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usbvideo.c

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/spinlock.h>

#include <asm/io.h>

#include "usbvideo.h"

#if defined(MAP_NR)
#define     virt_to_page(v)   MAP_NR(v)   /* Kernels 2.2.x */
#endif

static int video_nr = -1;
module_param(video_nr, int, 0);

/*
 * Local prototypes.
 */
static void usbvideo_Disconnect(struct usb_interface *intf);
static void usbvideo_CameraRelease(struct uvd *uvd);

static int usbvideo_v4l_ioctl(struct inode *inode, struct file *file,
                        unsigned int cmd, unsigned long arg);
static int usbvideo_v4l_mmap(struct file *file, struct vm_area_struct *vma);
static int usbvideo_v4l_open(struct inode *inode, struct file *file);
static ssize_t usbvideo_v4l_read(struct file *file, char __user *buf,
                       size_t count, loff_t *ppos);
static int usbvideo_v4l_close(struct inode *inode, struct file *file);

static int usbvideo_StartDataPump(struct uvd *uvd);
static void usbvideo_StopDataPump(struct uvd *uvd);
static int usbvideo_GetFrame(struct uvd *uvd, int frameNum);
static int usbvideo_NewFrame(struct uvd *uvd, int framenum);
static void usbvideo_SoftwareContrastAdjustment(struct uvd *uvd,
                                    struct usbvideo_frame *frame);

/*******************************/
/* Memory management functions */
/*******************************/
static void *usbvideo_rvmalloc(unsigned long size)
{
      void *mem;
      unsigned long adr;

      size = PAGE_ALIGN(size);
      mem = vmalloc_32(size);
      if (!mem)
            return NULL;

      memset(mem, 0, size); /* Clear the ram out, no junk to the user */
      adr = (unsigned long) mem;
      while (size > 0) {
            SetPageReserved(vmalloc_to_page((void *)adr));
            adr += PAGE_SIZE;
            size -= PAGE_SIZE;
      }

      return mem;
}

static void usbvideo_rvfree(void *mem, unsigned long size)
{
      unsigned long adr;

      if (!mem)
            return;

      adr = (unsigned long) mem;
      while ((long) size > 0) {
            ClearPageReserved(vmalloc_to_page((void *)adr));
            adr += PAGE_SIZE;
            size -= PAGE_SIZE;
      }
      vfree(mem);
}

static void RingQueue_Initialize(struct RingQueue *rq)
{
      assert(rq != NULL);
      init_waitqueue_head(&rq->wqh);
}

static void RingQueue_Allocate(struct RingQueue *rq, int rqLen)
{
      /* Make sure the requested size is a power of 2 and
         round up if necessary. This allows index wrapping
         using masks rather than modulo */

      int i = 1;
      assert(rq != NULL);
      assert(rqLen > 0);

      while(rqLen >> i)
            i++;
      if(rqLen != 1 << (i-1))
            rqLen = 1 << i;

      rq->length = rqLen;
      rq->ri = rq->wi = 0;
      rq->queue = usbvideo_rvmalloc(rq->length);
      assert(rq->queue != NULL);
}

static int RingQueue_IsAllocated(const struct RingQueue *rq)
{
      if (rq == NULL)
            return 0;
      return (rq->queue != NULL) && (rq->length > 0);
}

static void RingQueue_Free(struct RingQueue *rq)
{
      assert(rq != NULL);
      if (RingQueue_IsAllocated(rq)) {
            usbvideo_rvfree(rq->queue, rq->length);
            rq->queue = NULL;
            rq->length = 0;
      }
}

int RingQueue_Dequeue(struct RingQueue *rq, unsigned char *dst, int len)
{
      int rql, toread;

      assert(rq != NULL);
      assert(dst != NULL);

      rql = RingQueue_GetLength(rq);
      if(!rql)
            return 0;

      /* Clip requested length to available data */
      if(len > rql)
            len = rql;

      toread = len;
      if(rq->ri > rq->wi) {
            /* Read data from tail */
            int read = (toread < (rq->length - rq->ri)) ? toread : rq->length - rq->ri;
            memcpy(dst, rq->queue + rq->ri, read);
            toread -= read;
            dst += read;
            rq->ri = (rq->ri + read) & (rq->length-1);
      }
      if(toread) {
            /* Read data from head */
            memcpy(dst, rq->queue + rq->ri, toread);
            rq->ri = (rq->ri + toread) & (rq->length-1);
      }
      return len;
}

EXPORT_SYMBOL(RingQueue_Dequeue);

int RingQueue_Enqueue(struct RingQueue *rq, const unsigned char *cdata, int n)
{
      int enqueued = 0;

      assert(rq != NULL);
      assert(cdata != NULL);
      assert(rq->length > 0);
      while (n > 0) {
            int m, q_avail;

            /* Calculate the largest chunk that fits the tail of the ring */
            q_avail = rq->length - rq->wi;
            if (q_avail <= 0) {
                  rq->wi = 0;
                  q_avail = rq->length;
            }
            m = n;
            assert(q_avail > 0);
            if (m > q_avail)
                  m = q_avail;

            memcpy(rq->queue + rq->wi, cdata, m);
            RING_QUEUE_ADVANCE_INDEX(rq, wi, m);
            cdata += m;
            enqueued += m;
            n -= m;
      }
      return enqueued;
}

EXPORT_SYMBOL(RingQueue_Enqueue);

static void RingQueue_InterruptibleSleepOn(struct RingQueue *rq)
{
      assert(rq != NULL);
      interruptible_sleep_on(&rq->wqh);
}

void RingQueue_WakeUpInterruptible(struct RingQueue *rq)
{
      assert(rq != NULL);
      if (waitqueue_active(&rq->wqh))
            wake_up_interruptible(&rq->wqh);
}

EXPORT_SYMBOL(RingQueue_WakeUpInterruptible);

void RingQueue_Flush(struct RingQueue *rq)
{
      assert(rq != NULL);
      rq->ri = 0;
      rq->wi = 0;
}

EXPORT_SYMBOL(RingQueue_Flush);


/*
 * usbvideo_VideosizeToString()
 *
 * This procedure converts given videosize value to readable string.
 *
 * History:
 * 07-Aug-2000 Created.
 * 19-Oct-2000 Reworked for usbvideo module.
 */
static void usbvideo_VideosizeToString(char *buf, int bufLen, videosize_t vs)
{
      char tmp[40];
      int n;

      n = 1 + sprintf(tmp, "%ldx%ld", VIDEOSIZE_X(vs), VIDEOSIZE_Y(vs));
      assert(n < sizeof(tmp));
      if ((buf == NULL) || (bufLen < n))
            err("usbvideo_VideosizeToString: buffer is too small.");
      else
            memmove(buf, tmp, n);
}

/*
 * usbvideo_OverlayChar()
 *
 * History:
 * 01-Feb-2000 Created.
 */
static void usbvideo_OverlayChar(struct uvd *uvd, struct usbvideo_frame *frame,
                         int x, int y, int ch)
{
      static const unsigned short digits[16] = {
            0xF6DE, /* 0 */
            0x2492, /* 1 */
            0xE7CE, /* 2 */
            0xE79E, /* 3 */
            0xB792, /* 4 */
            0xF39E, /* 5 */
            0xF3DE, /* 6 */
            0xF492, /* 7 */
            0xF7DE, /* 8 */
            0xF79E, /* 9 */
            0x77DA, /* a */
            0xD75C, /* b */
            0xF24E, /* c */
            0xD6DC, /* d */
            0xF34E, /* e */
            0xF348  /* f */
      };
      unsigned short digit;
      int ix, iy;

      if ((uvd == NULL) || (frame == NULL))
            return;

      if (ch >= '0' && ch <= '9')
            ch -= '0';
      else if (ch >= 'A' && ch <= 'F')
            ch = 10 + (ch - 'A');
      else if (ch >= 'a' && ch <= 'f')
            ch = 10 + (ch - 'a');
      else
            return;
      digit = digits[ch];

      for (iy=0; iy < 5; iy++) {
            for (ix=0; ix < 3; ix++) {
                  if (digit & 0x8000) {
                        if (uvd->paletteBits & (1L << VIDEO_PALETTE_RGB24)) {
/* TODO */                    RGB24_PUTPIXEL(frame, x+ix, y+iy, 0xFF, 0xFF, 0xFF);
                        }
                  }
                  digit = digit << 1;
            }
      }
}

/*
 * usbvideo_OverlayString()
 *
 * History:
 * 01-Feb-2000 Created.
 */
static void usbvideo_OverlayString(struct uvd *uvd, struct usbvideo_frame *frame,
                           int x, int y, const char *str)
{
      while (*str) {
            usbvideo_OverlayChar(uvd, frame, x, y, *str);
            str++;
            x += 4; /* 3 pixels character + 1 space */
      }
}

/*
 * usbvideo_OverlayStats()
 *
 * Overlays important debugging information.
 *
 * History:
 * 01-Feb-2000 Created.
 */
static void usbvideo_OverlayStats(struct uvd *uvd, struct usbvideo_frame *frame)
{
      const int y_diff = 8;
      char tmp[16];
      int x = 10, y=10;
      long i, j, barLength;
      const int qi_x1 = 60, qi_y1 = 10;
      const int qi_x2 = VIDEOSIZE_X(frame->request) - 10, qi_h = 10;

      /* Call the user callback, see if we may proceed after that */
      if (VALID_CALLBACK(uvd, overlayHook)) {
            if (GET_CALLBACK(uvd, overlayHook)(uvd, frame) < 0)
                  return;
      }

      /*
       * We draw a (mostly) hollow rectangle with qi_xxx coordinates.
       * Left edge symbolizes the queue index 0; right edge symbolizes
       * the full capacity of the queue.
       */
      barLength = qi_x2 - qi_x1 - 2;
      if ((barLength > 10) && (uvd->paletteBits & (1L << VIDEO_PALETTE_RGB24))) {
/* TODO */  long u_lo, u_hi, q_used;
            long m_ri, m_wi, m_lo, m_hi;

            /*
             * Determine fill zones (used areas of the queue):
             * 0 xxxxxxx u_lo ...... uvd->dp.ri xxxxxxxx u_hi ..... uvd->dp.length
             *
             * if u_lo < 0 then there is no first filler.
             */

            q_used = RingQueue_GetLength(&uvd->dp);
            if ((uvd->dp.ri + q_used) >= uvd->dp.length) {
                  u_hi = uvd->dp.length;
                  u_lo = (q_used + uvd->dp.ri) & (uvd->dp.length-1);
            } else {
                  u_hi = (q_used + uvd->dp.ri);
                  u_lo = -1;
            }

            /* Convert byte indices into screen units */
            m_ri = qi_x1 + ((barLength * uvd->dp.ri) / uvd->dp.length);
            m_wi = qi_x1 + ((barLength * uvd->dp.wi) / uvd->dp.length);
            m_lo = (u_lo > 0) ? (qi_x1 + ((barLength * u_lo) / uvd->dp.length)) : -1;
            m_hi = qi_x1 + ((barLength * u_hi) / uvd->dp.length);

            for (j=qi_y1; j < (qi_y1 + qi_h); j++) {
                  for (i=qi_x1; i < qi_x2; i++) {
                        /* Draw border lines */
                        if ((j == qi_y1) || (j == (qi_y1 + qi_h - 1)) ||
                            (i == qi_x1) || (i == (qi_x2 - 1))) {
                              RGB24_PUTPIXEL(frame, i, j, 0xFF, 0xFF, 0xFF);
                              continue;
                        }
                        /* For all other points the Y coordinate does not matter */
                        if ((i >= m_ri) && (i <= (m_ri + 3))) {
                              RGB24_PUTPIXEL(frame, i, j, 0x00, 0xFF, 0x00);
                        } else if ((i >= m_wi) && (i <= (m_wi + 3))) {
                              RGB24_PUTPIXEL(frame, i, j, 0xFF, 0x00, 0x00);
                        } else if ((i < m_lo) || ((i > m_ri) && (i < m_hi)))
                              RGB24_PUTPIXEL(frame, i, j, 0x00, 0x00, 0xFF);
                  }
            }
      }

      sprintf(tmp, "%8lx", uvd->stats.frame_num);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8lx", uvd->stats.urb_count);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8lx", uvd->stats.urb_length);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8lx", uvd->stats.data_count);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8lx", uvd->stats.header_count);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8lx", uvd->stats.iso_skip_count);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8lx", uvd->stats.iso_err_count);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8x", uvd->vpic.colour);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8x", uvd->vpic.hue);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8x", uvd->vpic.brightness >> 8);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8x", uvd->vpic.contrast >> 12);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;

      sprintf(tmp, "%8d", uvd->vpic.whiteness >> 8);
      usbvideo_OverlayString(uvd, frame, x, y, tmp);
      y += y_diff;
}

/*
 * usbvideo_ReportStatistics()
 *
 * This procedure prints packet and transfer statistics.
 *
 * History:
 * 14-Jan-2000 Corrected default multiplier.
 */
static void usbvideo_ReportStatistics(const struct uvd *uvd)
{
      if ((uvd != NULL) && (uvd->stats.urb_count > 0)) {
            unsigned long allPackets, badPackets, goodPackets, percent;
            allPackets = uvd->stats.urb_count * CAMERA_URB_FRAMES;
            badPackets = uvd->stats.iso_skip_count + uvd->stats.iso_err_count;
            goodPackets = allPackets - badPackets;
            /* Calculate percentage wisely, remember integer limits */
            assert(allPackets != 0);
            if (goodPackets < (((unsigned long)-1)/100))
                  percent = (100 * goodPackets) / allPackets;
            else
                  percent = goodPackets / (allPackets / 100);
            info("Packet Statistics: Total=%lu. Empty=%lu. Usage=%lu%%",
                 allPackets, badPackets, percent);
            if (uvd->iso_packet_len > 0) {
                  unsigned long allBytes, xferBytes;
                  char multiplier = ' ';
                  allBytes = allPackets * uvd->iso_packet_len;
                  xferBytes = uvd->stats.data_count;
                  assert(allBytes != 0);
                  if (xferBytes < (((unsigned long)-1)/100))
                        percent = (100 * xferBytes) / allBytes;
                  else
                        percent = xferBytes / (allBytes / 100);
                  /* Scale xferBytes for easy reading */
                  if (xferBytes > 10*1024) {
                        xferBytes /= 1024;
                        multiplier = 'K';
                        if (xferBytes > 10*1024) {
                              xferBytes /= 1024;
                              multiplier = 'M';
                              if (xferBytes > 10*1024) {
                                    xferBytes /= 1024;
                                    multiplier = 'G';
                                    if (xferBytes > 10*1024) {
                                          xferBytes /= 1024;
                                          multiplier = 'T';
                                    }
                              }
                        }
                  }
                  info("Transfer Statistics: Transferred=%lu%cB Usage=%lu%%",
                       xferBytes, multiplier, percent);
            }
      }
}

/*
 * usbvideo_TestPattern()
 *
 * Procedure forms a test pattern (yellow grid on blue background).
 *
 * Parameters:
 * fullframe: if TRUE then entire frame is filled, otherwise the procedure
 *          continues from the current scanline.
 * pmode      0: fill the frame with solid blue color (like on VCR or TV)
 *          1: Draw a colored grid
 *
 * History:
 * 01-Feb-2000 Created.
 */
void usbvideo_TestPattern(struct uvd *uvd, int fullframe, int pmode)
{
      struct usbvideo_frame *frame;
      int num_cell = 0;
      int scan_length = 0;
      static int num_pass = 0;

      if (uvd == NULL) {
            err("%s: uvd == NULL", __FUNCTION__);
            return;
      }
      if ((uvd->curframe < 0) || (uvd->curframe >= USBVIDEO_NUMFRAMES)) {
            err("%s: uvd->curframe=%d.", __FUNCTION__, uvd->curframe);
            return;
      }

      /* Grab the current frame */
      frame = &uvd->frame[uvd->curframe];

      /* Optionally start at the beginning */
      if (fullframe) {
            frame->curline = 0;
            frame->seqRead_Length = 0;
      }
#if 0
      {     /* For debugging purposes only */
            char tmp[20];
            usbvideo_VideosizeToString(tmp, sizeof(tmp), frame->request);
            info("testpattern: frame=%s", tmp);
      }
#endif
      /* Form every scan line */
      for (; frame->curline < VIDEOSIZE_Y(frame->request); frame->curline++) {
            int i;
            unsigned char *f = frame->data +
                  (VIDEOSIZE_X(frame->request) * V4L_BYTES_PER_PIXEL * frame->curline);
            for (i=0; i < VIDEOSIZE_X(frame->request); i++) {
                  unsigned char cb=0x80;
                  unsigned char cg = 0;
                  unsigned char cr = 0;

                  if (pmode == 1) {
                        if (frame->curline % 32 == 0)
                              cb = 0, cg = cr = 0xFF;
                        else if (i % 32 == 0) {
                              if (frame->curline % 32 == 1)
                                    num_cell++;
                              cb = 0, cg = cr = 0xFF;
                        } else {
                              cb = ((num_cell*7) + num_pass) & 0xFF;
                              cg = ((num_cell*5) + num_pass*2) & 0xFF;
                              cr = ((num_cell*3) + num_pass*3) & 0xFF;
                        }
                  } else {
                        /* Just the blue screen */
                  }

                  *f++ = cb;
                  *f++ = cg;
                  *f++ = cr;
                  scan_length += 3;
            }
      }

      frame->frameState = FrameState_Done;
      frame->seqRead_Length += scan_length;
      ++num_pass;

      /* We do this unconditionally, regardless of FLAGS_OVERLAY_STATS */
      usbvideo_OverlayStats(uvd, frame);
}

EXPORT_SYMBOL(usbvideo_TestPattern);


#ifdef DEBUG
/*
 * usbvideo_HexDump()
 *
 * A debugging tool. Prints hex dumps.
 *
 * History:
 * 29-Jul-2000 Added printing of offsets.
 */
void usbvideo_HexDump(const unsigned char *data, int len)
{
      const int bytes_per_line = 32;
      char tmp[128]; /* 32*3 + 5 */
      int i, k;

      for (i=k=0; len > 0; i++, len--) {
            if (i > 0 && ((i % bytes_per_line) == 0)) {
                  printk("%s\n", tmp);
                  k=0;
            }
            if ((i % bytes_per_line) == 0)
                  k += sprintf(&tmp[k], "%04x: ", i);
            k += sprintf(&tmp[k], "%02x ", data[i]);
      }
      if (k > 0)
            printk("%s\n", tmp);
}

EXPORT_SYMBOL(usbvideo_HexDump);

#endif

/* ******************************************************************** */

/* XXX: this piece of crap really wants some error handling.. */
static void usbvideo_ClientIncModCount(struct uvd *uvd)
{
      if (uvd == NULL) {
            err("%s: uvd == NULL", __FUNCTION__);
            return;
      }
      if (uvd->handle == NULL) {
            err("%s: uvd->handle == NULL", __FUNCTION__);
            return;
      }
      if (uvd->handle->md_module == NULL) {
            err("%s: uvd->handle->md_module == NULL", __FUNCTION__);
            return;
      }
      if (!try_module_get(uvd->handle->md_module)) {
            err("%s: try_module_get() == 0", __FUNCTION__);
            return;
      }
}

static void usbvideo_ClientDecModCount(struct uvd *uvd)
{
      if (uvd == NULL) {
            err("%s: uvd == NULL", __FUNCTION__);
            return;
      }
      if (uvd->handle == NULL) {
            err("%s: uvd->handle == NULL", __FUNCTION__);
            return;
      }
      if (uvd->handle->md_module == NULL) {
            err("%s: uvd->handle->md_module == NULL", __FUNCTION__);
            return;
      }
      module_put(uvd->handle->md_module);
}

int usbvideo_register(
      struct usbvideo **pCams,
      const int num_cams,
      const int num_extra,
      const char *driverName,
      const struct usbvideo_cb *cbTbl,
      struct module *md,
      const struct usb_device_id *id_table)
{
      struct usbvideo *cams;
      int i, base_size, result;

      /* Check parameters for sanity */
      if ((num_cams <= 0) || (pCams == NULL) || (cbTbl == NULL)) {
            err("%s: Illegal call", __FUNCTION__);
            return -EINVAL;
      }

      /* Check registration callback - must be set! */
      if (cbTbl->probe == NULL) {
            err("%s: probe() is required!", __FUNCTION__);
            return -EINVAL;
      }

      base_size = num_cams * sizeof(struct uvd) + sizeof(struct usbvideo);
      cams = (struct usbvideo *) kzalloc(base_size, GFP_KERNEL);
      if (cams == NULL) {
            err("Failed to allocate %d. bytes for usbvideo struct", base_size);
            return -ENOMEM;
      }
      dbg("%s: Allocated $%p (%d. bytes) for %d. cameras",
          __FUNCTION__, cams, base_size, num_cams);

      /* Copy callbacks, apply defaults for those that are not set */
      memmove(&cams->cb, cbTbl, sizeof(cams->cb));
      if (cams->cb.getFrame == NULL)
            cams->cb.getFrame = usbvideo_GetFrame;
      if (cams->cb.disconnect == NULL)
            cams->cb.disconnect = usbvideo_Disconnect;
      if (cams->cb.startDataPump == NULL)
            cams->cb.startDataPump = usbvideo_StartDataPump;
      if (cams->cb.stopDataPump == NULL)
            cams->cb.stopDataPump = usbvideo_StopDataPump;

      cams->num_cameras = num_cams;
      cams->cam = (struct uvd *) &cams[1];
      cams->md_module = md;
      if (cams->md_module == NULL)
            warn("%s: module == NULL!", __FUNCTION__);
      mutex_init(&cams->lock);      /* to 1 == available */

      for (i = 0; i < num_cams; i++) {
            struct uvd *up = &cams->cam[i];

            up->handle = cams;

            /* Allocate user_data separately because of kmalloc's limits */
            if (num_extra > 0) {
                  up->user_size = num_cams * num_extra;
                  up->user_data = kmalloc(up->user_size, GFP_KERNEL);
                  if (up->user_data == NULL) {
                        err("%s: Failed to allocate user_data (%d. bytes)",
                            __FUNCTION__, up->user_size);
                        while (i) {
                              up = &cams->cam[--i];
                              kfree(up->user_data);
                        }
                        kfree(cams);
                        return -ENOMEM;
                  }
                  dbg("%s: Allocated cams[%d].user_data=$%p (%d. bytes)",
                       __FUNCTION__, i, up->user_data, up->user_size);
            }
      }

      /*
       * Register ourselves with USB stack.
       */
      strcpy(cams->drvName, (driverName != NULL) ? driverName : "Unknown");
      cams->usbdrv.name = cams->drvName;
      cams->usbdrv.probe = cams->cb.probe;
      cams->usbdrv.disconnect = cams->cb.disconnect;
      cams->usbdrv.id_table = id_table;

      /*
       * Update global handle to usbvideo. This is very important
       * because probe() can be called before usb_register() returns.
       * If the handle is not yet updated then the probe() will fail.
       */
      *pCams = cams;
      result = usb_register(&cams->usbdrv);
      if (result) {
            for (i = 0; i < num_cams; i++) {
                  struct uvd *up = &cams->cam[i];
                  kfree(up->user_data);
            }
            kfree(cams);
      }

      return result;
}

EXPORT_SYMBOL(usbvideo_register);

/*
 * usbvideo_Deregister()
 *
 * Procedure frees all usbvideo and user data structures. Be warned that
 * if you had some dynamically allocated components in ->user field then
 * you should free them before calling here.
 */
void usbvideo_Deregister(struct usbvideo **pCams)
{
      struct usbvideo *cams;
      int i;

      if (pCams == NULL) {
            err("%s: pCams == NULL", __FUNCTION__);
            return;
      }
      cams = *pCams;
      if (cams == NULL) {
            err("%s: cams == NULL", __FUNCTION__);
            return;
      }

      dbg("%s: Deregistering %s driver.", __FUNCTION__, cams->drvName);
      usb_deregister(&cams->usbdrv);

      dbg("%s: Deallocating cams=$%p (%d. cameras)", __FUNCTION__, cams, cams->num_cameras);
      for (i=0; i < cams->num_cameras; i++) {
            struct uvd *up = &cams->cam[i];
            int warning = 0;

            if (up->user_data != NULL) {
                  if (up->user_size <= 0)
                        ++warning;
            } else {
                  if (up->user_size > 0)
                        ++warning;
            }
            if (warning) {
                  err("%s: Warning: user_data=$%p user_size=%d.",
                      __FUNCTION__, up->user_data, up->user_size);
            } else {
                  dbg("%s: Freeing %d. $%p->user_data=$%p",
                      __FUNCTION__, i, up, up->user_data);
                  kfree(up->user_data);
            }
      }
      /* Whole array was allocated in one chunk */
      dbg("%s: Freed %d uvd structures",
          __FUNCTION__, cams->num_cameras);
      kfree(cams);
      *pCams = NULL;
}

EXPORT_SYMBOL(usbvideo_Deregister);

/*
 * usbvideo_Disconnect()
 *
 * This procedure stops all driver activity. Deallocation of
 * the interface-private structure (pointed by 'ptr') is done now
 * (if we don't have any open files) or later, when those files
 * are closed. After that driver should be removable.
 *
 * This code handles surprise removal. The uvd->user is a counter which
 * increments on open() and decrements on close(). If we see here that
 * this counter is not 0 then we have a client who still has us opened.
 * We set uvd->remove_pending flag as early as possible, and after that
 * all access to the camera will gracefully fail. These failures should
 * prompt client to (eventually) close the video device, and then - in
 * usbvideo_v4l_close() - we decrement uvd->uvd_used and usage counter.
 *
 * History:
 * 22-Jan-2000 Added polling of MOD_IN_USE to delay removal until all users gone.
 * 27-Jan-2000 Reworked to allow pending disconnects; see xxx_close()
 * 24-May-2000 Corrected to prevent race condition (MOD_xxx_USE_COUNT).
 * 19-Oct-2000 Moved to usbvideo module.
 */
static void usbvideo_Disconnect(struct usb_interface *intf)
{
      struct uvd *uvd = usb_get_intfdata (intf);
      int i;

      if (uvd == NULL) {
            err("%s($%p): Illegal call.", __FUNCTION__, intf);
            return;
      }

      usb_set_intfdata (intf, NULL);

      usbvideo_ClientIncModCount(uvd);
      if (uvd->debug > 0)
            info("%s(%p.)", __FUNCTION__, intf);

      mutex_lock(&uvd->lock);
      uvd->remove_pending = 1; /* Now all ISO data will be ignored */

      /* At this time we ask to cancel outstanding URBs */
      GET_CALLBACK(uvd, stopDataPump)(uvd);

      for (i=0; i < USBVIDEO_NUMSBUF; i++)
            usb_free_urb(uvd->sbuf[i].urb);

      usb_put_dev(uvd->dev);
      uvd->dev = NULL;            /* USB device is no more */

      video_unregister_device(&uvd->vdev);
      if (uvd->debug > 0)
            info("%s: Video unregistered.", __FUNCTION__);

      if (uvd->user)
            info("%s: In use, disconnect pending.", __FUNCTION__);
      else
            usbvideo_CameraRelease(uvd);
      mutex_unlock(&uvd->lock);
      info("USB camera disconnected.");

      usbvideo_ClientDecModCount(uvd);
}

/*
 * usbvideo_CameraRelease()
 *
 * This code does final release of uvd. This happens
 * after the device is disconnected -and- all clients
 * closed their files.
 *
 * History:
 * 27-Jan-2000 Created.
 */
static void usbvideo_CameraRelease(struct uvd *uvd)
{
      if (uvd == NULL) {
            err("%s: Illegal call", __FUNCTION__);
            return;
      }

      RingQueue_Free(&uvd->dp);
      if (VALID_CALLBACK(uvd, userFree))
            GET_CALLBACK(uvd, userFree)(uvd);
      uvd->uvd_used = 0;      /* This is atomic, no need to take mutex */
}

/*
 * usbvideo_find_struct()
 *
 * This code searches the array of preallocated (static) structures
 * and returns index of the first one that isn't in use. Returns -1
 * if there are no free structures.
 *
 * History:
 * 27-Jan-2000 Created.
 */
static int usbvideo_find_struct(struct usbvideo *cams)
{
      int u, rv = -1;

      if (cams == NULL) {
            err("No usbvideo handle?");
            return -1;
      }
      mutex_lock(&cams->lock);
      for (u = 0; u < cams->num_cameras; u++) {
            struct uvd *uvd = &cams->cam[u];
            if (!uvd->uvd_used) /* This one is free */
            {
                  uvd->uvd_used = 1;      /* In use now */
                  mutex_init(&uvd->lock); /* to 1 == available */
                  uvd->dev = NULL;
                  rv = u;
                  break;
            }
      }
      mutex_unlock(&cams->lock);
      return rv;
}

static struct file_operations usbvideo_fops = {
      .owner =  THIS_MODULE,
      .open =   usbvideo_v4l_open,
      .release =usbvideo_v4l_close,
      .read =   usbvideo_v4l_read,
      .mmap =   usbvideo_v4l_mmap,
      .ioctl =  usbvideo_v4l_ioctl,
      .compat_ioctl = v4l_compat_ioctl32,
      .llseek = no_llseek,
};
static const struct video_device usbvideo_template = {
      .owner =      THIS_MODULE,
      .type =       VID_TYPE_CAPTURE,
      .hardware =   VID_HARDWARE_CPIA,
      .fops =       &usbvideo_fops,
};

struct uvd *usbvideo_AllocateDevice(struct usbvideo *cams)
{
      int i, devnum;
      struct uvd *uvd = NULL;

      if (cams == NULL) {
            err("No usbvideo handle?");
            return NULL;
      }

      devnum = usbvideo_find_struct(cams);
      if (devnum == -1) {
            err("IBM USB camera driver: Too many devices!");
            return NULL;
      }
      uvd = &cams->cam[devnum];
      dbg("Device entry #%d. at $%p", devnum, uvd);

      /* Not relying upon caller we increase module counter ourselves */
      usbvideo_ClientIncModCount(uvd);

      mutex_lock(&uvd->lock);
      for (i=0; i < USBVIDEO_NUMSBUF; i++) {
            uvd->sbuf[i].urb = usb_alloc_urb(FRAMES_PER_DESC, GFP_KERNEL);
            if (uvd->sbuf[i].urb == NULL) {
                  err("usb_alloc_urb(%d.) failed.", FRAMES_PER_DESC);
                  uvd->uvd_used = 0;
                  uvd = NULL;
                  goto allocate_done;
            }
      }
      uvd->user=0;
      uvd->remove_pending = 0;
      uvd->last_error = 0;
      RingQueue_Initialize(&uvd->dp);

      /* Initialize video device structure */
      uvd->vdev = usbvideo_template;
      sprintf(uvd->vdev.name, "%.20s USB Camera", cams->drvName);
      /*
       * The client is free to overwrite those because we
       * return control to the client's probe function right now.
       */
allocate_done:
      mutex_unlock(&uvd->lock);
      usbvideo_ClientDecModCount(uvd);
      return uvd;
}

EXPORT_SYMBOL(usbvideo_AllocateDevice);

int usbvideo_RegisterVideoDevice(struct uvd *uvd)
{
      char tmp1[20], tmp2[20];      /* Buffers for printing */

      if (uvd == NULL) {
            err("%s: Illegal call.", __FUNCTION__);
            return -EINVAL;
      }
      if (uvd->video_endp == 0) {
            info("%s: No video endpoint specified; data pump disabled.", __FUNCTION__);
      }
      if (uvd->paletteBits == 0) {
            err("%s: No palettes specified!", __FUNCTION__);
            return -EINVAL;
      }
      if (uvd->defaultPalette == 0) {
            info("%s: No default palette!", __FUNCTION__);
      }

      uvd->max_frame_size = VIDEOSIZE_X(uvd->canvas) *
            VIDEOSIZE_Y(uvd->canvas) * V4L_BYTES_PER_PIXEL;
      usbvideo_VideosizeToString(tmp1, sizeof(tmp1), uvd->videosize);
      usbvideo_VideosizeToString(tmp2, sizeof(tmp2), uvd->canvas);

      if (uvd->debug > 0) {
            info("%s: iface=%d. endpoint=$%02x paletteBits=$%08lx",
                 __FUNCTION__, uvd->iface, uvd->video_endp, uvd->paletteBits);
      }
      if (video_register_device(&uvd->vdev, VFL_TYPE_GRABBER, video_nr) == -1) {
            err("%s: video_register_device failed", __FUNCTION__);
            return -EPIPE;
      }
      if (uvd->debug > 1) {
            info("%s: video_register_device() successful", __FUNCTION__);
      }
      if (uvd->dev == NULL) {
            err("%s: uvd->dev == NULL", __FUNCTION__);
            return -EINVAL;
      }

      info("%s on /dev/video%d: canvas=%s videosize=%s",
           (uvd->handle != NULL) ? uvd->handle->drvName : "???",
           uvd->vdev.minor, tmp2, tmp1);

      usb_get_dev(uvd->dev);
      return 0;
}

EXPORT_SYMBOL(usbvideo_RegisterVideoDevice);

/* ******************************************************************** */

static int usbvideo_v4l_mmap(struct file *file, struct vm_area_struct *vma)
{
      struct uvd *uvd = file->private_data;
      unsigned long start = vma->vm_start;
      unsigned long size  = vma->vm_end-vma->vm_start;
      unsigned long page, pos;

      if (!CAMERA_IS_OPERATIONAL(uvd))
            return -EFAULT;

      if (size > (((USBVIDEO_NUMFRAMES * uvd->max_frame_size) + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1)))
            return -EINVAL;

      pos = (unsigned long) uvd->fbuf;
      while (size > 0) {
            page = vmalloc_to_pfn((void *)pos);
            if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
                  return -EAGAIN;

            start += PAGE_SIZE;
            pos += PAGE_SIZE;
            if (size > PAGE_SIZE)
                  size -= PAGE_SIZE;
            else
                  size = 0;
      }

      return 0;
}

/*
 * usbvideo_v4l_open()
 *
 * This is part of Video 4 Linux API. The driver can be opened by one
 * client only (checks internal counter 'uvdser'). The procedure
 * then allocates buffers needed for video processing.
 *
 * History:
 * 22-Jan-2000 Rewrote, moved scratch buffer allocation here. Now the
 *             camera is also initialized here (once per connect), at
 *             expense of V4L client (it waits on open() call).
 * 27-Jan-2000 Used USBVIDEO_NUMSBUF as number of URB buffers.
 * 24-May-2000 Corrected to prevent race condition (MOD_xxx_USE_COUNT).
 */
static int usbvideo_v4l_open(struct inode *inode, struct file *file)
{
      struct video_device *dev = video_devdata(file);
      struct uvd *uvd = (struct uvd *) dev;
      const int sb_size = FRAMES_PER_DESC * uvd->iso_packet_len;
      int i, errCode = 0;

      if (uvd->debug > 1)
            info("%s($%p)", __FUNCTION__, dev);

      usbvideo_ClientIncModCount(uvd);
      mutex_lock(&uvd->lock);

      if (uvd->user) {
            err("%s: Someone tried to open an already opened device!", __FUNCTION__);
            errCode = -EBUSY;
      } else {
            /* Clear statistics */
            memset(&uvd->stats, 0, sizeof(uvd->stats));

            /* Clean pointers so we know if we allocated something */
            for (i=0; i < USBVIDEO_NUMSBUF; i++)
                  uvd->sbuf[i].data = NULL;

            /* Allocate memory for the frame buffers */
            uvd->fbuf_size = USBVIDEO_NUMFRAMES * uvd->max_frame_size;
            uvd->fbuf = usbvideo_rvmalloc(uvd->fbuf_size);
            RingQueue_Allocate(&uvd->dp, RING_QUEUE_SIZE);
            if ((uvd->fbuf == NULL) ||
                (!RingQueue_IsAllocated(&uvd->dp))) {
                  err("%s: Failed to allocate fbuf or dp", __FUNCTION__);
                  errCode = -ENOMEM;
            } else {
                  /* Allocate all buffers */
                  for (i=0; i < USBVIDEO_NUMFRAMES; i++) {
                        uvd->frame[i].frameState = FrameState_Unused;
                        uvd->frame[i].data = uvd->fbuf + i*(uvd->max_frame_size);
                        /*
                         * Set default sizes in case IOCTL (VIDIOCMCAPTURE)
                         * is not used (using read() instead).
                         */
                        uvd->frame[i].canvas = uvd->canvas;
                        uvd->frame[i].seqRead_Index = 0;
                  }
                  for (i=0; i < USBVIDEO_NUMSBUF; i++) {
                        uvd->sbuf[i].data = kmalloc(sb_size, GFP_KERNEL);
                        if (uvd->sbuf[i].data == NULL) {
                              errCode = -ENOMEM;
                              break;
                        }
                  }
            }
            if (errCode != 0) {
                  /* Have to free all that memory */
                  if (uvd->fbuf != NULL) {
                        usbvideo_rvfree(uvd->fbuf, uvd->fbuf_size);
                        uvd->fbuf = NULL;
                  }
                  RingQueue_Free(&uvd->dp);
                  for (i=0; i < USBVIDEO_NUMSBUF; i++) {
                        kfree(uvd->sbuf[i].data);
                        uvd->sbuf[i].data = NULL;
                  }
            }
      }

      /* If so far no errors then we shall start the camera */
      if (errCode == 0) {
            /* Start data pump if we have valid endpoint */
            if (uvd->video_endp != 0)
                  errCode = GET_CALLBACK(uvd, startDataPump)(uvd);
            if (errCode == 0) {
                  if (VALID_CALLBACK(uvd, setupOnOpen)) {
                        if (uvd->debug > 1)
                              info("%s: setupOnOpen callback", __FUNCTION__);
                        errCode = GET_CALLBACK(uvd, setupOnOpen)(uvd);
                        if (errCode < 0) {
                              err("%s: setupOnOpen callback failed (%d.).",
                                  __FUNCTION__, errCode);
                        } else if (uvd->debug > 1) {
                              info("%s: setupOnOpen callback successful", __FUNCTION__);
                        }
                  }
                  if (errCode == 0) {
                        uvd->settingsAdjusted = 0;
                        if (uvd->debug > 1)
                              info("%s: Open succeeded.", __FUNCTION__);
                        uvd->user++;
                        file->private_data = uvd;
                  }
            }
      }
      mutex_unlock(&uvd->lock);
      if (errCode != 0)
            usbvideo_ClientDecModCount(uvd);
      if (uvd->debug > 0)
            info("%s: Returning %d.", __FUNCTION__, errCode);
      return errCode;
}

/*
 * usbvideo_v4l_close()
 *
 * This is part of Video 4 Linux API. The procedure
 * stops streaming and deallocates all buffers that were earlier
 * allocated in usbvideo_v4l_open().
 *
 * History:
 * 22-Jan-2000 Moved scratch buffer deallocation here.
 * 27-Jan-2000 Used USBVIDEO_NUMSBUF as number of URB buffers.
 * 24-May-2000 Moved MOD_DEC_USE_COUNT outside of code that can sleep.
 */
static int usbvideo_v4l_close(struct inode *inode, struct file *file)
{
      struct video_device *dev = file->private_data;
      struct uvd *uvd = (struct uvd *) dev;
      int i;

      if (uvd->debug > 1)
            info("%s($%p)", __FUNCTION__, dev);

      mutex_lock(&uvd->lock);
      GET_CALLBACK(uvd, stopDataPump)(uvd);
      usbvideo_rvfree(uvd->fbuf, uvd->fbuf_size);
      uvd->fbuf = NULL;
      RingQueue_Free(&uvd->dp);

      for (i=0; i < USBVIDEO_NUMSBUF; i++) {
            kfree(uvd->sbuf[i].data);
            uvd->sbuf[i].data = NULL;
      }

#if USBVIDEO_REPORT_STATS
      usbvideo_ReportStatistics(uvd);
#endif

      uvd->user--;
      if (uvd->remove_pending) {
            if (uvd->debug > 0)
                  info("usbvideo_v4l_close: Final disconnect.");
            usbvideo_CameraRelease(uvd);
      }
      mutex_unlock(&uvd->lock);
      usbvideo_ClientDecModCount(uvd);

      if (uvd->debug > 1)
            info("%s: Completed.", __FUNCTION__);
      file->private_data = NULL;
      return 0;
}

/*
 * usbvideo_v4l_ioctl()
 *
 * This is part of Video 4 Linux API. The procedure handles ioctl() calls.
 *
 * History:
 * 22-Jan-2000 Corrected VIDIOCSPICT to reject unsupported settings.
 */
static int usbvideo_v4l_do_ioctl(struct inode *inode, struct file *file,
                         unsigned int cmd, void *arg)
{
      struct uvd *uvd = file->private_data;

      if (!CAMERA_IS_OPERATIONAL(uvd))
            return -EIO;

      switch (cmd) {
            case VIDIOCGCAP:
            {
                  struct video_capability *b = arg;
                  *b = uvd->vcap;
                  return 0;
            }
            case VIDIOCGCHAN:
            {
                  struct video_channel *v = arg;
                  *v = uvd->vchan;
                  return 0;
            }
            case VIDIOCSCHAN:
            {
                  struct video_channel *v = arg;
                  if (v->channel != 0)
                        return -EINVAL;
                  return 0;
            }
            case VIDIOCGPICT:
            {
                  struct video_picture *pic = arg;
                  *pic = uvd->vpic;
                  return 0;
            }
            case VIDIOCSPICT:
            {
                  struct video_picture *pic = arg;
                  /*
                   * Use temporary 'video_picture' structure to preserve our
                   * own settings (such as color depth, palette) that we
                   * aren't allowing everyone (V4L client) to change.
                   */
                  uvd->vpic.brightness = pic->brightness;
                  uvd->vpic.hue = pic->hue;
                  uvd->vpic.colour = pic->colour;
                  uvd->vpic.contrast = pic->contrast;
                  uvd->settingsAdjusted = 0;    /* Will force new settings */
                  return 0;
            }
            case VIDIOCSWIN:
            {
                  struct video_window *vw = arg;

                  if(VALID_CALLBACK(uvd, setVideoMode)) {
                        return GET_CALLBACK(uvd, setVideoMode)(uvd, vw);
                  }

                  if (vw->flags)
                        return -EINVAL;
                  if (vw->clipcount)
                        return -EINVAL;
                  if (vw->width != VIDEOSIZE_X(uvd->canvas))
                        return -EINVAL;
                  if (vw->height != VIDEOSIZE_Y(uvd->canvas))
                        return -EINVAL;

                  return 0;
            }
            case VIDIOCGWIN:
            {
                  struct video_window *vw = arg;

                  vw->x = 0;
                  vw->y = 0;
                  vw->width = VIDEOSIZE_X(uvd->videosize);
                  vw->height = VIDEOSIZE_Y(uvd->videosize);
                  vw->chromakey = 0;
                  if (VALID_CALLBACK(uvd, getFPS))
                        vw->flags = GET_CALLBACK(uvd, getFPS)(uvd);
                  else
                        vw->flags = 10; /* FIXME: do better! */
                  return 0;
            }
            case VIDIOCGMBUF:
            {
                  struct video_mbuf *vm = arg;
                  int i;

                  memset(vm, 0, sizeof(*vm));
                  vm->size = uvd->max_frame_size * USBVIDEO_NUMFRAMES;
                  vm->frames = USBVIDEO_NUMFRAMES;
                  for(i = 0; i < USBVIDEO_NUMFRAMES; i++)
                    vm->offsets[i] = i * uvd->max_frame_size;

                  return 0;
            }
            case VIDIOCMCAPTURE:
            {
                  struct video_mmap *vm = arg;

                  if (uvd->debug >= 1) {
                        info("VIDIOCMCAPTURE: frame=%d. size=%dx%d, format=%d.",
                             vm->frame, vm->width, vm->height, vm->format);
                  }
                  /*
                   * Check if the requested size is supported. If the requestor
                   * requests too big a frame then we may be tricked into accessing
                   * outside of own preallocated frame buffer (in uvd->frame).
                   * This will cause oops or a security hole. Theoretically, we
                   * could only clamp the size down to acceptable bounds, but then
                   * we'd need to figure out how to insert our smaller buffer into
                   * larger caller's buffer... this is not an easy question. So we
                   * here just flatly reject too large requests, assuming that the
                   * caller will resubmit with smaller size. Callers should know
                   * what size we support (returned by VIDIOCGCAP). However vidcat,
                   * for one, does not care and allows to ask for any size.
                   */
                  if ((vm->width > VIDEOSIZE_X(uvd->canvas)) ||
                      (vm->height > VIDEOSIZE_Y(uvd->canvas))) {
                        if (uvd->debug > 0) {
                              info("VIDIOCMCAPTURE: Size=%dx%d too large; "
                                   "allowed only up to %ldx%ld", vm->width, vm->height,
                                   VIDEOSIZE_X(uvd->canvas), VIDEOSIZE_Y(uvd->canvas));
                        }
                        return -EINVAL;
                  }
                  /* Check if the palette is supported */
                  if (((1L << vm->format) & uvd->paletteBits) == 0) {
                        if (uvd->debug > 0) {
                              info("VIDIOCMCAPTURE: format=%d. not supported"
                                   " (paletteBits=$%08lx)",
                                   vm->format, uvd->paletteBits);
                        }
                        return -EINVAL;
                  }
                  if ((vm->frame < 0) || (vm->frame >= USBVIDEO_NUMFRAMES)) {
                        err("VIDIOCMCAPTURE: vm.frame=%d. !E [0-%d]", vm->frame, USBVIDEO_NUMFRAMES-1);
                        return -EINVAL;
                  }
                  if (uvd->frame[vm->frame].frameState == FrameState_Grabbing) {
                        /* Not an error - can happen */
                  }
                  uvd->frame[vm->frame].request = VIDEOSIZE(vm->width, vm->height);
                  uvd->frame[vm->frame].palette = vm->format;

                  /* Mark it as ready */
                  uvd->frame[vm->frame].frameState = FrameState_Ready;

                  return usbvideo_NewFrame(uvd, vm->frame);
            }
            case VIDIOCSYNC:
            {
                  int *frameNum = arg;
                  int ret;

                  if (*frameNum < 0 || *frameNum >= USBVIDEO_NUMFRAMES)
                        return -EINVAL;

                  if (uvd->debug >= 1)
                        info("VIDIOCSYNC: syncing to frame %d.", *frameNum);
                  if (uvd->flags & FLAGS_NO_DECODING)
                        ret = usbvideo_GetFrame(uvd, *frameNum);
                  else if (VALID_CALLBACK(uvd, getFrame)) {
                        ret = GET_CALLBACK(uvd, getFrame)(uvd, *frameNum);
                        if ((ret < 0) && (uvd->debug >= 1)) {
                              err("VIDIOCSYNC: getFrame() returned %d.", ret);
                        }
                  } else {
                        err("VIDIOCSYNC: getFrame is not set");
                        ret = -EFAULT;
                  }

                  /*
                   * The frame is in FrameState_Done_Hold state. Release it
                   * right now because its data is already mapped into
                   * the user space and it's up to the application to
                   * make use of it until it asks for another frame.
                   */
                  uvd->frame[*frameNum].frameState = FrameState_Unused;
                  return ret;
            }
            case VIDIOCGFBUF:
            {
                  struct video_buffer *vb = arg;

                  memset(vb, 0, sizeof(*vb));
                  return 0;
            }
            case VIDIOCKEY:
                  return 0;

            case VIDIOCCAPTURE:
                  return -EINVAL;

            case VIDIOCSFBUF:

            case VIDIOCGTUNER:
            case VIDIOCSTUNER:

            case VIDIOCGFREQ:
            case VIDIOCSFREQ:

            case VIDIOCGAUDIO:
            case VIDIOCSAUDIO:
                  return -EINVAL;

            default:
                  return -ENOIOCTLCMD;
      }
      return 0;
}

static int usbvideo_v4l_ioctl(struct inode *inode, struct file *file,
                   unsigned int cmd, unsigned long arg)
{
      return video_usercopy(inode, file, cmd, arg, usbvideo_v4l_do_ioctl);
}

/*
 * usbvideo_v4l_read()
 *
 * This is mostly boring stuff. We simply ask for a frame and when it
 * arrives copy all the video data from it into user space. There is
 * no obvious need to override this method.
 *
 * History:
 * 20-Oct-2000 Created.
 * 01-Nov-2000 Added mutex (uvd->lock).
 */
static ssize_t usbvideo_v4l_read(struct file *file, char __user *buf,
                  size_t count, loff_t *ppos)
{
      struct uvd *uvd = file->private_data;
      int noblock = file->f_flags & O_NONBLOCK;
      int frmx = -1, i;
      struct usbvideo_frame *frame;

      if (!CAMERA_IS_OPERATIONAL(uvd) || (buf == NULL))
            return -EFAULT;

      if (uvd->debug >= 1)
            info("%s: %Zd. bytes, noblock=%d.", __FUNCTION__, count, noblock);

      mutex_lock(&uvd->lock);

      /* See if a frame is completed, then use it. */
      for(i = 0; i < USBVIDEO_NUMFRAMES; i++) {
            if ((uvd->frame[i].frameState == FrameState_Done) ||
                (uvd->frame[i].frameState == FrameState_Done_Hold) ||
                (uvd->frame[i].frameState == FrameState_Error)) {
                  frmx = i;
                  break;
            }
      }

      /* FIXME: If we don't start a frame here then who ever does? */
      if (noblock && (frmx == -1)) {
            count = -EAGAIN;
            goto read_done;
      }

      /*
       * If no FrameState_Done, look for a FrameState_Grabbing state.
       * See if a frame is in process (grabbing), then use it.
       * We will need to wait until it becomes cooked, of course.
       */
      if (frmx == -1) {
            for(i = 0; i < USBVIDEO_NUMFRAMES; i++) {
                  if (uvd->frame[i].frameState == FrameState_Grabbing) {
                        frmx = i;
                        break;
                  }
            }
      }

      /*
       * If no frame is active, start one. We don't care which one
       * it will be, so #0 is as good as any.
       * In read access mode we don't have convenience of VIDIOCMCAPTURE
       * to specify the requested palette (video format) on per-frame
       * basis. This means that we have to return data in -some- format
       * and just hope that the client knows what to do with it.
       * The default format is configured in uvd->defaultPalette field
       * as one of VIDEO_PALETTE_xxx values. We stuff it into the new
       * frame and initiate the frame filling process.
       */
      if (frmx == -1) {
            if (uvd->defaultPalette == 0) {
                  err("%s: No default palette; don't know what to do!", __FUNCTION__);
                  count = -EFAULT;
                  goto read_done;
            }
            frmx = 0;
            /*
             * We have no per-frame control over video size.
             * Therefore we only can use whatever size was
             * specified as default.
             */
            uvd->frame[frmx].request = uvd->videosize;
            uvd->frame[frmx].palette = uvd->defaultPalette;
            uvd->frame[frmx].frameState = FrameState_Ready;
            usbvideo_NewFrame(uvd, frmx);
            /* Now frame 0 is supposed to start filling... */
      }

      /*
       * Get a pointer to the active frame. It is either previously
       * completed frame or frame in progress but not completed yet.
       */
      frame = &uvd->frame[frmx];

      /*
       * Sit back & wait until the frame gets filled and postprocessed.
       * If we fail to get the picture [in time] then return the error.
       * In this call we specify that we want the frame to be waited for,
       * postprocessed and switched into FrameState_Done_Hold state. This
       * state is used to hold the frame as "fully completed" between
       * subsequent partial reads of the same frame.
       */
      if (frame->frameState != FrameState_Done_Hold) {
            long rv = -EFAULT;
            if (uvd->flags & FLAGS_NO_DECODING)
                  rv = usbvideo_GetFrame(uvd, frmx);
            else if (VALID_CALLBACK(uvd, getFrame))
                  rv = GET_CALLBACK(uvd, getFrame)(uvd, frmx);
            else
                  err("getFrame is not set");
            if ((rv != 0) || (frame->frameState != FrameState_Done_Hold)) {
                  count = rv;
                  goto read_done;
            }
      }

      /*
       * Copy bytes to user space. We allow for partial reads, which
       * means that the user application can request read less than
       * the full frame size. It is up to the application to issue
       * subsequent calls until entire frame is read.
       *
       * First things first, make sure we don't copy more than we
       * have - even if the application wants more. That would be
       * a big security embarassment!
       */
      if ((count + frame->seqRead_Index) > frame->seqRead_Length)
            count = frame->seqRead_Length - frame->seqRead_Index;

      /*
       * Copy requested amount of data to user space. We start
       * copying from the position where we last left it, which
       * will be zero for a new frame (not read before).
       */
      if (copy_to_user(buf, frame->data + frame->seqRead_Index, count)) {
            count = -EFAULT;
            goto read_done;
      }

      /* Update last read position */
      frame->seqRead_Index += count;
      if (uvd->debug >= 1) {
            err("%s: {copy} count used=%Zd, new seqRead_Index=%ld",
                  __FUNCTION__, count, frame->seqRead_Index);
      }

      /* Finally check if the frame is done with and "release" it */
      if (frame->seqRead_Index >= frame->seqRead_Length) {
            /* All data has been read */
            frame->seqRead_Index = 0;

            /* Mark it as available to be used again. */
            uvd->frame[frmx].frameState = FrameState_Unused;
            if (usbvideo_NewFrame(uvd, (frmx + 1) % USBVIDEO_NUMFRAMES)) {
                  err("%s: usbvideo_NewFrame failed.", __FUNCTION__);
            }
      }
read_done:
      mutex_unlock(&uvd->lock);
      return count;
}

/*
 * Make all of the blocks of data contiguous
 */
static int usbvideo_CompressIsochronous(struct uvd *uvd, struct urb *urb)
{
      char *cdata;
      int i, totlen = 0;

      for (i = 0; i < urb->number_of_packets; i++) {
            int n = urb->iso_frame_desc[i].actual_length;
            int st = urb->iso_frame_desc[i].status;

            cdata = urb->transfer_buffer + urb->iso_frame_desc[i].offset;

            /* Detect and ignore errored packets */
            if (st < 0) {
                  if (uvd->debug >= 1)
                        err("Data error: packet=%d. len=%d. status=%d.", i, n, st);
                  uvd->stats.iso_err_count++;
                  continue;
            }

            /* Detect and ignore empty packets */
            if (n <= 0) {
                  uvd->stats.iso_skip_count++;
                  continue;
            }
            totlen += n;      /* Little local accounting */
            RingQueue_Enqueue(&uvd->dp, cdata, n);
      }
      return totlen;
}

static void usbvideo_IsocIrq(struct urb *urb, struct pt_regs *regs)
{
      int i, ret, len;
      struct uvd *uvd = urb->context;

      /* We don't want to do anything if we are about to be removed! */
      if (!CAMERA_IS_OPERATIONAL(uvd))
            return;
#if 0
      if (urb->actual_length > 0) {
            info("urb=$%p status=%d. errcount=%d. length=%d.",
                 urb, urb->status, urb->error_count, urb->actual_length);
      } else {
            static int c = 0;
            if (c++ % 100 == 0)
                  info("No Isoc data");
      }
#endif

      if (!uvd->streaming) {
            if (uvd->debug >= 1)
                  info("Not streaming, but interrupt!");
            return;
      }

      uvd->stats.urb_count++;
      if (urb->actual_length <= 0)
            goto urb_done_with;

      /* Copy the data received into ring queue */
      len = usbvideo_CompressIsochronous(uvd, urb);
      uvd->stats.urb_length = len;
      if (len <= 0)
            goto urb_done_with;

      /* Here we got some data */
      uvd->stats.data_count += len;
      RingQueue_WakeUpInterruptible(&uvd->dp);

urb_done_with:
      for (i = 0; i < FRAMES_PER_DESC; i++) {
            urb->iso_frame_desc[i].status = 0;
            urb->iso_frame_desc[i].actual_length = 0;
      }
      urb->status = 0;
      urb->dev = uvd->dev;
      ret = usb_submit_urb (urb, GFP_KERNEL);
      if(ret)
            err("usb_submit_urb error (%d)", ret);
      return;
}

/*
 * usbvideo_StartDataPump()
 *
 * History:
 * 27-Jan-2000 Used ibmcam->iface, ibmcam->ifaceAltActive instead
 *             of hardcoded values. Simplified by using for loop,
 *             allowed any number of URBs.
 */
static int usbvideo_StartDataPump(struct uvd *uvd)
{
      struct usb_device *dev = uvd->dev;
      int i, errFlag;

      if (uvd->debug > 1)
            info("%s($%p)", __FUNCTION__, uvd);

      if (!CAMERA_IS_OPERATIONAL(uvd)) {
            err("%s: Camera is not operational", __FUNCTION__);
            return -EFAULT;
      }
      uvd->curframe = -1;

      /* Alternate interface 1 is is the biggest frame size */
      i = usb_set_interface(dev, uvd->iface, uvd->ifaceAltActive);
      if (i < 0) {
            err("%s: usb_set_interface error", __FUNCTION__);
            uvd->last_error = i;
            return -EBUSY;
      }
      if (VALID_CALLBACK(uvd, videoStart))
            GET_CALLBACK(uvd, videoStart)(uvd);
      else
            err("%s: videoStart not set", __FUNCTION__);

      /* We double buffer the Iso lists */
      for (i=0; i < USBVIDEO_NUMSBUF; i++) {
            int j, k;
            struct urb *urb = uvd->sbuf[i].urb;
            urb->dev = dev;
            urb->context = uvd;
            urb->pipe = usb_rcvisocpipe(dev, uvd->video_endp);
            urb->interval = 1;
            urb->transfer_flags = URB_ISO_ASAP;
            urb->transfer_buffer = uvd->sbuf[i].data;
            urb->complete = usbvideo_IsocIrq;
            urb->number_of_packets = FRAMES_PER_DESC;
            urb->transfer_buffer_length = uvd->iso_packet_len * FRAMES_PER_DESC;
            for (j=k=0; j < FRAMES_PER_DESC; j++, k += uvd->iso_packet_len) {
                  urb->iso_frame_desc[j].offset = k;
                  urb->iso_frame_desc[j].length = uvd->iso_packet_len;
            }
      }

      /* Submit all URBs */
      for (i=0; i < USBVIDEO_NUMSBUF; i++) {
            errFlag = usb_submit_urb(uvd->sbuf[i].urb, GFP_KERNEL);
            if (errFlag)
                  err("%s: usb_submit_isoc(%d) ret %d", __FUNCTION__, i, errFlag);
      }

      uvd->streaming = 1;
      if (uvd->debug > 1)
            info("%s: streaming=1 video_endp=$%02x", __FUNCTION__, uvd->video_endp);
      return 0;
}

/*
 * usbvideo_StopDataPump()
 *
 * This procedure stops streaming and deallocates URBs. Then it
 * activates zero-bandwidth alt. setting of the video interface.
 *
 * History:
 * 22-Jan-2000 Corrected order of actions to work after surprise removal.
 * 27-Jan-2000 Used uvd->iface, uvd->ifaceAltInactive instead of hardcoded values.
 */
static void usbvideo_StopDataPump(struct uvd *uvd)
{
      int i, j;

      if ((uvd == NULL) || (!uvd->streaming) || (uvd->dev == NULL))
            return;

      if (uvd->debug > 1)
            info("%s($%p)", __FUNCTION__, uvd);

      /* Unschedule all of the iso td's */
      for (i=0; i < USBVIDEO_NUMSBUF; i++) {
            usb_kill_urb(uvd->sbuf[i].urb);
      }
      if (uvd->debug > 1)
            info("%s: streaming=0", __FUNCTION__);
      uvd->streaming = 0;

      if (!uvd->remove_pending) {
            /* Invoke minidriver's magic to stop the camera */
            if (VALID_CALLBACK(uvd, videoStop))
                  GET_CALLBACK(uvd, videoStop)(uvd);
            else
                  err("%s: videoStop not set", __FUNCTION__);

            /* Set packet size to 0 */
            j = usb_set_interface(uvd->dev, uvd->iface, uvd->ifaceAltInactive);
            if (j < 0) {
                  err("%s: usb_set_interface() error %d.", __FUNCTION__, j);
                  uvd->last_error = j;
            }
      }
}

/*
 * usbvideo_NewFrame()
 *
 * History:
 * 29-Mar-00 Added copying of previous frame into the current one.
 * 6-Aug-00  Added model 3 video sizes, removed redundant width, height.
 */
static int usbvideo_NewFrame(struct uvd *uvd, int framenum)
{
      struct usbvideo_frame *frame;
      int n;

      if (uvd->debug > 1)
            info("usbvideo_NewFrame($%p,%d.)", uvd, framenum);

      /* If we're not grabbing a frame right now and the other frame is */
      /*  ready to be grabbed into, then use it instead */
      if (uvd->curframe != -1)
            return 0;

      /* If necessary we adjust picture settings between frames */
      if (!uvd->settingsAdjusted) {
            if (VALID_CALLBACK(uvd, adjustPicture))
                  GET_CALLBACK(uvd, adjustPicture)(uvd);
            uvd->settingsAdjusted = 1;
      }

      n = (framenum + 1) % USBVIDEO_NUMFRAMES;
      if (uvd->frame[n].frameState == FrameState_Ready)
            framenum = n;

      frame = &uvd->frame[framenum];

      frame->frameState = FrameState_Grabbing;
      frame->scanstate = ScanState_Scanning;
      frame->seqRead_Length = 0;    /* Accumulated in xxx_parse_data() */
      frame->deinterlace = Deinterlace_None;
      frame->flags = 0; /* No flags yet, up to minidriver (or us) to set them */
      uvd->curframe = framenum;

      /*
       * Normally we would want to copy previous frame into the current one
       * before we even start filling it with data; this allows us to stop
       * filling at any moment; top portion of the frame will be new and
       * bottom portion will stay as it was in previous frame. If we don't
       * do that then missing chunks of video stream will result in flickering
       * portions of old data whatever it was before.
       *
       * If we choose not to copy previous frame (to, for example, save few
       * bus cycles - the frame can be pretty large!) then we have an option
       * to clear the frame before using. If we experience losses in this
       * mode then missing picture will be black (no flickering).
       *
       * Finally, if user chooses not to clean the current frame before
       * filling it with data then the old data will be visible if we fail
       * to refill entire frame with new data.
       */
      if (!(uvd->flags & FLAGS_SEPARATE_FRAMES)) {
            /* This copies previous frame into this one to mask losses */
            int prev = (framenum - 1 + USBVIDEO_NUMFRAMES) % USBVIDEO_NUMFRAMES;
            memmove(frame->data, uvd->frame[prev].data, uvd->max_frame_size);
      } else {
            if (uvd->flags & FLAGS_CLEAN_FRAMES) {
                  /* This provides a "clean" frame but slows things down */
                  memset(frame->data, 0, uvd->max_frame_size);
            }
      }
      return 0;
}

/*
 * usbvideo_CollectRawData()
 *
 * This procedure can be used instead of 'processData' callback if you
 * only want to dump the raw data from the camera into the output
 * device (frame buffer). You can look at it with V4L client, but the
 * image will be unwatchable. The main purpose of this code and of the
 * mode FLAGS_NO_DECODING is debugging and capturing of datastreams from
 * new, unknown cameras. This procedure will be automatically invoked
 * instead of the specified callback handler when uvd->flags has bit
 * FLAGS_NO_DECODING set. Therefore, any regular build of any driver
 * based on usbvideo can use this feature at any time.
 */
static void usbvideo_CollectRawData(struct uvd *uvd, struct usbvideo_frame *frame)
{
      int n;

      assert(uvd != NULL);
      assert(frame != NULL);

      /* Try to move data from queue into frame buffer */
      n = RingQueue_GetLength(&uvd->dp);
      if (n > 0) {
            int m;
            /* See how much space we have left */
            m = uvd->max_frame_size - frame->seqRead_Length;
            if (n > m)
                  n = m;
            /* Now move that much data into frame buffer */
            RingQueue_Dequeue(
                  &uvd->dp,
                  frame->data + frame->seqRead_Length,
                  m);
            frame->seqRead_Length += m;
      }
      /* See if we filled the frame */
      if (frame->seqRead_Length >= uvd->max_frame_size) {
            frame->frameState = FrameState_Done;
            uvd->curframe = -1;
            uvd->stats.frame_num++;
      }
}

static int usbvideo_GetFrame(struct uvd *uvd, int frameNum)
{
      struct usbvideo_frame *frame = &uvd->frame[frameNum];

      if (uvd->debug >= 2)
            info("%s($%p,%d.)", __FUNCTION__, uvd, frameNum);

      switch (frame->frameState) {
      case FrameState_Unused:
            if (uvd->debug >= 2)
                  info("%s: FrameState_Unused", __FUNCTION__);
            return -EINVAL;
      case FrameState_Ready:
      case FrameState_Grabbing:
      case FrameState_Error:
      {
            int ntries, signalPending;
      redo:
            if (!CAMERA_IS_OPERATIONAL(uvd)) {
                  if (uvd->debug >= 2)
                        info("%s: Camera is not operational (1)", __FUNCTION__);
                  return -EIO;
            }
            ntries = 0;
            do {
                  RingQueue_InterruptibleSleepOn(&uvd->dp);
                  signalPending = signal_pending(current);
                  if (!CAMERA_IS_OPERATIONAL(uvd)) {
                        if (uvd->debug >= 2)
                              info("%s: Camera is not operational (2)", __FUNCTION__);
                        return -EIO;
                  }
                  assert(uvd->fbuf != NULL);
                  if (signalPending) {
                        if (uvd->debug >= 2)
                              info("%s: Signal=$%08x", __FUNCTION__, signalPending);
                        if (uvd->flags & FLAGS_RETRY_VIDIOCSYNC) {
                              usbvideo_TestPattern(uvd, 1, 0);
                              uvd->curframe = -1;
                              uvd->stats.frame_num++;
                              if (uvd->debug >= 2)
                                    info("%s: Forced test pattern screen", __FUNCTION__);
                              return 0;
                        } else {
                              /* Standard answer: Interrupted! */
                              if (uvd->debug >= 2)
                                    info("%s: Interrupted!", __FUNCTION__);
                              return -EINTR;
                        }
                  } else {
                        /* No signals - we just got new data in dp queue */
                        if (uvd->flags & FLAGS_NO_DECODING)
                              usbvideo_CollectRawData(uvd, frame);
                        else if (VALID_CALLBACK(uvd, processData))
                              GET_CALLBACK(uvd, processData)(uvd, frame);
                        else
                              err("%s: processData not set", __FUNCTION__);
                  }
            } while (frame->frameState == FrameState_Grabbing);
            if (uvd->debug >= 2) {
                  info("%s: Grabbing done; state=%d. (%lu. bytes)",
                       __FUNCTION__, frame->frameState, frame->seqRead_Length);
            }
            if (frame->frameState == FrameState_Error) {
                  int ret = usbvideo_NewFrame(uvd, frameNum);
                  if (ret < 0) {
                        err("%s: usbvideo_NewFrame() failed (%d.)", __FUNCTION__, ret);
                        return ret;
                  }
                  goto redo;
            }
            /* Note that we fall through to meet our destiny below */
      }
      case FrameState_Done:
            /*
             * Do all necessary postprocessing of data prepared in
             * "interrupt" code and the collecting code above. The
             * frame gets marked as FrameState_Done by queue parsing code.
             * This status means that we collected enough data and
             * most likely processed it as we went through. However
             * the data may need postprocessing, such as deinterlacing
             * or picture adjustments implemented in software (horror!)
             *
             * As soon as the frame becomes "final" it gets promoted to
             * FrameState_Done_Hold status where it will remain until the
             * caller consumed all the video data from the frame. Then
             * the empty shell of ex-frame is thrown out for dogs to eat.
             * But we, worried about pets, will recycle the frame!
             */
            uvd->stats.frame_num++;
            if ((uvd->flags & FLAGS_NO_DECODING) == 0) {
                  if (VALID_CALLBACK(uvd, postProcess))
                        GET_CALLBACK(uvd, postProcess)(uvd, frame);
                  if (frame->flags & USBVIDEO_FRAME_FLAG_SOFTWARE_CONTRAST)
                        usbvideo_SoftwareContrastAdjustment(uvd, frame);
            }
            frame->frameState = FrameState_Done_Hold;
            if (uvd->debug >= 2)
                  info("%s: Entered FrameState_Done_Hold state.", __FUNCTION__);
            return 0;

      case FrameState_Done_Hold:
            /*
             * We stay in this state indefinitely until someone external,
             * like ioctl() or read() call finishes digesting the frame
             * data. Then it will mark the frame as FrameState_Unused and
             * it will be released back into the wild to roam freely.
             */
            if (uvd->debug >= 2)
                  info("%s: FrameState_Done_Hold state.", __FUNCTION__);
            return 0;
      }

      /* Catch-all for other cases. We shall not be here. */
      err("%s: Invalid state %d.", __FUNCTION__, frame->frameState);
      frame->frameState = FrameState_Unused;
      return 0;
}

/*
 * usbvideo_DeinterlaceFrame()
 *
 * This procedure deinterlaces the given frame. Some cameras produce
 * only half of scanlines - sometimes only even lines, sometimes only
 * odd lines. The deinterlacing method is stored in frame->deinterlace
 * variable.
 *
 * Here we scan the frame vertically and replace missing scanlines with
 * average between surrounding ones - before and after. If we have no
 * line above then we just copy next line. Similarly, if we need to
 * create a last line then preceding line is used.
 */
void usbvideo_DeinterlaceFrame(struct uvd *uvd, struct usbvideo_frame *frame)
{
      if ((uvd == NULL) || (frame == NULL))
            return;

      if ((frame->deinterlace == Deinterlace_FillEvenLines) ||
          (frame->deinterlace == Deinterlace_FillOddLines))
      {
            const int v4l_linesize = VIDEOSIZE_X(frame->request) * V4L_BYTES_PER_PIXEL;
            int i = (frame->deinterlace == Deinterlace_FillEvenLines) ? 0 : 1;

            for (; i < VIDEOSIZE_Y(frame->request); i += 2) {
                  const unsigned char *fs1, *fs2;
                  unsigned char *fd;
                  int ip, in, j;    /* Previous and next lines */

                  /*
                   * Need to average lines before and after 'i'.
                   * If we go out of bounds seeking those lines then
                   * we point back to existing line.
                   */
                  ip = i - 1; /* First, get rough numbers */
                  in = i + 1;

                  /* Now validate */
                  if (ip < 0)
                        ip = in;
                  if (in >= VIDEOSIZE_Y(frame->request))
                        in = ip;

                  /* Sanity check */
                  if ((ip < 0) || (in < 0) ||
                      (ip >= VIDEOSIZE_Y(frame->request)) ||
                      (in >= VIDEOSIZE_Y(frame->request)))
                  {
                        err("Error: ip=%d. in=%d. req.height=%ld.",
                            ip, in, VIDEOSIZE_Y(frame->request));
                        break;
                  }

                  /* Now we need to average lines 'ip' and 'in' to produce line 'i' */
                  fs1 = frame->data + (v4l_linesize * ip);
                  fs2 = frame->data + (v4l_linesize * in);
                  fd = frame->data + (v4l_linesize * i);

                  /* Average lines around destination */
                  for (j=0; j < v4l_linesize; j++) {
                        fd[j] = (unsigned char)((((unsigned) fs1[j]) +
                                           ((unsigned)fs2[j])) >> 1);
                  }
            }
      }

      /* Optionally display statistics on the screen */
      if (uvd->flags & FLAGS_OVERLAY_STATS)
            usbvideo_OverlayStats(uvd, frame);
}

EXPORT_SYMBOL(usbvideo_DeinterlaceFrame);

/*
 * usbvideo_SoftwareContrastAdjustment()
 *
 * This code adjusts the contrast of the frame, assuming RGB24 format.
 * As most software image processing, this job is CPU-intensive.
 * Get a camera that supports hardware adjustment!
 *
 * History:
 * 09-Feb-2001  Created.
 */
static void usbvideo_SoftwareContrastAdjustment(struct uvd *uvd,
                                    struct usbvideo_frame *frame)
{
      int i, j, v4l_linesize;
      signed long adj;
      const int ccm = 128; /* Color correction median - see below */

      if ((uvd == NULL) || (frame == NULL)) {
            err("%s: Illegal call.", __FUNCTION__);
            return;
      }
      adj = (uvd->vpic.contrast - 0x8000) >> 8; /* -128..+127 = -ccm..+(ccm-1)*/
      RESTRICT_TO_RANGE(adj, -ccm, ccm+1);
      if (adj == 0) {
            /* In rare case of no adjustment */
            return;
      }
      v4l_linesize = VIDEOSIZE_X(frame->request) * V4L_BYTES_PER_PIXEL;
      for (i=0; i < VIDEOSIZE_Y(frame->request); i++) {
            unsigned char *fd = frame->data + (v4l_linesize * i);
            for (j=0; j < v4l_linesize; j++) {
                  signed long v = (signed long) fd[j];
                  /* Magnify up to 2 times, reduce down to zero */
                  v = 128 + ((ccm + adj) * (v - 128)) / ccm;
                  RESTRICT_TO_RANGE(v, 0, 0xFF); /* Must flatten tails */
                  fd[j] = (unsigned char) v;
            }
      }
}

MODULE_LICENSE("GPL");

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