pwc-if.c

linux内核源码

	spin_lock_irqsave(&pdev->ptrlock, flags);
	/* First grab our read_frame; this is removed from all lists, so
	   we can release the lock after this without problems */
	if (pdev->read_frame != NULL) {
		/* This can't theoretically happen */
		PWC_ERROR("Huh? Read frame still in use?\n");
		spin_unlock_irqrestore(&pdev->ptrlock, flags);
		return ret;
	}


	if (pdev->full_frames == NULL) {
		PWC_ERROR("Woops. No frames ready.\n");
	}
	else {
		pdev->read_frame = pdev->full_frames;
		pdev->full_frames = pdev->full_frames->next;
		pdev->read_frame->next = NULL;
	}

	if (pdev->read_frame != NULL) {
		/* Decompression is a lenghty process, so it's outside of the lock.
		   This gives the isoc_handler the opportunity to fill more frames
		   in the mean time.
		*/
		spin_unlock_irqrestore(&pdev->ptrlock, flags);
		ret = pwc_decompress(pdev);
		spin_lock_irqsave(&pdev->ptrlock, flags);

		/* We're done with read_buffer, tack it to the end of the empty buffer list */
		if (pdev->empty_frames == NULL) {
			pdev->empty_frames = pdev->read_frame;
			pdev->empty_frames_tail = pdev->empty_frames;
		}
		else {
			pdev->empty_frames_tail->next = pdev->read_frame;
			pdev->empty_frames_tail = pdev->read_frame;
		}
		pdev->read_frame = NULL;
	}
	spin_unlock_irqrestore(&pdev->ptrlock, flags);
	return ret;
}

/**
  \brief Advance pointers of image buffer (after each user request)
*/
void pwc_next_image(struct pwc_device *pdev)
{
	pdev->image_used[pdev->fill_image] = 0;
	pdev->fill_image = (pdev->fill_image + 1) % pwc_mbufs;
}

/**
 * Print debug information when a frame is discarded because all of our buffer
 * is full
 */
static void pwc_frame_dumped(struct pwc_device *pdev)
{
	pdev->vframes_dumped++;
	if (pdev->vframe_count < FRAME_LOWMARK)
		return;

	if (pdev->vframes_dumped < 20)
		PWC_DEBUG_FLOW("Dumping frame %d\n", pdev->vframe_count);
	else if (pdev->vframes_dumped == 20)
		PWC_DEBUG_FLOW("Dumping frame %d (last message)\n",
				pdev->vframe_count);
}

static int pwc_rcv_short_packet(struct pwc_device *pdev, const struct pwc_frame_buf *fbuf)
{
	int awake = 0;

	/* The ToUCam Fun CMOS sensor causes the firmware to send 2 or 3 bogus
	   frames on the USB wire after an exposure change. This conditition is
	   however detected  in the cam and a bit is set in the header.
	   */
	if (pdev->type == 730) {
		unsigned char *ptr = (unsigned char *)fbuf->data;

		if (ptr[1] == 1 && ptr[0] & 0x10) {
			PWC_TRACE("Hyundai CMOS sensor bug. Dropping frame.\n");
			pdev->drop_frames += 2;
			pdev->vframes_error++;
		}
		if ((ptr[0] ^ pdev->vmirror) & 0x01) {
			if (ptr[0] & 0x01) {
				pdev->snapshot_button_status = 1;
				PWC_TRACE("Snapshot button pressed.\n");
			}
			else {
				PWC_TRACE("Snapshot button released.\n");
			}
		}
		if ((ptr[0] ^ pdev->vmirror) & 0x02) {
			if (ptr[0] & 0x02)
				PWC_TRACE("Image is mirrored.\n");
			else
				PWC_TRACE("Image is normal.\n");
		}
		pdev->vmirror = ptr[0] & 0x03;
		/* Sometimes the trailer of the 730 is still sent as a 4 byte packet
		   after a short frame; this condition is filtered out specifically. A 4 byte
		   frame doesn't make sense anyway.
		   So we get either this sequence:
		   drop_bit set -> 4 byte frame -> short frame -> good frame
		   Or this one:
		   drop_bit set -> short frame -> good frame
		   So we drop either 3 or 2 frames in all!
		   */
		if (fbuf->filled == 4)
			pdev->drop_frames++;
	}
	else if (pdev->type == 740 || pdev->type == 720) {
		unsigned char *ptr = (unsigned char *)fbuf->data;
		if ((ptr[0] ^ pdev->vmirror) & 0x01) {
			if (ptr[0] & 0x01) {
				pdev->snapshot_button_status = 1;
				PWC_TRACE("Snapshot button pressed.\n");
			}
			else
				PWC_TRACE("Snapshot button released.\n");
		}
		pdev->vmirror = ptr[0] & 0x03;
	}

	/* In case we were instructed to drop the frame, do so silently.
	   The buffer pointers are not updated either (but the counters are reset below).
	   */
	if (pdev->drop_frames > 0)
		pdev->drop_frames--;
	else {
		/* Check for underflow first */
		if (fbuf->filled < pdev->frame_total_size) {
			PWC_DEBUG_FLOW("Frame buffer underflow (%d bytes);"
				       " discarded.\n", fbuf->filled);
			pdev->vframes_error++;
		}
		else {
			/* Send only once per EOF */
			awake = 1; /* delay wake_ups */

			/* Find our next frame to fill. This will always succeed, since we
			 * nick a frame from either empty or full list, but if we had to
			 * take it from the full list, it means a frame got dropped.
			 */
			if (pwc_next_fill_frame(pdev))
				pwc_frame_dumped(pdev);

		}
	} /* !drop_frames */
	pdev->vframe_count++;
	return awake;
}

/* This gets called for the Isochronous pipe (video). This is done in
 * interrupt time, so it has to be fast, not crash, and not stall. Neat.
 */
static void pwc_isoc_handler(struct urb *urb)
{
	struct pwc_device *pdev;
	int i, fst, flen;
	int awake;
	struct pwc_frame_buf *fbuf;
	unsigned char *fillptr = NULL, *iso_buf = NULL;

	awake = 0;
	pdev = (struct pwc_device *)urb->context;
	if (pdev == NULL) {
		PWC_ERROR("isoc_handler() called with NULL device?!\n");
		return;
	}

	if (urb->status == -ENOENT || urb->status == -ECONNRESET) {
		PWC_DEBUG_OPEN("URB (%p) unlinked %ssynchronuously.\n", urb, urb->status == -ENOENT ? "" : "a");
		return;
	}
	if (urb->status != -EINPROGRESS && urb->status != 0) {
		const char *errmsg;

		errmsg = "Unknown";
		switch(urb->status) {
			case -ENOSR:		errmsg = "Buffer error (overrun)"; break;
			case -EPIPE:		errmsg = "Stalled (device not responding)"; break;
			case -EOVERFLOW:	errmsg = "Babble (bad cable?)"; break;
			case -EPROTO:		errmsg = "Bit-stuff error (bad cable?)"; break;
			case -EILSEQ:		errmsg = "CRC/Timeout (could be anything)"; break;
			case -ETIME:		errmsg = "Device does not respond"; break;
		}
		PWC_DEBUG_FLOW("pwc_isoc_handler() called with status %d [%s].\n", urb->status, errmsg);
		/* Give up after a number of contiguous errors on the USB bus.
		   Appearantly something is wrong so we simulate an unplug event.
		 */
		if (++pdev->visoc_errors > MAX_ISOC_ERRORS)
		{
			PWC_INFO("Too many ISOC errors, bailing out.\n");
			pdev->error_status = EIO;
			awake = 1;
			wake_up_interruptible(&pdev->frameq);
		}
		goto handler_end; // ugly, but practical
	}

	fbuf = pdev->fill_frame;
	if (fbuf == NULL) {
		PWC_ERROR("pwc_isoc_handler without valid fill frame.\n");
		awake = 1;
		goto handler_end;
	}
	else {
		fillptr = fbuf->data + fbuf->filled;
	}

	/* Reset ISOC error counter. We did get here, after all. */
	pdev->visoc_errors = 0;

	/* vsync: 0 = don't copy data
		  1 = sync-hunt
		  2 = synched
	 */
	/* Compact data */
	for (i = 0; i < urb->number_of_packets; i++) {
		fst  = urb->iso_frame_desc[i].status;
		flen = urb->iso_frame_desc[i].actual_length;
		iso_buf = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
		if (fst == 0) {
			if (flen > 0) { /* if valid data... */
				if (pdev->vsync > 0) { /* ...and we are not sync-hunting... */
					pdev->vsync = 2;

					/* ...copy data to frame buffer, if possible */
					if (flen + fbuf->filled > pdev->frame_total_size) {
						PWC_DEBUG_FLOW("Frame buffer overflow (flen = %d, frame_total_size = %d).\n", flen, pdev->frame_total_size);
						pdev->vsync = 0; /* Hmm, let's wait for an EOF (end-of-frame) */
						pdev->vframes_error++;
					}
					else {
						memmove(fillptr, iso_buf, flen);
						fillptr += flen;
					}
				}
				fbuf->filled += flen;
			} /* ..flen > 0 */

			if (flen < pdev->vlast_packet_size) {
				/* Shorter packet... We probably have the end of an image-frame;
				   wake up read() process and let select()/poll() do something.
				   Decompression is done in user time over there.
				   */
				if (pdev->vsync == 2) {
					if (pwc_rcv_short_packet(pdev, fbuf)) {
						awake = 1;
						fbuf = pdev->fill_frame;
					}
				}
				fbuf->filled = 0;
				fillptr = fbuf->data;
				pdev->vsync = 1;
			}

			pdev->vlast_packet_size = flen;
		} /* ..status == 0 */
		else {
			/* This is normally not interesting to the user, unless
			 * you are really debugging something */
			static int iso_error = 0;
			iso_error++;
			if (iso_error < 20)
				PWC_DEBUG_FLOW("Iso frame %d of USB has error %d\n", i, fst);
		}
	}

handler_end:
	if (awake)
		wake_up_interruptible(&pdev->frameq);

	urb->dev = pdev->udev;
	i = usb_submit_urb(urb, GFP_ATOMIC);
	if (i != 0)
		PWC_ERROR("Error (%d) re-submitting urb in pwc_isoc_handler.\n", i);
}


int pwc_isoc_init(struct pwc_device *pdev)
{
	struct usb_device *udev;
	struct urb *urb;
	int i, j, ret;

	struct usb_interface *intf;
	struct usb_host_interface *idesc = NULL;

	if (pdev == NULL)
		return -EFAULT;
	if (pdev->iso_init)
		return 0;
	pdev->vsync = 0;
	udev = pdev->udev;

	/* Get the current alternate interface, adjust packet size */
	if (!udev->actconfig)
		return -EFAULT;
	intf = usb_ifnum_to_if(udev, 0);
	if (intf)
		idesc = usb_altnum_to_altsetting(intf, pdev->valternate);

	if (!idesc)
		return -EFAULT;

	/* Search video endpoint */
	pdev->vmax_packet_size = -1;
	for (i = 0; i < idesc->desc.bNumEndpoints; i++) {
		if ((idesc->endpoint[i].desc.bEndpointAddress & 0xF) == pdev->vendpoint) {
			pdev->vmax_packet_size = le16_to_cpu(idesc->endpoint[i].desc.wMaxPacketSize);
			break;
		}
	}

	if (pdev->vmax_packet_size < 0 || pdev->vmax_packet_size > ISO_MAX_FRAME_SIZE) {
		PWC_ERROR("Failed to find packet size for video endpoint in current alternate setting.\n");
		return -ENFILE; /* Odd error, that should be noticeable */
	}

	/* Set alternate interface */
	ret = 0;
	PWC_DEBUG_OPEN("Setting alternate interface %d\n", pdev->valternate);
	ret = usb_set_interface(pdev->udev, 0, pdev->valternate);
	if (ret < 0)
		return ret;

	for (i = 0; i < MAX_ISO_BUFS; i++) {
		urb = usb_alloc_urb(ISO_FRAMES_PER_DESC, GFP_KERNEL);
		if (urb == NULL) {
			PWC_ERROR("Failed to allocate urb %d\n", i);
			ret = -ENOMEM;
			break;
		}
		pdev->sbuf[i].urb = urb;
		PWC_DEBUG_MEMORY("Allocated URB at 0x%p\n", urb);
	}
	if (ret) {
		/* De-allocate in reverse order */
		while (i--) {
			usb_free_urb(pdev->sbuf[i].urb);
			pdev->sbuf[i].urb = NULL;
		}
		return ret;
	}

	/* init URB structure */
	for (i = 0; i < MAX_ISO_BUFS; i++) {
		urb = pdev->sbuf[i].urb;

		urb->interval = 1; // devik
		urb->dev = udev;
		urb->pipe = usb_rcvisocpipe(udev, pdev->vendpoint);
		urb->transfer_flags = URB_ISO_ASAP;
		urb->transfer_buffer = pdev->sbuf[i].data;
		urb->transfer_buffer_length = ISO_BUFFER_SIZE;
		urb->complete = pwc_isoc_handler;
		urb->context = pdev;
		urb->start_frame = 0;
		urb->number_of_packets = ISO_FRAMES_PER_DESC;
		for (j = 0; j < ISO_FRAMES_PER_DESC; j++) {
			urb->iso_frame_desc[j].offset = j * ISO_MAX_FRAME_SIZE;
			urb->iso_frame_desc[j].length = pdev->vmax_packet_size;
		}
	}

	/* link */
	for (i = 0; i < MAX_ISO_BUFS; i++) {
		ret = usb_submit_urb(pdev->sbuf[i].urb, GFP_KERNEL);
		if (ret)
			PWC_ERROR("isoc_init() submit_urb %d failed with error %d\n", i, ret);
		else
			PWC_DEBUG_MEMORY("URB 0x%p submitted.\n", pdev->sbuf[i].urb);
	}

	/* All is done... */
	pdev->iso_init = 1;
	PWC_DEBUG_OPEN("<< pwc_isoc_init()\n");
	return 0;
}

static void pwc_iso_stop(struct pwc_device *pdev)
{
	int i;

	/* Unlinking ISOC buffers one by one */
	for (i = 0; i < MAX_ISO_BUFS; i++) {
		struct urb *urb;

		urb = pdev->sbuf[i].urb;
		if (urb != 0) {
			PWC_DEBUG_MEMORY("Unlinking URB %p\n", urb);
			usb_kill_urb(urb);
		}
	}
}

static void pwc_iso_free(struct pwc_device *pdev)
{
	int i;

	/* Freeing ISOC buffers one by one */
	for (i = 0; i < MAX_ISO_BUFS; i++) {
		struct urb *urb;

		urb = pdev->sbuf[i].urb;
		if (urb != 0) {
			PWC_DEBUG_MEMORY("Freeing URB\n");
			usb_free_urb(urb);
			pdev->sbuf[i].urb = NULL;
		}
	}
}

void pwc_isoc_cleanup(struct pwc_device *pdev)
{
	PWC_DEBUG_OPEN(">> pwc_isoc_cleanup()\n");
	if (pdev == NULL)
		return;
	if (pdev->iso_init == 0)
		return;

	pwc_iso_stop(pdev);
	pwc_iso_free(pdev);

	/* Stop camera, but only if we are sure the camera is still there (unplug
	   is signalled by EPIPE)
	 */
	if (pdev->error_status && pdev->error_status != EPIPE) {
		PWC_DEBUG_OPEN("Setting alternate interface 0.\n");
		usb_set_interface(pdev->udev, 0, 0);
	}

	pdev->iso_init = 0;
	PWC_DEBUG_OPEN("<< pwc_isoc_cleanup()\n");
}

int pwc_try_video_mode(struct pwc_device *pdev, int width, int height, int new_fps, int new_compression, int new_snapshot)
{
	int ret, start;

	/* Stop isoc stuff */
	pwc_isoc_cleanup(pdev);
	/* Reset parameters */
	pwc_reset_buffers(pdev);
	/* Try to set video mode... */
	start = ret = pwc_set_video_mode(pdev, width, height, new_fps, new_compression, new_snapshot);
	if (ret) {
		PWC_DEBUG_FLOW("pwc_set_video_mode attempt 1 failed.\n");
		/* That failed... restore old mode (we know that worked) */
		start = pwc_set_video_mode(pdev, pdev->view.x, pdev->view.y, pdev->vframes, pdev->vcompression, pdev->vsnapshot);
		if (start) {
			PWC_DEBUG_FLOW("pwc_set_video_mode attempt 2 failed.\n");
		}
	}
	if (start == 0)
	{
		if (pwc_isoc_init(pdev) < 0)
		{
			PWC_WARNING("Failed to restart ISOC transfers in pwc_try_video_mode.\n");
			ret = -EAGAIN; /* let's try again, who knows if it works a second time */
		}
	}
	pdev->drop_frames++; /* try to avoid garbage during switch */
	return ret; /* Return original error code */
}

/*********
 * sysfs
 *********/
static struct pwc_device *cd_to_pwc(struct device *cd)
{
	struct video_device *vdev = to_video_device(cd);
	return video_get_drvdata(vdev);
}

static ssize_t show_pan_tilt(struct device *class_dev,
			     struct device_attribute *attr, char *buf)
{
	struct pwc_device *pdev = cd_to_pwc(class_dev);
	return sprintf(buf, "%d %d\n", pdev->pan_angle, pdev->tilt_angle);
}

static ssize_t store_pan_tilt(struct device *class_dev,
			      struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct pwc_device *pdev = cd_to_pwc(class_dev);
	int pan, tilt;
	int ret = -EINVAL;

	if (strncmp(buf, "reset", 5) == 0)
		ret = pwc_mpt_reset(pdev, 0x3);

	else if (sscanf(buf, "%d %d", &pan, &tilt) > 0)
		ret = pwc_mpt_set_angle(pdev, pan, tilt);

	if (ret < 0)
		return ret;
	return strlen(buf);
}
static DEVICE_ATTR(pan_tilt, S_IRUGO | S_IWUSR, show_pan_tilt,
		   store_pan_tilt);

static ssize_t show_snapshot_button_status(struct device *class_dev,
					   struct device_attribute *attr, char *buf)
{
	struct pwc_device *pdev = cd_to_pwc(class_dev);
	int status = pdev->snapshot_button_status;
	pdev->snapshot_button_status = 0;
	return sprintf(buf, "%d\n", status);
}

static DEVICE_ATTR(button, S_IRUGO | S_IWUSR, show_snapshot_button_status,
		   NULL);

static int pwc_create_sysfs_files(struct video_device *vdev)