOffset[i] = 0xbf;
      aiPassed[i] = 0;
    }
  do
    {
      DBG (30, "Initial calibration pass commences\n");
      onechanged = 0;
      for (i = 0; i < 3; ++i)
        {
	  calib_info[i * 3] = aiBestOffset[i];
	  calib_info[i * 3 + 1] = aiBestOffset[i + 3];
        }
      cd.buffer = calibbuf;
      cd.space = sizeof (calibbuf);
      DBG (30, "Commencing scan for initial calibration pass\n");
      rts8801_fullscan (1401, iCalibY, 100, 2, 400, resolution,
			HP3500_COLOR_SCAN, (rts8801_callback) storefunc, &cd,
			calib_info, iMoveFlags, -1, -1, -1, -1, 0, 0);
      DBG (30, "Completed scan for initial calibration pass\n");
      iMoveFlags = RTS8801_F_SUPPRESS_MOVEMENT | RTS8801_F_NO_DISPLACEMENTS;
      iCalibY = 2;
      for (i = 0; i < 6; ++i)
	{
	  int sum;
	  if (aiBestOffset[i] >= 255 || aiPassed[i] > 2)
	    continue;
	  sum = sum_channel (calibbuf + i, 50, 1);
	  DBG (20, "channel[%d] sum = %d (target %d)\n", i, sum,
	       iCalibTarget);
	  if (sum < iCalibTarget)
            {
              onechanged = 1;
              ++aiBestOffset[i];
            }
          else
            {
              ++aiPassed[i];
            }
	}
      DBG (30, "Initial calibration pass completed\n");
    }
  while (onechanged);
  DBG (20, "Offsets calculated\n");
  rt_turn_on_lamp();
  usleep(500000);
  tdetail_buffer =
    (unsigned char *) malloc (w * 3 * detailed_calibration_rows);
  for (i = 0; i < 3; ++i)
    {
      calib_info[i * 3 + 2] = 1;
      aiPassed[i] = 0;
    }
  do
    {
      struct dcalibdata dcdt;
      dcdt.buffers[0] = tdetail_buffer;
      dcdt.buffers[1] = (tdetail_buffer + w * detailed_calibration_rows);
      dcdt.buffers[2] = (dcdt.buffers[1] + w * detailed_calibration_rows);
      dcdt.pixelsperrow = w;
      dcdt.pixelnow = dcdt.channelnow = dcdt.firstrowdone = 0;
      DBG (20, "Scanning for part 2 of initial calibration\n");
      rts8801_fullscan (x, 4, w, detailed_calibration_rows + 1, resolution,
			resolution, HP3500_COLOR_SCAN,
			(rts8801_callback) accumfunc, &dcdt, calib_info,
			RTS8801_F_SUPPRESS_MOVEMENT | RTS8801_F_NO_DISPLACEMENTS, -1, -1, -1, -1, 0, 0);
      DBG (20, "Scan for part 2 of initial calibration completed\n");
      onechanged = 0;
      for (i = 0; i < 3; ++i)
	{
	  int largest = 1;
          if (aiPassed[i] > 2 || calib_info[i * 3 + 2] >= 63)
            continue;
 	  for (j = 0; j < w; ++j)
	    {
	      int val =
		calcmedian (dcdt.buffers[i], j, w, detailed_calibration_rows);
	      if (val > largest)
		largest = val;
	    }
	  if (largest < 0xe0)
            {
              ++calib_info[i * 3 + 2];
              onechanged = 1;
            }
          else
            {
              ++aiPassed[i];
            }
	}
    }
  while (onechanged);
  for (i = 0; i < 3; ++i)
    {
      DBG (10, "Channel [%d] gain=%02x  offset=%02x\n",
	   i, calib_info[i * 3] + 2, calib_info[i * 3]);
    }
  DBG (20, "Gain factors calculated\n");
  /* Stage 2 calibration */
  DBG (10, "Calibrating (stage 2)\n");
  detail_buffer =
    (unsigned char *) malloc (w * 3 * detailed_calibration_rows);
  dcd.buffers[0] = detail_buffer;
  dcd.buffers[1] = (detail_buffer + w * detailed_calibration_rows);
  dcd.buffers[2] = (dcd.buffers[1] + w * detailed_calibration_rows);
  dcd.pixelsperrow = w;
  /* And now for the detailed calibration */
  resolution_index = find_resolution_index (resolution);
  base_resolution = 300;
  if (resparms[resolution_index].cph0s)
    base_resolution *= 2;
  if (resparms[resolution_index].d3_bit_3_value)
    base_resolution *= 2;
  resolution_divisor = base_resolution / resolution;
  calibration_size = w * resolution_divisor * 6 + 1568 + 96;
  red_calibration_offset = 0x600;
  green_calibration_offset =
    red_calibration_offset + w * resolution_divisor * 2;
  blue_calibration_offset =
    green_calibration_offset + w * resolution_divisor * 2;
  end_calibration_offset =
    blue_calibration_offset + w * resolution_divisor * 2;
  pDetailedCalib = (unsigned char *) malloc (calibration_size);
  memset (pDetailedCalib, 0, calibration_size);
  for (i = 0; i < 3; ++i)
    {
      int idx =
        (i == 0) ? red_calibration_offset :
        (i == 1) ? green_calibration_offset :
                       blue_calibration_offset;
      for (j = 0; j < 256; j++)
        {
          /* Gamma table - appears to be 256 byte pairs for each input
           * range (so the first entry cover inputs in the range 0 to 1,
           * the second 1 to 2, and so on), mapping that input range
           * (including the fractional parts within it) to an output
           * range.
           */
          pDetailedCalib[i * 512 + j * 2] = j;
          pDetailedCalib[i * 512 + j * 2 + 1] = j;
        }
      for (j = 0; j < w; ++j)
        {
          for (k = 0; k < resolution_divisor; ++k)
            {
              pDetailedCalib[idx++] = 0;
              pDetailedCalib[idx++] = 0x80;
            }
        }
    }
  rt_set_sram_page (0);
  rt_set_one_register (0x93, r93setting);
  rt_write_sram (calibration_size, pDetailedCalib);
  postprocess_gains = (double *) malloc(sizeof(double) * 3 * w);
  postprocess_offsets = (double *) malloc(sizeof(double) * 3 * w);
  for (pass = 0; pass < DETAILED_PASS_COUNT; ++pass)
    {
      int ppidx = 0;
      DBG (10, "Performing detailed calibration scan %d\n", pass);
      switch (pass)
      {
      case DETAILED_PASS_OFFSETS:
        rt_turn_off_lamp();
	usleep(500000); /* To be sure it has gone off */
        break;
      case DETAILED_PASS_GAINS_FIRSTPASS:
        rt_turn_on_lamp();
	usleep(500000); /* Give the lamp time to settle */
        break;
      }
      dcd.pixelnow = dcd.channelnow = dcd.firstrowdone = 0;
      rts8801_fullscan (x, iCalibY, w, detailed_calibration_rows + 1,
                        resolution, resolution, HP3500_COLOR_SCAN,
                        (rts8801_callback) accumfunc, &dcd,
			calib_info,
                        RTS8801_F_SUPPRESS_MOVEMENT | RTS8801_F_NO_DISPLACEMENTS,
			red_calibration_offset,
			green_calibration_offset,
			blue_calibration_offset,
			end_calibration_offset,
			0, 0);
      DBG (10, " Detailed calibration scan %d completed\n", pass);
      for (i = 0; i < 3; ++i)
        {
          int idx =
            (i == 0) ? red_calibration_offset :
	    (i == 1) ? green_calibration_offset :
                       blue_calibration_offset;
          for (j = 0; j < w; ++j)
            {
              double multnow = 0x80;
              int offnow = 0;
              /* This seems to be the approach for reg 0x40 & 0x3f == 0x27, which allows detailed
               * calibration to return either higher or lower values.
               */
              {
                double denom1 =
                  calcmedian (dcd.buffers[i], j, w, detailed_calibration_rows);
		switch (pass)
                  {
                  case DETAILED_PASS_OFFSETS:
                    /* The offset is the number needed to be subtracted from "black" at detailed gain = 0x80,
                     * which is the value we started with. For the next round, pull the gain down to 0x20. Our
                     * next scan is a test scan to confirm the offset works.
                     */
                    multnow = 0x20;
                    offnow = denom1;
                    break;
                  case DETAILED_PASS_GAINS_FIRSTPASS:
                    multnow = 128.0 / denom1 * 0x20; /* Then bring it up to whatever we need to hit 192 */
                    if (multnow > 255)
                      multnow = 255;
                    offnow = pDetailedCalib[idx];
                    break;
                  case DETAILED_PASS_GAINS_SECONDPASS:
                    multnow = 255.0 / denom1 * contrast_adjust * pDetailedCalib[idx+1]; /* And finally to 255 */
                    offnow = pDetailedCalib[idx] - brightness_adjust * 0x80 / multnow;
                    if (offnow < 0)
                      {
                        postprocess_offsets[ppidx] = multnow * offnow / 0x80;
                        offnow = 0;
                        needs_postprocessed_calibration = 1;
                      }
                    else if (offnow > 255)
                      {
                        postprocess_offsets[ppidx] = multnow * (offnow - 255) / 0x80;
                        offnow = 255;
                        needs_postprocessed_calibration = 1;
                      }
                    else
                      {
                        postprocess_offsets[ppidx] = 0;
                      }
                    if (multnow > 255)
                      {
                        postprocess_gains[ppidx] = multnow / 255;
                        multnow = 255;
                        needs_postprocessed_calibration = 1;
                      }
                    else
                      {
                        postprocess_gains[ppidx] = 1.0;
                      }
                    break;
                  }
              }
              if (offnow > 255)
                offnow = 255;
              for (k = 0; k < resolution_divisor; ++k)
                {
                  pDetailedCalib[idx++] = offnow;         /* Subtract this value from the result  at gains = 0x80*/
                  pDetailedCalib[idx++] = multnow;        /* Then multiply by this value divided by 0x80	*/
                }
              ++ppidx;
            }
        }
      if (pass == DETAILED_PASS_GAINS_SECONDPASS)
        {
           /* Build gamma table */
           unsigned char *redgamma = pDetailedCalib;
           unsigned char *greengamma = redgamma + 512;
           unsigned char *bluegamma = greengamma + 512;
           double val;
	   double invgamma = 1.0l / gamma;
           *redgamma++ = *bluegamma++ = *greengamma++ = 0;
           /* The windows driver does a linear interpolation for the next 19 boundaries */
           val = pow (20.0l / 255, invgamma) * 255;
	   for (j = 1; j <= 20; ++j)
             {
               *redgamma++ = *bluegamma++ = *greengamma++ = val * j / 20 + 0.5;
               *redgamma++ = *bluegamma++ = *greengamma++ = val * j / 20 + 0.5;
             }
           for (; j <= 255; ++j)
             {
               val = pow((double) j / 255, invgamma) * 255;
               *redgamma++ = *bluegamma++ = *greengamma++ = val + 0.5;
               *redgamma++ = *bluegamma++ = *greengamma++ = val + 0.5;
             }
           *redgamma++ = *bluegamma++ = *greengamma++ = 255;
        }
      DBG (10, "\n");
      rt_set_sram_page (0);
      rt_set_one_register (0x93, r93setting);
      rt_write_sram (calibration_size, pDetailedCalib);
    }
  /* And finally, perform the scan */
  DBG (10, "Scanning\n");
  rts8801_rewind ();
  rts8801_fullscan (x, y, w, h, resolution, resolution, colour, cbfunc, param,
		    calib_info, 0,
		    red_calibration_offset, green_calibration_offset,
		    blue_calibration_offset, end_calibration_offset,
                    needs_postprocessed_calibration ? postprocess_offsets : 0,
                    needs_postprocessed_calibration ? postprocess_gains : 0);
  rt_turn_off_lamp ();
  rts8801_rewind ();
  rt_set_powersave_mode (1);
  if (pDetailedCalib)
    free (pDetailedCalib);
  if (detail_buffer)
    free (detail_buffer);
  if (tdetail_buffer)
    free(tdetail_buffer);
  if (postprocess_gains)
    free(postprocess_gains);
  if (postprocess_offsets)
    free(postprocess_offsets);
  return 0;
}
static int
writefunc (struct hp3500_write_info *winfo, int bytes, char *data)
{
  static int warned = 0;
  if (bytes > winfo->bytesleft)
    {
      if (!warned)
	{
	  warned = 1;
	  DBG (1, "Overflow protection triggered\n");
	  rt_stop_moving ();
	}
      bytes = winfo->bytesleft;
      if (!bytes)
	return 0;
    }
  winfo->bytesleft -= bytes;
  return write (winfo->scanner->pipe_w, data, bytes) == bytes;
}
#ifdef _POSIX_SOURCE
static void
sigtermHandler (int signal)
{
  signal = signal;		/* get rid of compiler warning */
  cancelled_scan = 1;
}
#endif
static int
reader_process (void *pv)
{
  struct hp3500_data *scanner = pv;
  time_t t;
  sigset_t ignore_set;
  sigset_t sigterm_set;
  struct SIGACTION act;
  struct hp3500_write_info winfo;
  int status;
  if (sanei_thread_is_forked ())
    {
      close (scanner->pipe_r);
      sigfillset (&ignore_set);
      sigdelset (&ignore_set, SIGTERM);
#if     defined (__APPLE__) && defined (__MACH__)
      sigdelset (&ignore_set, SIGUSR2);
#endif
      sigprocmask (SIG_SETMASK, &ignore_set, 0);
      sigemptyset (&sigterm_set);
      sigaddset (&sigterm_set, SIGTERM);
      memset (&act, 0, sizeof (act));
#ifdef     _POSIX_SOURCE
      act.sa_handler = sigtermHandler;
#endif
      sigaction (SIGTERM, &act, 0);
    }
  /* Warm up the lamp again if our last scan ended more than 5 minutes ago. */
  time (&t);
  do_warmup = (t - scanner->last_scan) > 300;
  if (getenv ("HP3500_NOWARMUP") && atoi (getenv ("HP3500_NOWARMUP")) > 0)
    do_warmup = 0;
  udh = scanner->sfd;
  cancelled_scan = 0;
  winfo.scanner = scanner;
  winfo.bytesleft =
    scanner->bytes_per_scan_line * scanner->scan_height_pixels;
  if (getenv ("HP3500_SLEEP"))
    {
      int seconds = atoi (getenv ("HP3500_SLEEP"));
      DBG (1, "Backend process %d sleeping for %d seconds\n", getpid (),
	   seconds);
      sleep (seconds);
    }
  DBG (10, "Scanning at %ddpi, mode=%s\n", scanner->resolution,
       scan_mode_list[scanner->mode]);
  if (rts8801_scan
      (scanner->actres_pixels.left + 250 * scanner->resolution / 1200,
       scanner->actres_pixels.top + 599 * scanner->resolution / 1200,
       scanner->actres_pixels.right - scanner->actres_pixels.left,
       scanner->actres_pixels.bottom - scanner->actres_pixels.top,
       scanner->resolution, scanner->mode, scanner->brightness,
       scanner->contrast, (rts8801_callback) writefunc, &winfo,
       scanner->gamma) >= 0)
    status = SANE_STATUS_GOOD;
  status = SANE_STATUS_IO_ERROR;
  close (scanner->pipe_w);
  return status;
}
static size_t
max_string_size (char const **strings)
{
  size_t size, max_size = 0;
  SANE_Int i;
  for (i = 0; strings[i]; ++i)
    {
      size = strlen (strings[i]) + 1;
      if (size > max_size)
	max_size = size;
    }
  return max_size;
}