text: /****************************************************************************
   *
   *  Filename: cpia2_usb.c
   *
   *  Copyright 2001, STMicrolectronics, Inc.
   *      Contact:  steve.miller@st.com
   *
   *  Description:
   *     This is a USB driver for CPia2 based video cameras.
   *     The infrastructure of this driver is based on the cpia usb driver by
   *     Jochen Scharrlach and Johannes Erdfeldt.
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   *
   *  Stripped of 2.4 stuff ready for main kernel submit by
   *		Alan Cox <alan@lxorguk.ukuu.org.uk>
   ****************************************************************************/
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/usb.h>
  #include <linux/module.h>
  
  #include "cpia2.h"
  
  static int frame_sizes[] = {
  	0,	// USBIF_CMDONLY
  	0, 	// USBIF_BULK
  	128, 	// USBIF_ISO_1
  	384, 	// USBIF_ISO_2
  	640, 	// USBIF_ISO_3
  	768, 	// USBIF_ISO_4
  	896, 	// USBIF_ISO_5
  	1023, 	// USBIF_ISO_6
  };
  
  #define FRAMES_PER_DESC    10
  #define FRAME_SIZE_PER_DESC   frame_sizes[cam->cur_alt]
  
  static void process_frame(struct camera_data *cam);
  static void cpia2_usb_complete(struct urb *urb);
  static int cpia2_usb_probe(struct usb_interface *intf,
  			   const struct usb_device_id *id);
  static void cpia2_usb_disconnect(struct usb_interface *intf);
  static int cpia2_usb_suspend(struct usb_interface *intf, pm_message_t message);
  static int cpia2_usb_resume(struct usb_interface *intf);
  
  static void free_sbufs(struct camera_data *cam);
  static void add_APPn(struct camera_data *cam);
  static void add_COM(struct camera_data *cam);
  static int submit_urbs(struct camera_data *cam);
  static int set_alternate(struct camera_data *cam, unsigned int alt);
  static int configure_transfer_mode(struct camera_data *cam, unsigned int alt);
  
  static struct usb_device_id cpia2_id_table[] = {
  	{USB_DEVICE(0x0553, 0x0100)},
  	{USB_DEVICE(0x0553, 0x0140)},
  	{USB_DEVICE(0x0553, 0x0151)},  /* STV0676 */
  	{}			/* Terminating entry */
  };
  MODULE_DEVICE_TABLE(usb, cpia2_id_table);
  
  static struct usb_driver cpia2_driver = {
  	.name		= "cpia2",
  	.probe		= cpia2_usb_probe,
  	.disconnect	= cpia2_usb_disconnect,
  	.suspend	= cpia2_usb_suspend,
  	.resume		= cpia2_usb_resume,
  	.reset_resume	= cpia2_usb_resume,
  	.id_table	= cpia2_id_table
  };
  
  
  /******************************************************************************
   *
   *  process_frame
   *
   *****************************************************************************/
  static void process_frame(struct camera_data *cam)
  {
  	static int frame_count;
  
  	unsigned char *inbuff = cam->workbuff->data;
  
  	DBG("Processing frame #%d, current:%d\n",
  	    cam->workbuff->num, cam->curbuff->num);
  
  	if(cam->workbuff->length > cam->workbuff->max_length)
  		cam->workbuff->max_length = cam->workbuff->length;
  
  	if ((inbuff[0] == 0xFF) && (inbuff[1] == 0xD8)) {
  		frame_count++;
  	} else {
  		cam->workbuff->status = FRAME_ERROR;
  		DBG("Start of frame not found\n");
  		return;
  	}
  
  	/***
  	 * Now the output buffer should have a JPEG image in it.
  	 ***/
  	if(!cam->first_image_seen) {
  		/* Always skip the first image after streaming
  		 * starts. It is almost certainly corrupt. */
  		cam->first_image_seen = 1;
  		cam->workbuff->status = FRAME_EMPTY;
  		return;
  	}
  	if (cam->workbuff->length > 3) {
  		if(cam->mmapped &&
  		   cam->workbuff->length < cam->workbuff->max_length) {
  			/* No junk in the buffers */
  			memset(cam->workbuff->data+cam->workbuff->length,
  			       0, cam->workbuff->max_length-
  				  cam->workbuff->length);
  		}
  		cam->workbuff->max_length = cam->workbuff->length;
  		cam->workbuff->status = FRAME_READY;
  
  		if(!cam->mmapped && cam->num_frames > 2) {
  			/* During normal reading, the most recent
  			 * frame will be read.  If the current frame
  			 * hasn't started reading yet, it will never
  			 * be read, so mark it empty.  If the buffer is
  			 * mmapped, or we have few buffers, we need to
  			 * wait for the user to free the buffer.
  			 *
  			 * NOTE: This is not entirely foolproof with 3
  			 * buffers, but it would take an EXTREMELY
  			 * overloaded system to cause problems (possible
  			 * image data corruption).  Basically, it would
  			 * need to take more time to execute cpia2_read
  			 * than it would for the camera to send
  			 * cam->num_frames-2 frames before problems
  			 * could occur.
  			 */
  			cam->curbuff->status = FRAME_EMPTY;
  		}
  		cam->curbuff = cam->workbuff;
  		cam->workbuff = cam->workbuff->next;
  		DBG("Changed buffers, work:%d, current:%d\n",
  		    cam->workbuff->num, cam->curbuff->num);
  		return;
  	} else {
  		DBG("Not enough data for an image.\n");
  	}
  
  	cam->workbuff->status = FRAME_ERROR;
  	return;
  }
  
  /******************************************************************************
   *
   *  add_APPn
   *
   *  Adds a user specified APPn record
   *****************************************************************************/
  static void add_APPn(struct camera_data *cam)
  {
  	if(cam->APP_len > 0) {
  		cam->workbuff->data[cam->workbuff->length++] = 0xFF;
  		cam->workbuff->data[cam->workbuff->length++] = 0xE0+cam->APPn;
  		cam->workbuff->data[cam->workbuff->length++] = 0;
  		cam->workbuff->data[cam->workbuff->length++] = cam->APP_len+2;
  		memcpy(cam->workbuff->data+cam->workbuff->length,
  		       cam->APP_data, cam->APP_len);
  		cam->workbuff->length += cam->APP_len;
  	}
  }
  
  /******************************************************************************
   *
   *  add_COM
   *
   *  Adds a user specified COM record
   *****************************************************************************/
  static void add_COM(struct camera_data *cam)
  {
  	if(cam->COM_len > 0) {
  		cam->workbuff->data[cam->workbuff->length++] = 0xFF;
  		cam->workbuff->data[cam->workbuff->length++] = 0xFE;
  		cam->workbuff->data[cam->workbuff->length++] = 0;
  		cam->workbuff->data[cam->workbuff->length++] = cam->COM_len+2;
  		memcpy(cam->workbuff->data+cam->workbuff->length,
  		       cam->COM_data, cam->COM_len);
  		cam->workbuff->length += cam->COM_len;
  	}
  }
  
  /******************************************************************************
   *
   *  cpia2_usb_complete
   *
   *  callback when incoming packet is received
   *****************************************************************************/
  static void cpia2_usb_complete(struct urb *urb)
  {
  	int i;
  	unsigned char *cdata;
  	static bool frame_ready = false;
  	struct camera_data *cam = (struct camera_data *) urb->context;
  
  	if (urb->status!=0) {
  		if (!(urb->status == -ENOENT ||
  		      urb->status == -ECONNRESET ||
  		      urb->status == -ESHUTDOWN))
  		{
  			DBG("urb->status = %d!\n", urb->status);
  		}
  		DBG("Stopping streaming\n");
  		return;
  	}
  
  	if (!cam->streaming || !video_is_registered(&cam->vdev)) {
  		LOG("Will now stop the streaming: streaming = %d, present=%d\n",
  		    cam->streaming, video_is_registered(&cam->vdev));
  		return;
  	}
  
  	/***
  	 * Packet collater
  	 ***/
  	//DBG("Collating %d packets\n", urb->number_of_packets);
  	for (i = 0; i < urb->number_of_packets; i++) {
  		u16 checksum, iso_checksum;
  		int j;
  		int n = urb->iso_frame_desc[i].actual_length;
  		int st = urb->iso_frame_desc[i].status;
  
  		if(cam->workbuff->status == FRAME_READY) {
  			struct framebuf *ptr;
  			/* Try to find an available buffer */
  			DBG("workbuff full, searching\n");
  			for (ptr = cam->workbuff->next;
  			     ptr != cam->workbuff;
  			     ptr = ptr->next)
  			{
  				if (ptr->status == FRAME_EMPTY) {
  					ptr->status = FRAME_READING;
  					ptr->length = 0;
  					break;
  				}
  			}
  			if (ptr == cam->workbuff)
  				break; /* No READING or EMPTY buffers left */
  
  			cam->workbuff = ptr;
  		}
  
  		if (cam->workbuff->status == FRAME_EMPTY ||
  		    cam->workbuff->status == FRAME_ERROR) {
  			cam->workbuff->status = FRAME_READING;
  			cam->workbuff->length = 0;
  		}
  
  		//DBG("   Packet %d length = %d, status = %d\n", i, n, st);
  		cdata = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
  
  		if (st) {
  			LOG("cpia2 data error: [%d] len=%d, status = %d\n",
  			    i, n, st);
  			if(!ALLOW_CORRUPT)
  				cam->workbuff->status = FRAME_ERROR;
  			continue;
  		}
  
  		if(n<=2)
  			continue;
  
  		checksum = 0;
  		for(j=0; j<n-2; ++j)
  			checksum += cdata[j];
  		iso_checksum = cdata[j] + cdata[j+1]*256;
  		if(checksum != iso_checksum) {
  			LOG("checksum mismatch: [%d] len=%d, calculated = %x, checksum = %x\n",
  			    i, n, (int)checksum, (int)iso_checksum);
  			if(!ALLOW_CORRUPT) {
  				cam->workbuff->status = FRAME_ERROR;
  				continue;
  			}
  		}
  		n -= 2;
  
  		if(cam->workbuff->status != FRAME_READING) {
  			if((0xFF == cdata[0] && 0xD8 == cdata[1]) ||
  			   (0xD8 == cdata[0] && 0xFF == cdata[1] &&
  			    0 != cdata[2])) {
  				/* frame is skipped, but increment total
  				 * frame count anyway */
  				cam->frame_count++;
  			}
  			DBG("workbuff not reading, status=%d\n",
  			    cam->workbuff->status);
  			continue;
  		}
  
  		if (cam->frame_size < cam->workbuff->length + n) {
  			ERR("buffer overflow! length: %d, n: %d\n",
  			    cam->workbuff->length, n);
  			cam->workbuff->status = FRAME_ERROR;
  			if(cam->workbuff->length > cam->workbuff->max_length)
  				cam->workbuff->max_length =
  					cam->workbuff->length;
  			continue;
  		}
  
  		if (cam->workbuff->length == 0) {
  			int data_offset;
  			if ((0xD8 == cdata[0]) && (0xFF == cdata[1])) {
  				data_offset = 1;
  			} else if((0xFF == cdata[0]) && (0xD8 == cdata[1])
  				  && (0xFF == cdata[2])) {
  				data_offset = 2;
  			} else {
  				DBG("Ignoring packet, not beginning!\n");
  				continue;
  			}
  			DBG("Start of frame pattern found\n");
  			v4l2_get_timestamp(&cam->workbuff->timestamp);
  			cam->workbuff->seq = cam->frame_count++;
  			cam->workbuff->data[0] = 0xFF;
  			cam->workbuff->data[1] = 0xD8;
  			cam->workbuff->length = 2;
  			add_APPn(cam);
  			add_COM(cam);
  			memcpy(cam->workbuff->data+cam->workbuff->length,
  			       cdata+data_offset, n-data_offset);
  			cam->workbuff->length += n-data_offset;
  		} else if (cam->workbuff->length > 0) {
  			memcpy(cam->workbuff->data + cam->workbuff->length,
  			       cdata, n);
  			cam->workbuff->length += n;
  		}
  
  		if ((cam->workbuff->length >= 3) &&
  		    (cam->workbuff->data[cam->workbuff->length - 3] == 0xFF) &&
  		    (cam->workbuff->data[cam->workbuff->length - 2] == 0xD9) &&
  		    (cam->workbuff->data[cam->workbuff->length - 1] == 0xFF)) {
  			frame_ready = true;
  			cam->workbuff->data[cam->workbuff->length - 1] = 0;
  			cam->workbuff->length -= 1;
  		} else if ((cam->workbuff->length >= 2) &&
  		   (cam->workbuff->data[cam->workbuff->length - 2] == 0xFF) &&
  		   (cam->workbuff->data[cam->workbuff->length - 1] == 0xD9)) {
  			frame_ready = true;
  		}
  
  		if (frame_ready) {
  			DBG("Workbuff image size = %d\n",cam->workbuff->length);
  			process_frame(cam);
  
  			frame_ready = false;
  
  			if (waitqueue_active(&cam->wq_stream))
  				wake_up_interruptible(&cam->wq_stream);
  		}
  	}
  
  	if(cam->streaming) {
  		/* resubmit */
  		urb->dev = cam->dev;
  		if ((i = usb_submit_urb(urb, GFP_ATOMIC)) != 0)
  			ERR("%s: usb_submit_urb ret %d!\n", __func__, i);
  	}
  }
  
  /******************************************************************************
   *
   * configure_transfer_mode
   *
   *****************************************************************************/
  static int configure_transfer_mode(struct camera_data *cam, unsigned int alt)
  {
  	static unsigned char iso_regs[8][4] = {
  		{0x00, 0x00, 0x00, 0x00},
  		{0x00, 0x00, 0x00, 0x00},
  		{0xB9, 0x00, 0x00, 0x7E},
  		{0xB9, 0x00, 0x01, 0x7E},
  		{0xB9, 0x00, 0x02, 0x7E},
  		{0xB9, 0x00, 0x02, 0xFE},
  		{0xB9, 0x00, 0x03, 0x7E},
  		{0xB9, 0x00, 0x03, 0xFD}
  	};
  	struct cpia2_command cmd;
  	unsigned char reg;
  
  	if (!video_is_registered(&cam->vdev))
  		return -ENODEV;
  
  	/***
  	 * Write the isoc registers according to the alternate selected
  	 ***/
  	cmd.direction = TRANSFER_WRITE;
  	cmd.buffer.block_data[0] = iso_regs[alt][0];
  	cmd.buffer.block_data[1] = iso_regs[alt][1];
  	cmd.buffer.block_data[2] = iso_regs[alt][2];
  	cmd.buffer.block_data[3] = iso_regs[alt][3];
  	cmd.req_mode = CAMERAACCESS_TYPE_BLOCK | CAMERAACCESS_VC;
  	cmd.start = CPIA2_VC_USB_ISOLIM;
  	cmd.reg_count = 4;
  	cpia2_send_command(cam, &cmd);
  
  	/***
  	 * Enable relevant streams before starting polling.
  	 * First read USB Stream Config Register.
  	 ***/
  	cmd.direction = TRANSFER_READ;
  	cmd.req_mode = CAMERAACCESS_TYPE_BLOCK | CAMERAACCESS_VC;
  	cmd.start = CPIA2_VC_USB_STRM;
  	cmd.reg_count = 1;
  	cpia2_send_command(cam, &cmd);
  	reg = cmd.buffer.block_data[0];
  
  	/* Clear iso, bulk, and int */
  	reg &= ~(CPIA2_VC_USB_STRM_BLK_ENABLE |
  		 CPIA2_VC_USB_STRM_ISO_ENABLE |
  		 CPIA2_VC_USB_STRM_INT_ENABLE);
  
  	if (alt == USBIF_BULK) {
  		DBG("Enabling bulk xfer\n");
  		reg |= CPIA2_VC_USB_STRM_BLK_ENABLE;	/* Enable Bulk */
  		cam->xfer_mode = XFER_BULK;
  	} else if (alt >= USBIF_ISO_1) {
  		DBG("Enabling ISOC xfer\n");
  		reg |= CPIA2_VC_USB_STRM_ISO_ENABLE;
  		cam->xfer_mode = XFER_ISOC;
  	}
  
  	cmd.buffer.block_data[0] = reg;
  	cmd.direction = TRANSFER_WRITE;
  	cmd.start = CPIA2_VC_USB_STRM;
  	cmd.reg_count = 1;
  	cmd.req_mode = CAMERAACCESS_TYPE_BLOCK | CAMERAACCESS_VC;
  	cpia2_send_command(cam, &cmd);
  
  	return 0;
  }
  
  /******************************************************************************
   *
   * cpia2_usb_change_streaming_alternate
   *
   *****************************************************************************/
  int cpia2_usb_change_streaming_alternate(struct camera_data *cam,
  					 unsigned int alt)
  {
  	int ret = 0;
  
  	if(alt < USBIF_ISO_1 || alt > USBIF_ISO_6)
  		return -EINVAL;
  
  	if(alt == cam->params.camera_state.stream_mode)
  		return 0;
  
  	cpia2_usb_stream_pause(cam);
  
  	configure_transfer_mode(cam, alt);
  
  	cam->params.camera_state.stream_mode = alt;
  
  	/* Reset the camera to prevent image quality degradation */
  	cpia2_reset_camera(cam);
  
  	cpia2_usb_stream_resume(cam);
  
  	return ret;
  }
  
  /******************************************************************************
   *
   * set_alternate
   *
   *****************************************************************************/
  static int set_alternate(struct camera_data *cam, unsigned int alt)
  {
  	int ret = 0;
  
  	if(alt == cam->cur_alt)
  		return 0;
  
  	if (cam->cur_alt != USBIF_CMDONLY) {
  		DBG("Changing from alt %d to %d\n", cam->cur_alt, USBIF_CMDONLY);
  		ret = usb_set_interface(cam->dev, cam->iface, USBIF_CMDONLY);
  		if (ret != 0)
  			return ret;
  	}
  	if (alt != USBIF_CMDONLY) {
  		DBG("Changing from alt %d to %d\n", USBIF_CMDONLY, alt);
  		ret = usb_set_interface(cam->dev, cam->iface, alt);
  		if (ret != 0)
  			return ret;
  	}
  
  	cam->old_alt = cam->cur_alt;
  	cam->cur_alt = alt;
  
  	return ret;
  }
  
  /******************************************************************************
   *
   * free_sbufs
   *
   * Free all cam->sbuf[]. All non-NULL .data and .urb members that are non-NULL
   * are assumed to be allocated. Non-NULL .urb members are also assumed to be
   * submitted (and must therefore be killed before they are freed).
   *****************************************************************************/
  static void free_sbufs(struct camera_data *cam)
  {
  	int i;
  
  	for (i = 0; i < NUM_SBUF; i++) {
  		if(cam->sbuf[i].urb) {
  			usb_kill_urb(cam->sbuf[i].urb);
  			usb_free_urb(cam->sbuf[i].urb);
  			cam->sbuf[i].urb = NULL;
  		}
  		if(cam->sbuf[i].data) {
  			kfree(cam->sbuf[i].data);
  			cam->sbuf[i].data = NULL;
  		}
  	}
  }
  
  /*******
  * Convenience functions
  *******/
  /****************************************************************************
   *
   *  write_packet
   *
   ***************************************************************************/
  static int write_packet(struct usb_device *udev,
  			u8 request, u8 * registers, u16 start, size_t size)
  {
  	if (!registers || size <= 0)
  		return -EINVAL;
  
  	return usb_control_msg(udev,
  			       usb_sndctrlpipe(udev, 0),
  			       request,
  			       USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  			       start,	/* value */
  			       0,	/* index */
  			       registers,	/* buffer */
  			       size,
  			       HZ);
  }
  
  /****************************************************************************
   *
   *  read_packet
   *
   ***************************************************************************/
  static int read_packet(struct usb_device *udev,
  		       u8 request, u8 * registers, u16 start, size_t size)
  {
  	if (!registers || size <= 0)
  		return -EINVAL;
  
  	return usb_control_msg(udev,
  			       usb_rcvctrlpipe(udev, 0),
  			       request,
  			       USB_DIR_IN|USB_TYPE_VENDOR|USB_RECIP_DEVICE,
  			       start,	/* value */
  			       0,	/* index */
  			       registers,	/* buffer */
  			       size,
  			       HZ);
  }
  
  /******************************************************************************
   *
   *  cpia2_usb_transfer_cmd
   *
   *****************************************************************************/
  int cpia2_usb_transfer_cmd(struct camera_data *cam,
  			   void *registers,
  			   u8 request, u8 start, u8 count, u8 direction)
  {
  	int err = 0;
  	struct usb_device *udev = cam->dev;
  
  	if (!udev) {
  		ERR("%s: Internal driver error: udev is NULL\n", __func__);
  		return -EINVAL;
  	}
  
  	if (!registers) {
  		ERR("%s: Internal driver error: register array is NULL\n", __func__);
  		return -EINVAL;
  	}
  
  	if (direction == TRANSFER_READ) {
  		err = read_packet(udev, request, (u8 *)registers, start, count);
  		if (err > 0)
  			err = 0;
  	} else if (direction == TRANSFER_WRITE) {
  		err =write_packet(udev, request, (u8 *)registers, start, count);
  		if (err < 0) {
  			LOG("Control message failed, err val = %d\n", err);
  			LOG("Message: request = 0x%0X, start = 0x%0X\n",
  			    request, start);
  			LOG("Message: count = %d, register[0] = 0x%0X\n",
  			    count, ((unsigned char *) registers)[0]);
  		} else
  			err=0;
  	} else {
  		LOG("Unexpected first byte of direction: %d\n",
  		       direction);
  		return -EINVAL;
  	}
  
  	if(err != 0)
  		LOG("Unexpected error: %d\n", err);
  	return err;
  }
  
  
  /******************************************************************************
   *
   *  submit_urbs
   *
   *****************************************************************************/
  static int submit_urbs(struct camera_data *cam)
  {
  	struct urb *urb;
  	int fx, err, i, j;
  
  	for(i=0; i<NUM_SBUF; ++i) {
  		if (cam->sbuf[i].data)
  			continue;
  		cam->sbuf[i].data =
  		    kmalloc(FRAMES_PER_DESC * FRAME_SIZE_PER_DESC, GFP_KERNEL);
  		if (!cam->sbuf[i].data) {
  			while (--i >= 0) {
  				kfree(cam->sbuf[i].data);
  				cam->sbuf[i].data = NULL;
  			}
  			return -ENOMEM;
  		}
  	}
  
  	/* We double buffer the Isoc lists, and also know the polling
  	 * interval is every frame (1 == (1 << (bInterval -1))).
  	 */
  	for(i=0; i<NUM_SBUF; ++i) {
  		if(cam->sbuf[i].urb) {
  			continue;
  		}
  		urb = usb_alloc_urb(FRAMES_PER_DESC, GFP_KERNEL);
  		if (!urb) {
  			ERR("%s: usb_alloc_urb error!\n", __func__);
  			for (j = 0; j < i; j++)
  				usb_free_urb(cam->sbuf[j].urb);
  			return -ENOMEM;
  		}
  
  		cam->sbuf[i].urb = urb;
  		urb->dev = cam->dev;
  		urb->context = cam;
  		urb->pipe = usb_rcvisocpipe(cam->dev, 1 /*ISOC endpoint*/);
  		urb->transfer_flags = URB_ISO_ASAP;
  		urb->transfer_buffer = cam->sbuf[i].data;
  		urb->complete = cpia2_usb_complete;
  		urb->number_of_packets = FRAMES_PER_DESC;
  		urb->interval = 1;
  		urb->transfer_buffer_length =
  			FRAME_SIZE_PER_DESC * FRAMES_PER_DESC;
  
  		for (fx = 0; fx < FRAMES_PER_DESC; fx++) {
  			urb->iso_frame_desc[fx].offset =
  				FRAME_SIZE_PER_DESC * fx;
  			urb->iso_frame_desc[fx].length = FRAME_SIZE_PER_DESC;
  		}
  	}
  
  
  	/* Queue the ISO urbs, and resubmit in the completion handler */
  	for(i=0; i<NUM_SBUF; ++i) {
  		err = usb_submit_urb(cam->sbuf[i].urb, GFP_KERNEL);
  		if (err) {
  			ERR("usb_submit_urb[%d]() = %d\n", i, err);
  			return err;
  		}
  	}
  
  	return 0;
  }
  
  /******************************************************************************
   *
   *  cpia2_usb_stream_start
   *
   *****************************************************************************/
  int cpia2_usb_stream_start(struct camera_data *cam, unsigned int alternate)
  {
  	int ret;
  	int old_alt;
  
  	if(cam->streaming)
  		return 0;
  
  	if (cam->flush) {
  		int i;
  		DBG("Flushing buffers\n");
  		for(i=0; i<cam->num_frames; ++i) {
  			cam->buffers[i].status = FRAME_EMPTY;
  			cam->buffers[i].length = 0;
  		}
  		cam->curbuff = &cam->buffers[0];
  		cam->workbuff = cam->curbuff->next;
  		cam->flush = false;
  	}
  
  	old_alt = cam->params.camera_state.stream_mode;
  	cam->params.camera_state.stream_mode = 0;
  	ret = cpia2_usb_change_streaming_alternate(cam, alternate);
  	if (ret < 0) {
  		int ret2;
  		ERR("cpia2_usb_change_streaming_alternate() = %d!\n", ret);
  		cam->params.camera_state.stream_mode = old_alt;
  		ret2 = set_alternate(cam, USBIF_CMDONLY);
  		if (ret2 < 0) {
  			ERR("cpia2_usb_change_streaming_alternate(%d) =%d has already "
  			    "failed. Then tried to call "
  			    "set_alternate(USBIF_CMDONLY) = %d.\n",
  			    alternate, ret, ret2);
  		}
  	} else {
  		cam->frame_count = 0;
  		cam->streaming = 1;
  		ret = cpia2_usb_stream_resume(cam);
  	}
  	return ret;
  }
  
  /******************************************************************************
   *
   *  cpia2_usb_stream_pause
   *
   *****************************************************************************/
  int cpia2_usb_stream_pause(struct camera_data *cam)
  {
  	int ret = 0;
  	if(cam->streaming) {
  		free_sbufs(cam);
  		ret = set_alternate(cam, USBIF_CMDONLY);
  	}
  	return ret;
  }
  
  /******************************************************************************
   *
   *  cpia2_usb_stream_resume
   *
   *****************************************************************************/
  int cpia2_usb_stream_resume(struct camera_data *cam)
  {
  	int ret = 0;
  	if(cam->streaming) {
  		cam->first_image_seen = 0;
  		ret = set_alternate(cam, cam->params.camera_state.stream_mode);
  		if(ret == 0) {
  			/* for some reason the user effects need to be set
  			   again when starting streaming. */
  			cpia2_do_command(cam, CPIA2_CMD_SET_USER_EFFECTS, TRANSFER_WRITE,
  					cam->params.vp_params.user_effects);
  			ret = submit_urbs(cam);
  		}
  	}
  	return ret;
  }
  
  /******************************************************************************
   *
   *  cpia2_usb_stream_stop
   *
   *****************************************************************************/
  int cpia2_usb_stream_stop(struct camera_data *cam)
  {
  	int ret;
  
  	ret = cpia2_usb_stream_pause(cam);
  	cam->streaming = 0;
  	configure_transfer_mode(cam, 0);
  	return ret;
  }
  
  /******************************************************************************
   *
   *  cpia2_usb_probe
   *
   *  Probe and initialize.
   *****************************************************************************/
  static int cpia2_usb_probe(struct usb_interface *intf,
  			   const struct usb_device_id *id)
  {
  	struct usb_device *udev = interface_to_usbdev(intf);
  	struct usb_interface_descriptor *interface;
  	struct camera_data *cam;
  	int ret;
  
  	/* A multi-config CPiA2 camera? */
  	if (udev->descriptor.bNumConfigurations != 1)
  		return -ENODEV;
  	interface = &intf->cur_altsetting->desc;
  
  	/* If we get to this point, we found a CPiA2 camera */
  	LOG("CPiA2 USB camera found\n");
  
  	cam = cpia2_init_camera_struct(intf);
  	if (cam == NULL)
  		return -ENOMEM;
  
  	cam->dev = udev;
  	cam->iface = interface->bInterfaceNumber;
  
  	ret = set_alternate(cam, USBIF_CMDONLY);
  	if (ret < 0) {
  		ERR("%s: usb_set_interface error (ret = %d)\n", __func__, ret);
  		kfree(cam);
  		return ret;
  	}
  
  
  	if((ret = cpia2_init_camera(cam)) < 0) {
  		ERR("%s: failed to initialize cpia2 camera (ret = %d)\n", __func__, ret);
  		kfree(cam);
  		return ret;
  	}
  	LOG("  CPiA Version: %d.%02d (%d.%d)\n",
  	       cam->params.version.firmware_revision_hi,
  	       cam->params.version.firmware_revision_lo,
  	       cam->params.version.asic_id,
  	       cam->params.version.asic_rev);
  	LOG("  CPiA PnP-ID: %04x:%04x:%04x\n",
  	       cam->params.pnp_id.vendor,
  	       cam->params.pnp_id.product,
  	       cam->params.pnp_id.device_revision);
  	LOG("  SensorID: %d.(version %d)\n",
  	       cam->params.version.sensor_flags,
  	       cam->params.version.sensor_rev);
  
  	usb_set_intfdata(intf, cam);
  
  	ret = cpia2_register_camera(cam);
  	if (ret < 0) {
  		ERR("%s: Failed to register cpia2 camera (ret = %d)\n", __func__, ret);
  		kfree(cam);
  		return ret;
  	}
  
  	return 0;
  }
  
  /******************************************************************************
   *
   *  cpia2_disconnect
   *
   *****************************************************************************/
  static void cpia2_usb_disconnect(struct usb_interface *intf)
  {
  	struct camera_data *cam = usb_get_intfdata(intf);
  	usb_set_intfdata(intf, NULL);
  
  	DBG("Stopping stream\n");
  	cpia2_usb_stream_stop(cam);
  
  	mutex_lock(&cam->v4l2_lock);
  	DBG("Unregistering camera\n");
  	cpia2_unregister_camera(cam);
  	v4l2_device_disconnect(&cam->v4l2_dev);
  	mutex_unlock(&cam->v4l2_lock);
  	v4l2_device_put(&cam->v4l2_dev);
  
  	if(cam->buffers) {
  		DBG("Wakeup waiting processes\n");
  		cam->curbuff->status = FRAME_READY;
  		cam->curbuff->length = 0;
  		if (waitqueue_active(&cam->wq_stream))
  			wake_up_interruptible(&cam->wq_stream);
  	}
  
  	DBG("Releasing interface\n");
  	usb_driver_release_interface(&cpia2_driver, intf);
  
  	LOG("CPiA2 camera disconnected.\n");
  }
  
  static int cpia2_usb_suspend(struct usb_interface *intf, pm_message_t message)
  {
  	struct camera_data *cam = usb_get_intfdata(intf);
  
  	mutex_lock(&cam->v4l2_lock);
  	if (cam->streaming) {
  		cpia2_usb_stream_stop(cam);
  		cam->streaming = 1;
  	}
  	mutex_unlock(&cam->v4l2_lock);
  
  	dev_info(&intf->dev, "going into suspend..\n");
  	return 0;
  }
  
  /* Resume device - start device. */
  static int cpia2_usb_resume(struct usb_interface *intf)
  {
  	struct camera_data *cam = usb_get_intfdata(intf);
  
  	mutex_lock(&cam->v4l2_lock);
  	v4l2_ctrl_handler_setup(&cam->hdl);
  	if (cam->streaming) {
  		cam->streaming = 0;
  		cpia2_usb_stream_start(cam,
  				cam->params.camera_state.stream_mode);
  	}
  	mutex_unlock(&cam->v4l2_lock);
  
  	dev_info(&intf->dev, "coming out of suspend..\n");
  	return 0;
  }
  
  /******************************************************************************
   *
   *  usb_cpia2_init
   *
   *****************************************************************************/
  int cpia2_usb_init(void)
  {
  	return usb_register(&cpia2_driver);
  }
  
  /******************************************************************************
   *
   *  usb_cpia_cleanup
   *
   *****************************************************************************/
  void cpia2_usb_cleanup(void)
  {
  	schedule_timeout(2 * HZ);
  	usb_deregister(&cpia2_driver);
  }
  