V4L/DVB (3376): Add cpia2 camera support

There has been a CPIA2 driver out of kernel for a long time and it has
been pretty clean for some time too. This is an import of the
sourceforge driver which has been stripped of
- 2.4 back compatibility
- 2.4 old style MJPEG ioctls
A couple of functions have been made static and the docs have been
repackaged into Documentation/video4linux.  The rvmalloc/free functions now
match the cpia driver again.  Other than that this is the code as is.
Tested on x86-64 with a QX5 microscope.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 907 insertions, 0 deletions

diff --git a/drivers/media/video/cpia2/cpia2_usb.c b/drivers/media/video/cpia2/cpia2_usb.c
new file mode 100644
index 0000000..f4da029
--- /dev/null
+++ b/drivers/media/video/cpia2/cpia2_usb.c
@@ -0,0 +1,907 @@
+/****************************************************************************
+ *
+ *  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@redhat.com>
+ ****************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/usb.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, struct pt_regs *);
+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 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,
+	.id_table	= cpia2_id_table
+};
+
+
+/******************************************************************************
+ *
+ *  process_frame
+ *
+ *****************************************************************************/
+static void process_frame(struct camera_data *cam)
+{
+	static int frame_count = 0;
+
+	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, struct pt_regs *regs)
+{
+	int i;
+	unsigned char *cdata;
+	static int 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 || !cam->present || cam->open_count == 0) {
+		LOG("Will now stop the streaming: streaming = %d, "
+		    "present=%d, open_count=%d\n",
+		    cam->streaming, cam->present, cam->open_count);
+		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");
+			do_gettimeofday(&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(!cam->present)
+		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
+ *
+ *****************************************************************************/
+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;
+
+	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) {
+			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) {
+			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) {
+		ret = set_alternate(cam, USBIF_CMDONLY);
+		free_sbufs(cam);
+	}
+	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) {
+			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");
+
+	if((cam = cpia2_init_camera_struct()) == 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_register_camera(cam)) < 0) {
+		ERR("%s: Failed to register cpia2 camera (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);
+		cpia2_unregister_camera(cam);
+		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);
+
+	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);
+	cam->present = 0;
+
+	DBG("Stopping stream\n");
+	cpia2_usb_stream_stop(cam);
+
+	DBG("Unregistering camera\n");
+	cpia2_unregister_camera(cam);
+
+	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);
+
+	if (cam->open_count == 0) {
+		DBG("Freeing camera structure\n");
+		kfree(cam);
+	}
+
+	LOG("CPiA2 camera disconnected.\n");
+}
+
+
+/******************************************************************************
+ *
+ *  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);
+}